Iowa Beef Center Recommends Weaned Calf Nutrition

Feed selection. Often, calves are introduced to new feeds for the first time at weaning. "The calves and their rumen bacteria are accustomed to mothers’ milk and grass," Loy explained. "It takes one to two weeks for the rumen microbial population to adapt to new feedstuffs and the introduction of grain requires a major shift." Start out with feeds that the calves are accustomed to: Creep fed calves have the feeds used in the creep for at least for the first few days; additionally, calves are acclimated to grass; so long stem hay for the first three to seven days is a normal recommendation.

Calves usually prefer a dry grain mix at first, but will quickly adapt to high moisture feeds including corn silage over a one- to two-week period. In the past, Iowa State University researchers have successfully started calves on many different feedstuffs including corn gluten feed, soyhulls, corn silage, green chop, and haylage. In 10 years of starting trials at the ISU Rhodes Research Farm researchers learned:

• Corn gluten feed adds energy and protein without contributing starch.
• Soyhulls also add fiber, but not roughage.
• Big bales reduce performance, but cattle compensate if placed on a TMR.
• Whole corn/alfalfa is an acceptable starting ration
• Calves can be started on corn silage, but a two-week adaptation is best.

• Complete commercial pellets are a feasible alternative, but must be managed.

Monitor and Manage Feedbunks. Newly weaned calves should have enough feedbunk space so all the calves can eat at one time (18 to 24 inches per calf). Many different feeding systems are used to successfully start calves on feed. A total mixed ration is the easiest to control and monitor. This ration can be put together with a host of grains and roughages and can be fed in addition to the long stem hay for the first few days. Many feeders say slightly limiting intake and keeping calves somewhat aggressive allows for easier detection of sick calves.

One approach to managing feed intake is to feed 2 percent of the bodyweight as long stem hay on day one. Introduce about 1 percent of their body weight on a dry matter basis of the complete ration on the second day and begin phasing out the long hay. Increase calf intake about a pound of feed every two to three days. "Each group of calves is different, and health problems may cause some setbacks, but a normal healthy group of calves should consume 2.5 to 3 percent of their body weight by the third or fourth week on feed. The calves are then ready to be stepped up on grain if that is the system," Loy said.

Meet nutrient requirements. Complete starting rations or TMRs should be formulated to provide enough energy for sufficient growth, but enough forage to aid in the transition from forage to grain. For normally weaned, well-managed calves, a ration that is 50 to 60 percent concentrate and 47 to 50 Mcal/cwt. NEg is ideal.

Early-weaned, high-stress or high-risk calves need a 65 to 75 percent concentrate mix to ensure higher energy intake at lower feed consumption. Protein should be anywhere from 13 to 14.5 percent for early-weaned 300 to 500 lb. calves. Newly-weaned calves cannot utilize urea as effectively as older cattle, so a natural protein source or a supplement that includes a high bypass source with urea is preferred. Additional minerals including calcium, phosphorous and potassium may be required depending on the feedstuffs. Vitamins A, D and E should be part of the supplement. Trace minerals including zinc, copper and selenium may be needed in higher levels than the requirement to help fight disease. Table 1 illustrates general nutrient specifications for weaning rations.

Table 1. General Nutrient Specifications for Weaning Rations (dry matter basis)