A statewide drought that has pushed forage production below normal is endangering Utah cows, say two Utah State University professors.
Extreme dry conditions in many areas of Utah have created a feed stress that came after most cows had conceived, said James A. Bennett, animal science emeritus professor, and Norris J. Stenquist, Extension animal scientist.Bennett said many pregnant cows are now thin enough to make them highly vulnerable.
From now until calving, in order to nourish the developing fetus, he said the nutritional needs of a cow accelerate.
"Most of these cows will carry their calves to term, but clouds of danger will be hanging over them," he said.
One of the dangers of underweight cows at calving is greater difficulty in delivering the calf. Bennett said under these stressful conditions, the chances of the cow's dying during the birthing process increases. As well, most of the surviving calves will be smaller and less vigorous.
"This combined with more difficulty at birth will bring higher death loss in calves and more surviving calves will be poor doers," he said. "More cows, especially first time calvers, will not claim their calves."
Stenquist said that while these problems present serious economic repercussions to ranchers, the greatest hazard associated with thin cows is reproduction.
The thin cows, after calving, will go "all out" physiologically to adequately nurse their calves.
"In order for the cow not to self-destruct, nature has provided that such cows will not rebreed," he said. "They do not cycle, do not come in heat, while under this nutritional stress."
He said many thin cows, particularly heavy milkers, may not cycle until after the calf is weaned. "This, of course, is an economic disaster."
Bennett said ranchers should not assume reproductive problems can be avoided if a great flush of grass comes in spring following calving, or that if they supplement and increase feeds prior to and during calving.
"Research has shown that this is too late," he said. "Cows need to be brought up to the desired condition level at least 90 days before calving."
"Many feeds and feed combinations can be used to provide a suitable diet for thin cows," he said. "Adequacy and economy are the two things that need to be stressed. Your USU Extension livestock specialist can help you with this."
Vitamin A and phosphorus supplements may also be considered.