Putting replacement heifers on pasture two seasons before they join a milking herd can save a producer up to $450/head in feed costs, says Dave Combs, University of Wisconsin (UW) dairy scientist.
The practice is “an opportunity to substantially reduce costs,” he said at a recent World Dairy Expo talk.
It also increases milk production, according to research from the UW Center for Integrated Agricultural Systems. Pasture-raised first-lactation cows yearly averaged 25,328 lbs milk compared with confinement-raised cows’ 23,415-lb average. Contributing to that production gain: Pasture-raised animals were better exercised with better body conditioning and exhibited less stress, since they were used to being handled.
Another benefit to being pasture-raised: Those heifers showed a higher average daily gain (ADG) – 1.97 lbs – compared to confinement-raised animals’ 1.86 lbs. The gain difference was minimal, said Combs, but shows that pasture-raised heifers can achieve rates of gain recommended for high-quality replacements.
Jerold Berg, Cascade, WI, has pastured replacement heifers for a neighboring 500-cow dairy for three years and said it works well. Maintaining a stocking rate that matches pasture conditions is the key to success, he said. The dairy is “willing to bring and take animals as I need as the pasture progresses.”
In early May, Berg starts grazing 40 pregnant heifers – knowing he can stock up to 90 during summer based on pasture conditions. Heifers move daily to two- to eight-acre paddocks of brome, orchard, canary, timothy and fescue grasses along with red and white clovers and alfalfa.
For grass-only pastures, Combs advises a grass blend that’s winterhardy and disease-resistant, particularly to rust, and has a good seasonal distribution of yield. Varieties within a grass species can show “significant variability,” so producers should compare university variety trial data before choosing.
Heifers need quality forage to maintain ADGs, and following milking cows in paddocks won’t provide it, Combs said. He said three nitrogen applications over the growing season will keep pastures lush.
Maintaining high-quality pastures will also reduce feed-supplement needs. On pasture testing at 45-50% NDF, 175-lb heifers need up to 5 lbs of grain or silage. Heifers weighing 575 lbs need about 1 lb of supplement. Typically, no extra feed is needed after breeding. If a pasture averages 62% NDF, heifers of either weight need more than a 6-lb/day supplement; once they are bred, it should increase to about 8 lbs.
Berg closely monitors the ratio of animals on acreage. Assuming 5 tons/acre dry matter on good pasture in favorable weather, he ensures each animal is consuming at least 3% of its body weight daily in forage. His pastured heifers’ ADG is 2 lbs. Other than a mineral blend, they receive no grain or additional forage supplementation.
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