During the last few years, we have reduced the number and incidence rate of left displaced abomasums in our practice by 30 percent. The DA rate for the practice as a whole now stands at about 5.5 percent. While that is still above the suggested goal of 3 percent to 5 percent for each client herd, most are now within the target range.
Why the change? As we have accumulated more wisdom from research and on-farm experience, we have made a number of changes in the management of dry cows. These changes, when added together, have made a substantial impact on reducing DAs. Those changes include:
Focusing on forage fiber. A re-emphasis on the critical importance of forage fiber in the diet, as well as its role in maintaining the fiber mat in the rumen, has helped improve rumen health and digestion. The result has been less subclinical rumen acidosis. We now know that cows need greater energy and adequate glucose precursors for milk synthesis, beginning a few days before calving. One common way to meet this goal is to feed more starchy concentrates. But if this is done at the expense of maintaining the floating fiber mat in the rumen, the result can be greater declines in energy intake and more DA problems. The addition of straw or other coarser, more-slowly digested fiber to both lactating and dry-cow diets has proven to be of benefit in many herds. This probably improves the fiber mat, and, when fed for a long enough time during the dry period, may help to reduce insulin resistance. Insulin resistance is sometimes observed in early-lactation cows, particularly those with metabolic problems.
Adding monensin to rations. Monensin increases the production of propionate from rumen fermentation. It allows high-forage diets to produce more glucose precursors which, in turn, aid the dairy cow in navigating the demands of calving and early lactation.
Feeding protected choline. Rumen-protected choline does appear to enhance liver function and fat metabolism in early-lactation cows — particularly if fed during the dry period as well. While the research is much less conclusive than that for feeding monensin, most herds feeding rumen-protected choline have improved transitions of fresh cows.
Shorter dry periods. Instead of 60 days dry, more and more producers now use 40 to 50 days — or even as few as 30 to 40 days dry. This strategy allows for more productive days in the herd and eliminates the need for two dry-period diets. Instead, a single diet — higher in forage and lower in energy than typical transition diets — can be fed for the entire dry period. This simplifies management and may have health benefits. A perhaps unintended side benefit of this practice has been the reduction in social stress. More attention is being paid within the industry to the effects of pen moves and the effects these have on intake, performance, and disease — especially among cows of lower social rank. Reducing dry-cow pen moves by feeding one diet may promote better transitions all by itself. This has been an area of active research by veterinarians and nutritionists at the
. Universityof Wisconsin
The incidence of displaced abomasums in a herd is not the sole indicator of a successful transition cow program. However, if the DA rate in your herd is above 5 percent, you should re-evaluate your transition program. Work with your veterinarian and pay special attention to the issues outlined above, particularly fiber, energy, social stress and competition. Doing so could make a world of difference in your DA rate.
Brian J. Gerloff is a veterinarian and operates Seneca Bovine Service in Marengo, Ill.