Validating owner-reporting of feather condition of pet Psittaciformes using photographs

Reporting of outcome variables by caregivers in welfare studies is commonplace but is open to subjective bias and so requires validation. Biases can occur in either direction: familiarity with an animal allows a deeper insight into welfare problems, but also can lead to reticence in admitting that an animal in one's care is experiencing problems. Here, we aim to validate owner-reporting of plumage condition of pet parrots, including those with self-inflicted feather-damaging behaviour (FDB), by comparing owners' scores of feather condition with those of two independent raters, blind to the owners' and each other's assessments. We surveyed pet parrot owners to collect data on basic demographics and feather condition, and requested four standardised photographs of birds. We received 259 responses (17% of the 1,521 people contacted); 78 sets of images of appropriate quality for assessment by raters were provided. Mean percentage agreement between owners' and raters' scores was mostly fair to substantial using Cohen's kappa; however, raters scored a greater proportion of feather damage than did owners. Overall, our results indicate owner-reporting of feather condition, including FDB, to be generally reliable and consistent with independent assessment of photographs. As the use of photographs can be limited by image quality, a failure to represent the long-term state of a parrot, and the potential for incorrect recording if assessed without relevant information (eg on moulting), this evidence that owner-reports can be reliable opens the door for larger-scale surveys of the extent of welfare-relevant problems.

Post-weaning social and cognitive performance of piglets raised pre-weaning either in a complex multi-suckling group housing system or in a conventional system with a crated sow

We studied the social and cognitive performance of piglets raised pre-weaning either in a conventional system with a sow in a farrowing crate (FC) or in a multi-suckling (MS) system in which 5 sows and their piglets could interact in a more physically enriched and spacious environment. After weaning at 4 weeks of age, 8 groups of 4 litter-mates per pre-weaning housing treatment were studied under equal and enriched post-weaning housing conditions. From each pen, one pair consisting of a dominant and a submissive pig was selected, based on a feed competition test (FCT) 2 weeks post-weaning. This pair was used in an informed forager test (IFT) which measured aspects of spatial learning and foraging strategies in a competitive context. During individual training, submissive (informed) pigs learned to remember a bait location in a testing arena with 8 buckets (the same bucket was baited in a search visit and a subsequent relocation visit), whereas dominant (non-informed) pigs always found the bait in a random bucket (search visits only). After learning their task, the informed pigs' individual search visit was followed by a pairwise relocation visit in which they were accompanied by the non-informed pig. Effects of pre-weaning housing treatment were not distinctly present regarding the occurrence of aggression in the FCT and the learning performance during individual training in the IFT. During paired visits, informed and non-informed pigs changed their behaviour in response to being tested pairwise instead of individually, but MS and FC pigs showed few distinct behavioural differences.

Risks associated with preweaning mortality in 855 litters on 39 commercial outdoor pig farms in England

A prospective longitudinal study was carried out on 39 outdoor breeding pig farms in England in 2003 and 2004 to investigate the risks associated with mortality in liveborn preweaning piglets. Researchers visited each farm and completed a questionnaire with the farmer and made observations of the paddocks, huts and pigs. The farmer recorded the number of piglets born alive and stillborn, fostered on and off and the number of piglets that died before weaning for 20 litters born after the visit. Data were analysed from a cohort of 9424 liveborn piglets from 855 litters. Overall 1274 liveborn piglets (13.5%) died before weaning. A mixed effect binomial model was used to investigate the associations between preweaning mortality and farm and litter level factors, controlling for litter size and number of piglets stillborn and fostered. Increased risk of mortality was associated with fostering piglets over 24h of age, organic certification or membership of an assurance scheme with higher welfare standards, farmer's perception that there was a problem with pest birds, use of medication to treat coccidiosis and presence of lame sows on the farm. Reduced mortality was associated with insulated farrowing huts and door flaps, women working on the farm and the farmer reporting a problem with foxes.

