The benzodiazepine brotizolam reduces fear in calves exposed to a novel object test.

The present study examined the effects of the intravenous administration of the anxiolytic drug brotizolam on the behavioral and physiological responsiveness of calves to novelty in a dose response fashion. Holstein Friesian heifer calves (39-41 weeks of age; body weight 200-300 kg) received an intravenous injection of either a vehicle control (12 calves) or one of four doses of brotizolam (8 calves per dose): 0.0125, 0.05, 0.2 and 0.8 mg/100 kg body weight. They were then individually subjected to a 'combined' test involving exposure to a novel environment (open field, OF) for 5 min followed by the sudden introduction of a novel object (NO) that remained in place for a further 10 min. Behavioral, heart rate and plasma cortisol responses were recorded in all animals. Compared to vehicle treatment, the highest dose of brotizolam dose-dependently and significantly increased the time spent in locomotion and the distance travelled near the NO, as well as the time spent in contact with the NO. In addition, post-test plasma cortisol concentrations changed in a dose-dependent manner over time: they decreased between 0 and 10 min after the test in calves that had received the two highest doses of brotizolam, whereas they increased in vehicle-treated and low-dosage calves. There were no effects of brotizolam on vocalization or locomotion during the OF phase of the test or on vocalization following introduction of the NO. These findings strongly support the notion that interaction with a novel object in a novel arena represents a behavioral index of fear and fearfulness in calves, and that vocalization and locomotion in an OF reflect other independent characteristics.

Coping styles in animals: current status in behavior and stress-physiology.

This paper summarizes the current views on coping styles as a useful concept in understanding individual adaptive capacity and vulnerability to stress-related disease. Studies in feral populations indicate the existence of a proactive and a reactive coping style. These coping styles seem to play a role in the population ecology of the species. Despite domestication, genetic selection and inbreeding, the same coping styles can, to some extent, also be observed in laboratory and farm animals. Coping styles are characterized by consistent behavioral and neuroendocrine characteristics, some of which seem to be causally linked to each other. Evidence is accumulating that the two coping styles might explain a differential vulnerability to stress mediated disease due to the differential adaptive value of the two coping styles and the accompanying neuroendocrine differentiation.

Stress enhanced reduction in peripheral blood lymphocyte numbers in dairy cows during endotoxin-induced mastitis.

Two groups of Holstein dairy cows, which showed either high- (HC; n = 8) or low (LC; n = 10) plasma cortisol concentrations in response to a psychological stressor (novel-environment test) in their first lactation, were used 1 year later for studying the effects of psychological stress on various aspects of the host defence during endotoxin-induced mastitis. Social isolation was used as a stressor; endotoxin was used to activate the host defence. HC-cows appeared to be more stressed by the experimental procedure than LC-cows. One hour after having been isolated, rectal temperature increased (+0.59 degrees C) in HC- but not in LC-cows. Handling, related to the intra-mammary administration of endotoxin, induced a higher increase in cortisol concentration in HC- than in LC-cows 1 h after injection. In addition, HC-cows vocalised significantly more frequently (595 +/- 222) than LC-cows (81 +/- 24) between 1.5 and 9.5 h after isolation. Between 3 and 5.5 h after endotoxin-treatment, cortisol concentrations increased profoundly in both LC- and HC-cows and peaked at 24.6 +/- 3.8 and 22.8 +/- 3.1 ng ml(-1), respectively. The rise in plasma cortisol concentration was associated with a decrease in the number of circulating lymphocytes between 0 and 8 h post injection (PI). Between 8 and 10 h PI, the number of circulating lymphocytes in HC-cows further decreased (40%) to 1.58x10(6) cells ml(-1) and remained so until 21 h PI. This was not the case with the LC-cows. The results show that a differing sensitivity of dairy cows to environmental stressors is associated with a significant difference in the number of circulating leukocytes following intra-mammary administration of endotoxin during a period of social isolation. The results further suggest that, apart from adrenocortical hormones, other factors related to general stress-responsiveness modulate the number of peripheral lymphocytes in dairy cows during endotoxin-induced mastitis. During environmental stress, these factors may enhance endotoxin-induced reduction in circulating lymphocyte numbers, particularly in cows that are sensitive to environmental stressors. As to the clinical relevance of these differences in stress responsiveness, no differences between LC- and HC-cows were found in disease incidence nor in duration of a disease episode during both the 1st and 2nd lactation. In the 2nd lactation. HC-cows tended to produce less milk than LC-cows.

Effects of repeated jugular puncture on plasma cortisol concentrations in loose-housed dairy cows.

