Records from the Tucumcari, NM Bull Test have been compared from 1961 to 2000. Over that time on-test weights increased from 550 lb to 717 lb, and off-test weights from 796 lb to 1135 lb. Birth weights increased 6.6 lb and weaning weights 121 lb. Some of that is due to more Charolais and Angus and less Herefords being tested. Regardless, we're dealing with a lot different population. No wonder carcass weights are so high.
PARASITES
Arkansas researchers grazed stocker calves from mid-summer to mid-fall on pastures previously grazed for two years by parasite-infected animals. Several parasite-control treatments were compared to untreated controls. Treated groups gained as much as 1.23 lb/day, compared to 0.53 lb/day for controls. Pastures had no cattle on them from mid November to early March. At that time, two parasite-free tracer calves were placed on each pasture, grazed for 30 days, and sacrificed. Internal parasite counts were almost 4 times higher in the tracer calves that had been on the pasture grazed the previous year by untreated calves
REPLACEMENT HEIFER PRICING
Yearly market fluctuations can make it hard to figure what to pay for replacements. A Wyoming producer has developed a formula he thinks might be fair over time to both buyer and seller. For bred, ready-to-calve two-year-olds he uses the October Feeder Cattle Futures price, plus $10/cwt. If the futures price is $80 the replacement heifer price would be $90, or $855 for a 950lb heifer. For coming second-calf three-year-olds, he uses the same formula, plus $150.
CARCASS TRAITS VS COW WEIGHT
The US Meat Animal Research Center studied mature cow weight and carcass factors across 23 widely varying breeds. Heritability of mature cow weight adjusted for body condition was 0.57, and ranged from 0.45 to 0.65 for most carcass traits. But tenderness heritability was only about 0.25, and for flavor and juiciness was essentially zero. Genetic correlations between cow weight and carcass traits were low. So it should be possible to genetically select for such things as marbling and cutability without affecting cow weight one way or the other.
TARGETS, BATTLES, AND WARS
The most common target you hear these days is 70-70-0, that is, 70% Choice, 70% Yield Grade 1 and 2, 0% outliers (weight, ribeye size, dark cutters, etc). The breedtype weapon to hit that target? 75% British - 25% Continental or 50-50, with no Brahman-type influence. Instead of targets, let's consider profit and call it a war. Then carcass merit is just one battle in the war. Other battles are reproduction, pounds, health, and cost. You can win a battle but lose a war. Depending on production conditions, it may take different genetic combinations to win this war.
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