Quantitative analysis of yearling traits in Senepol cattle carrying the slick hair gene

Senepol cattle carrying the slick hair gene are phenotypically characterized by short and sleek hair, which increases resistance to heat stress. To assess the impact of the slick hair genotype on growth, carcass, precocity, and feed efficiency traits, records from 5,176 purebred Senepol cattle undergoing commercial performance tests in Brazil were used. The animals were classified as homozygous for slick hair (SS) and heterozygous (Ss) and non-carriers (ss). The phenotypic results showed that heterozygous individuals were superior (P < 0.05) for yearling weight compared to others. When the results were expressed as expected progeny difference, Ss individuals were superior to SS individuals (P < 0.05) for yearling weight. While for ribeye area, SS individuals were superior (P < 0.05) compared to ss. In conclusion, genetic improvement programs for the Senepol breed should focus on strategies that promote the slick hair phenotype, to improve adaptability to tropical conditions without compromising progress in other traits.