Comparative analysis of Santa Inês and Dorper crossbred sheep: productive and reproductive efficacy in the semi-arid

Abstract

This study evaluated the productive and reproductive performances of Santa Inês sheep and their Dorper crossbreeds during the lactation period amidst the dry season in the semi-arid region of Paraíba, Brazil. Conducted at the experimental goat farm of the State University of Paraíba (UEPB), Campus IV, Catolé do Rocha, the investigation included a cohort of 24 ewes (12 Santa Inês and 12 Dorper crossbreeds [comprising 87.5% Dorper and 12.5% Santa Inês]) and 30 lambs (10 males and 20 females). Observations were recorded from birth and continued at 30-day intervals up to 90 days. Using a two-way ANOVA with a 2 x 2 factorial design (two genetic groups and two sexes), the study monitored both ewes and lambs. The animals adhered to traditional regional management, grazing in paddocks by day and secured in shelters by dusk. The study found that both Santa Inês and Dorper crossbred ewes produced similar quantities of milk (P=0.8310) for the first 60 days of lactation. There was no discernible effect of the ewes’ genetic backgrounds on their live weights, body condition scores at lambing, throughout the subsequent 30, 60, and 90 days of lactation, or on the overall productive efficiency and total weight of weaned lambs per ewe. In contrast, Dorper lambs demonstrated a higher weaning weight (P=0.0349) and greater weight gain (P=0.0403). The study also noted that the sex of the lambs did not notably influence their performance within the first 90 days of suckling.