Evaluation of reproductive performance and genetic variation in bulls of the Polish White-Backed breed.

The aim of the study was to evaluate genetic variation, reproductive performance and the degree of relationship of White-Backed bulls entered in the breed registry and approved for breeding. The study included 32 bulls of the White-Backed (WB) breed with an entry in the breed registry and used for breeding in the years 2003-2015. Eleven microsatellite DNA sequences (TGLA222, BM2113, TGLA53, ETH10, SPS115, TGLA126, TGLA122, INRA23, ETH3, ETH225 and BM1824) were used to analyse variation in the WB bulls. The bulls most often used for breeding were Chilon (1,073 doses), Mak (939 doses) and Jaguar (858 doses). The bulls Mak, Chilon and Jak had the greatest influence on the active population of White-Backed cattle, with the most daughters. In the analysed population of White-Backed bulls, a total of 79 different alleles were identified, with a mean 7.27 per locus. The analysed pool of microsatellite loci was characterized by high values for PIC, HO and HE (>0.6), and the entire population was in genetic equilibrium. The estimated level of inbreeding within the population ranged from -0.2277 (ETH225) to 0.0775 (SPS115), with a mean value of -0.0587.