1998 ESA North Central Branch Meeting Abstract
73 THE ECONOMIC AFFECT OF HORN FLIES ON WEANING WEIGHTS OF SPRING BORN CALVES IN THE NEBRASKA SANDHILLS. John B. Campbell, and D. J. Boxler and D. C. Adams, University of Nebraska-West Central Research and Extension Center, Route 4 Box 46A, North Platte, NE 69101
Three groups of cattle; two treated with various insecticides impregnated in ear tags, and one group left untreated, were rotated through 3 pastures 3 times (9 years). On average each group consisted of about 42 cow-calf pairs. Cows were stratified across groups by age then randomly assigned to treatments. Calves were weighed when cows were placed on the summer pastures and again when they were weighed and moved to winter pastures. Horn fly numbers were recorded weekly from 15 randomly selected cows from each group weekly. Trial duration averaged 115 days and horn fly numbers on treated cattle averaged 72.48 versus 247.05 flies on untreated cattle, which averaged a 68% reduction. Overall, the average weaning weights for calves from treated cows averaged 11.04 pounds per calve more than calves from untreated cows. Weaning weights were significantly different five of the nine years, but were always greater from the treated cows. The economic advantage for treatment averaged $6.45 per calve using a $0.72 cent average value per pound for calves at weaning and a treatment cost of $1.50 per cow.
This paper will be presented on Monday.
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