Assessment of selenium supplementation by systemic injection at birth on pre-weaning calf health
Keywords:selenium, vitamin E, calf health
The objective of this randomized clinical trial was to evaluate the effect of selenium and vitamin E supplementation by systemic injection on dairy calf health and growth during the pre-weaning period. The study was conducted at 39 dairy farms in Ontario, selected through a convenience sample of farms in close proximity to either Guelph or Kemptville. A total of 835 Holstein heifer calves were enrolled in this study. At birth, calves were randomly allocated to receive selenium and vitamin E supplementation by injection (3 mg sodium selenite and 136 IU dl-a-tocopherol acetate) or a placebo solution. At enrollment, producers recorded time of birth, calving ease, and colostrum feeding status. At weekly visits to the individual dairy farms, trained technicians collected measurements and samples from enrolled calves. Blood was collected from calves that were up to 8 d of age to assess the concentration of serum total protein and selenium. Between 8 and 15 d of age, fecal samples were collected to identify the presence of rotavirus and Cryptosporidium parvum (C. parvum) using a commercially +available lateral immuno-chromatography antigen detection kit. Each enrolled calf was also weighed and assessed for health scores during the first, second, and seventh weeks of life. The average serum selenium concentration (SD) in treated calves was 0.08 μg/mL (0.02), versus 0.06 μg/mL (0.01) in control calves. The incidence of failure of passive transfer (FPT) among study calves was 21%, and did not differ between treatment groups. The mean average daily gain (ADG) for the study period was 1.43 lb (0.65 kg)/day and was not associated with selenium and vitamin E supplement injection. Of the 761 fecal samples tested, 272 (36%) and 118 (16%) tested positive for C. parvum and rotavirus antigen, respectively. Selenium and vitamin E treatment had a protective effect against rotavirus infection. However, there was no effect of experimental treatment on C. parvum infection status. Reduced odds of treatment for diarrhea was also seen in the selenium and vitamin E treatment group. This study suggests that selenium and vitamin E injection at birth could improve pre-weaning health by reducing rotavirus infection and diarrhea.