How much starter grain should preweaned calves eat? How soon should they start? What form of feed do they prefer?
Dale Moore, Clinical Professor and Director of Veterinary Extension at Washington State University, emphasized the three critical reasons starter grain consumption is important in preweaned calves: (1) rumen development; (2) immune system development; and (3) supporting early growth and weight gain, which is associated with earlier puberty, lower age at first calving, and better first-lactation milk production. In an exhaustive analysis of research, Moore explored a wide range of factors pertaining to starter grain consumption and relative calf performance.
While consumption rates at different ages varied significantly, Moore suggested calves should be consuming some grain by two weeks of age, and eating about one-half pound (about 1 cup) of starter grain by 4 weeks of age. Another rule of thumb is that calves should be consuming about 2 pounds (about 4 cups) of starter per day for three days in a row before they are weaned from the liquid ration.
Moore’s observations showed a wide range of factors that impact calves’ desire to consume starter, including:
-Different levels of liquid feeds – Calves that are “limit-fed” milk or milk replacer (in the range of 2 quarts, twice a day) should eat more starter grain to meet their nutritional needs for weight gain and growth. This can be challenging in cold-weather conditions. Moore cautioned that limit-fed calves 3 weeks of age or younger cannot be expected to consume enough starter grain in cold weather to make up for nutritional deficiencies, and need more liquid nutrients instead.
-Disease – Moore found several studies indicating calves experiencing diarrhea showed a setback in grain consumption. “It is vital for an individual calf with diarrhea to continue receiving its milk ration for maintenance requirements, because they will not be getting many nutrients from starter grain,” advised Moore.
-Water availability – Clean water provided daily encourages starter consumption. Calves deprived of water may consume about a third less starter grain, leading to about a 38% reduction in weight gain. Starter grain texture, formulation and freshness – Calves consume more starter grain in the textured, multi-particle form, but pelleted starters have been associated with higher feed efficiencies. Starch source also matters, as calves prefer corn-based starters versus oat- or barley-based formulations. Calves consume more starter grain if it is fresh and not dusty or moldy. Reducing water contamination by keeping grain and water separated is advised.
-Calf housing, weather and management – Calves housed in pairs have been shown to eat more starter grain than those housed individually, although this consumption difference has been found not to be significant until after 5 weeks of age. Both cold and heat stress can demand more nutrients for calves. Again, however, these needs should be compensated with liquid nutrients in calves 3 weeks of age or younger. Placement of the grain pail also is important. If it is too high (over 24” for Holstein calves) grain consumption will be impeded. Finally, calves provided extended lighting (18 hours per day) have been shown to consume about twice as much starter at 4 weeks of age compared to calves exposed to 10 hours of light per day.
Moore advised that initiating the level of rumen development needed for calves to transition to an all-grain ration takes about 3 weeks. Thus, it’s important to begin offering starter grain and fresh water at 3 days of age, even to calves fed higher levels of liquid nutrients. Getting the proper nutrients into the calves will set them up to meet your weaning, breeding and calving age goals.