Court Campbell, Ph.D., Land O’ Lakes
During the every day challenges of feeding cattle, you may not put much
thought into the sulfur level in your finishing diet, but sulfur can play a
major role in the performance of your cattle. Sulfur is a required mineral for
all animals, where it plays an important role in protein, fat, carbohydrate and
energy metabolism. However, this is one of those cases where more is not
always better. The suggested sulfur requirement of cattle is .10 - .15%. Dr.
Richard Zinn at the University of California recently obtained some interesting
results when he fed diets containing sulfur levels of .15 to .25%. When sulfur
exceeded .20% of the diet dry matter, dry matter intake and average daily gain
decreased while feed to gain increased. Also, they noticed that rib-eye area
decreased. High sulfur intake can lead to decreased dry matter intake and poorer
daily gain in cattle, possibly by causing a copper deficiency.
Sulfur can come from several different sources. Corn by-products such as corn
gluten feed, corn steep liquor and distillers grains tend to be high in sulfur.
We have known for some time that these by-products can contribute to
Polioencephalomalacia (Brainers, Polio), a disease created by a thiamine
deficiency. It appears that sulfur can destroy thiamine in the rumen. However,
studies evaluating thiamine supplementation under sulfate induced polios are
very inconsistent. Polios can also be caused by a drop in the rumen pH resulting
from acidosis. This drop in rumen pH can result in the release of bacterial
enzymes in the rumen that can also break down thiamine. At Land O Lakes, we
typically do not include thiamine in the diet, but rather, approach the problem
by stressing the importance of bunk management and recommending immediate
injectable treatment of individual animals showing signs of Polio.
Water can also be a main contributor to the total sulfur intake of cattle.
Many of our wells in Iowa range from 500 to 1,000 mg/liter of sulfur, with some
farms as high as 1,500 mg/liter. If feedstuffs used on the farm are high in
sulfur, a recommended maximum sulfate level in drinking water is 1,000 mg/liter.
This is a general recommendation, the level recommended for your farm will vary
depending on the sulfur content of feedstuffs used on your operation. The total
sulfur intake needs to be considered rather than individual sources. For most of
us, a reverse osmosis water purification system that can remove water sulfates
is cost prohibitive.
How then can we prevent the negative effects of high sulfate consumption by cattle? To date, there is little we can do economically. One way may be to consider use of ingredients lower in sulfur if faced with the problem of high sulfate water. One method may be the purchase of rural water depending on the proximity of the feedlot. Another may be by increasing the copper level in the diet. Increasing the dietary copper level may help alleviate some of the adverse effects of high sulfur water and/or feed by tying up some of the sulfur. Land O Lakes recently increased the copper level as well as other trace mineral levels in all feedlot supplements. This was done in order to help prevent trace minerals from limiting cattle performance and to also help alleviate some of the negative trace mineral interactions that can occur in the feedlot diet. For questions, please contact your local Land O Lakes Beef Specialist.