Immunocompetence and viability under commercial conditions of broiler groups differing in growth rate and antibody response to Escherichia coli vaccine.

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

An increasing amount of loss due to mortality and morbidity is being seen in the broiler industry, however if the chickens are bred to have increased disease resistance these losses may be reduced. The study examined the impact that breeding broilers to have a stronger immune response to Escherichia coli would have within a commercial broiler population. Comparisons were made between hens with high or low responses to E. coli vaccination, commercial broilers and crosses (high x commercial, low x commercial and high x low). The chicks were test under a standard vaccination program during 1997 and 1998. All incidences of mortality were recorded, while body weights and blood samples to determine the anti-body response of natural exposure to E. coli and vaccination with Newcastle disease virus was taken from a sample group within the pen, depending on group size. The commercial line had the highest growth rate, moderate growth rates were seen in the high x commercial and low x commercial line, and the slowest growth rates were observed in high, low and high x low broilers. The highest antibody response was seen in the high line and the lowest response can from the low line. Moderate antibody responses were seen in the crosses and the commercial line, the lowest response out of the three from the low x commercial line and the highest from the high x commercial line, with the commercial line between the two. There was a high strong correlation between the chickens’ antibody response to Newcastle disease and E. coli, which may indicate that there is a common genetic component in the immune response to these antigens. The commercial line had the highest mortality rate and the lowest mortality rates were seen in the slowest growing lines (high, low and high x low). The mortality rate of the low x commercial line was 33% higher than the high x commercial line. The results indicated that there might be an interaction between the antibody response and growth rate on the mortality due to infectious disease

The pros and cons of cages.

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Limb injuries, immune response and growth performance of early-weaned pigs in different housing systems.

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Using a range of indicators, the welfare of early-weaned piglets housed in different systems was examined. At 6.4 kg liveweight, piglets were allocated to either a) deep-straw; b) Straw-FlowA

Behavioural responses of broilers to different gaseous atmospheres

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This study was conducted to determine the reaction of broilers when they first come into contact with various gas mixtures, some of which can be used for stunning prior to slaughter. The birds were exposed to either air, 90% argon, 60% CO2, 40% CO2 and 30% O2, or 70% argon and 30% CO2. There were no differences in behaviour before entering the chamber or when the birds first arrived. Headshaking and gasping are typical reactions to CO2. The number of birds showing such behaviour was least in the 90% argon mixture, and was reduced in the CO2/O2 mixture compared to the other combinations that included CO2. Loss of posture (falling) is indicative of the animal loosing conciousness. Among the non-air treatments, this occurred first in the Argon/CO2 combination. In conclusion, the birds did not appear to detect or avoid increased CO2 levels when first exposed to the mixtures, high levels of O2 in the mixtures reduced the negative reactions of birds exposed to CO2, and Argon was effective in achieving rapid loss of consciousness.

Effect of male-to-male aggressiveness and feed-restriction during rearing on sexual behaviour and aggressiveness towards female by male domestic fowl.

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The present experiment was conducted as part of larger study investigating problems of aggression towards females by male broiler breeder fowl. The study investigated (1) if feed-restriction during rearing affects behaviour towards females at sexual maturity and (2) if aggressiveness towards females is correlated with general levels of aggressiveness. The study compared broiler breeder males with commercial laying strain males, which were either fed ad libitum or were feed-restricted during the rearing phase, and with game strain males, bred for fighting. Laying strain males did not behave aggressively towards females, whether feed-restricted or fed ad libitum. Game strain males also were not aggressive towards females. Broiler breeder males displayed higher levels of aggression towards females than did feed-restricted laying strain males. Females struggled more frequently during mating attempts by broiler breeder males and interfered frequently when these males attempted to mate with other females. The results of this study indicate that aggression towards females appears to be a unique problem occurring in broiler breeder male strains and not a function of feed-restriction.

Thwarting of behaviour in different contexts and the gakel-call in the laying hen.

