Hardy ahmad

(Animal husbandry-Dairy cow) By:Hardy Ahmad Karim
Review Article
ffects of rearing, grazing, stocking rate, breed
and fed different fats on milk production in a
dairy cow
PREPARED BY
HARDY AHMAD KARIM
DIRECTED BY
DR.AYHAN YILMAZ
AGRICULTURE FACULTY IN THE SIIRT UNIVERSITY
2015-2016
Summary
Livestock are commonly kept in many refugee situations and, in many instances, form an
important part of community activities. They are also a fundamental requirement in many
returnee situations given the broad range of products which they can provide.
In addition to the selected products high- lighted below, additional reasons for enhancing
livestock-keeping practices in refugee and returnee operations include:
➤ limiting the negative impacts of certain animal species onthe environment;
➤ reducing conflicts with local communities over resource use;
➤ developing livelihood security options for refugees and returnees;
➤ encouraging trade based on livestock- keeping;
➤ preventing outbreaks and the spread of dis- eases to other herds as well as to people; and
➤ ensuring that livestock products are safe for human consumption.
E
ANIMAL
COMMONUSE
Food By-products
Bees Honey Beeswax
Fish Meat Bones (fertilizer)
Rabbits Meat Skins, manure
Poultry Meat, eggs Manure
Pigs Meat Manure
Sheep Meat,milk Skins, manure
Goats Meat,milk Skins, manure
Cattle Meat,milk,blood Skins, manure
Camels Meat,milk Skins

In both refugee and returnee situations, however,thecircumstancesgoverninglivestock
keeping may vary considerably - from being activelyprohibited,tobeingtoleratedoractual- ly
openly accepted in some formal sense. Wherever livestock are kept, however, one can reliably
expect these to have some impact on the environmental, social and economic situations of
refugees andreturnee communities.
Although livestock-keeping has such a potentially important role to play in refugee- related
situations through enhancing human welfare and providing livelihood security, in most instances
livestock keeping is largely unregulated. In consequence, complaints are commonly aired by local
people, especiallywith relation to competition for natural resources (grazing land and water in
particular), as well as health and disease associated with livestock. Large animal herds are also
often an attraction for bandits, whose presence in a refugee or returnee operation can destabilise
events.
UNHCR’s1998publication,Livestock in Refugee Situations, was the organisation’s first step towards
describing some of the common concerns relating to livestock issues in refugee settings. With new
experiences and approaches being tried and recognised, however, this guide- line is now too
restricted in its coverage to provide ample assistance to staff and partner organisations
responsible for advising on this significant issue. Toreach a better understand- ing of what the
most appropriate forms of livestock keeping and management might be for specific refugee
operations, UNHCR has therefore developed this Handbook on Livestock- Keeping and Animal
Husbandry in Refugee and Returnee Situations. Intended as a practical user-guide for selected
range of practi- tioners, this Handbook is expected to fill an important gap in the management
tools and guidelines available to UNHCR staff and implementing partners, in particular.
For management purposes, and in order to avoid or minimise the level of environmental
degradation and preserve relations with host communities and government agencies, the process
of livestock-keeping and management, in particular, needs to be taken into account at the earliest
possible stage of all refugee and returnee operations and reviewed regularly thereafter.
This Handbook is aimed largely at man- agers and generalists - not livestock specialists - the
intention being to explain, using practical experiences where possible, some of the most common
impacts associated with keeping livestock, to identify what concerns need to be addressed,
and to illustrate a range of options which might be taken or adapted to suit a particular situation.
Particular emphasis is given to the fact that users of this Handbook will be working with people
who may be already famil- iar with keeping livestock. Pastoralists from many African and Central
Asian states, for example, have long traditional associations with livestock keeping and good
animal husbandry practices. Users of this Handbook should therefore expect to learn from such
people, but should also find themselves in a position where they might be able to assist and
advise herders and others of options that might be available or better suited to a particular
refugee or returnee situation.

Introduction
Dairy farming needs a hard working, determined and patient person. The aspiring dairy farmer
must know there are no holidays throughout the year. Dairy cattle have to be fed, watered,
cleansed, their health monitored continuously and milked everyday at specified times. Milking
intervals must be kept constant (adhered to).
A dairy farmer must have basic training in bookkeeping and keep records on the running of the
dairy and artificial insemination (A.I.). Dairy cattle have to be loved and treated carefully for if a
farmer treats them roughly, they will retain their milk, which will result in mastitis.
The dairy manager or farmer should have a very good working relationship with his farm workers.
Where possible a dairy farmer should produce his/her own fodder because 75% of the farms
income is spent on feed.
Unproductive cattle should be culled, as it would be costly to keep them on the farm. There
should be constant supply of milk, therefore dairy cattle oestrus (heat) should be desynchronised
and 75% of the herd should be in milk at any given time.
Milking machines must be serviced regularly to ensure efficient and effective operations failing
which the cow’s udder will be lost through inflammation of the udder given the high pressures.
Strict hygiene should be kept at all times in the open cow sheds (kraals) in the milking parlour and
the cows should be kept clean.
After milking the cows udder should be disinfected and kept standing for at least five (5) minutes
to enable closure of the sphincter muscle in the teat canal.
When hand milking is practiced, milkers should always be clean and to wash hands thoroughly
with soap before milking and after using the toilets. Milkers should not have cuts on their hands
and should not be suffering from any contagious disease.
Dairy cattle should be stall-fed and not to move distances grazing because the energy they use to
move long distances grazing could be used for milk synthesis.

Importanceofdairycattle
Dairy cattle make a major contribution to both national and household economies as well as
provide milk, which contains essential nutrients. milk contributes significantly to meeting the
human requirements for animal protein and is especially important in the diet of children
and the sick.
regionally, dairy cattle farming contributes to employment on the farm (production), during
value addition (processing) and marketing. the farming also supports a large service sector
that offers specialized services in nutrition and health.
increase in human population has resulted in pressure on arable land leading to deterioration of
soil fertility and deforestation. manure from dairy cattle plays a major role in improving soil
fertility and it is a source of energy (biogas) for the household.
Qualitiesofagooddairycow
though milk production may not be 100% related to the external appearance of a dairy cow,
some physical features are related to milk yield and the longevity (length of time animal is
productive) of the animal in the herd. these features (figure 1.1, table 1.1) are commonly
used in judging the goodness of a dairy cow from its external appearance. these
characteristics should be considered by dairy farmers while buying, selling or culling dairy
animals.
Rump loin area top line
Udder attachment
angle at
hock
Hoof diagonal
Figure 1. Parts of the dairy cow.

table 1. characteristics used in judging dairy cattle
physiology character Description Desired
size size stature (height in cm at
rump or withers)
Jersey = 120, Guernsey =125,
ayrshire = 130, friesian = 135
chest width Distance between the
front legs
should be large to give room for the
heart and lungs
rump width Distance between the
pin bones
should be big to ease calving and
allow wide rear udder attachment
Dairy
character
angularity
Body frame
Dairy type
reflects the appearance
that the cow has the will
to milk
rib structure: ribs wide apart, rib
bones wide, flat, long and free from
excess flesh
neck: long, lean and blending
smoothly into shoulders
Barrel: width tending to increase
towards rear
rump angle
(pelvicangle)
angle from hooks to
pins
pins should be slightly lower than
hooks (about 2.5 cm). improper angle
can hinder reproductive performance
and mobility
topline level of backbone from
shoulders to pelvis
should be strong and level
Udder fore udder
attachment
attachment to trunk attachment of fore udder totrunk
should be almost level
Udder depth Distance between
bottom of udder and
ground in relation to
height
should be shallow and above the
hock. Deep udder is prone to injury.
consider age and stage of lactation
rear udder
height
Distance between vulva
and udder fold
should be attached high
Udder
suspension
Udder cleft—suspensory
ligament
should be clearly visible and
continue upwards. should be strong
to keep udder firm and prevent teats
from pointing outwards
teat placement Direction of teats should point straight down or slightly
inwards (for ease of milking)
teatlength 5 cm ideal for machinemilking;
slightly longer for hand milking
legs and
feet
rear leg set angle at hock viewed
from side should not be
straight
ideally, pin bone, hock and dew claw
should be in one line. should be
straightfromtherear
Hoof diagonal Distance between point
of toe and top of heel
intermediate desirable

HowtoBodyConditionScore
Scoringconsistentlyrequireshandlingcattleinordertoassess body reserves but an overall visual
inspection is also important. The scoring system is designed to cover all cattle but some allowance
should be made for different breeds.
Thescoringmethodinvolvesamanualassessmentofthe thicknessoffatcoverandprominenceof
boneatthetail head and loinarea.
Youshouldstanddirectlybehindthecowtoscorebothareas andalwayshandletheanimalquietlyand
carefullyusingthe same hand.
Thetailheadisscoredbyfeelingfortheamountoffataround the tailhead and the prominence of the
pelvic bones.
The loin is scored by feeling the horizontal and vertical projections of the vertebrae and the amount
of fat in-between.
Assessmentreliesmainlyon the tailheadbut isrefinedby the loinscoreifbothareverydifferent.On
ascaleof1-5,ascoreof1 is extremely thin and a score of 5 is extremely fat. If possible assess the
scores to the nearest halfpoint.
Consistency in the technique is the key to good condition scoring.
ImportanceofBodyCondition
The important stages of productionare:-
Pre-calving Conditionshouldbe“fitnotfat”,and (drying
off) should be such to allow a moderate level
of supplementation to prepare cows for early
lactation.
At calving Cowsshouldnotcalveinanexcessivelyfat
condition. Fat cowsmaydevelop fatty liver disease
or ketosis and are more prone to milk fever, mastitis,
lameness and infertility.
Early Lactation Dairy cows are under considerable nutritional stress
and adequate feeding is essential to avoidexcessive
weightloss.Excessivelythin cows can suffer
discomfort in a housing environment such as
cubicles.
At service Dairycowsshouldnotbeinenergydeficitby this
stageasthismayresultinlowfertility.

Description of Scores

Materials and Methods (1) Reference(1)
Animals, Treatments and Design: Twenty-four Jersey cows of about 350 kg, in their second
lactation, and which had calved 6-17 weeks previously, were used. They were allocated to 6
groups of 4 cows by weight and stage of lactation. Four dietary treatments were imposed
according to a Latin square design, and the squares were thus repeated 6 times, each group of
cows consisting of one replicate. The dietary treatments were:
Pasture alone (Control)
Pasture plus 250 g formal-casein/d in 0.5 litres of water (Formal-casein)
Pasture plus 2 kg fresh Leucaena leucocephala forage/d (2 Leucaena)
Pasture plus 4 kg fresh Leucaena leucocephala forage/d (4 Leucaena).
Experimental periods were of 14 d; 9 d adaptation and 5 d measurement.
Management and Procedures
Pastures: Well established pastures of Rhodes grass (Chloris gayana cv. Pioneer) which had
received 250 kg/ha/year single superphosphate, and 250 kg/ha/year nitrogen, during the main
growing season prior to the experiment were used. The area was divided into 6 plots, each
receiving 100 kg N/ha as urea 3 weeks before the start of the experiment, and the same amount
every 4 weeks thereafter.
Legume: Leucaena leucocephala (Cultivar Peru) which had been cut to ground level 3 months
previously, and fertilized with 250 kg single superphosphate and 120 kg potassium chloride/ha,
was harvested at a height of 1.5 - 2.0 metres. Leaves, stem (4 mm diameter) and green pods were
collected 1-2 d before feeding and stored at 5 C.
Protection of Casein: A 10% solution of formaldehyde was sprayed into a revolving feed mixer
containing 100 kg casein, at a rate of 0.1 litre/kg casein. The formaldehyde treated casein was
then kept in open plastic container for 24 hr before being dried for 16 hr at 50 C in a forced
fraught oven and stored in sealed plastic bags until use. Degradation by rumen bacteria (in vitro)
was measured using the method of Ferguson et al (1967).
Management: The pastures were rotationally grazed so as to provide 3 weeks for regrowth of
herbage. All cows grazed together and each day were allocated a fresh strip of pasture
containing not less than 40 kg DM/cow/d. Water was provided at all times in the pasture. The
cows were milked twice daily (06.30 -07.30 and 15.30 -
16.30 fur). The supplements were given after the morning milling. Cows on the Formal-casein
treatment were dosed using a 2.5 litre bottle filled with a polyethylene pipe 20 cm long and 5 cm
in diameter. The leucaena was fed to cows in individual
pens and was eaten in less than 1 hr. The cows on the Control treatment remained in the yard
while the supplements were being fed to the other cows.
Milk Yield and Composition: The yield of individual cows was recorded and a 1% aliquot taken at
each milking. The samples were bulked (within cows) for each period and analysed for fat by the
TeSa method for total solids (AOAC 1965), and SNF was obtained by difference. Protein was
measured with amido black (Pro-milk) standardised by the Kjeldahl method (N x 6.38).

