Pat Hoffman can't recommend the single best forage for dairy heifers.
“For the most part, we feed lactating dairy cows alfalfa and corn silage, but with dairy heifers, we have 20 or more forage options that can work absolutely wonderful,” says Hoffman, a University of Wisconsin-Madison dairy scientist. “It's just a matter of selecting what works for a specific situation.”
Factors that influence forage selection include the heifer grower's harvesting equipment, crop rotation, soil type and nutrient management plan.
“Producers also need to understand the environment their heifers are housed in and what the energy requirement is for that environment and try to produce forages that fit,” says Hoffman. “Young, small heifers in cold-housing systems in winter have moderately high energy requirements. Big, bred heifers in well-bedded freestall barns have very low energy requirements.
“But one of the biggest challenges of feeding the modern dairy heifer is to have forage-production systems in place that don't result in overconditioning,” he adds.
The forage that creates the most problems is corn silage, he says.
“It has a lot of calories, and, depending on the heifers' environment and energy requirements, it doesn't take a lot of corn silage to cause overconditioning. If corn silage is going to be fed, another forage has to be available to cut its energy density.”
Here are forage options heifer growers might want to consider:
Crop residues, such as cornstalks and straw. “These can work very well because their low energy levels balance high-energy diets,” says Hoffman.
Small-grain silages. “When harvested at the head stage of growth, they make excellent heifer forage.”
Soybean residue. “This should be fed at a low inclusion rate because it has very low digestibility, but it can be used to a small extent to cut the energy content of corn silage.”
Sorghum-sudangrass. “It yields well and requires a lot of nitrogen, which can be a benefit to many ma-nure-management programs. But be-cause of its moderate energy content, it shouldn't be fed with corn silage.”
Tropical or earless corn silage. “It yields up to 6 tons of dry matter/acre and has a great set of nutritional advantages. But it's a challenge to grow in the northern Corn Belt because it's difficult to get seed and it needs to freeze to dry down.”
Legume-grass mixtures. “If cut at a later maturity, they're well-suited for dairy heifers and producers might be growing them anyway. Instead of taking four cuttings, they might want to consider taking only three,” says Hoffman.