To feed hay, or not to feed hay – that is the question.
The correct answer? “It depends,” according to Cassie Yost, Extension Dairy Specialist at Penn State University. Specifically, it depends on the calves’ age, stage of rumen development, how much milk is being fed, the physical form of the starter grain being fed, housing style, quality of the hay, weaning procedure and more.
All things considered, Yost detailed three research-based scenarios in which feeding hay to preweaned calves – and how to best do it – in a recent Penn State Dairy Extension bulletin. Her recommendations:
1. When pelleted starter is being fed – It has been proven that calves can do well – in terms of both consumption and gain – on either pelleted or texturized starter grain. But pelleting grain requires smaller feed particle size and thus faster starch fermentation in the rumen. This can lead to acidosis, which Yost said can be prevented by feeding accompanying hay to buffer the rumen and slow the digestion rate. “If calf starters consist of small particles, including too many fines because of sorting, hay should be included in the calf diet to prevent acidosis,” she advised.
2. In group housing situations – Yost cited research from the University of Florida in which groups of calves were raised on autofeeders and pelleted starter grain, with or without free-choice hay. The researchers chose low-quality, chopped grass hay to provide the sensory experience of eating hay without promoting excessive consumption that would create gut fill and limit starter intake. The study showed that the calves offered hay visited the autofeeders more frequently and consumed more, smaller meals, with fewer unrewarded trips to the autofeeders. The hay-fed calves also showed less pen-directed sucking during the weaning period.
3. As a side-dress, not a “TMR” – In a study conducted in Japan, preweaned calves were fed texturized starter with hay chopped into the solid ration, compared to those fed the same starter with hay offered separately. Both groups achieved equal average daily gain (ADG) and feed intake in the preweaning period, but by the time they were weaned, the calves on the mixed ration had a decrease in feed efficiency. During the post-weaning phase, that lag continued, with calves on the grain-hay mix consuming less dry matter with lower ADG. The researchers concluded that the calves on the mixed ration consumed more hay as they sought the grain in the ration, resulting in faster gut fill and thus lower total feed consumption and weight gain.
Yost concluded that hay can be part of an effective preweaned calf nutrition program, depending on a range of factors. Your herd nutritionist can help sort out the details regarding if and when feeding hay makes sense for your operation.
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