Impact of experimentally induced bacterial chondronecrosis with osteomyelitis (BCO) lameness on health, stress, and leg health parameters in broilers.

Stress and lameness negatively affect the health, production, and welfare of broilers. Bacterial chondronecrosis with osteomyelitis (BCO) is a leading cause of stress and lameness in commercial broilers. External changes in skin temperature related to changes in blood flow can be detected with infrared thermography (IRT), offering a noninvasive tool to assess the health of animals. This study compared physiological and noninvasive measures of stress and lameness in clinically healthy and lame male broiler chickens between 25 and 56 d. Birds were raised in pens within separate environmental chambers containing either litter flooring (sound) or wire flooring, with the latter established to induce BCO lameness (lame). Physiological and noninvasive measures of stress and lameness were collected: body weight, (BW), relative bursa weight, core body temperature, corticosterone (CORT) concentrations in serum and feathers, surface temperatures of the head (eye and beak) and leg (hock, shank, and foot) regions by infrared thermography (IRT), leg blood oxygen saturation (leg O2), and BCO lesion severity scores of tibial head necrosis (THN) and femoral head necrosis (FHN). Lame birds exhibited greater FHN and THN lesion severities, core body temperatures, and serum CORT (P < 0.05), but had lower BW, relative bursa weight, leg O2, and IRT surface temperatures of the beak, hock, shank, and foot compared with sound birds (P < 0.05). The difference in THN lesion severity between sound and lame birds decreased with age. Linear relationships between leg O2 with IRT leg surface temperatures were positive and negative between leg O2 with BCO lesion severity (P < 0.05). There were negative correlations between serum CORT with hock, shank and foot temperatures (P < 0.001), indicating that BCO is stressful. These results indicate that birds lame from BCO are stressed, have reduced oxygen saturation of blood in their legs, and that IRT surface temperatures can be used as noninvasive indicators of stress and lameness in broilers.

Broiler stress responses to light intensity, flooring type, and leg weakness as assessed by heterophil-to-lymphocyte ratios, serum corticosterone, infrared thermography, and latency to lie.

Stress and leg weakness are detrimental to broiler production, health, and welfare. Traditional methods to evaluate stress may be stressful to the bird because they are invasive and require handling and restraint. Two studies examined the effects of light intensity and flooring on the following in broilers: 1) traditional methods for assessing stress using heterophil-to-lymphocyte ratios and serum corticosterone (CORT) concentrations, 2) noninvasive measures of stress from infrared thermography (IRT) eye and beak surface temperatures, and 3) latency-to-lie (LTL) test times of birds tested individually and in groups of 5. Day-of-hatch male broiler chicks were placed into 6 pens (N = 120 chicks/pen). At 1 wk, pens were allocated to 3 light intensity treatments (2, 5, or 10 lux). At 4 wk, half of the birds from each pen were moved to a pen with wire flooring and the same light intensity. At 1, 4, 5, and 8 wk, blood samples were collected and IRT images of the heads of 5 clinically healthy broilers from each pen were captured. In study 2, IRT images of the heads of birds that became lame in the wire flooring pens were taken. There were no treatment effects on the LTL times of birds tested in groups or individually (P > 0.05). On day 56 in study 1, birds on wire flooring had elevated heterophil-to-lymphocyte ratios and CORT concentrations (P ≤ 0.002) and depressed IRT eye and beak temperatures (P < 0.0001). In both studies, there were negative correlations between CORT concentrations and IRT beak surface temperatures (P < 0.05). Lame birds had lower IRT eye and beak surface temperatures than sound birds (P ≤ 0.004), and the IRT beak surface temperatures of lame birds were lower than their eye surface temperatures (P = 0.004) in study 2. These studies indicate that the IRT surface temperatures of the eye, and more distinctly of the beak, can be used as sensitive noninvasive indicators of stress.

Effect of transportation and shackling on plasma concentrations of corticosterone and heterophil to lymphocyte ratios in market weight male turkeys in a commercial operation.

There is limited information on the effects of stress and/or physiological manipulation on either plasma concentrations of corticosterone (CORT) and/or heterophil: lymphocyte (H : L) ratios in turkeys. The present studies examine the effects of catching/transportation/lairage in a holding shed and shackling on plasma concentrations of CORT and H : L ratios in male market weight turkeys. Plasma concentrations of CORT were increased after transportation and lairage but not further elevated by shackling, irrespective of its duration up to 240 s. In one study, there were increased H : L ratios following catching/placing birds into transportation cages/transportation/lairage. In one study, H : L ratios declined following shackling. It is concluded that while moving turkeys from the farm to immediately before the shackling line is stressful, shackling for up to 4 min was not perceived as more stressful in turkeys. There were also differences between farms/houses for both plasma concentrations of CORT and H : L ratios.

