Marek Å pinka

Abstract: For groups of animals to keep together, the group members have to perform switches between staying in one place and moving to another place in synchrony. However, synchronization imposes a cost on individual animals, because they have to switch from one to the other behaviour at a communal time rather than at their ideal times. Here we model this situation analytically for groups in which the ideal times vary quasinormally and grouping benefit increases linearly with group size. Across the parameter space consisting of variation in the grouping benefit/cost ratio and variation in how costly it is to act too early and too late, the most common optimal solutions are full synchronization with the group staying together and zero synchronization with immediate dissolution of the group, if the group is too small for the given benefit/cost ratio. Partial synchronization, with animals at the tails of the distribution switching individually and the central core of the group in synchrony, occurs only at a narrow stripe of the space. Synchronization cost never causes splitting of the group into two as either zero, partial or full synchronization is always more advantageous. Stable solutions dictate lower degree of synchrony and lower net benefits than optimal solutions for a large range of the parameter values. If groups undergo repeated synchronization challenges, they stay together or quickly dissolve, unless the animals assort themselves into a smaller group with less variation in the ideal times. We conclude with arguing that synchronization cost is different from other types of grouping costs since it does not increase much with increasing group size. As a result, larger groups may be more stable than smaller groups. This results in the paradoxical prediction that when the grouping benefit/grouping cost ratio increases, the average group sizes might decrease, since smaller groups will be able to withstand synchronization challenges.

Abstract: Interspecific communication between humans and pets is possible through vocal cues. We studied how humans with differing experience with domestic pigs (Sus scrofa) interpret pig vocalizations. Forty-eight ethologists studying pigs, 31 pig-caretakers and 54 naive students evaluated the emotional intensity and valence (negative/positive) of recordings from two negative (castration, isolation) and two positive (reunion with the sow, postsuckling) contexts. They also identified the context in which the recordings were made. Castration vocalizations were evaluated as highly intense and unpleasant. The positive contexts were evaluated as low in intensity and positive in valence, and isolation fell in the middle for both intensity and valence. Compared with the other two groups, pig-caretakers evaluated the intensity of vocalizations as lower, and ethologists evaluated the valence as more negative. The level of successful classification exceeded that expected by chance for all four contexts but was especially accurate for castration. Ethologists achieved better recognition than students. Classifying (right context) and understanding the emotional content (valence, intensity) of pig vocalizations is thus a general ability of humans, although it varies according to an individual's experience with pigs.

Abstract: Play behavior has been viewed as a mixture of elements drawn from "serious" behavior, interspersed by ritualized play signals. Two other types of play behaviors have been overlooked: patterns that are dissimilar from any serious behavior and patterns with self-handicapping character, that is, those that put the animal into unnecessary disadvantageous positions or situations. Here the authors show that these 2 types of patterns can constitute a major part of play repertoire. From our own videorecordings and observations, we constructed play ethograms of 5 monkey species (Semnopithecus entellus, Erythrocebus patas, Chlorocebus pygerythrus, Cercopithecus neglectus, and Cercopithecus diana). The authors evaluated the self-handicapping character of each pattern and in Hanuman langurs also the (dis)similarity to serious behavior. Of the 74 patterns in the 5 species, 33 (45%) were judged to have a self-handicapping character. Of 48 patterns observed in langurs, 16 (33%) were totally dissimilar to any serious langur behavior known to us. The authors discuss the possibility that the different types of play elements may have different functions in play.

Abstract: We evaluated how the behavioural and heart rate response of dairy cows and calves to mutual separation was affected by two factors: the age of the calf at separation (1, 4 and 7 days) and the presence or absence of visual and auditory contact between the mother and her calf after separation. In total, 46 cow–calf pairs were randomly allocated to one of six treatments according to a 3 × 2 factorial design. The cows’ behavioural response to separation was recorded at 0–1, 9–10, 25–26 and 50 and 51 h after separation. The calves’ behavioural response was recorded during the 24 h after separation. The heart rate was measured 60 min before and 60 min after separation. Cows from the later separation treatments spent more time standing (p < 0.01), placed their heads outside the pen (p < 0.001), vocalised (p < 0.05) and sniffed both the air (p < 0.01) and other animals (p < 0.001) more frequently compared to cows separated from their calves on day 1. The behavioural response was also more intense when the cows could see and hear their calves: they placed their heads outside the pen (p < 0.001), vocalised (p < 0.001) and sniffed the air (p < 0.01) more often than the no contact cows. Heart rate increased in all cows immediately after separation and was not influenced by the calf's age or by contact with the calf. After separation, older calves stood and moved more (p < 0.001), placed their heads outside the pen more often (p < 0.01) and showed more explorative behaviour (i.e. sniffing walls and bedding, p < 0.01; licking walls, p < 0.05) than the calves separated on day 1. Furthermore, the calves with visual and auditory contact with their mothers tended to place their heads outside the pen more often (p < 0.1) than the calves from the no contact treatments. Heart rate increased rapidly in all calves after separation; however, the increase lasted longer in the later separated calves (p < 0.05). At 3 weeks of age, the calves separated on day 7 habituated more quickly to the novel situation (p < 0.001). Calves separated on day 4 were more likely to engage in social play than the calves separated on days 1 and 7 (p < 0.05) and the calves denied post-separation contact with their dams also showed more social play compared to calves without this contact (p < 0.05). The results indicate that the response of cows and calves to separation is more intense and lasts longer when separation is delayed and that this effect is prolonged and further intensified when they are allowed visual and auditory contact after separation. On the other hand, delayed separation influences later social behaviour of calves in a way that may enhance their coping abilities.

Abstract: Although head rotations are frequent patterns in play behavior in many mammalian species and differ from head movements used in other contexts, they have not been quantitatively described and their function remains unclear. The head rotations occurring in the play behavior of free-ranging Hanuman langurs (Semnopithecus entellus) were described from videotaped sequences. The authors tested 2 possible hypotheses about their function. Either the head rotations serve to create unexpected situations and should therefore occur in both solitary and social play and also be very variable, or they serve as play signals and should therefore occur only in social play and be ritualized. If head rotations have both functions, they should be less variable in social play. The data revealed that head rotations were very variable and were present both in solitary and social play. Furthermore, there was no difference in the variability between the head rotations present in the 2 types of play. The results do not support the function of head rotations as play signals but, rather, suggest that head rotations may serve to create unexpected situations in play.

Abstract: The effect of the pre-weaning housing system on play behaviour before weaning and agonistic behaviour after weaning and during the fattening period was investigated in 32 litters of domestic pigs. Three preweaning housing systems were compared: poor crate (standard farrowing crate without straw), enriched crate (crate with straw, 20% larger), and, as a control, a farrowing pen (pen with straw, 60% larger than the poor crate). At the age of 1, 2 and 4 weeks, play behaviour (locomotor and social play) was recorded for 3 h. Four weeks post-partum, piglets were weaned and two litters from the same housing system were mixed in a new pen, with the stocking density corresponding to density in the pre-weaning poor crate. During mixing, the frequency of agonistic behaviour and the proportion of abnormally ended fights (chasing and biting to the hindquarters of the opponent) were recorded for 3 h, and after 6 h, the number of wounds was counted. Four focal pigs from each litter were chosen (two female and two male) and their agonistic interactions were measured during a food competition test at the age of 3 and 6 months. The pre-weaning housing system tended to have an effect on the frequency of locomotor (GLMM, p < 0.1) and social play (GLMM, p < 0.1) with piglets from the more enriched environments playing more frequently. The pre-weaning housing system did not affect the frequency of agonistic behaviour (GLMM, ns), the number of wounds after mixing (GLMM, ns) or the proportion of abnormally ended fights (GLMM, ns). During the food competition tests at 3 and 6 months pigs reared in the enriched pens were much less aggressive than the pigs reared in both types of crates (GLMM, p < 0.01). Our results suggest that the enrichment of the pre-weaning environment through straw and enlarged space probably stimulate pre-weaning play behaviour and substantially reduces the tendency of pigs to behave aggressively during food competition later in life. However, aggression during post-weaning mixing of piglets does not seem to be affected by pre-weaning enrichment. (c) 2006 Elsevier B.V. All fights reserved.

