IMPACT OF LACTATION STAGE ON MILK FAT FATTY ACIDS PROFILE IN GRAZING DAIRY COWS

Abstract

The aim of the paper was to extend the knowledge about correlation of current fatty acids (FAs) profile of cow milk fat at herds of cows (n=134) at summer pasture period in mountain dairy farms in Slovakia to milk production and quality parameters. The FAs composition of individual milk was determined by GC-MS, where 54 FAs were identified. Saturated fatty acids (SAFA) (70.48 ± 4.04% in the milk fat) show in the first third of lactation highly significant positive correlation coefficients (r> 0.45, P <0.01) with all indicators of milk production (days, the total amount of milk fat and protein in kg). Monounsaturated fatty acids (MUFA) (26.26 ± 3.59%) have to the total milk production significant indirect relationship. Their content decreases with the rise of the total amount (kg) of produced fat (r=-0.426), protein (r=-0.494), milk (r=-0.514), and with the increasing number of days of lactation (r=-0.583, P <0.001). Polyunsaturated fatty acids (PUFA) (3.26 ± 0.069%) show negative correlation coefficients to total amount of produced milk, fat, protein (kg) and the number of days in lactation from r=-0.468 to r=-0.485 (P <0.01). Grazing of dairy cows at mountain farms has a better value of the composition of milk fat from a health perspective, but at the account of lower production.