Geni Wren In the past, cattle producers have opted to place greater emphasis on selection for factors such as milk production or fecundity versus structural soundness in dairy cattle. “Pure-bred cattle breeders may have a greater concern about potential lameness conditions, but have very little specific information on how to avoid these problems since some conditions are so widespread and also complicated by other etiologic factors (i.e. corkscrew claw),” explains Jan Shearer, DVM, MS, Iowa State University. “When producers or breeders tend to emphasize longevity in their breeding programs they pay closer attention to conformation of feet and legs.”
Some of the congenital defects observed in cattle have more than heritability as an underlying cause. Research suggests that the heritability of sound foot and leg structure is low, Shearer notes. “It takes a long time to correct conformational issues by improvement in breeding programs even when there is reliable information on bulls. And, while we tend to place a great deal of emphasis on bull selection, if the cow has lousy foot and leg structure, progress toward improvement will be slow. It is important to consider her contribution to the problem.”
Post-legged animals tend to have reduced longevity because many are at greater risk of degenerative joint disease (DJD) because of their conformation. “This is most surely a welfare problem and is not uncommon with certain club calf type bulls that produce great club calves, but animals that don’t fit most commercial cow-calf operations because they are prone to DJD and other lameness related problems,” Shearer says.
Spastic paresis is a neuromuscular disorder that sporadically occurs in beef, dairy and crossbred cattle. The disease is characterized by hyperextension of the limb followed by a spastic contraction of the gastrocnemius muscle. The disease is usually detected within a few months of the calf’s life and it gradually worsens over time. One or both of the rear legs may be affected. “There are methods to correct this condition surgically, but it is highly questionable if such procedures would be practical, and in addition, one should be cognizant of the hereditary implications,” Shearer says.
He adds that because of its sporadic occurrence, it is difficult to avoid reproducing some of these by searching the backgrounds of bulls or cows. In most cases, this information isn’t known or if known may not be recorded. “One reference suggests that even though the disease is known to be inherited, it shouldn’t limit bulls with high genetic merit because many believe that other environmental factors are likely to influence its occurrence,” Shearer says, “but this is indeed a controversial opinion.”
Shearer says there are a number of other congenital conditions that he would place under the heading of non-specific joint rigidity that are likely congenital defects with multi-factorial etiology.
Read an article on beef and dairy heifer lameness in Bovine Veterinarian here.