Abstract: The aims of the study were to identify the strategies used by allosucklers and teat losers during teat acquisition; to assess how teat fidelity was affected by allosuckling and how allosuckling affected weight gain of the allosuckler and teat loser. Ten pairs of sows and their litters were used in this study. For each pair, the two sows were housed individually until their litters were weaned; however, their litters had access to both sows from day 10 post-partum. The behaviour of the animals was videotaped for 6 h on days 10, 11, 16 and 24 post-partum. The strategy of teat acquisition and the teat fidelity were analysed for every pair and for every day of observation. All piglets were weighed on the day of birth, days 10 and 24 post-partum. The predominant takeover strategy (69%) was to occupy a teat from a piglet owning two teats. The other takeover strategy was to usurp a teat from a piglet owning one teat. In almost all cases (95%) teat losers were able to find a new teat in that nursing before milk ejection. The occurrence of allosuckling had no significant effect on the teat fidelity of the non-dam sow's litter (GLMM, NS). Permanent allosucklers did not differ in weight gain (Student's t-test, NS) from faithful piglets and the teat losers did not differ in weight gain from their littermates (Student's t-test, NS) on day 24 post-partum before weaning. Our results indicate that allosuckling does not confer any major advantage for allosuckling piglets but it does not impair the growth of the non-dam sow's litter.

Abstract: It has been suggested that fluctuating asymmetry (FA) reflects an animal's ability to cope with the sum of challenges during its growing period and, thus, is a potential welfare indicator. In this review we investigate the evidence of associations between FA and other welfare indicators measured at the level of the individual and of effects of welfare-relevant environmental conditions on FA in populations of captive birds and mammals including humans. As the question of validity cannot be treated independently from the quality of the available data, first a checklist for the proper measurement and analysis of FA is drafted and used to evaluate the methodological quality of the various studies. We recommend this checklist to be used as a standard for future FA studies. We found 17 relevant studies on associations between FA and other welfare indicators, and 36 studies on effects of welfare-relevant factors on FA. Frequent methodological shortcomings or insufficient methodological information allow for only cautious conclusions. The proportion of significant results supporting the link between higher FA and poorer welfare is only moderately high. Independent from statistical significance, almost all studies found the relationship between FA and welfare to be prevailingly in the expected direction. FA is a promising measure of animal welfare, despite a great number of open questions, e.g. relating to the ontogeny of FA or its sensitivity to various stressors. The considerable potential of FA as a welfare indicator makes it worthwhile to pursue more intensely validation studies as well as applied studies. These studies should pay particular attention to an appropriate methodological approach.

Abstract: The mechanisms of activity synchronization in group living ungulates are not well understood. In a case study on herd of 15 Gasconne beef cows with calves observed during a total of 25 summer daylight periods in 2004 and 2005, we examined whether cows similar to each other in body weight or in reproductive status were more synchronized and whether the timing of activity switches were determined by specific leading animals. We calculated the synchronization of all possible pairs of cows in the herd and tested the effects of similarity in body weight and in reproductive status (lactating vs. non-lactating) on synchronization in the pair. Further, we assessed whether any specific individuals, and especially the dominant cows, were more able, through their own activity switch, to incite another cow to follow shortly with her switch in activity. We found that body weight differences had a negative influence on pair synchronization (GLMM, F1,65 = 6.79; p < 0.05), but reproductive status did not affect the synchronization. Cows´ individual identity explained only a small proportion (< 2%) of variability in intervals between switches of subsequent cows. Furthermore, dominance status of an individual cow did not correlate with mean interval between her activity switches and activity switches of the next cow (lying down: rs = -0.16, n = 14, p > 0.10; standing up: Spearman correlation, rs = -0.38, n = 14, p > 0.10), indicating that there were no leading animals initiating switches in activity in our herd.

Abstract: Animals living in pairs often benefit from making behavioural switches synchronously. However, there is a trade-off between the need to synchronize and the need to stick to the individually different ideal time for the switch. We model this situation, assuming two mechanisms for achieving synchronization: either to be ready before the ideal individual moment, or to wait beyond it. The model identifies an optimal combination of readiness and waiting that brings the maximum benefit, in dependence on parameters including relative costs of nonsynchrony, acting too early, and acting too late. The model is examined in two variants, without or with communication between the animals about their preparedness to synchronize. For a majority of parameter values, the optimal strategy is to synchronize without communication (by just reacting to the other animal's action) and be ready before the ideal time, but not to wait. This strategy leads to premature switches in pairs compared to single animals. Communication only pays off when communicating is cheap and acting late is cheaper than acting prematurely. In this situation, communication is coupled with a pure waiting strategy and results in delayed switches. The model shows that synchronization is not symmetric in time which is a consequence of the inherent informational asymmetry of time.

Abstract: Begging behaviour by the young affects parental food distribution among nestlings of altricial birds. We present an analysis of two types of begging behaviour (assuming the front nest positions and gaping) based on videotaped natural nestling feeding in European common redstart (Phoenicurus phoenicurus). We test whether these types of begging support the predictions of two mathematical models: scramble competition with competitive asymmetries between nestlings [Anim. Behav.27 (1979) 1210] or honest signalling model [Nature352 (1991) 328]. None of the measured variables of nestling or parental behaviour were affected by body weight differences between siblings. In contrast, both gaping and nest positioning were affected by individual differences in nestling hunger. In agreement with the honest signalling model, hungrier nestlings gaped with higher probability and started to gape sooner after the arrival of the parent than did their less hungry nestmates. Those nestlings with the shortest latency to gape also received food more often. Nest positioning was related to nestling hunger in a way unforeseen by the existing models. The intervals between nestling position changes were several times longer than the intervals between parental feeding visits, and parents preferred to feed nestlings in front positions, so nestlings in front positions were always less hungry than nestlings in back. Hence the pattern of movements influenced the feeding decision in favour of the more satiated nestlings and acted against the effect of gaping. Nestling movement seemed to be caused by the less hungry nestlings moving actively from front to rear positions. Low mortality of individual nestlings within broods that survived to fledging and small within-brood variation in fledging weights indicated low competition among nestmates. We suggest that there are two behavioural mechanisms that contribute to the equalization of fledging weights in common redstart nestlings: the signalling of need through gaping and the regular turnover of nestlings at front positions.

Abstract: Twenty-four Czech dairy farms were visited to record lameness prevalence and to identify factors associated with high lameness prevalence at the farm level and/or increased lameness risk at the level of individual cows. All cows were checked for lameness and forty cows per farm were examined for overgrown claws, body dirtiness and skin lesions. The farm environment was scored between I (excellent) to 5 (very poor) in three different aspects: floor slipperiness, cow care quality, and housing quality. Data on hoof trimming schedules were obtained from farm managers. Lameness prevalence on farms was in a wide range from 6% to 42% (median 22%). At the farm level, floor slipperiness and poor animal care were associated with high lameness prevalence (Spearman correlations, P < 0.05), and the proportion of cows with overgrown claws tended to be associated with it (P < 0.10). The reported time schedules of hoof trimming (continuous trimming applied or not; and time elapsed since the whole herd was trimmed) were unrelated to either the prevalence of overgrown claws or the prevalence of lameness. Within farms, cows with overgrown claws and dirty cows were at an increased risk of being lame (multiple logistic regression, P < 0.05) and cows with skin lesions tended to be more lame (P < 0.10). The risk of lameness had an inverted U-shape dependence on age (P < 0.05), with cows at 7-8 years of age being the most endangered by lameness. We conclude that there is a large potential for lameness reduction on some Czech dairy farms through improving the cow care and reducing floor slipperiness, and that within farms, cows with overgrown claws and also dirty cows and cows with skin lesions should be given special attention since they are more likely to get lame.

