Do pigs form preferential associations.

Posted in: Welfare by admin on January 1, 2004 | No Comments

Pigs have been shown to prefer associating with certain groups of pigs over others, for example their mother and littermates over other group members. However, few studies have properly examined whether long-term preferential associations or ‘friendships’ are formed between pairs of pigs within a group. The aim of this study was to determine whether pigs form long-term preferential associations, based on lying partners, and to examine factors that may influence the formation of these associations. Thirty three pigs from 16 litters were housed together from 4 weeks of age. At 10 weeks they were split into groups of 16 and 17 pigs and introduced into the two pens (1st pen). At 17 weeks the two groups swapped pens (2nd pen). The lying patterns of each group were recorded over 3 weeks in the 1st and 2nd pens. The existence of preferential associations was identified in both groups. Of the 33 pigs observed, 32 formed preferential associations with one or more pigs in their groups. These findings suggest that unrelated pigs are capable of forming preferential associations. However, it is unclear whether such associations are widespread or important to pigs, since most dyads’ preferential associations were not consistent between pens.

Between breed genetic variation for welfare-related behavioural traits in domestic fowl.

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A multi-breed experimental design was used to estimate the between breed genetic variation for feather pecking and cannibalism, behavioural time budgets, and measures of fear, sociality and coping strategy in domestic fowl. Past experiments have primarily been within breed experiments or ones comparing two lines. There was a great deal of between breed (genetic) variation in feather pecking, cannibalism, and general pecking behaviour in the current study. No evident for between breed genetic variation in time budgets was found. Evidence for fear and coping strategy was slight while some measures of sociality were moderately high. Between breed genetic correlations between behavioural traits and feather score, skin score and mortality were low. Correlations between skin lesions and sociality and culling were labile. Conclusions stated that there was a strong genetic basis from damaging feather pecking and cannibalism and the behaviours were not strongly related genetically to other behavioural traits.

Sex differences in equine learning skills and visuo-spatial ability.

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In the majority of the species studied to date, males have more advanced visual-spatial capabilities. The sex differences in the visual-spatial abilities of horses are yet to be determined. The visual-spatial abilities of male and female horses were assessed during a series of six tests involving a novel test apparatus. The test apparatus contained four adjoining stalls. Each stall contained a feed bin and a moveable barrier, and the barrier controlled and limited the access that the horses had to the feed bin, except in one stall. Males completed each of the six tests significantly faster and made fewer errors than the female horses. The male horses also complete significantly more of the tests than the females. The males horsed took significantly longer to complete the first task than tasks two to five. This difference was not found in the female horses. Thus, based upon the behaviour of the horses in the tests, the males demonstrated that they have much more acute visual-spatial abilities than female horses, which is similar to the findings of other species.

Effects of repeated stress during pregnancy in ewes on the behavioural and physiological responses to stressful events and birth weight of their offspring.

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Stressors are frequently encountered during the pregnancies of farm animals. The effects of thee stressors on the development and subsequent responses of the offspring has been poorly studied. In this study the authors subjected pregnant sheep (ewes) to either no stress or repeated isolation in the presence of a dog during the last five weeks of gestation. During their initial exposure to the dog while isolated from their flockmates the ewes had a significant increase in plasma cortisol. Although the ewes habituated to this stressor over several exposures, their unborn lambs were exposed to elevated levels of cortisol on several occasions. These ‘stressed’ lambs were larger at birth than those from unstressed ewes. The stressed lambs were also more explorative (at 8 mos of age) and had higher levels of cortisol (at 25 days of age) than the lambs from unstressed ewes. Exposure of a pregnant ewe to stressful conditions had significant effects on the physical and behavioural development of her lambs. These effects may be adaptive for the offspring, even though the experience represented a significant stress for their mother.

The influence of climatic conditions on physiological parameters in dairy cows kept in open stables.

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Traditionally, dairy cows in northern and central Europe were kept in tie-stalls and in closed stables. Nowadays, however, loose housing systems are preferred to reduce labour input with increasing herd sizes as well as to meet animal welfare requirements. This study aimed to assess whether cows are able to cope with the range of climatic conditions they are exposed to in open stables on commercial farms in central Europe. On each of four farms, ten lactating cows were observed over a total of five weeks in winter, spring and summer. Based on continuous measurements of air temperature and relative air humidity a mean value of a temperature humidity index (THI) was calculated for each farm and each observation day for night and day. THI had significant effects on skin temperature and body surface temperature both during night and day. Rectal temperature, duration of lying and cortisol concentration in the milk was significantly affected by THI during the day but not during the night. Heart rate and frequency of lying did not significantly covary with THI. The results of this suggest that climatic conditions prevalent on the farms during the day induce stronger thermoregulatory responses than the conditions during the night, but did not overtax the animal’s capacity to adapt. Consequently, the housing of dairy cows in open farm buildings should not result in animal welfare problems under the climatic conditions measured on the study farms.

Diseases: What You Can do to Prevent Them

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Dr. John Harding offers his opinion on 3 health issues that are limiting the productivity and financial returns in Western Canada. Piglet scours has a negative impact on growth rate and efficiency, and should be somewhat easy to control, but has proven to be rather difficult. Scours can be prevented by attaining a diagnosis on the specific infectious agent, improving sanitation, improving farrowing hygiene, creating a comfortable environment, treating all cases promptly, enhancing breeding herd immunity (vaccinations or feedback), and establishing good farrowing barn routines.

