Growth Promotant Technologies: Impact on Beef Production and Meat Quality - Background

By Christina Bakker

The United States produced 17.6% of the world’s beef using only 6.1% of the world’s cattle in 2021 (FAO). Additionally, the amount of beef produced per head increased by over 67% from 1961 to 2019 (USDA NASS). While characteristics, such as genetics and nutrition, have played large roles in these increased efficiencies, the utilization of growth promotant technologies has also made large contributions to the increase in pounds of lean tissue produced per carcass.

As the name suggests, growth promotant technologies are tools that livestock producers can use to help their livestock grow in a more cost-effective and efficient manner. A study conducted in 2008 estimated that eliminating the technologies of parasite control, implants, sub-therapeutic antibiotics, ionophores, and beta-agonists would increase per-head production costs by $360 over an animal’s lifetime and the cost of finished livestock would need to increase by 36% (Lawrence and Ibarburu, 2008). In addition to the economic benefits of using technology, there are also improvements in the efficient use of resources. According to a report commissioned by the Food and Agriculture Organization of the United Nations (abbreviated as FAO), twice as much animal protein will be needed to feed the global population by 2050 as was produced in 2011 (McLeod, 2011). The world population is becoming increasingly more urban, and the arable land for producing livestock feeds is limited. This means that livestock production must produce more food per animal while using fewer land and crop resources. A study published in 2012 found that natural production systems (those that do not use growth promotant technologies) required 77.5% more cattle to produce the same amount of beef as conventional production systems that utilize growth promotant technologies (Capper, 2012). More animals mean more land and feed is also needed. Therefore, the importance of these growth promotant technologies in the toolbox of cattle producers cannot be understated. But what are the common technologies and how do they work?

Understanding Common Growth Promotant Technologies

Antibiotics

The first class of growth promotant technologies to be addressed is antimicrobials, which encompass antibiotics and ionophores. Antibiotics are no longer available solely for the purpose of growth promotion; however, animals that are healthy and feel well will ultimately eat more and gain faster compared to sick animals. There is a benefit to judicious utilization of therapeutic antibiotics. However, there are some antibiotics that can be used on a sub-therapeutic level to improve animal health. Specifically, some feedlots opt to use tylosin phosphate to reduce the incidence of liver abscesses. It is important to note that feedlots need to work with veterinarians to use tylosin phosphate according to the Veterinary Feed Directive rule, and many producers are looking for an alternative solution to liver abscesses. Currently, one condemned liver costs the beef industry around $23, although that is not the only cost. Livers with abscesses also tend to be adhered to the body wall of the carcass and need to be cut away, reducing carcass weight and ultimate value of the carcass.

Ionophores

Another antimicrobial class used in the beef industry are ionophores. Ionophores are commercially available antimicrobials classified as nontherapeutic antibiotics. They work through a process called competitive inhibition and alter the proportions of ruminal bacteria from lactic acid and acetic acid producing bacteria to propionic acid producing bacteria, ultimately improving digestive efficiency. By increasing digestive efficiency, animals can convert feed to body mass more effectively by using less feed. These tools also reduce the risk of death loss from digestive upset (bloat) and aid in the control of coccidiosis.

Implants

Implants are small pellets that can be inserted into an animal’s ear that contain growth promoting hormones. Common hormones used in implants are estradiol, progesterone, zeranol, and trenbolone acetate. These hormones work within the body to promote the increase of muscle tissue and ultimately increase the hot carcass weight for implanted animals. For more information on implants and hormones in beef cattle, see the articles, Hormones in Beef: Myths vs. Facts and Questions and Misconceptions Surrounding Implants.

Beta-Agonists

The final growth promotant technology to be discussed in this article are beta-adrenergic receptor agonists, also referred to as beta-agonists. The commonly used beta-agonist in the United States is ractopamine hydrochloride, and it is administered to cattle through dietary inclusion. Beta-agonists work by binding to beta receptors on muscle and fat cells and altering the metabolic processes in the cells. This alteration allows animals to shift their growth from increasing fat to increasing muscle, resulting in a higher yielding carcass. Beta-agonists are regulated for dosage, length of time they can be fed to animals prior to harvest, and withdrawal time. Lawrence and Ibarburu (2008) found that the use of beta-agonists increased average daily gain by over 14% and reduced the feed-to-gain ratio by over 12% over the period of use, solidifying beta-agonists as another means to producing more beef with fewer inputs.