Fear and stress reactions, and the performance of commercial broiler chickens subjected to regular pleasant and unpleasant contacts with human being.

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

The effects of regular pleasant and unpleasant interactions with humans on tonic immobility (TI), heterophil to lymphocyte ratio (HLR), body weight, feed conversion ratios (FCR) and mortality in commercial broiler chickens were studied. The following treatments were imposed for 20 days: 1) Control: the birds only experienced standard husbandry interactions; 2) Pleasant/physical: each bird was held and gently stroked for 30 seconds everyday; 3) Unpleasant/physical: each bird was held upside down, and gently swung for 30 seconds everyday; 4) Pleasant/visual: was randomly caught in its home pen and gently stroked for 10 minutes twice per day so the cagemates could see; 5) Unpleasant/visual: was randomly caught in its home pen and held upside down by its legs and swung gently for 30 seconds so the cagemates could see. After the treatments had been implemented the birds were moved from their home floor pens to three-tiered battery cages. TI and HLR responses were measured before and after the chicks were moved. There was no interaction between time of transfer and treatment. The TI and HLR were lower in the chicks from the pleasant/physical and pleasant/visual group, compared to the control group. TI was not different in the unpleasant/physical or unpleasant/visual treatments, but unpleasant/physical chicks had lower HLR ratios than the controls. The pleasant/physical treatment resulted in improved body weight and FCR. However, body weight and FCR was not affected by the other three treatments. The authors concluded that the pleasant physical and pleasant visual treatments caused a reduction in fear and physiological stress response. The unpleasant treatments did not appear to have adverse effects on underlying fearfulness, stress reaction or performance.

The Delicate Nursery Environment

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The optimal nursery environment encompasses temperature, physical, and social components. Big Sky Farms are worried about temperature control (they go from 29.0 to 19.0 degrees C) and ventilation (pigs start off with 1.5 to 1.7 cubic feet per minute up to 1.7 to 2.0 cfm). Day one is important for the piglets due to the weaning stress. To minimize this stress, it is ensured that temperatures are comfortable for the piglets, piglets are sorted by size for equal competition, they are creep fed adequately, feeders are set correctly, and provide a night light. Nursery pigs are to not be stocked at less than 2.8 square feet per pig from 5 to 24 kg, and no less than 3.2 square feet per pig from 25 to 32 kg. High standards of hygiene (washing and disinfection) are enforced to avoid a build-up of pathogenic bacteria. The piglets are fed 4 different rations throughout the nursery phase in order to increase the piglet quality that is coming out of the nursery.

Assessing dominance in sheep in a competitive situation: level of motivation and test duration

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The dominance structure in an established group of sheep is often difficult to determine in the field, because of the low frequency of agonistic interactions. One solution to this problem is to test each pair separately in a competitive situation. The most frequently used test involves competition for food after a specific period of food deprivation, but to date, there is no agreement as to the optimum length of time the animals should go without food. The present experiment compared competitive behaviour of sheep at different lengths of time after a meal. The experimental animals were a group of 10 1- year old female Scottish Blackface sheep (45 dyads). The animals had access to dry grass daily, from 07:00 to 08:00 h and from 19:00 to 20:00 h. They were tested in pairs for 5 minutes immediately after and 2, 4, 6 and 8 h after the end of the morning meal. In the test arena a feed hopper provided access to feed to only one sheep at a time. Aggressive interactions such as blocking, threats and butts, as well as non-aggressive interactions (nudges), the time spent at the feeder, and the number and type of displacements (aggressive or non-aggressive) were recorded. The number of displacements was also recorded in the home pens during ten 45-minute periods of group feedings. Blocking behaviour showed the clearest difference between the two sheep in a pair and was therefore, used as the main indicator of dominance. Its occurrence increased as the time since the morning meal was increased and decreased in the course of the 5 minute tests. Consistency between pair-tests and group observations was greatest in the test 8 h after the previous meal, but the difference in consistency between the 2 and 8 h tests was small. This experiment suggest that a period of at least 2 h of food withdrawal is necessary to generate sufficient motivation for a competition test and to mask differences in feeding motivation between individuals. While the performance of dominance-relevant behaviour increased with time since the last meal, a period of 4 h may be sufficient to provide high-quality data. We also suggest that the test duration can be reduced to 2 minutes.