Forage Composition: Samples of pasture were taken from each pasture plot, four
0.5 m quadrats being taken during the first 3 d of each measurement period. Three non-lactating
Jersey cows fitted with oesophageal fistulae were also used to obtain samples. Samples were
analysed for nitrogen, organic matter, nitrogen solubility in mineral buffer (Burroughs et al 1950)
and in vitro digestibility (Minson and McLeod 1972).
Results(1)
Composition of Forage and Supplements: It was evident from the higher value for N of the sample
obtained from the oesophageal fistulated animals that the cows selected a diet higher in N (Table
1). The herbage selected by the cows contained an
Table 1:
Composition of Rhodes grass pasture and Leucaena leucocephala used in the experiment
Pasture Leucaena
By cutting
By cutting Oesophageal fistula
Crude protein, %DM 14.9 18.2 23.0
Protein solubility %1
31.8 - 21.1
Digestibility OM, %2
61.9 62.5 63.0
1950)Determined using mineral buffer (Burroughs et al1
1972)Organic matter digestibility in vitro (Minson and McLeod2
average of 87% leaf, 11% stem and 2% senescent material. Crude protein solubility was
significantly different (P< .01) between the N fertilized pastures and leucaena herbage (31.8 vs
21.1% DM). Only 4.5% of the formal-casein was deaminated by rumen micro-organises in vitro
compared with 82.8% for untreated casein.
Milk Yield and Composition: These are shown in Table 2. There was an increase in milk
production (P <.001) by the supplemented cows compared with the Control. Treatment with
formal-casein gave an increase of 5% and that of leucaena 7%. There were no differences
between the two levels of leucaena supplementation.
Supplementation with formal-casein increased milk protein concentration (P <.01), whereas the
leucaena decreased milk protein concentration (P< .05). There were no other effects on milk
composition. However, when the data are expressed as yield, then both formal-casein and
leucaena increased butterfat (P<.01), protein (P <.001)

Table 2:
Milk yield of Jersey cows grazing nitrogen fertilized Rhodes grass (Chloris gayana) and
supplemented with 250 g formal-casein or 2 or 4 kg of Leucaena leucocephala (means of 24)
Control Formal 2 leucaena 4 leucaena SEx P1
casein
Milk yield, litres/d 9.6 10.1 10.3 10.3 0.10 ***
Butterfat,% 4.9 5.0 4.9 4.9 0.06 NS
Protein %2
3.70 3.80 3.64 3.64 0.02 ***
Solids-not-fat % 9.10 9.14 9.08 9.08 0.05 NS
Butterfat g/d 470 504 502 503 7.1 **
Protein g/d2
356 385 374 374 3.2 ***
Solids-not-fat, g/d 873 927 933 933 10.6 ***
1
Probability of "F" test NS>.05; ** P<.07; *** P<.007
2
N x 6.38
and solids not fat (SNF) (P <.001) yields. There were no differences between leucaena and
fonmalcasein in providing better butterfat and SNP yields. However, formal-casein
supplementation resulted in greater (P <.05) protein yields than leucaena (there were no
differences in leucaena level). The casein:total protein ratio remained constant at about 0.67
irrespective of treatment.
Discussion(1)
From the factors of Milford and Minson (1965), the extrusa samples of the pasture which had a
mean of 18.2% CP (Table 1), would have contained 12.9% digestible crude protein (DCP). It was
estimated that the daily consumption of organic matter by the unsupplemented cows was about
9.2 kg/d, and therefore the intake of pop was about 1.5 kg/d. The pop requirement for 350 kg
cows producing 9.6 kg milk/d is 722 g (ARC 1965). The cows in this experiment were therefore
consuming about twice as much pop as required. It could therefore be assumed (Grover and
Dougall 1961; Hardison 1966) that milk production from cows grazing tropical grasses at a young
stage of growth is limited by the quantity of digestible energy consumed/d, and not by the level
of pop. These calculations are based on the assumption that the quantity of plant and microbial
protein entering the small intestine is similar to the quantity of pop eaten. The protein in the
fresh grass used here was 32% soluble (Table 1).
Protein synthesis in the rumen of the unsupplemented cows can be calculated to have been
between 0.35 and 1.09 kg/d (taking a daily intake of 5.75 kg DDM, 60% degraded in the rumen
with microbial production of 9.7 - 30.7 g/100 g DDM (Walker et al 1975). Thus if rumen synthesis
of microbial protein was at the lower end of the scale, the cows would have been deficient in
protein according to the feeding standards cited. That they were capable to responding to
supplemental protein (as formal-casein) was clearly demonstrated, and is in agreement with the
results of Stobbs et al (1977), who observed a 20% increase in milk production as a response to
formal-casein, despite the fact that their cows were grazing a pasture with 20% CP in

(Animal husbandry-Dairy cow) By:Hardy
Ahmad Karim
DM. If the casein was not protected, then they only observed a 3% rise. The
mechanism involved is difficult to ascertain due to the problem of predicting
accurately voluntary intake of pasture under grazing conditions (Langlands 1975;
Minson et al 1976). However, post-ruminal feeding of amino acids are known to
effect secretion of glucagon, insulin and growth hormones, all of which are active
regulators of metabolism (Machlin 1973; Clarke 1975), and it is possible that
abomasal supplementation with casein operates through a similar mechanism.
The leucaena had a lower nitrogen solubility than the Rhodes grass, but the
protective mechanism is unknown (Hegarty, private communication). However,
since it is likely that retention time of the legume in the rumen is less than than for
grass (Thornton and Minson 1973), the amount of nitrogen irreversibly lost via
production of ammonia in the rumen could be considerably reduced. In this
context, it is of interest that there was no additional response to the higher level (4
kg) of Lachine, whereas the response to protected casein is known to increase up
to 500-1000 g/d (Clarke 1975; Spires et al 1973; Stobbs et al 1977). Responses to
leucaena as a protected protein supplement are not limited to milk production.
When fed as a supplement to steers on a basal diet of sugar cane, liveweight gains
were comparable with those of steers supplemented with meat meal (Sievert et al
1975).
Conclusions(1)
The results of this experiment have important practical implications. Small quantities
of leucaena can give useful increases in milk production at low cost, since it is
possible to produce 10-22 tons of edible DM/ha (Hutton and Beattie 1976). It is also
one of the few tropical legumes that is persistent under both cutting or grazing
regimes. Any detrimental effect due to the amino acid, mimosine, is unlikely to
influence animal health or performance when leucaena constitutes such a small
proportion of the diet. Restricted grazing of the legume for 30-60 minutes daily
before the cows are allowed onto pasture could be one practical method of
supplementation. The important point arising from this study is that the need for
the concentrate supplementation could be reduced or even eliminated

Ahmad Karim
materials and methods(2) Reference(2)
TheexperimentwasperformedattheorganicdairyfarmoftheARECRaumberg-
Gumpenstein (680 m altitude, 7°C average temperature, 1014 mm precipitation year-1
;
latitude: 47° 31/ 03/ / N; longitude: 14° 04‘26‘‘E). A total of 33 dairy cows (13 Brown
Swiss, 20 Holstein Friesian; lactation number 2.7) were assigned to three calving date
groups in 2008 and 2009. The mean calving dates were 17 November (group 1), 25
December (group 2) and 20 February (group 3). During winter period all cows were
housed and fed ad libitum with forage (grass silage, hay). Concentrate was
distributed according to lactation period and milk yield, varyingfrom 0 to 7 kg DM
cow-1
day-1
. At the beginning of the grazing period grass silage and concentrate
amount were continuously reduced. Grass silage feeding was completed at the
beginning of the day and night grazing period (30 April). Hay was offered restrictedly
(1.5 kg DM cow-1
day-1
) and concentrate was only fed to cows exceeding 28 kg daily
milk yields (28-30 kg daily milk yield: 1 kg concentrate; > 30 kg daily milk yield: 2 kg
concentrate cow-1
day-1
). At the end of lactation and during the dry period, cows in the
cowshed got 4 kg hay and grass silage ad libitum. All cows were on the same pasture
for 202 or 203 days (12 April-1 Nov. 2008; 15 April-3 Nov. 2009) with 177 day and
night grazing days. The permanent grassland area was continuously grazed at a
sward height between 4-6 cm (Ø 4.7 cm - Filip`s Folding Plate Pasture Meter). During
the stable period, forage intake was recorded by 5-day recor- ding periods each
week using Calan gates. During the grazing season, at the end of lactation and in the
dry period, feed intake was calculated according to the energy requirements (GfE,
2001). Nutrient and energy content of grass silage, hay and concentrate were
analysed from samples pooled over six weeks (Dlg, 1997). Grazed pasture nutrient
content was measured on simulated grazing plots which were cut when sward
reached an average height of 8.5 cm (Starz et al., 2011) and the energy content was
calculated according to GfE (1998). Individual milk production was recorded twice
daily and the milk ingredients were analysed three times a week. Cows were weighed
weekly and the body condition was scored every second week. At the beginning of
the grazing season blood samples were taken after morning milking every two
weeks. Data were analysed using the MIXED procedure of the statisticalprogram
package SAS 9.2 with the fixed effects ,calving group‘, ,breed‘, ‚lactation number‘,
,year‘,
,lactation week‘ and ,pregnancy group‘ and the continuous covariate ,ECM-milk yield
atthe beginning of the lactation‘ (ddfm = kr; repeated statement cow within year;
type compound symmetry). Statistical differences were considered to be significant
when P < 0.05 and tended to be significant when 0.05 < P < 0.10.

