Herskin Mette S, Munksgaard Lene, Ladewig Jan
Danish Institute of Agricultural Sciences, Department of Animal Health and Welfare, Research Center Foulum, P.O. Box 50, DK-8830 Tjele, Denmark.
Physiol Behav. 2004 Dec 15;83(3):411-20. doi: 10.1016/j.physbeh.2004.08.027.
Effects of acute stressors on behavioral, adrenocortical and nociceptive responses were examined in 24 dairy cows kept in tie stalls, using 15 min of social isolation in novel surroundings (ISOL), fixation by the head in the home stall (FIX) and the provision of novel neighbors/stall (NEIGH) as acute stressors as well as a control treatment (CON). Each cow was exposed to one treatment daily in a balanced order. All stressors led to signs of hypoalgesia as indicated by slower (P=0.01) and reduced responses (P<0.10) toward nociceptive laser stimulation after exposure to the acute stressors. ISOL, however, had stronger effects than FIX or NEIGH. ISOL or FIX led to increased plasma concentration of cortisol (P<0.001), whereas NEIGH or CON did not. The behavioral responses were affected by treatments as well, as shown by decreased rumination for all stressors (P<0.001) and a gradual increase in active avoidance from CON to NEIGH to FIX (P<0.001). Furthermore, exposure to NEIGH led to increased exploration (P<0.001), aggression (P<0.10) and self-grooming behavior (P<0.10) compared with the CON treatment. The results suggest that nociceptive changes are part of responses toward acute stress in dairy cows. The nociceptive changes, however, were not direct reflections of the adrenocortical or behavioral responses toward the acute stressors. Therefore, quantification of nociceptive changes, in combination with behavioral and physiological registrations, can be one way to broaden the range of biological systems, considered for the study of animals under stress, and thereby extend the understanding of responses toward acute stress in dairy cows.
在24头饲养于拴系牛舍的奶牛中，研究了急性应激源对行为、肾上腺皮质和伤害感受反应的影响。采用在新环境中15分钟的社会隔离（ISOL）、在牛舍内固定头部（FIX）以及提供新邻居/牛舍（NEIGH）作为急性应激源，并设置了对照处理（CON）。每头奶牛每天按平衡顺序接受一种处理。所有应激源均导致伤害感受减退迹象，表现为暴露于急性应激源后对伤害性激光刺激的反应变慢（P = 0.01）且反应减弱（P < 0.10）。然而，ISOL的影响比FIX或NEIGH更强。ISOL或FIX导致皮质醇血浆浓度升高（P < 0.001），而NEIGH或CON则未导致这种情况。行为反应也受到处理的影响，所有应激源均导致反刍减少（P < 0.001），并且从CON到NEIGH再到FIX，主动回避行为逐渐增加（P < 0.001）。此外，与CON处理相比，暴露于NEIGH导致探索行为增加（P < 0.001）、攻击行为增加（P < 0.10）和自我梳理行为增加（P < 0.10）。结果表明，伤害感受变化是奶牛对急性应激反应的一部分。然而，伤害感受变化并非对急性应激源的肾上腺皮质或行为反应的直接反映。因此，结合行为和生理记录对伤害感受变化进行量化，可能是拓宽用于研究应激状态下动物的生物系统范围的一种方法，从而扩展对奶牛急性应激反应的理解。