Abstract: It is often assumed and demanded that for a good welfare, farm animals should be given "the freedom to express their natural behaviour". This demand is problematic for at least two reasons. First, natural behaviour is difficult to delineate because of its variability and flexibility. Second, some behavioural patterns that are clearly natural are in fact detrimental to animal welfare. These include emergency behaviours such as flight reactions that bring the animal into a state of stress without achieving the goal for which the behaviour had evolved; and damaging behaviours such as rank-related or illness-related aggression during which animals inflict injuries or deprive their penmates of resources. Nevertheless, when these reservations are taken into account, opening possibilities for natural behaviour may be useful as guidance for improving the existing husbandry systems. Specifically, providing the farm environment with the key features towards which the behaviour was originally adapted brings three classes of benefits. First, it is often more efficient to allow animals to satisfy their own needs and achieve their goals than to address these needs and goals through technical means. Second, a large class of natural behaviours is associated with positive affective experience, and thus their performance directly enhances animal welfare. Third, the performance of natural behaviour in its richness and complexity often brings long-term benefits for the animal, such as improved proficiency in coping with social and physical challenges. Thus, while the freedom to perform the whole repertoire of natural behaviour is not per se crucial for farm animal welfare, the opportunity to perform natural behaviour may be an effective way improve their welfare in practice immediately, and a promising basis for the design of husbandry systems for the future. (c) 2006 Elsevier B.V. All rights reserved.

Abstract: The sow nursing behaviour may be affected by housing environment. So far, studies have focused on within-farm experimental comparisons, but data comparing nursing behaviour in a sample of commercial farms using different housing systems are lacking. This study had the following goals: (I) To compare sow nursing behaviour in a sample of farms with group housing (GH) and individual housing (IN) systems for lactating sows with piglets. (II) To quantify the variability in nursing behaviour attributable to between-farm differences. (III) To document the decline in maternal nursing investment in GH and IH during the last 2 weeks before weaning. The observations were carried out in five GH (6-11 sows kept in a large pen) and in five IH (each sow kept in a small pen) commercial farms. Nursing behaviour of four focal sows per farm was recorded for 6 It in two lactation periods (fourth week, I day before weaning; weaning = 5.5 weeks on an average). There was no significant difference between GH and IH farms in total number of nursings, in number of nutritive nursings or in proportion of nursings initiated by the sows. However on GH farms sows terminated higher proportion of nursings (p = 0.05) and allowed piglets' post-ejection massage for shorter time (p = 0.02). Nursing synchronization was higher among sows on GH than on IH farms (p = 0.006). The proportion of variability attributable to the between-farm differences ranged between 6 and 30% for the individual nursing behaviour variables. The effect of lactation period was not significant for any of the variables suggesting that maternal investment was not declining between weeks 4 and 6 in either environment. (c) 2006 Elsevier B.V. All rights reserved.

Abstract: We collected questionnaires from 128 stockpersons on 31 Czech dairy farms with the aim to examine three questions: (i) whether the stockpersons' personality profiles, their attitudes and beliefs about cows, and their age/experience were related to farm performance indicators such as milk yield per standardised lactation, culling of cows or costs of veterinary treatments; (ii) whether stockpersons' personalities and attitudes were related to their age, gender and duration of their experience with cattle; and, (iii) how the personality traits of stockpersons differed from the same traits in the general Czech population. The NEO Big Five Personality Inventory questionnaires were used to describe the personalities of the stockpersons in five dimensions: neuroticism, extroversion, openness to experience, agreeableness and conscientiousness. The attitudes towards cows were examined using a custom-made questionnaire. Attitudes towards cows, as measured by our questionnaire, were unrelated to farm performance. Farms with more neurotic stockpersons had lower milk yields per standardised lactation (r(S) = -0.38, P < 0.05, n = 31) and higher veterinary costs (r(S) = 0.40, P < 0.05, n = 30) and farms with more conscientious staff had lower veterinary costs (r(S) = -0.37, P < 0.05, n = 30). Farms with older stockpersons had higher milk sale prices (r(S) = 0.53, P not greater than 0.01, n = 31) and lower veterinary expenses (r(S) = -0.43, P < 0.05, n = 30). On the level of individual stockpersons, longer history of working with dairy cattle was related to lower neuroticism (r(S) = -0.25, P < 0.01, n = 128). Female stockpersons were more neurotic (P < 0.05) and more agreeable (P < 0.01) than male stockpersons. Stockpersons were substantially less extroverted (P < 0.001), substantially less open to experience (P < 0.001), somewhat less agreeable (P < 0.05) and somewhat more conscientious (P < 0.05) than the average of the Czech population. In conclusion, this study suggests that stockpersons differ in their personalities from the general population and that their personality profiles (but not attitudes towards the animals) might affect dairy farm performance.

Abstract: Non-offspring nursing (allosuckling) is costly for lactating females. It is reasonable to assume, therefore, that mechanisms have evolved to control the frequency of allosuckling. It is suggested that the synchronization of nursing between females could be such a mechanism. The aim of this study was to investigate whether nursing synchronization is related to the timing of nursing behaviour of paired sows and the behaviour of alien piglets in relation to allosuckling. Specifically, we predicted that: (i) nursing synchronization will increase if there is a real risk of allosuckling compared with a situation where there is none, (ii) nursing synchronization indeed reduces allosuckling and, therefore, those nursings with allosuckling attempts will be less closely synchronized than those without allosuckling attempts and (iii) in non-synchronized nursings, the sows will more often employ another strategy to reduce allosuckling, namely, they will make the nursings non-nutritive by not releasing milk. Ten pairs of sows and their litters were used in this study. For each pair, the two sows were housed individually until their litters were weaned; however, their litters had access to both sows from day 11 post-partum. The behaviour of the 10 pairs of sows with their litters was videotaped for 6 h on days 10, 11, 17 and 24 post-partum. The frequency of allosuckling attempts, non-nutritive nursings and allosuckling during milk ejection was analysed for every pair for every day of observation. The observed frequency of nursing synchronization was high. The median interval between the start of a nursing within one pair of sows was 32 s. The first prediction was supported as synchronization became significantly tighter when piglets were given the possibility to allosuckle on day 11 [Cochran-Mantel-Haenszel (CMH) statistics, p < 0.0001]. The second prediction was also supported; the nursings were less closely synchronized when there were allosuckling attempts (CMH statistics, p < 0.05). Of all nursings, 36% had an allosuckling attempt; however, only 17% resulted in real allosuckling. Evidence in favour of the third prediction was also found as non-nutritive nursings were more frequent in non-synchronized nursings (CMH statistics, p < 0.05). Finally, real allosuckling during milk ejection was unrelated to the degree of nursing synchronization, as in less synchronized nursings, the sows responded to allosuckling attempts by not releasing milk. Our results suggest that sows are not able to completely suppress allosuckling; however, they can reduce its frequency through nursing synchronization and non-nutritive nursings.

Abstract: We analysed video-sequences of undisturbed parental provisioning behaviour on 12 nests of common redstart (Phoenicurus phoenicurus). In 4 of the 12 nests, chicks were fed by a single parent only. We compared provisioning rate of chicks, time spent on the nest and food allocation rules between nests with uniparental and biparental care and between male and female parents in biparental nests. In nests with a single parent, the frequency of feeding visits per parent was higher than in biparental nests. As a result, the rate of food provisioning of chicks was similar in uniparental and biparental nests. The food allocation rules did not differ between uniparental and biparental nests. In biparental nests, male and female provisioning behaviour was similar though with two exceptions: males had a strong preference for feeding chicks in front positions in the nest and females spent a longer time on the nest after feeding. We conclude that single common redstart parents are able to compensate fully for the absence of the other parent through increased provisioning efforts, and that in biparental nests, males and females contribute equally to the provisioning of the young.

