Monensin supplementation for increased productivity in stocker cattle on California grazeland

Principal Investigator: Gabriele Meier

The usefulness of ionophore supplementation in stocker calves under typical conditions on California Mediterranean grasslands have been lacking until recently.

A recent study showed improved weight gain in stocker cattle on California rangeland that received a small dose of ionophore supplementation (50 mg/head/day) over those that did not [Forero and Davy]. Since this dose is considered small, much more economical gains seem possible with increased doses. However, given the variability of studies in other areas, informed recommendations from research conducted in California grasslands is required. Other sources have seen increased gains with rates up to 200 mg/d in other areas of the US [9].

This trial will be the first to test higher doses in California.

The goals of this study are to compare average daily gain in stocker cattle grazing California annual rangeland for different doses of monensin supplementation (0, 50, 125, 200 mg daily) while controlling for mineral status, starting weight, breed, and pasture quality.