Applied Animal Behaviour Science

Editorial Board

2010-08-01

Cognitive ability and awareness in domestic animals and decisions about obligations to animals

Donald M. Broom — 2010-06-14

Abstract: Observation of behaviour, especially social behaviour, and experimental studies of learning and brain function give us information about the complexity of concepts that animals have. In order to learn to obtain a resource or carry out an action, domestic animals may: relate stimuli such as human words to the reward, perform sequences of actions including navigation or detours, discriminate amongst other individuals, copy the actions of other individuals, distinguish between individuals who do or do not have information, or communicate so as to cause humans or other animals to carry out actions. Some parrots, that are accustomed to humans but not domesticated, can use words to have specific meanings. In some cases, stimuli, individuals or actions are remembered for days, weeks or years. Events likely to occur in the future may be predicted and changes over time taken into account. Scientific evidence for the needs of animals depends, in part, on studies assessing motivational strength whose methodology depends on the cognitive ability of the animals.Recognition and learning may be associated with changes in physiology, behaviour and positive or negative feelings. Learning and other complex behaviour can result in affect and affect can alter cognition. The demonstration of cognitive bias gives indications about affect and welfare but should be interpreted in the light of other information. All of the information mentioned so far helps to provide evidence about sentience and the level of awareness. The term sentience implies a range of abilities, not just the capacity to have some feelings. The reluctance of scientists to attribute complex abilities and feelings to non-humans has slowed the development of this area of science.Most people consider that they have obligations to some animals. However, they might protect animals because they consider that an animal has an intrinsic value, or because of their concern for its welfare. In social species, there has been selection promoting moral systems that might result in behaviours such as attempts to avoid harm to others, collaboration and other altruistic behaviour. An evaluation of such behaviour may provide one of the criteria for decisions about whether or not to protect animals of a particular species. Other criteria may be: whether or not the animal is known as an individual, similarity to humans, level of awareness, extent of feelings, being large, being rare, being useful or having aesthetic quality for humans. Cognitive ability should also be considered when designing methods of enriching the environments of captive animals.

Effects of Burdizzo castration on CO2 laser induced thermal nociception of Holstein–Friesian calves of different ages

2010-06-14

Abstract: The objective was to investigate the effects of Burdizzo castration on the thermal nociception (stress-induced hypoalgesia) of Holstein–Friesian bull calves of different ages. Calves castrated at 5.5mo of age were compared with either intact calves of the same age, or calves castrated at 1.5, 2.5, 3.5, and 4.5mo of age (n=10 calves/treatment). Treatments were conducted on the same day for all calves. The baseline surface skin temperatures on the caudal part of metatarsi, and the latency of the calves to perform hind leg withdrawal (i.e., thermal nociception threshold) in response to a CO2 laser beam applied on the same area were measured 72h before, and 12, 24 and 48h after treatment. The thermal nociception threshold varied inversely with the baseline skin temperature (pooled correlations, r=−0.45, −0.31 and −0.48 at 12, 24 and 48h, respectively; P<0.01). There were no differences (P>0.05) in the skin temperatures between castrated and intact calves at 5.5mo of age. Calves castrated at 1.5mo-old had consistently lower skin temperatures than all other castrated calves throughout the study. These calves had markedly increased skin temperatures following castration, while the opposite trend was observed in older castrated calves, and no change was observed in intact calves. At −72h, the 1.5mo-old calves had higher thermal nociception thresholds than older calves. In all calves, the thermal nociception threshold increased after treatment. Calves castrated at 5.5mo of age tended to display higher thermal nociception threshold than intact calves. However, variations in the initial skin temperature accounted for these differences between treatments or interactions between time and treatment. In conclusion, the laser-based thermal nociception assay can be influenced by the surface skin temperature of the hind legs and the age of animals, particularly in calves less than 2mo of age which have lower skin temperatures and longer latency to respond to the laser. Burdizzo castration increased the skin temperature of 1.5mo-old calves, but had the opposite effects on older calves. Within the temporal limits of this study, no conclusive evidence was found to support the presence of acute stress-induced hypoalgesia following castration.

