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Holstein steers that get hormone implants perform as well as implanted beef cows

17 February 2020

US - Holstein steers that get hormone implants grow faster than those that do not receive the implants, and they get as big as beef cattle breeds, according to Penn State researchers, who say that's good news for dairy farmers struggling to keep their operations financially viable.

In one of the first studies to track the effects of hormone implants in Holsteins - and in what is believed to be the only study to track hormone levels in their blood and muscles - researchers closely followed the development of 70 Holstein steers in an experiment at the Pennsylvania Department of Agriculture's Livestock Evaluation Center.

The study is important because Holsteins - traditionally considered dairy cattle - now supply up to 20 percent of the beef market in the United States, said researcher Tara Felix, assistant professor of animal science in the College of Agricultural Sciences.

The research was aimed at determining the effect of steroidal implants on growth performance, carcass characteristics and estradiol-17 beta concentrations in the blood and muscles of Holstein steers fed a grain-based diet.

Holstein ear implant

The research team, led by Pedro Henrique Vilela Carvalho, a doctoral student in the Department of Animal Science, also assessed how long and how strongly the hormones influenced the growth of Holstein steers after implantation - evaluating the so-called payout period when producers can expect the hormone to boost growth.

Hormone implants have been used in beef cattle production to improve growth performance and feed efficiency for more than 50 years, and 90 percent of all feedlot cattle in the US receive implants, noted Felix, also the beef cattle specialist for Penn State Extension.

"But most of the available data on implants was collected in studies conducted on beef breeds," she said. "So, we focused on technology to enhance Holstein beef production."

In findings recently published in the Journal of Translational Animal Science, the researchers reported that Holstein steers responded to hormone implants very similarly to beef breed steers. The study revealed that implanted Holstein steers had about a 10 percent increase in weight gain and feed intake over Holstein steers that were not implanted.

In addition, carcasses from implanted Holstein steers were about 10 percent heavier on average, and loin muscle area increased when compared to carcasses from non-implanted steers.

That additional 10 percent meat yield from Holstein steers can be the difference between surviving and going under for a dairy farm grappling with low milk prices and declining demand, Felix pointed out.

Researcher presents

"Dairy steers are a byproduct of milk production," she said. "A cow has to have a calf to produce milk. This sounds cruel, but we don't necessarily need that calf for milk production. If it's a female, a heifer, we use it as a replacement animal to make more milk.

If it's a male, or a bull calf, then we turn it into a steer and 'finish it' - or feed it a high-grain diet - to improve its beef qualities."

Steers are bull calves that are castrated to reduce their aggression to farm staff and to each other. Holstein steers have become important to US beef production over the last decade. In 2011, just 5 percent of the cattle finished in the United States were Holsteins. But in 2016, that figure had risen to 20 percent of finished cattle - a 400 percent increase in just five years.

"There are a number of reasons for this, but one of the biggest reasons was that dairy producers were struggling during that same time frame, and they were looking for ways to make more money on these steers," Felix said.

"And beef from Holsteins is not just ground - more than 80 percent of the animals that were in this trial, regardless of whether or not they received an implant, graded USDA choice or above, which means they likely became premium steaks."

Hormone used in beef cattle production continues to be an uncomfortable topic for Americans, Felix explained. The average consumer doesn't understand the production supply chain, she argued, and they are subjected to misinformation.

"There are always hormones in food we eat - all living things have hormones," she said. "There is even a difference in hormone levels, depending on whether beef comes from a steer or a cow. Beef from females often has twice the hormone activity."

Also, Felix added, something as common as a potato has 300 times the hormone activity as a serving of beef. Other foods that have more estrogenic activity than beef are beans, peas and tofu - common protein substitutes for meat in the human diet.

"All of these hormones are 'natural,' and there is no such thing as hormone-free when it comes to the meat we eat. But that doesn't mean any of these foods are dangerous because of the hormone activity, and that includes meat."

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