Ahmad Karim
Results and discussion(2)
According to the results of Steinwidder et al. (2010) and Pötsch et al. (2010) grazed
pasture samples showed a high net energy (6.4 ± 0.33 MJ NEL kg-1
DM) and CP
content (22 % ± 3 kg-1
DM). The energy contents of hay and grass silage (5.4 and 5.8
MJ NEL kg-1
DM resp.) and the CP contents (15% and 12% resp.) were markedly lower
than that of pasture herbage. Calving at the beginning of the vegetation period
significantly depressed lactation length and milkfatyieldandtendedinadecreased
energy-corrected-milk(ECM)yield(Table1).Contrary to group 3, the lactation curves
in groups 1 and 2 showed a second peak at the beginning of the grazing season.
Similar results on the lactation curves have been reported in New Zealand for autumn-
and spring-calved cows by Auldist et al. (1997) and Garcia et al. (1998). From group 1
to 3 the amount of concentrate fed per cow decreased from 669 to 373 kg DM and
the grazed pasture proportion increased from 43 to 50% of total feeding ration per
year. The calving date had no effects on frequency of veterinary treatments and
reproductive performance. The average pregnancy rate and calving interval was
85% and 365 days respectively. Nevertheless 14% of the pregnant cows had a calving
interval > 415 days which indicates repeated fertility problems of these cows. At the
beginning of the grazing season live weight and body condition losses, as well as the
blood contents of beta-hydroxy-butyric acid, free fatty acids and aspartate
transaminase were highest in group 3. In terms of management, it has to be taken
into account that in group 1 all cows were bred in the winter feeding period and in
group 3 during the grazing season. In group 2 the end of the grazing season fitted best
with the cows’drying-off period. The milk sales revenues (milk yield and contents,
premiums for winter milk) and the pasture area requirements decreased and the
feeding costsincreased from group 1 to 3.
Table 1. Effects of calving date on milk yield and composition of the diet
Group
1 2 3 s
e
P-value
Lactation length (days) 299 a
297 a
284b
9 0.019
ECM (kg cow-1
) 6.300 5.974 5.449 305 0.068
Milk (kg cow-1
) 6.360 6.135 5.727 703 0.258
Fat (kg cow-1
) 261 a
245 ab
217b
28 0.026
Protein (kg cow-1
) 200 189 178 19 0.149
Fat (g kg-1
milk) 410 400 379 29 0.091
Protein (g kg-1
milk) 315 308 311 17 0.612
Live weight (kg) 595 550 571 39 0.069
Hay (kg DM cow-1
year-1
) 1.075 a
981 b
957b
32 <0.001
Grass silage (kg DM cow-1
year-1
) 1.830 1.780 1.668 209 0.359
Grazed pasture (kg DM cow-1
year-1
) 2.670 b
2.856 ab
3.046a
249 0.032
Concentrate (kg DM cow-1
year-1
) 669 a
541 ab
373b
146 0.004

Ahmad Karim
Conclusions(2)
Theseasonofthecalvingperiodmarkedlyinfluencedtheresultsofthepasture-based
seasonal milk production in mountainous region. Delaying calving date from middle
of November to the end of February (group 1-3) significantly depressed lactation
length and milk fat yield and tended to decrease energy-corrected-milk yield cow-1
y-1
.
The amount of concentrate fed cow-1
y-1
decreased and the grazed pasture proportion
of total feeding ration increased from group 1 to 3. At the beginning of the grazing
season live weight loss and the contents of βHBA, FFA and AST in blood samples
were highest for cows in group3.

Ahmad Karim
Materials and Methods(3) Reference(3)
A detailed description of the experimental treatments and sward measurements has
been reported previously in a compan- ion paper on the effects of grazing pressure
on sward characteristics (Stakelum and Dillon, 2007), therefore only a brief
description is outlined in this paper. Twoexperiments (E1 and E2) were carried out at
Moorepark Research Centre in 1986 (E1) and 1987 (E2). The same experimental site
was used in both years consisting of swards with 80 to 90% perennial ryegrass (Lolium
perenne L.) and some Agrostis and Poa species. The experimental site consisted of
21 equal-sized (0.472 ha) paddocks. In both years preliminary grazing took place
with the aim of harvesting the grass that had accumulated over the winter/spring
months. This occurredfrom 9 April to 23 April in E1 and from 2 April to 18 April in E2.
Afterwards, the grazing season was divided into two periods. In Period 1 (P1) the
swards were condi- tioned, by imposing three different rota- tional grazing pressures
(GP) using dairy cows. This took place between 28 April and 20 July in E1, and
between 18 April and 21 June in E2. In Period 2 (P2) the resulting swards were grazed
at two stocking rates (SR) by dairy cows from 22 July to 10 October in E1, and from
26 June to 5 October in E2. Sixty-three spring-calving Friesian dairy cows balanced
for calving date, parity and milk yield were randomly assigned to three groups in E1.
In E2, sixty similarcowsweresimilarlyassigned.
The sward types (ST) produced as a result of the low, medium and high GPin P1
are termed low (LQ), medium (MQ) and high (HQ) quality. At the beginning ofP2
eachpaddockwassub-dividedinthe ratio 0.57:0.43.This allowed two SR, with
equal numbers of cows, to be applied to each sward type. The two SR were high
(HR) and low (LR). In both E1 and E2 cows were blocked into groups of 6 on the
basis of parity, calving date and milk yield, andwithinblockwererandomlyassignedto
6 treatment groups. No first parity animals were used. Average daily pre-experimental
milk yield and composition were 19.0 (s.d. 2.25) kg and 24.5 (s.d. 2.33) kg containing
3.51 (s.d. 0.400) g and 3.41 (s.d. 0.361)g fat per 100 g milk and 3.22 (s.d. 0.225) g and
3.20 (s.d. 0.182) g protein per 100 g milk, for E1 and E2, respectively. Average parity
and calving date (days from January 1) were 5.3 (s.d. 2.28) and 48 (s.d. 39.3) for E1,
and 4.4 (s.d. 2.43) and 68 (s.d. 33.4) for E2,respectively.Averagepre-experimental
body weight was 533 (s.d. 48.1) kg and 512 (s.d. 43.6) kg for E1 and E2,respectively.
Sward measurements
Sward measurements in P2 were recorded during rotations 1, 2 and 3 in E1, and dur-
ing rotations 1, 2, 3 and 4 in E2. The details of these measurements were described by
Stakelum and Dillon (2007). Pre-grazing herbage samples were analysed fororgan- ic
matter digestibility (OMD) as described in Stakelum and Dillon (2007).

Ahmad Karim
Herbageselected
In P2, 4 and 6 oesophageal fistulated (OF) cows were grazed with the experimental
cows in each of grazing rotations 1 to 3 and 1 to 4 of E1 and E2, respectively. The OF
cows were allocated to each of the grazing treatments in a balanced design,
remaining in each paddock for the 3 days of sampling. An OF sample was obtained
after evening milking on the three successive days. Approximately 2 to 3 kg of
extrusa was collected from each animal at each sampling. After discarding excess
saliva, a sub-sample of approximately 1 kg was retained. This was immediately stored
ina freezer at 20 
C.
The extrusa samples were subsequently thawed and two sub-samples were taken.
The first sub-sample (ca. 100 g) was placed in an aluminium tray, stored again in a
freezer at –20 
C and later freeze-dried and analysed for OMD by the procedure of
Morgan and Stakelum (1987) as modified by Morgan, Stakelum and O’Dwyer
(1989). The second sub-sample (ca. 200 g) was separated into different sward com-
ponents using a point analysis technique similar to that described by Heady and Torell
(1959). Portions (ca. 20 to 30 g) of this sub-sample were placed in a 30 cm  20 cm
grided water tray. Plant components which coincided with an intersection of the grid
were identified. The components enumerated were live leaf (LL), live stem (LS), dead
leaf (DL) and dead stem (DS). The procedure continued until 100 con- tacts were
identified. Samples were analysed in duplicate by each of two experi- enced
recorders. The unit ofmeasurement was the frequency of occurrence per 100
occurrences and expressed as a decimal.
Animal measurements
Milk production: Cows were milked at 16:8 hour intervals. Milk yield wasrecord- ed
on 3 consecutive days per week. The concentrations of fat, protein and lactose
were determined for one successive morning and evening sample per week using a
FOSS-Let instrument (AS/M Foss, Electric, Denmark). Lactation ended when daily milk
yield decreased to 4 kg per cow per day or when cows were within 6 to 7 weeks of
calving. Live weight was recorded once weekly.
Grazing behaviour: Duration of grazing time (GT) was measured by fitting cows with
Kienzle vibracorders (Stobbs, 1970). Estimates were obtained from each cow in each
grazing rotation over 3 days in both E1 and E2. The rate of biting (BR) was recorded
after evening and morning milking on 3 consecutive days in one grazing block per
grazing rotation. A stop watch was used to measure the time taken for each animal
to make 20 prehension bites (Hodgson, 1982). Each animal was recorded in duplicate
at each measurement period. A record was discarded if the animal raised its head
from the sward before it had completed 20 bites.

Ahmad Karim
Herabge intake: The intake of herbage dry matter (DMI) and organic matter
(OMI) was estimated on 4 occasions corresponding to the first four grazing
rotations in Period 2 of E2, using the n-alkane technique of Mayes, Lamb and
Colgrove (1986), as modified by Dillon and Stakelum (1989). The technique was
based on the ratio of herbage C33 (n-tritriacontane) to dosed C32
(n-dotriacontane). Digestibility coefficients (OMDC35) were calculated from marker
concentrations of C35 (n-pentatriacontane) in both feed and faeces for each cow.
Cows were dosed twice daily (after AM and PM milking) over a 12-day period with
paper pellets containing approximately 500 mg of C32. Faecal grab samples were
collected twice daily (after milking) from each cow for the last 6 days of the 12-day
period. Faecal samples from each cow were dried for 48 h at 40 C, ground through a
1 mm screen and bulked prior to analysis. The n-alkane concentration in the
herbage for the last 6 days was obtained from the same OF extrusa samples as used
to estimate OMD of the OF extrusa samples. The C32 content of the pellets and the
C32, C33 and C35 concentration in faeces and herbage were analysed according to
a modification of the technique of Mayes et al. (1986) with direct saponification
(Dillon, 1993). Intake was calculated using the equation of Mayes et al. (1986).
Results(3)
Total and live-leaf daily herbage allowance Daily allowance of herbage DM and
LL per cow for the two experiments are shown in Table 1. The total DM and LL
allowance for each rotation are shown in
Figure 1. There was a significant increase in total DM allowance in both experi-
ments as sward quality declined from HQ to LQ (P < 0.001). Also, daily DM allow-
ance increased significantly (P < 0.001) in both experiments as SR decreased from
high to low. The LL allowance was similar for the three sward types in both experi-
ments. There was a significant increase (P < 0.001) in LL allowance in both exper-
iments as SR decreased from high to low. Total and LL allowances were significantly
lower (P < 0.05) for rotation 2 than for rotations 1 or 3 in E1. Also, total DM
allowancewassignificantlylower(P<0.05) for rotations 3 and 4 than for rotations 1
and 2 in E2. There was no difference in LL
allowance between rotations in E2.
Diet composition
The OMD and the proportions of LL and LS in the herbage selected by the OF cows
are shown in Table 2. The dead material was ignored because it formed only a

Ahmad Karim
minor component (range 0.016 to 0.047) of the diet. There were no interactions
between the main factors and rotation for any of the variables. In general, OMD (P
< 0.001) and LL (P < 0.01) decreased
Table 1. Daily dry matter allowance of total herbage and of live leaf (kg/cow) for cows
grazing three swards at two stocking rates in Experiments 1 and 2
Experiment
Herbage
component
Sward type  Stocking rate
HQ MQ LQ
s.e. Significance
ST SR ST  SR
HR LR HR LR HR LR
1 Total 16.5a 31.8bc 23.6ab 39.5c 33.1bc 52.2d 2.47 *** ***
2 Total 25.0a 38.4c 32.0b 56.6d 42.3c 68.5e 2.38 *** *** *
1 Live leaf 10.2a 17.0b 9.8a 17.2b 10.4a 16.6b 0.97 ***
2 Live leaf 15.5a 21.8b 15.7a 24.8c 15.2a 23.6bc 0.72 ***
1HR = high stocking rate; LR = low stocking rate; HQ = high quality sward;MQ = medium quality sward; LQ
=low quality sward.
ST = Sward Type; SR = Stocking Rate.
abcde Values, within rows, with a common superscript do not differ significantly.

