3. Friday - Ruminant Sessions prof adam lock michigan state university - rumen health & milk fat depression

2018 © Board of Trustees of Michigan State University
Rumen Health and Milk Fat Depression
Feedworks 2018 Conference
Performance Through Science
Twin Waters Resort
Queensland, Australia
September 19-21, 2018
Adam L. Lock
Department of Animal Science
Michigan State University

Milk Fat Seasonal Variation in Australia
Data Supplied by Dairy Australia
3.60
3.80
4.00
4.20
4.40
4.60
4.80
2011 2012 2013 2014 2015 2016
MilkFatContent(%)
Year
DairyNSW
GippsDairy
Murray Dairy
WestVic
3.60
3.80
4.00
4.20
4.40
4.60
4.80
January
February
M
arch
April
M
ay
June
July
AugustSeptem
ber
OctoberNovem
berDecem
ber
MilkFatContent(%)
Month
3.60
3.80
4.00
4.20
4.40
2011 2012 2013 2014 2015 2016
MilkFatContent(%)
Year
DairyNSW
GippsDairy
Murray Dairy
WestVic

Annual Seasonal Challenges with Milk Fat
• Annual rhythm of milk component content (and yield) varies by
geographical location and herd
• Each herd and each cow is somewhere on a continuum
• Important to monitor milk components:
- Allow for predicting future concentrations and yields of milk components that
may be produced (managing expectations)
- Provide benchmarking for determining whether a change in components is to
be expected or it is an acute nutrition/management issue (e.g. milk fat
depression)

WHEN THE COWS DROP IN
MILK FAT

Milk Fat Depression
• Milk fat reduced but milk
yield and other milk
components unaffected
• It is not an overt rumen
dysfunction reducing
fiber digestion and
acetate yield
• Caused by bioactive FA
and NOT by limitations in
substrate supply
• This is a common cause
of reduced milk fat yield,
but is not meant to
explain every change in
milk fat

Some Points of Consideration
• When milk fat is acceptable
- Inclusion of risk factors acceptable and
may be advantageous to production and
efficiency
• When milk fat is low: look for a reason
- When did it start and what happened ~7-10 d prior?
- Is it a certain string or group of cows?
High Producing cows likely more susceptible
- What season is it?
- Is the sample a daily average?

Fats in plants are primarily unsaturated -
Ruminant fats are saturated
 Unsaturated FA are Toxic to Rumen Bacteria
Biohydrogenation

Mechanism for Diet-Induced MFD
• Increased duodenal flow of specific BH intermediates (CLAmfd)
- Increased passage rate
- Intermediates flow out of the rumen before complete BH
• Changes in rumen environment
- Change in microbial populations
 Shift in BH pathways and intermediates produced
 Slower less complete BH
• Specific action at mammary gland
• Biohydrogenation theory

• Low milk fat is typically not
caused by a single factor on
farm
• We can not eliminate all risk
factors
• We probably do not want to
eliminate all risk factors
Nutrition
Environment
Management
Physiological
State
Milk
Fat
Many Factors Cause MFD

Bottom Line for Both
Minimizing Risk and
Correcting a Low Milk Fat
Situation?
Understanding
& controlling BH
pathways &
formation of
specific BH
intermediates

‘Dose’ Dependent Response
• The extent of MFD is directly related
to amount of CLAmfd leaving the
rumen and taken up by the MG
• Magnitude of decrease in milk fat
(e.g. 4.0 to 3.6%) could be caused by
as little as 1 to 2 g/d (< 0.02% dietary
DM) of CLAmfd passing to the SI
-60
-50
-40
-30
-20
-10
0
0 3 6 9 12 15
PercentageChangeinMilkFatYield
Dose trans-10, cis -12 CLA (g/d)
(Abomasal infusion of CLA – 7 studies)
de Veth et al. (2004)

Timeline for Milk Fat Depression
• Key Questions:
- When MFD occurs… when did the problem originate?
- When correcting the diet… when do we expect to see improvements?
• Following a dietary adjustment:
- A lag of 7 to 10 days is expected to see MFD
• Following a diet correction:
- It will take 10 to 14 days to rescue milk fat synthesis (but should start
to see a movement by 7 days)

Excessive
Unsaturated FA Intake
Low pH
Excess Rapidly
Degradable CHO
Rumen Conditions That
Increase CLAmfd Intermediates?