Reliability and feasibility of selected measures concerning resting behaviour for the on-farm welfare assessment in dairy cows

Gudrun Plesch, Nina Broerkens, Simone Laister, Christoph Winckler, Ute Knierim — 2010-06-18

Abstract: Resting is important for regeneration and disturbances are welfare relevant as they may be associated with insufficient recuperation, frustration, discomfort or pain and increased risk for health problems such as lameness or lesions. As part of the Welfare Quality® project this study aimed to identify feasible and reliable resting measures in terms of inter-observer reliability (IOR) and consistency of results per farm over time that can be included in an on-farm welfare assessment protocol. Altogether 15 measures were investigated. They were recorded during three farms visits (approximately 60 and a further 120 days apart) on 35 farms in Austria and Germany with cubicle, deep litter and tie stall systems. Seven measures occurred too infrequently (<1/h and 1% respectively) to allow reliable recording within a limited observation time. IOR was generally acceptable to excellent (Spearman's r=0.7–1.0), except for ‘collision during lying down’ with a PABAK of 0.2 (n=15, observed on farm). However, after improvement of the definition IOR was good (0.78, n=65, observed from videos). Only three measures were acceptably repeatable over time, ‘duration of lying down’ (Kendall's W=0.78 for a minimum of 6 recorded occurrences), ‘percentage of collisions during lying down’ (W=0.95) and ‘percentage of cows lying partly or completely outside lying area’ (W=0.87). These measures are evaluated as suitable animal based welfare measures regarding resting behaviour in the framework of an on-farm welfare assessment protocol. They can be easily and reliably recorded within 2h during a farm visit require only a short training period and show sufficient consistency of results over time. They, moreover, allow distinction between different housing systems. However their sensitivity with regard to differences between individual farms and within farms over time needs further investigation.

Foraging in a heterogeneous environment—An experimental study of the trade-off between intake rate and diet quality

2010-06-11

Abstract: Among the factors determining the choice of feeding sites by herbivores, the rate of intake of net energy and nutrients is a major one. For grazers, patches of tall grasses are ingested faster, but are digested less fully because of their high fibre contents; conversely, short grass is highly digestible but allows only low intake rates. Herbivores therefore face a trade-off between the quantity and the quality of their food. Little empirical information is available to test whether optimisation models of patch selection are applicable to horses. An experiment was therefore designed where the trade-off between sward height and quality was explored to test explanatory models based on rates of nutrient acquisition (digestible dry matter, energy and/or protein intake rates). Three groups of two 2-year-old saddle horses were grazed on pasture managed to produce three swards differing in both height and quality (vegetative to reproductive stages). They were offered binary choices in a Latin-square design to assess preferences; daily intake was measured to determine the consequences of their choices. Instantaneous intake rates (IIRs) were determined from bite rates at pasture, and bite mass estimated using trays indoors. The taller sward matured during the experiment, so the quality differences between swards increased. The horses selected the taller sward in the first period, and the shorter alternatives in the following ones. The rates of digestible dry matter (DM) and net energy intake were always higher on the tall swards; digestible protein was the best predictor of the horses’ choices. Patch selection thus depended on the nutritional context: when digestible protein was not limiting, the horses selected patches where food was ingested faster, and when protein supplies declined, they maximised their protein intake rate. Preferences were however partial: as the shorter swards allowed higher rates of digestible protein intake but lower net energy than the taller swards, the horses may have been balancing their protein and energy intake by feeding on both swards; alternative explanations are discussed.

Discrimination between conspecific odour samples in the horse (Equus caballus)

Becky Hothersall, Patricia Harris, Lotta Sörtoft, Christine J. Nicol — 2010-06-07

