Manifestation of signs of milk productivity of firstborn cows depending on the productivity of their female ancestors

Abstract

One of the most important breeding methods in cattle breeding is the determination of genetic similarity in productive traits of female ancestors and their descendants. In view of the above, the aim of the study was to determine the variability of cow milk production traits depending on the productivity of their mothers and fathers' mothers. The studies were conducted on farms located in different climatic zones of Ukraine, namely: SE DG “Oleksandrivske”, Vinnytsia region (Forest-Steppe zone, n = 714), LLC SHP “Imeni Volovikova”, Rivne region (Polissia zone, n = 1840) and SE “Experimental Farm “Askaniyske” (Steppe zone, n = 926) on firstborn and full-grown cows (III lactation) of the Ukrainian Black-and-White dairy breed. The sample included cows that had completed at least the third lactation at the time of the study. It was found that the most productive cows in the controlled herds were those whose mothers' milk yields for the highest lactation reached more than 8000 kg, and the mothers' milk yields of the fathers, depending on the breeding zone, ranged from 9000 to 15000 kg. A certain influence of mothers on the value of indicators of cows' milk production traits is evidenced by correlation analysis. Thus, a rather significant straightforward and reliable relationship was established between the milk yield of mothers and their daughters in the controlled farms, and between the milk yield of mothers and the fat content of daughters, this relationship was inverse, but reliable. The correlation between maternal fat and milk yield and fat and milk yield of daughters was multidirectional and insignificant. The coefficient of heritability, which was determined by doubling the mother-daughter correlation, ranged from 0.47 to 0.59 for milk yield, from 0.30 to 0.55 for milk fat yield, and from incorrect (negative) in animals from the Steppe zone (-0.27) to positive (0.18) in animals from the Polissya zone. The analysis of variance confirmed a certain predetermination of phenotypic variability of quantitative traits of milk production depending on the productivity of mothers and mothers of fathers established by the comparison of group means. Thus, their mothers had a somewhat greater, although not significant, influence on milk yield (depending on the farm and lactation – 3.8–6.9 %) and fat content in cows' milk (4.2–6.6 %), and their fathers' mothers had a somewhat lesser influence (2.1–4.2 and 2.0–4.5 %, respectively).