Factors affecting milk quality & production

Factors affecting milk quality
and quantity
Prem Agarwal 2019-V-66

Introduction
Milk Production 187.75 Million tonnes in 2019 (6.5% more than last year)
Variation in Composition and Yield of Milk is a regular phenomenon in any
milking animals.
Factors
Physiological –
Genetic Makeup, Age, Pregnancy
etc.
Environmental –
Climate, Nutrition, Management,
etc.

Factors Affecting Milk Quantity & Quality
• Species
• Breed
• Age
• Stage of lactation
• Estrus
• Dry period
• Pregnancy
• Seasonal difference
• Maintanance conditions
• Nutritional Factors
• Feed and water supply
• Milking intervals
• Milking frequency
• Diseases
• Feed
• Disease
• Geographical location
• Stress
• Microbiological count
• Other management factors…

Buffalo
I-35% ND-
14%
Cow
I-10% ND-11%
CB-26% E-1%
Goats
3%
Yak, Camel,
and other
animals
Species

Breed
Highest Producing Indigenous Cow
Highest Producing Buffalo Breed
Cow Breed with Highest Fat %
Cow Breed with Lowest Fat %
Dual Purpose Milch Breed Cross Breed Exotic Breed
The concentrations (%) of the three major milk constituents are genetically controlled to a
considerable extent. Heritiabilities of fat, protein, and lactose contents average 0.58,0.49,
and 0.5, respectively, while that of milk yield average 0.27.
Gir (Longest lactation), Sahiwal (Best Milch Breed)
Murrah (2200 L/lactation)
Jersey (7%), Sahiwal (5%)
Holstein Friesian (3.2%)

Age & Lactation Number (Parity)
The amount of milk increases with age due to two reasons
An increase in body weight, which results in a larger digestive system and
a larger mammary gland for the secretion of milk.
Recurring pregnancies and
lactation can result in
increases of 30 % in milk
production. Milk
production increases with
lactation number and is
maximized in the fourth or
the fifth lactation.

Pregnancy
Pregnancy has an inhibitory effect on milk yield. The inhibitory
effect of pregnancy is not likely due to fetal requirement. It is
believed that the increase in estrogen and progesterone levels
as pregnancy progresses, inhibits milk secretion.

Stage of Lactation

First mammary secretion after parturition
differs greatly from normal milk
Cow's colostrum contains more minerals,
protein and less lactose than milk.
Fat % is usually higher in colostrum than in milk.
Calcium, Mg, P, and Cl are high in colostrum,
whereas K is low. ( Iron is 10-17 times higher in
colostrum than in milk.
Colostrum contains 10 times as much vitamin A
and 3 times as much vitamin D as milk.
Changes in composition occur during the first
few days continue but at reduced rate for about
5 weeks of lactation.
Fat and protein % then rises gradually and may
increase more sharply near the end of lactation.
Lactose decreases while mineral concentration
increases slightly during that period.

Dry Period
 Dairy cows are dried-off for 2 months prior to the next calving. Rest
period is necessary to maximize milk production in subsequent lactation.
 Milk yield is usually reduced when the dry period is less than 40-60 days
(25-40% less milk). Dry period longer than 60 days in length does not
result in any significant increase in milk production
 Long dry periods decrease the average annual production of the cow by
extending the calving interval beyond the normal 13-14 month interval
Also causing a decrease in the lifetime production of the dairy cattle.
 Part of the dry period effect is related to body condition of the cow at
calving. Cows in good body condition at calving produce higher milk yield
during the following lactation than in cows in thin body condition at
calving.

Seasonal Differences
• Calving at Winter, Spring or Autumn is preferable not in Summer as it
decreases milk production. Calving schedule should be adjusted keeping this
in mind

In general, milk fat and solid-not-fat percentages are highest in winter and lowest in
summer. Milk fat and protein percentages are lower by 0.2-0.4% in summer than
winter.

Temperature & Humidity
No effect on milk production in Comfort Zone. Milk production declines when environmental temperature
exceeds 27 °C. The reduction in milk yield is largely due to drop in feed intake. High temperature affect high
producing cows more than low producers and it is particularly harmful during the peak of lactation.