Effects of putative stressors and adrenocorticotropic hormone on plasma concentrations of corticosterone in market-weight male turkeys.

There is limited information on the effects of stress and/or physiological manipulation on plasma concentrations of corticosterone (CORT) in turkeys. Under basal conditions, there was evidence for episodic release of CORT in turkeys. The present studies determine the effects of handling, herding, herding, the administration of Escherichia coli endotoxin, and challenge with turkey adrenocorticotropic hormone (ACTH) on plasma concentrations of CORT in market-weight male turkeys. Plasma concentrations of CORT were increased after challenge with turkey ACTH, handling together with saline injection or herding (moving birds from one pen to another). There were no effects on plasma concentrations of CORT of the following putative stressors: handling per se, endotoxin challenge, or of placing in an inverted position on simulated shackles.

The utility of infrared thermography for evaluating lameness attributable to bacterial chondronecrosis with osteomyelitis.

Bacterial chondronecrosis with osteomyelitis (BCO) is a leading cause of lameness in broilers. Infrared thermography (IRT) is a noninvasive technique for measuring infrared radiation from an object and can be used to evaluate clinical health. Two replicated studies compared the effect of light intensity on broilers grown on a wire flooring model that experimentally increased their susceptibility to and incidence of BCO lameness. Day-of-hatch male broiler chickens were placed into 6 pens on wood shavings litter, and at 1 wk one of 3 light intensity treatments (2, 5, or 10 lux) was allotted. At 4 wk half of the population from each pen was moved to a pen with wire flooring and the same light intensity. At 1, 4, 5, and 8 wk, an IRT image of the legs of 5 clinically healthy broilers from each pen was taken. The right and left proximal femora and tibiae of sound and lame broilers were scored for femoral head necrosis (FHN) and tibial head necrosis (THN) lesion severity. There were minimal effects of light intensity and flooring. In Study 1, but not Study 2, broilers on wire flooring weighed less on day 38 (P = 0.007) and days 57 to 58 (P = 0.003) compared to those on litter. The proportion of broilers that became lame on wire flooring was 52% in Study 1 and 14% in Study 2. The proportion of sound broilers from litter and wire flooring pens with subclinical signs of BCO in their right or left proximal growth plates was over 45% for FHN and 92% for THN, and lame broilers had more severe (P < 0.0001) FHN and THN compared to sound broilers. IRT surface temperatures of the hock joint, shank, and foot were consistently lower (P < 0.0001) in broilers that became lame when compared to sound. Therefore, IRT surface temperatures of broiler leg regions may be useful for detecting lesions attributed to BCO.

An evaluation of methods for measuring stress in broiler chickens.

There are potential advantages for using noninvasive methods instead of conventional approaches for measuring corticosterone (CORT) as a metric of stress. Two studies compared blood heterophil: lymphocyte (H:L) ratios, serum CORT, cecal content CORT (Study 1), colon content CORT (Study 2), and feather CORT concentrations for broiler chicks receiving drinking water with or without added CORT. On day 28, male broilers (N = 140) were provided tap water (Control group) or water containing 20 mg/L of CORT (CORT group) for up to 72 h. Body weight (BW), blood, feather, cecal, and colon content samples were collected from 10 birds from each treatment group at 0, 6, 12, 24, 30, 48, and 72 h. Data were analyzed with a JMP Pro ANOVA. Mean comparisons were analyzed on significant treatment effects using post hoc t-tests to compare control and CORT measures within each sampling time point. Pearson's pairwise correlations for all data were performed. A treatment by time interaction affected all measures in both studies. In both studies, CORT treatment reduced body weight and increased H:L ratios at later time points. In study 1 cecal content CORT concentrations were elevated with CORT treatment after 24 h, whereas in study 2 colon content CORT concentrations were elevated after 6 h. CORT treatment increased body and primary feather CORT and primary feather CORT increased with time in control groups in both studies. Serum CORT exhibited the lowest variability compared with all other sample sources used for determining CORT. Estimates of CORT by different methods were positively correlated. These results indicate that serum CORT concentrations most reliably reflect the CORT status of broilers, and that feather CORT concentrations demonstrated potential for estimating stress in broilers.

Values, trust and science - building trust in today's food system in an era of radical transparency.