• Characterised by lots of lush (low peNDF) pasture /
ryegrass with high digestibility
- Fast rumen throughput?
• Pasture has high FA content (up to and over 6%)
- Lots of rumen available PUFA
• Generally associated with feeding large amounts > 3
kg slugs of fast fermenting grains (> 6kg/cow/day)
- Altered rumen fermentation/reduced rumen pH
Primary Risk Factors for MFD in a Pasture-Fed Situation

Pasture Fat Contents
(67 herds, Spring 2001 samples) (Bramley et al 2002)

Fatty Acid Composition of Australian Pastures
Based on 45 samples provided by Rawnsley et al. (University of Tasmania) for FA analysis
0.00
0.50
1.00
1.50
2.00
2.50
3.00
C16:0 C18:0 C18:1 C18:2 C18:3 Total
FA,%DM
Fatty Acid Content (% DM)
21
2
2
11
53
Fatty Acid Profile (g/100 g FA)
C16:0 C18:0 C18:1 C18:2 C18:3

Fatty Acid Composition of Australian Pastures
1.50
1.70
1.90
2.10
2.30
2.50
2.70
LF1 LF2 LF3
TotalFA,%DM
P<0.01
0.00
0.50
1.00
1.50
2.00
2.50
0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00IndividualFA,%DM
Total FA, % DM
C18:3 C18:2 C16:0

Ether Extract vs. FA Content of Australian Pastures
y = 0.67x - 0.07
R² = 0.93
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00
FA,%DM
Ether Extract, % DM

Ether Extract Content of Australian Pastures
Based on results from 270 samples collected and analysed by Rawnsley et al. (University of Tasmania)
3.70
3.90
4.10
4.30
4.50
LF1 LF2 LF3
EtherExtract,%DM
P<0.01

Ether Extract Content of Australian Pastures
3.70
3.90
4.10
4.30
4.50
D-0 D-1.5 D-3.0
EtherExtract,%DM
Nitrogen dose (kg/d)
P<0.01
Based on results from 270 samples collected and analysed by Rawnsley et al. (University of Tasmania)

Effects of Nitrogen Application on C18:3
Content of Pastures
Morgan et al. 2014. Grassland Science in
Europe, Vol. 19 pp. 550
Elgersma et al. 2007. in Fresh Herbage for
Dairy Cattle. pp 175–194

Practical Implication for Pasture Management
• The correct point to graze in order to limit FA intake coincides with what is
generally regarded as the correct point of grazing for optimal agronomic
outcomes (LF3)
• Poorly managed grazing rotations with early entry at low leaf emergence,
coupled with nitrogen use to promote growth, is more likely to produce
greater FA content of plant tissue (and greater FA intakes)
• This increased FA content/intake at sub optimal grazing points will be
compounded by lack of effective fiber at these leaf emergence points

Rumen Environment
• Factors that alter rumen environment are
traditionally first considered when
troubleshooting MFD on dairy farms
• Ruminal pH is a determinant of microbial
populations in the rumen
- Low ruminal pH is one major factor that can lead to a
change in rumen BH pathways
• Changes in rumen pH are most likely associated
with MFD because they cause a change in the
bacterial population favoring those that have
alternative BH pathways
• Clinical acidosis (even SARA) is NOT a prerequisite
for MFD to occur; subtle ruminal changes are all
that are required (e.g. pH 6.2 down to 5.8)
Allen. 1997. J. Dairy Sci. 80:1447

Effect of pH on Biohydrogenation
3. Inhibit final step/
alter rates of BH
Linoleic acid
(cis-9, cis-12 18:2)
Rumenic acid
(cis-9, trans-11 CLA)
Vaccenic acid
(trans-11 18:1)
Stearic acid
(18:0)
trans-10, cis-12 CLA
trans-10 18:1
Stearic acid
(18:0)
1. Increase C18 UFA Precursors
2. Alter BH pathways/rumen
environment

y = 0.10x - 0.07
R² = 0.99
y = 0.04x - 0.02
R² = 0.99
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0% 1% 2%
pH 5.8
y = 0.64x + 0.44
R² = 0.96
y = 0.38x + 0.20
R² = 0.99
0.0
0.5
1.0
1.5
2.0
2.5
0% 1% 2%
pH 5.8 pH 6.2
trans-10, cis-12 18:2
g/100gFA
g/100gFA
trans-10 18:1
OIL concentration
(24 hr Results)
OIL concentration
At 24 hr:
• Culture pH X OIL interaction for trans-10, cis-12 18:2, P < 0.05
• Culture pH X OIL interaction for trans-10 18:1, P < 0.005
pH & Corn Oil Interactions
Sun et al. 2014. J. Dairy Sci. 97 (E-Suppl. 1): 319

