Growth and meat productivity of lambs depending on the genotype according to the A blood group system of their mothers

The Askaniy fine-wool breed of sheep is known for its high meat and wool productivity, as well as its adaptability to steppe conditions, making it a valuable subject for breeding research. This study aimed to investigate the relationship between maternal genotypic characteristics and key lamb productivity indicators to improve the efficiency of breeding programmes. The research was conducted from 2022 to 2024 at the Educational, Scientific and Practical Centre of Mykolaiv National Agrarian University (Ukraine). The sample comprised 60 clinically healthy Askaniy finewool ewes aged 2 to 5 years, all kept under uniform conditions, with minimal fertility variation and no hereditary pathologies. The most prevalent maternal genotype was A(-), associated with stable reproductive performance. The Ab genotype exhibited the highest milk yield and fertility, while Aa showed balanced characteristics. The Aab genotype was notable for high fertility and frequent multiple births. Lambs born to dams with the Ab genotype had the highest average birth weight (4.2 kg), daily weight gain (180 g), and weaning weight (18.2 kg). The lowest productivity indicators were observed in the A(-) group, although this group displayed strong adaptive traits. At seven months, lambs from Ab dams showed the highest slaughter weight (21.4 kg) and meat yield (53%), outperforming the Aa, A(-), and Aab groups. The maternal genotype also influenced fat content, bone ratio, and meat quality. These results confirmed that maternal genotype significantly affected lamb productivity, with the Ab genotype showing the greatest potential in terms of growth, milk production, and meat yield, highlighting its value for selective breeding programmes