Abstract: Behavioural observations suggest that smell is important in social discriminations between horses but balanced studies of this capacity are lacking. We used a habituation–discrimination procedure to investigate the ability of horses to distinguish between pairs of odour samples from different individuals. In Study 1, separate tests were conducted for urine, faeces or fleece fabric previously rubbed on the coat (to pick up body odour samples (BOS)) and donor pairs differed in sex, and age. 10 pregnant mares each underwent three tests, one per sample type. A test consisted of three successive 2-min presentations of a sample from Individual A with a simultaneous presentation of a sample from Individual B during the final presentation. Doubly repeated measures ANOVA indicated a main effect of sample type on investigative response (df=2, f=7.98, P=0.004): durations were longer for BOS than for urine or faeces but habituation across trials was most consistent for urine. In the final presentation, mares demonstrated discrimination by investigating the novel urine sample (B) more than the repeated sample (novel: median 8.0s, IQR=10; repeated: median 2.5s, IQR=6; z=−2.558, P=0.008). In Study 2, urine samples from castrated male donors were used and neither mares nor their 4-month-old foals discriminated between samples from different individuals in the final presentation. The findings suggest that urine odour may contain some information that horses can use to discriminate between conspecifics. This may be limited to the level of broad categories such as sex or reproductive status; further investigation is needed to reveal what functional information can be transmitted and what compounds are involved.

Domesticated dogs (Canis familiaris) react to what others can and cannot hear

2010-07-05

Abstract: Recent research suggests some nonhuman primates (e.g., chimpanzees, rhesus macaques) consider what others hear when acting in competitive situations. We explored whether dogs living in private homes or sourced from an animal shelter would show this same predilection. Following an inhibition task where dogs (Canis familiaris) were commanded not to take a treat left on a plate by a human, we presented subjects with the opportunity to take food from one of two containers. These containers were located within the proximity of a human gatekeeper who was either looking straight ahead or not looking at the time of choice. One container was silent when food was inserted or removed while the other was noisy. Among pet dogs (20 total; 10 in each condition) randomly assigned to the Looking or Not Looking condition, four subjects approached the silent container in the Looking condition (binomial test: P=0.8) while 10 approached the silent container in the Not Looking condition (binomial test: P=0.004). We compared pet dogs’ pattern of performance between conditions using a chi-square test for independence, which indicated that dogs significantly preferred the silent container only in the Not Looking condition (, P=0.003). This outcome suggests dogs preferentially attempted to retrieve food silently only when silence was germane to obtaining food unobserved by the human gatekeeper. Interestingly, dogs sourced from a local animal shelter evidenced similar outcomes. Among shelter dogs (20 total; 10 in each condition) randomly assigned to the Looking or Not Looking condition, four subjects approached the silent container in the Looking condition (binomial test: P=0.8) while nine approached the silent container in the Not Looking condition (binomial test: P=0.02). We compared shelter dogs’ pattern of performance between conditions using a chi-square test for independence, which indicated that dogs significantly preferred the silent container only in the Not Looking condition (, P=0.02). This result suggests shelter dogs, like pet dogs, preferentially tried to retrieve food silently only if silence was relevant to obtaining food unobserved by a human gatekeeper. This result conflicts with other recent data suggesting that shelter dogs perform more poorly than pet dogs in tasks involving human social cues.

Exposure to video images between 3 and 5 weeks of age decreases neophobia in domestic dogs

Jolanda J.T.M. Pluijmakers, David L. Appleby, John W.S. Bradshaw — 2010-06-17

Abstract: Restricted experience in early life is known to contribute to long-lasting predispositions to fear and anxiety in mammals. It is commonplace for young domestic dogs not to experience many features of the environment in which they will spend their adult lives until after 8 weeks of age: simulations of that environment presented before 8 weeks might therefore reduce subsequent fear and anxiety. A series of experiments tested whether fearful and exploratory behaviour up to 8 weeks of age is reduced by exposure to audiovisual playback between 3 and 5 weeks of age. First, it was demonstrated that puppies between 3 and 5 weeks of age do respond to video images. Second, the reactions of puppies, exposed to audiovisual playbacks for 30min per day for 14 days between 3 and 5 weeks old, to test objects in both familiar and unfamiliar environments, were compared with those of control, unexposed puppies; the unexposed puppies visited most of the objects significantly more frequently than did the exposed puppies. Third, another sample of puppies given the same treatments was tested at 7–8 weeks of age; the unexposed puppies were significantly more fearful than the exposed, and also tended to visit the objects more frequently. Audiovisual simulations therefore appear to be worthy of further investigation as a way of enhancing coping strategies in dogs.

Do different competition strategies affect social preference and behaviour in silver fox vixens (Vulpes vulpes)?