Figure 1. The average daily total (TA) and live leaf (LL) (■) dry matter allowances for herds grazing high
quality swards at high (HH) or low (HL) stocking rates, medium quality swards at high (MH) or low (ML)
stocking rates and low quality swards at high (LH) or low (LL) stocking rates for each rotation in Experiments
1 and 2.
Table 2. Organic matter digestibility (g/g organic matter) and live leaf and live stem as proportions of total
plant fragments for the extrusa samples from oesophageal fistulated cows sampling three swards at two
stocking rates for Experiments 1 and 2
and LS (P < 0.001) increased as sward quality deteriorated from high to low in E1. Similarly, OMD
(P < 0.001) and LL (P < 0.001) decreased, and LS (P < 0.001) increased, as sward quality deteriorated
in E2. The effects of sward quality were greater for LL and LS than for OMD. The OMD (P < 0.05)
and LL (P <0.01)
increasedandLS(P<0.001)decreasedas SR fell from high to low in E1. Also, OMD (P < 0.001) and LL
(P < 0.001) increased andLS(P<0.01)decreasedwithdecreas- ing SR in E2. However, the effect of SR
on OMD was small. There was a significant interaction (P < 0.05) between ST and SR for LL in E2.
This was due to the lack of a SR effect on LL in the HQ sward but not in the MQ and LQ swards.
There were significant interactions between ST and day for OMD, LL and LS in bothE1 and E2. Also,
there were significant interactions between SR and day for OMD, LL and LS in both E1 and E2.There
were no third order interactions between the main factors and day. The pattern of change for OMD,
LL and LS in the diet for ST in both experiments as the swards were grazed down over the 3 days is
shown in Figure 2. The corresponding data for SR are shown in Figure 3. Forboth ST and SR, OMD and
LL decreased (P < 0.001) and LS increased (P < 0.001), as the swards weregrazeddown.Theseeffects
increased withincreasingseverityof grazing.
The predicted diet OMD coefficient, based on linear regression analysis, for E1 were 0.80, 0.81 and 0.82
g/g OM for sward
OMD values of 0.70, 0.75 and 0.80 g/g OM, respectively. The corresponding values for E2 were 0.77, 0.79
and 0.81 g/g OM for the same values of sward OMD. The predicted diet LL proportions for E1 were 0.71,
0.76 and 0.80 for sward LL values of 0.30, 0.50 and 0.70 g/g DM, respectively. The corresponding values for
E2 were 0.76, 0.80 and 0.84 for the same values of sward LL content.
The OMD of the OF samples was related to the LL proportion according to the expression:
OMD = 0.636 (s.e. 0.0058) + 0.226 (s.e. 0.0076)  LL (P < 0.001, n = 216, r.s.d.
= 0.020, R2
= 0.81) for E1, and OMD = 0.585 (s.e. 0.0068) + 0.249 (s.e. 0.0084)  LL (P < 0.001, n =
432, r.s.d. = 0.025, R2
=
0.67) for E2. Adding terms for either LS or DL did not significantly reduce the r.s.d.

Grazing behaviour
Average biting rate and grazing time for both experiments are summarised in Table
Biting rate decreased as sward quality deteriorated in both E1 (P < 0.001) and E2 (P < 0.05). Stocking rate had
no effect on biting rate in either experiment. There was a significant interaction between time in the plotandST in
bothexperiments(P < 0.001). The effect of ST and number of grazing on biting rate is shown in Figure 4 for both
experiments. In general, there was a more rapid decline in biting rate for the MQ and LQ swards than for the HQ
sward.
There was a significant interaction between ST and SR for grazing time in E1 (P < 0.01). There was an
increase in grazing time (ca. 60 min) as SR decreased from high to low for the MQ and LQ swards
whereas the opposite was so for the HQ sward. There was no effect of ST on grazing time in E2. There
was a decrease in grazing time (ca. 25 min) as SR decreased from high to low and the effect was consis-
tent for the three sward types.
Intake and dietary digestibility using n-alkane
The DMI, OMI and diet OMDC35 for the four grazing rotations in E2 are shown in Table 4. In general,
DMI and OMI were
lower for the LQ sward than for the HQ and MQ swards (P < 0.05). Both DMI and OMI decreased as SR
increased from low to high. Significant interactions between themaineffectsand rotationindicatedthat

Figure 3. The organic matter digestibility (OMD), live leaf (LL) and live stem (LS) content of the
herbage selected during the grazing down of the swards at high (◇) and low (□) stocking rate over three
days in Experiments 1 and 2.
Discussion(3)
Three different swards were created by imposing different GP in the spring to earlysummerperiodwith
dairycows.Many sward characteristics are interrelated. In this study, high sward digestibility wasasso-
ciated with lower pre-grazing herbage mass
Figure 4. The average milk yield per cow for each week of Experiments 1 and 2 for the three swards
and the two stocking rates (the s.e. of the main effect at each week indicated).

and daily herbage allowance. Theidentical SR imposed across the different swards resulted in different
levels of daily herbage allowance per cow across the treatments. However, because of the sward
composition differences, the allowance of live leaf was similar between ST at the same SR. The post-
grazing sward height (PGH) increased progressively with decreasing sward quality. The SR used in the
experiments were set at levels that represented the low and high ends of the range used in
commercial farming. If however, they had been set to match the availability of grass, then a larger effect
of sward quality would likely have been found.
Grazing behaviour
An increase in grazing time generally appears to be a compensating response on the part of the
animal for a decline in short-term rate of intake (Chacon and Stobbs, 1976). In the current study,
grazing time was not very sensitive to either ST or SR in E2. However, in E1 there was a significant
interaction between ST and SR. Grazing time was greater for HR compared to LR for both the MQ and
LQ swards. It was however, lower for HR compared to LR for the HQ sward. Hodgson (1985) showed
that grazing time may be reduced on particularly short swards (low pre-grazing herbage mass) similar to
the HQ sward in the present study.
Biting rate usually tends to decline as pre-grazing sward height or herbage mass increases, and as intake
per bite increases (Hodgson, 1985). The principle reason for this is that the ratio of manipulation to biting
jaw movement increases as intake per bite and the size of individual plant components prehended
increase (Chalmers et al., 1981). In the present study, thevaria- tion in biting rate was most likely a direct
response to variations in sward conditions. The reduction in biting rate for grazings 1 to 6, and as sward
quality declined, was due to the high degree of selection of LL by the cows. Live leaf is in highest
concentration in the upper part of the sward, while stem and dead material are in highest concentration
in the lower parts (Bentholm and Jacobsen, 1961). Therefore, with swards containing a high proportion of
LL, the effort in selection of live leaf is less, resulting in a high biting rate. However, with a sward
containing a low proportion of LL, biting rate is lower because of the increase in the manipulative jaw
movements associated withprehension of longer material.
In conclusion, the results of these two experiments indicate that milk yields of spring-calving dairy cows
on rotationally grazed pastures are higher in summer when high rather than low stocking rates are
applied in spring/early summer. The increased milk production was attributed to the higher intake of
herbage of higher nutritive value. There was no interaction between grazing pressure in the spring/
early summer and the subsequent stocking rate insummer/autumn period.

MATERIALS AND METHODS(4) Reference(4)
The feeding trial was repeated on each of the five dairy farms during winter (July and August) and
late spring November and December) experimental periods to coincide with the practice of feeding
forage comprised of primarily silage during the winter and pasture during the spring. Only cows that
completed the 2-mo experimental period in winter or spring were included in the datasetfor analysis.
The numbers and composition of experimental cows on each farm are presented in Table 1.
Only for Farm E could the treatments be applied concurrently. This was done by feeding different
concentrate mixes through the milking parlor concentrate feeders; one without DDGS (CONT) and one
containing 40% DDGS (DIST). The average feeding rate of concentrates in the parlor was 5 kg cow-1
d-1
,
and the average feeding rate of DDGS from the DIST concentrate was 2 kg cow-1
d-1
(as fed basis). The
DDGS in the DIST concentrate partially replaced, on an equivalent CP basis based on NRC (2001) feed
table values, dry rolled shelled corn (DRSC)/SBM and dry rolled wheat (DRW)/SBM contained in the
CONT concentrate during the winterand spring experimental periods, respectively.
Cows available during the winter and spring experimental periods were blocked by parity (1st
and 2nd
or
greater lactations), randomly assigned to treatments (CONT or DIST), and fed the treatments
individually for 2-mo continuously. Milk yield for individual cows was recorded daily electronically in the
milking parlor, and used to calculate average daily milk yield by 2-wk periods for each cow. Milk samples
from individual cows were collected at both the morning and evening milkings on one day every 2 wk
during the experimental periods and analyzed by Cooprinsem DHI Laboratory (Osorno, Chile; laboratory
accreditation by Quality Advantage ISO 17025:2005 [http://www.qualityadvantage.com/
Table 1. The number, percentage first-lactation, and days in milk data for cows that completed the 2-month
winter and spring experimental periods on each farm.
iso_17025.htm]) for fat, protein, and urea contents and somatic cell count (SCC) using near infrared
analysis (Foss Electric, Hillerød, Denmark). Individual cow milk yield, composition and component yields
for the 2-wk test periods were used in the statistical analysis. Data were analyzed as a randomized
complete block design with a cow as the experimental unit using the PROC MIXED procedure of SAS
(SAS Institute, 2004). The model included parity, treatment, and the parity by treatment interaction as
fixed effects, and cow within treatment as a random effect. Degrees of freedom were calculated using
the Kenward-Roger option (SAS Institute, 2004). The least squares mean statement was used to
determine treatment means. Statistical significance and trends were considered at P > 0.05 and P >
0.06 to P < 0.15, respectively.
Farm n
First-lactation
cows (%)
Days in milk at
trial initiation
Winter
A 231 33 148 ± 97
B 199 31 121 ± 103
C 100 33 128 ± 79
D 201 26 173 ± 124
E 130 30 129 ± 78
Spring
A 256 28 160 ± 103
B 137 24 89 ± 55
C 82 0 105 ± 55
D 169 24 146 ± 116
E 170 28 159 ± 218

The other four farms could not apply the treatments concurrently. These farms (A-D) were randomly
assigned to either a CONT to DIST or a DIST to CONT treatment sequence in a crossover design with
monthly feeding periods during the winter and spring experimental periods. The CONT or DIST
concentrates were fed to the whole herd on each of the four farms in the bunk mixed with silage prior
to milking according to their respective treatment sequence during the winter and spring experimental
periods. The average feeding rate of DDGS from the DIST concentrate was 2.5 kgcow-1
d-1
(as fed basis).
The DDGS in the DIST concentrate partially replaced, on an equivalent CP basis based on NRC (2001)
feed table values, DRSC and DRW/SBM (Farm A),high- moisture corn (HMC)/canola meal (CNM; Farm
B), DRSC/peanut meal (Farm C), and DRSC/SBM (Farm D) contained in the CONT concentrates during
the winter experimental period. During the spring experimental period, the DDGS in the DIST
concentrate partially replaced, on an equivalent CP basis, DRW/SBM (Farms A and D), HMC/CNM (Farm
B), and DRSC/wheat Middlings (Farm C). Milk yield for individual cows was recorded daily electronically
in the milking parlor (Farms A and D) or on 1 d every 2-wk by Cooprinsem DHI using meters in the
milking parlor (Farms B and C) during the experimental periods. Milk samples from individual cows
were collected at both the morning and evening milkings on 1 d every 2-wk during the experimental
periods by Cooprinsem DHI for milk composition analysis as described previously. Individual cow level
milk yield, composition and component yield data were used to calculate experimental farm level data
for each 2-wk period for statistical analysis. Data were analyzed as a crossover design with farm as the
experimental unit (St. Pierre, 2001) using the PROC MIXED procedure of SAS (SAS Institute, 2004). The
model included period, sequence, and treatment as fixed effects, and farm as a random effect.
Degrees of freedom were calculated using the Kenward-Roger option. The least squares mean
statement was used to determine treatment means. Statistical significance and trends were considered
at P >
0.05 and P > 0.06 to P < 0.15,respectively.
Samples of ryegrass (mixture of Lolium multiflorum Lam., L. perenne L. and L. ×hybridum Hausskn.)
pasture and silage were collected every 2-wk from each farm during both winter and spring
experimental periods. The ryegrass pastures were sampled by Cooprinsem personnel as described by
Rayburn (2003). Ryegrass silage samples were obtained, when silage was being fed, by Cooprinsem
personnel as described Undersander et al. (2005). The DDGS fed during the winter and spring
experimental periods on each farm were sampled by Cooprinsem staff. Samples were analyzed using
wet chemistry procedures (NFTA, 2009) for nutrient composition by AgSource Soil & Forage Lab
(Bonduel, Wisconsin, USA).
Results And Discussion(4)
The nutrient composition of ryegrass pasture and silage samples is presented in Table 2. Pasture
samples were of high quality relative to NRC (2001), and higher in quality than ryegrass silage samples.
Lower quality for ryegrass silage than pasture samples was likely related to advanced maturity for silage
harvest and nutrient losses during silage fermentation. Lower CP and higher NDF contents for late
spring than winter pasture samples were likely related to the dilution effect of greater yield during the
spring on the concentration of these nutrients. Few silage samples were analyzed for the spring
experimental

