Potassium Level and Wintering Cow Performance: Study Two

Abstract

Ninety-six crossbred gestating cows were randomly assigned to one of three treatments that provided the following levels of supplemental K: 1) 7, 2) 47, and 3) 78g/h/d, respectively, in a cottonseed meal (CSM)-based range cube. Treatments 2 and 3 included potassium chloride as the source of additional K. A CSM-based range cube was fed to provide .18kg crude protein/h/d. Cows were gathered from the same dormant winter pasture three times per week, individually stalled, and fed their respective supplements.During the 93- to 96-d gestation period, cows fed supplemental K (treatments 2 and 3) tended to lose less weight than those not supplemented with potassium chloride. Supplementing K during the 23-d lactation period at the 94g/h/d K level tended to reduce weight loss compared to the control or 156gK level. Condition score change through calving was significantly improved with potassium chloride supplementation. Calf daily gain from birth to mid-April tended to be improved when cows were supplemented with 94gK. The K requirement for dry gestating beef cows appears to be approximately .65% on a dietary dry matter basis.