Jens Malmkvist

Effects of individual versus group stabling on social behaviour in domestic stallions

Domestic horses (Equus caballus) are typically kept in individual housing systems, in which they are deprived of physical contact. In order to study the effects of social restrictions on behaviour in young horses, nineteen 2-year-old stallions were housed either singly (n=7), or in groups of three (n=12) for 9 months. Subsequently, the stallions were released into two separate 2 ha enclosures according to treatment, and recordings were made on social interactions and nearest neighbours during a 6-week-period, 28 h per week. Previously group stabled stallions frequently had a former group mate as their nearest neighbour (P=0.001), whereas previously singly stabled stallions did not associate more with their former box neighbours, to whom physical contact was limited by bars during the previous treatment. The nearest neighbour was more frequently recorded to be within one horselength of singly stabled than of group stabled stallions (P=0.005). More aggressive behaviour was recorded in the group of previously singly stabled stallions, i.e. bite threats (P=0.032), whereas group stabled stallions tended to make more use of subtle agonistic interactions (displacements, submissive behaviour). Singly stabled stallions also responded to the 9 months of social deprivation by significantly increasing the level of social grooming (P<0.001) and play behaviour (P<0.001), when subsequently interacting freely with other horses. The increased occurrence may relate to a build-up of motivation (a rebound effect), as well as to external factors, such as playful pasture companions and the increased space allowance of the pasture. It is concluded that 2-year-old domestic stallions are sensitive to social deprivation and that stabling has long-term effects, lasting 6 weeks at least, on the social behaviour in stallions.

Generalization of fear in farm mink, Mustela vison, genetically selected for behaviour towards humans

Abstract Mink offspring from two genetic lines, selected over 10 generations for confident (C) or fearful (F) reaction towards humans, were exposed to six different tests. The aim was to investigate whether this behavioural selection in mink has affected their reaction in other potentially fear-eliciting situations. A total of 192 naive mink, males and females, were tested over 6 weeks. C-mink had a shorter latency to get near and establish exploratory contact with a human than F-mink. F-mink maintained 6–10 times the distance to a human than C-mink. Similarly, C-mink had a markedly shorter latency than F-mink to approach and make contact with a novel object. C-mink also manipulated the object sooner and more often. In encounters with unfamiliar mink, C-mink were quicker to approach and establish nonaggressive contact than F-mink. C-mink had a shorter latency than F-mink to enter tubes within an X maze, and were more likely to visit these tubes. In contrast, F-mink made the most visits to other parts of the maze; number of visits may not, however, reflect just exploration. When presented with novel food, F-mink changed their behaviour more often than C-mink, indicating a higher degree of behavioural conflict. C-mink were also less hesitant than F-mink to approach and eat the novel food. In conclusion, offspring from a confident breeding line reacted with more exploratory behaviour than offspring from a fearful breeding line. Mink lines selected for behaviour towards humans thus generalized their fear responses across several social and nonsocial situations. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Effects of a calm companion on fear reactions in naive test horses

REASON FOR PERFORMING STUDY In fear-eliciting situations, horses tend to show flight reactions that can be dangerous for both horse and man. Finding appropriate methods for reducing fearfulness in horses has important practical implications. OBJECTIVES To investigate whether the presence of a calm companion horse influences fear reactions in naive subject horses. HYPOTHESES The presence of a habituated (calm) companion horse in a fear-eliciting situation can reduce fear reactions in naive subject horses, compared to subject horses with a nonhabituated companion (control). METHODS Minimally handled (n = 36), 2-year-old stallions were used, 18 as subjects and 18 as companions. Companion horses (n = 9) were habituated to an otherwise frightening, standardised test stimulus (calm companions), whereas the rest (n = 9) of the companion horses remained nonhabituated (control companions). During the test, unique pairs of companion and subject horses were exposed to the test stimulus while heart rate and behavioural responses were registered. Subsequently, subject horses were exposed to the stimulus on their own (post test). RESULTS Subject horses, paired with a calm companion horse, showed less fear-related behaviour and lower heart rate responses compared to subject horses with control companions. Results from the post test suggest that the difference between treatment groups remained in the subsequent absence of companion horses. CONCLUSIONS AND POTENTIAL RELEVANCE It appears possible to reduce fear reactions in young, naive horses by allowing them to interact with a calm companion horse in fear-eliciting situations.

