The spontaneous qualitative assessment of behavioural expressions in pigs: First explorations of a novel methodology for integrative animal welfare measurement.

Posted in: Welfare by admin on January 1, 2000 | No Comments

Using spontaneous descriptive terms (such as ‘afraid’ or ‘calm’) to explain what animals are feeling and experiencing in different situations could be an efficient and useful way of interpreting their welfare states. However, there would have to be significant agreement shown to exist among different observers in order for this type qualitative evaluation to be useful. In this study, 18 observers with no experience with pigs were asked to independently and freely describe the behaviour of 40 growing pigs. Half the pigs were housed in an enriched environment, and half were housed in a barren environment. The observers were not aware of the different housing conditions. For the observations, each pig was moved from its home pen and observed individually in a test pen in response to the presence of a human. First, the observers watched each pig for four minutes, and then used their own words to describe the pig’s behaviour for three minutes. The results indicated that the untrained observers significantly agreed in their choice of terms to describe the behaviour of the pigs. The terms used by the observers tended to represent a continuum of behavioural expressions, eg. ‘friendly-relaxed-gentle-calm-tense-careful-cautious-restless’. The pigs that were housed in enriched pens were described as being friendly and inquisitive more than those housed in barren pens (this found in one part of the study and needs further research). The preliminary results suggest that spontaneous qualitative assessment could be a useful technique for assessing animal welfare, but further research is required.

Consistency of measurement of social status in dry-sows group-housed in indoor and outdoor systems.

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Effects of early separation on the dairy cow and calf 1. Separation at 6h, 1 day and 4 days after birth.

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This study examined the behavioural responses of dairy cows and their calves when the calf is separated from the cow 6 h, 1 or 4 days after birth. The behaviour was documented by video recordings starting an hour prior to separation and ended 21 hours after the separation occurred. Prior to separation, the younger calves tended to make more calls, move around the pen and stand more than older calves. As for the cow, prior to separation, the cows with younger calves would move around the pen more and she would also vocalize more. After separation, the older the calf was at separation, the greater amount of time it spent moving around the pen, standing, and standing with its head out of the pen. The cow’s behaviour at separation followed a similar trend as the calves. Cows weaned from their young four days after birth vocalized four times more than cows separated at one day or 6 hours. Along with a higher rate of vocalization, the vocalizations of cows that spent more time with their young after birth were also higher in fundamental frequency and a lower emphasized harmonic. Calves that spent more time with the cow after birth were on treatment for scouring for fewer days. There were no significant interaction between timing of separation and the cow’s milk production and calves’ weight gain. The intensity of the cow and calf’s reaction to separation increased with age in both the cow and calf. However, the negative behavioural response may be negated by the health advantages incurred by allowing the calf to remain with the cow for longer periods of time after birth.

Laying hen behaviour 2. Cage type preference and heterophil to lymphocyte ratios

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This study examined the reaction of laying hens to open sided and closed sided cages. In the first part of the study birds were allowed to choose between open and closed sided compartments. The birds demonstrated a preference (45-70% of birds) for open sided compared to closed-sided (15-25%) compartments in this short term assessment. The birds were then given continuous access to both compartment for 5 hours and a preference for spending time in the open-sided condition was still evident. Finally, heterophil:lymphocyte ratios were determined on birds housed long term in open and closed-sided cages. The higher ratios found in the birds in closed-sided cages indicates a higher level of stress. These results indicate that hens prefer open-sided conditions and are stressed by closed-sided cages.

Effect of manipulating feathers of laying hens on the incidence of feather pecking and cannibalism.

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Feather pecking is a problem on both economic and welfare grounds. There are several possible ways that feather pecking may spread. The simplest way is that one hen may damage the feathers of another hen, and another hen may find the damaged feathers an attractive pecking target. The objective of this experiment was to determine if damaged feathers were feather-pecked more than undamaged feathers on the same body area, and to determine whether some types of feather-body area manipulations were preferred over others as pecking stimuli. Manipulations of this experiment involved damaging the feathers on the rump, tail or belly of different hens with two or three levels of severity of manipulation. Sixteen groups of hens between 26 and 28 weeks were observed. Damaged feathers received significantly more severe feather pecks than undamaged feathers. The feather-body area manipulations that received the greatest number of severe feather pecks were the tail feathers when they were cut very short, the rump feathers when they were trimmed, and the rump when feathers were removed. The results of this experiment suggest that feather pecking does indeed spread through flocks by damaged feathers becoming an attractive target for feather-pecking behaviour. This finding is important in that it suggests that feather pecking can potentially spread through a flock if there is at least one hen in the flock that will start to damage feathers.

