Nutritional Disorders

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ACIDOSIS

Acidosis is the most common nutritional disorder in the feedlot. A large amount of highly fermentable feeds, such as cereal grains, consumed in a short amount of time can result in the production of more lactic acid than can buffered by the rumen. This results in water from the circulatory system being drawn into the rumen (body becomes dehydrated) and pronounced changes in the blood Ph. Signs will usually be acute or sub-acute. Survivors of acute acidosis may have chronic problems such as fungal rumenitis, liver abscesses, bloat, and founder or laminitis.

Acute acidosis:
Animals that are not adapted to readily fermentable feeds are more susceptible to acidosis (sometimes called grain overload) than animals that have been carefully adjusted. However, even animals conditioned to full feed can be susceptible under some conditions such as feed changes and temporary restrictions in feed availability. Acutely affected animals will usually develop signs within 12-24 hours of overeating. They will be completely off feed, depressed and unwilling to move, weak, and dehydrated. They may appear blind, grind their teeth, grunt, and occasionally kick at their belly. Fullness and distension of the abdomen (rumen) may be observed. A foul smelling diarrhea may be observed unless the condition is so acute that the animal dies before it can develop
In severe cases animals will lie down, unable to rise. They generally lie quietly with their head tucked to the side. Body temperature may be subnormal and the pulse is weak. Death usually occurs within a few hours after the animals go down.
Animals that survive may suffer from damaged ruminal lining and destruction of rumen microflora leading to a fungal overgrowth of the rumen and death. Some deaths may occur as long as 3 weeks after a herd episode of overeating and acidosis. Less severe rumen lining damage may lead to liver abscesses and growth impairment. Laminitis, or founder, may follow acute acidosis, and evidence of subacute laminitis in the form of overgrown and deformed hooves may be present 30-60 days later.

Subacute acidosis:
Animals with less acute and severe signs may still eat but may not consume as much as normal or be off feed for only a short time. The only overt signs of subacute acidosis may be reduced gains and the presence of diarrhea in the form of flat gray stools. Because rumen lining damage may still occur in the absence of severe signs, these animals may develop chronic rumen damage and liver abscesses.
Weather conditions can cause fluctuations of intake of an otherwise acceptable ration. Storm conditions can cause cattle to consume a greater amount of feed before and after the storm. Muddy conditions which can alter feed intake. A drop in barometric pressure can indicate oncoming storm conditions. Conditions that promote intake of the regular ration in a shorter amount of time can cause acidosis. Hot, humid weather will cause cattle to eat a greater proportion of their feed at night, rather than during the day.
Improper mixing of feed can cause acidosis. As previously discussed improper bunk management can be a cause of acidosis. Only occasional cleaning of water troughs will also affect intake. Inclusion of an ionophore may help reduce intake fluctuations.

Treatment-Acute Acidosis:
If cattle are noticed soon after consuming large amounts of grain and before they drink water, problems may be avoided by keeping them away from water for up to 24 hours (Baker et al., 1983). Some common treatments are oral administration of mineral oil and/or sodium bicarbonate along with activated charcoal, anti-endotoxin therapy, and surgical emptying of the rumen in some cases.