Pre-calving treatment of cows with IVOMEC resulted in better body weight gains in calves, from birth through weaning

The benefit of cow treatment with IVOMEC on calf productivity was shown in a study involving 1,064 purebred or crossbred beef cows and heifers on eight ranches in western Canada.
Pregnant cows or heifers were matched by weight and allocated between two treatment groups:

• Group 1 was the organophosphate-treated Control
• Group 2 received autumn treatment with IVOMEC 1% Injection or IVOMEC Pour-On

Treatments were administered to the animals in late October to late November. Calving occurred in the spring. Calves did not receive any antiparasitic treatment prior to weaning.
Typical for the region, parasite challenge and fecal egg counts were low in cows and calves.
There was no clinical sign of parasitism, internal or external, in any of the cows or calves on trial. To assess the importance of cow treatment with IVOMEC on calf performance, calf body weights were adjusted to ensure that age and sex ratio did not affect trial results.

Despite the low challenge, cow treatment with IVOMEC resulted in a significant improvement in body weight gains in calves (P<0.05). The fact that this occurred in calves prior to going to pasture suggests that this benefit may have resulted from better milk production in the cow. The improved performance in calves from cows treated with IVOMEC was maintained through the end of the study, at the time the calves were weaned.

Data on file.

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