Markus Stauffacher

Enrichment-dependent differences in novelty exploration in rats can be explained by habituation

In rats, exploratory activity and emotional reactivity towards novel stimuli reflect independent biological functions that are modulated differently by rearing experiences. Environmental enrichment is known to improve performance in exploratory tasks, while having inconsistent effects on emotionality. This study examined the effect of environmental enrichment on the behaviour of rats in two exploratory tasks. Male rats were reared under one of four conditions, differing in social and non-social complexity. At 9 weeks of age, exploration of a novel open field, and exploration of novel objects in the same open field following 24 h habituation, was assessed. Differences in social and non-social complexity of the rearing environment had inconsistent effects on exploration in the novel open field. In contrast, when rats were faced with novel objects in an otherwise familiar environment, exploration habituated faster with increasing stimulus complexity of the non-social environment. The social environment had no effect on this latter test. These findings indicate that environmental enrichment affects exploratory activity primarily through its effect on habituation to novelty. This effect depends on relative stimulus complexity of the rearing environment, but is independent of social factors. The present results further suggest that aversive tasks can obscure the expression of enrichment-dependent differences in habituation to novelty.

Prevention of stereotypy in laboratory mice: Effects on stress physiology and behaviour

According to the coping hypothesis, the adaptive significance of stereotypies in barren housing conditions may lie in their potency to attenuate the deleterious consequences of chronic stress. Present evidence from experimental studies is ambiguous. When Zur:ICR mice were selectively prevented from stereotypic wire gnawing at the cage lid, the previous amount of stereotyped behaviour after a short-term decrease in activity was compensated by variable active behaviour on the cage floor. This change in behaviour was associated with a short-term elevation of serum corticosterone concentrations 24 h after stereotypy prevention. However, 3 days later corticosterone levels were back at pretreatment base levels. Both behavioural and physiological short-term effects were caused by the impact of prevention on behavioural organization. They disappeared as soon as new habits were established, even though they were not stereotyped. In contrast to the predictions of the coping hypothesis, prevention of stereotypy had no significant effects on chronic measures of both the sympathetic-adrenal-medullary system and the hypothalamus-pituitary-adrenal system. Thus, there is no evidence that stereotypic wire gnawing reduces chronic stress in Zur:ICR mice. This implies that coping with stress is not a general aspect of cage-induced stereotypic behaviour.

Bite and kick injuries in horses: Prevalence, risk factors and prevention

REASON FOR PERFORMING STUDY Studies on the prevalence and predisposing factors of bite and kick injuries in horses have not been reported in a population-based data sample. OBJECTIVES To investigate the prevalence of bite and kick injuries in horses and associated risk factors in a representative sample of horses in Switzerland. METHODS A questionnaire on the incidence of disease and injury, which included the frequency of bite and kick injuries and their association with breed, housing, use and feeding regime, was sent to 2559 horse owners randomly selected throughout Switzerland. RESULTS The data of 2912 horses with 897 disorders diagnosed by a veterinarian were analysed. There were 231 injuries, 50 (21.6%) caused by a bite or kick from another horse; this number corresponded to 5.6% of all diseases and injuries and concerned only 1.7% of all the horses evaluated. Warmblood, Thoroughbred and Arabian horses had a 4.3 times higher risk of bite or kick injuries than horses of other breeds. Eighteen per cent of injuries were associated with a change in housing management and occurred regardless of whether horses were kept in groups permanently or sporadically. CONCLUSIONS AND POTENTIAL RELEVANCE A stable group hierarchy and a housing system that provides adequate space and is adapted to horse-specific behaviour are important factors in prevention and kick and bite injuries.

Physical condition at weaning affects exploratory behaviour and stereotypy development in laboratory mice

Laboratory mice of the ICR strain develop two morphologically distinct forms of stereotypy in the post-weaning period when kept under standard housing conditions. Wire-gnawing develops from single bites at the cage-lid during exploratory climbing whereas jumping originates from exploratory rearing at the cage wall. In a recent study nude mutants of ICR that were physically retarded around the age of stereotypy development performed more rearing but less climbing just after weaning and subsequently developed more jumping but less wire-gnawing than ICR mice (Würbel, H., Stauffacher, M. and von Holst, D. 1996. Ethology 102: 371-385). The two source behaviour patterns, climbing and rearing, could represent alternative strategies serving the same goal (e.g. exploration of external stimuli, escape). Since the ability to climb may depend on physical strength, preference for either of these two patterns may be determined by physical condition to some extent. As a consequence, the prefered pattern may determine the later form of stereotypy. To test these two hypotheses, 48 male ICR mice were assigned to three groups of 16 each. One group was prematurely weaned at day 17 to mimic physical retardation, the others were weaned at the standard weaning age of 20 days and divided into two groups of high and low weaning weight. Premature weaning was associated with a shift in the relative proportions of climbing and rearing towards rearing. Although heavy males showed most climbing and least rearing, weaning weight did not significantly affect performance of these two patterns. Subsequently, all mice developed stereotypic wire-gnawing but none of them showed stereotypic jumping. Although weaning age affected the performance of the two source behaviour patterns in the predicted way, the differences may not have been large enough to cause different forms of stereotypy. However, both, premature weaning and low weaning weight resulted in higher stereotypy performance when adult.