Influence of thermal environment on sows around farrowing and during the lactation period

Our objective was to investigate the effects of floor heating duration (HEAT: 35°c for 12 or 48 h) after birth of first piglet (BFP) under different room temperatures (ROOM: 15°C, 20°C, 25°C) on sows during farrowing and lactation. The study included 8 to 11 repetitions for each combination of ROOM and HEAT. There were no treatment effects on indicators of birth problems (duration of parturition, interbirth intervals, umbilical cord lactate concentration), BW changes of the sow, and litter size and weight until weaning. Sows at 15°C compared with 20°C and 25°C spent more time nest building (P = 0.015). The feed intake was reduced the first 7 d after farrowing in sows at 25°C (P = 0.014); however, both daily feed intake (P = 0.018) and water consumption (P < 0.001) of these warm sows exceeded that at lower temperatures during the last part of the lactation. Sows at 15°C received more medical treatments until weaning at heat = 48 h only (ROOM and HEAT interaction, P = 0.005). Room temperature influenced prefarrowing water consumption (25°C > 20°C and 15°C; P < 0.017), sow surface temperature (15°C < 20°C < 25°C; P < 0.001), respiration rate (25°C > 20°C > 15°C; P < 0.001), and rectal temperature during the first 12 h after bfp (15°C < 25°C; P = 0.009); additionally, long floor heating duration (HEAT = 48 h) increased the respiration rate by 50% d 1 and 2 after bfp (p < 0.001). The proportion of lying time on the unheated slatted floor increased with room temperature (P < 0.001) and, transiently, also for the heat = 48 h treatment 13 to 48 h after BFP (P < 0.001). The majority of piglets (82% to 95%) were born on the heated solid floor, regardless of room temperature (P = 0.46). Sows spent approximately twice as much time standing and walking at 15°C during 13 to 48 h after BFP at HEAT = 12 h only (ROOM and HEAT interaction; P = 0.002). In conclusion, long-term indicators of reduced sow performance were unaffected by room temperature, probably because the farrowing and lactating sows in the current pen design were able to perform thermoregulatory behavior and successfully adapt to room temperatures between 15°C and 25°C.

The development of on-farm welfare assessment protocols for foxes and mink: the WelFur project

The WelFur project aims at the development of on-farm welfare assessment protocols for farmed foxes (the blue fox [Vulpes lagopus], the silver fox [Vulpes vulpes]) and mink (Neovison vison). The WelFur protocols are based on Welfare Quality® (WQ) principles and criteria. Here, we describe the WelFur protocols after two years of developmental work. Reviews for each of the 12 WQ welfare criteria were written for foxes and mink to identify the welfare measures that have been used in scientific studies. The reviews formed the basis for potential measures to be included in the WelFur protocols. All measures were evaluated for their validity, reliability and feasibility. At present, we have identified 15 fox and 9 mink animal-based (or outcome-based) welfare measures, and 11 and 13 input-based (resource-based or management-based) measures. For both foxes and mink, each of the four WQ principles is judged by at least one criterion, and seven out of the 12 criteria include animal-based measures. The protocols will be piloted in 2012. Using the WQ project and protocols as a model has been a fruitful approach in developing the WelFur protocols. The effects of the WelFur protocols will provide benchmarks from which the welfare of animals on European fur farms can be assessed.

Stress and stereotypic behaviour in mink (Mustela vison): a focus on adrenocortical activity.