Working for a dustbath: are hens increasing pleasure rather than reducing suffering?

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When hens are housed in cages, they are unable to dustbathe. The cause to dustbathing has been researched quite thoroughly over the years, while the importance of this behaviour to the hen is not yet known. Various trials have determined that hens have a need to dustbathe. This study examined a hen’s willingness to work to obtain dustbathing substrate by making her pass through a swinging door that has a certain amount of weight attached to it. The hens were trained to push through the door to gain access to peat moss. The goal of the study was to determine the maximum amount of weight a hen was willing to work against to gain access to the peat moss. Some hens were deprived access to any dustbathing materials in their cage and were compared to those whom were not. The hens that were deprived of dustbathing materials tended to push more weight and make more attempts to move the door than those that were given dustbathing materials. Those that were deprived of dustbathing material also performed significantly more dustbathing bouts when they accessed the peat moss, showing a motivation to dustbathe. This study found that even though deprived hens to have the motivation to dustbathe, they may not work to access the substrate if they recently have had an opportunity to dustbathe. This behaviour seems to more opportunistic than a need due to their willingness to work for the substrate.

Modifying the cage to accommodate behaviour.

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Night-time roosting in laying hens and the effect of thwarting access to perches

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The undisturbed roosting behaviour and the reaction of commercial laying hens when roosting on perches was thwarted were studied. Hens were kept in two groups of 26 in litter pens with perches at heights of 23, 43, and 63 cm. Immediately after lights-out and within ten minutes, over 90 % of hens were on perches provided and roosting close together (experiment 1). In experiment 2, hens were kept in groups of three in experimental pens equipped with perches. The birds were tested in four different situations: (1) the pen unchanged (Base), (2) the perch was covered with plexiglass, (3) the perch was removed, and (4) the unchanged pen (Post; control treatment). All birds experienced the four treatments. When perching was not possible, the hens spent less time sitting and tended to spend more time standing than the control hens. The hens also moved more when the perch was inaccessible. When the perch was visible but inaccessible, the birds showed more attempts to take off. The authors interpreted the findings to mean that the birds were experiencing increased frustration and/or exploration, probably to find an alternative roosting site. These results and the findings that there was a high use of perches for night-time roosting under undisturbed conditions led the authors to conclude that laying hens were motivated to perch. They also concluded that hens kept under conditions where perching is not possible may cause the birds to experience reduced welfare.

A note on possible link between behaviour and the occurrence of lameness in dairy cows.

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The number one welfare concern and one of the more important economic concerns in dairy cattle is lameness. There are numerous causes of lameness. What remains unclear is why certain individuals within the same environment are more prone to foot lesions than others. It is thought that differences in social and individual behaviour may be the underlying cause of these differences. The incidence of lameness in 40 dairy cows was compared with their social behaviour and individual time budgets. The cows’ agonistic and individual behaviours were videotaped. From these tapes the cows social status was determined and cows were categorized as low, middle or high ranking. The rate of lameness during this study was 42%. Social rank did not affect the amount of time the cows spent standing. Low ranking cows did, however, spend more time standing still in the passageways and standing halfway in the cubicle than middle or high ranking sows. The amounts of time spent standing did not differ between lame cows and cows that were not lame. Cows that did become clinically lame did stand half in the cubicles longer and were displaced from the cubicles less than cows that were not lame. This study may offer future researchers an idea of the direction to go when trying to study the relationship between behaviour and lameness.

Growth, carcass characteristics, and incidence of ascites in broilers exposed to environmental fluctuations and oiled litter.

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Using male broilers, the impact on growth, carcass characteristics and occurrence of ascites was tested by manipulating the diurnal temperature and application of canola oil to the litter to remove respirable dust. The temperature fluctuated 3C above the set temperature during the day and 3C below the set nightly temperature, while the control birds were kept at a constant temperature. The oil was applied to the litter every second week at a rate of 1.1 L/m2. . Once the chickens reached 6 weeks of age 30 out of the 150 chickens in the pen were slaughtered and their carcasses weights of the breast muscle, fatpad and hearts were taken. Acites lesions were also scored at this time and the areas of each chamber of the heart. Broilers that had oil applied to the litter gained significantly less weight than those that did not have oil applied to the litter (2 249 vs 2 293g). The various treatments did not result in a difference in fatpad weight, shank length, lung weight and percentage of breast muscle. However, the pectoral muscles were significantly heavier and the right ventricle was heavier in broilers that were exposed to temperature fluctuations. Broilers on the temperature fluctuation treatment had a higher mortality rate of 1.4%. It was concluded that fluctuations in temperature can negatively effect broiler growth, and the impact is more distinct when the litter is coated with excessive amounts of oil.