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Fatigued cattle syndrome possibly mitigated by low-stress handling techniques

by Wyoming Livestock Roundup

According to a news release from Kansas State University (KSU) in August 2015, “Abattoirs throughout the United States reported concerns about slow and difficult-to-move cattle and other mobility problems that developed soon after arrival at the facilities.”

Reports from the abattoirs were brought to attention in the summer of 2013, and symptoms were described as very similar to pigs with fatigued pig syndrome.

In response to concerns, a team of researchers at KSU began an investigation, culminating in a report titled, “Description of a novel fatigue syndrome of finished feedlot cattle following transportation,” which appeared in the July 15 issue of the Journal of the American Veterinary Medical Association.

“While we don’t know the cause, it appears to be multifactorial in nature but warrants further investigation,” reported co-author Guy Loneragan, professor of food safety and public health at Texas Tech University.

Beta agonists

One potential contributing factor to the clinical symptoms seen in cattle, referred to as fatigued cattle syndrome, is the use of beta agonists, such as Zilmax (zilpaterol hydrocholoride) and Optaflexx (ractopamine hydrochloride).

Beta agonists are used to increase feed efficiency by causing more dietary energy to be directed toward the deposition of muscle rather than fat.

Wyoming State Veterinarian Jim Logan explains, “They are approved for feeding cattle during the last phase of the finishing period. These drugs do not pose a threat to human health or they would never have been on the market to start with.”

Although debate over animal welfare has arisen over the use of beta agonists, researchers have not seen a direct link between the drugs and fatigued syndromes in pigs or cattle.

“What they’ve found, at least on the cattle side, is that cattle can develop this fatigue syndrome whether or not they are being fed beta agonists. Suffice to say, beta agonists may be a contributing factor, but they are certainly not the only cause of it,” notes Logan.

Cattle stress

In fact, in the KSU news release, report co-author Dan Thomson remarks, “Our landmark paper places an emphasis on cattle stress at the end of the feeding period with items such as heat load, animal size, cattle handling at shipping, time of day of shipping, animal transportation and other issues that could be causing stress of large cattle during the summer time.”

  Logan explains that highly stressed cattle appear to be much more susceptible to fatigue symptoms and that those symptoms are comparable to a physically unfit human who goes out for vigorous exercise.

“Fatigued cattle syndrome consists of a series of clinical signs, including a reluctance to move, a decreased flight zone, muscle tremors and a stiff gait,” he mentions.

When chemistries are run on blood samples from those animals, researchers see abnormal lactic acid concentration, a low pH and an increase of an enzyme known as creatine kinase (CK).

“If these animals are not physically fit and they are handled aggressively, i.e. forced to run, chased around or hit repeatedly with the hot shot, it does increase this lactic acid build up in their system. It’s just like a person who has not worked out for months going out to lift weights or exercise all day. The next day they are going to be stiff. It’s the same basic principle,” he describes.

Heavy cattle

Over the last number of years, finishing weights on cattle have increased dramatically, and Logan believes this may be one reason the condition has been seen more often in recent years.

“Researchers see fatigued cattle syndrome a lot more in heavy animals than they do in skinny or under-conditioned ones,” he adds.

Symptoms are also noted more frequently after animals have been handled and transported.

“There are a lot of cumulative risk factors or contributing stress factors that lead to the fatigue. In reports I’ve read, many of the animals that showed up at these slaughter plants, and even some that were not able to get up or were very stiff and had a reluctance to move, improved significantly if they were left alone over night,” Logan says.


Although Logan has not been notified of any fatigue cases in Wyoming, he notes that symptoms are most often identified in slaughter or processing facilities.

“We’re not a terminal state,” he comments. “If it’s happening, I’m not aware of it in Wyoming.”

Yet, producers can still be aware of the potential implications of different cattle handling techniques and stressful situations.

“Some of the stress factors are heat or temperature related. If it’s really hot and animals are being shipped in the heat of the day, there are a lot of things we can do to mitigate this, such as providing shade for the cattle, staying quiet around them, not working them fast, not making them run, providing adequate water and handling them in a non-aggressive manner,” he explains.

Learning more

The KSU report states more research is necessary and that veterinarians and cattle handlers should learn more about fatigued cattle syndrome so that measures can be implemented to prevent the condition or at least minimize its impact on animal welfare.

“For the most part, I believe Wyoming producers do a good job of handling their livestock and taking good care of them. I also think there are always things people can learn, and it would behoove producers everywhere to look into animal handling techniques to try to improve the wellbeing of their livestock,” remarks Logan.

Natasha Wheeler is editor of the Wyoming Livestock Roundup and can be contacted at

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