Public concern exists globally about the food system and both the practices and the intensification of animal agriculture. Examples are presented of public opinion in North America, the European Union, and the People's Republic of China. Negative perceptions increase with distance from production agriculture. Even animal science faculty members do not uniformly support present production practices. Public trust in the food system is based on consumers' or public confidence (shared values based on corporate and institutional social responsibility or their fiduciary responsibility), competence of the people or groups providing the information and the influence of others (e.g., friends and family). Producer or company discussion of issues has focused on competency and "the science" when confidence is markedly more important to consumers and more effective. It is argued that the food system largely escapes regulation by federal and state governments by a social license based on public confidence. However, a tipping point(s) exists such that a crisis could greatly diminish public confidence and end the social license and bring with it increases in regulation. Advocacy for production agriculture (poultry and livestock) needs to incorporate recognition of the need to reaffirm the public's trust, assuring shared values together with an emphasis on good science.

Behavioural, brain and cardiac responses to hypobaric hypoxia in broiler chickens.

A novel approach to pre-slaughter stunning of chickens has been developed in which birds are rendered unconscious by progressive hypobaric hypoxia. Termed Low Atmospheric Pressure Stunning (LAPS), this approach involves application of gradual decompression lasting 280s according to a prescribed curve. We examined responses to LAPS by recording behaviour, electroencephalogram (EEG) and electrocardiogram (ECG) in individual male chickens, and interpreted these with regard to the welfare impact of the process. We also examined the effect of two temperature adjusted pressure curves on these responses. Broiler chickens were exposed to LAPS in 30 triplets (16 and 14 triplets assigned to each pressure curve). In each triplet, one bird was instrumented for recording of EEG and ECG while the behaviour of all three birds was observed. Birds showed a consistent sequence of behaviours during LAPS (ataxia, loss of posture, clonic convulsions and motionless) which were observed in all birds. Leg paddling, tonic convulsions, slow wing flapping, mandibulation, head shaking, open bill breathing, deep inhalation, jumping and vocalisation were observed in a proportion of birds. Spectral analysis of EEG responses at 2s intervals throughout LAPS revealed progressive decreases in median frequency at the same time as corresponding progressive increases in total power, followed later by decreases in total power as all birds exhibited isoelectric EEG and died. There was a very pronounced increase in total power at 50-60s into the LAPS cycle, which corresponded to dominance of the signal by high amplitude slow waves, indicating loss of consciousness. Slow wave EEG was seen early in the LAPS process, before behavioural evidence of loss of consciousness such as ataxia and loss of posture, almost certainly due to the fact that it was completely dark in the LAPS chamber. ECG recordings showed a pronounced bradycardia (starting on average 49.6s into LAPS), often associated with arrhythmia, until around 60s into LAPS when heart rate levelled off. There was a good correlation between behavioural, EEG and cardiac measures in relation to loss of consciousness which collectively provide a loss of consciousness estimate of around 60s. There were some effects of temperature adjusted pressure curves on behavioural latencies and ECG responses, but in general responses were consistent and very similar to those reported in previous research on controlled atmosphere stunning with inert gases. The results suggest that the process is humane (slaughter without avoidable fear, anxiety, pain, suffering and distress). In particular, the maintenance of slow wave EEG patterns in the early part of LAPS (while birds are still conscious) is strongly suggestive that LAPS is non-aversive, since we would expect this to be interrupted by pain or discomfort.

Symposium: Animal welfare challenges for today and tomorrow.

The increasing separation of the public from production agriculture means there is often a lack of knowledge among consumers about current production practices and a perception that increased productivity and economic efficiency are necessarily associated with a decline in animal welfare. A symposium was organized to present information about animal welfare issues and the challenges they pose for both scientists and the poultry and allied industries. Companion papers provide information about understanding public attitudes and physiological/immunological approaches to welfare assessment, while this paper outlines current and future challenges to egg and meat production and industry responses to those challenges. For broiler chickens, increases in growth rate result in corollary increases in metabolic heat generation and water consumption, leading to the need for continuing improvements in housing, ventilation, and litter management. Stocking densities, lighting programs, muscle myopathies, and use of antibiotics are also areas that require research attention. In the layer industry, the key challenge is housing, with the industry undergoing a shift from conventional cage housing to alternatives like enriched colonies or cage-free. While these alternative systems have hen welfare advantages, there are also welfare disadvantages that require the development of mitigation strategies, and it is also essential to address associated issues including economic, environmental, egg safety, and worker health impacts. Concerns on the horizon include euthanasia of surplus male chicks and spent hens as well as beak-trimming. The humaneness of slaughter methods is an important welfare and consumer confidence issue, and the current regulations for poultry slaughter in the USA are discussed and compared to those for livestock. The poultry and allied industries, including retailers, are responding to these concerns by consulting with experts, developing science-based animal care standards and auditing programs, strengthening training and oversight programs, promoting research, and improving communication channels. In future, intensifying multi-disciplinary research efforts and developing mechanisms to improve communication between scientists and stakeholders, including the public, will be critical to addressing these issues.