Serum prolactin (PRL) and @entity251 concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic @entity18959 ( @entity18959 .  =  Schedonorous arundinaceum [Schreb.] Dumort.) cultivar Kentucky 31 (E+) compared with a novel endophyte cultivar lacking ergot alkaloids (E-) were evaluated. Angus bulls were allotted to treatment (Day 0) and grazed E+ or E- for 155  days. Treatment-by-day interaction was significant (P  <  0.05) for serum PRL concentrations with E+treated bulls exhibiting reduced PRL values compared with E- control bulls, but no differences were observed for serum @entity251 concentrations (P  >  0.05). Further, bulls on the E+ treatment exhibited @entity1017 , average daily gain, and body weight by Day 140 (P  <  0.05) compared with the E- bulls. Rump @entity121 was lower because the treatment in bulls grazing E+ compared with E- (P  <  0.05) and intramuscular fat in the E- bulls compared with the E+ group was higher by Day 155 (P  <  0.05). Analysis of ejaculates showed significant treatment * day effects for sperm concentration with lower values observed for bulls on the E+ treatment (P  <  0.05). The  percent normal morphology was reduced in ejaculates from E+ bulls compared with E-  bulls (P  <  0.05), and the difference was due to an increase in abnormal sperm present in the E+ ejaculates from Day 84 to 140 (P  <  0.05). In addition, spermatozoa motility and progressive motility were decreased on thawing in semen samples from E+ bulls compared with E- bulls (P  <  0.05).

Bulls grazing Kentucky 31 XXXX exhibit impaired growth, semen quality, and decreased semen freezing potential.

@entity18959 :: ('4606', 'Species') :: ['Lolium arundinaceum [Schreb.] Darbysh', 'tall fescue'] @entity251 :: ('MESH:D013739', 'Chemical') :: ['testosterone'] @entity1017 :: ('MESH:D015430', 'Disease') :: ['decreased total gain'] @entity121 :: ('MESH:D009135', 'Disease') :: ['muscle depth']
@entity18959 :: (4606,Species) :: ['tall fescue']
