The beef on beta-agonists
Cattle in packing plants are showing signs of lameness, sprouting welfare issues around beta-agonist intake.
This issue was first brought to attention when Lilly Edwards-Calloway from JBS showed a video of lame, stiff-gaited cattle at the National Cattlemen’s Beef Association (NCBA) summer meeting in early August.
Beta-agonists are growth promotants that mimic the action of naturally occurring hormones. They work by shifting an animal’s metabolism to more efficiently convert feed into protein rather than fat.
In 2012, approximately 70% of fed cattle were receiving a beta-agonist. The summers of 2011, 2012, and 2013 brought extreme heat conditions across the Plains, causing greater-than-expected late-summer mortality.
On August 7, 2013, numerous incidents were reported of impaired cattle mobility. In other words, the cattle refused to move even though there were no signs of pathology such as foot rot. From August 7 to September 23, Merck temporarily suspended sale of fed cattle on Zilmax (a beta-agonist made by Merck) while Cargill, JBS, Tyson, and National Beef all suspended the acceptance of Zilmax-fed cattle.
Chris Reinhardt, Kansas State University Extension feedlot specialist, said that this issue of “reluctance to move” is real. This was not seen at just one packer, he observed. He said it wasn’t as if one large packer claimed this and others just followed the leader; this reluctance was observed at various packing plants.
It is important to note that there were not any food safety or FDA issues involved.
Who’s it affecting?
Some cattle fed beta-agonists show these characteristics, while others are completely fine. Temple Grandin, Colorado State University professor of animal science, says she observes this stiff, sore-footed walking in all four major types of fed cattle – Holsteins, Angus, Brahman crosses, and mixed beef breeds with no Brahman influence.
There is research being done on genetic interaction with beta-agonists. In a pen of cattle, Grandin noticed that a Simmental steer had become very large and stiff on beta-agonists, while a Hereford steer appeared more normal. Both KSU experts and Grandin point out a few key factors that regularly correlate with “statue steer.” The behavior seems to associate with extreme heat events in heavy, finished cattle with predominantly black hides. However, the effects are odd and uneven, most likely due to uneven feed mixing.
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How to avoid the issues
There are some well-managed feedlots that have been feeding beta-agonists, and the cattle have not shown the mobility issues in the packing plant. Grandin pointed out a few key management strategies she believes are used to avoid problems:
- Sort cattle by size to avoid feeding beta-agonists to larger cattle as well as those with health or foot problems.
- Carefully mix feed using the lower range of the recommended 60-mg to 90-mg dose per animal. Extensively test random samples from the feed bunk to ensure consistency.
- Add roughage to the diet.
- Practice low-stress handling methods including working the cattle early in the morning during hot weather.