“Suis-ide” diseases refer to meningitis, septicaemia, arthritis, and heart valve infection. These diseases can cause severe illness or even sudden death. The specific strain should be cultured from the source of infection for preventative measure as well as for treatment procedures for the specific strain. These diseases can be prevented by again finding a specific diagnosis, mass medication programs, sanitation, adopt all-in-all-out rooms, reduce environment stress, vaccinate, and treat individual pigs. Condemnation originating in the finisher barn is the third area. Arthritis and abscesses are the most common problems. These directly affect the processing because of the consumers demand for a quality product. Some causes of condemned carcasses include retained testicles (ensure proper castration), tail chewing (provide toys for pigs to chew on), chronic arthritis (treat promptly), adhesions (aggressively treat respiratory diseases), milk spot livers (improve sanitation and de-worm), and erysipelas (vaccinate or treat).

The effect of litter size and littermate weight on pre-weaning performance of low-birth-weight piglets that have been cross-fostered.

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Pre-weaning performance of piglets who had been cross-fostered was compared to evaluate the effects of litter size and littermate weight on low-birth-weight piglets. Litter size was either 8 or 12 piglets. Low-birth-weight piglets were housed with either an equal number of heavy-birth-weight piglets, an equal number of average-birth-weight piglets, or in a group of all low-birth-weight piglets. A resulting six groups (treatments) were created. In large litters, the mortality of low-birth-weight piglets housed with heavy-birth-weight piglets was greatest. In small litters, mortality of low-birth-weight piglets housed with heavy-birth-weight piglets was no different. Neither littermate weight, litter size, nor the interaction between the two affected weight gains of the piglets until day three post partum. Conversely, littermate weight, litter size, and the interaction between the two did affect weight at 21 days post partum. Low-birth-weight piglets in small litters had a significantly higher 21 day weights than piglets in large litters. In large but not small litters, low-birth-weight piglets were absent at more nursing episodes and spent more time fighting over teats than their heavier littermates, whether housed with heavy-birth-weight piglets or average-birth-weight piglets. Conclusions stated that littermate weight may affect performance of low-birth-weight piglets due to direct competition for access to a functional teat.

The effect of claw and beak reduction on growth parameters and fearfulness of two leghorn strains.

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Two strains of leghorn chickens were used to test a technique for sterilizing the germinal tissue of the claw with microwave energy and the beak tissue with infrared energy for trimming the claw and beak of the birds. Claw sterilizing was carried out on half of the birds while the other half of birds were left intact. Of the claw-sterilized birds, one third of them were beak trimmed at hatch using the infrared technique, one third were precision trimmed at 7 days of age, and the beaks of the remaining third of the birds were left intact. Birds that had been claw-sterilized had a significantly lower body weight, except from weeks 3 to 6, and had a lower feed consumption from week 8 to 18. The birds that were beak-trimmed at hatch had a lower body weight from week 3 to 14 and ate less total feed by the fourth week. Mortality was lower than 2.1 % for all treatments. Using a fearfulness scoring system of 1 to 10, from week 6 to 8, birds with intact claws peaked at 8 to 10 and birds that had been claw-sterilized peaked at 3 to 4. The fearfulness score subsided to 2 to 3 and 6 to 8 for claw-sterilized and non-claw-sterilized birds, respectively, by week 16 to 18. Pullets were able to be grown to sexual maturity on less feed and with a lower level of observed fearfulness using standard husbandry practices when they were beak-trimmed and claw-sterilized at hatch.

Behavioural aspects of feeding constraints: do broilers follow their hut feelings?

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Many trials investigating issues relating to the feeding and growth of broiler chickens do not include behavioural observations. One example is the work by Burkhart et al. (1983). They proposed that one of the associated changes in broiler chickens as a result of selection for lean, efficient growth is alterations to satiety mechanisms in the brain leading to excessive food intake and compulsive feeding behaviour. They compared fast and slow growing chickens with or without ventromedial hypothalamic (VHM) lesions, and found not changes in the fast growing strains, but increased fat deposition in the slow growing strain. However, no behavioural measures were examined, and a reduction in activity of the slow growing line as a result of VHM lesions would offer an alternative explanation of the results. The present paper briefly outlines some of the vast body of research which has been carried out on different aspects of feed intake and growth of broilers in order to highlight the multitude of disciplines involved and factors at play. One reason for the paucity of trials which incorporate behavioural aspects of feeding may be, that the study of feeding behaviour in the broadest sense span two quite diverse scientific objectives. One is concerned with satiety and the mechanisms behind intake control. The other is concerned with daily feed intake, which is one crude measure of feeding behaviour, and the resulting growth and efficiency. However, feeding behaviour and other behavioural aspects of feeding often play an important role in the interpretation of production results. Conversely, many behavioural studies of growing animals, such as modern broilers, would benefit from a more stringent incorporation of nutritional data and discussions of non-behavioural aspects of growth. More studies of the interactions among physiological capacity, genetic potential, and social effects on feeding behaviour and activity of broilers would greatly improve our ability to interpret experimental results.

A short note on effects of exposure to a novel stimulus (umbrella) on behaviour and percentage of eye-white in cows.

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Fear response in dairy cows was studied in response to exposure to an unfamiliar umbrella that was suddenly opened 0-2 m in front of the cows. Eye-white percentage was tested as an indicator of fear experienced. All animals showed startle and avoidance responses when first exposed to the opening umbrella. Compared to 30 seconds before the umbrella was opened, there was a significant increase in avoidance and percentage of eye white during a 30 second (avoidance) and 60 second (eye-white) observation period after the umbrella was opened. Based on these results, the percentage of eye-white may be a useful gauge of fear experienced in dairy cows