Table 2. Nutrient composition of ryegrass pasture and silage samples during the winter and spring
experimental periods.
Ryegrass
Pasture Silage
Nutrient % DM
, because pasture was the primary or sole forage fed. The nutrient composition of the DDGS samples is
presented in Table 3. The average CP content of DDGS was similar to NRC (2001), while the average
contentsof NDF and ether extract were 9%-units lower and2%-units greater, respectively, than
reported by NRC (2001). The low variation in nutrient composition observed among the samples was
expected, because the USA-supplied corn DDGS used for the experiment was from one supplier.
Coefficients of variation (standard deviation divided by mean) across many DDGS sources were 10%,
21% and 40% for CP, NDF and ether extract, respectively (NRC, 2001).
Lactation performance results for Farm E (Table 4) were analyzed as randomized complete block
design with cow as the experimental unit. Parity x treatment interactions were not detected (P >
0.15). Milk yield tended (P < 0.07) to be greater for cows fed DIST by 1.9 kg d-1
in winter and 1.8
kg d-1
in late spring. The trend for an increase in milk yield for cows fed DIST may have been related
to the high RUP and fat concentrations for DDGS (NRC, 2001). Responses to RUP in pasture-fed cows
were equivocal in the review of Bargo et al. (2003), who did not find trials with DDGS. Milk
composition was unaffected by treatment in the winter, however, milk fat yield tended (P < 0.11) to
be greater and milk protein yield was (P < 0.02) greater for cows fed DIST by 75 and 73 g d-1
,
respectively, in relationship to the trend for greater milk yield observed for DIST. Milk fat content
was (P < 0.01) lower for cows fed DIST by 0.26%-units in the spring, however, milk fat yield was
unaffected by treatment. In agreement with our findings, reduced milk fat content with no change
in yield of fat in response to feeding DDGS was reported by Leonardi et al. (2005). High content of
unsaturated fatty acids in DDGS (Leonardi et al., 2005) is the probable cause of
depression in milk fat content (Bauman and Griinari, 2000) observed in response to feeding
DDGS. This
Winter
Crude protein
Neutral detergentfiber
Acid detergentfiber
n = 19
29.2 ± 4.6
41.8 ± 6.3
27.2 ± 4.8
n = 21
15.0 ± 4.1
46.6 ± 5.7
29.8 ± 3.3
Total digestible nutrients2
67.7 ± 7.1 65.7 ± 5.0
Spring n = 38 n = 2
Crude protein 22.7 ± 5.3 13.0 ± 1.1
Neutral detergentfiber 44.0 ± 5.2 49.8 ± 9.9
Acid detergentfiber 27.2 ± 2.9 29.8 ± 6.1
Total digestible nutrients2
67.7 ± 4.3 65.7 ± 9.1

Table 3. Nutrient composition of the distillery dried grains fed throughout theexperiment1
.
Table 4. Treatment effects on lactation performance least squares means for Farm E where data were
analyzed as a randomized complete block design with cows as the experimental unit.
Item Control Distillery dried grains SEM (P<)
Winter
Milk yield, kg d-1
29.1 31.0 0.8 0.07
Fat, % 4.17 4.09 0.07 NS2
Fat, g d-1
1212 1287 34 0.11
Protein, % 3.42 3.38 0.05 NS
Protein, g d-1
989 1062 24 0.02
Urea, mg L-1
612 619 10 NS
SCC3, x 1000 132 157 36 NS
Spring
Milk yield, kg d-1
32.9 34.7 1.0 0.07
Fat, % 3.68 3.42 0.08 0.01
Fat, g d-1
1193 1180 35 NS
Protein, % 3.51 3.45 0.04 NS
Protein, g d-1
1146 1196 29 0.09
Urea, mg L-1
354 357 9 NS
SCC, x 1000 95 97 49 NS
SEM: Standard error of the mean; NS: Non significant; SCC: Somatic cell count.
response may be more pronounced during the spring when pasture comprises most of the dietary
forage and the content of unsaturated fatty acids in pasture is the highest (Chilliard et al., 2000). Other
milk composition measurements (protein, urea and SCC) were unaffected by treatment in the spring.
Milk protein yield tended (P < 0.09) to be greater for cows fed DIST by 50 g d-1
during the spring in
relationship to the greater milk yield observed for DIST.
Lactation performance results for Farms A-D (Table 5) were analyzed using a mixed models procedure
with period, sequence and treatment as fixed effects and farm within sequence as a random effect.
Milk yield in winter was (P < 0.05) greater for farms fed DIST by 0.9 kg d-1
. Milk fat (P < 0.07) and protein
(P < 0.06) contentstended to be lower for farms fed DIST in Winter, however, fat and protein contents
for these farms when fed DIST (3.99% and 3.37%, respectively) were not indicative of a depression in
milk composition (Pulido et al., 2009), and yields of fat and protein were unaffected by treatment. Milk
urea and SCC were unaffected by treatment in winter. The feeding of DIST during the late spring did
not affect milk yield, composition or component yields on these farms. The lack of milk yield response
to DDGS in the spring for the 4-farm combined analysis may have been related to higher quality forage
from pasture in the spring more closely meeting the nutrient requirements for milk production. We
have no explanation for why this may have occurred, however, for Farms A-D and not Farm E. But, it is

possible that differences in pasture management among the farms may have affected the milk yield
response observed during the spring feeding period. The consistent lack of treatment effects on milk
urea and SCC across all farms and both experimental periods indicates that feeding DDGS was not
adverse to these cow health related measurements.
CONCLUSIONS(4)
Distillery dried grains (2.0 to 2.5 kg cow-1
d-1
) were an effective dairy concentrate ingredient in the
pasture region of southern Chile under the conditions of this study. Longer-term lactation trials and
studies withhigher inclusion amounts for distillery dried grains are warranted. Potential combined effects
of unsaturated fatty acids from distillers dried grains and spring pasture on reduced milk fat content
merits further study.

Material and methods(5) Reference(5)
A continuous grazing experiment was conducted in Ås, Norway, with sixteen Norwegian Red dairy cows
(80 ± 15.0 days in milk (d.i.m.)) with three 3-week periods of measurements: in June, July and
September 2008. The cows were blocked by genetic line, d.i.m. and milk yield and were allocated
randomly to the two treatments: a grass-red clover pasture (GR) in the first production year, and a five-
year-old pasture including sown and unsown species of grass, clover and other herbs (GCH) with a daily
dry matter (DM) allowance of approximately 20 kg cow-1
d-1
and supplemented with 3.0 kg d-1
of barley
pellets, including minerals. Both pastures were organically managed. A period with indoor silage feeding
before grazing was used as a baseline period. Both groups were grazing together between the three3-
periods on pastures similar to GCH. GR contained 54% grasses, 28% red clover, 1% white clover and 17%
other herbs, and GCH contained 66% grasses, 3% red clover, 21% white clover and 10% other
herbs as estimated with the dry-weight-rank method (Mannetje and Haydock, 1963). Pasture intake
was estimated as net energy requirement for lactation and maintenance minus net energy in
concentrates divided by net energy concentration in pasture samples. Individual pooled samples from
four consecutive milkings in each period were analysed for the content of fat, protein, free FA,
vitamins, phytoestrogens, FA composition and milk oxidative stability. Milk oxidative stability was
analysed in a light exposure experiment (three replicates were exposed for light for 0, 24 or 48 hours at
4 ºC) by determination of lipid hydroperoxides as described by Østdal et al. (2000) and front face
fluorescence spectroscopy as described by Veberg et al. (2007). Milk composition variables were
analysed using the mixed model procedure by SAS 9.2 with treatment, period and treatment-period
interaction as fixed effects and cow within treatment, and block as random effects accounting for
repeated measurement on cow. The statistical model for hydroperoxides included also fixed effects of
light exposure and treatment-light exposure interaction. For milk yield and milk chemical composition
the baseline data were used as a covariate. The fluorescence emission spectra were analysed in a
principal component analysis (Unscrambler).
Table 1. Pasture dry matter intake, milk yield and milk composition from cows grazing swards of grass-
red clover (GR) or sown and unsown species of grass, clover and herbs (GCH)
GR GCH SED Pa
Pasture DM intake (est.), kg day
-1 15.4 15.3 0.76 NS
Milk yield, kg d
-1 24.6 24.9 0.74 NS
Fat, g kg
-1 37.7 37.2 1.04 NS
Protein, g kg
-1 33.6 33.2 0.82 NS
Free FA, meq L-1 0.49 0.62 0.122 NS
Total saturated FA, g per 100 g FAME
b 66.72 68.37 1.032 NS
Total monounsaturated FA, g per 100 g FAME 28.35 26.93 0.820 NS
Total polyunsaturated FA, g per 100 g FAME 4.95 4.70 0.314 NS
n-6:n-3 FA ratio 2.00 1.89 0.120 NS
β-caroten, mg L
-1 0.25 0.24 0.022 NS
α-tocopherol, mg L
-1 1.51 1.32 0.082 NS
Retinol, mg L
-1 0.52 0.45 0.041 NS
Enterolactone, μg L
-1 172.3 120.9 28.54 (*)
Formononetin, μg L
-1 49.4 5.5 16.01 (*)
Equol, μg L
-1 1230.8 88.0 220.40 *
Genistein, μg L
-1 15.5 2.6 4.11 *
Biochanin A, μg L
-1 16.2 1.2 5.12 *
Hydroperoxides, after 48 h of light exposure 0.47 0.46 0.041 NS
a
P-value: NS P > 0.10, (*) P < 0.10, *P < 0.05; b
Fatty acid methylesters

Results and discussion(5)
There was no significant effect of pasture botanical composition on pasture intake, milk yield,
concentration of fat, protein and vitamins and composition of most FA in milk (Table 1). The elevating
effect of red clover diets on milk content of ALA (Dewhurst et al., 2003; Steinshamn and Thuen, 2008) is
due to the activity of polyphenol oxidase (PPO) that inhibits lipolysis (Lee et al., 2009). The activation of the
enzyme requires the presence of oxygen and occurs during mastication of fresh red clover, but it is limited
by the anaerobe condition in the rumen (Lee et al. 2009). Thus, the lack of effect in the present experiment
might be due to the short period of time the red clover is exposed to oxygen during the grazing and
mastication process. Concentrations of the phytoestrogens equol, genistein and biochanin A were
significantly higher in milk from GR than GCH. This is in accordance with other experiments where red
clover has been compared with white clover containing diets (Steinshamn et al.,2008; Andersen et al.,
2009). The milk concentrations of equol, enterolactone and formononetin from GR fed cows in the present
experiment were several times higher than found in other experiments with red clover based diets, both
from silage (Steinshamn et al., 2008; Mustonen et al., 2009) and pasture (Andersen et al., 2009). Pasture
type did not affect concentration of hydroperoxides. In the principal component analysis of the
fluorescence spectra principal component (PC) 1 explained 94% and PC2 6% of the total variation. PC1
grouped the samples by light exposure time which was correlated with reduction of the photosensitiser
riboflavin. PC2 grouped the pasture typed to some degree but the correlated tops in the fluorescence
spectra are of unknown substances and it is not sure that these are oxidation products since differences
were consistent even for samples not exposed to light.
Conclusions(5)
Pasture with red clover did not affect FA composition in milk to an extent susceptible to a higher risk of
milk fat oxidation compared to pasture including several grass species, white clover and herbs. Grazing GR
compared to GCH increased the concentrations of phytoestrogens in milk.

