VARIANT RS475678587C>T OF THE UBE3B GENE (HAPLOTYPE AH1) IN AYRSHIRE CATTLE INCREASES THE RISK OF STILLBIRTH IN DAUGHTERS OF MALE CARRIERS

The aim of our study was to analyze the reproduction dynamics and fertility rates Ayrshire cattle population in Russia assess level influence AH1 haplotype on incidence stillbirth. For an overall estimate, we used 390,769 records 67 dairy herds from 2003 2018. Against background stable growth, average stillbirth rate 3.33% abortion 0.075%. A high percentage (5.13%) heifers first fertilization event, there a abortions older cows (11 calving, 1.76%). An analysis 62,534 bulls with rs475678587C>T variant UBE3B gene (AH1 haplotype) (n = 69, which 51 were free 18 carriers AH1) for period 2002 2018 showed that proportion female offspring AH1-C completing at least one full lactation about one-third total livestock. results mating AH-F AH-C broodstock as whole (without taking into account genotype) did not reveal significant differences number stillbirths abortions. Linear regression status significantly affect rates. calving reproductive ability increase frequency stillbirths, confirmed by linear analysis, revealed effect bull fathers carrying AH1on experienced their daughters. Our studies confirm (haplotype has cow or heifer if father is carrier this genetic defect.