In three experiments, the effects of venipuncture on plasma cortisol concentrations were studied in loose-housed dairy cows. In Exp. 1, two blood samples were collected 18 min apart on three alternate days from 20 dairy cows for studying their adrenocortical response to a single venipuncture. To further evaluate the effect of cows anticipating venipuncture, in Exp. 2, 15 dairy cows were sequentially venipunctured once daily on 12 successive days in a randomized order in groups of five, starting 15 min apart. In Exp. 3, 10 primiparous cows were used on three alternate days to study habituation to serial sampling (i.e., collection of five blood samples by venipuncture, 15 min apart). In cows accustomed to handling, jugular puncture did not affect cortisol concentrations in plasma collected 18 min later. Average daily cortisol concentrations varied between 2.07 +/- .38 and 3.81 +/- .56 ng/mL in the first (t = 0) and between 1.43 +/- .15 and 2.61 +/- .72 ng/mL in the second (t = 18) blood samples. Likewise, when cows were sampled sequentially once a day, the order of sampling between and within groups did not influence (P > .05) plasma cortisol concentrations. In contrast, primiparous dairy cows that were less used to being handled showed an average increase in cortisol concentrations when five samples were collected by venipuncture 15 min apart. During successive sampling sessions, however, the cows did not decrease or increase plasma cortisol concentrations in response to repeated serial sampling at the group level (P > .05). Between individuals, the maximum effect of repeated venipuncture on cortisol concentrations (4.5 to 22.6 ng/mL), the time at which the effect reached its maximum (30 to 60 min), and the consistency of the response pattern over successive series varied largely. The results of this study show that in cows that were accustomed to handling and to being restrained, baseline cortisol concentrations can be measured in single blood samples that are collected by jugular puncture within 1 min after first approaching the cow. When successive blood samples need to be collected within 15 to 20 min, jugular puncture may induce an increase in cortisol concentration, which seems to depend on the handling experience of the animals and on individual differences.

Transgenesis may affect farm animal welfare: a case for systematic risk assessment.

This paper considers (potentially) harmful consequences of transgenesis for farm animal welfare and examines the strategy of studying health and welfare of transgenic farm animals. Evidence is discussed showing that treatments imposed in the context of farm animal transgenesis are by no means biologically neutral and may compromise animal health and welfare. Factors posing a risk for the welfare of transgenic farm animals include integration of a transgene within an endogenous gene with possible loss of host gene function (insertional mutations), inappropriate transgene expression and exposure of the host to biologically active transgene-derived proteins, and in vitro reproductive technologies employed in the process of generating transgenic farm animals that may result in an increased incidence of difficult parturition and fetal and neonatal losses and the development of unusually large or otherwise abnormal offspring (large offspring syndrome). Critical components of a scheme for evaluating welfare of transgenic farm animals are identified, related to specific characteristics of transgenic animals and to factors that may interact with the effects of transgenesis. The feasibility of an evaluation of welfare of transgenic farm animals in practice is addressed against the background of the objectives and conditions of three successive stages in a long-term transgenic program. Concrete steps with regard to breeding and testing of transgenic farm animals are presented, considering three technologies to generate transgenic founders: microinjection, electroporation and nuclear transfer, and gene targeting including gene knockout. The proposed steps allow for unbiased estimations of the essential treatment effects, including hemi- and homozygous transgene effects as well as effects of in vitro reproductive technologies. It is suggested that the implementation of appropriate breeding and testing procedures should be accompanied by the use of a comprehensive welfare protocol, specifying which parameters to monitor, at which stages of the life of a farm animal, and in how many animals. Some prerequisites and ideas for such a protocol are given. It is anticipated that systematic research into the welfare of farm animals involved in transgenesis will facilitate the use of the safest experimental protocols as well as the selection and propagation of the healthiest animals and, thereby, enable technological progress that could be ethically justified.

Farm animal welfare research in interaction with society.

Over the last 30 years concern about farm animal welfare has increased and has become a public issue in the Netherlands. Public discussion has stimulated research in this field, financed by both government and industry. Dutch society in general and consumers of animal products in particular, want to see high standards of welfare for production animals. Good animal welfare has gradually gained more impact in the total quality concept of the product. This will encourage scientists to continue to analyse the welfare status of animals and to come up with innovative solutions for the remaining problems. At ID-Lelystad much effort is put into farm animal welfare research. This research includes for example, the development of behavioural tests for quantifying and interpreting fear in cattle, investigations into the effects of dietary iron supply and a lack of roughage on behaviour, immunology, stress physiology, and pathology in veal calves, studies of the ontogeny of tail biting in finishing pigs and feather pecking in laying hens as well as evaluation of the welfare effects of automatic milking in dairy cows. The results of these projects contribute to concrete improvements in animal husbandry and expertise and support policy making and legislation. The animal industry as well as retailers should aim at the further implementation of this knowledge and to specify welfare standards to guarantee consumer acceptance of animal production.