Effect of genotype, lactation and climatic factors on fatty acid profile of bovine milk

Milk fat from bovine milk contains fatty acids that may have favourable properties for human health, for example, conjugated linoleic acid (CLA) has nutraceutical activity. This research aimed to know the effects of genotype, days of lactation and climatic factors on the fatty acids (FA) profile of milk and particularly the content of CLA in milk fat. Seventeen first-calving milking cows in early lactation were used for the assessment of milk; 12 were Gyr and five were F1 (Holstein/Gyr) crosses. Sampling was carried out every 15 days, from the beginning to the end of lactation (300 days). Fatty acids were analyzed employing gas chromatography. The genotype did not influence the content of the fatty acid groups: saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA) and CLA. The highest MUFA and PUFA contents were recorded at 100 days of lactation (32.334 and 3.553 g/100 g of FA, respectively), while SFA and CLA had their highest production at 200 days of lactation (63.238 and 1.378 g/100 g of FA, respectively). Regarding the climate, the highest temperature caused a decrease in the CLA content, because temperatures above 30 °C caused a decrease in the grazing time.