The disease is common in stall-fed individuals. Consumption of indigestible food material, moldy and nutritionally unbalanced feed results in simple indigestion. It is clinically characterized by inappetance to anorexia, atony of the fore stomach and abnormal faeces.
Etiology: A common disease in both cattle and buffaloes,and is caused by consumption of indigestible feed material or ingestion of placenta by the cow after parturition. Some animals when fed in a group consume more roughage/ concentrate than accustomed to, may develop indigestion. Eating of damaged feed (spoiled, frozen, moldy or poor quality roughage) also results in simple indigestion. Indigestible roughage including straw, bedding material when fed during drought along with restricted intake of water is the common cause of indigestion. It also occurs in the animals fed an excess amount of good quality silage. Fatigue or stress of animals, which were held off feed for 12-16h or longer and then offered concentrate and roughage may lead to indigestion. A sudden change of feed formula or ingredients like change of oat to wheat or barley is a common cause of simple indigestion. Prolonged or heavy oral dosing of antibiotics or sulfonamides which inhibit the normal rumen flora also causes indigestion. Prolonged low grade hypocalcaemia also results in development of indigestion in bovines.
Pathogenesis: Rumen flora poorly adapts to the sudden change of feed and the change in ruminal pH affects the motility. Feeding of damaged feed leading to the atony of the rumen may have the same basis or may be due to some unidentified factors present in the feed. Simple accumulation of indigestible feed in the rumen may physically cause abnormal ruminal motility. Toxic amides and amines also cause ruminal atony. There is a sharp fall in the volatile fatty acids (VFA) in the atonic rumen which results in decreased milk production.
Clinical signs: Reduction in the appetite is the earliest sign followed by drop in the milk yield. Animal is depressed and rumination is stopped. There is decreased rumen movement, both in the amplitude and rate. Sometimes, rumen movements may be absent. The frequency of defaecation is reduced and faeces become dry. However, animal may have diarrhea after 24-48 h. There is no systemic reaction.
Laboratory diagnosis: Urine examination should be done for ketone bodies to differentiate simple indigestion from ketosis. Cellulose digestion takes more than 30 h and suggests inactivity of cellulose degrading bacteria. The sediment activity test can also be done on rumen juice. Floatation time is prolonged. Methylene blue reduction time and glucose fermentation tests conducted on rumen fluid also help in its diagnosis.
Diagnosis: Differential diagnosis should be made from traumatic reticuloperitonitis (TRP), acid indigestion, left side displacement of abomasum (LDA), vagal indigestion, and secondary ruminal atony due to hypocalcaemia, allergy and anaphylactic states. Appetite and milk production decreases in acetonemia (ketosis) and urine is positive fo r ke to ne b o d ie s . Rume n mo ve me nts a r e no r ma l b ut we a k. I n tr a uma tic reticuloperitonitis, there is painful grunt on palpation in the xiphoid region and atonic rumen with distension due to gases. There is fever and loss of appetite. In acid indigestion, rumen pH may be as low as 4.0. Animal is depressed, dehydrated with staggering gait. LDA is usually seen after parturition and rumen is smaller in size. In vagal indigestion, there is pasty and scanty defecation and increase in size of rumen is gradual. Rectal palpation is helpful in differentiation. Ruminal atony associated with hypocalcaemia, allergy and anaphylactic conditions responds to appropriate treatment.
Treatment: Symptomatic treatment and correction of feeding and environmental conditions result in recovery from the disease. Rumenotoric drugs are suggested. Magnesium salts (epsom salt), magnesium oxide or magnesium hydroxide can be given. Reconstitution of rumen flora is suggested. Acidifier (vinegar) or alkalizer is used to correct pH of rumen.