If you've got mediocre hay on hand for your heifers, Mike Hutjens' advice is to sell it to local beef producers and replace it with higher-quality hay.
“Rained-on, late-cut forages have no place in growing-heifer rations,” says Hutjens, University of Illinois extension dairy nutritionist. “It'll slow them down two to three months. Too many heifers calve at 26 months of age vs. 23 or 24 months — when you ideally want them in the milking herd.”
Wayne Kellogg, University of Arkansas animal scientist, concurs.
“We've tended to overlook the importance of good-quality forages in dairy heifer rations,” says Kellogg. “The emphasis has been on feeding the very highest-quality forages to cows and that's appropriate. But cows milking later in their lactations don't need as much high-quality forage as heifers do.”
To gain weight at a sufficient rate, heifers need forages testing around 130 relative feed value (RFV) or higher, says Hutjens.
“Of course, many dairy producers harvest their own forages and it's impossible to get every field cut and harvested at the opportune time. However, with the prices of replacement heifers topping $2,000 each, it might be wise to buy some good-quality hay for them, if necessary.”
After calving, Holstein or Brown Swiss heifers should measure 54-56" tall at the withers and weigh around 1,250-1,300 lbs with a body condition score of 3 to 3¼, says Hutjens.
To meet those height and weight goals, heifers have to gain an average of 1.7-1.8 lbs/day. Growth varies with age, so gains may exceed 2 lbs/day in younger heifers and slow to 1 lb/day by the time they freshen.
“If heifers get most of their growing done before they calve, they perform better,” says Kellogg. “If you wait and make them grow after they're milking, you put a strain on them and cut their milk production that first year.”
For heifers less than six months old, Hutjens suggests feeding 4-6 lbs of grain plus a good-quality forage.
“Most heifers are going to need some grain up to six months of age to accelerate their growth,” he says. “Plus, their rumens don't have the capability to handle the amount of forages that older animals can.”
From six to 12 months of age, they'll start eating more forage. During that period, Hutjens recommends reducing the grain to 2-3 lbs/heifer/day and adding corn silage to their ration. Feed a 50-50 blend (dry matter basis) of corn silage and a legume or legume-grass mix.
Heifers over a year old will do nicely on the corn silage-legume balanced mix, plus a mineral-vitamin mix and an ionophore to improve feed efficiency, says Hutjens.
“Heifer rations need to run around 14% crude protein,” he points out. “So if the corn silage is coming in at 8% crude protein, then the legume has to be in 18-20% range to make it balance. But remember: You can't make a silk purse out of a sow's ear. If you've got 110-115 RFV hay, it can't be supplemented with enough good corn to get the job done.”
While Hutjens' recommendations work well for heifers in confinement, he knows many are raised on pasture.
“We've tended to overlook the importance of good-quality forages in dairy heifer rations.”
— Wayne Kellogg
“I have no problems with pasturing animals as long as producers carefully manage their pastures and complement their supply with other forages or feedstuffs to make sure heifers are growing enough.”
Management tips he recommends include clipping the pastures for weed control and rotating the heifers frequently to ensure a fresh forage supply.
In Arkansas and surrounding states, Kellogg has seen heifers thrive on well-managed pastures of cool-season grasses and small grains for fall and spring grazing, and warm-season grasses for summer grazing. Orchardgrass, bromegrass and sudangrass work well in pastures and provide good-quality forage, he says.
Kellogg recommends supplementing each heifer's pasture intake with about 3 lbs of corn grain, plus vitamins, minerals and protein.
“If I need more energy, I might feed wheat mids,” he says. “They add a little more energy and don't cost much.”