Fermentation Rates of Starch Sources
• Careful consideration should be given to the fermentation rate of starch
sources when troubleshooting MFD issues
- Grain Source
Wheat > Barley > HMC > Dry Corn
- Moisture
High moisture > Dry
- Processing
Steam flake > Fine ground > Coarse ground > Cracked > Whole

Altering the Main Source of Dietary Carbohydrate
2.9
3.0
3.1
3.2
3.3
3.4
3.5
3.6
Corn Oats Barley Wheat
MilkFatContent(%)
Main Source of Carbohydrate
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
Corn Oats Barley Wheat
MilkFatYield(kg/d)
Main Source of Carbohydrate
a
ab
b b
a
ab ab
b
Gozho & Mutsvangwa. 2008. J Dairy Sci. 91:2726–2735

• 33% SC increased CLA
by 20%
Starch Content
• No main effect of SF
Starch
Fermentability
• pH 5.8 increased CLA
by 67%
Culture pH
trans-10, cis-12 CLA
0.00
0.05
0.10
0.15
0.20
0.25
22% SC 33% SC
22% SC
33% SC
trans-10,cis-12CLA,g/100totalFA
**
0.00
0.05
0.10
0.15
0.20
0.25
pH 6.2 pH 5.8
pH 6.2
pH 5.8
**
(**P < 0.001)
0.00
0.05
0.10
0.15
0.20
0.25
DC HMC
DC
HMC
P = 0.13
Yan, Allen, & Lock, ADSA-ASAS Annual Meeting, 2015

Saccharomyces Cerevisiae Fermentation Product
• Saccharomyces cerevisiae fermentation product (SCFP) prevented MFD
during 2-d fermentable starch challenge
(Longuski et al., 2009)
(Williams, et al., 1991; Miller-Webster et al., 2002)
• Potential mechanisms:
- Changes metabolism of ruminal microbes and stabilized rumen
fermentation

trans-10, cis-12 18:2 – 24 h
0.2
0.3
0.4
0.5
0.6
CON SCFP
trans-10,cis-1218:2,g/100gtotalFA
• A-RF decreased trans-
10, cis-12 18:2 by 17%
(P < 0.01)
Rumen fluid
0.2
0.3
0.4
0.5
0.6
pH 5.8 pH 6.2
• pH 5.8 increased
trans-10, cis-12 18:2 by
56% (P < 0.01)
Culture pH
0.2
0.3
0.4
0.5
0.6
HMC DC
• HMC increased trans-
10, cis-12 18:2 by 15%
(P < 0.05)
Starch
fermentability
U-RF A-RF

0.0
0.1
0.2
0.3
0.4
0.5
0.6
CON SCFP
DC HMCtrans-10,cis-1218:2,g/100gtotal
FA
Rumen fluid
type
• Rumen fluid × starch fermentability interaction (P < 0.01)
Rumen Fluid × Starch Fermentability – 24 h
U-RF A-RF
1.0
1.2
1.4
1.6
CON YC
DC HMC
Milkfatyield,kg/d
(Longuski et al., 2009)
SCFPCON SCFPU-RF A-RF

2.0
2.5
3.0
3.5
4.0
Low Starch High Starch
MilkFat%
Starch Starch-Monensin Starch-Oil Starch-Monensin-Oil
Monensin and MFD
Interaction Between Unsaturated FA, Starch, and Monensin
2.0
2.5
3.0
3.5
4.0
0 1.7 3.4
MilkFat%
Supplemental Soybean Oil (% DM)
No MN MN (22 mg/kg DM)
Van Amburgh et al. 2008. Cornell Nutrition ConferenceAlzahal et al. 2008. J Dairy Sci. 91:1166–1174

Management Factors Associated
with Reduced Milk Fat
• Feeding frequency
• Mixing
• Sorting
• Slug feeding
• Stocking density
Rumen environment is critical to milk fat yield and involves interactions
of numerous dietary, cow, and environmental factors

What Can We Do to Avoid MFD and/or
Troubleshoot Low Milk Fat?
• High unsaturated FA load diets are to be expected
- We can not control PUFA intake (rather, very hard to control)
- However, knowing variation and what is actually being fed important
 Unexpected changes
 Minimizing variation
• Must take opportunities to reduce fermentability of the diet to avoid shifts in BH
and increased production of CLAmfd
- Reduce starch fermentability and/or slug feeding
 Consider using corn (or other less fermentable starch sources) to replace some or all of
wheat (depending on feed rates)
- Consider increasing peNDF of the diet
- Consider choice of rumen modifier(s)
• Interactions!