Abstract: In this study, the amount of nursing synchronisation was quantified, the dependence of the degree of synchronisation on the spatial distance between sows was examined, and the effect of nursing vocalisation playback on nursing frequency and nursing synchronisation was assessed in a large commercial pig farm. Sows were housed in individual farrowing crates, 14 sows per room. Twelve rooms were assigned to one of four treatments in a 2 x 2 experimental design, with the factors being AGE of piglets (observations at either 6-10 days or at 13-17 days postpartum) and BASS frequencies on the loudspeakers being switched on or off. The third factor (PLAYBACK) was applied in a repeated measures design on the 3 days of observation in each room. Three-min playbacks of sow nursing sounds were played back every 45, or 55 min, or not at all, for a period of 24 h on the 3 days. The nursing behaviour and its synchronisation were recorded in two ways: through a 2 h direct interval sampling observations of all sows and through a 6 It video recording of three focal sows. The nursing synchronisation, measured in standardized degree of synchrony (SDS, i.e. proportion maximally possible synchronisation), was high at 0.53. This SDS in nursing was much higher than the SDS in activity which only reached 0.26. Synchronisation in pairs of sows declined with increasing distance. A significant quadratic effect in this relationship indicated that the decline was steepest when pairs of sows housed in neighbouring pens and pairs of sows one crate away were compared. The playback of nursing sounds did not increase either the nursing frequency or the nursing synchronisation. It is concluded that nursing synchronisation is high in large rooms with crated sows, that it is not a sole consequence of synchronisation in general activity, that it depends on the distance between the sows, and that an increase in nursing frequency is not always reliably induced by a playback of pig nursing vocalisations. (C) 2004 Elsevier B.V. All rights reserved.

Abstract: The aim of the present study was to investigate how oxytocin, prolactin and somatostatin during nursings relate to maternal characteristics of sows. Undisturbed nursing behaviour and sow-piglet nasal contacts of 21 lactating sows were recorded on day 13 of lactation, and hormonal status was assessed during three successful nursings on day 14. Piglet and litter growth (days 8-15), sow weight loss (days 1-15) and catabolic state (measured as NEFA on day 7), as well as number of successful nursings on day 13 were used as measures of mobilisation of sow body resources. Nasal contacts and sow behaviour facilitating udder massage were used as measures of positive piglet-directed behaviours. Concentrations of oxytocin were higher, those of prolactin lower and those of somatostatin similar during nursings compared to samples taken 15 min after nursing. Oxytocin peaked during most nursings and prolactin increased gradually after nursings. Non-nursing oxytocin values were positively correlated with the proportion of sow-terminated nursings but not with other measures of piglet-directed behaviour. Non-nursing oxytocin concentrations were positively correlated with piglet weight gain and concentrations of oxytocin during nursings were correlated with NEFA and sow weight loss. Our results indicate that oxytocin might have more than merely an all-or-nothing function in triggering milk ejection. Oxytocin seems to be quantitatively related to efficiency of milk production, although the present study design does not allow for speculation on causal relationships. (C) 2003 Elsevier B.V. All rights reserved.

Abstract: Starvation and crushing by the sow are the two main causes of piglet mortality prior to weaning, thus it is obvious that the behaviour of the sow influences piglet survival. In order to increase the understanding of the behavioural mechanisms influencing piglet performance, we recorded undisturbed general activity (standing or walking), frequency of standing-to-lying posture changes (standing-to-lying) and carefulness at standing-to-lying during a 5-week lactation for 24 Yorkshire sows. Carefulness was estimated using four components of sow anti-crushing behaviour (rooting or sniffing piglet prior to standing-to-lying, careful standing-to-lying and no piglets in danger zone at standing-to-lying). We investigated the changes in and consistency of these behaviours throughout lactation, as well as the associations between different aspects of behaviour. Secondly, we examined whether sow activity level and frequency of standing-to-lying were related to nursing behaviour, sow body resource mobilisation (measured as blood concentration of non-esterified fatty-acids (NEFA)) and piglet growth. In addition, we grouped the sows according to litter mortality and according to whether they had crushed any piglets or not and determined if these groups differed in the above mentioned behaviour patterns. Both the activity level and frequency of standing-to-lying of sows increased and had high within-sow repeatability throughout the 5-week period. Carefulness at standing-to-lying did not change significantly over lactation. The variable showed very low within-sow repeatability and only one aspect of carefulness (rooting of the floor) decreased in the later stages of lactation. No significant associations were found between activity level and frequency of standing-to-lying on the one hand, and nursing behaviour or growth of the piglets on the other, except for a positive correlation between frequency of standing-to-lying and observations of the sow lying on her udder. Sows with low mortality (less than two dead piglets) in their litters were more active on day 3 postpartum (pp) than sows with high mortality. The difference was especially clear when comparing sows with or without any crushed piglets in their litters. Sows with no crushed piglets also showed a higher incidence of rooting the floor on day 3 than sows with at least one crushed piglet. Activity level of the sow seems to be an individual characteristic that has possibly been decreased by selection for large and docile animals, suited to intensive production systems. Activity level and amount of rooting performed at standing-to-lying appear to be important aspects of good maternal characteristics. Our results encourage studies of selection for enhanced piglet survival via improved maternal abilities. (C) 2003 Elsevier Science B.V. All rights reserved.

Abstract: Twenty-one sows were studied to investigate if lactating sow metabolism relates to behaviour and piglet performance. Blood samples from days 7 and 21 were analysed for NEFA, urea, glucose, insulin, somatostatin and prolactin. The behaviour parameters obtained from 24-h video recordings (days 6 and 20) included: successful and unsuccessful nursing frequency, total nursing duration, percentage and average duration of nursings terminated by the sow, and percentage of observations of sow sternal recumbency. Weight loss and catabolic state of the sows increased from day 7 to day 21; NEFA and post-feeding urea were higher and pre-feeding glucose and insulin lower on day 21. NEFA correlated strongly with sow weight loss during week 1. Prolactin correlated positively with the amount of udder stimulation in week I and insulin positively (week 1) or negatively (week 3) with a high incidence of massage-avoiding behaviour. High sow weight loss and NEFA during week I were associated with low piglet mortality. High piglet growth correlated positively with sow weight loss during week 3. We conclude that (i) catabolism increases during the first 3 weeks of lactation, (ii) there is some association between sow metabolism and behaviour and (iii) the ability of a sow to turn catabolic soon after parturition decreases piglet mortality risk. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract: We present a model that simulates the evolution of teat massaging (begging) by suckling piglets (Sus scrofa) and milk distribution among teats (provisioning) by their mothers. Contrary to previous begging models, this one incorporates an ontogenetic dimension in that the inherited begging and provisioning rules are repeatedly allowed to interact, and their consequences for milk intake, growth and death probability are assessed, during each nursing. We test the model under three selection regimes differing in the relative importance of the between-litter selection component. We show that the selection regime with the strongest between-litter selection component leads to lowest begging levels and most effective milk utilization, thus supporting the hypothesis that selection based on whole litters may attenuate sibling competition.

Abstract: Parental recognition of offspring is important in highly social animals. Both wild and free-ranging domestic sows live in groups during lactation, except for a few days of isolation directly after parturition. It is therefore important that a sow is able to discriminate her own piglets from alien piglets both at close contact and from a distance. We investigated whether piglets' vocalizations at 10 days of age may serve this function. Vocalizations of own and alien piglets were recorded on day 9 postpartum whilst the piglets were isolated from the sow for 5 min (isolation calls, i-calls) and when piglets were returned to their sows afterwards (contact calls, c-calls). We first examined whether the two types of piglet vocalizations include cues which make it possible to discriminate between individual litters. A total of 2155 i-calls and 475 c-calls were sampled. From digitized calls, a total of 50 acoustic parameters were calculated and then subjected to a discriminant function analysis (forward stepwise method). Both i-calls and c-calls could be classified significantly better to the correct litters than would be expected by chance. In a playback experiment, whether sows isolated from their piglets respond more strongly to i-calls and c-calls of their own piglets than to alien calls was tested. For both the i-calls (N = 12 sows) and c-calls (N = 8 sows) sows responded with more vocalizations to the playback of own piglets' voices than to the playback of alien piglets' voices. The study shows that piglet calls contain acoustic cues that are litter typical and that sows are able to recognize their offspring based on these cues.