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Earlier studies have shown that thwarting of feeding behaviour in the laying hen is expressed through a specific vocalization, the gakel-call. The first aim of this study was to investigate whether the effect of deprivation per se on the occurrence of gakel-calls can be distinguished from the effect of the additional frustration. Frustration is defined as the state of an animal that results from nonreward in the expectancy of reward. The second aim was to investigate whether the occurrence of gakel-calls is restricted to a food context or whether it can be regarded as an expression of frustration in general. For this purpose, 20 hens were deprived of food, water and dustbath. After deprivation at a fixed time, a cue was given and the hens were rewarded with access to food, water or dust during a 15-min session on 4 consecutive days. On the fifth day, they were thwarted in the associated behaviours by blocking the access to these commodities, after the hens had been presented the signal that previously preceded that reward. We then recorded behaviours that might reflect the state of frustration in three 15-min periods. The period ‘Pre-Frustration’ started 15 min before ‘Frustration’. This, in turn, was followed by the period ‘Post-frustration’ in which the hens were rewarded again. Nesting behaviour was thwarted by blocking the access to the nest (Frustration) after a hen had reached the last stage of its prelaying behaviour.In the food, water and dustbath context, deprivation elicited gakel-calls. The additional frustration resulted in a higher number of gakel-calls in all contexts except the food context. However, together with the findings of previous experiments, the results of this study suggest that frustration, in general, is expressed through the gakel-call. Frustration in the nest context elicited more gakil-calls than the other contexts. This latter finding is discussed in the light of occurrence of the gakel-call under natural circumstances.

Stunning of poultry.

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Hoop housing for feeder pigs offers a welfare-friendly environment compared to a nonbedded confinement system.

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The trend in swine production during the last 50 years, in North America, has been to move away from outdoor, open, dirt-lot systems to a totally confined systems. The economy of scale offers farmers a significant income on a commodity that provides little revenue on an individual pig basis. There are several important differences in the two production methods in terms of swine welfare. The outdoor system typically provides a greater amount of space per pig and thus allows swine the freedom to move and choose an environment. The outdoor systems offers several disadvantages as well. Pigs may be exposed to environmental temperature extreme that could negatively affect their welfare and could be challenged with disease that cannot be eradicated from the soil. The move to a confinement system has helped to eliminate the welfare concerns of thermal stress and disease that challenge outdoor swine. Because total confinement systems are expensive to build and maintain compared to less intensive systems the producers have become interested in an inexpensive alternative: hoop structures (Hoop) recently. The hoop use bedding to keep the pig dry and allow this bedding to compost beneath the pigs to keep them warm in the winter. This study compared the behaviour and physiology of pigs in a nonbedded confinement system (NBCS) with those in the hoop. Two experiments, 1 in the winter and 1 in the summer, assessed the welfare of pigs based on the incidence of aberrant behaviour, physiology responses to handling, incidence of lameness, and the performance of play behaviour. Pigs raised in NBCS performed more aberrant behaviours and less play behaviour, had greater plasma cortisol response to handling (but fewer vocalizations), and a greater incidence of injuries than did the pigs raised in Hoop. Based on these data, pigs in the Hoop were adjudged to have enhanced welfare as compared to pigs raised in the NBCS. Because the welfare of pigs in the Hoop appears to be greater than the welfare of pigs raised in the NBCS, future research should be determined which factors are most important to pigs and then try to incorporate these into production systems.

Effect of a trainer cow on health, behavior, and performance of newly weaned beef calves.

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A similar protocol was followed in three experiments: a trainer cow was randomly assigned to half the pens of recently weaned calves. Data on physiology, behaviour and performance were collected. Trainer cows did not affect rectal temperatures, requirements for antibiotic therapy, white blood cell counts, neutrophil:lymphocyte ratios, or leukotoxin antibody titers. There were no overall differences in weight gain. Trainer cows did not affect the frequency and duration of visits to the bunk. The number of calves observed eating increased. The presence of a trainer cow resulted in less calves lying and more walking, than when no cow was present. The authors concluded that trainer cows did not improve calf health, time spent at the feed bunk or performance of newly weaned calves.

Male broiler breeder fowl display high levels of aggression towards females.

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Commercial broiler breeder males are reported to display high levels of aggression, often injuring and sometimes killing females. Aggression toward females by mature male domestic fowl is rare and may be regarded as aberrant behaviour. The objective of this study was to determine the effects of genetic strain and feed restriction on the sexual and aggressive behaviour of male domestic fowl. Behaviour of 3 genetic strains (two broiler breeder strains and one commercial laying strain) on two feeding regimens (one restricted and one fed ad libitum) between 25 and 37 d of age was compared in this experiment. At 22 week of age, pairs of same-strain males were penned with 20 females of a broiler breeder strain. Behaviour was sampled from each pen for six 10-min periods during weeks 25, 27, 29, 33 and 37. Broiler breeder males displayed significantly more male-to-male and male-to-female aggression than laying strain males. Broiler breeder males chased females, forced more copulations and displayed little courtship behaviour compared with laying strain males. There were no behavioural differences between broiler breeder strains. It was expected that feed restriction would result in increased aggression. However, males fed ad libitum displayed the most male-to-male and male-to-female aggression. Sexual behaviour was not affected by feeding regimen. In conclusion, broiler breeder males display aberrant sexual behaviour and extremely high levels of aggression, which are associated with genetic differences, not feed restriction