Genetic Parameters for Major Milk Fatty Acids and Milk Production Traits of Dutch Holstein-Friesians

Abstract

The objective of this study was to estimate genetic parameters for major milk fatty acids and milk production traits. One morning milk sample was collected from 1,918 Holstein-Friesian heifers located in 398 commercial herds in The Netherlands. Each sample was analyzed for total percentages of fat and protein, and for detailed fatty acid percentages (computed as fatty acid weight as a proportion of total fat weight). Intraherd heritabilities were high for C4:0 to C16:0, ranging from 0.42 for C4:0 to 0.71 for C10:0. Saturated and unsaturated C18 fatty acids had intraherd heritability estimates of approximately 0.25, except for C18:2 cis-9, trans-11, which was 0.42. Standard errors of the heritabilities were between 0.07 and 0.12. Genetic correlations were high and positive among C4:0 to C14:0, as well as among unsaturated C18, but correlations of C4:0 to C14:0 with unsaturated C18 were generally weak. The genetic correlation of C16:0 with fat percentage was positive (0.65), implying that selection for fat percentage should result in a correlated increase of C16:0, whereas unsaturated C18 fatty acids decreased with increasing fat percentage (-0.74). Milk fat composition can be changed by means of selective breeding, which offers opportunities to meet consumer demands regarding health and technological aspects.

Genetic variability of milk fatty acids

“…Karijord et al (1982) found a lower value, equal to 0.09. Stoop et al (2008) as Renner and Kosmack (1974a) suggested a relation between FA length and the heritability estimates. The other cited studies did not observe the same trend.…”

“…Further, this model permits to take into account the performances of ancestors, descendants and collateral relatives, and thus improves the accuracy of the estimation. More recent studies, such as Soyeurt et al (2007a and2008b), Stoop et al (2008) and Bobe et al (2008), used an animal model to estimate the genetic parameters of FAs.…”

“…These differences could be explained mainly by the data (the second data set contained spectral data from a larger number of winter milk samples) and partly by the improvements of the calibration equations (78 reference milk samples used to build the calibration equations instead of 49 used in the previous study). Stoop et al (2008) used a single-trait animal mixed model to calculate the heritability of the individual FA measured by gas chromatography and expressed as %wt (FA weight as a proportion of total fat weight), based on 1918 milk samples collected from 1918 cows between February and March 2005. The benefit of using gas chromatography instead of mid-infrared spectrometry is a more accurate measurement of FAs with low concentrations in bovine milk fat.…”

“…In fact, if the concentration of an individual FA in bovine milk decreases, the accuracy of its prediction by mid-infrared spectrometry decreases (Soyeurt et al 2006a). Stoop et al (2008) studied a large number of various FAs, especially of several isomers of C18:1. The various studied isomers showed similar heritabilities, ranging between 0.11 and 0.18.…”

Validation of fatty acid predictions in milk using mid-infrared spectrometry across cattle breeds

“…Milk fat composition varies with both environmental factors (e.g. feed regime; Palmquist, 2006) and genetics (Soyeurt and Gengler, 2008;Stoop et al, 2008). Changing FA composition through the feed regime or genetic selection requires a precise and regular measurement.…”