Stress
Signs of Stress in Cattle
• Respiratory Issues - Sickness
• Standing While Other Cows Are Lying Down
• Frequent Urination
• Rapid Heart Rate – Adrenaline induced stress
• Trembling – Fear or Weather Stress
• Seeking out Shade – Heat Stress
• Open- Mouthed Breathing- Heat Stress
• Slobbering - Hypersalivation
• Lack of Coordination – Heat Stress
• Restlessness
• Splashing Water – Heat Stress
• Huddling Together – Cold Stress

STRESS
LH GH
Cortisol
Oxytocin
CA Prolactin
Reproductive Problems Reduced Growth
Immuno - supression
Milk ejection
Problems
Lactation Problems
Calving Problems
CA

Feed and Water Supply
 Inadequate feed nutrients probably limit the
secretion of milk
 Galactopoisis is closely related to an adequate
feed intake by the lactating animal.
 The most dramatic effect is brought about by
shortage of water as the cow has no means of
storing water.
 Withholding access to water, or insufficient
supply of water for few hours will result in a
rapid drop in milk yield..
Maintenance
Growth
Production

Finely chopped
forage
Less saliva
production
pH in Rumen ↓6
Reduced activity
of cellulolytic
bacteria
Milk Fat
Depression
Syndrome
Effect of Nutrition on Composition
Out of all milk components, milk fat is the most influenced by dietary
manipulations. Most of changes in milk composition due to dietary
manipulation are related to changes in ruminal acetate : propionate ratio.
Several nutritional factors can influence milk composition. These include
A. Plane of nutrition - Underfeeding ↓ Lactose % & ↑ Fat %, Energy :
Protein Ratio should be maintained
B. Forage : Concentrate ratio - ↑Conc. → ↓Fat %
C. Forage quality (e.g. particle size)
D. Level and type of dietary fat – PUFA → ↓Fat % (Biohydrogenation in
Rumen) Veg Oil → ↑Fat %

Milking Interval
• Cows are usually milked at equal intervals (12-h
interval for 2 x milking).
• Cows milked at unequal intervals produce less milk
than those milked at equal intervals.
• The reduction in milk yield is more in high
producing cows than in low producing ones.
The pressure measured in the teat cistern increases
in three phases.
1. An initial rapid increase in the pressure- residual
milk
2. The second- newly synthesized milk
3. The third phase is marked by an accelerated
pressure increase and probably represent
overfilling of alveoli, ducts and gland cisterns.

• Milking time for most
cows is 5-6 minutes per
cow.
• Milking should be done
rapidly and completely –
by Full hand method
then Stripping
• Incomplete milking permanently reduce milk yield for the
entire lactation. Residual milk decreases milk secretion due to
feedback inhibition and physical disruption.
•

Change in Milk Composition during Milking
• Milk fat % increases continuously during the milking process. First drawn milk
may contain only 1-2% fat, whereas, at the end of milking, fat % may be 5-10%.
• This is because of the tendency of the fat globules to cluster and be trapped in
the alveoli. Thus after incomplete milking, milk fat content will be lower than
normal.
• Residual milk (milk remains in the udder after milking) may contain up to 20%
fat.

Milking Frequency
Cows are usually milked twice daily.
Milking a twice a day yields at least 40% more milk than once a day.
The increase is usually highest for first lactation cow and declines as the cow gets older.
Reasons for increased milk production as frequency of milking increases are
1) Less intramammary pressure generated with frequent milking,
2) Increased stimulation of hormone activity favorable of milk production
3) Less negative feedback on the secretory cells due to the accumulation of milk components.
Increasing milking frequency to 3 x day increases milk yield byup to 20% (range 5-20%).
There are several problems associated with 3 x per day milking.
1) May increase the incidence of mastitis
2) Existing problems will be aggravated in poorly managed herds
3) More management cost

Disease
 The main disease that affect milk yield of dairy
cows is mastitis.
 It impairs the ability of secretory tissue
synthesize milk components and destroys the
secretory tissues and consequently lowering
milk yield.
 A decrease in production persists after the
disappearance of the clinical signs of mastitis
due to a destruction in the secretory tissues.
 In severe mastitis, the casein content may be
below the normal limit of 78% of total protein
and the chloride content may rise above the
normal maximum level of 0.12%.
 FMD, Tuberculosis, Brucellosis, Blue Tongue,
and Vesicular Stomatitis

Factors Affecting Microbiological quality of Milk
1. Endogenous sources, (the
cow itself)
2. Exogenous sources, such
as
i. environment (soil, water,
manure or human
contact)
ii. collection and processing
equipment
iii. human milk handlers on
the farm and in the
factory.

Somatic Cell Count
• One of the quality parameter of raw milk.
• High somatic cell counts (SCC) present in milk are the
main indicators of mammary gland infection, caused by
specific and non specific micro-organisms.
• An elevated SCC in milk has a negative influence on the
quality of raw milk, low production and shelf life.
Undesirable organoleptic characteristics and poor
yogurt fermentation is also seen.

Conclusion – The Way Forward

Factors affecting milk quality & production

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Editor's Notes