Abstract: We hypothesised that play experience gained by piglets during early ontogeny would affect their ability to cope with weaning stress. Specifically, we predicted that (i) weaning would initially result in low play levels and (ii) better coping ability would be reflected by a more rapid increase in play levels with time after weaning. We manipulated play experience in three pre-weaning treatments (1) Obstacles (play with littermates restricted by barriers throughout the 2.1 m x 1.8 m home pen and a 1.7 m x 1.5 m observation pen into which each litter was placed during seven 30 min periods between day 8 and day 23), (2) Littermates (unobstructed play with littermates in home pen, and observation pen), and (3) Aliens (unobstructed play with littermates in home pen, and with littermates and non-littermates in observation pen). We expected the treatments to increase coping ability as follows: Aliens > Littermates > Obstacles. Two males and two females from each of eight litters per treatment were housed together after weaning at day 24. On days 1, 3 and 5 after weaning, they were placed in the (unobstructed) observation pen for 30 min. Data were analysed using mixed model repeated measures analysis of variance on log-transformed data. In all three play categories studied (locomotor play: scampers, pivots, head tosses, flops and paws; social play: non-injurious bites, levers, and "push-overs"; and transitions to self-handicapping positions: sitting, kneeling or lying), the frequency of play behaviour was lower on day 1 after weaning than on the day before weaning, and increased to pre-weaning or higher levels on days 3 and 5 after weaning (P < 0.001). On day 3 after weaning, the frequency of social play behaviour was in the predicted direction (Aliens > Littermates > Obstacles) resulting in a significant treatment x time effect (P < 0.05). Our results indicate that the depression of play after weaning is profound but transient. We found evidence that early play experience before weaning had some effect on social play after weaning, but not on total locomotor play or transitions to self-handicapping postures in the first week after weaning. (C) 2002 Elsevier Science B.V. All rights reserved.

Abstract: We investigated whether domestic sow discriminates one day old piglets based on their individual odours or based on some odour common to the whole litter. We manipulated the contacts between sow and piglets during the first 24 h post partum in such a way that produced 4 types of piglets, as combinations of two factors: relatedness and familiarity. We used ten pairs of sows individually housed in farrowing pens in which parturitions were induced on the same day. When the manipulations were finished, each sow was subjected to two testing situations. First it was a 5 min choice test in which the sow could show her preference for the 4 types of anaesthetized (immobile and mute) piglets: Own Familiar, Own Unfamiliar, Alien Familiar and Alien Unfamiliar. Second the sow was subjected to three 2.5 min preference tests with the following combinations of dyads of awake piglets: Own Familiar vs Alien Unfamiliar; Own Familiar vs Own Unfamiliar; Alien Unfamiliar vs Alien Familiar. We recorded the frequency and duration of visits and the grunting rate of sow with respect to each piglet type, in the test with awake piglets we also recorded piglets' vocalisation and movement. In the test with anaesthetized piglets we found a significant effect of piglet type on the duration of visits (F(3,16) = 3.94, p = 0.014). The significant difference between Own Unfamiliar and Own Familiar piglets indicates that sows use the individual odours of piglets to discriminate between own and alien ones. The number of visits to individual piglets was also affected by piglet type (F(3,16) = 2.71, p = 0.055), with sows visiting Own Familiar piglets significantly more often than Alien Unfamiliar ones. In none of the three preference tests with awake piglets did the sows show significant preference for a specific type of piglet. However the sows' visits in the piglets was affected by the piglets' activity. In periods when both the piglets were moving the sow spent a greater proportion of time by visiting them (Students t-test, N = 11, mean = 0. 12, p = 0.00 14) then during periods when only one or none of the piglets was moving. Sows also spent a greater proportion of time visiting the piglets when they were vocalising (Students t-test, N = 11, mean = 0. 129, p = 0.019) than when they were not. The study shows that early recognition of piglets by sows is probably mediated by the individual odour of each piglet and that kinetic and acoustic cues augment the motivation to reunite with the piglets and this may then override the willingness to discriminate among them.

Abstract: We examined the repeatability of pig nursing behaviour and its relationship with maternal investment (measured in piglet growth) in two experiments. In Experiment 1, eleven sows were followed for 2-5 (median 3) lactations, and their nursing behaviour was recorded on Day 11 post partum during each of these lactations. In Experiment 2, fourteen sows were followed for two consecutive lactations, and their nursing behaviour recorded on Days 7 and 28. In Experiment 2, the data on piglet growth between Days 1 and 6, and between Days 6 and 28 were also recorded, and mortality data were available in both experiments. We evaluated the data in order to get answers to three basic questions: First, was the nursing behaviour repeatable within and across lactations, i.e. did the sow have individually stable nursing styles? Second, was the variability in nursing behaviour related to piglet growth or mortality? Third, were the sows inclined to nurse repeatedly on one side and if so, did this result in faster growth and/or lower mortality in the piglets suckling the 'upper row' teats? We found that the pattern of grunting vocalisation emitted by the sow was highly repeatable both within and across lactations. We hypothesise that this individual acoustic signal may be used by piglets to locate their mother during synchronised nursings in the group living female pigs. However, the variables characterising nursing frequency, the willingness of the sow to allow udder massage by the piglets, and the laterality of nursing had low or no repeatabilities within and across lactations. Piglet growth was only loosely, and piglet mortality not at all, related to the quantitative variability in nursing behaviour casting doubts on whether nursing behaviour variables are suitable for selection programs. Although some sows preferred to nurse while lying on the left, and others on the right side, this laterality did not result in faster growth of piglets suckling the upper row of teats.

Abstract: In an experiment investigating the impact of preweaning social experience on later social behavior in pigs, we were interested in the mutual spatial positions of pigs during paired social interactions. To obtain these data, we applied a different colored mark to the, head and back of each of 2 pigs per group and videotaped the pigs' interactions. We used the EthoVision tracking system to provide xy coordinates of the four colored marks every 0.2 sec. This paper describes the structure and functioning of a FoxPro, program designed to clean the raw data and use it to identify the mutual body positions of the 2 animals at 0.2-sec intervals. Cleaning the data was achieved by identifying invalid data points and replacing them by interpolations. An algorithm was then applied to extract three variables from the coordinates. (1) whether the two pigs were in body contact; (2) the mutual orientation (parallel, antiparallel, or perpendicular) of the twos pigs; and (3) whether the pig in the "active" position made snout contact in front of, or behind, the ear base of the other pig. Using these variables, we were able to identify five interaction, types: Pig A attacks, Pig B attacks, undecided head-to-head position, "clinch" resting position, or no contact. To assess the, reliability of the automatic system, a randomly chosen 5-min videotaped interaction was scored for mutual positions both visually (by 2 independent observers) and automatically. Good agreement was found between the data from the 2 observers and between each observers data and the data from the automated system, as assessed using Cohen's kappa coefficients.

Abstract: In some nursings, piglets initiate nose contacts with their mother and emit typical 'croaking' vocalizations. We examined whether the croaking vocalizations reflect the condition of the piglets and whether the sows increase their maternal investments in response to those vocalizations. The following predictions were tested: (i) Piglets with lower weight gain should Vocalize more than piglets with higher weight gain; (ii) piglets' milk intake is lower in those nursings in which they vocalize after milk ejection; (iii) piglets make more croaking vocalization in nursings which were preceded by longer intervals since the last nursing with milk ejection; (iv) sows permit longer post-ejection massage in nursings in which piglets vocalized immediately after milk ejection; (v) sows decrease the interval until the succeeding nursing after those nursings in which the piglets have vocalized. Hypotheses (i) and (ii) were investigated by controlling the inter-nursing intervals in 14 sows and recording the milk intake of individual piglets' over 24 hours during days 7 or 8 post partum (Experiment 1). Hypotheses (iii) to (v) were examined through analysing video recordings of undisturbed six h nursing sequences in 29 sows (Experiments 2 and 3). The majority of our predictions were not confirmed: piglets did not vocalize more (either before or after milk ejection) after longer intervals since last milk ejection; they did not vocalize more in nursing in which they received less milk; and it was not the piglets or the litter with a lower milk intake or lower weightgain that emitted more vocalization. Neither of our predictions regarding the influence of croaking vocalizations on maternal investment was confirmed. The vocalizations were in no way associated with the length of the following inter-nursing interval or with the permission of longer udder massage. To conclude, piglet croaking vocalizations during nursings are not reliable indicators of piglet condition and are not used by sows to adjust their maternal investment.

