Stamm M M, DelCurto T, Horney M R, Brandyberry S D, Barton R K
Eastern Oregon Agricultural Research Center, Oregon State University, Burns 97720.
J Anim Sci. 1994 Apr;72(4):1068-75. doi: 10.2527/1994.7241068x.
Two experiments were conducted to evaluate digestion, performance, and physiological responses to Acremonium coenophialum-infected tall fescue straw offered to vary ergovaline concentrations. In Exp. 1, 16 Hereford x Angus ruminally cannulated steers (370 +/- 12 kg BW, mean +/- SE) were blocked by age and BW and, within block, randomly assigned to one of four treatments containing graded concentrations of ergovaline in the diet: 1) 0 ppb, 2) 158 ppb, 3) 317 ppb, and 4) 475 ppb. Alkaloid concentrations were produced using various mixtures of two varieties of tall fescue straw that had similar genetic and phenotypic characteristics but differed in degree of endophyte incidence and associated concentrations of alkaloids. In the 36-d digestion study, feed intake, apparent DMD, and total tract NDF digestion were not influenced by alkaloid concentration (P > .10). Differences were observed with digesta kinetics; specifically indigestible ADF (IADF) fill and outflow decreased linearly with increasing alkaloid concentration (P < .10). These differences, however, may be attributed to differences in IADF concentration of the diets. Physiological variables (heart rates, respiration rates, and rectal, ear, and tailhead skin surface temperatures) were not influenced by alkaloid concentration (P > .10). Concentration of serum prolactin measured weekly tended (P < .10) to decrease with increasing alkaloid concentration of the diet. At the conclusion of the study, each steer was injected with 100 micrograms of thyrotropin-releasing hormone (TRH). All steers responded to the TRH challenge (P < .10); however, responses did not differ (P > .10) between alkaloid concentrations of the basal diet (P > .10).(ABSTRACT TRUNCATED AT 250 WORDS)
进行了两项试验，以评估给不同麦角缬氨酸浓度的感染内生真菌的高羊茅秸秆时的消化情况、生产性能和生理反应。在试验1中，16头安装有瘤胃瘘管的赫里福德×安格斯阉牛（体重370±12千克，平均值±标准误）按年龄和体重进行分组，在组内随机分配到四种日粮处理之一，日粮中麦角缬氨酸浓度呈梯度变化：1）0 ppb，2）158 ppb，3）317 ppb，4）475 ppb。使用两种具有相似遗传和表型特征但内生真菌感染程度和生物碱相关浓度不同的高羊茅秸秆的各种混合物来产生生物碱浓度。在为期36天的消化试验中，采食量、表观干物质消化率和全肠道中性洗涤纤维消化率不受生物碱浓度影响（P＞0.10）。在消化动力学方面观察到差异；具体而言，随着生物碱浓度增加，不可消化酸性洗涤纤维（IADF）填充量和流出量呈线性下降（P＜0.10）。然而，这些差异可能归因于日粮中IADF浓度的差异。生理变量（心率、呼吸频率以及直肠、耳部和尾根皮肤表面温度）不受生物碱浓度影响（P＞0.10）。每周测定的血清催乳素浓度随着日粮生物碱浓度增加有降低趋势（P＜0.10）。在研究结束时，给每头阉牛注射100微克促甲状腺激素释放激素（TRH）。所有阉牛对TRH刺激均有反应（P＜0.10）；然而，基础日粮生物碱浓度之间的反应无差异（P＞0.10）。（摘要截短至250字）
