What are the prevention methods for abomasal displacement in dairy cows?

Under normal circumstances, the abomasum of a dairy cow is located on the right side of the abdominal cavity, with the left side adjacent to the rumen. However, due to certain internal or external causes, the normal position of the abomasum changes abruptly, either lying below the rumen or shifting to the left side of the rumen, all of which can cause symptoms such as complete loss of appetite, digestive disturbances, abnormal defecation, rumen bloating, and abdominal pain in dairy cows. This is abomasal displacement.

Abomasal displacement in dairy cows generally occurs in cows around the time of calving at the 4th to 5th parity. It is related to nutritional deficiencies before calving, changes in the cow's posture, and other factors. Under the combined effect of these factors, gastrointestinal motility declines, the function of smooth muscle becomes disordered, and the rumen becomes empty, thereby causing the normal position of the abomasum to change. The incidence of abomasal displacement in high-yielding dairy cows is generally 3%.

Clinical symptoms: Affected cows often show intermittent anorexia, and some refuse concentrated feed but can still eat a small amount of silage and hay. Body weight decreases, the animal is depressed, and body temperature, respiration, and pulse are mostly near normal, but milk production performance declines. Defecation is reduced and hard, with mucus on the surface; some affected cows have diarrhea, with soft, pasty feces. Because the rumen is pushed to the inner side, a flat-shaped swelling appears on the left abdominal wall. Rumen motility is weakened, and the number of rumen contractions decreases or even disappears. Affected cows show progressive exhaustion, prefer lying down and are unwilling to walk, and often adopt a lying posture. Below the line from the left hip joint to behind the elbow, a tinkling sound and a dripping sound from within the abomasum can occasionally be heard. By combining percussion with auscultation, a metallic echoing sound (steel pipe sound) can be heard at the left second-to-last and third intercostal spaces.

Preventive measures: Effectively ensure an adequate supply of total dry matter in the dairy cow's diet, with the proportion of roughage not less than 40%, and ensure the “roughness” of the roughage, preventing it from being ground too fine, and it is even less suitable to make it into pellets; in the late dry period, control the cow's calcium intake so that it does not exceed 0.4%-0.5% of dry matter, or a daily intake of 53 grams, or feed the dairy cow 200 grams of anionic salts to reduce the occurrence of hypocalcemia and milk fever; from the dry period to calving, the increase in concentrated feed and changes in the diet should not be too rapid, and there should generally be a 7-10 day transition period; in summer, do a good job of heat prevention and cooling for dairy cows to prevent the adverse effects of heat stress on dairy cows: frequently observe the cow's health and feeding and rumination conditions, and measure the cow's body temperature, respiration, and pulse; inspect defecation and urination, and if an infectious disease is found, treat it promptly; ensure that dairy cows have sufficient space for eating and drinking, and prevent the herd from being too crowded. At the same time, always keep the feed trough, cow bed, water trough, and exercise yard hygienic, and ensure that dairy cows have good conditions for eating, drinking, and ruminating.