We hear a lot about milk or milk replacer feeding for calves, but Pennsylvania State University’s Jud Heinrichs emphasized the importance of feeding calf starter in a recent presentation.
In a newborn calf, the abomasum is the largest stomach compartment, and that is where milk is digested. However, by 3 to 4 months of age, the rumen should be the main compartment.
“The number one thing you should be doing with that baby calf is growing a rumen because she is going to live on that the rest of her life,” Heinrichs said during the Professional Dairy Producers of Wisconsin (PDPW) Calf Care Connection workshop held earlier this month.
How can we encourage rumen growth?
“Grain intake is what does it,” he said.
Seeing is believing
Heinrichs showed attendees stomachs from three recently harvested calves. The calves were all the same age. One was on an all milk diet; one calf received milk and limited grain; and the third was fed a diet of milk, grain, and hay.
There were obvious differences between the three rumens.
The size of the rumen was much bigger in the calf that was consuming grain and hay. That rumen also had the most papillae, which are the finger like-projections that grow out of the inner layer of cells in the rumen and absorb nutrients.
“The week that we wean her until the day she exits the farm, she is relying on her rumen for all of her nutrients,” Heinrichs said. He explained that it takes 21 to 28 days to grow the rumen of a dairy calf once it starts eating starch.
He recommended feeding grain early on, about half a pound daily starting at 3 weeks of age. The calf should be consuming more than a pound of grain 14 to 21 days before weaning so that it has at least three weeks to grow the rumen.
“Grain intake before weaning dictates grain intake the week after weaning and the month after weaning,” Heinrichs explained. “The more grain we can get into the calf, the faster she will grow.” This will help the calf transition more successfully through the postweaning period.
His recommendation for milk or milk replacer feeding, which he said is based off of research, is to feed no less than 5 quarts but no more than 6 quarts per day. He would like the amount of milk to be reduced five to seven days before weaning to make sure calves are ramping up their starter intake.
As for forages, he said to introduce them once calves have a well-developed rumen. When they are eating 5 pounds of grain, day after day, they are at the point where their rumen is functioning, and Heinrichs said they will have a desire to balance their rumen pH and chew their cud.
Following these recommendations, he once again emphasized the importance of developing the rumen.
“This particular organ is what makes a dairy cow able to do what she can do,” Heinrichs shared. “There aren’t many other species that can produce more than their body weight in milk protein and fat every year. A cow can do it year after year after year.”