Effects of environmental enrichment and loose housing of lactating sows on piglet performance before and after weaning

We investigated effects of loose housing of the sow during lactation and enrichment of the pen pre- and postweaning on performance of newly weaned piglets. Before weaning, piglets (n = 320) were housed in an enriched (straw, wood shavings, peat, and branches) or barren pen with a confined or loose-housed sow (n = 32). Loose-housed sows and their piglets could eat together from a family feeder, whereas confined sows and piglets had separate feeding troughs. Piglets (n = 256) were mixed postweaning, and 4 piglets from each litter were relocated to a barren pen (n = 32 pens) and 4 other piglets were housed in an enriched pen (n = 32 pens). Growth from d 15 until weaning was greater for piglets from enriched pens (4.38 ± 0.29 vs. 4.71 ± 0.21 kg/pig, P < 0.05) and tended to be greater for piglets with a loose-housed sow compared with piglets with a confined sow (4.41 ± 0.26 vs. 4.67 ± 0.24 kg/pig, P = 0.10). Preweaning feed intake was not affected by preweaning conditions (P > 0.25). Piglets from enriched preweaning pens ate more in the first 2 d postweaning than piglets from barren pens (first 48 h, barren 0.45 ± 0.05 kg/pig, enriched 0.53 ± 0.04 kg/pig, P < 0.05). Piglets relocated to an enriched pen after weaning showed a greater growth in the 2 wk after weaning (barren 5.5 ± 0.2 kg/pig, enriched 6.2 ± 0.2 kg/pig, P < 0.0001), had a profoundly reduced diarrhea prevalence than piglets housed in barren pens after weaning (barren 2.4 ± 0.4 d, enriched 1.0 ± 0.3 d, P < 0.0001), and had a greater feed efficiency (barren 0.81 ± 0.03, enriched 0.85 ± 0.02, P < 0.05). Enrichment of the preweaning environment likely stimulates development of feeding behaviors and consequently increases feed intake immediately after weaning. Providing piglets with an enriched environment after weaning positively affected postweaning growth, feed efficiency, and incidence of diarrhea, which may be caused by decreased stress or increased gut health. Enrichment of the pre- and postweaning environment seems important in improving performance and health of newly weaned pigs.

Heritability of post-mixing aggressiveness in grower-stage pigs and its relationship with production traits

Mixing of commercial pigs frequently leads to intense aggression. Considerable phenotypic variation exists between individuals and selection against aggressiveness may offer a long-term reduction in aggression without incurring additional costs to the primary producer. The genetic contribution to aggressiveness was quantified in this study using the number of skin lesions as an indicator of involvement in aggression. A sample of 1132 pigs were mixed at an average weight of 27·9 (s.d. 4·6) kg into 96 pens on a commercial sire line nucleus unit. Post-mixing aggressiveness of pigs was assessed using the lesion score (LS) approach. Growth rate, between 27·9 and 91·9 kg, and backfat depth at 91·9 kg were recorded for a subsample of 658 pigs. With a pedigree file of 1947 animals, a heritability of 0·22 was estimated for the LS trait. No significant genetic or phenotypic correlations were found between LS and growth rate or backfat depth, but standard errors of estimates were large. The response to selection, when all selection pressure was placed on the LS trait, was a 25% reduction in LS per generation. It is therefore technically possible to select for a reduced LS without substantially inhibiting genetic progress in growth rate or backfat depth through antagonistic genetic relationships.

Factors associated with preweaning mortality on commercial pig farms in England and Wales

Data from 67 pig farms with a variety of farrowing systems were used to identify factors associated with preweaning mortality in British pig herds. The median mortality reported by the farmers was 10.7 per cent (interquartile range 8.5 to 14 per cent). There was a significantly higher mortality when the pigs were weaned when they were older. A multivariable Poisson model was developed into which the types of farrowing system on each farm and the age at weaning were forced. Factors associated with a lower preweaning mortality rate were insulating the farrowing building, providing extra heat at farrowing, giving the piglets iron injections, dipping their navels, using fan ventilation and using artificial lighting systems. Factors associated with a higher mortality rate were a later weaning age, the use of infra-red lamps rather than other forms of supplementary heat, and the use of a creep without any bedding.