We examined whether female mink with low (LS) and high (HS) occurrence of stereotypic behaviour differ in their adrenocortical activity in baseline conditions or in response to immobilisation (Experiment 1), handling, adrenocorticotropic hormone (ACTH) challenge (Experiment 2) and excretion of circulating cortisol (Experiment 3). Faeces are the predominating excretory route of cortisol (83%), with peak concentrations after 4.2 h (urine: 3.4 h). Faecal cortisol metabolites (FCMs) reflected changes in relation to handling/ACTH challenge. In Experiment 1 (n = 162), HS mink had approximately 54% higher baseline level of FCM than LS mink (P < 0.001), with markedly elevated FCM on the days after an immobilisation stressor. In Experiment 2 (n = 48), LS and HS mink did not differ in adrenocortical activity after an ACTH challenge. However, HS mink reacted more in response to handling, evident in the FCM level 4–20 h after the handling (P = 0.001). In Experiment 3 (n = 16), the excretion of infused 3H-cortisol did not differ between LS and HS mink. Stereotypic behaviour is concurrent with higher baseline concentrations of FCM, which cannot be explained by a greater adrenocortical reactivity or a different excretion of the circulating cortisol. Instead, we conclude that mink with a high level of stereotypic behaviour have a greater perception of stress, or increased sensitivity to stressors at the pituitary level.

Effects of thermal environment on hypothalamic-pituitary-adrenal axis hormones, oxytocin, and behavioral activity in periparturient sows.

Provision of additional floor heating (33 to 34 degrees C) at birth and during the early postnatal hours is favorable for newborn piglets of domestic sows (Sus scrofa). We investigated whether this relatively high temperature influenced sow behavior and physiology around farrowing. One-half of 28 second-parity pregnant sows were randomly chosen to be exposed to floor heating 12 h after onset of nest building and until 48 h after birth of the first piglet (heat treatment), whereas the rest of the sows entered the control group (control treatment) with no floor heating. Hourly blood sampling from 8 h before and until 24 h after the birth of the first piglet was used for investigation of temporal changes in plasma concentrations of oxytocin, cortisol, and ACTH. In addition, occurrence and duration of sow postures were recorded -8 to +48 h relative to the birth of the first piglet. There was a clear temporal development in sow behavior and hormone concentrations (ACTH, cortisol, and oxytocin) across parturition (P < 0.001), independent of treatment. In general, hormone concentrations increased from the start to the end of farrowing. The observed oxytocin increase and peak late in farrowing coincided with the passive phase where sows lie laterally with an overall reduced activity. Floor heating increased the mean concentration of cortisol (P = 0.02; estimated as 29% greater than in controls) and tended to increase the mean concentration of ACTH (P = 0.08; estimated as 17% greater than in controls), but we did not find any treatment effect on mean oxytocin concentrations, the course of parturition, or the behavior of sows. Behavioral thermoregulation may, however, have lost some function for the sows because the floor was fully heated in our study. In addition, exposure to heat decreased the between-sow variation of plasma oxytocin (approximately 31% less relative to control) and ACTH (approximately 46% less relative to control). Whether this decreased variation may be indicative of acute stress or linked to other biological events is unclear. In conclusion, inescapable floor heating (around 33.5 degrees C) may be considered a stressor for sows around farrowing, giving rise to elevated plasma concentrations of cortisol, but without concurrent changes in oxytocin or behavioral activity.

Rein tension acceptance in young horses in a voluntary test situation

REASONS FOR PERFORMING THE STUDY During riding, horses are frequently exposed to pressure from the rider, e.g. through the bit and reins, but few studies have investigated at which point rein tension becomes uncomfortable for the horse. OBJECTIVES To investigate how much rein tension young inexperienced horses are willing to accept in order to obtain a food reward; whether the tension acceptance changes during 3 consecutive test days; and whether rein tension correlates with the expression of conflict behaviour and heart rate. HYPOTHESES Pressure-naïve horses will apply only little rein tension in the first voluntary trial, but their acceptance will gradually increase. High levels of rein tension will lead to expression of conflict behaviour and increases in heart rate. METHODS Fifteen 2-year-old, bridle-naïve mares were encouraged to stretch their head forward (across a 0.95 m high metal bar) to obtain a food reward in a voluntary test situation. On each test day, each horse was exposed to 2 control sessions (loose reins), an intermediate and a short rein session (1 min/session). Rein tension, heart rate and behaviour were recorded. RESULTS The horses applied significantly more tension on the first day (mean rein tension: 10.2 N), compared to the second and third test day (Day 2: 6.0 and Day 3: 5.7 N). The horses showed significantly more conflict behaviour in the short rein treatment. There was no treatment effect on heart rate. CONCLUSIONS AND POTENTIAL RELEVANCE The horses applied the highest rein tension on the first day, and apparently learned to avoid the tension, rather than habituate to it. Rein tension correlated with expression of conflict behaviour, indicating that the horses found the tension aversive. Further studies should focus on the correlation between rein tension and conflict behaviour in ridden horses.

