I was reading an article in a trade magazine the other day which was commenting about the average carcass weight of recent beef. Beef has gotten bigger from some feedlots and the reasons for this are multiple. One is simply introducing larger breeds into the mix. This has been going on for hundreds of years and it is a natural way to increase size. For example if a breeder mixes an Angus with a larger Charolais you end up with bigger beef that should have some of the higher quality traits of the Angus. Advances in breeding and the ability to track generations have resulted in seedstock ranchers growing exactly the type of cattle they want, and for many that may mean larger cattle.
There are other reasons why cattle have gotten larger. Feed is being managed in ways that can maximize the growth of cattle. Fermenting hay and steaming grains can bring out more nutrients so cattle can actually grow on less feed. Keeping track of the animals diet and exact ration is very important for growth.
Another aspect is the use of steroids and hormones. Many cattle are implanted with a steroid in their ear upon arriving at the feedyard. This steroid is released for a few days and then the animal goes through a long period of feeding before it is sent to market. The steroid is, for the most part, depleted to low levels before slaughter and the end result is about a four percent gain in size. So this will explain some of the gain but most feedlots have been using these for years.
Why are cattle getting even bigger these days? We cut a boneless 0x1 striploin the other day that weighed 17.4 lbs! Thats big and impossible to cut into a thick 8 oz portion steak for a quality restaurant.
Another tool being used by feedlots today is a different feed supplement called beta- agonists. Beta -agonists are used on humans for asthma relief. Are these cattle having trouble breathing?? Not exactly. Beta-agonists are used to grow muscle faster by increasing the efficiency of the feed. Here is a very good explanation and shows the different types used today. http://fyi.uwex.edu/wbic/files/2010/11/Beta-Agonists-Factsheet.pdf The gains are substantial and the real savings is in the amount of feed the animal needs to grow. The most popular brand name is zilpaterol hydrochloride (Zilmax) is produced by Merck.Here is a bit of text from a beef grower about the use of a beta-agonist...
Beta agonists, like ractopamine, work by activating the beta 2 receptor on the muscles of my cattle. This binds specific beta receptors in the muscle cell membranes and increases protein synthesis. What does this mean exactly?
1.As animals grow larger and get close to the time of harvest, their bodies tend to turn nutrients into fat instead of lean muscle. Ractopamine encourages or repartitions those nutrients into muscle growth through protein synthesis rather than fat deposition.
2.This allows the animal to make more lean muscle (what we want to eat), and less fatty tissue (what we do not want to eat).
3.By making more muscle and less fat from nutrients, the animal becomes a more efficient user of its food thereby reducing the total environmental footprint of its food production. http://feedyardfoodie.wordpress.com/2012/05/31/the-great-puzzle-what-role-does-a-beta-agonist-play-on-my-farm/
So this explains why many cattle have gotten larger and also why they are leaner. Lean beef may have eye appeal in the super market but not in a fine steakhouse. And the beef's flavor is also effected. There seems to be less depth of flavor because it is taking less time to grow cattle so they end up in the market younger, therfore less time to develop more complex taste. But as we see drought conditions continuing in the midwest and west, we will see more and more use of beta-agonists. As feed prices soar, cattle growers want to sell faster. Everyday on feed costs them big bucks.
Beta-agonists have been deemed safe by the FDA but here is an article that sheds more light on the discussion. http://chronicle.com/article/As-Beef-Cattle-Become/131480/ It certainly is an interesting tread of comments afterward. Some program beef processors, such as those seeking higher marbling and smaller sized cattle, have asked feedlots to not overuse the beta-agonists so the beef can fatten. Any natural beef program will not allow them.
The size of beef has gotten larger, no doubt, and the cyclists in the Tour de France have gotten faster, they are both using similar substances to grow muscle. Beta-agonists are one of the many substances banned in professional bike racing. The use of beta-agonists is banned from animal feed in the EU and many other countries around the world. I'm not an expert in pharmaceutical study and I don't know the long term chronic effects of the use of these substances. I'm a butcher looking for marbling and flavor and some of today's beef seems to be lacking in both. I'm also a cyclist and long time racing fan and that sport has also lost a lot of flavor in recent years.