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The purpose of this study was to determine how co-mingling litters affected piglets’ pre-weaning growth, ear injuries, suckling behaviour and responses to behavioural tests used to measure coping abilities. Thirty sows and their respective litters were housed in standard farrowing crates until day 13 after birth. On day13, the partition between two neighbouring pens was removed for 20 litters allowing piglets to interact (forming 10 co-mingled litters). The remaining 10 control litters were kept in standard farrowing crates throughout the experiment. Three focal piglets from each litter were used for data collection. Focal piglets were weighed and ear injuries recorded on days 2, 4, 9, 12, 15 and 18 after birth. There were no differences in piglets’ weight gain before or after co-mingling. Ear injuries were more abundant in co-mingled litters on day 15 ( P P P P P P

Animal evaluation courses have been part of animal science curricula for over 80 years in the US. A need for skills in the visual evaluation of conformation traits and the appraisal of productivity potential laid the foundation for animal judging courses. Eventually, these courses developed into competitions for students to compare their skill level. Following a similar framework, we propose that developing teams to educate young people about animal welfare, then establishing competitions to assess these skills will be a successful way to integrate animal welfare science into the mainstream of animal science curricula. Using traditional judging programs as a model, a paradigm for establishing animal welfare judging/assessment teams has been developed. Students take a background course in understanding evolutionary biology, biological needs, behavioral and physiological indicators of differing levels of welfare, and how to holistically evaluate facilities, stockmanship and management schemes. It should be noted that while the assessment of various aspects of animal welfare can be objective and quantifiable, judgment decisions of which area will be acceptable in the continuum between very poor and very good welfare still comes down to an ethics-based choice. Animal welfare assessment will teach students to integrate science-based knowledge with ethical values for an interdisciplinary approach to problem solving. The competition unfolds as follows: CD-ROM scenarios are prepared with indicators of animal welfare ranging from physiological data, video and still clips, to behavioral responses and time budgets. Students evaluate competition scenarios for each species being judged, prepare their analysis, then make an oral presentation of why they assess one scenario as demonstrating a higher level of welfare than another. The knowledge of welfare science in making the assessment, as well as the persuasion in the presentation, are key factors in scoring the students. A pilot competition was held March 1, 2002, at Michigan State University. Eighteen student participants from the University of Wisconsin, University of Guelph, Purdue University and Michigan State University competed in this pilot endeavor. Post-contest surveys demonstrated that 100% of the students felt the development of animal welfare judging teams was a good idea and that they would recommend the course to fellow students.

Our objective was to study dairy cattle’s preferences for handling practices by allowing animals to choose treatments in a Y-maze. Animals were first trained to expect one treatment on one side of the maze and another treatment on the other side of the maze. Animals were then allowed to choose between the two sides. In all experiments treatments were balanced for arm of the maze, color of clothing and handler. In the first experiment we validated the use of the Y-maze, using 34 heifers who chose between (a) pail feeding versus control; (b) hit/shout versus control and (c) hit/shout versus pail feeding. Heifers chose (a) pail feeding more often than control (P

We studied how “sow-controlled” housing (i.e. housing where sows can leave their piglets at will) affects the behaviour and performance of sows and litters when tested under near-commercial conditions and with two different levels of piglet diet quality. Sows and litters were housed in pens where sows had access to a piglet-free area (“sow-controlled”, n=28) or did not have such access (“confined”, n=26). Half of the litters in each treatment had access to a standard diet offered as creep feed from day 7, and the other half had a more complex diet that was richer in protein and fat. Piglets with access to the more complex diet consumed 50% more solid food before weaning than piglets provided the standard creep feed, and continued to eat more after weaning (days 29–49). The complex diet did not affect piglet body weight at weaning or at the end of the experiment, but did result in 52% greater weight gain during the first week after weaning. There were no other effects of diet or diet by housing interactions. Sows in the confined pens nursed their piglets 10% more often than did those in the sow-controlled pens and consumed 18% more food during lactation (i.e. until day 28). Before weaning, piglets in sow-controlled housing ate 65% more solid food than those in the confined pens, but the confined piglets weighed 11% more at weaning (day 28). With their greater intake of solid food before weaning, piglets in sow-controlled housing lost less weight on day 29 than did piglets from confined litters, but they still weighed less at the end of the experiment (14.5±0.4 kg versus 15.8±0.4 kg). Of the sows in the sow-controlled housing, those that spent the most time away nursed their piglets less often, consumed less food, and lost less weight over lactation; piglets of these sows consumed more creep feed before weaning, lost less weight on the day of weaning and gained more weight during the following week. Thus, both high-complexity creep feed and sow-controlled housing led to small improvements in piglet performance at weaning, as long as the mother spent considerable time away from the piglets. The sow-controlled housing may also provide advantages to the sows, especially in terms of reducing the demands of lactation.

