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Animal Welfare and Claw Diseases

by, Chuck Guard, DVM, PhD, Ambulatory & Production Medicine Clinic, Cornell University, Ithaca, New York
Presented in Slovenia at International Ruminant Lameness Symposium 2004
Printed in 2005 Hoof Health Conference Proceedings

There are 3 areas of concern regarding the welfare of domestic ruminants and claw diseases. These are the prompt treatment of affected cattle to promote healing of the disease, the relief of pain due to the disease, and the prevention of cases of lameness by whatever means are appropriate. Each concern will be addressed individually with the understanding that they are interrelated. I will use cattle for most of my examples throughout the paper with the understanding that other ruminants merit similar considerations.

Detection and Treatment of Lameness
Prompt treatment of lame individuals requires several steps. First the detection of the disease or lameness in the affected cow must take place. Herd managers carry the responsibility for establishing systems for detecting lame cattle. In small herds and flocks the responsibility often is solely held by the owner but in larger units the complexities of labor management and delegation of duties often place herd managers or other workers in charge of detection of lame cows. For most herds and flocks the detection of lameness is done by observing the animals walk. For dairy cattle observation may be done at milking time for parlor systems or by moving through the pens or corrals of cattle at other times when the cattle are active. For tied cattle observation may occur during exercise periods. If there are no exercise periods it is sometimes more difficult to detect mild or subtle cases of lameness. For beef cattle on pasture stockmen generally move through the cattle at some interval to check for general health conditions including lameness. Confined beef cattle are usually inspected intensely by cowboys on horseback or other caretakers at least daily. All these methods of detection rely on the judgment of an individual who accepts the responsibility of identifying lame animals. With millions of such people in this role in the world there is certainly a wide variation in the definition of lameness and the sensitivity of the test employed. What this means from the animals perspective is a variable degree of lameness or duration of disease before an intervention is chosen. We must realize that this variability in detection sensitivity and timing represent welfare problems for lame animals. Certainly there are owners and managers who are very astute in identifying lame members of their herds and flocks. However, surveys done in both the United Kingdom (Mill 1994, Whay 2002b) and the United States (Wells 1993) have pointed out the apparent insensitivity of farmers to the degree of lameness that could be documented in their dairy herds. Too often the ordinary which includes lame individuals is judged to be normal and the lame individuals are allowed to suffer without human assistance. In my opinion, the covenant we have with our domestic stock is to help heal their diseases when possible and to provide euthanasia when we can not.

The choice of intervention once the animal has been declared lame includes as much variation as the reliability of the detection method. Treatment for lameness is done by everyone including farmers, their employees, hoof trimmers, veterinarians in general practice, and veterinarians who specialize in the affected species or who are hospital-based clinicians with specialized resources. Furthermore, farmers often receive advice about treatments from neighbors, truck drivers, other farmers, and now via the internet. A great part of this resulting variability comes from a lack of knowledge of the diseases causing lameness and in less developed regions lack of resources for restraint or therapy. It is of grave concern that treatments are sometimes inappropriate and may in fact create more pain or tissue damage than the original disease. These inappropriate treatments are in no way confined to the less developed regions of the world.

Technological means of detecting lameness are used by some farmers. The system employed most commonly is used in dairy cattle and consists of either pedometers worn on a limb at the fetlock joint or activity monitors worn around the neck. These systems are primarily employed to detect estrus via increases in steps or head bobs compared to an individuals rolling average. They have the secondary capacity to detect decreases in activity associated with lameness. Companies marketing these systems have not stressed nor developed their software to promote lameness detection. In fact, the sensitivity of the detectors to motion sometimes results in higher activity scores for cows that limp badly because they generate more exaggerated movements of the sensor. To the author’s knowledge no systematic evaluation of movement detectors has been made with regard to lameness detection. Herds with activity monitors almost always have automatic milk recording. These data allow the cows who have a significant drop in milk production compared to their rolling average to be identified and examined. If the problem with the cow is lameness, it is usually identified during the general examination that is standard procedure in many herds with automatic milk recording, even if activity monitoring is not part of their systems.

