title: Bulls grazing Kentucky 31 tall fescue exhibit impaired growth, semen quality, and decreased semen freezing potential.
abstract: Serum prolactin (PRL) and testosterone concentrations, body weight, body composition, semen quality, and semen freezing potential for bulls grazing the toxic tall fescue (Lolium arundinaceum [Schreb.] Darbysh. = 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 testosterone concentrations (P > 0.05). Further, bulls on the E+ treatment exhibited decreased total gain, average daily gain, and body weight by Day 140 (P < 0.05) compared with the E- bulls. Rump muscle depth 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).
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA. Electronic address: scottp@clemson.edu.
authors.forename: S L
authors.initials: SL
authors.lastname: Pratt
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Stowe
authors.affiliation: Large Animal Clinical Sciences, College of Veterinary Medicine, The University of Tennessee, Knoxville, Tennessee, USA.
authors.forename: B K
authors.initials: BK
authors.lastname: Whitlock
authors.affiliation: Department of Animal Science, University of Tennessee, Knoxville, Tennessee, USA.
authors.forename: L
authors.initials: L
authors.lastname: Strickland
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Calcatera
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Dimmick
authors.affiliation: USDA-ARS-Forage-Animal Production Research Unit, University of Kentucky Campus, Lexington, Kentucky, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Aiken
authors.affiliation: Department of Animal Science, University of Tennessee, Knoxville, Tennessee, USA.
authors.forename: F N
authors.initials: FN
authors.lastname: Schrick
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: N M
authors.initials: NM
authors.lastname: Long
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: S K
authors.initials: SK
authors.lastname: Duckett
authors.affiliation: Department of Animal and Veterinary Sciences, Clemson University, Clemson, South Carolina, USA.
authors.forename: J G
authors.initials: JG
authors.lastname: Andrae
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D015925:Cryopreservation / Q000662:veterinary; D004876:Ergot Alkaloids / Q000378:metabolism; D005247:Feeding Behavior; D008129:Lolium / Q000633:toxicity*; D008297:Male; D009929:Organ Size; D011388:Prolactin / Q000097:blood; D012611:Scrotum / Q000033:anatomy & histology; D055101:Semen Analysis / Q000662:veterinary*; D013739:Testosterone / Q000097:blood
chemical_list: D004876:Ergot Alkaloids; D013739:Testosterone; D011388:Prolactin
keywords: Breeding soundness examination; Computerized sperm-quality analysis; Fescue toxicosis; Scrotal circumference; Semen freezing