Abstract: Group housing systems for lactating sows with piglets enable the animals to behave more naturally than traditional restrictive systems. However, piglets may occasionally suckle from other sows than their mother. The influence of litter size, age of the litter, mother parity, piglet gender and, in particular, nursing synchronisation, on the following: the occurrence of cross-suckling (presence of alien piglets at the udder during milk ejection); cross-suckling strategies; and piglets' success at achieving nursings, was investigated. The observations were carried out on six stable groups of three or four unrelated sows with their piglets between 19 and 32 days postpartum. Cross-suckling was frequent (occurred in 29% of all suckling events). The main determinant of cross-suckling was litter size. Piglets from larger litters missed nursings of their mothers more often (r(s) = 0.72; n = 22; P < 0.001) and performed cross-suckling more often than piglets from smaller litters (r(s) = 0.54; n = 22; P < 0.05). Piglets, who were observed suckling only alien sows, belonged to larger litters than piglets suckling only their own mother (Wilcoxon signed rank T-test; n = 6; P < 0.05). Sows with larger litters were preferred targets for cross-suckling (Wilcoxon signed rank T-test; n = 78; P < 0.001). Piglets from older litters cross-suckled more often than piglets from younger litters (r(s) = 0.50; n = 22; P < 0.05). Nursing synchronisation (sows nursing within one minute of each other) was high at 82%. Sows nursing immediately after, other sows attracted less cross-suckling. The higher the number of sows which had nursed just before a focal sow, the fewer alien piglets were then present at her nursing (r(s) = -0.35; n = 14; Cochran-Mantel-Haenszel (CMH) statistic; P < 0.05). Piglets belonging to a specific litter were less likely to cross-suckle at an alien sow if her nursing was preceded by a nursing of the mother of that litter (CMH statistic for 28 piglets, P <less than> 0.01). Permanently cross-suckling, occasionally cross-suckling and faithful piglets achieved a similar number of suckling events indicating that these strategies may be equally successful in a stabilised multi-suckling situation. Mother parity and piglets' gender had no effect on cross-suckling. (C) 2001 Elsevier Science B.V. All rights reserved.

Abstract: In this review, we present a new conceptual framework for the study of play behavior, a hitherto puzzling array of seemingly purposeless and unrelated behavioral elements that are recognizable as play throughout the mammalian lineage. Our major new functional hypothesis is that play enables animals to develop flexible kinematic and emotional responses to unexpected events in which they experience a sudden loss of control. Specifically, we propose that play functions to increase the versatility of movements used to recover from sudden shocks such as loss of balance and falling over, and to enhance the ability of animals to cope emotionally with unexpected stressful situations. To obtain this "training for the unexpected," we suggest that animals actively seek and create unexpected situations in play through self-handicapping; that is, deliberately relaxing control over their movements or actively putting themselves into disadvantageous positions and situations. Thus, play is comprised of sequences in which the players switch rapidly between well-controlled movements similar to those used in "serious" behavior and self-handicapping movements that result in temporary loss of control. We propose that this playful switching between in-control and out-of-control elements is cognitively demanding, setting phylogenetic and ontogenetic constraints on play, and is underlain by neuroendocrinological responses that produce a complex emotional state known as "having fun." Furthermore, we propose that play is often prompted by relatively novel or unpredictable stimuli, and is thus related to, although distinct from, exploration. We present 24 predictions that arise from our new theoretical framework, examining the extent to which they are supported by the existing empirical evidence and contrasting them with the predictions of four major alternative hypotheses about play. We argue that our "training for the unexpected" hypothesis can account for some previously puzzling kinematic, structural, motivational, emotional, cognitive, social, ontogenetic, and phylogenetic aspects of play. It may also account for a diversity of individual methods for coping with unexpected misfortunes.

Abstract: In an experiment investigating the impact of preweaning social experience on later social behavior in pigs, we were interested in the mutual spatial positions of pigs during paired social interactions. To obtain these data, we applied a different colored mark to the head and back of each of 2 pigs per group and videotaped the pigs' interactions. We used the EthoVision tracking system to provide x,y coordinates of the four colored marks every 0.2 sec. This paper describes the structure and functioning of a FoxPro program designed to clean the raw data and use it to identify the mutual body positions of the 2 animals at 0.2-sec intervals. Cleaning the data was achieved by identifying invalid data points and replacing them by interpolations. An algorithm was then applied to extract three variables from the coordinates: (1) whether the two pigs were in body contact; (2) the mutual orientation (parallel, antiparallel, or perpendicular) of the two pigs; and (3) whether the pig in the "active" position made snout contact in front of, or behind, the ear base of the other pig. Using these variables, we were able to identify five interaction types: Pig A attacks, Pig B attacks, undecided head-to-head position, "clinch" resting position, or no contact. To assess the reliability of the automatic system, a randomly chosen 5-min videotaped interaction was scored for mutual positions both visually (by 2 independent observers) and automatically. Good agreement was found between the data from the 2 observers and between each observer's data and the data from the automated system, as assessed using Cohen's kappa coefficients.

Abstract: We examined the maternal behaviour of seven domestic and seven wilds domestic primiparous sows during 10 days post partum to investigate two questions: (1) Did maternal behaviour change during domestication? (2) Can the interindividual variability of maternal behaviour be subsumed into a few dimensions of maternal temperament? We recorded: (a) willingness to leave the nest for food on Day 2; (b) reaction to a playback of squeezed piglet distress vocalisation on Day 2; (c) spontaneous nursing behaviour and spontaneous lying-down behaviour on Day 5 (from an overnight video recording); (d) reactions to playbacks of various piglet distress vocalisations on Day 6 and (e) reactions to a human in the 'nest' with piglets on Day 9. Moreover, data on baseline cortisol saliva concentration and its increase during a brief transportation period and novel environment challenge at the age of 5 months were available. Crossbred sows did not differ from domestic ones in any aspect of maternal behaviour except for a higher tendency to terminate final massage during nursings and a higher frequency of changing posture from lying to standing and back during the night. Factor analysis (based on correlation matrix of 11 behaviour and cortisol variables calculated for all 14 sows after removing the effect of breed) indicated that 82% of the variability in the data could be explained by three factors: first, 'calmness' on which low night time frequency of major posture changes, carefulness of lying-down behaviour and high propensity to remain in nursing position after milk ejection loaded positively while cortisol concentrations during challenge loaded negatively; second, 'protectiveness' with high loadings of the reaction scores to the playbacks of piglet distress calls and the human presence near the piglets; and third, 'nursing activity' which was strongly positively associated with nursing frequency, and negatively with the proportion of nutritive nursings and baseline cortisol values. The results indicate that most aspects of pig maternal behaviour have not been significantly changed by domestication and that substantial variability in maternal behaviour exists between sows, perhaps in the form of several behaviour characteristics which encompass both behaviour and endocrine profiles of the sows. (C) 2000 Elsevier Science B.V. All rights reserved.

Abstract: We compared maternal behaviour in domestic sows and wild boar crosses (wild-type sows) to assess whether pre-parturient behaviour and/or the ability to care for offspring has been reduced and/or modified through domestication. Seven domestic sows and seven wild-type sows were used. Nest building behaviour, nursing behaviour during week 1-3 and activity measures were recorded in an outdoor environment with fat-rowing huts. There were no differences between the two genotypes of sows in the frequency or pattern of nest building behaviour. The number of nutritive nursings was reduced in the second week post partum for both wild-type and domestic sows. Domestic sows allowed their piglets to massage the udder for a longer time after milk ejection than the wild-type sows the first week of observation and tended to do the same the second week of observation. Both wild-type and domestic sows tended to terminate more nursings the second week post partum compared to the first week and wild-type sows terminated a larger proportion of nursings compared to the domestic sows. During the third week after parturition, domestic sows tended to lie down more and move less than wild-type sows. The frequency of nose-contacts between the sow and her piglets was higher in the wild-type sows than domestic sows. This study demonstrated large similarities in the maternal behaviour of wild-type and domestic sows. The few observed differences might indicate that domestic sows have adapted to some extent to a life in human protection, where it may be more beneficial from a life-time reproductive aspect to invest more in the current litter. The results suggest that the pre-parturient need of sows and the ability to care for the offspring have not been substantially modified by domestication. (C) 1999 Elsevier Science B.V. All rights reserved.

