1. Individual fatty acid measurements in milk from Danish dairy cows
Lars Peter Sørensen & Lisa Hein
April 27, 2017
Nordic Workshop in Dairy Cattle Genomics

2. Outline Fatty acids in milk – what are they?
Why are fatty acids interesting?
Presentation of Danish fatty acid data
Genetics of fatty acids in milk
What is planned?

3. What are fatty acids? Defined by: Carbon chain length
Number of double bonds
Saturated
Unsaturated
Monounsaturated (MUFA)
Polyunsaturated (PUFA)
Configuration of double bond
Cis fatty acids
Trans fatty acids

4. Origin of fatty acids in milk
Directly and chemically unchanged from feed
From feed after ruminal biohydrogention
From mammary de novo synthesis
Mobilized fatty acids from adipose tissue
From feed or adipose tissue after mammary desaturation

5. Fatty acids and cow management
Especially long chain fatty acids (C16-C18) are affected by feed
Strong weight loss: increased proportion of oleic acid (18:1) - in some cases also palmitoleic acid (16:1)
Acidosis (SARA) results in more odd numbered fatty acids (C11, C13, C15, C17)
Trans fatty acids may indicate bad ruminal environment

6. Danish fatty acid data 10+ million milk samples since May 2015
Via routine recording scheme
Analysed using MIR spectroscopy
Fatty acid predicted using Foss Application Note 64
11 categories (7 groups and 4 individual fatty acids)

7. FOSS Application 64 Fatty acid group Name SFA Saturated fatty acids
C4 – C20
MUFA
Monounsaturated fatty acids
C18:1 (C16:1, C14:1)
PUFA
Polyunsaturated fatty acids
LA. ALA, CLA
SCFA
Short-chain fatty acids
C4-C10
MCFA
Medium-chain fatty acids
C12-C16
LCFA
Long-chain fatty acids
C18 -
TransFA
Trans fatty acids
C18:1tr, CLA
C14:0
Myristic acid
C16:0
Palmitic acid
C18:0
Stearic acid
C18:1
Oleic acid

8. Fatty acids and human health
68.5 %
27.5 %
4.0 %
43.1 %
39.0 %
11.5 %
3.5 %
11.1 %
29.6 %
11.4 %
24.1 %

9. Effect of breed on milk fatty acid compostion

10. Effect of production system

11. Large seasonal effect

12. Effect of lactation stage, Holstein
DIM

13. New markets? 40-50 dairy farms Increased payment, 8 c/l
SFA < 69 % of total fat
6 % less SFA
Holstein: 68.5 % SFA
6 % less = g SFA / l

14. Fatty acid genetics Time period: May 2015 to October 2016
Model: animal repeatability model DIM
Anmials: 1. parity Holstein (n=132,732) and Jersey (n = 21,966)
Observations: Holstein (n=611,055) and Jersey (n=95,920)
Genetic parameters, heritabilities and genetic correlations
Breeding values on bulls
Correlations between NTM breeding values

15. Heritabilities, Holstein
Fatty acid group
% of total
Amount, gram
SFA
0.15
0.19
MUFA
0.11
PUFA
0.08
0.09
SCFA
0.16
MCFA
0.12
0.20
LCFA
TransFA
0.07
0.06
C14:0
0.17
C16:0
0.14
C18:0
C18:1
0.13

16. Heritabilities, Jersey
Fatty acid group
% of total
Amount, gram
SFA
0.10
0.15
MUFA
0.09
PUFA
0.11
SCFA
0.16
MCFA
0.12
LCFA
TransFA
0.07
0.06
C14:0
0.13
C16:0
C18:0
C18:1

17. Genetic and phenotypic correlations
% of total fat
MUFA
PUFA
SCFA
C16:0
Total fat DH -
0.39
-0.70
-0.73
-0.08
0.61
-0.04
-0.51
-0.07
-0.69
-0.05
0.24
0.15
-0.64
-0.65
0.04
-0.33
-0.26
0.33
0.17 DJ
0.45
-0.57
-0.75
0.50
-0.02
0.52
0.13
0.14
-0.77
-0.29
-0.03
-0.11
0.10
rg below diagonal
rp above diagonal

18. Genetic variation – bulls with most daugthers in data set
NTM
C16:0 13
136 10
115
114 8 89 7 75

19. Correlations, NTM traits
Total fat, g
MUFA,%
PUFA, %
SCFA, %
C16:0, %
YLDD
0.88
-0.13
-0.07
0.16
MILK
0.39
0.26
0.15
-0.14
-0.12
PROT
0.65
0.10
0.11
-0.16
FATT -
-0.35
-0.27
0.32
GWTH
0.17
0.09
-0.09
FERT
-0.19
MAST
-0.10
HLTH
0.08
UDDR
-0.32

20. Future research on fatty acids
SOBcows – specialized Organic Breeding Goals and Breeding Schemes for Dairy cattle:

21. Future research on fatty acids
MAF project: Better decisions by using the fatty acid composition of milk (2017)
Information about improper feeding
Information about cow health
Information about cow fertility
Information about physical properties of milk