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The cost and incidence of dairy cattle lameness

Hoof health remains a significant, though usually underestimated, challenge on modern dairy farms. Dr. Chuck Guard of Cornell University has calculated that when all the costs are considered, lameness is the most expensive health problem that many dairies now face, surpassing even mastitis in both the average cost per case and the total cost per herd. Furthermore, cow performance and profits suffer well before the outward signs of lameness become obvious.

Fortunately, studies during the past several years have shed more light on both the incidence and the cost of lameness—especially from hoof disorders, which account for approximately 90 percent of lame cows. In addition, scoring systems are making it easier to identify lame animals early, so that cases can be treated, and underlying causes addressed, before the problems become severe.

Guard (1997) based his estimates of the cost of lameness on clinical observations and the records from 30 New York dairies. Although the exact figure will vary somewhat with factors such as milk prices, the average total cost runs between $300 and $350, he reported.

Dr. Jan Shearer of the University of Florida arrived at a similar estimate using Dairy Herd Improvement (DHI) data from the university's herd. Shearer (1998) estimated the total cost of lameness at $327 per case once he factored in reduced reproductive performance, lower milk yields, higher culling rates, discarded milk and the additional management required to care for lame cows.

Treatment, in fact, is the smallest component of the total cost of lameness, according to Guard. He has estimated it at $23 per case. Increased death losses, which Guard has placed at 2 percent, are also a comparatively minor part of the cost—$24 per case when spread across all lame cows.

Much costlier are the declines in reproductive performance and milk production and the increase in premature culling that accompany lameness. For example, Guard has estimated an extra 28 days open, for a cost of $56 per lame cow. Lower milk production, largely because of reduced feed intake, costs $67 per lame cow. This assumes 750 lbs of lost milk production—which Guard says may be conservative.

Finally, the single largest cost component of lameness is due to increases in premature culling, which add $176 per case. This was based on six additional culls per year, with a salvage-cow value of $540 and replacement cost of $1,200.

Incidence rates are equally worrisome. Based on the herds he has observed, Guard now estimates that 38 percent of the cows in an average herd have a clinical incident of lameness per year. Thus, the $346 average cost per lame animal reduces a dairy farm's income by $131 per cow when spread across the whole herd. In the University of Florida herd, DHI data showed that 35 percent of the animals were lame, for a total herd cost of $114 per cow in lost income. Expressed another way, lameness costs between $0.31 and $0.36 per cow per day.

For perspective, Guard (1997) estimated that clinical mastitis costs an average of $190 per case and has a whole-herd cost of $74 per cow, assuming that 39 percent of the herd must be treated for the disease (Table 1).

Other indications of the cost of lameness were apparent in research at Michigan State University, which considered the interaction between lameness and various reproductive endpoints. In this work, Sprecher et al. (1997) reported that lame animals were almost three times more likely than other animals to take longer than the herd mean for days to first service (Table 2). About 58 percent of the lame cows took more days than the herd mean to reach first service, compared with just 21 percent of nonlame animals. Lame cows were also more than 15 times more likely to be above the mean for days open— with 67.8 percent of the lame cows, but only 4.3 percent of their nonlame herdmates, exceeding the mean on this measure of reproductive performance.

Lameness also increased the risk of having more than the typical number of days in the breeding herd—65 percent were above the mean, compared with none of the nonlame animals. And lame animals were 9 times more likely to have more than the mean number of breedings: 39 percent required more than the mean, compared with only 4 percent of nonlame animals.

Ultimately, about 35 percent of the lame animals were culled for poor reproductive performance, compared with none of their nonlame herdmates. Statistically, this difference meant lame cows were 9 times more likely to be culled prematurely, Sprecher et al. (1997) noted. Regression analysis showed that lameness explained as much as 38 percent of poor reproductive performance, the researchers reported.