Abstract: It has been established that sows up- or down-regulate their milk production as the frequency of nursings is changed. The amount of udder massage by piglets might also influence milk production. To investigate whether these effects are associated with changes in prolactin or insulin levels, we enforced five sows each to nurse either every 35 min (MIN35) or every 70 min (MIN70) over a 26- to 28-hr period. Milk production was measured during the first 24 hr of this period. During the last three to four nursings, blood was collected every 5 min. Plasma prolactin levels increased after milk ejection (P < 0.05), whereas insulin levels increased only briefly in MIN70 sows. Sows nursing every 35 min had lower basal (P < 0.001) and maximal (P < 0.05) concentrations of insulin than MIN70 sows. There were no differences between the two groups in prolactin levels. Nursings with a postejection udder massage longer than 90 s tended to induce a higher increase in prolactin (P < 0.1) than nursings with a shorter massage. When the effects of imposed nursing frequency were removed, there was an across-sows positive residual correlation between average prolactin levels (P < 0.05) and the duration of post-ejection udder massage during the preceding 24 hr. We conclude that when milk production of a sow is changed by altering the nursing frequency within natural limits, the necessary alteration in catabolic state of energy metabolism may be associated with altered insulin levels. The duration of udder massage in a single nursing might have only a slight immediate impact on prolactin levels, but may influence prolactin levels more substantially if increased for a period of 24 hr.

Abstract: Up to 30% of nursings in domestic pigs do not result in the let-down of milk (non-nutritive nursings). The motivation to nurse often seems to be similar in non-nutritive and nutritive nursings; the sow exposes the udder and begins to grunt rhythmically while the piglets massage the teats intensively. The question arises, whether the behaviour of the piglets and sow is indeed the same during nutritive and non-nutritive nursings. We investigated quantitatively whether the latency to start teat massage, the proportion of piglets participating in the nursing, the intensity of tear massage tin terms of snout movement frequency) by the piglets and the grunting rate by the dam differ between nutritive and non-nutritive nursings. These behavioural characteristics were compared between videotaped nutritive and non-nutritive nursings in 7 sows and their litters at the age of 7-8 days after farrowing. Teat massaging movements and sows' grunts were counted during periods of 40 s one minute before (Period 1) and one and a half minute after the milk ejection (Period 2) in nutritive nursings, and during the same periods, calculated from the start of the nursing, in non-nutritive nursings. Grunting frequency was also assessed during 30 s before and 30 s after the start of the udder massage. The latency to start teat massage by the piglets and their participation in the massage were the same in nutritive and non-nutritive nursings. During Period 1 rear massage intensity did not differ between nutritive and non-nutritive nursings (13.2 vs. 18.7 snout movements, paired t-test, p = 0.23), but it did differ during period 2 (20.9 vs. 12.5, paired t-test, p = 0.024). The sow's grunting frequency was similar in the two types of nursings both before (0.27 grunts per second in nutritive, 0.22 in non-nutritive nursings, paired t-test, p = 0.216) and after the start of udder massage (0.47 vs. 0.35 grunts/s, p, = 0.148). In nutritive nursings, the grunting increased further to 0.74 grunts/s in Period I (p = 0.005), whereas in non-nutritive nursings, it remained at 0.34 grunts/s. We conclude that both the sow and her litter enter non-nutritive nursings with full motivation to accomplish a complete nursing, and it is not until the initial massage is in full progress that it is revealed in the sow's grunting that the milk ejection will fail. (C) Elsevier Science B.V. All rights reserved.

Abstract: Two experiments were conducted with the aim of investigating whether non-nutritive nursings (nursings without milk ejection), when included into a regular rhythm of nursings with milli ejection, affect milk intake and body weight gain during early lactation in pigs. In experiment 1, when the piglets were 9 to 12 days old, 8 sows were forced to nurse every 70 min three times in succession. Between the nursings, 2 piglets had an additional opportunity to massage the sow's teats from which they had been suckling. Milk intake was estimated by the weigh-suckle-weigh method. Additional massage on the two teats had no influence on milk output from those teats on subsequent nursings. In experiment 2, on day 7 or 8 post partum 16 sows were forced to nurse at every 70 min for a period of 24 h. In nine of the sows (group MIN70 + 15), non-nutritive nursing were induced 15 min after each nutritive nursing. In the other group of seven sows (MIN70), there was no opportunity for this additional massage. The total duration of udder massage was considerably longer in group MIN70 + 15 (median 271 min vs. 165 min, Mann-Whitney U-test, p < 0.005) than in the other group that did not have the additional massage. Nevertheless, the weight gain during the whole 24 h period was the same in both groups (157 g vs. 141 g, Mann-Whitney U-test. n.s.). Both groups had nearly the same decrease in weight during the 24 h manipulation of nursing rhythm in comparison with the weight gain during a unmanipulated period 24 h one day before (group MIN70 + 15 decreased 28% and group MIN70 decreased 31%, Mann-Whitney U-test, n.s.). The results suggest that additional massage provided during non-nutritive nursings does not induce higher milk output during subsequent milk ejection, either locally or systemically. (C) 1998 Elsevier Science B.V.

Abstract: A preference test was used to demonstrate that gilts have the ability to associate two sets of neutral cues with two different periods of confinement and water deprivation and to anticipate the long-term consequences of their choice in the test. Twelve gilts housed in two large, straw-bedded pens were trained to go to two sets of 12 crates, positioned on each side of a choice point, for feeding twice a day. Following initial training, the two sets of crates were marked with contrasting visual patterns and the patterns were associated with either 30 min ('short' confinement) or 240 min ('long' confinement) of confinement in the crates after entry. During 16 days of preference testing, the gilts were sent alternately to one side or the other in the mornings and allowed to.choose in the afternoons. Eight gilts chose the short confinement side more often, two, the long confinement side more often and two, each side an equal number of times, indicating that most gilts learned the association and preferred to be released shortly after feeding. However, gilts still chose the long confinement side on occasion, suggesting that they did not find 240 min of confinement very aversive. When the gilts were sent to the crates in the morning, their behaviour indicated that they expected to be released or confined depending on which crate they were in. The cognitive abilities of animals with respect to perception of time and anticipation of future events have important implications for their welfare. This study demonstrates that methods can be developed to ask animals about such things. (C) 1998 Elsevier Science B.V. All rights reserved.

Abstract: We conducted three experiments to assess how nursing frequency affects milk output in early pig lactation. In Exp. 1, nursing behavior of 12 individually penned sows was recorded on d 1 through 3 postpartum. The milk output was measured using the weigh-suckle-weigh method. The spontaneous changes in the nursing frequency between d 1 and 2 were positively correlated with the changes in milk output (rS = .64), and the same was true for changes between d 2 and 3 (rS = .77). In Exp. 2, we forced sows, 7 to 8 d after parturition, to nurse every 35 min (10 sows) or every 70 min (eight sows) for 24 h. Sows nursing at short intervals had more nursings without milk ejection, but they gave 27% more milk and their litters gained 44% more weight during the experimental 24 h than sows nursing at long intervals. Litters nursed at long intervals massaged the udder longer after milk ejection. In Exp. 3, milk output was measured after intervals of 35, 50, and 70 min imposed in varied order on 11 experimental sows in the second week of lactation. In a separate recording of two 50-min nursings, we measured milk output from teats that were, or were not, sucked at the first nursing (i.e., giving within-sow comparison of 50 or 100 min). The milk output after 35, 70, and 100 min did not differ from that after 50 min, although there was a tendency for a slight increase with longer intervals. The results suggest that glands are refilled early after milk ejection and that the increase in milk available with prolonged intervals is only slight. As a result, it is the nursing frequency that plays a crucial role in adjusting the milk output.

