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The saying goes that too much of a good thing is not good at all. In the case of acidosis, this is indeed true. Acidosis is a common occurrence in animals exposed to an abundance of palatable feed and that had ingested too much highly digestible carbohydrates (or sugar).
According to Dr Schabort Froneman of Zoetis, the most common cause of acidosis is the sudden excessive intake of grain, meal or crushed maize, silage (especially if poorly fermented), by-products of brewer’s grain, potatoes, apples or peaches (high sugar content), bread or molasses.
He explains that the micro-organisms in the rumen of animals grazing on grasslands, are not adapted to digest energy-rich carbohydrates. This excess of digestible carbohydrates sets the scene for the wrong type of micro-organisms to proliferate.
Consequences and complications
Acidosis has several unpleasant consequences. Lactic acid burns the rumen wall and causes inflammation of the rumen. The lactic acid is consequently absorbed into the bloodstream, in turn leading to metabolic acidosis.
Water from the body also collects in the rumen and can lead to dehydration. Often, rumen motility will stop completely and, along with an increased rate of fermentation in the rumen, will lead to bloat. Adding to the negative effects is the production of an enzyme that breaks down thiamine, leading to a vitamin B1 deficiency and nervous system symptoms.
If the animal is not treated at once, bacterial or fungal infection of the rumen, liver and even lung abscesses can occur. Finally, upon death, certain bacteria release a toxin that causes shock, organ damage and laminitis.
Acute versus chronic acidosis
Dr Froneman says it is essential to distinguish between acute and chronic acidosis. Acute acidosis entails the once-off excessive intake of carbohydrates. Symptoms include suppressed appetite, a drop in milk production, yellow to grey watery diarrhoea and a drop in rumen motility. In severe cases animals will exhibit tremors, rapid breathing and pulse, bloat, abdominal pain, inflammation in the hooves, and they may lie down and struggle to get up.
Acidosis has several unpleasant consequences. Lactic acid burns the rumen wall and causes inflammation of the rumen.
Chronic acidosis, on the other hand, is a syndrome that occurs when warm rations containing too much energy and too little roughage are fed. This is often seen in feedlots and dairies where animals are fed in a bid to increase production.
“Although chronic acidosis does not usually lead to death, the outcome is usually inefficient production,” he says. Symptoms of chronic acidosis include a drop in milk production and butterfat, declining feed conversion and weight gain in feedlots, abattoir reports indicating a high percentage of liver abscesses, animals with long, grown-out hooves that appear to have trouble walking, ketosis, diarrhoea and bloat.
According to Dr Johan van Rensburg of ABE Biotech, the first step is to remove the animals from the feed source and take out the very sick animals – treat them with an antacid immediately.
“In the initial stage of acidosis, they can be dosed with antacids or magnesium oxide. Although not ideal, bicarbonate of soda (two tablespoons in 200ml of water) can be given as an emergency measure. Activated carbon or PPR powder can also be used. The carbon prevents toxins from being absorbed into the rumen and intestinal tract,” he explains.
“Penicillin injections will help prevent liver abscesses. Vitamin B complex also helps support the liver in the processing of acids and toxins.”
Dr Froneman agrees and adds that animals should be treated as soon as possible after excessive intake. “Time plays a crucial role. Even when an animal survives an acidosis ‘attack’, potentially fatal complications may still occur. If animals ingest their normal amount of feed within three days after treatment, the producer can assume the prognosis was good.
“For the best results, call in the help of your veterinarian – especially where valuable animals are affected. The veterinarian will use a gastric tube to flush the rumen or possibly perform an operation in which the rumen is cut open and the contents removed.
“It is then replaced by new rumen content from a healthy animal, or a mixture of roughage soaked in warm water with added rumen stimulants. The veterinarian can also expand treatment to include antibiotics, anti-inflammatory agents, intravenous buffers and/or electrolytes.”
The secret to preventing acidosis is adapting animals by gradually exposing them to a high-energy diet, whether forage maize, complementary concentrate or a full ration. At the same time, enough roughage should be given. Dr Van Rensburg says probiotics containing Megasphaera elsdenii can be incorporated to make the adjustment even safer. – Koos du Pisanie, Stockfarm
For more information, contact Dr Schabort Froneman on 082 348 2306 or Dr Johan van Rensburg on 082 336 5498.