An alternative technology for detection of lameness is under development for commercial application by Bou-Matic company of Madison, Wisconsin, USA. Some research about this system has been presented in previous meetings of this organization. The detection of lameness relies on measuring signals from a load sensing platform that is placed in the return alley from the milking parlor. Computer manipulation of signals from the sensors can estimate load placed on each leg and stride characteristics. Deviations from normalized data are used to identify cows with lameness. To the authors knowledge this system has not been deployed on commercial farms. Other systems not even dreamed of yet by engineers will probably be developed in the near future. One possibility is for video recognition software such as is used in security monitoring to identify individual cows within a herd and further characterize their gait in some fashion that would permit identification of lameness. The author has had discussions with a software company that indicate the feasibility of this method.

There clearly is a role for veterinarians, livestock specialists, and extension personnel to help educate farmers and their employees about lameness recognition. This notion seems so simplistic but the performance of many current herd managers in lameness detection is so poor that a need clearly exists for more effort. Secondly, appropriate treatments should also be taught so that relief of pain and suffering might be as prompt and effective as possible. Since treatments are delivered by veterinarians, farmers, and hoof trimmers, all these groups should be included in efforts to deliver more knowledgeable interventions. There would certainly be disagreement about the final details of appropriate therapy for even many common conditions among the attendees at this meeting. Perhaps we should encourage more clinical research in the areas of therapy for the most common conditions.

Pain Management for Lame Stock
The science of pain management has made many advances in human medicine in recent years and includes books and journals devoted to the subject. There have been some symposia in veterinary medicine devoted to pain management but their focus has been companion animals not ruminants. A very recent textbook on pain management for animals is quite comprehensive but offers little for ruminants (Gaynor 2003).  The methods of pain management for lameness problems involve both the specific therapy for the primary problem, may involve pain avoidance by methods such as hoof blocks and housing in more comfortable or protected locations, and specific pharmaceutical agents for amelioration of pain (O’Callaghan 2002). Dr. Becky Whay provided a concise review of the pathophysiology and treatment of pain at the 12th International Symposium on Lameness in Ruminants (Whay 2002a). The first options should be part of the general philosophy of lameness treatment. The intervention should relieve the pain of the primary condition whenever possible. Changing the housing to a hospital pen or other environment where competition for food, water, and a comfortable place to lie are minimized should also be a standard part of lameness therapy. We are aided in our understanding of the physiology of pain in lame cattle and the usefulness of pharmacological intervention by the work of the group in Liverpool (Whay 1998)Specific drug therapy for pain management depends on drug availability which varies greatly around the world. In the United States the only drugs available for pain management are 2 corticosteroids, dexamethasone and isoflupredone, flunixin meglumine, and aspirin. Only aspirin is specifically labeled for pain control and thus veterinary prescription is required for use of the other drugs in pain management with associated withholding of meat and milk from market channels. Registration requirements for animals that produce food products are very restrictive in the United States and apparently somewhat less so in other countries. Flunixin meglumine may be used in special circumstances in dairy cattle in the United States if a set of regulatory criteria are met. The enthusiasm with which animal owners and their veterinarians employ such drugs are often linked to their cost and their requirements for withholding milk or meat from the market. In my opinion, such drugs are not routinely used for lame cattle due to the reluctance to advocate their use by veterinarians who are sensitized to the owners concerns about treatment costs and subsequent drug-dependent restrictions on marketing options.