Influence of floor surface and access to pasture on claw health in dairy cows kept in cubicle housing systems

In this study, the effects on the claw health of dairy cows of three different floor types and access to pasture were investigated on 35 farms. The farms were fitted with a given floor type in the indoor walking area of a cubicle housing system: a solid rubber, mastic asphalt or slatted concrete floor. Because we chose farms on which the given floor type was in good condition, the data presented show what can be achieved on these types of floors under ideal circumstances. Cows on half of the farms per floor type had access to pasture during the grazing period. Each farm was visited three times at approx. 6-month intervals at the end of the winter indoor-housing period and at the end of the summer period, i.e. after the period with access to pasture on half of the farms. During each visit, the claw health of the same 10 cows per farm was assessed on the occasion of routine claw trimming. The proportion of cows with haemorrhages increased from mastic asphalt to rubber and slatted concrete floors. A lower proportion of cows kept on mastic asphalt was affected by white-line fissures and needed intermittent claw-trimming, an indicator for lameness. Cows housed in cubicle systems with slatted concrete floors were at the lowest risk of having heel-horn erosions. Access to pasture was associated with a lower incidence of slight white-line fissures and dermatitis digitalis. A higher proportion of cows with sole haemorrhages and sole ulcers were found on all floor types at the end of the summer period than at the end of the winter indoor-housing period. Floor type did not influence the presence of sole ulcers and deep white-line fissures. In conclusion, the effect of floor type on claw health was slight, and none of the investigated floor types was clearly superior to the others. Access to pasture was not effective in reducing the presence of most types of claw lesions associated with the floor type used in the indoor walking area.

Kälberkastration: Eine Befragung von Schweizer Mutterkuhhaltern

In fall 2004, a survey of a representative sample of 1185 Swiss suckler beef farmers was carried out by questionnaire (return rate 51.9%). 32.7% of the respondents castrated their calves without the help of a veterinarian, 37.8% mandated a veterinarian to carry out the castrations and 29.4% did not castrate their bull calves at all. On average, 8 calves were castrated per farm and year at an average age of 7 days when the castration was carried out by a farmer or 34 days when the castration was carried out by a veterinarian. Almost all farmers castrated their calves with the rubber ring, and a majority considered no other method as feasible. 73.9% of the veterinarians used the Burdizzo technique, 14.9% applied rubber rings, and 11.2% performed a surgical procedure. 22.6% of the farmers and 85.4% of the veterinarians used sedation; local anaesthesia was performed in 32.1% of the castrations carried out by farmers and in 84.5% of the castrations carried out by veterinarians. 65.7% of the farmers were concerned by the change of the Swiss Animal Protection Ordinance (2001), when pain relief became mandatory. 47.6% of these farmers changed their castration routine: 53.1% now mandated a veterinarian, 33.0% used sedation or local anaesthesia and 8.9% abandoned castration of their calves. 59.8% of the farmers intended to participate in a future course for laymen, to study and train the technique of local anaesthesia for castration. Castration of their calves is for many suckler beef farmers an inevitable husbandry procedure. The political goal, that all calves shall be castrated with local anaesthesia can only be reached when livestock owners are informed about the distress caused by the castration and convinced of the benefit of the local anaesthesia.Veterinarians are important information carriers in this process. The implementation also produces work, be it the more complex castration procedure or the education of the farmers who want to carry out the local anaesthesia themselves.

Frequency of diseases and injuries in the Swiss horse population

Through a written questionnaire, which was sent to a representatively distributed and randomly selected sample of Swiss horse owners, data of 2912 horses and ponies were acquired to extrapolate prevalence data of health disorders. General questions about the horse and associated factors of housing and use, as well as questions about the current health status and the occurrence of diseases and injuries had been asked. 718 horses (24.7% of the sample) had been examined by a veterinarian within the 12 months prior to the survey. Orthopaedic and traumatic disorders (41.5%) had the largest proportion, followed by gastrointestinal--(27.1%) and respiratory (14.0%) diseases. Half of the lameness cases occurred as a direct consequence of a injury. The injuries were associated with pasture/paddock (38.1%), kicking and biting (21.6%), boxstall (7.8%), terrain and hacking (13.4%), training (3.5%), competition (3.5%), transportation (3.0%) or other circumstances (9.1%). A change in feeding management up to 4 weeks before development of a colic episode occurred in 26.5% of all colic cases. In 13.8% of all respiratory cases the same disease was diagnosed in other horses in the same barn. 8.1% of all cases had to be treated surgically, 6.7% required hospitalization for several days. Information about diagnostic or therapeutic procedures was related to specific disease categories. In 25.6% of all cases diagnosed by a veterinarian alternative therapeutic methods were used either in addition to traditional medicine or exclusively.Through a written questionnaire, which was sent to a representantively distributed and randomly selected sample of Swiss horse owners, data of 2912 horses and ponies were acquired to extrapolate prevalence data of health disorders. General questions about the horse and associated factors of housing and use, as well as questions about the current health status and the occurrence of diseases and injuries had been asked. 718 horses (24.7 % of the sample) had been examined by a veterinarian within the 12 months prior to the survey. Orthopaedic and traumatic disorders (41.5 %) had the largest proportion, followed by gastrointestinal (27.1 %) and respiratory (14.0 %) diseases. Half of the lameness cases occurred as a direct consequence of an injury. The injuries associated with pasture/paddock (38.1 %), kicking and biting (21.6 %), boxstall (7.8 %), terrain and hacking (13.4 %), training (3.5 %), competition (3.5 %), transportation (3.0 %) or other circumstances (9.1 %). A change in feeding management up to 4 weeks before development of a colic episode occurred in 26.5 % of all colic cases. In 13.8 % of all respiratory cases the same disease was diagnosed in other horses in the same barn. 8.1 % of all cases had to be treated surgically, 6.7 % required hospitalization for several days. Information about diagnostic or therapeutic procedures was related to specific disease categories. In 25.6 % of all cases diagnosed by a veterinarian, alternative therapeutic methods were used either in addition to traditional medicine or exclusively.