Editor's note: The following article originally appeared in the October issue of the Miner Institute Farm Report, available here.
When thinking of calves and what it takes to grow them properly the main component of their diet is milk or milk replacer. However, it’s important to think about the other components of their diets as well. Milk is fed to calves for only a limited time, and the transition to a solid diet is relatively quick. To create a smoother weaning period and maintain growth post-weaning it’s important to encourage intake of more than just milk, even in the pre-weaning period.
The main question is besides milk, what should we be feeding calves to make them grow and transition the best? A concentrate is common throughout most calf programs, but is that all that’s needed? Should some sort of forage be offered? And if so, what kind of forage? There are a number of different views and opinions about this topic, but I’m hoping to shed some light on the advantages of offering forages to calves.
In general and across several different recent studies, in the preweaning period intake of pelleted starter feed does not differ between calves offered forage and those not offered forage. During this period, calves offered forages tend to prefer the forage to the concentrate. In instances where a forage and concentrate were offered as a mixed feed, calves learned sorting behavior at an early age and would sort the offered feed, consuming the forage in higher than expected amounts. Calves that learned this sorting behavior were more apt to continue to sort their rations after weaning compared to those calves offered concentrate and forage as separate components in different buckets.
Post weaning, the preference of the calves shifts to the concentrate over the forage. Perhaps this shift is to make up for nutrients that were previously provided by the milk. During the post weaning period calves with ad libitum access to both forages and concentrates have greater concentrate intake and total dry matter intake, resulting in higher average daily gains compared to calves strictly offered a concentrate.
This greater intake of concentrates is thought to be facilitated by an increase in rumen pH that occurs when forages are consumed, making a better rumen environment giving calves the ability to consume more grain. Calves offered forages also exhibited lower ruminal concentration of volatile fatty acids (VFA), despite the higher intake of concentrates, which may be due to these calves having a greater ability to absorb produced VFA.