The Pros and Cons of Feeding Hay Early
January 7, 2021
Feeding hay to preweaned dairy calves remains a topic of frequent confusion and debate. Should you do it at all? And if so, when, and what type?
Penn State Dairy Extension educators Coleen Jones and Jud Heinrichs weigh in on the subject in their highly comprehensive primer on “Feeding the Newborn Calf.” For starters, they say research has clearly disputed the long-held belief that preweaned calves need hay to provide “scratch” to launch rumen development.
But they note there are other reasons why it may be helpful, as well as plenty of reasons to delay it.
Calves fed pelleted starter formulations may benefit from the buffering effect of forage. Some pelleted starters have high levels of readily fermentable starch, which can cause ruminal acidosis, especially when calves eat large quantities of 2 or more pounds of starter per day.
Forage feeding can provide physical abrasiveness that prevents keratin build-up on rumen papillae. This makes the rumen more functional and capable of greater nutrient absorption. However, the same effect can be achieved by feeding texturized starter grain, with greater consistency and density of nutrients.
Forage feeding is not necessary for calves fed texturized starter grain. This starter formulation puts calves at lower risk for acidosis because the starch in whole or partially processed grains is not as readily available, and thus will not ferment as quickly in the rumen.
Early feeding of hay (in calves as young as Day 1 of life) can discourage calves from consuming starter, and thus lower their energy intake.
Calves have limited space in their digestive tracts. Bulky forages fill this capacity quickly, suppressing appetites and again limiting energy intake.
Forage breaks down in the rumen into the amino acid acetate, which does nothing for rumen development. Grains, on the other hand, are fermented into butyrate and propionate, both of which play important roles in rumen development.
Variability in feed consumption can lead to uneven weaning groups. Some calves prefer forage over grain, and vice-versa, leading to inconsistent growth patterns among similarly aged animals.
Heinrichs and Jones suggest holding off on hay feeding until calves are consuming 5 to 6 pounds of texturized starter grain per day, at around 7 to 8 weeks of age. If the starter grain is in pelleted form with high amounts of ruminally digestible forage, hay should be introduced a bit earlier, at 5 to 6 weeks of age.
In either case, forage need not be high-quality. In fact, average-quality forage is recommended, so calves don’t choose forage over grain, which would reduce their energy intake.