Materials and Methods(6) Reference(6)
This was part of a three-year research project initiated in the fall of 2003. A primary objective was to
compare 2 pasture-based systems with cows at 2 different stocking rates. Also, performance of Jersey,
Holstein, and crossbred cows would be examined within the two systems.
The project consisted of two groups of 40 cows for each of 3 years at different stocking rates. One was a
Low stocking rate of 2.5 cows/ha or 1 cow/acre receiving 1x supplementation at 8 to 16 pounds of
concentrate per head per day. The High stocking rate was 3.7 cows/haor
1.5 cows/acre with 1.5x supplementation of 12 to 24 pounds of concentrate per head per day.. Amounts of
concentrate varied depending on quantities and quality of pasture or round bale haylage and consisted of
ground corn, whole cottonseed, soybean meal, and mineral. Although the amounts of supplemented
concentrate varied throughout the lactation, the relative proportions were kept at 1.5:1 for High vs. Low
stocking rates, respectively. Round bale grass haylage was used during winter or in periods of drought
when pasture was limited or unavailable. When lush pasture was available the relative proportion of
soybean meal in the supplement was reduced as were total amounts of concentrate.
Each group of 40 cows was planned to include 13 Holstein, 13 Jersey, and 14 various Holstein x Jersey
crossbred cows. However, because of limited numbers of cows available, there were < 40 cows per group
in the 3rd
year of the study. The High stocking group had 34 cows and the Low stocking group had 35 cows.
Among the crossbred cows there were crosses varying from ¾ Holstein to ¾ Jersey and the average
percentage Holstein was 53, 49.5,and
51.4 for 2003, 2004, and 2005 calving seasons, respectively.
Pastures were set up proportionately based on soil types and forages species oneither 40 acres for the
Low group or 27 acres for the High stocking rate group. Pasture species by percentage of the acreages
included 20% improved fescue (MaxQ) plus ladino clover; 30 % winter annual ryegrass alternated with
sorghum-sudan summer annual; and 50%Tifton-44 hybrid Bermudagrass overseeded with annual ryegrass
each fall. Each group of cows also had access to two 3-acre sacrifice areas where haylage was fed as
needed and two small areas of woods for summer shade when temperatures exceeded 90 degrees F. With
calving in the fall, cows started on cool season pastures of either fescue-clover or ryegrass and moved to
sacrifice areas as needed in the winter.
Breeding via detection of estrus and artificial insemination began in January and continued through March.
Although nearly all cows were inseminated at a natural estrus, a few cows each year that were not
observed in estrus by late February were treated with an appropriate hormonal sequence so that all could
be inseminated at least once during the breeding season.

Results(6)
Table 1.Reproductive measures and SCC Scores by breed pooled over 3 years.
Std.
H J X Error
Conception
Rate at 1st 43.5
Service
51.3 66.1 ±8.3
Conception
Rate at All 40.5
Services
56.5 64.2 ±6.7
Pregnancy
Rate
76.6
91.1 91.8 ±3.0
SCC Score 3.2 3.3 3.5 ±0.17
Reproductively, there were no significant differences between the two stocking rate groups. However,
there were breed differences in measures of reproduction. Various reproductive measures for the
different breeds averaged across stocking rates and all three years of the study are included in Table 1.
Jerseys and Crossbreds had higher conception rates at 1st
service and over all services as well as having
higher pregnancy rate over the entire breeding season than Holsteins. However, the values for conception
rates among the Jerseys were lower than expected in the first year of the study, likely because they were
moved from a TMR-feeding system at another location in early lactation and had to adapt to the pasture-
based system just before the breeding season. That year resulted in perhaps a lower average conception
for the 3 years and may not precisely reflect long-term reproductive success of Jersey cows. In fact, in a
related paper in these proceedings Jerseys had numerically the highest first service conception rates at
61.4% among all cows calving in2005.
There were no significant differences in linear SCC scores by either stocking rate or breed group across the
3-year study (Table 1).
Group and breed differences in milk production levels and composition can be seen in Table 2. Typically,
the Holsteins produced the most pounds of mature-equivalent milk, fat, and protein whereas Jerseys
produced the least, and the crossbred cows were intermediate to both pure breeds. However, there was
an exception in the 2005-2006 High stocking group.Holsteins had poor production, lower than even the
Jerseys. In contrast, the crossbreds had unusually high milk production compared to other years,
surpassing the other breeds. More thorough analyses of what happened in the third year needs to be
done. Because the total numbers of animals included in year 3 was fewer than the desired 40, a few
animals withdisproportionately high or low milk yields may have skewed the results.
Differences between the 2 stocking rates were seen in that the High stocking group produced significantly
more milk, fat and protein than the Low stocking group each year and cumulatively. The advantage for the
High stocking rate group in yield measures was about 11 to 12 percent across the 3-year study.

Conclusions(6)
All 3 breeds produced at greater levels at the high stocking rate, receiving less pasture and more supplement per cow. Although amounts of concentrate
supplement fed to cows on the High stocking rate was more, higher milk yields per cow and increased productivity per unit of land because of more cows per acre
would favor High stocking rates economically as proposed by Clifton King in work on economic modeling of pasture-based systems in his M.S. thesis in 1997.
Table 2. Measures of milk production by breed and stocking rate over 3 years
H J X H J X H J X H J X
2003-2004 lb/cow lb/cow lb/cow lb/cow lb/cow lb/cow lb/cow lb/cow lb/cow % % %
ECM 13,714 11,517 13,177 14,545 12,669 14,017 -831 -1,152 -840 -6.1% -10.0% -6.4%
ME Milk 15,002 10,775 13,260 15,240 12,147 14,091 -238 -1,372 -831 -1.6% -12.7% -6.3%
ME Fat 457 412 456 494 460 488 -37 -48 -32 -8.1% -11.7% -7.0%
ME Protein 422 387 428 461 399 450 -39 -12 -22 -9.2% -3.1% -5.1%
2004-2005
ECM 15,854 10,479 12,863 16,161 12,545 14,023 -307 -2,066 -1,160 -1.9% -19.7% -9.0%
ME Milk 16,895 10,404 12,861 16,811 11,628 14,239 84 -1,224 -1,378 0.5% -11.8% -10.7%
ME Fat 533 366 449 555 470 483 -22 -104 -34 -4.1% -28.4% -7.6%
ME Protein 499 340 414 506 388 453 -7 -48 -39 -1.4% -14.1% -9.4%
2005-2006
ECM 14,667 12,122 12,516 13,619 13,896 15,365 1,048 -1,774 -2,849 7.1% -14.6% -22.8%
ME Milk 15,301 12,098 12,636 13,938 13,903 15,556 1,363 -1,805 -2,920 8.9% -14.9% -23.1%
ME Fat 486 427 438 477 488 536 9 -61 -98 1.9% -14.3% -22.4%
ME Protein 491 383 395 421 441 486 70 -58 -91 14.3% -15.1% -23.0%
All Years
ECM 14,661 11,369 12,925
SE
± 469 14,800 13,075 14,456
SE
± 465 -139 -1,706 -1,531 -0.9% -15.0% -11.8%
ME Milk 15,681 11,178 12,986 ± 486 15,401 12,578 14,622 ± 482 280 -1,400 -1,636 1.8% -12.5% -12.6%
ME Fat 489 401 450 ± 18 508 475 502 ± 18 -19 -74 -52 -3.9% -18.5% -11.6%
ME Protein 466 368 416 ± 15 465 410 463 ± 15 1 -42 -47 0.2% -11.4% -11.3%

MATERIALS AND METHODS(7) Reference(7)
Cows
At 9 wk postpartum, 35 non-gestating multiparous Holstein cows from the Trawsgoed Farm (IGER,
Aberystwyth, Wales, UK), averaging 571 kg of body weight (SE = 8 kg), were assigned to one of two dietary
treatments. All cows calved within a 35-d period. Data on production (feed intake, milk production and
composition, and FA composition of blood and milk) were collected from all cows between weeks 9 and
19 of lactation. Reproduction data (gestation rate and length of estrous cycle) were collected only from
cows that had demonstrated normal estrous cycles as determined by repeated cyclicity in milk
progesterone concentrations measured between weeks 9 and 19 postpartum. Five cows were
considered as not having normal estrous cyles; there were two cows with anoestrus and one cow with a
cyst in the MEGA treatment group and two cows with anoestrus in the FLAX treatment group. These five
cows had persistently low milk progesterone concentrations and, thus, were not inseminated. Cows were
housed in free stalls, fed individually using a Calan gate system (American Calan, Inc., Northwood, NH),
and milked twice daily at 0600 and 1600 h. Milk production was recorded at every milking. Milk samples
were obtained weekly from each cow for two consecutive milkings and analyzed separately to determine
milk composition. Cows were weighed weekly. Body condition score was determined every week using a
six-point scale (where 0 = emaciated and 5 = fat; Mulvany 1977). Animals were cared for according to the
guidelines of the Canadian Council on Animal Care (1993).
Feeding
After parturition and before the beginning of theexperiment at week 9 postpartum, all cows were fed a
common diet that
Table 1. Chemical composition of feed ingredientsz
Item Silage Concentrate Megalac® Flaxseed meal Flaxseed
pH 3.72 – – – –
DM (%) 20.4 90.1 96.9 90.3 90.7
ADF (%) 35.0 18.6 – 19.1 29.7
NDF (%) 56.1 31.8 – 27.8 47.7
Gross energy (kcal g–1) 5.15 4.60 7.93 5.01 6.15
CP (% of DM) 15.9 23.3 – 35.1 26.3
Soluble N (% of N) 49.0 – – – –
NH3 N (% of N) 13.5 – – – –
Lactic acid (% of DM) 12.0 – – – –
Acetic acid (% of DM) 1.81 – – – –
Propionic acid (% of DM) 0.19 – – – –
Isobutyric acid (% of DM) 0 – – – –
Butyric acid (% of DM) 0.01 – – – –
Valeric acid (% of DM) 0 – – – –
Ether extract (% of DM) 4.8 7.3 77.6 10.4 32.4
Fatty acid (% of total fatty
acids)C6:0 0 0.06 0.03 0 0
C8:0 0 0.33 0.06 0 0
C10:0 2.48 0.57 0.04 0.39 0.08
C12:0 0.32 3.33 0.43 0.27 0
C14:0 1.21 1.96 1.35 0.19 0.08
C14:1 1.65 0 0 0 0
C16:0 25.42 20.26 43.97 8.31 6.31
C16:1 0.82 0.71 0.24 0.03 0.08
C18:0 5.56 4.42 4.84 3.18 3.74
C18:1 3.89 32.95 39.32 18.28 18.37
C18:2 14.22 27.16 9.06 16.37 14.42
C18:3 43.49 7.85 0.32 52.92 56.78
C20:0 0.94 0.40 0.34 0.06 0.13

