The effect of stress on the plasma ACTH and cortisol concentrations after administration of Arginine-Vasopressin (AVP) in cattle

本试验研究了应激对牛注射精氨酸加压素（AVP）后血浆促肾上腺皮质激素（ACTH）和皮质醇浓度的影响。社会应激的影响将5头荷斯坦小母牛（Mx）与5头干奶母牛和3头对照母牛（Cn）混合。在混合前3天，混合后3、7、14、21天，在注射AVP前，注射后10、30、60和120分钟，通过静脉穿刺收集血液样品用于血浆ACTH和皮质醇的测定。以混群前后牛与牛之间的攻击胜负数来评价各母牛的优势值（ADV）变化。混合后MX的ADV降低。血浆促肾上腺皮质激素浓度的MX天之间没有差异。AVP给药后皮质醇浓度的增加MX混合后变小，但Cn在实验日之间没有差异。ADV与血浆ACTH浓度呈显著正相关（p <0.05）。热应激的影响5头小母牛（HS）在夏季晴天（最高气温38.0 ℃）在室外围场中饲养2h，5头（NM）在畜棚中饲养（34.7 ℃）。分别于注射AVP前、注射后5、15、30、60和120分钟静脉穿刺采血，测定血浆ACTH和皮质醇。血浆ACTH浓度在治疗之间没有差异。当排除两个异常数据时，HS组5和I5min的ACTH浓度倾向于低于NM组（p = 0.06）。血浆皮质醇浓度没有显着差异HS和MN。这些结果表明，血液中的ACTH和皮质醇浓度的牛AVP管理后，可能会改变在应激条件下。该方法可用于牛应激的评价。

The effect of stress on the plasma concentration of ACTH and cortisol after administration of Arginin-Vasopressin (AVP) on cattle was investigated.Experiment 1. The effect of social stressFive Holstein heifers (Mx) were mixed into the herd of 5 dry cows and 3 heifers in original heifer herd as control (Cn). On 3 days before mixing, 3, 7, 14, 21 days after mixing, blood samples of hefers were collected by venous puncture just before AVP injection, 10, 30, 60 and 120 min. after the injection for plasma ACTH and cortisol measurements. Change of dominance value (ADV) of each heifer was evaluated by win and loss numbers of aggressions between cattle before and after mixing. ADV of MX decreased after mixing. Plasma ACTH concentrations of MX were not different between days. The increase of cortisol concentration after AVP administration of MX became smaller after mixing but that of Cn did not differ among experimental days. ADV had significantly positive correlation with plasma ACTH concentration (p ≦ 0.05).Experiment 2. The effect of heat stress5 heifers (HS) were kept in a outside paddock during 2 hours on a sunny summer day (highest air temperature, 38.0 ℃) and 5(NM) were in barn (34.7 ℃). Blood samples of hefers were collected by venous puncture just before AVP injection, 5, 15, 30, 60 and 120 min. after the injection for plasma ACTH and cortisol measurements. Plasma ACTH concentration did not differ between the treatments. When the two abnormal data were eliminated, ACTH concentration on 5 and I5min tended to be lower in HS than that in NM (p = 0.06). Plasma cortisol concentration did not differ between HS and MN.These results show that blood ACTH and cortisol concentrations of cattle after AVP administration may change under stressful conditions. This method may be useful to evaluate the stress of cattle.