01/14/2023
Thankfully, most calves are born unassisted, out of sight and out of mind. They nurse independently and quickly take their position as one of many productive herd members. But sometimes things don’t go as hoped, and the occasional calf is born with leg issues — namely contracted or lax tendons.
Contracted tendons exhibit as “knuckling over” with calves supporting themselves on their fetlocks or knees. The superficial deep digital flexor tendons are overly tight and shortened, forcing the tip of the toe back toward the heel.
Lax tendons are opposite to contracture and generally present as a lowered fetlock joint causing calves to walk on their heels and dewclaws with toes pointing upward.
POTENTIAL CAUSES UNCLEAR
“It’s important to clarify when we start talking about contracture and laxity, it’s more than just tendons,” says Dr. Andrew Niehaus, a professor of farm animal medicine at Ohio State University. “It’s also soft tissue problems, joint capsules contracted on the back side, or abnormalities where the bony structures aren’t formed properly leading to an inability to fully extend.”
He explains it’s difficult to identify these factors, especially in neonates, since the entire bone is cartilaginous and doesn’t accurately appear on radiographs. This makes it hard to detect if the articular surfaces are formed correctly.
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While Niehaus admits the possibility of a congenital defect relationship, he doesn’t consider tendon issues highly related to complications such as cleft palate, heart defects, curly calf or dwarfism. For those animals identified as having a congenital connection, he says there’s still an unknown element in understanding how and why they happen.
Niehaus says it’s not known exactly what causes these conditions, although, for contracture, popular thinking points to excessively large calves in utero forced into an overly tight space without the ability to stretch their legs in key stages of development. The size relationship of fetus to dam is a potential culprit when the uterine environment is too small for the matching calf.
He notes nutrition during gestation is often overlooked as a potential cause of both conditions, particularly laxity. When females are pushed in the last trimester with too much protein and energy, developmental problems in the joints and bones may appear. However, producers should also ensure they’re feeding adequate vitamins and minerals. For example, in some areas selenium is lacking, causing deficiencies to show as general weakness.
“Other causes of laxity are a little harder to pin down,” he says. “They tend to be more related to muscle weakness than tendons, but we don’t have a firm grasp on its pathogenesis.”
TREATMENTS
For those affected by contracted tendons, especially with milder cases, Niehaus believes the first line of defence should be time and exercise. Assuming the angulation isn’t severe enough to force knuckling over when weight is put on the legs, weight bearing will help stretch some of the soft tissues along with the tendons. If abnormalities exist in the joint surface, this exercise will help remodel the leg and foot to a more normal shape.
“This can be a challenge as it causes them pain, and they instinctively don’t want to use it,” he says. “But, if we get them up, force them to walk around while controlling their pain, and combine this with some physical therapy several times a day where we’re extending the legs as much as possible to stretch the soft tissues out, it’s beneficial.”
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Niehaus says splinting or casting the legs to extend the tendons and soft tissue is also an option, although splinting and decreasing the motion of the joint area will induce some laxity over time. Muscles attached to the tendons that in turn attach to the bone start becoming slightly weaker. As happens when humans don’t use a part of their anatomy, the area weakens over time.
As a last resort, surgery is an option to consider but this involves identifying the exact structures that are excessively tight, keeping the leg from extending and transecting them. This is also costly so value should be considered.
“Treatment avenues for laxity are more of a challenge,” Niehaus says. “With contracture, we need to stretch things out. But with laxity, how do we tighten it up? This can be a dilemma.” He believes exercise is also useful, although it could be argued it will stretch the soft tissues even more. His counterargument is exercise makes the animal stronger all around.
“The more exercise, the more muscle mass, and the more likely the calf will begin gaining strength and lose laxity.”
He adds splints may also be useful in these cases if the tendons have dropped so much the dewclaws are contacting the ground and causing trauma. But while splints will keep the structure more upright, they may still cause more laxity and perpetuate further weakness, he adds.
PAIN RELIEF
Niehaus says along with any selected treatment, newborns should receive selenium injections as deficiencies may cause orthopedic concerns, especially laxity. Some broad-spectrum tetracycline antibiotics have been regularly used with the belief they allow soft tissue structures to stretch but he says this has been proven largely ineffective.
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“If animals are in obvious pain, analgesics like Banamine (flunixin) or meloxicam are the best drugs to use. But they’ll only help if there’s discomfort.”
On a positive note, Niehaus stresses most of these contracted and lax tendons will stretch out and begin to strengthen quite quickly with affected calves making a full recovery. Some nursing care and effort may be required, but the result will usually be productive and viable animals.
– Bruce Derksen lives, works and writes in Lacombe, Alta. He has 30 years of experience as a hands-on participant in numerous branches of the Western Canadian livestock industry.
Thankfully, most calves are born unassisted, out of sight and out of mind. They nurse independently and quickly take their position as one of many
