There are varying opinions on if and when to feed hay to calves. Although there has been extensive research done on this topic, there still is no sure-fire solution as to what the correct answer is. In fact, whether you should offer hay or not depends on milk volume being fed, what kind of starter grain is offered, calf housing, weaning process, and of course, the nutritional quality of the hay. Extension educator Cassie Yost offered insight about how hay fits into a calf’s diet in a Penn State extension article.
Growing sufficient papillae is a direct result of a calf’s diet, and papillae development in a calf’s rumen sets it up for success. Papillae are formed by microbial fermentation from butyric and propionic acid and allows the calf to absorb nutrients that can later be utilized. “When hay is digested, the result is mainly acetic acid and some propionic acid. Unlike butyric, which is used by the rumen wall, acetic acid is passed through the rumen and utilized by the calf for energy,” Yost wrote. “Therefore, one of the leading arguments against feeding hay has been that the digestive benefits of grain far exceed that of hay, especially when focusing on rumen development.”
What’s in your starter plays a role in if hay should be offered. Calf starters can come in many forms, such as textured or pelleted. If your starter has a smaller particle size, starch will ferment faster in the rumen, which could lead to acidosis. Pelleted starters make starch more readily available because of the manufacturing process. Adding hay into this diet can help buffer the rumen and slow down digestion. “In textured starters, calves must chew the ingredients to break down the available starch. Calves eating texturized starter will be at lower risk for acidosis and can be on a nonforage diet for a longer period than calves fed a pelleted starter,” said the extension educator.
In a recent study, calves were offered the choice between a textured starter and chopped hay separately, or a mix of the two. Although there were no noticeable differences in intakes in the preweaning phase, during the postweaning phase, calves consuming the mixture of both had less dry matter intake and lower daily gains. The study concluded that the calves eating starter along with hay consumed more hay because their ration was a mixture rather than a choice, said Yost. This allowed for the calves to feel full quicker, resulting in less intake and gain. “Therefore, if hay is going to be included in the ration for calves, it is important to provide it separately from the calf starter, so calves are not limited in grain intake as their nutritional sources change,” she cited.
There are many benefits and deterrents of feeding hay to calves, and it can be a tough decision based upon varying research. The decision should focus on the farm and what works best for their operation, along with the calf’s diet, weaning, and housing situation.
