Interpretive Summary: Response of lactating dairy cows fed different supplemental zinc sources with and without evaporative cooling to intramammary lipopolysaccharide infusion: metabolite and mineral profiles in blood and milk
By Anne Zinn
A recent study published in the Journal of Animal Science aimed to determine the effects of evaporative cooling and dietary supplemental Zinc source on blood metabolites, insulin, and mineral concentrations, as well as milk mineral concentrations following intramammary lipopolysaccharide infusion during summer. Heat stress can negatively affect animals’ production, reproduction, and compromise their overall health; during heat stress, the likelihood of diseases, such as E. coli, increases. Recent studies have focused on milk somatic cell count and disease incidence, but there is still a lack of understanding of how different sources of supplemental Zinc affect metabolic and mineral responses during mammary inflammation or mastitis in lactating dairy cows. Therefore, the research team hypothesized that heat stress and dietary source of supplemental Zinc alter metabolic responses and mineral metabolism would after lipopolysaccharide infusion into lactating quarters of dairy cows.
Results of this study indicate that heat-stressed lactating dairy cows have more sensitive pancreatic insulin release induced by inflammation and that, when compared with cooled cows, non-cooled cows had a greater reduction in serum Zinc concentration and a delayed increase in skim milk iron concentration after intramammary lipopolysaccharide infusion. Following the intramammary lipopolysaccharide infusion, non-cooled cows maintained lower plasma glucose concentrations, but had a more rapid and prolonged increase in serum insulin concentration compared with cooled cows. Further research is necessary, but current results suggest that dietary sources of supplemental Zinc have no apparent impact on the metabolic and mineral responses of cows to intramammary lipopolysaccharide infusion.
The full paper can be found on the Journal of Animal Science website.