Interpretive Summary: Dietary zinc concentration and lipopolysaccharide injection affect circulating trace minerals, acute phase protein response, and behavior as evaluated by an ear-tag–based accelerometer in beef steers
By Anne Zinn
The National Animal Health Monitoring System estimates that bovine respiratory disease affects 21.2% of all beef cattle placed in feedlots. Bovine respiratory disease often affects cattle during the receiving period, which can involve many stressors; identifying morbid cattle early may lead to improved animal welfare through decreased morbidity and mortality and increased treatment efficacy. Symptoms of bovine respiratory disease can be mimicked using an injection of lipopolysaccharide and, due to the potential positive role of zinc in immune function, consulting feedlot nutritionists have recommended supplementing zinc with dry matter. This requires further research.
A paper recently published in the Journal of Animal Science assessed plasma trace mineral concentrations, the acute phase protein response, and cattle behavior when given various doses of injected lipopolysaccharide and supplemented with either 30 or 100 mg Zn/kg dry matter. It was hypothesized that regardless of lipopolysaccharide dose, plasma trace mineral concentrations and blood cell populations related to the acute phase response would decrease, but that increased supplemental zinc would lessen the severity of these changes. Additionally, it was hypothesized that ear-tag–based accelerometers would detect illness behaviors, such as less time spent eating or ruminating in cattle treated with lipopolysaccharide.
Overall, results of the present study suggested that increased supplemental zinc may alter the rate of recovery of zinc status from an acute inflammatory event. Additionally, ear-tag-based accelerometers used in this study were effective at detecting sickness behavior in feedlot steers, and rumination may be more sensitive than other variables. It is suggested that future work should evaluate proteins involved in transport and storage of trace minerals that would allow for a greater understanding of the mechanisms behind the lipopolysaccharide disruption of trace minerals homeostasis, which could potentially allow for more strategic trace minerals supplementation strategies for sick cattle.
The full paper can be found in the Journal of Animal Science webpage.