Veterinarians treating lameness in the United States are, in general, probably not advocating treatments aimed at pain relief. Why? First, there is no educational effort in the general veterinary curricula of the colleges devoted to the topic of pain in food animals or in its management. Second, cost of therapy is always on the mind of veterinarians who perhaps have an overriding concern for treatment costs. We have been investigating the cost of lameness in dairy cattle for several years. The average cost of treatment including all labor by farm workers is $26 per case which is about 10% of the total cost. Typical drug cost and associated milk discard for 3 days of therapy with flunixin meglumine would add $61 to the treatment cost. The cow would have to make more milk than otherwise to repay the investment in the drug treatment and this would be about 800 lb of milk at current prices in the USA. We do not have any data on the improvement in recovery from lameness with treatment for pain with drugs such as flunixin meglumine. Veterinarians and farmers alike in our dairy culture would hope to justify the treatment of pain on economic grounds. Is this ethical? Should pain relief be attempted regardless of economic consequences? In reality, if veterinarians prescribed expensive treatments for lameness they would likely not be asked to examine or treat future cases unless the treatments were clearly superior to historic treatments that did not treat pain. In the system of drug control in the United States aspirin may be used at the discretion of the farmer. If aspirin could have similarly beneficial effects to flunixin it might be more acceptable since a 3 day course of treatment would cost $30 and only require 400 lb of extra milk to balance that cost. Corticosteroids require no milk withhold in our regulations. Thus, if their use would be beneficial and not harmful to pregnancy, the cost would be only $3 for 3 days treatment which almost any farmer would tolerate. I am unfamiliar with drug use practices or regulations in other countries so can not discuss pain management in those jurisdictions.

Animal Welfare via Disease Prevention
Prevention of diseases causing lameness can hugely contribute to animal welfare. Changes in management or housing or outside environmental management are the primary tools for lameness prevention. It is beyond the scope of this paper to discuss all the known risk factors in detail. Feeding management is considered by many to have a central role in preventing ruminal acidosis and subsequent laminitis/coriosis. Housing design and maintenance have many influences on animal health. Walking surfaces and resting places are very influential in predisposing to claw horn diseases. Manure management and foot bathing control infectious digital diseases. Outside the barn the conditions of corrals, animal walkways or lanes, and around feeders or waters can influence both claw horn and infectious diseases. Good designs and management practices have the ability to greatly minimize lameness problems at the herd level. Achieving a low incidence of lameness should be a prominent concern in establishing design criteria for new or renewed facilities. Once facilities are in place the management of them is equally important for successful control of lameness. Once again, the role of veterinarians and livestock management advisors can be to educate producers to establish management regimes that reduce the known risk factors for digital diseases. Comfortable lying areas or stalls, minimizing time standing on concrete, clean and dry alleys, diets that do not cause ruminal acidosis, regularly scheduled hoof trimming, non-injurious cow lanes and control of mud around feeding and drinking places for cattle kept outside will all contribute to producing a lower incidence of lameness. Many producers have operations that violate more than one of these guidelines for lameness prevention. Since many of these same producers seem immune to welfare concerns perhaps economic arguments explaining the cost of lameness will help persuade them to adopt more cow-friendly practices and create fewer lame cattle.

Remaining Questions
In light of the apparent inability of farmers to adequately recognize lame cattle in their herds, perhaps the most pressing question is, why not? Furthermore, what can the informal group of enthusiasts attending this conference or reading these proceedings do to improve the detection and treatment of the lame individuals which inevitably populate all herds? Can we define best management practices for treatment of individual cases of lameness? Will pharmaceutical companies invest in registration for effective drugs to treat the pain of lameness? Can we convince farmers of the ethical imperative to acknowledge that lameness means pain and without pain management we are not fulfilling our commitment to our domestic animals? 

References

Gaynor JS, WW Muir. 2003. Handbook of Veterinary Pain Management. 452 pp. Mosby

Mill JM, WR Ward. 1994. Lameness in cattle and farmers’ knowledge, training and awareness. The Vet Record. 134:162-164.

O’Callaghan K. 2002. Lameness and associated pain in cattle – challenging traditional perceptions. In Practice. April:212-219.

Wells SJ, AM Trent, WE Marsh, RA Robinson. 1993. Prevalence and severity of lameness in lactating dairy cows in a sample of Minnesota and Wisconsin herds. J Amer Vet Med Assoc. 202:78-82.

Whay HR. 2002a. A review of current pain management in ruminants – the lame cow model. pp. 131-138. Proceedings of 12th International Symposium on Lameness in Ruminants, Orlando, Florida, USA

Whay HR, DCJ Main, LE Green, AJF Webster. 2002b. Farmer perception of lameness prevalence. pp. 355-358. Proceedings of 12th International Symposium on Lameness in Ruminants, Orlando, Florida, USA