Foraging behaviour in domestic pigs (Sus scrofa): remembering and prioritizing food sites of different value

This experiment investigated whether domestic pigs can remember the locations of food sites of different relative value, and how a restricted retrieval choice affects their foraging behaviour. Nine juvenile female pigs were trained to relocate two food sites out of a possible eight in a spatial memory task. The two baited sites contained different amounts of food and an obstacle was added to the smaller amount to increase handling time. On each trial, a pig searched for the two baited sites (search visit). Once it had found and eaten the bait, it returned for a second (relocation) visit, in which the two same sites were baited. Baited sites were changed between trials. All subjects learnt the task. When allowed to retrieve both baits, the subjects showed no preference for retrieving a particular one first (experiment 1). When they were allowed to retrieve only one bait, a significant overall preference for retrieving the larger amount emerged across subjects (experiment 2). To test whether this preference reflected an avoidance of the obstacle with the smaller bait, 15 choice-restricted control trials were conducted. In control trials obstacles were present with both baits. Pigs continued to retrieve the larger bait, indicating they had discriminated between the two food sites on the basis of quantity or profitability and adjusted their behaviour accordingly when the relocation choice was restricted. This suggests for the first time that domestic pigs have the ability to discriminate between food sites of different relative value and to remember their respective locations.

A note on the effect of handling quality prior to mixing on behaviour at mixing in pigs

Previous research has raised the possibility that levels of aggression between pigs may be influenced by their state of arousal and excitement at the time of mixing. This may, in turn, be affected by factors such as the way in which pigs are handled prior to mixing. We attempted the first systematic test of this idea. Sixty four growing pigs were housed in groups of four for 4 weeks to allow them to become familiar with their group mates. Each pig was then tested in a 10min encounter with another pig in an unfamiliar test pen. Pigs were either handled gently (G) or firmly (F) on their way to the encounter. In addition, pigs either met a familiar (F) or an unfamiliar (U) pig in the test pen. Thus, there were four types of encounter (FF, FG, UF, UG) with N=8 tests of each. Two-way analysis of variance showed no effects of handling quality and no interactions between handling quality and familiarity on behaviour during encounters. Unfamiliar pigs showed higher levels of aggressive behaviour. Any fights were stopped immediately. On a second test day, pigs were handled as previously, but all now encountered a familiar individual. Again, there were no effects of handling quality or interactions between handling quality and familiarity. The results, thus, failed to support the idea that the quality of handling prior to mixing influences the levels of aggression subsequently observed.

Pigs shift too: foraging strategies and spatial memory in the domestic pig

In a previous experiment, we showed that domestic pigs, Sus scrofa, unlike many other species, performed accurately in a spatial memory task, where visits to a previously baited food trough were rewarded (win-stay). We investigated whether pigs have a predisposition for this strategy, by comparing their performance in a radial arm maze under either win-stay (N=10) or win-shift (N=10) reward contingencies. Contrary to our earlier results, only one of the animals in the win-stay condition was able to reach the imposed criterion level of accuracy. The performances of the other win-stay pigs did not deviate from random. All pigs in the win-shift condition reached criterion by day 25 of the experiment, and performed better than expected by chance. Analysis of the types of errors made matched our a priori predictions that shift movements would occur more frequently, especially within visits to the maze. We suggest that the difference in learning rates may reflect the fact that win-stay pigs needed to use two different rules, stay between trials and shift within trials, while win-shift pigs only needed to use the shift rule. In our previous study, win-stay pigs did not experience a conflict of rules and this may have facilitated stay learning. We found evidence of a recency effect in win-shift animals and a primacy effect in the win-stay group. However, we discuss the unsuitability of these specific terms in this type of experiment, and propose an alternative interpretation of the results. Copyright 2000 The Association for the Study of Animal Behaviour.

