Genetic analysis of predicted fatty acid profiles of milk from Danish Holstein and Danish Jersey cattle populations

Abstract

The objective of this study was to assess the genetic variability of the detailed fatty acid (FA) profiles of Danish Holstein (DH) and Danish Jersey (DJ) cattle populations. We estimated genetic parameters for 11 FA or groups of FA in milk samples from the Danish milk control system between May 2015 and October 2016. Concentrations of different FA and FA groups in milk samples were measured by mid-infrared spectroscopy. Data used for parameter estimation were from 132,732 first-parity DH cows and 21,966 first-parity DJ cows. We found the highest heritabilities for test day measurements in both populations for short-chain FA (DH = 0.16; DJ = 0.16) and C16:0 (DH = 0.14; DJ = 0.16). In DH, the highest heritabilities were also found for saturated FA and monounsaturated FA (both populations: 0.15). Genetic correlations between the fatty acid traits showed large differences between DH and DJ for especially short-chain FA with the other FA traits measured. Furthermore, genetic correlations of total fat with monounsaturated FA, polyunsaturated FA, short-chain FA, and C16:0 differed markedly between DH and DJ populations. In conclusion, we found genetic variation in the mid-infrared spectroscopy-predicted FA and FA groups of the DH and DJ cattle populations. This finding opens the possibility of using genetic selection to change the FA profiles of dairy cattle.

Role of Fatty Acids in Milk Fat and the Influence of Selected Factors on Their Variability—A Review

“…Regarding phenotypic differences in individual FAs, variability is higher for UFA than for SFA ( Table 3 ). This is primarily related to the pathway of FA biosynthesis [ 121 , 122 , 123 ]. Most SFAs are synthesized de novo (in mammary epithelial cells); whereas, most UFAs are obtained from the diet and body fat stores [ 98 ].…”

“…The results were therefore somewhat limited; however, the studies did increase interest in the topic and over the last decade, especially, many follow-up studies have been published ( Table 4 ). Increasing interest in this topic was initiated by new findings in genetic research and developments in the methods for FA determination (i.e., increased speed and ease of use as well as reduced cost of FA analysis) [ 119 , 123 , 124 ].…”

“…Generally, heritability depends on FA saturation and on carbon numbers of the FAs ( Table 4 ). As such, heritability estimates are mostly higher for SFAs than for UFAs, and an increase in carbon number reflects a decrease in the heritability estimate (higher heritability for short- and medium-chain FAs than for long-chain FA groups) [ 123 , 124 , 129 , 130 ]. Consistently, these estimates correspond with the FA biosynthesis mechanism.…”

“…Overall, results for genetic correlations indicate that cows are genetically predisposed to produce more SFA when fat content increases [ 120 ]. On the other hand, fat content can be negatively correlated with UFA, suggesting selection for increased fat content will decrease these FAs [ 123 , 135 ] ( Table 5 ).…”

The evolving role of Fourier-transform mid-infrared spectroscopy in genetic improvement of dairy cattle

“…For individual milk fatty acids, heritability estimates ranged from 0.05 to 0.54 [9,53,54]. Heritability estimates for grouped fatty acids ranged from 0.11 to 0.51 [9,[55][56][57], with the lowest heritability estimates reported by Hein et al [55]. In the studies by Fleming et al [56] and Narayana et al [57], heritability estimates were consistently higher for saturated fat and short-and medium-chain fatty acid groups, compared to unsaturated fat and long-chain fatty acid groups.…”