Cow’s diet critical to calf performance

Dick Fredrickson, veterinarian at Simplot ranches and feedlots of Grandview, Idaho, says protein deficiency in cows is an important factor in whether their calves do well. If cows don’t have adequate protein, they can’t produce adequate colostrum. “This is the key to a healthy calf, assuming cows have adequate forage,” he says.

Good-quality colostrum is crucial to the newborn calf, to provide energy to keep warm, and antibodies to protect against disease. “Inadequate passive immunity from colostrum increases risk for sickness and death in calves, and decreases average gain in the nursing calf. This follows on through into the feedlot, with higher risk of sickness, respiratory disease and death, and a decrease in average daily gain,” says Fredrickson. Deprived calves never got their immune system off to a good start and never quite make up for it during their growing period, he says.

“In a study of 2-year-old pregnant heifers, one group received an adequate amount of protein, and another group received a restricted protein diet. They milked the heifers after they calved to evaluate colostrum. The heifers that received adequate protein had 2.75 quarts of colostrum, while heifers with low protein intake had 2.02 quarts,” he says.

“University of Nebraska did research on quality grade for steers whose mothers were supplemented. They looked at cows on cornstalks that were supplemented with protein versus cows that were not. Calves from dams that received protein supplementation graded 86% Choice. Those from dams that had no protein supplement graded 64% Choice,” he says. Protein also enables cows to use lower-quality forage.

Key Points

• Cows can eat low-quality forage for energy, if they have enough protein.

• Protein levels in cow diets affect survivability of their calves.

• Add protein to diet with alfalfa hay, or a high-protein “cake” or pellets.

Basic nutrition for pregnant cow

“In actuality you are not feeding the cow; you are feeding the rumen microbes so she can adequately digest forage. We have to feed the microbes that digest lower-quality forage,” says Fredrickson. “The microbes utilize minerals and protein to make enzymes that help them break down and digest forages. Microbes and enzymes then pass out of the rumen and are digested and absorbed in the intestines,” providing additional protein.

There are many ways to add protein to the cow’s diet, including a small amount of alfalfa hay, or a high-protein “cake” or pellet, or some other commercial protein supplement. High-starch supplements, such as corn and barley, don’t work because they interfere with fiber digestion. “Rumen microbes that digest starches don’t do a very good job of digesting roughages, and vice versa. The rumen flora multiplies to digest roughages, or starches, and are not in balance for the other,” he says. Alfalfa hay is an excellent protein source for cows on a forage diet. Beef cows should consume 2.5% of their body weight in good forage. Low-quality forages with low protein levels — straw, dry mature grass, cornstalks — will reduce digestive efficiency by as much as 30%.

Smith Thomas writes from Salmon, Idaho.

This article published in the March, 2010 edition of WESTERN FARMER-STOCKMAN.

All rights reserved. Copyright Farm Progress Cos. 2010.