The effect of early colour preference and of a colour exposing procedure on the choice of nest colours in laying hens.

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Hens at the start of lay prefer nests in the corners and at the ends of rows, which leads to overcrowding in the nest and more aggression as a result. Increased aggression leads to cracked and mislaid eggs. The current study was designed to verify whether nest colour could be used to increase their attractiveness in order to counter-balance the aforementioned positional effects. Tests were also conducted to determine whether early colour preference could be demonstrated, whether early colour preference could affect nest colour preference, and whether exposing chicks to specific colours at an early age could influence nest colour preference later on. In the first group, chicks were exposed to one of four colours (blue, green, yellow and red) during the first 12 days of life. In two additional groups, individuals showing high preference for these colours were identified. 50.5 % of chicks chose yellow most often, 32.1 % chose red, but only 7.1 and 2.2 % chose green and blue, respectively. 8.1 % of chicks did not show a preference for a single colour, but showed preference for two or three colours equally. As adult hens, they were tested for their choice of nest colour at the start of lay (weeks 19-22) from the following eight categories: those that had been exposed to blue, green, yellow or red during the first 12 days of life, those that had been selected at the same age for their preference of yellow, red, or yellow and red, and those that had been selected because they had shown no preference to any particular colour during the first 12 days of life. There were not enough birds showing a preference for blue or green at an early age to be tested later on as hens. Groups of four were created, and each bird of a group originated from a different category. Each group had a choice of four double nests, with each nest painted in one of the four colours. Hens that were exposed to blue, green or red at an early age did not prefer corresponding nest colours when in lay. The same was true for hens showing preference for red or red and yellow at an early age. All hens showed a significant preference for yellow nests when in lay, and were indifferent to blue, green, and red nests. However, birds selected for their preference of the colour yellow at an early age, as well as those exposed to yellow at that age, did not show this general preference of yellow nests. Instead, they were indifferent to all four nest colours offered. So, in systems where nests are arranged in rows, it should be possible to distribute hens more evenly among available nests, and thus avoid overcrowding, by painting the mid-third of nest rows yellow. The nests should be painted in a way as to reduce aggression between the hens and decrease the number of cracked and mislaid eggs at the start of lay.

Factors influencing bruises and mortality of broilers during catching, transport, and lairage

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The risk factors associated with mortality and bruises occurring between catching and slaughter were identified and quantified using a multilevel analysis. Some the data collected indicated that the mean percentage of dead on arrival was 0.46. After correcting the percentage of bruises for economic value, the percentage of bruises was 2.20. Bruises were associated with season, moment of transport, and ambient temperature. Factors associated with the percentage of dead on arrival were ambient temperature, moment of transport, catching company, breed, flock size, mean body weight, lairage time, and the interaction term transport time x ambient temperature. Stocking density, transport time, and lairage time were the most important factors associated with deads on arrival. These factors can be improved relatively easily and therefore increase animal welfare and profitability.

Behavior and reproductive performance by stalled breeding females on a commercial farm.

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Stereotypic behavior is an indicator of bad welfare. Gestating pigs housed in individual stalls show more stereotypic behavior than those housed in groups. However, there is not comparison in stereotypies among the gestating pigs housed in stalls. This study investigated postural behavior, stereotypic behavior in stalled gestating females on a commercial farm, and assessed the relationship between behavior and reproduction performance. A total of 609 gestating females were observed 25 times (instantaneous sampling at 15 min intervals) after feeding during 6 hr of observation period. Postural behavior (lying, standing, and sitting) and stereotypic behavior (vacuum chewing, drinker playing, and bar biting) were recorded. Reproduction data, including farrowing rate and total piglets born, piglets born alive, piglets born dead, birth litter weights, piglets weaned, and adjusted 21-d litter weights were collected. The results indicated that females showing a high frequency of vacuum chewing during gestation produced fewer total piglets born than those showing no vacuum chewing. No relationships were found between vacuum chewing and other measures of reproduction. Neither postural behavior nor the other stereotypies were related to reproductive performance. This study suggested that a subpopulation of females existed on commercial farms that frequently exhibited vacuum chewing and gave birth to fewer total pigs. High frequency of vacuum chewing in those females may be indicative of their suboptimal reproductive performance.

