Impact of science and management on the welfare of egg laying strains of hens.

Posted in: Welfare by admin on January 1, 2005 | No Comments

Due to research in behaviour and welfare science, the welfare and health of egg laying flocks of chickens have improved. Genetic improvement has the ability to select birds that are healthier, have fewer metabolic and cannibalistic tendencies. The development of vaccines, improved biosecurity and training workers has also improved health and welfare. Less crowded conditions are in the future with industry making adjustments in space allocations. Other options for molting are being studied, so feed withdrawal may become a method of the past. Beak trimming, by trained personnel, should be used when non-aggressive strains are not used and / or when light intensity cannot be controlled. Information on proper euthanasia is provided by extension specialists and veterinarians. Egg producers are implementing new systems for euthanasia of spent hens. Environmental enrichment may be used in production facilities to improve environmental complexity. More research is required to determine how sound and odours affect birds.

Effects of obstructed take-off and landing perches on the flight accuracy of laying hens.

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In non-cage systems for housing laying hens, perches are an important feature of the environment. However, there is evidence of risks to hens’ welfare from collisions as they move between perches. In this experiment studies were conducted to determine the space required by laying hens to move between obstructed perches. Eighty Lohmann Brown layer hens were reared in floor pens fitted with perches from 1 day of age. After the peak of lay (25 weeks of age), their ability to jump to and from perches obstructed either by inanimate objects or by live hens was assessed in four experiments. The results of this study indicated that, while laying hens are often able to jump from or into a 15 cm space between obstructions, this requires changes in take-off and landing behaviour which incur costs in terms of energy expenditure and the risk of collision.

Foraging enrichment for individually housed horses: Practicality and effects on behaviour

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The stabled or stalled horse is commonly fed a restricted-forage diet in contrast to the varied ad libitum high-fibre diet it evolved to consume and this has been linked to the performance of stereotypical behaviour and health problems. This trial aimed to establish whether the behavioural effects observed in short-term trials when stabled horses were provided with a multiple forage diet persist over longer periods. Nine horses participated in an 18-day, cross-over, trial. Two dietary treatments were used [a Single Forage (SF, hay) diet and a Multiple Forage (MF) diet (three long-chop and three short-chop commercially available forages]. Following a 2-day acclimatization, horses were maintained on the forage treatment for 7 days. Horses on the MF treatment performed foraging behaviour significantly more frequently and for significantly longer periods than horses on the SF treatment. There were significant differences in the frequency and duration of foraging on individual forages, indicating that horses demonstrated individual preferences for particular forage. Stereotypic weaving behaviour only occurred on the SF treatment. The results of this study indicate that the potentially beneficial behavioural effects of short-term multiple forage provision do persist when horses are managed on a MF diet for a 7-day period. The results suggest that a MF diet provides a means of enriching the stable horse’s environment, by offering variety and enabling patch foraging behaviour.

Water Consumption in Early Weaned Piglets: The Effects of Adding Antibiotics

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Early weaned piglets lose an average of 6.9 ± 2.4 % of their body weight in the weaning process. They lose weight for an average of 2.4 ± 1.2 d and regain weaning weight at 3.7 ± 0.98 d. We know the growth check is a risk period. Stress, dehydration and poor feed consumption can contribute to increased incidence and severity of diarrhea. Water consumption by early-weaned piglets is important for early recovery. Up to the point of weaning, young piglets have gained most of their fluid and nourishment through nursing. After weaning they have to separate these two, consuming water and dry feed. Too little water consumption leads to dehydration. Earlier work has shown that piglets weaned into pens with water and feed show an increase in hematocrit indicative of a failure to maintain adequate water consumption. In fact transported piglets and piglets transported without water show similar increases in hematocrit. Adequate water consumption is also necessary for feed consumption. Diarrhea is often a problem at the time of weaning. Even a transient diarrhea can add to the risk of dehydration if piglets are not consuming adequate amounts of water. In this research project we asked the question: If an antibiotic were placed in the water would this reduce early water consumption due to a negative response to the taste. Forty-eight piglets were weaned at 17±1 day of age. Half of this group was placed in simulated transport for 24 hours. Immediately after arrival or following a 24 h transport, the piglets were randomly divided into groups of 4 and placed in weanling pens with feed and water. A medicated starter diet was supplied in a standard feeder. Water was supplied through standard water nipples and was gravity fed from containers that could be weighed to measure water consumption. These containers were filled with tap water or water containing an approved antibiotic at the dose on the label. Water treatments were applied for 3 days after entry into the pens. On the 4th day all pens received tap water only. Water consumption and spill were measured at 6 h, 12 h and 24 h during the first day and then daily to 4 days post weaning. Piglets were weighed daily to 7 days of age and again at 14 days. Early weaned piglets drank an average of 818 ml/day during the first 4 days after weaning. In the same period they spilled 1,353 ml/day/pig, although spill rates were highly variable from pen to pen. The taste of an antibiotic used in the water did not negatively affect water consumption of early-weaned piglets

The effect of two piglet teeth resection procedures on the welfare of sows in farrowing crates. Part 2.

