Possible effect of artificial insemination and multiple ovulation embryo transfer on the health and survival of Holstein-Friesian calves.

Reproductive technologies like artificial insemination (AI) and multiple-ovulation embryo transfer (MOET) are extensively used in cattle breeding, but their effects on the health and growth of calves remain unclear. This study evaluated the effects of AI and MOET on morbidity, survival and weaning weight in Holstein-Friesian heifer calves. A total of 366 calves (AI: n = 314; MOET: n = 52) were followed for 91 days from birth. Morbidity was classified based on the incidence and severity of diarrhoeal and respiratory disease. Weaning weights were contrasted with disease incidence. Statistical analyses included chi-square tests for categorical data and ANOVA for continuous data (P < 0.05). Survival and overall morbidity rates were not influenced greatly by reproductive technology. The prevalence of diarrhoeal disease was similar for MOET and AI groups (P > 0.05), but respiratory disease was greater and more severe in MOET calves (P < 0.05). Morbidity negatively impacted weaning weight in AI calves (P < 0.05) but had no significant impact on MOET calves. Season and colostrum quality significantly influenced survival, with greater survival rates noted for autumn-born calves and calves that received high-quality colostrum (>25% IgG) (P < 0.05). While reproductive technology had little effect on survival, MOET calves showed a heightened susceptibility to respiratory illnesses, highlighting the importance of targeted health management.