Abstract: It has been suggested that the function of final udder massage during nursing in pigs is to increase and/or regulate milk transfer. Using the analogy between udder massage and the begging behaviour of nestling birds, we restate this suggestion as six alternative hypotheses. Final massage may smooth the nursing-to-nursing milk output fluctuations in individual teats (Hypothesis 1) or in the whole udder (Hypothesis 4). Massage may also equalize the differences in long-term milk intake between piglets (Hypothesis 2) or between whole litters (Hypothesis 5). It is also possible that the massage acts to amplify the differences in milk intake between piglets (Hypothesis 3) or between litters (Hypothesis 6), These hypotheses lead to different predictions about the dependence of massaging on milk intake or body weight gain, and the influence of massage on subsequent milk production. The predictions were tested using data on milk intake and massaging behaviour of 12 litters during the first 3 days of life. On Day 3, significant negative correlations were found between the massaging intensity of individual piglets in a given nursing episode and their weight gain during the two preceding nursings (which supports Hypothesis 1), between litter massaging duration in a given nursing episode and litter weight gain over the two preceding nursings (Hypothesis 4),between a piglet's gain since Day 1 and its massage intensity on Day 3 (Hypothesis 2) and between the growth of a litter until Day 3 and its massaging duration on Day 3 (Hypothesis 5). With one exception, none of the predicted influences of massage on production were substantiated. The results suggest that both short-term and long-term energy balance provide a negative feedback on the motivation to massage. Further research is needed on relationships between massage and subsequent milk production and on the impact of artificial selection regimes.

Abstract: The present study examined four potential problems of group housing during calving: adoption of an alien calf owing to licking causing rejection of the heifer's own calf, failure to suck, cross-sucking and insufficient sucking during the first 6 h after birth. Observations were made on 31 heifers and their calves during the first 6 h post-partum. Licking of alien calves was quite frequent if the calving followed each other within 8 h, but the rejection of the cows' own calves was not observed. Thirteen per cent of calves failed to suck during the first 6 h. Cross-sucking calves had a tendency to suck for a shorter time. Among those calves which sucked there was little variation in time spent sucking. The time spent sucking was independent of the time of first sucking or the number of meals.

Abstract: Incidence and frequency of intersucking were observed in heifers from a predominantly Simmental herd at the ages of 3, 9, 17 and 25 months, with samples of 48, 44, 45 and 30 heifers respectively. Except at the youngest age, the observations were made just before, and repeated not later than 24 hours after, transportation to another stall. There were 81% of heifers intersucking at 3 months, and from 53% to 57% at later ages. The transport had no effect on the incidence or frequency of intersucking. The intersucking heifers had no preferred target partners. With the exception of the oldest group, those heifers which performed intersucking were themselves more likely to be intersucked than those without intersucking activity. There was also a coincidence in time between acts of intersucking and being intersucked: from 25% to 57% of intersuckings were preceded or followed within 1 0 minutes by the animal which had performed the intersucking itself being intersucked. The results suggest that intersucking exists throughout ontogeny and that it is not influenced by disturbance. It is hypothesized that in intensively raised heifers, intersucking continues until adulthood because it is not stopped by the process of weaning, which in a natural situation would be accomplished by the mother's refusal to suckle.

Abstract: Dairy cows with their calves were placed on the first day after parturition (Day 1 ) in a group of cows and calves. Each cow was removed on Day 5, after her parturition, while her calf was left in the group for a further 5 days or more so that the group contained twice as many calves as cows. The suckling behaviour was observed in order to examine the difference in the suckling of calves with and without mothers and to assess whether the cows are evenly suckled. Calves with their mothers present suckled on them almost exclusively, and did so in a 'normal' opposite parallel position on 80-90% of occasions, whereas most calves with their mothers absent suckled on more than one cow, and in a normal position on only 30-47% of occasions. Suckling was organised in closely associated suckling bouts, or 'meals'. With the removal of the mother, the frequency of meals changed, but their mean duration remained stable at 7-9 min. After the mother was removed 'the total time spent suckling fell from a mean of 6.0 to 2.3%, but increased during the following days. Because the suckling of alien calves was unevenly distributed among cows, the variation among the cows in the total time being suckled was very wide.

Abstract: The study was designed to test the hypothesis that siring success of male rats depends on when during the receptivity period the matings occur. In Experiment 1, females were mated with pairs of males differing in coat colour genetic marker. The males copulated with the female successively, either about 1 hour apart at dusk (schedule AA) or about 1 hour apart around midnight (BB) or one at dusk and the other around midnight (AB). The males mating first had lesser siring success under the schedule AB than under the other two schedules. In Experiment 2, females were mated under the same regimen as in Experiment 1. One male of each competing pair had its spermatozoa labeled by 3H-thymidine. The proportions of spermatozoa of the labeled males were identified in samples from uterine horns and oviducts. Balanced contributions of both males were recorded in uterus in all groups. No definitive conclusion concerning oviductal sperm composition could be reached. In both experiments, night-mating males copulated more quickly. It is suggested that copulation at about midnight is advantageous in intermale reproductive competition and that the function of the diurnal variation in the speed of male sexual behaviour might be clarified on this ground.

Abstract: We attempted to record directly the results of sperm competition between two male rats in samples from female reproductive tracts. Gametes of 7 male rats were labeled in vivo by repeated injections of thymidine-6-3H. 33 females were mated successively with one of the injected males and with a noninjected male, or vice versa. Samples of the resulting sperm mixtures were recovered from both the uterine horns and the oviducts of the females. Pure samples of the injected males' sperm were obtained from uterine horns of females mated solely to them. Smears of samples were evaluated autoradiographically. Except for one male, the injections resulted in a broad peak of sperm labeling with maximum intensity on days 56-58 postinjection. This labeling enabled the assessing of contribution of either male to uterine and tubal sperm in the competitive matings. The injections did not influence competitive ability of male gametes in terms of sperm transport to horns or oviducts. The outcomes of sperm competition were significantly different in the right and left sides in most female subjects. Nevertheless, the outcomes were usually similar in a horn and a tube on the same side of the body. In vivo sperm labeling appears to be a useful method in the study of rodent sperm competition.

Abstract: The effect of cycloheximide (CHX), an inhibitor of proteosynthesis, on sexual behaviour was studied in adult male rats in which it was infused into the medial preoptic area of the hypothalamus (MPOA). Sexual interaction took place under control and modification of the precopulatory behaviour of the female. Among the various bilaterally infused amounts of CHX--20 micrograms in 1 microliter, 40 micrograms in 1 microliter, 80 micrograms in 2 microliters--the effect of the largest dose corresponded to a hypothetical state of copulatory readiness of the males; 2 h after administration the males were not capable of initiating copulatory behaviour with a passively receptive female, but did so successfully with a highly soliciting female. The dependence of copulatory readiness of the males on the precopulatory behaviour of the females was confirmed repeatedly after this dose of CHX. At the same time, the precopulatory activity of the males towards a passively receptive female was unimpaired. The effect of CHX was reversible; 48 h after infusion the males displayed high copulatory readiness. Only half the males (n = 7) given bilateral infusions of 80 micrograms CHX fulfilled criterion of copulatory performance. Histological control demonstrated that the MPOA was affected bilaterally by CHX infusion in 10 males out of 14. The results are discussed from the aspect of participation of the MPOA in the regulation of male sexual behaviour. The method allows changes in sexual behaviour to be studied in the same individual in a chronic experiment.

Abstract: In the present study, both the precopulatory behaviour and the copulatory readiness of male rats following the bilateral medial preoptic area lesions was compared with their intact states. In behavioural testing, the intensity of female precopulatory behaviour was used as an experimental variable. The results showed that the natural threshold of copulatory readiness of males was increased in the lesioned state, the animals were more dependent on the soliciting patterns of the female. However, all the males exhibited conspicuous precopulatory behaviour towards the stimulus females used. Apparently, further brain structures participate in the regulation of sexual behaviour of males, above all, in activation or maintenance of precopulatory activity.

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