title: The effect of gossypol in cottonseed meal on performance and on hematological and semen traits in postpubertal Brahman bulls.
abstract: The effects of a cottonseed meal diet containing high levels of free gossypol on hematological traits, including erythrocyte osmotic fragility and semen characteristics, were examined during an 11-week period. Eight Brahman bulls were randomly assigned to 1 of 2 groups. The control group (n=4) was fed a mixture of soybean meal and corn. The treated group (n=4) was fed a mixture of cottonseed meal and corn. Both groups were allowed hay free choice. The treated group consumed 8.2 g of free gossypol per bull per day. The percentage of normal spermatozoa was lower (P<0.01) in the treated than in the control group from Week 5 (49+/-9.8 vs 83+/-3.2%), which was primarily influenced by changes in mid piece morphology in the treated bulls. Erythrocyte osmotic fragility was higher (P<0.001) in the treated than in the control group over the entire study period, although group values diverged more acutely from Week 7 of treatment. Sperm motility was lower (P=0.04) in treated bulls than in control bulls at Week 9 (52+/-9.8 vs 82+/-6.2%). These data suggest that concurrent discernable changes in bull erythrocyte osmotic fragility and in semen characteristics can occur following commencement of a diet containing 8.2g of free gossypol per day.
authors.affiliation: Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, FL 32610, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Risco
authors.forename: P J
authors.initials: PJ
authors.lastname: Chenoweth
authors.forename: R E
authors.initials: RE
authors.lastname: Larsen
authors.forename: J
authors.initials: J
authors.lastname: Velez
authors.forename: N
authors.initials: N
authors.lastname: Shaw
authors.forename: T
authors.initials: T
authors.lastname: Tran
authors.forename: C C
authors.initials: CC
authors.lastname: Chase