Fear of humans is a source of stress for Holstein dairy cattle and can result when animals are handled aversively. We used aversion learning techniques to determine which handling practices cattle find most aversive. In an aversion race, the cows are repeatedly walked down a race and treatments applied when they reached the end; the time and force required for cows to walk down the race are measured. The animal learns to associate walking down the race with the treatment received; if the treatment is aversive, the animal will take more time and require more force to reach the end of the race than if the treatment is positive. In experiment 1, 54 cows were assigned to four treatments (hit/shout, brushing, control, and food). Treatments of 2-min duration were applied three times a day for 4 days. Cows on the hit/shout treatment took more time and required more force to walk through the race than cows on other treatments, while brushed cows took longer to move through the race than cows given food. In experiment 2, 60 cows were assigned to five treatments (electric prod, shouting, hitting, tail twist, and control). Treatments of 1-min duration were applied three times a day for 3 days. Cows on the shout and electric prod treatments took more time and required more force to walk down the race than cows on the control treatment. In experiment 3, thirty-six 1-1.5-year-old heifers were assigned to three treatments (hand feeding, gentling, or control) applied as in experiment 2. Treatments did not affect the time or force required to walk down the race. The aversion race successfully discriminated between handling treatments that differ greatly in aversiveness but lacked sensitivity to distinguish between treatments that were similar. Although many procedural factors must be considered, aversion learning techniques are an effective method to determine which handling practices cattle find aversive or rewarding.

We conducted an experiment to determine how allowing piglets access to a communal area affects pre-weaning and post-weaning behaviour and performance. Litters were housed in pens with sows in crates until piglets reached 11 days of age. For 10 experimental cohorts, barriers between the pens of three litters were removed allowing piglets to mingle freely in a central area. For the 10 control cohorts (also three litters each), litters were not allowed to mix before weaning. There was little aggression when experimental litters were allowed to mix, and piglets played and rested in mixed-litter groups. Time spent in the common area increased from approximately 20% just after mixing (12 days old) to approximately 45% at day 26 (week 4; P

We examined whether a sow-controlled housing system would ameliorate production and welfare problems resulting from the abrupt separation of piglets from sows at weaning. Forty-four sows and litters were housed during lactation in either a `confined' pen where the sow and litter were kept together, or a `get-away' pen where the sow could leave the litter by stepping over a barrier. Sows in get-away pens varied greatly in the amount of time they spent away from their piglets and were classified as `Early Leavers' if they spent more than 60% of their time away by the third week of lactation or `Late Leavers' if they did not. Body weight changes and food consumption of piglets were measured for 2 weeks after separation from the sow at 5 weeks post-partum. As a possible indicator of stress at weaning, sows and litters were tested for spontaneous behaviour and response to the playback of calls upon separation. Overall, piglets from get-away pens gained 27% more weight and consumed 31% more food after weaning than piglets from confined pens. Piglets from Early Leaver sows showed a non-significant tendency to gain more weight and consume more solid food than piglets from Late Leaver sows. Pre-separation accommodation and sow classification (Early versus Late Leavers) had a limited effect on post-separation piglet behaviour. Piglets from get-away pens were more active and bit pen-mates more after separation than piglets from confined pens. This was primarily due to the behaviour of piglets from Early Leaver sows which were more active and had a non-significant tendency to bite more than piglets from Late Leaver sows. However, accommodation treatment and sow classification had no clear effect on other spontaneous activity, vocalizations, rooting, or belly-nosing behaviour. Piglets responded to the playback of sow calls by orienting and moving toward the speaker and `freezing', but there was no effect of accommodation type or sow classification on these behaviours. Sows in get-away pens responded to removal of piglets by crossing the barrier and vocalizing more frequently. Playback of piglet vocalizations induced more movement, vocalizations and approaches to the speaker. Overall, accommodation treatment did not result in significant differences in movements or vocalizations in the post-separation period. However, Early Leavers moved and vocalized less frequently than Late Leavers. Thus, sow-controlled housing improves piglet food consumption and weight gain after weaning, but there is only slight evidence of an effect on behavioural indicators of stress for either the piglets or sows.

