Using Orchardgrass and Endophyte‐Free Fescue Versus Endophyte‐Infected Fescue Overseeded on Bermudagrass for Cow Herds: II. Four‐Year Summary of Cow‐Calf Performance

A 4‐yr trial was initiated in January 2000 to evaluate cow‐calf performance on mixed‐species pasture systems consisting of (i) endophyte‐infected tall fescue (E+; Festuca arundinacea Schreb.) diluted by approximately 50% with common bermudagrass [ Cynodon dactylon (L.) Pers.] and other forages; (ii) endophyte‐free tall fescue (E−) overseeded into dormant common bermudagrass; and (iii) orchardgrass (OG; Dactylis glomerata L.) established under the same conditions as E−. The E− and OG pastures were grazed with either twice weekly (2W) or twice monthly (2M) rotation schedules, while pastures with E+ were grazed with 2M only. Actual weaning weights tended to be greater ( P = 0.096), and age‐adjusted 205‐d weaning weights and average daily gain from birth to weaning were greater ( P ≤ 0.035) for calves raised on low‐toxicity (E− or OG) pastures compared to those raised on E+. Over 4 yr, calves raised on low‐toxicity pastures exhibited 22‐ and 24‐kg advantages in actual and 205‐d adjusted weaning weights, respectively, compared to those raised on E+. Cows grazing OG and E− pastures exhibited greater ( P ≤ 0.021) body weights and body condition scores (BCS) at calving than cows grazing E+ pastures. Furthermore, reductions in body weight and BCS between calving and weaning tended to be greater ( P ≤ 0.088) for cows grazing E+ pastures. Calf performance was improved consistently by these low‐toxicity pasture systems, but management requirements may limit adaptation by producers.