Population structure, genetic diversity, and reproductive efficiency in the autochthonous Busha cattle breed

<br />Autochthonous cattle breeds represent important resources ofgenetic diversity. The Busha cattle breed isreared inthe Balkan Peninsula and ischaracterised byhigh adaptability, resilience, longevity, small body size, and low maintenance and production requirements. During the 36-year observation period, the total population ofthe autochthonous Busha cattle breed inthe Republic ofCroatia amounted to10411 animals. Pedigree completeness for the total population, considering the first parental generation, was 97.1%. The average inbreeding coefficient was 2.44%, ranging from zero to42.6%, while the average relatedness coefficient was 3.56% inthe total population. The effective population size, calculated inthe reference population based onthe individual increase ininbreeding, was 63.3. The probabilities ofgene origin inthe reference population were <i>f_e</i>– 38.0, <i>f_a</i>– 33.0, and <i>f_g</i>– 25.4, indicating aloss ofgenetic variability due togenetic drift (<i>f_g</i>/<i>f_e</i>– 0.66) and abottleneck (<i>f_e</i>/<i>f_a</i>– 1.15). Inthe population ofthe autochthonous Busha cattle breed, the effective number ofancestors (<i>f_a</i>) was smaller than the effective number offounders (<i>f_e</i>). Increased relatedness among animals was observed, which could affect the long-term conservation ofthe population.