Proportion of insoluble fibre in the diet affects behaviour and hunger in broiler breeders growing at similar rates

With a view to alleviate the feeling of hunger in broiler breeders, different types of fibre sources were used in high-fibre diets to increase feed quantity while limiting growth to industry recommended levels. Using scatter feeding, three diets (C1: commercial control diet, 1 × fibre content, 80% insoluble fibre (ISF); H2: 2 × fibre content, 89% ISF; and L2: 2 × fibre content, 71% ISF) were each fed to 10 groups of 16 broiler breeder chickens. Similar growth rates were obtained on different quantities of food with all birds reaching commercial target weight at 15 weeks of age. In a hunger test, birds fed C1 ate significantly faster and showed a higher compensatory feed intake than birds on diets H2 and L2, indicating that the two high-fibre diets did reduce the level of hunger experienced by the birds. Behavioural observations carried out at 14 weeks of age showed high levels of tail pecking in birds fed C1 and almost none in birds fed L2, whereas birds fed H2 were intermediate. Stereotypic pecking at fixtures was seen twice as frequently in birds fed C1. Birds on diet L2 displayed behavioural signs indicative of discomfort, and the high water usage on this diet created problems with litter quality. Birds on diet H2 continued to show foraging behaviour throughout the day, and were more frequently engaged in dust bathing and other comfort behaviour. This experiment indicates that high-fibre diets can alleviate the feeling of hunger currently experienced by broiler breeders, and a high ratio of ISF may improve the well-being of the birds.

Avoiding hypothermia in neonatal pigs: effect of duration of floor heating at different room temperatures.

The effect of different farrowing room temperatures (15, 20, or 25°C), combined with floor heating (FH) at the birth site, on the postnatal rectal temperature of pigs, use of creep area, and latency to first colostrum uptake was investigated with 61 litters born by loose-housed sows. Pig rectal temperature was measured at birth, as well as at 0.25, 0.5, 1, 1.5, 2, 3, 4, 12, 24, and 48 h after birth. The drop in rectal temperature from birth to 0.5 h postpartum was less (P<0.05) at room temperature of 25°C compared with 20 and 15°C. Minimum rectal temperature was less (P<0.001) at 15°C than either 20 or 25°C, and the time it took for rectal temperature to increase above 37°C was longer (P<0.05) when room temperature was 15°C than 20 and 25°C. Rectal temperatures at 24 (P<0.001) and 48 h (P<0.05) postpartum were also lower at room temperature of 15°C than 20 and 25°C. Duration of FH (12 or 48 h) did not influence (P>0.28) the rectal temperature at 24 or 48 h after birth. More pigs used the creep area 12 to 60 h after birth of the first pig at a room temperature of 15°C with 12 h FH compared with all other treatments. During the latter part of this period, more pigs stayed in the creep area also at 20°C with 12 h FH. After 60 h, more pigs (P<0.01) used the creep area at low compared with high room temperatures (15°C>20°C>25°C). Odds ratio of pigs dying before they had suckled was 6.8 times greater (P=0.03) at 15 than 25°C (95% CI of 1.3 to 35.5), whereas the odds ratio of dying during the first 7 d was 1.6 greater (P=0.05) for 48 vs. 12 h of FH (95% CI of 1.0 to 2.57), mainly due to more pigs being crushed. In conclusion, FH for 48 h was no more favorable than 12 h for pigs because the risk of hypothermia was equal in the 2 treatments, and the risk of dying increased with the longer FH duration. Increasing the room temperature to 25°C reduced hypothermia and the risk of pigs dying before colostrum intake.