FATTY ACID COMPOSITION OF MILK FAT OF PUREBRED AND CROSSBRED FIRST-CALF HEIFERS

The purpose of research is to study the fatty acid composition of milk fat from first-calf heifers of different genotypes in Western Kazakhstan. Objectives: determination of the content of saturated, monounsaturated and polyunsaturated amino acids in the milk fat of cows of first-calf heifers of black-and-white breed (I group), Holsteins of German selection (II group), Holsteins of Dutch selection (III group), crossbreeds ½ Holstein of German selection × ½ Black-and-white (Group IV), ½ Holstein Holstein selection × ½ black-and-white (V group). The scientific and economic experiment was carried out in 2019–2020. in LLP Agrofirma Akas of the West Kazakhstan Region of the Republic of Kazakhstan. The experimental groups, formed according to the principle of analogous groups, taking into account origin, live weight, physiological state, included 15 animals each. Determination of the amino acid composition of the fatty phase of milk was carried out by gas chromatography. The leading position in animals of all experimental groups was occupied by the class of saturated fatty acids (SFA), followed by monounsaturated (MUFA) and polyunsaturated (PUFA) fatty acids. At the same time, depending on the genotype, the amount of unsaturated fatty acids in the milk fat of first-calf heifers of the experimental groups was in the range of 60.38–61.96 %; monounsaturated – 29.23–30.67; polyunsaturated – 4.48–4.66 %. Female peers of groups II–V were inferior to animals of the black-and-white breed in terms of the amount of saturated fatty acids by 1.28–1.58 % (P < 0.05). Milk fat of crossbred first-calf heifers of groups IV and V differed in the minimum specific gravity of saturated fatty acids, animals of the Holstein breed of German and Dutch selection of groups II and III occupied an intermediate position. Animals of the black-and-white breed of group I were inferior to peers of groups II–V in terms of the amount of monounsaturated fatty acids by 1.19–1.44 % (P < 0.05), the content of polyunsaturated fatty acids – by 0.04–0.18 % (P > 0.05…P < 0.05). The most common monounsaturated fatty acids in the milk fat of first-calf heifers of the experimental groups were palmitic (C16:0 – 27.04–27.13 %), myristic (C14:0 – 11.03–12.04 %) and stearic (C18:0 – 8.14–11.88 %).