Calf Starter Intake Drives Rumen Development
The primary factor determining ruminal development is dry feed intake. To promote early rumen development and allow early weaning, the key factor is early consumption of a diet to promote growth of the ruminal epithelium and ruminal motility. Because grains provide nonstructural carbohydrates that are fermented to propionate and butyrate, they are a good choice to ensure early rumen development. On the other hand, the structural carbohydrates in forages tend to be fermented to a greater extent to acetate, which is less stimulatory to ruminal development.
Many feed manufacturers use steam-flaked corn, which is considered highly digestible and palatable to young calves. Many consider it the “gold standard” for calf starters and an indication of a high quality product. Others use rolled corn, which is less expensive than steam-flaked. There has been a lot of interest to know which type of corn is optimal to promote early and aggressive intake and to allow the calf to be weaned at an early age. Which method of processing is best for calves? Which promotes intake and rumen development? In the October 2004 issue of the Journal of Dairy Science, Lesmeister and Heinrichs reported on a study where four different methods of corn processing were compared in calf starters.
The results, as can be seen in table 1, calves fed whole and dry rolled corn grew faster during the last two weeks of the study (wk 5-6). This increased growth was due to greater starter intake. Calves fed roasted or steam-flaked corn generally ate less starter during the last two weeks and therefore grew slower. Feed efficiency of calves fed whole or dry rolled corn were also greater compared to other calves.
Calves are good feed processors, they chew their feed well. The grain processing method does not influence calf performance. In addition calves fed whole corn had significantly higher rumen pH, a benefit of starch from whole shell corn being available for metabolism over a longer period of time and less acidotic to the calves.