Environmental Effects on Preweaning Calf Health

Neonatal calf health is an important factor in the productivity and profitability in the beef cattle industry, influencing preweaning survival, growth, and long-term performance. The overall objective of this thesis is to characterize risk factors that contribute to health issues in young beef calves. The first objective is to review literature exploring the environmental factors affecting preweaning morbidity and mortality, including hypothermia, precipitation, and wind. Management strategies such as the effect of environmental conditions of calving location, body condition score in dams at parturition, and the impacts of dystocia on calf health will also be discussed. Gaps in current research surrounding this topic are highlighted. The second objective is to test the hypothesis that calves exposed to harsher environmental conditions at birth (i.e. lower average temperature, freezing temperatures, precipitation, mud, and/or snow) will have increased odds of illness compared to those born in more moderate conditions. To accomplish the second objective, cow-calf producers from across Nebraska were asked to record environmental conditions during calving and provide health treatment records for three calving seasons. Statistical analysis was performed on each herd independently. Snow was significantly associated with illness in Herd A. Average temperature was significantly associated with illness in Herd D. The association between birth year and calf illness was significant in Herd F. Days from the start of calving season was significant in Herd B, Herd E, and Herd F. There were no significant associations observed between all variables tested and calf illness in Herd C (p > 0.05). These findings highlight that due to confounding between environmental and management factors, effectiveness of calf health interventions varies by operation and should be evaluated locally. Advisor: Brian L. Vander Ley