Evaluating micronutrient concentrations in liver samples from abortions, stillbirths, and neonatal and postnatal losses in beef calves.

The primary objective of the current study was to describe micronutrient concentrations in livers collected during postmortem examination from 501 beef calves and fetuses in western Canada. The most frequently identified deficiencies based on reported ranges for aborted fetuses were magnesium, copper, and vitamin E. For stillborn, neonatal, and postnatal calves, the most common deficiencies were magnesium, vitamin A, and vitamin E. However, for calves that died after 3 days of age, selenium deficiency was also very likely. Concentrations of all micronutrients examined in the study except zinc (P = 0.85) were different among fetuses, stillbirths, and neonatal and postnatal losses. This included liver selenium, copper, manganese, molybdenum, iron, magnesium, vitamin A, and vitamin E (P < 0.01). The percentiles of micronutrient concentrations for each age group, empirical prediction intervals for individual calves, and model predicted confidence intervals to compare with average concentrations from groups of calves were summarized for each age group. Information on cow, calf, and herd management attributes were available for 221 samples from 106 herds collected as part of study 1. Cow age, supplementation history, water quality, and herd location were associated with the concentration of iron, zinc, and molybdenum. The current study is unique in the number of samples included from young calves that were submitted as part of routine surveillance and not based on suspicion of either deficiency or toxicity. Most previous studies have been focused on older animals or fetuses and have contained a mix of beef and dairy animals with little or no information on their supplementation history.