Farm Talk

June 18, 2013

Early summer deworming affects summer weight gain

Keith Martin

Parsons, Kansas — A five year deworming trial was conducted at the Eastern Oklahoma Research Station located at Haskell, Oklahoma. In this trial crossbred cows and their calves were randomly allotted to four treatments: 1) non-dewormed control, 2) deworm calf only; 3) deworm cow only; and 4) deworm cow and calf.

Cows and calves were individually identified and weighed in early June. At that time, treated animals received label-recommended dosages of an ivermectin pour-on. Pairs grazed in rotation seven bermudagrass pastures overseeded with clover at a stocking rate of two 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 years. At that time, fecal egg counts ranged from 0 to 28 eggs per 3 gram sample of feces.

Deworming 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 calf weight gains. The cows (treated or un-treated) all remained in excellent body condition and had very high re-breeding rates.

Treated spring-born calves had significantly greater daily weight gains (0.14 pound/day) even though they were nursing non-treated cows. In other words, just deworming the calves resulted in a 21 pound weaning weight advantage over non-treated controls. If you value the additional gain at a conservative $1.00 per pound, the additional weaning weight will more than pay for the dewormer.

Treated calves nursing treated cows had significantly greater average daily eight 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. In other words, treating the cow in addition to the calf realized only another four pounds of weaning weight.

In this study, deworming spring born nursing calves in early summer resulted in

significantly greater summer weight gains. Producers with cattle in drier climates, on native range, and with lower density stocking rates may find different results. For more information about deworming or other cattle management practices contact Wildcat Extension District, Livestock Agent Keith Martin at (620)784-5337 or you can email me at rkmartin@ksu. edu. £