The expense of premature culling is especially high if the culling occurs before the cow has recouped her development costs. Cady and Smith (1996) noted that even in well-managed herds with high production and high net milk income, a cow generally will not produce enough net income to cover her development costs until she is six or seven months into her second lactation. In more typical herds, the average breakeven may exceed two lactations. Yet with a typical culling rate of 35 to 40 percent, a dairy herd turns over completely every 30 to 34 months. With marginal management, the break-even age already comes dangerously close to the average herd life of cows.

In the Michigan State work, the increase in involuntary culling began to occur well before signs of lameness were noticeable to an untrained eye. To better assess lameness, Sprecher et al. (1997) used a 1 to 5 scoring system to identify varying degrees of lameness in dairy cows.

The scoring system looks for two signs of lameness: an abnormal gait and an arched-back posture while the cow is standing or walking on a hard, level surface. Although an abnormal gait is more commonly recognized as a sign of lameness, the authors noted that the arched back has been associated with acute and chronic laminitis at least since Morrow (1966). The arched-back posture, in fact, appears in lame cows before abnormal gait, and thus becomes critical to early detection and treatment of lame cows, Sprecher et al. (1997) noted.

The five scores are defined thus:

Score 1: Normal. The cow stands and walks with a level back. Her gait is normal.

Score 2: Mildly Lame. The cow's back is level when she stands, but it arches when she walks. Her gait remains normal.

Score 3: Moderately Lame. The cow's back is arched whether she is walking or standing. Her gait begins to show abnormalities and is best described as short striding with one or more limbs.

Score 4: Lame. The cow's back remains arched at all times. The abnormality in her gait becomes more pronounced. It is one deliberate step at a time, and she favors one or more limbs or hooves.

Score 5: Severely Lame. The cow's back is always arched, and she demonstrates the inability or extreme reluctance to bear weight on one or more limbs or hooves. She may resist standing.

On most farms, a cow would have to reach a score of 4 or 5 before her lameness was recognized. However, Sprecher et al. (1997) reported that the declines in reproductive performance occurred by the time a cow had reached a lameness score of 3. As a result, the researchers suggested that score 2—when the only sign of lameness is an arched back while walking—is the critical point of intervention to forestall economic losses.

Sprecher et al. (1997) designed their scoring system to encourage use in commercial situations. Beyond assessing individual cows, it is important to track lameness on a herd basis as a management tool. Proper environment, nutrition and hoof care all promote good hoof health. Remedial actions could be as major as remodeling facilities or as basic as providing adequate fiber and supplemental biotin in the cow's rations.

Guard (1997) noted the incidence of lameness appears to be increasing as dairies expand and as tie-stall barns give way to freestall and drylot housing, where lameness will cause more pronounced declines in feed intake and thus milk production. Scoring an entire herd at regular intervals will enable producers and their advisors to treat individual cases but also to determine whether more basic changes are required.

References:

Cady, R.A., and T.R. Smith. 1996. P. 7. Economics of heifer raising programs. In: Calves, Heifers and Dairy Profitability, National Conference; Harrisburg, Pennsylvania. Northeast Regional Agricultural Engineering Service. 152 Riley-Robb Hall. Ithaca, NY 14853.
Guard, C. 1996. Laminitis in dairy cattle: Recognition of the disorder and management of the causative factors. Proc. Am. Assoc. Bovine Practitioners. 28:71.
Guard, C. 1997. The cost of lameness and value of routine hoof care. Proc. Hoof Health Conference, Batavia, New York.
Morrow, D.A. Laminitis in cattle. 1966. Vet. Med./Small Anim. Clinic. February, 138.
Shearer, J. 1998. Some ulcers, white line disease, and infectious claw disorders: primary causes of lameness in dairy cattle. Proc. Roche Dairy Nutrition Technical Workshop, Dana Point, California.
Sprecher, D.J., et al. 1997. A lameness scoring system that uses posture and gait to predict dairy cattle reproductive performance. Theriogenology. 47:1187.
Sprecher, D.J., and J. Kaneene. 1997. New lameness scoring for dairy cattle. Michigan Dairy Review 2(3):1.


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