Performance of Pre-Weaned Dairy Calves under Hot Arid Environment: Effects of Immunoglobulins and Age on Diseases and Mortality

Problem statement: A high mortality rate (crude mortality 43.6%) of pre-weaned dairy calves resulted in unavailability of replacement heifers in Kuwait. Dairy producers resorted to import pregnant heifers for herd replacement. This study was undertaken to investigate the effects of dam vaccination and age, serum Immunoglobulin (Ig) on disease syndromes and mortality in pre-weaned calves. Approach: Late pregnant Holstein Friesian dairy cows and heifers of five commercial dairy operations were divided into two herds: Treatment (T) vaccinated using Lactovac against Rotavirus, Coronavirus and Escherichia coli and Control (C) unvaccinated herds. Total of 1,088 newborn calves of above herds were also divided as T and C for studies from their birth to weaning at 90 days. Calves weighed at birth, fed colostrum, serum proteins and Ig (IgG, IgM and IgA) were determined; disease syndromes, morbidity and mortality rates were investigated. Results: Mean birth weight (34.25±SE 0.21 kg) of calves did not differ significantly (p<0.01) between treatments. Crude mortality rates differed significantly (p<0.01) ranging from 2.83-22.83% in calves among herds. Highly significant differences were observed in Ig classes of blood serum of calves: IgG (F 3.47 p<0.010), IgM (F 3.52 p<0.009) and IgA (F 3.66 p<0.008). The effects of Ig levels on calf morbidity rates were significant (p<0.05) on three disease syndromes: pneumonia, diarrhea and pneumo-enteritis. Vaccination of pregnant dams and oral administration of antibodies to newborn calves reduced calf morbidity and mortality rates. Major disease syndromes were pneumo-enteritis (34.6%) and pneumonia (33.8%). Younger calves were greatly affected by these diseases. Conclusion: Inadequate levels of passive immunity of young calves were commonly found in Kuwaitʹs farms. This study demonstrated the importance of passive immunity of calves by ensuring adequate levels of serum Ig and protein levels.