Correcting Milk Fat Depression
Unsaturated Fatty Acids vs Diet Fermentability
• Under TMR situations we typically consider that:
- Dietary UFA are the most important factor to correct first
- Correcting fermentability also very important and can provide an additional
benefit (some concern with lost milk)
 I think doing both is the best approach when correcting MFD
• Under typical pasture situations:
- Much harder to correct UFA, especially from pasture
o But can we consider other sources of UFA in the diet (by products, fat
supplements etc), pasture growth stage when fed
- Correcting fermentability likely provides many more opportunities
o Starch sources, rates of feeding, peNDF, pasture growth stage when fed

• MFD is caused by unique fatty acids (CLAmfd) originating from ruminal
biohydrogenation
• Rumen environment is critical and involves interactions of numerous dietary,
cow, and environmental factors
• Induction occurs in ~7 to 10 d and recovery requires longer (~10 to 18 d)
depending on the severity of MFD and the dietary changes made to remedy
• Unsaturated FA intake and diet fermentability are the primary issues to consider
• When seeking to boost milk components, focus on nutrition, but must not forget
the feeding environment & management
• Management that alters natural feeding, resting, or ruminating behavior can
alter milk fat even when the diet is properly formulated
• Vital to benchmark: monitor milk yield and milk fat over time

http://dairynutrition.msu.edu
https://www.facebook.com/MSUDairyNutritionProgram
allock@msu.edu

2018 © Board of Trustees of Michigan State University.
All Rights Reserved. No part of this presentation may be
recorded, transmitted, or modified in any form or by
electronic, mechanical, or other means without the
written permission of Michigan State University.
Contact Details:
Dr Adam L. Lock
Department of Animal Science
Michigan State University
allock@msu.edu
517-802-8124

Resolving a MFD Issue (Avoiding a MFD Issue)
• Dietary FA
- Concentration of C18:2
most important (also
consider other UFA)
- Sources of C18:2 (rate of
release/availability)
• Reduce diet PUFA
- Least risk of losing milk in
the short-term
- Replace unsaturated FA
with saturated FA
supplements (not all are
the same)
• Diet Fermentability
(rumen pH)
- Consider carbohydrate
profiles and effective fiber
- Increase forage NDF and
effective fiber
- Switch rapidly
fermentable sources for
less rapidly fermentable
sources
- Reduce starch and
increase fiber
 Experience with similar
diets in your area is
important
 Cognizant of lost milk?
• Feeding Strategies
- Number of feeding
times per day
- Stocking density
- Slug feeding
- Feeding times

• Milk fat production makes up the major
‘energetic investment’ of milk synthesis,
accounting for over one-half of the energy
needed
• During MFD  priority for milk
production,  priority for storage of
energy as adipose (Van Soest, 1963)
• 0.25 percentage unit reduction in milk fat
concentration results in ~ 3% reduction in
milk energy output (assuming no change
in milk yield)
Milk Fat & Energy Partitioning
670
680
690
700
710
720
730
180 200 220 240 260 280 300
BodyWeight,kg
Days in Milk
2.8
3.0
3.2
3.4
3.6
3.8
180 200 220 240 260 280 300
BodyConditionScore,pt
Days in Milk
670
680
690
700
710
720
730
180 200 220 240 260 280 300
BodyWeight,kg
Daysin Milk
0.2%difference 0.4%difference 0.6%difference

0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
CON DV
5.8-DC 5.8-HMC
6.2-DC 6.2-HMC
Rumen fluid type
U-RF A-RF
Rumen fluid × culture pH ×
starch fermentability (P < 0.01)
Rumen Fluid × Culture pH × Starch Fermentability
U-RFCON SCFPU-RF
At low culture pH
(pH 5.8)
A-RF
• Rumen fluid adapted to SCFP (A-RF) decreased concentration of trans-10,
cis-12 18:2, especially at low culture pH and high starch fermentability

3. Friday - Ruminant Sessions prof adam lock michigan state university - rumen health & milk fat depression

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