Samford-Grigsby M D, Larson B T, Forcherio J C, Lucas D M, Paterson J A, Kerley M S
Department of Animal Sciences, University of Missouri, Columbia 65211, USA.
J Anim Sci. 1997 Apr;75(4):1026-31. doi: 10.2527/1997.7541026x.
Two experiments were conducted to determine whether administering a dopamine antagonist to steers fed endophyte-infected (E+) tall fescue would increase serum prolactin (PRL) and reduce rectal temperature. Steers in both experiments were housed in environmentally controlled chambers (32 degrees C; 50% relative humidity). In Exp. 1, 10 steers were allotted randomly to receive s.c. injections of either 0, .006, .03, or .06 mg of Ro 24-0409 (dopamine antagonist)/kg BW. The experiment was designed in four phases: endophyte-free seed (E-) without antagonist (d -11 to 0); E- with antagonist (d 0 to 7); E+ with antagonist (d 7 to 28); E+ without antagonist (d 28 to 38). In Exp. 2, 22 Holstein steers were allotted randomly to the same treatments and design, except three steers were maintained on E- without antagonist. Steers were fed individually with intakes measured daily. In Exp. 1, feed intake and rectal temperature were not improved (P > .05) by antagonist injection. In Exp. 2, antagonist injections increased (P < .05) PRL. Ingestion of E+ decreased (P < .05) feed intake and serum PRL. Antagonist injection decreased (P < .05) rectal temperature and increased (P < .05) serum PRL.
进行了两项实验，以确定给食用内生真菌感染（E+）的高羊茅的阉牛注射多巴胺拮抗剂是否会增加血清催乳素（PRL）并降低直肠温度。两项实验中的阉牛均饲养在环境可控的牛舍中（32摄氏度；相对湿度50%）。在实验1中，10头阉牛被随机分配，皮下注射0、0.006、0.03或0.06毫克Ro 24 - 0409（多巴胺拮抗剂）/千克体重。实验设计为四个阶段：无内生真菌种子（E-）且无拮抗剂（第 -11天至0天）；E-且有拮抗剂（第0天至7天）；E+且有拮抗剂（第7天至28天）；E+且无拮抗剂（第28天至38天）。在实验2中，22头荷斯坦阉牛被随机分配至相同处理和设计，除了三头阉牛维持在无拮抗剂的E-组。阉牛单独饲养，每天测量采食量。在实验1中，注射拮抗剂对采食量和直肠温度没有改善作用（P > 0.05）。在实验2中，注射拮抗剂使PRL增加（P < 0.05）。食用E+降低了（P < 0.05）采食量和血清PRL。注射拮抗剂降低了（P < 0.05）直肠温度并增加了（P < 0.05）血清PRL。
