Careful observation of livestock and range conditions can provide information useful in preventing death; thus, indications of ill health in live animals may aid diagnosis when dead animals are found. When the cause of loss is unknown or uncertain, a veterinarian’s assistance in diagnosing the cause of death may help prevent further losses. Diagnostic laboratories may help determine the cause of death; these facilities are available in all states. Some animal diseases can be transmitted to humans and proper precautions always should be taken to prevent exposure during carcass and tissue sample examination.
External Appearance of Animal and Carcasses
Although hair or fleece length and density varies with livestock breeds, healthy animals normally have a coat that is glossy from natural oils and is “live” to the touch; their skin is soft and flexible. In contrast, unhealthy animals have dry, dull coats that are harsh to the touch. Extended periods of poor health cause their skin to become dry and less flexible.
Coat condition is more difficult to evaluate in sheep since there is wide variation in fleece length, diameter and density in different breeds. There is also great variation, resulting from diet and nutrition, in the amount of natural oils in the fleece. Range type, vegetation and weather conditions also can cause marked differences in wool color and appearance. For example, extended wet periods, particularly in forested areas, cause fleece darkening. Also, unshorn sheep in late spring and summer may have a ragged appearance from some wool loss, particularly where they range in brush and lose wool on snags.
An alert appearance of the eyes and ears of livestock normally indicates a healthy animal. Sunken eyes and drooping ears indicate poor health. In fresh carcasses of healthy animals, the eyes fill the sockets and are not sunken from dehydration; however, carcasses dehydrate and decompose rapidly in temperatures above freezing.
Normally, livestock feces are relatively firm and dry. Exceptions include young animals receiving large amounts of milk and adult animals on lush, green forage. High quantities of concentrates also will cause soft feces. This should not be confused with diarrhea, an unhealthy condition resulting from excessive quantities of concentrates, certain infectious diseases or diseases caused by internal parasites.
Animals that die from causes other than predation normally die on their side or chest with their legs folded under them. Animals which get on their backs and die of suffocation are one major exception. This occurs most often in sheep attempting to scratch by rolling on their backs. Those with long, dense fleece may be unable to right themselves. In this position, gas cannot escape from the rumen, which distends and compresses the lungs, causing suffocation.
Another common cause of death is gas distention of the rumen (bloat) which may be caused by ingesting excessive amounts of grain or by feeding on alfalfa, clover and certain other plants. Bloat should not be confused with excessive carcass distention caused by gasses formed during decomposition.
Carcasses should be examined for abnormal excretions, particularly pus or blood, from body openings (the eyes, ears, mouth, genitals and anus). Live animals and carcasses should be examined by a veterinarian if such abnormalities exist or are suspected.
The carcass should be examined for skull fractures, broken bones and other wounds. The chest and stomach cavities should be opened to check for internal injuries and hemorrhage