Crushing of piglets by sows in farrowing pens was studied in a 2×2 experiment to evaluate the effect of different pen design features. Pens had either concrete or plastic-coated expanded metal flooring, and half of the pens were fitted with a horizontal bar 23 cm above the floor, bisecting the pen. The bar was intended to prevent the sow from rolling suddenly onto her side, a movement known to crush piglets in open pens. Ninety-eight litters were analyzed during the first 3 days after birth when most crushing occurs. Of the 927 viable, live-born piglets, 95 (10.2%) died during the study, and 75 of these deaths were due to crushing as indicated by post mortem analysis. A high incidence of crushing was associated with larger litter size at birth, lower average piglet weight gain in early lactation, and older (high parity number) sows; however, these variables were interrelated, with older sows tending to have larger litters with lower early weight gains. Pens with a bar had significantly less crushing during the last 2 days of the study (Days 2–3), but this was fully offset by a non-significant tendency for more crushing in these pens on Days 0–1. Video recordings were analyzed for 16 sows with multiple crushings. Of eight types of sow body movement recorded, two caused most of the crushing: lying down from a standing position (54% of crushings observed), and rolling from lying on the udder to lying on the side (33% of crushings observed). Pen design features influenced how often the different movements were performed and how often these movements crushed piglets, but pen design did not affect the total number of movements or the total number of piglets crushed. Although the comparisons in the study did not result in significant differences in the incidence of crushing, the method shows promise as a way to identify design features that reduce the incidence of dangerous movements.

Crushing by the sow is a major cause of death for piglets. The behavior of 20 sows and their litters kept in two types of farrowing accommodation (farrowing crates and more open pens) was video recorded for 4 days after farrowing. In total, 24 piglets were killed by maternal crushing during the study (four in the farrowing crates, 20 in the pens). On 98 other occasions (30 in the farrowing crates, 68 in the pens) piglets were trapped beneath the sow but survived this ‘near-crushing’. Eight categories of sow body movements were recorded, including five types of transition between lying, sitting and standing, and three types of rolling movements. The frequency of these different movements varied between the two types of farrowing accommodation: for example, transitions from lying to sitting and from sitting to lying were more common in crates than pens (1.92 vs. 0.92 movements per sow per h), and rolls from the side to the udder and from the udder to the side were more frequent in the pens than crates (1.03 vs. 0.75 movements per sow per h). The rolling movements crushed piglets in pens (10 crushings) but not in crates, and the transitions between lying and sitting crushed piglets in crates (three crushings) but not in pens. The speed of rolling movements differed between the two types of farrowing accommodation. Rolling movements from the udder to the side required on average 12 s in pens vs. 20 s in crates. In both types of accommodation, more crushing occurred on the day of farrowing (0.05 crushings per sow per h) than during subsequent days (0.01 crushings per sow per h), and more while farrowing was in progress (0.11 crushings per sow per h) than during the rest of the day of farrowing (0.03 crushings per sow per h). The probability of a piglet dying was strongly related to the amount of time it was trapped under the sow. Of 84 piglets trapped less than 1 min only four were killed, whereas 16 died of the 24 that were trapped for more than 4 min. These results indicate that piglets are crushed by several different body movements whose relative importance depends on the design of the farrowing environment.

