Exposure to toxic fescue during late gestation on beef cows: effects on cow performance and offspring performance from birth to weaning

Abstract

To examine the effects of endophyte-infected tall fescue during late gestation on maternal and offspring performance, multiparous Angus cows (n = 40) were bred via AI and allocated into grazing treatments: toxic (E+) or nontoxic (E-) endophyte tall fescue. Cows body weight (BW), body temperature, body condition score (BCS), and respiration rate were recorded and blood samples collected on 180, 210 and 240 days of gestation. Calf's BW were recorded at birth and weaning. Cow/calf pairs were managed as one group on nontoxic pasture from calving until weaning (180 days of age). Body weight decreased (P = 0.022) and body temperature increased (P < 0.0001) at day 240 in E+ compared to E-cows. BCS did not differ (P = 0.891) between treatments. Respiratory frequency increased (P = 0.003) in E+ compared to E-cows. Ergovaline concentration of urine increased (P = 0.003) at day 210 and 240 in E+ compared to E-cows. Prolactin concentrations decreased (P < 0.0001) at day 210 in E+ compared to E-cows. Birth and weaning weight decreased (P < 0.05) in calves from E+ cows compared to E-cows. Overall, grazing endophyte-infected tall fescue reduced maternal and subsequent offspring BW.