90 Exposure to Endophyte-Infected Tall Fescue Negatively Impacts Pulmonary Arterial Pressure in Beef Cattle

Abstract Fescue toxicosis negatively impacts cattle productivity. Previous data from our laboratory has demonstrated that within a herd respond differently when grazing tall fescue, thus variation breed may provide genetic tolerance to the negative effects on performance. results in major cardiovascular system, it was hypothesized exposure ergot alkaloids pulmonary arterial pressure (PAP). The objective of this study examine changes PAP and other production parameters consuming endophyte-infected fescue. Pregnant Angus cows (2 4 years; n = 65) were randomly divided graze either (EI) or novel endophyte (EN) pastures for4 consecutive weeks starting April. Weekly measurements collected monitor physiological responses In addition, measured every weeks. Data analyzed using MIXED procedure SAS, statistical significance determined at P < 0.05 tendency 0.10, evaluated treatment, age, week, its interactions BW, ADG, BCS, HCS, HSS PAP. Exposure EI did not affect BCS (P >0.05). Whereas, hair coat scores (1-5 scale) significantly less for EN (2.15 ± 0.05) compared with (2.31 0.05; 0.05). Additionally, shedding reduced (2.3±0.05) (2.5±0.05; P< There significant difference exposed (37.16 0.59 mm Hg) (31.31 0.56 Hg; 0.0001). tended deviate over 14-week between treatment groups 0.0677). As expected, fescue resulted greater HCS HSS. However, decrease unexpected. Thus, further investigations are needed interaction alkaloid such as potentially predict differences beef identify animals would have lower risk developing toxicosis.