Influence of replacement rate on the welfare of sows introduced to a large dynamic group.

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Dynamic social groups are common in sow management. In these groups new animals are added to a resident group at regular intervals, from weekly to every 3-5 weeks. The newly introduced animals are subject to aggression from the resident animals and other newcomers. A question that arises is to what extent does the proportion of animals that are added to the dynamic group affect the aggression and social interaction of the new sows. This study compared the post-grouping injury levels and social integration of sows when 10, 20, 30 or 40% of a dynamic group was replaced. The dynamic groups were comprised of 40 sows. Replacements took place at three-week intervals. Three days prior to new sows being added to the group, 10-40% of the sows were removed. Replacement animals had been housed in groups of 4 for 5 weeks prior to being added to the dynamic group. This is a common procedure that is used for breeding weaned animals. One to four of these groups of 4 sows were added to the dynamic group, representing 10, 20, 30 and 40% replacement rates. Newly introduced animals were exposed to similar amounts of aggression regardless of the replacement rate. However, as replacement rate increased the proportion of aggression derived from other newly introduced sows increased as well. Injuries after one week were similar for all replacement rates. Sows introduced in the 10% replacement treatment spent more time lying outside the kennels (prime sleeping areas) during the first week than did the newly introduced sows in the higher replacement rate treatments. All introduced sows gradually increased their contact time with resident sows over the first week. It would appear that replacing less than 10% of the sows in a dynamic group is quite stressful for those newcomers. Increasing replacement rate beyond 20% does not further reduce the stress on new sows.

Dustbathing by broiler chickens: a comparison of preference for four different substrates.

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A common welfare concern with broiler chickens is leg abnormalities. However, recent research has shown that allowing broiler chickens to exercise in the form of performing natural behaviour such as perching, walking on inclines and dustbathing can improve a chicken’s ability to walk. The hope is to improve leg condition of broiler chickens by increasing the amount of dustbathing that the perform, and to increase the performance this study examined the preferences that chickens had for certain substrates to use for dustbathing. The dustbathing substrates compared were pine wood shavings, rice hulls, construction grade sand and recycled paper animal bedding. Testing began at one week of age and ended at seven weeks of age, each week four new chickens were tested. Prior to testing, the broilers were housed on wood shavings, but during testing they were not given bedding. During testing each corner of the pen was filled with one of the test substrates. The dustbathing behaviour of the birds was measured by counting the number of vertical wing shakes. Significantly more wing shakes were performed, more visits were made and more time was spent in the sand than the other three substrates. Before dustbathing, the chickens typically ground peck which was perform more frequently and more often in sand. The preference to use sand to dustbathe was observed at one week of age and remained consistent throughout the remainder of the trial. This study found that sand is a very attractive substance for dustbathing and also stimulates dustbathing. The next step is to determine if the provision of sand increases dustbathing to a point that helps to improve the leg condition of broiler chickens.

Reassortment of influenza A virus genes linked to PB1 polymerase gene

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

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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 contributing factors, ranked from those most to least likely to affect tail biting were: tail docking, diet, substrate, weaning environment, sex, weight or age, food related agonism, growth retardation, worms, space per pig, trichinosis, heat, season, floor type, ventilation type, feed moisture, feeding synchrony, group size, feeding automation, time of day, tail injury, coldness, water provision, breed, herd size, light, air quality and group stability. The model can be upgraded as new information becomes available.

Effect of individual versus group rearing on ethological and physiological responses of crossbred calves.

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The differences in behaviour and physiology of calves housed in groups or individually were examined. The observations and measurements were made one hour before and after the morning and afternoon feedings at 2, 4, 6 and 8 weeks of age. The behaviours of interest were feed and water consumption, rumination, licking of objects within the pen, cross-suckling (sucking on body parts of penmates), stereotypies, play behaviour, standing, lying, grooming and restlessness. The physiological variables examined were respiration and heart rate as well as, rectal temperature. The calves were fed colostrum the first three days after birth and were then switched to a milk based diet. At two weeks of age the calves were also provided with calf starter and fodder. The calves that were housed in groups spent more time consuming solid foods, took less time to consume their milk, licked objects throughout the pen more, and cross-suckled more frequently. Individually housed calves spent more time idly standing, sleeping and lying. Rumination did not begin until after 2 weeks of age and was more frequently observed in group-housed calves. The rectal temperature and respiration and heart rates were not affected by housing. By housing calves in groups there welfare can be improved because the calves learn to eat more solid feed at an earlier age, they have access to more free space and are more active, and are provided with the opportunity to interact socially with other calves.

Effect of the manger space on welfare and meat quality of beef cattle.

