By Francis L. Fluharty

Transitioning newly weaned calves from forage to grain and grain byproducts is a critical time in the feedlot. Since many feeders only receive calves once a year and fall weaning is just around the corner, here’s a quick reminder of things to consider.

Corn has twice the energy density and digestibility of most forages, so a pound of corn yields four times the amount of digestible energy as a pound of grass. Allowing animals an adequate time to adjust to corn, metabolically, is critical, as the bacteria in the rumen can digest the feed faster than the animal may be able to use this additional energy, resulting in a low rumen pH and acidosis.

Many animals are seeing an automatic waterer and learning to eat from a feed bunk for the first time. Further, take into account the fact that newly weaned animals in confinement are developing a new social hierarchy, are being exposed to several potentially harmful pathogens that must be managed through vaccinations and may develop respiratory problems if they are further stressed with rapid diet changes. A gradual increase in energy-dense feed intake is necessary. Having a controlled intake allows animals to adjust to grain-based diets and allows them to achieve ad libitum feed intake on a pen basis in a manner that minimizes the likelihood of acidosis and respiratory disease outbreaks.

Two critical pieces of information that are needed to create an effective receiving period protocol are the number of calves in the pen and their average initial weight. Reducing within pen calf size variability is important, as feed intake is based on the average weight. If there is more than a 25% variation in weight, large animals may overconsume feed resulting in acidosis, and the feed that is taken away from smaller animals may result in there being a negative energy balance, which sets them up for being susceptible to bacterial and viral respiratory diseases.

Slick bunk management should be used. When done appropriately, this does not reduce the intake of a group of cattle over time. To effectively use slick bunk management, care must be given to never increase the amount fed in any given day by more than 5% to 10% of the prior day’s intake, and cattle should never have an increase in total feed intake at the same time the corn portion of the diet is increasing. Additionally, the total diet should not contain more than 60% grain on a dry matter basis. Remember that half of corn silage is grain on a dry matter basis. Also, increase intake conservatively, and never increase feed intake two days in a row once a pen of cattle has achieved ad libitum intake. This should minimize digestive disorders.

Example for newly arrived calves
Each group of calves is different, and the percentage varies by the type of diet you feed.

Day                        Feed as % of body weight on dry matter basis

1                              1.50%

2                              1.60%

3                              1.70%

4                              1.80%

5                              1.90%

6                              2.00%

7                              2.05%

8                              2.10%

9                              2.15%

10                           2.20%

Rules for implementation
• Feed whole shelled or coarse ground corn (without a screen in the grinder). Young calves chew whole shelled corn so that it’s coarse-ground in the rumen.

• When any pen reaches the point where they are leaving a half-pound per head per day, that pen will be considered to have reached ad libitum intake and be held for at least one day before an increase in intake.

• If a pen is still consuming all feed offered at 2.2% of body weight, it will be held for two days before having its feed offering increased.

• Provide clean water and alfalfa or high-protein, grass-legume hay directly off the truck, and allow cattle a rest period before processing them.

• Make sure there is an electrolyte solution in the water that the calves drink immediately off the truck to restore cellular sodium and potassium levels.

• Provide 30 cm (12 inches) of bunk space per calf for the first 14 days.

• If corn silage is being fed, it must be kept fresh. Clean out feed bunks daily.

• Remember not to push feed to the back of the bunks where calves can't reach it. Don’t pull feed so far forward that calves can't see it when they look in the bunk. Keep feed about in the middle of the feed bunk.

• Pull feed to the center of the feed bunk every four to six hours for the first 48 hours. Do this slowly so the cattle are intrigued but not scared.

• Never walk in the feed bunks, as this spreads pathogens from your boots.

• Feed newly arrived cattle the same time each day.

Fluharty is a research professor in the Ohio State University Department of Animal Sciences, and a member of the OSU Extension Beef Team.