Project hopes EPDs can catch lameness early

Members of the Canadian Angus Association are asked to score cows when they come in this fall for pregnancy checks

Lameness in cattle is a painful condition that affects their welfare and overall performance.

Good feet and legs are primary considerations when selecting animals that can travel easily across the range.

The Canadian Angus Association received nearly $240,000 in federal funding for a two-year project to generate genomically enhanced expected progeny differences for feet and leg structure in the suite of EPDs available, said Kajal Devani, director of science and technology at the Angus association.

“Lameness impacts production but then it also impacts animal health and welfare,” she said.

“EPDs will help you predict animals that will have poor structure early because you are not going to see it early in life,” she said.

Producers know about the importance of raising functional, structurally sound animals. Proven genetic evidence helps with selecting strong animals.

“Feet and leg structure is probably genetic like a lot of complex traits. That means there is a contribution from a lot of different genes as well as the environment. We know very cold weather, standing in water, feed, all of these contribute to structural problems with feet and legs,” said Devani.

The Canadian dairy industry has been measuring and selecting for improved feet and leg strength for several years but assessing animals in extensive grazing systems is more challenging.

“We don’t really know how much lameness we have in pasture in terms of where somebody actually measured it.”

Right now the Angus association is collecting phenotypes, which are measurements or observations of an animal. This makes the genomic information more accurate but a large number of phenotypes are needed.

Members are asked to score cows when they come in this fall for pregnancy checks. A scoring guideline from the association is available. If an animal was culled, the reason should be included.

Veterinarian Karin Orsel at the University of Calgary’s faculty of veterinary medicine heads a team running lameness studies in Alberta feedlots. Orsel is also working with Devani to create genomic EPDs for leg and foot health as well as structure and ultimately, stayability in the herd.

Animals with good legs, feet and conformation are less likely to be affected by disease.

There are a number of reasons lameness may occur.

Foot rot may cause lameness, and it may be treated with antibiotics. However, a sole ulcer benefits from a good foot trim. It is an infection between the sole and the live tissue. An opening is needed at the bottom so it can drain and heal.

There are certified hoof trimmers in Alberta who have the proper equipment to handle dairy cattle, but not many chutes are available that can handle beef animals, said Orsel.

A bull may also have knee issues caused by a cruciate ligament rupture. Pain medications and/or rest are recommended.

The challenge in the beef industry is identifying the problem because the animals may not be seen as often as dairy cows moving in a barn, she said.

Veterinarians and producers need to spend more time diagnosing lameness because there are different forms. The question should be asked: does the animal not want to put weight on the leg or is it unable to put weight on it?

“That differentiation helps to find out what the cause can be. Certain causes of lameness really are the end of the animal’s life, like certain fractures in adult animals,” Orsel said.

Another active area of research is digital dermatitis, which is an infectious disease of the foot. Orsel’s work is looking mainly at feedlots with results expected to be released next year.

Digital dermatitis, also known as hairy heel warts or strawberry dermatitis, is becoming prevalent in feedlots. It might occur in pasture but is more often seen in confined environments such as dairy barns or feedlot pens where hygiene may be less than ideal.

It is a multi-factoral disease caused by bacteria and is difficult to treat.

It can occur when the skin is damaged, weakened or wet. Micro abrasions may occur and bacteria cause an infection of the skin. It changes the stance of the animal, which stands on its toe as it tries to get the weight off.

It can cause severe lameness and affect average daily gain.

The condition develops slowly and intervention is difficult. There is no evidence that an injection of antimicrobials works.

“The challenge is the infection is in the skin where antibiotics don’t get to where it needs to be,” she said.

Animals may be misdiagnosed, and the producer will suspect footrot.

“People should spend time on diagnosing correctly. In a feedlot it is different, but if you have valuable bulls, you have to diagnose and really look at the foot to see if it is in the foot or is it in the leg, muscles or joints.” Orsel said.

Clean, dry pens help keep out the disease, while walking in mud weakens the skin.

“If you have well-drained feedlot pens you will not likely see DD,” she said.

Some affected animals appear lame while others have a small lesion and struggle to walk. The animals could end up being shipped. They are not usually compromised and are eligible for transport.

Locomotion score systems are also available. The pharmaceutical company Zinpro has developed a simple-to-use guide to identify animals that are affected on a scale of zero to three.

“We need to identify the animals that need intervention,” Orsel said.

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