Kerr L A, McCoy C P, Boyle C R, Essig H W
College of Veterinary Medicine, Mississippi State University, Mississippi State 39762.
Am J Vet Res. 1990 Jan;51(1):76-8.
A group of 48 crossbred steers (approx 250 kg each) were used to determine the effects of various diets and treatments on serum prolactin concentrations and rectal temperatures. The steers were randomly assigned to groups fed the following: (1) endophyte fungus-infested fescue hay; (2) ammoniated endophyte fungus-infested fescue hay; (3) endophyte fungus-infested fescue hay plus 1 g of thiabendazole (TBZ)/9.1 kg of body weight at 7-day intervals; (4) ammoniated endophyte fungus-infested fescue hay plus 1 g of TBZ/9.1 kg at 7-day intervals; (5) ground Bermuda grass hay; and (6) endophyte-fungus-free fescue hay. Blood samples for prolactin determinations and rectal temperatures were obtained biweekly beginning on week 3 and continuing through week 9. A significant correlation (P less than 0.05) between low prolactin concentrations and high rectal temperatures in cattle eating endophyte-infested fescue hay was determined; however, as the prolactin concentrations approached normal (control animal) concentrations, this relationship between serum prolactin and rectal temperatures was not observed. Two antifungal agents used in this experiment (thiabendazole and ammonia) appeared to have different effects on the variables measured. Thiabendazole had no significant effect on prolactin concentrations or rectal temperatures of cattle ingesting endophyte-infested fescue hay, whereas ammoniation of this hay induced significantly higher (P less than 0.05) prolactin concentrations and lower rectal temperatures than in steers receiving only endophyte-infested fescue hay. Therefore, ammonia may be valuable not only as an aid in determining the cause of the fescue problem but also as a practical solution to some of the fescue-related economic problems in the cattle industry. Also, prolactin concentrations may be valuable in diagnosing fescue-related problems.
选用一组48头杂交阉牛（每头约250千克）来确定不同日粮和处理对血清催乳素浓度及直肠温度的影响。这些阉牛被随机分为以下几组进行饲养：(1) 感染内生真菌的羊茅干草；(2) 氨化处理的感染内生真菌的羊茅干草；(3) 感染内生真菌的羊茅干草加每9.1千克体重1克噻苯达唑（TBZ），每隔7天投喂一次；(4) 氨化处理的感染内生真菌的羊茅干草加每9.1千克体重1克TBZ，每隔7天投喂一次；(5) 百慕大草碎干草；(6) 无内生真菌的羊茅干草。从第3周开始，每两周采集一次用于测定催乳素的血样和直肠温度，持续至第9周。结果发现，采食感染内生真菌羊茅干草的牛，其低催乳素浓度与高直肠温度之间存在显著相关性（P小于0.05）；然而，当催乳素浓度接近正常（对照动物）浓度时，未观察到血清催乳素与直肠温度之间的这种关系。本实验中使用的两种抗真菌剂（噻苯达唑和氨）对所测变量似乎有不同影响。噻苯达唑对采食感染内生真菌羊茅干草的牛的催乳素浓度或直肠温度无显著影响，而该干草经氨化处理后，与仅采食感染内生真菌羊茅干草的阉牛相比，催乳素浓度显著升高（P小于0.05），直肠温度降低。因此，氨不仅可能有助于确定羊茅问题的成因，而且可能是解决养牛业中一些与羊茅相关经济问题的切实可行办法。此外，催乳素浓度在诊断与羊茅相关的问题时可能具有重要价值。
