Transition Cows and Displaced Abomasums

The majority of displaced abomasums (DA) occur during the first three weeks after calving. The abomasum is the last of four stomachs found in the ruminant digestive tract. It is similar in function to the single stomach found in monogastrics including humans. The abomasum is found on the lower, right side of the cow but in DAs the abomasum loses its muscle tone, fills with gas and subsequently floats out of place and most commonly ends up on the left side of the animal(LDAs). There is no single cause of LDAs. A number of nutritional as well as non-nutritional causes contribute to its incidence.

Non-nutritional causes of LDAs include fetal growth, mechanical stresses such as calving or injury (eg. struggling in a stanchion), genetics, lack of exercise and stress. Other metabolic diseases, such as ketosis and milk fever, or simply being off feed, can predispose cows to displaced abomasums.

High grain intake and insufficient fibre in transistion diets are the main nutritional factors causing LDAs. High grain diets increase volatile fatty acid production in the rumen. VFAs act on the smooth muscle in the abomasal wall and decrease its motility. Gas formation increases and the abomasum floats out of place.

Low feed intake and sudden changes in a feeding program, such as increasing grain too rapidly, increase the risk of LDAs.

Proper transition feed management can reduce the incidence of LDAs. Consider the following practices:

1. Provide adequate amounts of effective fibre in transistion diets. This means a minimum ADF of 21% in ration dry matter, a minimum 40:60 forage: grain ration in the lactation diet, and adequate effective fibre (10% of particles over 1.5 inches long).
2. Supplement the fresh cow TMR with 5 pounds of long hay per cow daily.
3. Concentrate intake should not exceed 0.50 to 0.75% of body weight at calving time.
4. Increase grain intake after calving by 1 lb per day until desired intake is reached.
5. Feed forage before grain if not a TMR herd.
6. Grain intake should not exceed 5 - 7 lbs per feeding.