Smith R D, Hansel W, Coppock C E
J Dairy Sci. 1975 Nov;58(11):1708-12. doi: 10.3168/jds.S0022-0302(75)84772-2.
Responses of plasma corticoids to adrenocorticotropic hormone (.32 U/kg body weight) administered during early lactation were measured in dairy cattle consuming large amounts of concentrate feeds and one of the following forage diets: alfalfa-timothy hay plus corn silage, alfalfa-timothy hay crop silage plus corn silage, or corn silage. Concentrations of plasma corticoids increased to maximum in all groups within 60 to 90 min. Concentrations remained at near maximum for 4 to 5 h and then declined to baseline. Maximum corticoid concentrations following adrenocorticotropic hormone injection differed among forage treatment groups. Responses of corn silage and hay crop silage groups (46.7 +/- 1.1 and 50.1 +/- 2.4 ng/ml) did not differ but were less than those in the hay group (65.5 +/- 2.9 ng/ml). Response measured as area under the curve of plasma corticoid response also differed among forage treatments: hay 443 +/- 17 h (ng/ml) is greater than hay crop silage 334 +/- 34 is greater than corn silage 245 +/- 36. Results are discussed in terms of stress susceptibility in dairy cattle consuming diets containing large amounts of silage.
对采食大量精饲料并采用以下一种粗饲料日粮的奶牛，测定了其在泌乳早期注射促肾上腺皮质激素（0.32单位/千克体重）后血浆皮质醇的反应：苜蓿-梯牧草干草加玉米青贮料、苜蓿-梯牧草青贮作物加玉米青贮料或玉米青贮料。所有组的血浆皮质醇浓度在60至90分钟内升至最高。浓度在近最高水平维持4至5小时，然后降至基线。注射促肾上腺皮质激素后的最大皮质醇浓度在不同粗饲料处理组间存在差异。玉米青贮料组和青贮作物组（46.7±1.1和50.1±2.4纳克/毫升）的反应无差异，但低于干草组（65.5±2.9纳克/毫升）。以血浆皮质醇反应曲线下面积衡量的反应在不同粗饲料处理间也存在差异：干草组443±17小时（纳克/毫升）大于青贮作物组334±34大于玉米青贮料组245±36。根据采食含大量青贮料日粮的奶牛的应激易感性对结果进行了讨论。
