Decision support system with semantic model to assess the risk of tail biting in pigs 1. 'Validation'.

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Tail biting is a behavioural problem with both welfare and economic consequences. Various conditions that may contribute to tail biting have been identified in a number of research reports. This paper examined those reports and extracted these causative factors. A weighting factor was developed for each of these contributing conditions, and a model developed to estimate the risk of tail biting in any housing/management system. The ability of the model to predict the relative level of tail biting in two environments was assessed using treatment comparisons reported in 12 scientific papers. In total, 77 pairs of treatments were assessed, and in 63 of these comparisons the model predicted the relative level of tail biting correctly. From this the authors conclude that the model may be a useful tool in assessing the risk for tail biting in pigs. Additional testing, with provision for further modification of the model, is required.

Locomotor behaviour in dairy calves, the use of demand functions to assess the effect of deprivation.

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Demand functions are used in an attempt to measure animal motivation. In the current study, demand functions were used to assess the effect of deprivation of locomotion on the motivation to perform locomotor behaviour in dairy calves. However, when animals are deprived, there is also a pause in testing, which may be confounded with the animals’ ability to respond to the operant task. The objective of this study was to determine if the motivation to perform locomotor behaviour was consistent when the pause in operant testing varied. More specifically, the authors wanted to determine if there was a decline in the calves’ ability to respond operantly for access to an exercise arena, where it could increase its locomotor behaviour. A long pause (4 days) and a short pause (1 day) in operant testing were compared. There were three fixed ratios (FR 8, 16, or 24), which indicate the number of times the calves have to press a lever to gain access to the exercise arena. The results indicated that a pause of 1 or 4 days in operant testing did not affect the demand function based on number of rewards per session or the demand function based on overall time calves spent galloping/bucking during the rewards. Also, the length of pause in operant testing did not affect the median latency to press the panel after entering the start box or the median interval between successive number of times pressing the panel. In conclusion, responding during operant sessions was not adversely affected by increasing the number of days from 1 to 4 between operant testing.

A comparison of the welfare and meat quality of veal calves slaughtered on the farm with those subjected to transportation and lairage.

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The behaviour, physiology and meat quality of 24-week-old veal calves that were either slaughtered at the veal unit (control) or transported 3 h while provided with 0.7 or 0.95 m2 per calf and 1.5h of lairage were compared. The heart rate of the transported calves was higher during travel and lairage than the levels seen in the control calves. The transported calves also had higher plasma cortisol concentrations immediately after the travel had ceased, but had returned to levels seen in the control following lairage. The plasma creatine kinase activity immediately following travel and after lairage was higher in transported calves. The calves were not observed lying during travel. Space allowance during travel did not affect the calves’ heart rate, plasma cortisol concentration nor the plasma creatine kinase activity. The difference in space allowance during transport did not affect the frequency of potentially traumatic events experienced by the calves. The calves that underwent transport did not have a higher incidence of carcass bruising and the muscle pH 24 hours post-slaughter was similar between the control and experimental groups. The handling associated with transport and transit itself were quite stressful for the calves, however transport did not impact the quality of the carcass.

Effect of maternal presence on the development of social relationships among lambs

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This study examined how ewes influence the development of their offspring’s relationships with other lambs. In the first experiment, twins lambs were either raised with their mother in small groups or separated from the dam after birth and raised together artificially. The amount of time a lamb chose to spend with a twin or familiar pen mate was used to determine the lamb’s preference. The assessment was conducted at four-weeks of age. The lambs reared with the dam would approach their twin first and spend significantly more time in contact with their twin than with a familiar lamb. The familiar lambs reared artificially did not discriminate between their twin and a familiar lamb. Therefore, the dam’s presence is required for the lambs capable of identifying their twin. The dam tends to act as the focus of the twin lambs and therefore may directly or indirectly affects the development of the relationship between the twins. In the second experiment, 4-week old mothered and artificially reared lambs were repeatedly exposed to a contact partner. The exposure lasted five days and the lambs were exposed to one another for approximately 14 hour during the evening and 5 hours during the day. The dam was absent during the exposure to the contact partner. The distinction between an unfamiliar individual and the contact partner was assessed. As well, the behaviour was observed when placed in a pen with their contact partner or an unfamiliar lamb. In this experiment, lambs did not prefer their contact partner or the unfamiliar lamb. When the lambs were paired up with their contact partner in the pen, the artificially reared lambs bleated significantly less than when they were housed with an unfamiliar lamb. Therefore, it appears that artificially reared lambs were capable of recognizing their partner. The inability of the dam-reared lambs to be able to discriminate between their contact partner and an unfamiliar lamb may have resulted from these lambs spending less time investigating their contact partner during the exposure period. It therefore appears that the dam affects their lamb’s ability to socialize with other lambs, even when they are not present during an encounter. As well, the dam plays an important role in the development of the relationship between siblings along with lambs of the same age.

Male rank order, space use and female attachment in large flocks of laying hens.

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Male dominance, space use and eventual female attachment to certain males were studied by direct observations of male and focal female birds. Males were present at an average ratio of 1:190 females and density was 7 birds/m2. The birds were observed for territorial, sexual and agonistic behaviours as well as daytime and night time roost locations. Rank order was determined based on crowings and matings. It was found that high-ranking males used the most available space, and there was a positive correlation between male rank order and space use. However, most of the males used more than half of the area. Maintenance of the dominance hierarchy was primarily maintained by low-ranking males avoiding high-ranking males. There did not appear to be a strong female attachment to specific males.