Social tactics of pigs in a competitive foraging task: the 'informed forager' paradigm

Studies of the social dynamics in foraging groups have focused primarily on birds, rodents and nonhuman primates. We extended the study of animal social tactics to the domestic pig, Sus scrofa, by using an experimental analogue of natural foraging skills, the 'informed forager' paradigm. We investigated the behaviour of 16 pigs foraging in pairs in an arena in which food had been hidden in one of eight monopolizable buckets. Before each pair trial, one of the pigs, the 'informed' pig, was given privileged knowledge about the location of the food during a solitary search trial. The 'noninformed' pig was naïve about the location of the food during pair trials, but heavier than its informed partner and thus able to displace the latter from the baited bucket. By first focusing on the informed pigs' behaviour, we show that pigs are able to remember and relocate the food site. They found the food in relocation trials, using fewer bucket investigations than expected of a random searcher. Second, by focusing on the noninformed pigs, we show that pigs are able to exploit the knowledge of others by following them to a food source. They investigated more buckets immediately after their informed partners significantly more often than expected by chance and required fewer bucket investigations to find the food in pair trials than expected from a random searcher, but not in solitary search trials. We discuss these latter findings with reference to social foraging tactics. Copyright 2000 The Association for the Study of Animal Behaviour.

The effects of environmental context on laboratory rat social recognition

Moving an animal from the environmental context in which it has learned a particular task to an entirely different context can reduce performance. We investigated the effect of switching environmental contexts on the ability of adult laboratory rats, Rattus norvegicus, to recognize and habituate to repeated presentations of juvenile conspecifics. Adults were exposed to juveniles for four periods of 5 min, separated by a 15-min interval. Rats either received all four exposures in the same context, or the first three in one context and the fourth in a different context. Half the rats in this latter group were familiarized with both contexts prior to testing, the other half had no experience of either. In all groups, the adults reduced their investigation of the juveniles over the three initial exposures. Mild aggression increased over the same period for the context-unfamiliar rats. A significant reduction in investigation by these rats between the third and fourth exposures, when the context was changed, suggested that the context switch further increased habituation to the juveniles. However, the context-familiar rats showed no such change, indicating that the changes observed for the context-unfamiliar rats were due to the effect of context novelty. This was supported by the finding that, during the first exposure, context-familiar adults investigated juveniles more and were more aggressive than those for which the contexts were novel. These results suggest that familiar contextual cues play only a minor role in the short-term social memory of laboratory rats. Copyright 1999 The Association for the Study of Animal Behaviour.

Multiple mechanisms may affect birth sex ratio in domestic pigs

No abstract. Copyright 1998 The Association for the Study of Animal Behaviour.

Pigs in space: spatial memory and its susceptibility to interference

This study provided basic information about spatial memory in the domestic pig, Sus scrofa and examined how susceptible it is to disruption by environmental stimuli. Eight male pigs were tested individually in a foraging arena. Each day, they entered the arena to search for food randomly located in one of 10 enclosed areas (search trial). After finding and eating the food, they were removed from the arena for a retention interval, and then allowed back in to relocate the food in the same area as previously (relocation trial). Once pigs had achieved a criterion level of performance in relocation trials, 'disturbances' (e.g. isolation, novel food source, novel spatial environment) were presented during the retention interval. Disturbance days were separated by control days on which no disturbance was presented. During search trials, pigs did not use food-related cues to locate food, but appeared to use memory to search systematically and avoid revisits to empty areas. During relocation trials, they found food using fewer area visits than expected by chance, indicating that they could remember the location of food across both 10-min and 2-h retention intervals. Disturbances administered during 10-min retention intervals resulted in more relocation errors than on corresponding control days, indicating that spatial memory in pigs is susceptible to interference by relatively mild environmental stimuli, in contrast to that in rats, Rattus norvegicus and pigeons, Columba livia which appears to be highly resistant to retroactive interference even when potent stimuli are used. Analysis of error locations suggested that disturbances probably acted to increase the general area in which the pig remembered the food to be located, and so reduced accuracy of memory without eradicating it. There was no evidence that errors made during relocation trials represented sampling of areas not visited during the preceding search trial.Copyright 1997 The Association for the Study of Animal Behaviour