Use Caution When Feeding Dairy Cattle High Levels of Concentrate
Ensure forage alternatives are nutritionally balanced.
J. W. Schroeder, Dairy Cattle Specialist
Sometimes it is more economical for dairy producers to limit forage intake and feed concentrates more heavily. Drought generally requires producers to limit forage intake because of limited forage availability. The fiber content of the concentrate mixture fed on limited forage rations should be monitored closely to maintain cow health and milk composition.
If 3-5 lbs of hay-equivalent as hay-crop forage cannot be fed, it may be necessary to use a concentrate mixture with a minimum of 10-12 percent crude fiber as fed. This may be accomplished by using certain byproduct ingredients in the formula. These include: sugar beet pulp, wheat bran or mids, soybean hulls, corn gluten feed, brewers or distillers grains or malt sprouts. Due to their low soluble nitrogen levels, brewers or distillers grains are preferred when little hay is fed to dairy cows.
Most corn and protein supplement type feeds may only contain 5-7 percent crude fiber. In many cases only maximum crude fiber guarantees are given on tags for manufactured feeds or ingredients, so testing to determine fiber level may be necessary.
Buffers may also be considered if milkfat test depression occurs on limited forage diets. The inclusion of the following may be helpful: sodium bicarbonate at 1.0-1.5 percent, magnesium oxide at 0.5 percent and sodium bentonite at 2-3 percent of the concentrate mixture or finished feed. Always check the particle-size on silage or haylages if little or no hay is fed and fat tests are low.
Milkfat tests that run 0.3 percent below or above breed average may indicate that the cows are metabolically abnormal. The problem should be addressed since health and reproduction also may suffer. If necessary, increase levels of normal forage and reduce concentrate intakes appropriately. Most cows cannot maintain normal milk fat levels if concentrate intake from all sources (mixtures, top-feeding, etc.) exceeds 2.5 percent of bodyweight daily on an air-dried basis.
Whenever rations fed vary appreciably from the usual, it is more important than ever to test forages and obtain professional help with nutrition balancing. Nitrate and sulfur tests should also be obtained in appropriate situations, especially when forages have been grown and harvested during drought. Work with your nutritionist to balance rations with available feed stuffs.