Combined effects of stocking rate and supplemental feeding level on adult beef cows grazing native rangeland in Texas.

Abstract

A grazing study was conducted over 4 yr to determine the effects of stocking rate and supplemental feeding levels on intake, and BW and body condition changes by adult beef cows. Stocking rates were 12.3, 16.5, and 24.7 animal units/(100 ha.yr). Supplemental feed treatments included a negative control (NC) and 300 g/(cow.d) of CP with either 2 (L), 4 (M), or 8 (H) Mcal/(cow.d) of DE from early December to late March. Groups fed supplements (L, M, and H) lost less BW from fall to spring (P < .01) and reciprocally gained less BW from spring to weaning (P < .01) than NC cows. The L cows tended (P = .14) to lose less BW between fall and spring than M and H cows. Treatment effects on condition score were similar to those for BW change. Forage intake, estimated by measurements of fecal output, was greater by supplemented cows (P = .02); L was greater than M and H (P = .004). Increased stocking rate correlated with increased fall-to-spring BW losses (P < .002), spring-to-weaning BW gains (P < .0001), and decreased winter forage intake (P < .005). These data provide quantitative bases for the effects of stocking rate and supplemental feeding on BW and condition dynamics. Low-level feeding of a high-protein supplement can increase intake of dormant range forage, thereby increasing nutrient intake. High-level feeding of low-protein supplements seems to increase nutrient status primarily by providing supplemental nutrients. Increasing stocking rate to the reported extremes decreased forage intake and resulted in unfavorable BW and condition changes.