Abstract: Plasma cortisol is largely bound to corticosteroid-binding globulin (CBG), which regulates its bioavailability by restricting exit from capillaries. Levels of CBG may be altered by several factors including stress and this can influence the amount of cortisol reaching cells. This study investigated the effect of social instability on plasma concentrations of CBG, total and free (not protein bound) cortisol in horses. Horses new to our research herd ('newcomers') were confined in a small yard with four dominant resident horses for 3-4 h daily for 3-4 (n = 5) or 9-14 (n = 3) days. Jugular blood was collected in the mornings from newcomers before the period of stress began ('pre-stress'), and then before each day's stress. Residents were bled before stress on the first and thirteenth day. Residents always behaved aggressively towards newcomers. By the end of the stress period, all newcomers were subordinate to residents. In newcomers (n = 8) after 3-4 days of social stress, CBG binding capacity had fallen (P = 0.0025), while free cortisol concentrations had risen (P = 0.0016) from pre-stress values. In contrast, total cortisol did not change. In residents, CBG had decreased slightly but significantly (P = 0.0162) after 12 days of stress. Residents and newcomers did not differ in pre-stress CBG binding capacity, total or free cortisol concentrations. However, by the second week of stress, CBG binding capacity was lower (P = 0.015) and free cortisol higher (P = 0.030) in newcomers (n = 3) than in residents. Total cortisol did not differ between the groups. In conclusion social stress clearly affected the adrenal axis of subordinate newcomer horses, lowering the binding capacity of CBG and raising free cortisol concentrations. However, no effect of stress could be detected when only total cortisol was measured. Therefore, to assess adrenal axis status accurately in horses, it is essential to monitor the binding capacity of CBG and free cortisol concentrations in addition to total cortisol levels.

Abstract: A severe multi-systemic form of equid herpesvirus-1 infection is described in an adult zebra stallion. There was multifocal necrotizing rhinitis, marked hydrothorax and pulmonary oedema, with viral antigen expression in degenerating epithelial cells, local endothelial cells and intravascular leucocytes of the nasal mucosa and lung. Specific localization of EHV-1 infection was seen in the testes and epididymides, including infection of Leydig cells and germinal epithelium, which would have facilitated venereal shedding of virus in life. The case provided a unique opportunity to study hitherto undescribed aspects of the pathogenesis of naturally occurring EHV-1 infection in the male equine genital tract. Restriction digests of the isolate demonstrated a pattern similar to that of EHV-1 isolates previously recovered from aborted zebra and onager fetuses.

Abstract: Personality ratings of 34 spotted hyenas (Crocuta crocuta) were made by 4 observers who knew the animals well. Analyses suggest that (a) hyena personality traits were rated with generally high reliability; (b) 5 broad dimensions (Assertiveness, Excitability, Human-Directed Agreeableness, Sociability, and Curiosity) captured about 75% of the total variance; (c) this dimensional structure could not be explained in terms of dominance status, sex, age, or appearance; and (d) as expected, female hyenas were more assertive than male hyenas. Comparisons with previous research provide evidence for the cross-species generality of Excitability, Sociability, and especially Assertiveness. Discussion focuses on methodological issues in research on animal personality and on the potential contributions this research can make for understanding the biological and environmental bases of personality.

Abstract: A group of experienced riders who qualified for the German riding badge 9.5 years ago answered a questionnaire pertaining to injuries during jumping, dressage and cross-country riding, as well as handling the horse. During riding 69% of the persons had had 187 injuries and while handling the horse 52% had had 124 injuries. Fractures and contusions were the most-frequent injuries; most riding injuries were located in the upper extremities and shoulder while handling mainly in the hands and feet. The number of injuries was comparable in jumping, dressage or cross-country riding. The time engaged in jumping was about one-third of the other types of riding, but the injuries were more severe. While handling the horse the number of injuries relative to the time spent during the activity were higher but less complicated. No change in safety precautions had been implemented by 67% of the persons injured. The injury rate for equestrians is relatively low both in handling the horse and during riding. The frequent fractures and contusions may be reduced by following the required safety regulations.