A condition well known in pigs may be a rising concern in the cattle industry.
Fatigue pig syndrome (FPS) has been a topic in the swine industry for years, with affected animals being unable to walk, having severe muscle tremors, and difficult respiration. Only within the past few years has the syndrome been described to the cattle industry as well.
At a recent cattle handling and stewardship conference in Fort Collins, CO, the topic of fatigued cattle syndrome (FCS) was mentioned several times.
FCS leads to similar mobility issues in cattle as FPS does in hogs, which results in downers at the packer facility, ultimately ending with the affected animals being euthanized. At a time where animal welfare and handling are becoming growing priorities, incidences of FCS can be prevented and have vast impacts on the wallet.
Recent research
If you’re not familiar with the topic, you’re probably not alone. Most of the leading research findings about the condition stem from one study published several years ago.
Following numerous reports during the summer of 2013 from slaughter facilities concerned with cattle and their mobility, researchers from Kansas State University (KSU), Texas Tech University, and Iowa State University conducted a study to determine the cause of lameness. The study was then published in the Journal of the American Veterinary Medical Association.
Cattle displaying mobility issues upon arrival to the packer facility were observed to have similar clinical signs seen in pigs with FPS. The syndrome causes pigs to be non-ambulatory, unwilling to move, and without obvious signs of injury, trauma or disease.
Typically, pigs affected with this condition are associated with stressful handling, transport and being fed high levels of the beta agonist ractopamine hydrochloride.
Unlike pigs, cattle with FCS would slough their entire hoof wall from one or more digits, resulting in extreme discomfort.
These observations brought up the question whether or not feeding beta agonist zilpaterol hydrochloride (Zilmax) affected cattle mobility at slaughter. This led to the eventual suspension of the drug after packers stopped accepting cattle fed with the beta agonist.
Much of what we understand about FCS comes from case studies detailed in the 2013 study, highlighted below.
In an attempt to compare the similarities between FPS and FCS, two shipments of cattle were observed in the early fall of 2013.
The first shipment of cattle contained 200 crossbred cattle less than 30 months old, transported 249 miles from a commercial feedlot. The cattle had been fed a high concentrate finishing ration with zilpaterol.
Once unloaded into holding pens, many cattle became lethargic and unwilling to move. Around 10 percent of cattle also began sloughing their hooves. Cattle with sloughing hooves were in extreme pain and had rapid shallow respirations, muscle tremors, and refused to move.
Of the cattle sloughing hooves, 15 were immediately euthanized by captive bolt. An additional 17 cattle reluctant to move, but not displaying signs of injury, were able to rest overnight in the pens. Of the 17, 15 cattle recovered and were moved through slaughter, and the remaining two were euthanized.
A second case of FCS was observed a month later in a Holstein steer less than 30 months old with a group of cattle from a feedlot. The cattle were not fed a beta agonist, but the steer still sloughed his hoof walls in the holding pen and was then euthanized.
After it was discovered that a similar case occurred a month prior to the first major case studied, Tyson banned the purchase of zilpaterol-fed cattle.
It was not completely ruled out that the severe hoof sloughing could be a result of carbohydrate loading, but the researchers noted the cases were much more severe than cases typically seen as a result of carbohydrates.
The other clinical symptoms experienced by the cattle—signs of stress, labored breathing and a stiff gait—were all very similar to pigs with FPS. Pigs experiencing the condition tend to develop open mouth breathing, don’t want to move, and have muscle tremors.
Pigs with FPS were fed a high level of the beta agonist ractopamine and the withdrawal period caused behavioral changes in the pigs that made them more prone to stress. Pigs not fed ractopamine could also develop FPS as a result of aggressive handling, heavy body weight and steep loading and unloading ramps.
The close association of pigs and cattle receiving a fed beta agonist led to the speculation of the drug causing FCS as well. A sudden halt of feeding the drug due to a withdrawal period could cause metabolic changes that could become stressors to the animals.
However, cattle fed the beta agonist weren’t the only ones at risk. Time of day when cattle were being loaded, handling technique and the distance cattle walked to the trailer could all be factors for developing FCS.
Fatigue and stress cause a buildup of lactic acid and metabolic acidosis, which would result in muscle tremors and stiffness. Most of the animals allowed to rest following long distances were able to recover from the buildup and acidosis. Double-muscled cattle experienced clinical signs of FCS following exercise and stress more frequently.
FCS could also be a result of the weather as well. Most cases occurred during the summer and were rarely observed in the cooler months. The variation of increasingly heavier body weights within a truckload may have also played a factor into developing the condition.
Prevention
Although the beta agonist could be a factor in FCS, the researchers concluded the condition was more than likely multifactorial, and stress management and handling played a large role. Although typically occurring at the place of slaughter, producers also play a part in preventing cattle from experiencing FCS by practicing good stockmanship and stewardship.
Dan Thomson, coauthor of the 2013 study, and Chris Reinhardt of Kansas State University (KSU) have been developing a program to help prevent the condition in cattle. The program features educational modules, training videos and handouts to help all sectors of the industry identify and mange FCS.
“Providing a platform for education on FCS enables the beef industry to utilize our online training programs to improve communication throughout the food animal production chain, maintain our focus on cattle health and wellbeing, and enhance the safety of cattle and the people working with the animals,” Thomson said in a released statement by KSU. Look for more info on this topic in WLJ in the coming weeks. — Anna Miller, WLJ editor
