There are few if any diseases in dairy cattle that impact the performance, profitability and welfare of animals more than lameness. Indeed, it justifies a conscious effort on the part of every dairy to invest whatever time or effort is needed to optimize foot health. Effects on performance Lame cows are less competitive at the feedbunk, when choosing a stall or when involved in aggressive interactions with other cows. Add to this studies that suggest pain alone is sufficient to decrease feed intake, and it’s not hard to see why milk yield is reduced by lameness.

Despite the fact that most would expect a reduction in milk yield, relatively few U.S. studies have actually documented these effects.

A Cornell University study found that milk yield was reduced two weeks before and three weeks after lameness was detected in cows. A Florida study of cows affected with foot rot determined that mean milk production was decreased by 10 percent (1,885 lbs per cow) compared with unaffected animals.

This study also found that of cows affected, 80 percent were in early lactation, and of those, 60 percent were culled before completing their lactation.

Finally, a California study demonstrated that as locomotion score increases (i.e., severity of lameness increases), milk yield decreases. These studies support real-world observations that lameness has significant effects on milk yield in dairy cows.

Reproductive performance is also negatively affected by lameness. A United Kingdom study of 427 cases of lameness from 17 herds found an extension in the intervals between calving to first service of four days, and calving to conception of 14 days. Pregnancy rates to first service were 46 percent in lame cows compared to 56 percent in non-lame cows.

Services per conception and overall cull rates were increased in non-lame versus lame cows from 1.72 to 2.14 and 5 percent to 16 percent, respectively. A Florida study observed that lameness increased the calving to conception interval in affected cows from 100 days to 140 days in cows with claw lesions and as much as 170 days in cows with multiple foot lesions.

Another Florida study by Melendez et. al., found that cows becoming lame within the first 30 days of lactation had lower conception rates (17.5 percent versus 42.6 percent), lower overall pregnancy rate (85 percent versus 92.6 percent) and a higher incidence of cystic ovarian disease (25 percent versus 11 percent).

While many of the effects of lameness have been assumed to be indirect, a Florida study by Garbarino et. al., demonstrated direct effects on the ovary and thus ovarian activity resulting in lame cows having 3.5 greater odds of experiencing lengthened estrous cycles as compared with non-lame cows.

These observations were corroborated by Morris and Walker, who found that lame cows were less likely to ovulate as compared with non-lame cows. And finally, a study by researchers in India found that although estrus duration was similar for lame and non-lame cows, the intensity of estrous activity was significantly subdued in cows exhibiting lameness.

There is little question that lameness has dramatic effects on animal performance and longevity and that these have a huge impact on profitability.

Effects of lameness on profitability
If one were to pose the following question: “What is the most costly disease of dairy cattle?,” the most likely response would be “mastitis.” Indeed, there was a time in our history where no one would dispute that the high prevalence of subclinical mastitis made this disease the most costly.

However, we’ve made significant progress in the dairy industry by addressing subclinical mastitis problems, particularly that caused by Streptococcus agalactiae. Post-milking teat dipping and dry cow therapy have virtually eliminated this pathogen from most herds. Today, the answer to this question is more likely “lameness.”

Calculations by Dr. Chuck Guard from Cornell University indicate that, on an individual cow basis, lameness (at $478 per case) and left displaced abomasum (at $489 per case) are the most costly disease disorders. Mastitis (at a cost of $262 per case) ranks fifth behind retained placenta/metritis (at $325 per case) and milk fever (at $284 per case) as the most costly diseases of dairy cattle.

However, when the economic impact of these diseases is computed on a herd basis (that is, cost per 100 cows), nothing rivals lameness as the single most costly disease of dairy cattle. Lameness incidence rates of 30 to 50 percent or higher, as documented in several studies, has replaced mastitis as the most common and costly disease of dairy cattle.

Effects of lameness on animal welfare
The primary concerns in animal welfare typically include three basic questions: Is the animal functioning well (in other words, is it producing well)? Does the animal have pain or is it distressed? Is the animal able to express or perform natural behaviors?

For example, consider lameness in the context of these questions and one can see that we fail to achieve the objectives of good welfare by any of these measures. As pointed out earlier in this article, lameness affects the animal’s ability to function; it reduces milk production and reproductive performance. Lameness causes pain, as exhibited by an altered gait and reduced feed intake.

And finally, lameness interferes with the animal’s ability to express normal behavior; lame cows don’t move about freely or confidently and they interact less with herdmates in activities such as estrus behavior or social interactions.

No one should underestimate the impact of lameness on performance, profit and welfare. If you haven’t already, now would be a good time to review your foot health program. PD

References omitted due to space but are available upon request to editor@progressivedairy.com .

J. K. Shearer
Professor and Extension Veterinarian
Iowa State University
jks@iastate.edu