|Hubbell Iii, Donald|
|Rosenkrans, Jr., Charles|
Submitted to: Arkansas Agricultural Experiment Station Research Series
Publication Type: Experiment Station
Publication Acceptance Date: 8/15/2007
Publication Date: 12/15/2007
Citation: Coffey, K.P., Coblentz, W.K., Caldwell, J.D., West, C.P., Ogden, R.K., Hess, T., Hubbell III, D.S., Akins, M.S., Rosenkrans, Jr., C.F. 2007. Cow and calf performance while grazing tall fescue pastures with either wild-type toxic endophyte or a non-toxic novel endophyte. Arkansas Agricultural Experiment Station Research Series 553. Arkansas Animal Science Department Report 2007. 10:67-69. Interpretive Summary:
Technical Abstract: Fescue (Festuca arundinacea, Schreb.) pastures are common in Northwest Arkansas but cattle performance has declined due to the toxicity caused by the wild-type endophyte Neotyphodium coenophialum in the fescue plant (E+). Our objectives were to compare performance by spring-calving cows grazing E+ tall fescue with that by cows grazing a non-toxic endophyte-tall fescue association developed at the University of Arkansas (HM4). Gelbvieh x Angus crossbred cows (n = 134; 1,078 lb initial BW) were allocated randomly by weight and age to one of four 25-acre pastures in 2005 and one of eight 25-acre pastures in 2006. The pastures were allocated randomly such that half contained E+ and half contained HM4. Cows confirmed as pregnant began grazing the experimental pastures on October 15, 2004, and November 30, 2005. Cows remained on their assigned pastures until weaning in 2006, but were removed from HM4 in the summer of 2005 because of low forage availability from extremely dry summer conditions. Cow BW and pregnancy rate were greater (P < 0.05) and hair scores were lower (P < 0.05) at weaning from HM4 than E+ pastures, and cow BW at the end of the breeding season tended (P = 0.07) to be greater from HM4 than E+ pastures. Calf birth date and birth weight were not different (P > 0.48) between forages, but actual and adjusted weaning weight, and calf gain from birth to weaning were greater (P < 0.05) from HM4 compared with E+ pastures. Therefore, replacing toxic tall fescue pastures with non-toxic, novel endophyte-infected tall fescue may improve calf growth and cow reproductive performance.