Influenza pandemic plan: integrated wild bird/domestic avian/swine/human flu surveillance systems in Taiwan

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Managing Welfare: On-Farm Animal Care Assessment for Pigs

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Consumers are becoming increasingly more concerned about animal welfare and want assurances that animals raised for food are handled in appropriate ways. In 2002 the Canadian Pork Council (CPC) formed an animal care working group to consider this issue and develop an on-farm welfare assessment program. This program will help identify areas on the farm which compromise welfare and will most likely be incorporated into the on-farm food safety program as a HACCP-type approach. The control points are based on measurable components of animal based and environmental and management based parameters. The current on-farm assessment consists of general sections (training, euthanasia, mortalities, etc.), sows and piglets, weaned pigs, and grow-finish pigs. Animal welfare assessments must be based on information from several different sources within a given facility. The records generated through the completion of the on-farm animal welfare assessment should provide the producer with a valuable tool for evaluating animal welfare on the farm.

On-farm euthanasia of broiler chickens: effects of different gas mixtures on behavior and brain activity.

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This study examined the effects of increasing the percentage of carbon dioxide (CO2) in the atmosphere of group-housed broilers as a method of euthanasia. Measuring the level of discomfort before loss of consciousness, and measuring the killing rate, assessed the suitability of the methods used for 2- and 6-week old broilers. The gas mixtures used in the trial for injection into the air were 1) 100 % CO2, 2) 50 % N2 + 50 % CO2, and 3) 30 % O2 + 40 % CO2 + 30 % N2, followed by 100 % CO2. At the time of injection of the gas mixture into the housing, 2 birds per trial that were equipped with brain electrodes were observed for behavior and brain activity. Of the 2-week old birds, 10 % survived the increasing CO2 percentage due to the use of mixture 3. Therefore, that particular mixture was not used in further tests on 6-week old birds. Thirty percent of the 6-week old birds survived the 50-50 mixture of CO2 and N2. Using the 100 % CO2 injection into the air, the highest percentage (42 %) of CO2 in the breathing air was reached. Only 25 % of CO2 in the breathing air was reached using the other two methods. When using each of the three mixtures, head shaking, gasping, and convulsions were observed before loss of posture. Suppression of electrical activity in the brain occurred almost simultaneously with loss of posture. The results of this study indicated that euthanasia of groups of 2- and 6-week old broilers by gradually increasing the percentage of CO2 in the breathing air up to 40 % was possible.

Effects of haloperidol, a dopamine D2 receptor antagonist, on feather pecking behaviour in laying hens.

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Feather pecking is quite similar to a stereotypy, and dopamine may have a role in the performance of stereotypies in fowl. Two experiments were conducted to examine the effects of the administration of a dopamine D2 receptor antagonist (haloperidol) on the general and feather pecking behaviours of laying hens. In the first experiment the birds were either injected with various concentrations haloperidol or saline (control) and their behaviour 30 minutes before and after the injection were recorded. A dosage of 1.0mg/kg of body weight sedated the hens, while dosages less than or equal to 0.50 mg/kg were ineffective. Therefore, the proper dosage is ranges between 0.50 to 1.0 mg/kg of haloperidol. In a second experiment, feather pecking and aggressive pecking were recorded for the 50-minute period before and after the injection of 0.50mg/kg of haloperidol or saline. Only feather pecking was significantly reduced with the administration of 0.50mg/kg of haloperidol, while it was ineffective at reducing aggressive pecking. Overall, the study verifies that feather pecking is influenced by the dopamine system.