Effect of early androgen treatment on subsequent social behavior in heifers

About the inconvenience of handling mixed-breed herds; aspects of social behavior as a potential source of stress and economic losses

The objective of this study was to assess aspects of the social behavior of a mixed-breed herd of beef cows as a potential source for stress and economic losses. Angus (AN; N = 10), Brahman (BR; N = 10), and Senepol (SE; N = 10) cows were assigned to two groups (N = 15 each containing equal breed numbers) on separate pastures. Agonistic interactions (win/loss) during feeding were recorded daily for 45 days. Dominance values were estimated as the proportion of individuals dominated to total herdmates. From this, individuals were placed into social categories based upon linear ranking as follows: dominants (D), intermediate (I), and subordinates (S). Breed influenced (P < 0.01) social category, with SE cows being dominants (P < 0.05) over AN and BR cows. Interactions between AN and BR cows were less (P < 0.0005) than interactions between AN and SE (53 vs 140, respectively). Within breeds, BR (152) and SE (182) cows had more (P < 0.0005) agonistic interactions than AN (107) cows. Although apparently influenced by breed, agonistic interactions occurred more frequently (P < 0.005) between social categories than within social categories (814 vs 310, respectively). Dominant cows were involved in more agonistic interactions with cows from different social categories than were intermediate and subordinate cows (P < 0.0005). However, intermediate (100) and subordinate (157) cows generated more (P < 0.0005) agonistic interactions within their own social category than dominant cows (53). It was concluded that, in mixed-breed herds, breed influences both social organization and agonistic interactions which could be considered as potential sources of stress and economic losses.

Fear reactions of domestic sheep confronted with either a human or a human-like model

Fear reactions of ewes towards a human, a human-like model or a control (plastic cylinder 1.95 m high) were studied using a test previously designed and validated, in which 16 behavioural parameters have been interpreted as indicators of fear (e.g. a relatively long time spent away from the stimulus) or absence of fear (e.g. a relatively long time spent eating near the stimulus). In a first experiment, 18 animals were individually confronted with each of the 3 stimuli for 4 min (in a counter-balanced order). The results indicated that both the human and the human-like model elicited greater fear reactions than did the control, and that the former two stimuli did not differ in their fear-eliciting properties. In a second experiment designed to determine if the animals become aware of a difference between the human and the model over time, 32 animals were confronted successively with each of the two stimuli for 8 min. Although there was some habituation towards both stimuli, there was no difference between them even at the end of the test period. These results suggest that a model could be appropriate in experiments involving human presence (at least for a short duration) and would allow for better standardization. It can also be hypothetized that exposing animals to a model would lead to familiarization which might in turn help reduce fear of human beings and thus improve ease of handling and welfare.

Behavioural characteristics of two dairy breeds of cows selected (Hérens) or not (Brune des Alpes) for fighting and dominance ability

Two breeds of dairy cattle, one selected for intra-specific fighting and dominance ability (Hérens, H), the other not selected for this behavioural trait (Brune des Alpes, BA), submitted to the same management techniques, were compared with respect to their social behaviour (dominance, agonistic behaviour, social tolerance, social motivation, social distance), fear reactions, ease of handling and physiological correlates.As expected, cows from the H breed were dominant over the BA cows, they were also less fearful either in response to novel objects or in surprise effect tests and had higher social distances at pasture.On the contrary, H cows were less aggressive in undisturbed groups and more tolerant in a food-competition test than BA cows. There were no differences between the two breeds either in aggressive acts in encounters with unfamiliar animals, or in persistence in conflict situations.Furthermore, H cows were less easy to handle in a standardised test, and tended to be less socially motivated than BA cows. Lastly, H cows had higher plasma testosterone levels, and tended to present a lower increase in plasma cortisol level after a surprise effect than BA cows.Thus, the breeders' selection for fighting and dominance ability in H breed appears to have led to several behavioural and hormonal changes.

Psychological moods and subjectively perceived behavioral and somatic changes accompanying anabolic-androgenic steroid use

To assess physiological and psychological states accompanying anabolic-androgenic steroid use, male weight lifters 1) were interviewed regarding their physical training and the patterns and effects of any drug use; 2) completed a written physical and medical history questionnaire, a Profile of Mood States questionnaire, and the Buss-Durkee Hostility Inventory; and 3) were physically examined, including a blood sample and urinalysis. Subjects were divided into current anabolic-androgenic steroid users (N = 12), previous users (N = 14), and nonusers (N = 24). Current and previous users reported the following changes associated with anabolic-androgenic steroid use: increases in enthusiasm, aggression, and irritability; changes in insomnia, muscle size, muscle strength and density; faster recovery from workouts and injuries; and changes in libido. We were unable to confirm these interview and physical and medical history questionnaire responses using standardized and well-accepted psychological inventories. There were no significant differences among groups for any Profile of Moods factor, total mood disturbance, total Buss-Durkee Hostility Inventory score, or any subscale. For current users, there were no significant correlations between either total weekly drug dose or length of time on the current cycle of anabolic-androgenic steroids and any individual scale of the Profile of Mood States, Buss-Durkee Hostility Inventory, Profile of Mood States total mood disturbance, or composite Buss-Durkee Hostility Inventory score. Furthermore, anabolic-androgenic steroid users did not differ in their responses on these inventories from nonusers or from general population norms.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens, progestagens and agonistic behaviour: a review

The relationship between androgens, progestagens and agonistic behaviour is reviewed. Most literature concerned the effects of hormones on aggression; little information was available on hormonal influences on fear. Difference in aggression levels between males and females may be explained by assuming the existence of a gender difference in motivation, which, among other factors, is controlled by androgen and progestagen levels in peripheral blood. Androgens and progestagens are metabolised mainly by 5 alpha-reductase in the target organs. In the brain, aromatisation of testosterone also plays a role. The metabolites of testosterone may exert the same organising and activating influence as testosterone on juvenile and adult brain tissue, respectively. In some animal species testosterone secretion appears to be influenced by social and environmental variables. Conversely, alterations in plasma androgen levels have been found to affect behaviour. Dominant and/or aggressive individuals tend to show higher plasma testosterone levels than submissive and/or less aggressive animals. Among other mechanisms, competitive inhibition of androgen action at a central level, by progestagens acting as antagonists of androgens, may be important.

Synthetic Anabolic-Androgenic Steroids: A Plea for Controlled Substance Status

One way to combat the abuse of anabolic-androgenic steroids is to reclassify them as controlled substances under federal law. The author contends that the widespread abuse of steroids, their habit-forming properties, and their other adverse effects are good reasons for reclassification.