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Simmental bulls were raised in separate pens with one of two different manger space allowances: 60 cm per head versus 80 cm per head. Floor type was either slatted or straw-bedded. There were no significant interactions between the two main factors considered in the study. Daily gain, feed intake and feed efficiency were not affected by the amount of manger space provided to the bulls. Similarly, manger space allowance did not modify behaviour or the neutrophil/lymphocyte ratio, which is a blood indicator of chronic stress. Ad libitum feeding promoted a high turnover of bulls in the feeding area, which limited the number of animals that could eat at the same time. This occurred regardless of the amount of manger space provided. Carcass traits and meat quality were not affected by manger space allowance. Regardless of whether bulls are housed on slatted or straw-bedded flooring, a 60 cm per head space allowance at the manger is sufficient if fed ad libitum under intensive rearing conditions.

Effects of handling at weaning on manageability and reactivity of foals

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Since behavioural problems can render a horse unsuitable for inexperienced riders, the horse’s temperament, including its manageability, reactivity and/or fearfulness, is of importance. Handling during infancy and other early-life experiences may influence a horse’s adult behaviour. It may also reduce its fear of humans and other frightening situations. Studies on cattle and goats have found handling around the time of weaning to be effective in increasing ease of handling. This study was designed to test the effects of handling young horses around the time of weaning. Horses were handled for either 12 days immediately following weaning (‘early handling’) or 21 days later (‘late handling’). Haltering, gently petting all parts of the horse’s body, picking up its feet, and leading the foal over 120 meters all constituted ‘handling’. Foals that had not been handled served as the control treatment. During handling sessions, ‘early handling’ foals were easier to handle than ‘late handling’ foals. In other words, the times taken to equip the foal with a halter, to pick up its feet, and the ‘walk-ratio’ (time walking under constraint/total time walking) were lower for ‘early handled’ foals. Tests conducted two days, four months, seven months, 10 months, and 18 months after the end of the handling period showed that ‘early handling’ and ‘late handling’ foals were easier to handle and were less reactive than control foals, although the differences lessened over time. The results of this study indicated that the post-weaning period can be qualified as an ‘optimal period’ for handling, and that the effects of handling during the post-weaning period can persist for at least 18 months.

Influence of group size during the post-weaning period on the performance and behaviour of pigs.

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Increasing the group size of weaned pigs in commercial systems has potential benefits in terms of leading to more efficient use of resources and greater ease of management. There are concerns, however, about the effects of increasing group size on productivity and welfare. Another concern in commercial systems is the effect that group size during the post-weaning period has on performance during the finishing period. In some production systems, pigs which are housed in large groups during the post-weaning period may have to be split into smaller groups during the finishing period in order to suit finishing accommodation. This regrouping may lead to increased stress and may in turn lead to reduced productivity. The aim of the present study was to assess the effect of increasing group size up to 60 pigs per group on performance and behaviour during the post-weaning period (4 weeks of age until 10 weeks). In addition, the effects on performance of splitting groups of 40 and 60 pigs into groups of 20 pigs at the start of finishing period (11 weeks of age until 21 weeks of age) was tested. Group size did not significantly affect growth rate and feed intake, however food conversion tended to be poorer in groups of 40 and 60 pigs than in smaller group sizes. Behavioural observations did not show any difference among the group sizes in the proportion of small, medium and large sized pigs at the feeder, or in the total number of pigs at the feeder. In addition the overall aggression at the feeder was similar in all group sizes. Food conversion ratio was poorer in groups split from 60 pigs than in groups of 40 pigs, or in groups which were kept in group size of 20 pigs throughout the growing and finishing stages. The results suggest that the group size of weaned pigs can be increased from 10 to 60 animals without any significant adverse effects on performance or welfare during the post-weaning period. If the pigs are to be housed in groups of 20 during the finishing period then it may be better to house pigs in groups of 40 rather than in groups of 60 pigs during the post-weaning period, in order to reduce negative effects on food conversion during the finishing period.

Sociability and the willingness of individual sheep to move away from their companions in order to graze.

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Discretely distributed patches of vegetation may cause sheep to have to decide between moving away from companions to graze better vegetation or remaining in close contact with companions. In this type of situation, sheep may have lower intakes or poorer diet quality if they have high levels of social motivation. The objective of this study was to determine if the level sociability (the tendency of individuals to be close to others when grazing in a group) would effect the distance they would be willing to move away from their companions in order to graze long (preferred) grass. Sheep were tested to determine if they would be willing to move 0 m (control), 15 m (near) or 35 m (far) away from their companions. Initially, nearest neighbour calculations were determined, which are estimates of the relative proportion of time that individuals were observed to be nearest neighbours of other sheep. Sheep that were determined to be very sociable and those that were determined to be unsociable were used in this study. The very sociable sheep tended to stay closer to the group and spend less time grazing on the long grass compared to the unsociable sheep. Unsociable sheep took more grazing bites on the long grass than the sociable sheep during the near treatment. When the trade-off between grazing or staying close was relatively small, then sociability was reflected in foraging strategy. However, other motivations, such as fear of isolation, may have affected the willingness to move away when food was further away.

Existence of reassortant A (H1N2) swine influenza viruses in Saitama Prefecture, Japan

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