A recent study by USDA’s Agricultural Research Service and the University of Nebraska-Lincoln shows beta agonists don’t harm cattle. The thought that beta agonists do harm cattle was the primary reason for Merck Animal Health to remove its feed additive Zilmax last August. The Food and Drug Administration approved the product – which has been used to improve feed conversion and result in more beef from each animal harvested – which has been a priority since 1952.
This recent study took place for a 26-day period. Researchers collected blood, monitored body temperature and video images from 20 heifers that were divided into two groups. One group received the recommended dose of Zilmax – the other did not. On the last day of the trial – heifers were exposed to a simulated stress event to mimic the stress response that would be anticipated in cattle being shipped from the feedlot to the packing plant. Study results show heifers fed Zilmax had an increase in parameters indicating increased muscle mass – which was expected.
Researcher Ty Schmidt says results also showed heifers supplemented with Zilmax had a decreased production of cortisol – the stress hormone – and decreased body temperature during the simulated stress event. Overall – Schmidt says the results indicate while there are variations in the body temperature, endocrine and metabolic parameters and histopathology of major organs of Zilmax-supplemented heifers – the differences show no indication supplementation of Zilmax is detrimental to health or well-being in cattle.Share