Glenn Selk Explores the Costs and Benefits of Early Summer Calf De-WormingMon, 30 Apr 2012 14:50:36 CDT
Does the cost of worming spring born calves outweigh its benefits? What about de-worming both cow and calf? Oklahoma State University Extension Animal Scientist Emeritus Glenn Selk puts a pencil to the problem in this week’s Cow/Calf Corner Newsletter and comes up with some answers.
For many years, the average value of a pound of added gain on feeder calves was considered to be 55 to 60 cents. In today’s marketplace that figure is no longer accurate. Last week at the Oklahoma City National Stockyards, the value (for steer calves) of each pound added between 450 pounds and 575 pounds was worth approximately $1.18. This is lower than the average sell price because of the price slide between lighter and heavier calves. Nonetheless, this much higher value of added gain means that management practices that may have been marginal in profitability in the past now have tremendous advantages. One such practice is the de-worming of spring born calves.
Five de-worming trials were conducted at the Eastern Research Station located near Haskell, Oklahoma during the 1990’s. Crossbred cows and their Charolais sired calves were sorted by sex of calf, calf age and cow age, then randomly allotted to one of four treatments: 1) non-de-wormed control, 2) de-worm calf only; 3) de-worm cow only; and 4) de-worm cow and calf. Two or three treatments were applied each year including one control group. Each treatment was applied two or three years. Cows and calves were individually identified and weighed in early June. Treated animals received label-recommended dosages of ivermectin pour-on. Pairs grazed in rotation seven bermudagrass pastures overseeded with clover at a stocking rate of 2 acres per cow-calf pair during the 144 to 181-day trials. Initial studies indicated that a low worm infection rate was present in the first two years. At that time fecal egg counts ranged from 0 to 28 eggs per 3 gram sample of feces. De-worming cows in late spring had no significant effect on cow summer weight gains up until calf weaning time. Treating cows but not their calves resulted in a small advantage in average daily calf weight gains (0.1 pound/day); while treated spring-born calves had significantly greater daily weight gains (0.14 pound/day) while nursing non-treated cows. In other words, just de-worming the calves resulted in a 21 pound weaning weight advantage over non-treated controls. Treated calves nursing treated cows had significantly greater average daily weight gains (0.17 pound/day) than the untreated calves nursing untreated cows. Over the approximate 150 day period this weight gain advantage would total about 25 pounds additional weaning weight to calves in this treatment group.
As previously stated, in this series of studies, de-worming spring-born nursing calves in early summer resulted in summer weight gains of 21 additional pounds. Twenty-one pounds valued at $1.18 each produces $24.78 more per calf and should pay for the de-wormer and the labor to apply it. De-worming both cow and calf resulted in an increased summer weight gain of 25 pounds versus non-treated controls (or 4 pounds more than when the calf alone was treated.) In these studies, reproductive performance was quite high for both treated and non-treated cows, and no difference was noted. Different results may occur in different climates and under different stocking rates.
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