Anne Kathrine Akre, Anne Lene Hovland, Morten Bakken — 2010-06-07

Abstract: Among mammals, social ranking is generally thought to affect the outcome of disputes over preferred, limited or future resources. Therefore, we should expect individuals’ preference for conspecifics to be affected by their own and other individuals’ competition capacity. Here, we investigated the social preference and behavioural response in farmed silver fox vixens (Vulpes vulpes) towards unfamiliar vixens of different competition capacities, measured by their ability to compete for and defend a limited food resource, in a choice test. We found that low competition capacity vixens spent significantly less time in front of the high competition capacity vixens (2647±600s) compared to the time they spent in front of the low competition capacity vixens (6041±877s, P<0.05). In addition, the low competition capacity vixens spent significantly less time in front of the high competition capacity vixens (2647±600s) compared to what the high competition capacity vixens did (4215±657s, P=0.03). This suggests that low competition capacity vixens perceive high competition capacity vixens as a greater potential threat than high competition capacity vixens do. Time spent in social exploration, resting, sitting and performing aggressive behaviours in front of a stimulus animal were also affected by competition capacity of the foxes. The vixens were also retreating significantly more from the high competition capacity vixens (2±0.8 times) than from the low competition capacity vixens (0.4±0.4 times, P=0.03), possibly reflecting that the high competition capacity vixens were more offensive than the low competition capacity vixens. Our results contribute to the knowledge of social behaviour in this species, and may have implications for the social housing environment of the farm foxes.

The effects of resource distribution on behaviour in pair housed silver fox vixens (Vulpes vulpes) subsequent to mixing

Anne Kathrine Akre, Anne Lene Hovland, Morten Bakken — 2010-06-07

Abstract: In nature, the way essential resources are distributed is recognized as a potentially important factor influencing the frequency of aggressive interactions between animals. This knowledge is rarely taken into consideration when designing housing environments for social groups of farm animals. Adult farmed silver foxes (Vulpes vulpes) are often housed singly, but previous studies have demonstrated that vixens show a motivation for social contact in particular periods of the year and housing in social groups may therefore act as an alternative housing procedure for foxes. However, grouping unfamiliar animals may result in elevated levels of aggression due to competition for resources and thus affect welfare negatively. In the present study we investigated how housing environments with the same space and resources, but with different resource distributions affected the behaviour of adult vixens housed in pairs. A total of 40 vixens were housed in pairs in two coupled cages (2.00m×1.10m×0.75m) with either two nest boxes and two food trays (treatment 1) or one nest box and one food tray (treatment 2) from 18 months of age. The occurrence of aggressive behaviour, play behaviour and synchronous resting was recorded throughout the day (i.e. every third hour for 15min during 24h) on day 1, day 5, day 19 and day 33 after mixing. In addition, the frequency of physical aggression was recorded for 75min around feeding time. Body weight gain and wounds were also recorded on day 25 after mixing. The results showed that there had been more severe aggression in treatment 2 during the days after mixing due to higher frequency of physical aggression around feeding time (treatment 1: 0.6±0.21 times, treatment 2: 2.9±0.99 times, P=0.06), more wounds (treatment 1: 3 of 10 pairs, treatment 2: 8 of 10 pairs, P=0.03) and less body weight gain (P=0.03) compared to treatment 1. The observed aggression levels throughout the day decreased with subsequent observations days for both aggressive displays (P<0.01) and chase behaviour (P=0.04), indicating that it takes between 5 and 19 days to establish a stabile social relationship within a vixen pair. There was an increase in social (P=0.09) and locomotor play (P=0.03) as well as synchronous resting (P<0.001) with subsequent days after mixing, suggesting that the stress by being mixed with an unfamiliar conspecific is decreasing with time. In both treatments, there was a decrease in object play (P<0.001) with subsequent days after mixing, however vixens in treatment 2 showed in general more object play than vixens in treatment 1 (4.3±0.60 scores vs. 2.5±0.47 scores respectively). To conclude, we found that different resource distributions affected wounds, body weight gain and physical aggression during feeding in pair housed silver fox vixens. The elevated aggression levels the first days after mixing may affect vixens’ welfare negatively, however, the increase of social play after mixing suggests that social housing also have positive effects on welfare. The resource distribution of highly valued resources should be taken into account when designing the future social housing system for farmed foxes.

