Approved cattle growth implants do not have a large impact on fat metabolism but they do increase muscle mass by making more protein, said an Elanco Animal Health veterinarian.
“We have to find a way to manage it so we don’t mess it up,” Sandra Gruber said at the Canadian Beef Quality symposium held in Calgary July 8.
Research on the impact of hormones shows tenderness can be improved with techniques like proper aging.
“Marbling and tenderness are very complex traits and we don’t have a very good handle on predicting which ones will be tender,” she said.
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The variation in tenderness among young, conventionally finished cattle is largely attributed to differences in the extent of muscle fibre degradation after slaughter.
In the first 24 hours after death, rigor mortis develops and the beef is tough. Over time, protein degrades and becomes more tender.
Studies have compared implant strategies, the potency and impacts on carcass quality.
On average, the use of implants increased hot carcass weights by 40 pounds compared to hormone-free animals. Moderate to aggressive use saw an even greater gain but shear force scores showed the meat was tougher. Aging the carcass can mitigate some of that. In addition to implants, some beta agonists, which relax the muscles in the airways, are allowed in feed mixes. They do not appear to affect tenderness scores.
Ractopamine was approved three years ago and does not require any withdrawal time.
Zilpaterol was also approved last year and adds an extra 30 lb. of muscle. Marbling is reduced but the drug does not appear to make the meat tougher.
