Estimation of heritability and genetic correlations for the major fatty acids in bovine milk

The current cattle selection program for dairy cattle
in the Walloon region of Belgium does not consider the
relative content of the different fatty acids (FA) in milk.
However, interest by the local dairy industry in differentiated
milk products is increasing. Therefore, farmers
may be interested in selecting their animals based
on the fat composition. The aim of this study was to
evaluate the feasibility of genetic selection to improve
the nutritional quality of bovine milk fat. The heritabilities
and correlations among milk yield, fat, protein,
and major FA contents in milk were estimated. Heritabilities
for FA in milk and fat ranged from 5 to 38%.
The genetic correlations estimated among FA reflected
the common origin of several groups of FA. Given these
results, an index including FA contents with the similar
metabolic process of production in the mammary gland
could be used, for example, to increase the monounsaturated
and conjugated fatty acids in milk. Moreover,
the genetic correlations between the percentage of fat
and the content of C14:0, C12:0, C16:0, and C18:0 in
fat were −0.06, 0.55, 0.60, and 0.84, respectively. This
result demonstrates that an increase in fat content is
not directly correlated with undesirable changes in FA
profile in milk for human health. Based on the obtained
genetic parameters, a future selection program to improve
the FA composition of milk fat could be initiated.