Minimizing disturbance to wildlife by tourists approaching on foot or in a car: A study of kangaroos in the Australian rangelands

Isabelle D. Wolf, David B. Croft — 2010-06-28

Abstract: Approaching wildlife to attain a closer viewing experience is common amongst visitors to natural areas. We examined how tourists approach free-living kangaroos during encounters in a popular tourism destination in South Australia. We then simulated the typical properties of approaches to quantify the behavioural reactions of two kangaroo species—the Red Kangaroo (Macropus rufus) and the Euro (M. robustus erubescens). We also accounted for the disturbance context such as varying environmental conditions (time of day, cover, wind speed) and other factors (species, sex class, grouping) that potentially modify the kangaroos’ flight response.Approach varied by access (on-trail, off-trail), transport (on-trail: hiking, driving; off-trail: hiking) and approach style (on-trail: tangential/continuous, tangential/stop-and-go; off-trail: direct/continuous, direct/stop-and-go, direct/stop-and-go/talking, tangential/zigzag/stop-and-go). On-trail, 53% of kangaroos took flight when the closest distance to them was approached whilst (by design) all subjects off-trail took flight. The mean (±1 SE) flight initiation distance (FID) was significantly shorter following an on-trail (78±2.7m) than an off-trail approach (90±2.7m). Kangaroos fled less often (41% vs. 75%) and spent more time in maintenance activities (40% vs. 10%) if approached in a vehicle than on foot. The mean FID and flight length (FL) after approach on foot was reduced when made in a stop-and-go fashion without talking. Euros fled at a significantly shorter FID with a shorter FL than Red Kangaroos, and so did females with obvious pouch-young compared to females with young-at-foot. FID was shortest if the approach was made in the evenings, the habitat provided cover and the day was calm.The results suggest that wildlife tourists should be educated to the best choice of approach behaviour and viewing conditions to reduce aversive reactions in kangaroos and mediate closer observations to the visitors’ greater satisfaction and the kangaroos’ better welfare. Our study also shows the benefit of a two-stage approach where the detailed observation of human behaviour serves as a prerequisite to an experimental study on wildlife response.

Stereotypies and environmental enrichment in captive southern hairy-nosed wombats, Lasiorhinus latifrons

2010-06-24

Abstract: A captive colony of 12 (4♂, 8♀) wombats, Lasiorhinus latifrons, was used to investigate stereotypic behaviour in this species and determine the beneficial effects of enrichment on wombat behaviour and wellbeing. The wombats were housed in four groups of 1♂ and 2♀, each in a separate enclosure and subjected to two different treatments: (1) enrichment, where the animals received two types of enrichment along with a treatment diet and (2) no-enrichment, where the animals received no such enrichment and were fed the standard diet. Each treatment was implemented twice, for a period of 12 weeks, in a pseudo-random order. Wombat behaviour was remotely observed via digital video surveillance. Each wombat was observed for 12×24-h periods during each treatment rotation with behaviours (both major and minor) being recorded at 5-min intervals over each 24-h sampling period. Eight (67%) of the captive wombats displayed a singular stereotypy in the form of straight-line pacing, boundary pacing, figure-8 pacing or wall climbing. Mean daily time spent stereotyping was variable between individuals (P<0.01) ranging from 61 to 129min (4–9%), with a mean value of 86.9±6.7min (6.0±0.5%). There was a significant (P≤0.02) increase in foraging (by 333%, from 7 to 30min/day) and exploration (by 13%, from 70 to 79min/day) in response to enrichment. However, enrichment had no effect (P≥0.13) on the time spent stereotyping or being inactive. Enrichment may have been unsuccessful at reducing stereotypic behaviour in the captive wombats due to the wrong type of enrichment being provided (i.e. the underlying problem motivating this behaviour may not have been addressed) or because the expression of this behaviour had become resistant to change, i.e. habit-like and/or perseverative. Although stereotyping and inactivity were not reduced by enrichment, it still resulted in improved welfare as the animals were given more stimulus diversity, had more choice in behaviour options, had more opportunity to interact with their environment and were able to express a larger amount of natural behaviour.