Group housing exerts a positive effect on the behaviour of young horses during training

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In this experiment 20 horses were handled according to a defined schedule in order to assess the effects of social environment and training on the human-animal relationship. 8 horses were housed singly and 12 horses were housed in 4 groups 3 horses. Horses were handled three times per week in 10 min sessions from an age of 6 months until 2 years of age during two winter periods. The training scheme involved leading, tying up, touching, lifting feet, etc. in 43 stages. The horses had to fulfil the performance criteria of each stage in order to get to the next stage. In the first winter period, horses were led to the stable when they had ‘passed’ a stage or after 10 min of training. In the second winter period, horses would start off at stage 1 again, and when they ‘passed’ a stage they went on to the next stage within the same training session. There was a significant difference between trainers in the number of times they allowed a horse to ‘pass’ a stage within each winter period. Group housed horses ‘passed’ more stages than single housed horses and singly housed horses bit the trainer more frequently than did group housed horses. From the responses of group housed horses to training, from this experiment it was apparent that there are clear benefits of raising young horses in groups.

Serological and virologic surveillance of swine influenza in China from 2000 to 2003

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Nursing synchronization in lactating sows as affected by activity, distance between the sows and playback of nursing vocalizations.

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Nursing behaviour tends to be synchronized in lactating sows. However, the nursing synchrony has not been quantified in the sows housed in commercial conditions. In this study, the amount of nursing synchronization was quantified, the dependence of the degree of synchronization on the spatial distance between sows was examined, and the effect of nursing vocalization playback on nursing frequency and nursing synchronization 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 treatment combinations, which was age of piglets (6-10 days vs. 13-17 days), and bass frequency on the loudspeakers (bass on vs bass off). The playback of nursing vocalization was employed for three minutes every 45 min, 55 min, or no playback at all for three days. The nursing behaviour and its synchronization were recorded in two ways: through a 2 h direct interval sampling observations of all sows and through a 6 h video recording of three focal sows. The nursing synchronization was higher than the random frequency. Synchronization in pairs of sows declined with increasing distance. The playback of nursing sounds did not increase either the nursing frequency or the nursing synchronization. It is concluded that nursing synchronization is high in large rooms with crated sows, that is not a sole consequence of synchronization in general activity. Nursing synchronization depends on the distance between the sows, and an increase in nursing frequency is not always reliably induced by a playback of pig nursing vocalizations.

Prior deprivation and reward duration affect the demand function for rest in dairy heifers.

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Measurement of motivation is important in determining the relative importance of behaviours to the animals in our care. Construction of demand functions based on operant conditioning techniques is one way to measure and quantify motivation of animals. In this particular study demand functions were used in an attempt to estimate the importance of resting in cattle. Furthermore, the sensitivity of the technique was determined by quantifying the effects of variations in the level of prior deprivation, and reward (lying) duration on elasticity and intensity of the demand function. Cows were housed in tether stalls where they could be deprived of lying by attaching a girth strap secured to a rafter above the animal. During a 3-h test period a panel was placed in front of each heifer and she could work by pressing this panel on fixed ratio schedules for a releasing mechanism to be activated allowing her to lie down. In experiment 1 the heifers were deprived of lying twice daily for either two periods of 3h or two periods of 6h prior to testing. The fixed ratio varied from 6 to 24 and the reward duration was 15 minutes. In experiment 2, heifers could lie for either 10 or 20 minutes per reward at either of the two deprivation levels used in experiment 1. Here the fixed ratio varied from 10 to 50. The demand functions were liner in arithmetic co-ordinates, which means that the elasticity may not be constant across fixed ratio values. In experiment 1, heifers earned more rewards higher the deprivation level. Heifers valued access to rest more after the longest deprivation. In experiment 2, the heifers earned more rewards after two periods of six hours of deprivation when a reward duration of 10 minutes was given than when reward duration of 20 minutes was given. The results of these experiments indicate that the longest reward duration was more valuable than the shortest when the deprivation prior to test was high. The variation in elasticity with prior deprivation and reward duration has to be considered in future studies of the demand for rest in dairy cattle.

Technical Note: Effect of corticotropin-releasing hormone on adrenocorticotropic hormone and cortisol in steers.

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Activation of the hypothalamic-pituitary-adrenal (HPA) axis is the defining feature of the stress response. Under the influence of both internal and external stressors, activation of the HPA axis causes increased synthesis of corticotropin-releasing hormone (CRH) in the hypothalamus. The objective this study was to determine an appropriate exogenous dose of bovine corticotropin-releasing hormone (bCRH) to stimulate the physiological effects of the HPA axis in steers as a method to test the sensitivity of the pituitary and adrenal gland. 14-month old Holstein-Friesian steers were either given saline (control) or bCRH (0.1, 0.3, 1.0 or 1.5 ìg/kg BW). Serial blood samples were collected at -15, 0, 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 165, and 180 min relative to time 0. Following administration of 0.1 ìg of bCRH/kg BW, the peak ACTH response was not significantly different from pretreatment baseline concentrations. Administration of 0.3, 1.0, and 1.5 ìg of bCRH/kg BW increased peak ACTH above pretreatment concentrations. Peak cortisol responses to all bCRH treatments were greater than those to pretreatment concentrations. In conclusion, bCRH challenge may be a useful method for testing the sensitivity of the hypothalamic-pituitary-adrenal axis in steers subjected to stressful husbandry conditions, and a minimum dose of 0.3 ìg of bCRH/kg BW is required to stimulate physiological effects of stressor hormones.