Genetic parameters of the major fatty acid (FA) contents in cow milk

peer reviewedGenetic parameters were estimated for fractions of saturated, monounsaturated (MONO) FA, C12:0, C14:0, C16:0, C18:0, C18:1 and C18:2 9-cis, 12-cis in milk. 7,700 samples collected from April 2005 May 2006 were scanned by MilkoScan FT6000. The FA contents were predicted from spectral data. The final data set included the FA contents as well as milk yields, %fat and %protein for 40,007 records on 2,047 cows in 7 breeds . Analyzes were by a multi-trait model with effects herd *test date* lactation number, lactation stage*lactation number, age* lactation number, regression on breed fractions, permanent environments within and across lactations and animal effect. The heritabilities of FA ranged from 5 to 38 %. Heritability for SAT and MONO in milk were 36.28% and 14. 73%, respectively . The genetic correlations between C12:0 and C14:0, C16:0, C18:0, C18:1, C18:2 in milk were 0.94, 0.89,0.93, 0.53 and O.61, respectively. An indexincluding FA with a similar mammary origin could be used to modify the FA composition