Maintaining the health of the herd is a priority for all goat producers, dairy and meat alike, but Caprine Arthritis Encephalitis (CAE) continues to threaten the productivity and long-term health of goat herds across North America.
In a simple sense, CAE is a viral infection that surfaces as a form of arthritis. It impacts adult goat mobility and quality of life. There is no known cure for CAE, so proactive herd monitoring and careful management are required to reduce the incidence and prevent transmission of the disease.
Physical symptoms of CAE can vary and infections showing no symptoms often go undetected. Cases of CAE may result in a harder-than-normal udder, mastitis, oversized and/or knobby knees (not due to a specific injury), a decrease in or complete loss of milk production, significant weight loss and even severe or fatal pneumonia.
As awareness and concern for CAE has grown, producers of breeding stock genetics have been pushed to establish and maintain CAE-negative herd status, ensuring that herd bucks and does do not test above laboratory specified danger zones of antibodies associated with the disease. Protecting long-term herd health should be a high priority in dairy and meat goat herds focused on long-term profits. Eradicating CAE once it has entered the herd is labor and cost intensive, but developing and implementing CAE prevention measures before kidding season is a step in the right direction.
CAE prevention must begin at birth. Newborns should be separated from their dams immediately after birth, before the doe is allowed to lick or clean the kid, and before the kid is allowed to nurse. Newborns should be fed heat-treated colostrum or a colostrum replacement within one to four hours of birth. A high-quality colostrum replacement formulated specifically for goat kids is ideal, but heat-treated colostrum from a CAE negative doe can serve as a good alternative for proactive CAE prevention. It is important to follow proper procedures to ensure that other protective antibodies and nutrients are not destroyed by the heat-treating process.
Since the most direct infection route for CAE is the transmission from doe to kid, infected colostrum and milk account for almost 90 percent of CAE infections. There are very few, if any reputable studies, which show that other body fluids such as saliva and blood can also spread the infection, but since this is an unknown aspect of the disease, it is wise for the owner to err on the side of caution. Proactive prevention using management tools such as kid-specific milk replacer and regular testing are significant in the battle to eliminate CAE in the herd.
Feeding a kid-specific milk replacer helps keep kids healthy and growing while hopefully preventing CAE by eliminating transmission of the virus through infected doe’s milk. Again, the most significant infection route for CAE is from mother to kid through infected colostrum.
After the first feeding of colostrum replacement, kids should be raised on a diet of high-quality, species-specific milk replacer, or pasteurized goat milk. The best nutrition source should be considered an investment in the herd. It is important to note that goat kids have higher nutritional needs than dairy calves, and should not be fed cattle milk replacers as a substitute for doe or sheep milk replacers.
"Feeding a kid-specific milk replacer is important to meet the unique nutritional demands of the young goat kid. Milk replacer formulated for other species does not provide the complete nutrient formulation that matches doe’s milk," said Dr. Tom Earleywine, Director of Nutritional Services at Land O’Lakes Animal Milk Products. "Feeding a nutritionally complete, kid-specific milk replacer that contains the correct balance of protein, fat and carbohydrates is necessary to meet the growing kid’s needs and may help them reach their full potential."
In addition to feeding a high-quality kid milk replacer, routine testing should be conducted to ensure that CAE stays out of the herd. A reliable ELISA test is a convenient, effective way to routinely monitor CAE in the herd. CAE testing can be efficiently conducted with pregnancy testing, immediately prior to kidding season.
According to Dr. Chuck Passavant, Senior Research Scientist and a CAE testing specialist with BioTracking LLC, goat producers should routinely test the entire breeding herd for CAE, ideally prior to kidding. Testing will help identify the majority of CAE-positive animals. If a goat has produced antibodies, it may have been exposed to the disease and is in the process of fighting the virus. Goats that test positive have the potential to spread CAE to others in the herd, even though there are not currently tests to determine this possibility. The ELISA test is generally recognized as the most reliable CAE test method and it is offered by several diagnostic laboratories around the country.
Passavant said that CAE testing on kids younger than seven to nine months of age was not effective because "false negatives" are possible, especially in young goats. Older goats with a dormant infection are likely to test false negative, and there is potential for infected kids to show a false negative due to testing before their immune system is able to recognize the virus and produce the proper antibodies. Kids may also test false positive if they are consuming pasteurized milk or colostrum from CAE positive dams as antibodies in the milk, absorbed through the intestine and into the serum, take several weeks to clear from their serum post-weaning.
With the variants in testing results, the best way to combat CAE in the goat herd is to practice prevention with a good management program. For more information about CAE prevention measures, visit the Land O Lakes Milk Replacer website.
Washington Animal Disease Diagnostic Lab. "Update on Caprine Arthritis Encephalitis (CAE) Virus, Washington State University." College of Veterinary Medicine. 1 Feb. 2011. Web. 29 July 2011.
Department of Pathology (Tarpley, Latimer) College of Veterinary Medicine, University of Georgia, Athens, GA 30602-7388. "Caprine Arthritis-Encephalitis Virus." Web. 29 July 2011.