consisted of silage for ad libitum intake and 6 kg d–1 of a pelleted high-protein concentrate. Milk
production and composition during weeks 7 and 8 of lactation were used as covariants for subsequent
milk production and composition. Cows were introduced gradually to treatments over a 7-d period starting
week 9 postpartum. All cows received atotal mixed diet based on long-term perennial ryegrass silage and
fat supplements offered for ad libitum intake (Table 1). The grass was harvested with a precision-chop
forage harvester (Alois Pottinger MBH Mex VI PU457, Grieskirchen, Germany) and cut at a theoretical
length of 5 cm from the primary growth of a stand of mostly ryegrass (> 90%, Lolium perenne), ensiled in
bunkers, covered with plastic sheets, and weighted with straw bales. Silage was made between 3 and 6
June 1996. The chopped material was wilt- ed for 24 h to approximately 21% DM and Add Safe (Trouw
Nutrition Ltd., Northwich, UK), a mixture of 17% ammonium formate, 5% ammonium propionate, 38%
formic acid and 11% propionic acid was applied at a rate of 5 L t–1 of fresh grass. The two dietary
treatments (Table 2) consisted of fat supplements based on either solvent extracted flaxseed meal and
Megalac® (Volac Ltd., Roston, Hertfordshire, UK) (MEGA), which is a Ca-soap of FA or whole flaxseed
treated with formaldehyde (FLAX). There were 18 cows in the FLAX group and 17 cows in the MEGA group.
Treatment of FLAX was carried out by adding 300 g of formalin per kg of whole flaxseeds to create pH
reversible methylene bridges within the seed. Following treatment, the flaxseed was held for 5 d in
curing vessels to allow methyl linkages to form. Thus, the protected flaxseed was bagged and stored at
ambient temperature after the curing phase. A pelleted concentrate (Table 1) was fed to all cows at a
daily rate of 2.5 kg in one meal in the afternoonas top dress on the silage. Cows fed MEGA and FLAX diets
received, respectively, 60 and 20 g d–1 of a mineral and vitamin mixture containing 14.5% P; 5.5% Mg;
9.75% Na; 12 mg kg–1 of Se; 100 mg kg–1 of Co; 450 mg kg–1 of I; 7000 mg kg–1 of Mn; 4500 mg kg–1 of Zn;
2750 mg kg–1 of Fe; 1000 mg kg–1 of Cu; 500 000 IU kg–1 of vitamin A; 100000 IU kg–1 of vitamin D3; and 500
IU kg–1 of vitamin E. The
two treatments were designed to provide similar crude pro-
tein (CP) and oil intakes and were formulated to meet requirements for cows averaging 550 kg of body
weight, 25 kg of milk per day with 4.1% milk fat (Rumnut, The Ruminant Nutrition Program, A. T.
Chamberlain, 1994ed.). Diets were fed once daily with approximately 10% orts, and accumulated feed
refusals were taken three times a week. Feed ingredients and total mixed diets were sampled three times
a week, frozen, and composited on a 2-wk basis. Composited samples were mixed thoroughly and
subsam- pled for chemical analyses.
Measurements
Blood was collected from all cows at weeks 0 and 10 of the experiment (weeks 9 and 19 postpartum,
respectively) 3 h postfeeding. Blood was withdrawn from the jugular vein into vacutainer (Becton
Dickinson Vacutainer Systems Europe BP 37, 38241 Meylan Cedex, France) tubes contain ing heparin for
determination of insulin and glucose, into vacutainer (Becton Dickinson) tubes containing EDTA for non-
esterified FA and FA analysis, and into vacutainer tubes (Becton Dickinson) without preservative for
cholesterol analysis. The plasma and serum were separated and frozen at –20°C for subsequent analysis.
Milk was collected three times a week from the start of the experiment until 45 d after artificial
insemination for progesterone analysis. Timing of ovulations and corpora lutea formation were estimated
from sustained elevations in milk progesterone concentration (at least 7 d above 3 g L–1) as described by
Lucy et al.(1992). Ovulation was defined as occurring 5 d prior to first eleva- tion in milk progesterone or
was determined exactly for cows observed in estrus (ovulation = estrus day + 1). Estrous cycle length was
estimated as the interval between successive ovulations. Cows were observed for signs of estrus after
milking for a 30-min period two times daily from the beginning of the experiment and started to be
inseminated after 6 wk on the diets (wk 15 of lactation). Cows were inseminated 12 h after the end of
standing heat. The same two techni- cians performed the inseminations and semen came from a single
ejaculate of two bulls, ensuring that equal numbersof cows from each treatment group were bred to each
bull. Ultrasound scanning was performed on day 45 after AI to confirm pregnancy. Conception rate was
defined as the proportion of cows that were detected in estrus and inseminated that were pregnant on
day 45 post AI.

Table 2. Ingredient and chemical composition of the two total mixed diets (DM basis except DM)z
Composition MEGA FLAX
Ingredient (% of DM)
Silage 81.7 83.0
Megalac® 5.6 0
Flaxseed meal 12.7 0
Formaldehyde whole flaxseed 0 17.0
Nutrienty
DM (%) 23.2 ± 0.94 22.9 ± 1.4
CP (%) 16.7 ± 0.4 17.0 ± 0.7
NDF (%) 50.1 ± 1.4 54.5 ± 0.7
ADF (%) 30.9 ± 0.7 31.8 ± 1.1
Energy (kcal g–1) 5.10 ± 0.04 5.13 ± 0.03
Ether extract (%) 9.3 ± 0.9 10.0 ± 1.1
Ash (%) 7.7 ± 0.7 7.1 ± 0.5
Starch (%) 3.5 ± 0.2 3.9 ± 0.4
Fatty acid (% of total fatty acids)
C10:0 0.84 ± 0.11 0.78 ± 0.16
C12:0 0.30 ± 0.02 0.09 ± 0.02
C14:0 1.37 ± 0.07 0.39 ± 0.11
C14:1 0 0.40 ± 0.10
C16:0 32.13 ± 0.72 11.17 ± 1.22
C16:1 0.30 ± 0.05 0.22 ± 0.07
C18:0 3.66 ± 0.08 4.65 ± 0.36
C18:1 25.27 ± 0.82 14.58 ± 0.64
C18:2 12.49 ± 0.05 14.67 ± 0.80
C18:3 23.21 ± 0.98 52.74 ± 3.34
C20:0 0.43 ± 0.02 0.31 ± 0.05
zMEGA = fat supplement based on Megalac® and flaxseed meal and FLAX
= fat supplement based on formaldehyde treated whole flaxseed.
yMean of seven 2-wk composite samples that were prepared from three weekly samples ± standard deviation (SD).
Ovaries of eight cows per dietary treatment were examined by ultrasonography using a
ConceptMCV ultrasound scanner equipped with a linear array 7.5 MHz probe (Dynamic Imaging
Ltd, Livingston, Scotland, UK) in mid- morning on every second day during the second estrous
cycle of the experiment as determined by milk progesterone. Examinations involved removal of
faecal matter from the rectum, insertion of the probe into the rectum, and position- ing of the
probe adjacent to each ovary. Size and number of ovarian follicles > 3 mm were recorded on
detailed follicular maps designed to identify specific large follicles (> 5 mm) on repeated days.
Procedures were similar generally to those described by De La Sota et al. (1993). In this way, the
size of the largest and second largest follicles could be followed during the preovulatory period.
Cystic follicles were always associated with low milk progesterone concentrations, thus were not
considered as the largest follicles. Follicles were grouped into three diameter classes for analyses:
class 1 (3.0 to 4.9 mm), class 2 (5.0 to 9.9 mm), and class 3 ( 10 mm). Size, number, and position
of corpus luteum (CL) and large luteinized follicles also were recorded.
Chemical Analysis
Dry matter of silage was determined according to Dewar and McDonald (1981). Dry matter of
total mixed diets and other feed ingredients was obtained by drying at 100°C for 48 h. An aqueous
extract (20 g of silage in 100 mL of water) was used to determine concentrations of D- and L-
lactate (kit No. 139 084, Boehringer Mannheim Ltd., Lewes, East Sussex, UK), ammonia (kit No. 66-
50, Sigma-Aldrich Co., Ltd., Poole, Dorset, UK) with a discrete analyzer (FP-901 M Chemistry
Analyzer, Labsystems Oy, Helsinki, Finland) and pH using a pH meter (FisherBrand Hydrus 400,
Orion Research Inc, Beverly, MA). Silage volatile FA were determined by gas chromatography
(ATI Unicam, Cambridge, UK) on an aliquot of the extract using 2-ethyl-butyric acid as the internal

standard chromatography (Fussell and McCalley 1987). Soluble N was calculated as the portion
dissolved after a 2-h incubation in artificial saliva at 40°C (Merry et al. 1987). Ether extraction was
obtained using Soxtec equipment (Perstorp Analytical Ltd., Maidenhead, Berkshire, UK) with the
acid hydrolysis ether extract method incorporating the additional acid hydrolysis and extraction
step described in Thomas et al. (1988).
Crude protein (N  6.25) determinations were done by the Kjeldahl method. Neutral detergent
fibre (NDF) was determined using the modified method with amylase described by Van Soest et
al. (1991) while acid detergent fibre (ADF) was analyzed according to Van Soest and Wine (1967).
Gross energy of freeze-dried silages was measured with an adia- batic bomb calorimeter (Sanyo
Gallenkamp, Leicester, UK). Concentrations of plasma glucose (kit No. 6,Sigma-Aldrich Ltd., Poole,
Dorset, UK), plasma non-esterified FA (kit 9075401; Wako Pure Chemical Industries, Osaka,
Japan), and serum cholesterol (kit No. 352, Sigma-Aldrich Ltd., Poole, Dorset, UK) were analyzed
by colorimetric methods. Nitrogen, fat, and lactose in milk were determined by an infrared
method (National Milk Records PLC,Chippenham, UK). Plasma concentrations of insulin were
determined by radioimmunoassay using a kit (Life Screen Ltd., Watford, UK). All samples were
measured in one assay and the intra- assay coefficient of variation was < 14% and the inter-assay
variation was < 8%. Concentrations of progesterone in whole milk (Ridgeway Science Ltd,
Alvington, UK) were measured by enzyme immunoassay (Groves et al. 1990) in a single assay
every week for samples collected in the same week, and intra- and inter-assay coefficients of
variation were 4.2 and 7.5%, respectively. A total of 13 assays was carried out. The limit of
detection with the progesterone assay was 0.5 ng mL–1. Fatty acid composition of blood, milk, and
feed ingredients was carried out using the one-step saponification-methylation method of
Sukhija and Palmquist (1988). Samples were introduced to the gas chromatograph via a split
injector onto a cross-linked polyethylene glycol column (Innowax 30 m  0.32 mm  0.5 m). A
temperature gradient from 60 to 230°C effected the separation of FA methyl esters, which were
detected by a flame ionization detector. Fatty acids were identified according to their retention
time (AI-450 Software; Dionex Ltd, Camberley, Surrey, UK) using a reference standard (ME61
Quantitative; Greyhound Chromatography, West Birkenhead, Merseyside, UK). Cis-10-
nonadecenoic acid (C19:1) was added to samples as an injection standard just prior to loading
onto the gas chromatograph.
Statistical Analysis
All results were subjected to least squares ANOVA for a randomized complete block design with
two treatments using the general linear models procedure of the SAS Institute, Inc. (1985).
Data on milk production and milk composition were analyzed using the mean values for the
preceeding 2 wk as covariate. Data on blood composition were analyzed as repeated
measurements across time. Significance was declared at P < 0.05 unless otherwise stat- ed. Data
on follicular development were analyzed from days 14 to 21 of the estrous cycle. This part of the
estrous cycle includes three successive events representing: first, the end of the luteal phase or
diestrous with CL development and important secretion of progesterone; second, the follicular
phase or proestrous with PGF2 secretion, CL regression, decrease progesterone concentration,
and selection of a preovulatory follicle; and third, the estrus and ovulation with
the lowest progesterone concentration. Synthesis of PGF2 is responsible for luteolysis, thus