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A sow’s welfare may be in jeopardy if her piglets’ needle teeth are left intact during the lactation period. The current study was designed to determine the effects of clipping needle teeth or grinding needle teeth compared to leaving needle teeth intact, on the welfare of sows housed in farrowing crates. The sows’ teats were inspected for injuries at set intervals. Sow postural and lactational behaviours were also monitored. Findings indicated that intact teeth caused a greater number of udder injuries on days 11 and 18. Teeth that were ground also caused some injury, but not to the same extent as intact teeth. Sows housed with litters with intact teeth spent more time dog-sitting than sows in the other two treatments. On day 4, sows housed with litters with intact teeth allowed piglet suckling sooner after a 60 minute bout of separation than sows in the other two treatments, but terminated post-suckling udder massage sooner than sows in the other two treatments. Sows housed with litters with clipped or ground teeth spent more time lying on their chest (without their udder exposed) than sows in the clipped teeth treatment. Leaving needle teeth intact caused injury and disturbance to the sow, as did the grinding of needle teeth, but to a lesser extent. While in farrowing crates, leaving the piglets’ needle teeth intact was not recommended.

Effect of group size on aggressive reactions to an introduced conspecific in groups of domestic turkeys (Meleagris gallopavo).

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Aggressive encounters and injuries due to head pecking seriously threaten the welfare of domestic turkeys and also result in economic losses for the turkey industry. Animals of different species show an increase in aggression when unfamiliar conspecifics are mixed but a marked drop in aggression occurs as they become familiar with each other. This experiment was conducted to investigate the effect of group size on the frequencies of different types of aggressive interactions performed by 12-week-old broad-breasted turkey toms. Non-group members were introduced for 30 min into 12 small (6 bird) and 12 large groups (30 birds) and the subsequent aggressive behaviour was observed. The members of small groups initiated more fights and delivered more aggressive pecks to the introduced bird than members of larger groups. Also birds originating from small groups initiated more fights and delivered more aggressive pecks than birds from large groups. This study demonstrates that groups of turkey toms react differently to an introduced conspecifics depending on their group size.

Dominance relationships between sows dependent on the time interval between separation and reunion.

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Regrouping of sows after weaning can be a very stressful event and this study examined the practice of introducing these sows to each other prior to breeding so that the stress during pregnancy is reduced. Sows were weaned into groups of 8 sows immediately on removal from the farrowing crate. After 4 days the sows were stalled for breeding. Eight groups were reunited into their original groups after 7 days in the stalls, while 9 groups were reunited after 28 days. The aggression that followed the initial introduction was more extensive than either of the reunions, after either 7 or 28 days. Those kept apart for 28 days fought more upon being reunited than those separated for only 7 days. So, it is possible to reduce post-breeding aggression by familiarizing pigs to each other prior to breeding, and by reuniting them after a shorter period of separation for breeding.

On-farm assessment of laying hen welfare: a comparison of one environment-based and two animal-based methods.

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Methods for assessing animal welfare at farm level are based on a range of welfare parameters which can be divided into two categories: environment-based and animal-based. Environment-based parameters describe features of the environment and management, which can be considered prerequisites for animal welfare. Animal-based parameters records animals’ responses to particular environment and management factors. The current study was designed to assess the animal needs index (ANI), which is and environment-based method, with animal-based methods such as behavioural observations and feather condition scores (FCS). All measurements were taken during a one-day visit to each of 20 commercial laying hen farms. Positive correlations were found between ANI. Positive correlations were also found between ‘movement’ and ‘comfort’ behavioural factors. A negative correlation was found between ANI and ‘wing damage (from FCS). Conclusions stated that ANI was valid and sensitive enough to show differences in animal welfare between housing systems. Differences in welfare within housing systems, however, could not be shown. Thus, ANI was an appropriate method for assessment of laying hen welfare on a large number of farms with different housing systems.

Effects of age of Holstein-Friesian calves on plasma cortisol, acute-phase proteins, immunological function, scrotal measurements and growth in response to Burdizzo castration

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Bull calves were castrated using a Burdizzo to determine the effect of age at castration on physiological and immunological stress indices. Five age groups were studied: 1.5, 2.5, 3.5, 4.5, and 5.5 months of age, or the calves were sham castrated at 5.5 months of age to serve as a control. The results indicated that calves that were castrated at 5.5 months of age had significantly higher peak plasma cortisol responses than intact calves. All calves castrated at a younger age had lower peak responses, with bulls castrated at 1.5 months having the lowest. For the first 3 hours after castration, the integrated cortisol responses were three-fold greater in the 5.5 month old than intact calves. For the following 9 hours after castration there were no significant differences in integrated cortisol responses among the treatments. The calves castrated at 5.5 months of age had significantly greater concentrations of plasma haptoglobin and fibrinogen than intact calves. These concentrations were significantly reduced in calves castrated at 1.5 and 2.5 months of age compared to the 5.5-month castrates. On the first day following castration, there was a suppression of phythohaemagglutinin-induced in vitro interferon- production in calves castrated at 5.5 months of age compared to intact calves. All castrates had increased scrotal circumferences on days 1 and 7. There was a reduction in swelling in the 1.5 month olds compared to the 5.5 month old castrates. Castration did not affect growth rate among the calves. The authors concluded that castrating calves at 1.5 months of age causes less physiological stress and inflammation than castrating at 5.5 months of age.

Identification of Pig Circovirus Type 2 in New Zealand Pigs

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