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

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?

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

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

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

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)

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

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 %

Effect of breed on milk fatty acid compostion

Effect of production system

Large seasonal effect

Effect of lactation stage, Holstein DIM

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 = 0.730 g SFA / l

Fatty acid genetics Time period: May 2015 to October 2016 Model: animal repeatability model 8-305 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

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

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

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

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

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

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

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