leading to embryo loss and
return into heat. Our hypothesis was that feeding a sourceof linolenic acid would inhibit PGF2
synthesis and improve the maintenance of gestation. Student’s t tests were used to
determine the effect of treatments on length of estrus cycle, size of CL, the difference in size
between the largest andthe second largest follicle, and class and number of follicles. The number
and percentage of cows pregnant were tested using a chi-square test.
RESULTS AND DISCUSSION(7)
Ether extract supplied by the concentrate portion represented 5.4 and 6% of the total mixed diet
for MEGA and FLAX, respectively (data not shown). Percentages of CP, NDF, and ADF were very
similar in both diets (Table 2). Dry matter intake, expressed in kilogram per day or as a
percentage of body weight, and change in body weight were similar for cows fed MEGA and FLAX
(Table 3). Untreated whole flaxseed is readily accepted by dairy cows and feeding upto 15% of
the total DM as flaxseed has no effect on DMintake (Kennelly and Khorasani 1992). There was no
difference in tail and loin body condition score, and in change of body condition score of tail and
loin (data not shown). Similar results were reported for cows fed extruded soybeans and rolled
sunflower seeds (Schingoethe et al. 1996) or 4.5% Ca salts and nonenzymatically browned
soybeans (Abel-Caines et al. 1998). Change in body weight was not affected by treatment (Table 3)
although all cows lost weight. A loss in body weight was not expected based on a study that used
a diet containing a similar silage to concentrate ratio as was used in our study (Aston et al. 1998).
However, the loss in body weight can be explained by the lower silage quality in the present
experiment; ryegrass was harvested in June in our study compared with the third week of May in
the study by Aston et al. (1998).
Milk production (Table 3) was lower than that reported by Aston et al. (1998) for cows fed similar
silage to concentrate ratio, which may be a result of the more-mature silage fed in the present
experiment. Milk production and 4% fat- corrected milk yield were higher for cows fed MEGA than
for those fed FLAX. Schingoethe et al. (1996) reported no difference in yields of milk and 4%
fat-corrected milk

Table 3. Dry matter intake (DMI), body weight (BW) change and covariant-adjusted milk
production and milk composition of Holstein cows fed between weeks 9 and 19 of lactation a total
mixed diet containing Megalac® and flaxseed meal (MEGA) or formaldehyde-treated whole flaxseed
(FLAX)z
zLeast squares means with pooled standard error (SE).
yCovariant-adjusted fat-corrected milk production at weeks 7 and 8 of lactation.
xP = 0.06.
a, b Means within a row with a different letter differ (P < 0.05).
between cows fed either extruded soybeans or rolled sunflower seeds. Kennelly and Khorasani
(1992) found no difference in milk yield and milk fat when cows were fed no flaxseed or up to
15% of the total DM as flaxseed although flaxseed decreased milk protein. In another
experiment, however, the same authors (Khorasani and Kennelly 1994) observed a decrease in
DM intake and milk yield when whole flaxseed was fed at 10% of the total DM. In this last
experiment, flaxseed feeding produced relatively small changes in the concentration of C18:3 in
milk, indicating that extensive biohydrogenation of PUFA occurred in the rumen, thus probably
depressing fibre digestion and feed intake.
Protein concentration in milk was higher for cows fed FLAX than for those fed MEGA (Table 3),
which disagrees with the decrease observed by Kennelly and Khorasani (1992). Protein
concentration is usually lower for cows supplemented with Ca long-chain FA such as Megalac®
(Shaver 1990) although Schingoethe et al. (1996) found a trend (P = 0.06) for higher protein
concentration whencows were fed sunflower seeds compared with when they were fed extruded
soybeans. A depression in milk protein concentration is frequently associated with dietary lipid
supplementation; however, daily protein production may be unchanged as supplemental fat
tends to have a positive effect on milk yield (Kennelly 1996). The formaldehyde treatment
applied to flaxseed could have prevented ruminal protein degradability and increased the amount
of protein secreted in milk. Milk lactose percentage was not affected by the diet. Daily yield of fat
was higher for cows fed MEGA than for those fed FLAX, which reflects the greater milk
production and fat percentage (P = 0.06) for cows fed MEGA. There was no difference between
diets in yield of protein and lactose. Milk somatic cell count was similar for both diets, as

previously reported for cows fed either extruded soybeans or rolled sunflowers as dietary fat
sources (Shaver 1990).
Milk fatty acid concentrations (Table 4) of C8:0, C10:0, C12:0, C14:0, C14:1, C18:0, C18:3, and
C20:5 were higher
for cows fed FLAX than for those fed MEGA while the inverse was observed for C16:0, C16:1,
C18:1, and C18:2. Protection of canola seed with aldehyde also decreased the proportion of C16:0
and increased that of C18 FA (Ashes et al. 1992). In general, modification of milk FA concentra-
tions were similar to those reported for cows fed up to 15% of flaxseed in the total DM (Kennelly
and Khorasani 1992). Grundy and Denke (1990) reported that C16:0 and C18:0 mono- and PUFA
elevate and lower, respectively, serum cholesterol in humans. Cows fed FLAX would, therefore,
produce milk to better meet human requirements for food leading to decreased blood
cholesterol concentrations. There was no difference between treatments for C18 total, but the
C16:0 to C18 total ratio was greater for cows fed MEGA. Concentrations of short-chain FA were
higher for cows fed FLAX and medium-chain FA concentrations were lower than for cows fed
MEGA. There was no difference in long-chain FA concentrations between cows fed MEGA and
FLAX. Individual short- and medium-chain FA (C14:0, C16:0, and C16:1) concentrations in blood
decreased from week 9 to week 19 of lactation, while there was a general increase in long-chain
FA concentrations (Table 5).
Fatty acid composition of milk and blood would mainly reflect influences of the diet. For instance,
the increase from week 9 to week 19 of lactation would result from an increase in dietary fat
content as cows fed supplemental dietary fat have a greater proportion of long-chain FA than
unsupplemented cows (Shaver 1990). Cows fed FLAX had lower C16:0 concentration than those
fed MEGA. There was a significant interaction (P < 0.05) between week and diet for C18:0 and
C18:2 with a decrease in C18:0 blood concentration for cows fed MEGA and an increase for
those fed FLAX between weeks 9 and 19, while the inverse was observed for C18:2.
Concentration of C18:1 was similar for both treatments. Concentrations of C18:3 and C18 total
were higher during week 19 than during week 9 of lactation, and they were higher for cows fed
FLAX than for those fed MEGA. Feeding flax increases the proportion of linolenic acid in milk fat
(Kennelly 1996). The C16:0 to C18 total ratio was higher during week 9 than week 19, and it was
higher for cows fed MEGA than for those fed FLAX.
Concentration of plasma non-esterified FA increased from week 9 to week 19 for cows fed
MEGA, whereas it remained similar for those fed FLAX, resulting in a significant interaction
between week and diet (Table 5). Greater non-esterified FA concentration is related to increased
body fat mobilization (Roberts et al. 1981), suggesting that increased fat mobilization could
have contributed to increase milk yield when cows were fed MEGA compared with when they
were fed FLAX (Table 3). There was a trend (P = 0.12) for an interaction between week and fat for
blood

Table 4. Milk fatty acid composition of Holstein cows fed between weeks 9 and 19 of lactation a
total mixed diet containing Megalac® and flaxseed meal (MEGA) or formaldehyde-treated
whole flaxseed (FLAX)z
Table 5. Blood composition of Holstein cows fed between weeks 9 and 19 of lactation a total mixed
diet containing Megalac® and flaxseed meal

zLeast squares means with pooled standard error (SE).
yFat  week interaction (P < 0.05).
xWeek effect (P < 0.05).
wFat effect (P < 0.05).
a–c Means within a row with a different letters differ (P < 0.05).
glucose concentration as a result of greater increase in glucose concentration between week 9
and week 19 for cows fed MEGA compared with those fed FLAX. Greater non- esterified FA and
lower glucose concentrations in blood are associated with greater negative energy balance
(Bauman and Currie 1980). Milk production was greater for cows fed MEGA than for those fed
FLAX although DM intake was similar, suggesting greater negative energy balance for the former.
As greater negative energy balance is associated with reduced reproductive performance (Spicer
et al. 1990), this could partly explain the lower conception rate for cows fed MEGA compared with
those fed FLAX in the present experiment. Lower glucose concentration is also related to lower
ruminal protein degradability (Garcia-Bojalil et al. 1998), which would further support the
efficacy of formaldehyde to protect flaxseed protein against the attack of rumen microbes.
According to Spicer et al. (1993), insulin is a powerful stimulator of follicular cell development.
However, in the present experiment, it is unlikely that insulin was the only factor involved in
follicle development as cows fed MEGA and FLAX had similar plasma insulin concentration.Plasma
concentrations of total and HDL cholesterol increased from week 9 to week 19 of lactation, but
the increase was greater for cows fed MEGA than for those fed FLAX, whichresult- ed in a
significant interaction between week and diet. Fat supplementation is known to increase blood
cholesterol (Spicer et al. 1993; Garcia-Bojalil et al. 1998), which would explain the increase
observed in the present experiment from week 9 to week 19 as cows began to receive fat from
week 9. Moreover, the greater increase in blood cholesterol for cows fed MEGA compared with
those fed FLAX corroborate the depressing effect of omega-3 FA as supplied by flax on blood
cholesterol already reported in humans (Cunnane 1995). Concentration of LDL cholesterol was
greater in week 19 than week 9 of lactation and it was greater for cows fed MEGA than for those
fed FLAX.
It has been suggested that improved conception rate could be a result of increased concentrations
in plasma cholesterol (Spicer et al. 1993), although this hypothesis was not sup- ported by the
results of the present experiment. In fact, cows fed FLAX had lower plasma cholesterol
concentration anda better conception rate than those fed MEGA. Other studies have reported no
relationship between cholesterol concentrations in blood and reproductive measures (Ferguson
et al. 1990; Spicer et al. 1990).
Length of estrous cycle was similar for the two diets (Table 6). Conception rates were
significantly higher for cows fed FLAX (87.5%) than for those fed MEGA (50.0%). There was no
effect of diet on the diameter of the largest and second largest follicules, or on the difference in
diameter between the largest and second largest follicle. Furthermore, there was no effect of diet
on the number of class 1, 2, and 3 follicles. However, the total number of follicles tended (P =
0.09) to be greater for cows fed MEGA than for those fed FLAX. The CL was similar for cows fed
MEGA and those fed FLAX. The area under the curve for milk progesterone concentration
tended (P = 0.14) to be greater for cows fed FLAX than for those fed MEGA.
Better conception rate for cows fed FLAX comparedwith those fed MEGA could result from
different prostaglandin synthesis. In fact, linolenic acid in flaxseed uses the eicosapentaenoic
acid metabolic pathway while FA in MEGA uses the arachidonic acid pathway (Cunnane 1995) and
it is known that eicosapentaenoic acid inhibits prostaglandin synthesis (Spicer et al. 1993).
Therefore, ingestion of linolenic acid contained in flaxseed could potentially inhibit PGF2

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