Grass-fed beef producers need to provide ample amounts of high-quality pasture in a long grazing season, and the cattle still likely won’t perform as well as feedlot-finished animals.
That was the case at Iowa State University, where researchers wanted to find out if grass finishing would result in high-value carcasses if cattle with high marbling genetics grazed well-managed pastures.
Starting May 7 last year, 10 Angus heifers chosen for high marbling potential grazed a high-quality alfalfa-bromegrass pasture. Twelve were placed in a feedlot and finished on a grain-based ration. That diet consisted of 45% corn grain, 32% modified distillers grain, 20% ground hay and a supplement that included monensin. No cattle were implanted or fed hormones or antibiotics.
The grass-fed cattle initially were moved to a fresh paddock every three or four days, and excess forage was harvested to maintain pasture quality. In mid-July, they were given access to the entire 26-acre pasture due to dry conditions. On pasture until Nov. 1, they grazed stockpiled forage the last few weeks.
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The animals were given shade near the water source, flies were controlled with an insecticide dust bag, and bloat-preventive blocks were offered free choice.
The grain-fed cattle gained 3.44 lbs/day, reaching the 1,000-lb target market weight in 111 days. Gaining 1.98 lbs/day, the grass-fed cattle reached market weight in 177 days. Their carcasses graded 60% Choice compared to 90% Choice for the grain-fed cattle. The fat in the grass-fed carcasses was yellow, which can cause lower grades, say the researchers.
“Consistently producing a high-value carcass from forage-fed cattle is challenging,” they wrote.
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