The pig provides many examples of how principles of behavioural ecology and sociobiology can lead to insights into farm animal behaviour. According to parent-offspring conflict theory, parents should tend to give a level of parental investment somewhat below that solicited by the young. When closely confined during lactation, sows can do little to limit the amount of contact with the piglets, and the young stimulate a prolonged, high level of lactation. Certain alternative housing systems allow the sow to limit the stimulation she receives, and the resulting reduction in lactation can actually be advantageous to both parties. Communal care of offspring has both advantages and disadvantages in various species; these may help to explain why communal care occurs to a limited extent in pigs, and why sows isolate their litters in early lactation. Neonatal competition and mortality among newborn piglets have strong parallels in the “facultative siblicide” which adjusts brood size in numerous species of birds. These species typically produce slightly more young than are normally raised, and the number of siblings that survive is determined by the ability of the smaller young to withstand intense competition. The hypothesis that pigs have evolved a similar system of brood reduction may explain why piglet mortality is such an enduring problem and requires solutions different from those that work for other domestic species. Resource defence theory provides a functional framework for studies of aggressive behaviour. Factors determining the defensibility of a resource include its degree of clumping in time and space, and these suggest ways to reduce competition for food and other resources. However, aggression involved in establishing social dominance is more likely to be influenced by manipulating traits of the competing animals (competitive ability, familiarity) rather than the defensibility of resources. We conclude that principles of behavioural ecology and sociobiology provide a useful functional and evolutionary perspective to complement other approaches to the study of farm animal behaviour.

Individual daily consumption of supplementary solid food (‘creep feed’) was measured from Day 10 to weaning at Day 28 for 39 piglets in four litters, and its relationship to body weight and weight gain up to Day 42 was investigated. Individual consumption was measured by combining the weight of the feed removed from the dispensers (monitored electronically) and a video image of piglet activity at the feeder. Creep feed consumption varied greatly, both between and within litters. On average, pigs began feeding on Day 12 (range Day 10–28), intake was relatively low (usually

Under normal farming practices, piglets from different litters are often mixed around the time of weaning, and a high incidence of fighting and minor injuries often occur. The aim of this experiment was to determine the effect of age on the incidence of fighting in piglets mixed before weaning, at different ages between 5 and 26 days. We found no significant relationship between age and the likelihood that a pair of piglets would fight during the first 75 min after mixing. However, the duration of the first fight observed increased from 101±38 s at 5 days to 621±278 s at 26 days, mainly because of higher levels of unretaliated harassment and resting during the bouts. Younger pigs also showed 80% fewer injuries from the fighting. The results suggest some potential welfare advantage to allowing litters to mix at younger ages.

We tested the hypothesis that sows and piglets are in conflict over parental investment. We assigned 41 multiparous sows to pens confined with their litters (C-sows, n = 17) or pens where they could leave the litter at will (get-away pens, n = 24). Sows in get-away pens were divided into those that spent more than 50% of their time away from piglets (leavers, L-sows, n = 15)) and those that spent less (behaviourally confined, BC-sows, n =9). L-sows nursed less frequently, had a shorter premassage and milk ejection, lost less weight, and returned to oestrus sooner than Cor BC-sows. Compared with piglets of Cand BC-sows, piglets of L-sows ate more creep feed, vocalised to their absent mother, had a higher rate of contact when the sow was present, and did not, lose weight on the day after weaning. With increasing litter age, L-sows terminated a higher proportion of nursings while Cand BC-sows spent a higher proportion of time lying on the udder. These results support the hypothesis that sows and litters are in conflict over the amount of milk provided and that piglets and sows can bias parental investment toward their own optimum.