Effect of Grazing Management on Cattle Diets and Nutrition in the Coastal Prairie

Abstract

Cattle diets and nutrition were studied using fecal analysis and bite counts under (1) continuous, yearlong (CG), (2)4·pasture, deferred-rotation (4PDR), and (3) highintensity, low-frequency (HILF) grazing treatments at the Welder Wildlife Foundation Refuge. Of 156 plant species consumed, only 23 provided greater than 1% each of the diet. Grasses comprised 95% of the diet, forbs 4%, and browse 1%. Four warm-season grasses, silver bluestem (Bothriochloa saccharoides), longtom (Paspalum lividum), vine mesquite (Panicum obtusum), and meadow dropseed (Sporobolus asper), comprised a large percentage of the diet in all 3 treatments. Texas winter grass (Stipa leucotricha) was the most highly-preferred cool-season grass. Plant community, soil type, season, and rainfall had greater effects on species consumed than did grazing treatment. On HILF the diet changed from highlypreferred to less-preferred species as the grazing period progressed. The 5 most highly-preferred grasses provided adequate crude protein and calcium to meet the minimum requirements of lactating cows except during winter. All 5 were deficient in phosphorus except during spring green-up. There were no differences in forage digestibility between treatments. Forage digestibility in HILF diets showed a significant (P < .05) decline after the first week of a 3-week grazing period.