Simplifying the Welfare Quality® assessment protocol for broiler chicken welfare.

Welfare Quality(®) (WQ) assessment protocols place the emphasis on animal-based measures as an indicator for animal welfare. Stakeholders, however, emphasize that a reduction in the time taken to complete the protocol is essential to improve practical applicability. We studied the potential for reduction in time to complete the WQ broiler assessment protocol and present some modifications to the protocol correcting a few errors in the original calculations. Data was used from 180 flocks assessed on-farm and 150 flocks assessed at the slaughter plant. Correlations between variables were calculated, and where correlation was moderate, meaningful and promising (in terms of time reduction), simplification was considered using one variable predicted from another variable. Correlation analysis revealed a promising correlation between severe hock burn and gait scores on-farm. Therefore, prediction of gait scores using hock burn scores was studied further as a possible simplification strategy (strategy 1). Measurements of footpad dermatitis, hock burn, cleanliness and gait score on-farm correlated moderately to highly with slaughter plant measurements of footpad dermatitis and/or hock burn, supporting substitution of on-farm measurements with slaughter plant data. A simplification analysis was performed using footpad dermatitis, hock burn, cleanliness and gait scores measured on-farm predicted from slaughter plant measurements of footpad dermatitis and hock burn (strategy 2). Simplification strategies were compared with the full assessment protocol. Close agreement was found between the full protocol and both simplification strategies although large confidence intervals were found for specificity of the simplified models. It is concluded that the proposed simplification strategies are encouraging; strategy 1 can reduce the time to complete the on-farm assessment by ~1 h (25% to 33% reduction) and strategy 2 can reduce on-farm assessment time by ~2 h (50% to 67% reduction). Both simplification strategies should, however, be validated further, and tested on farms with a wide distribution across the different welfare categories of WQ.

Cone restraining and head-only electrical stunning in broilers: effects on physiological responses and meat quality.

Two experiments were conducted to evaluate a new electrical stunning system for broilers. The objective of the first experiment was to evaluate the behavioral, neural, and physiological responses of 27 broilers after head-only electrical stunning while their bodies were restrained in cone-shaped holders. In the second experiment, quality of meat from 30 broilers after head-only electrical stunning in a cone-shaped restrainer was compared with that from 30 broilers stunned in a conventional water bath. Broilers were restrained in the cone with their heads positioned to facilitate a correct stun, followed by a neck cut by hand. After stunning, each broiler displayed a tonic phase, followed by minimal brain activity during bleeding. On average, heart rate was 258 ± 51 beats/min before stunning. The heart was observed to malfunction after cutting. According to the correlation dimension analyses, the score remained low. Within a confidence limit of 95%, taking into account the number of birds with a reliable electroencephalogram (n = 27), the chance of an effective stun and exsanguination with all broilers lies between 0.90 and 1.00 using a sinusoidal AC current of 264 ± 29 mA (∼130 V). After a brief learning period, operators were able to easily position the broilers in the cone in a commercial setting. The pH after chilling was 0.5 units lower (P < 0.05) in the head-only stunned group compared with the group stunned in a conventional water bath. After head-only stunning, 60% of breast fillets showed no blood splashes and 3% showed severe blood splashes compared with 20 and 27% after conventional water bath stunning. No differences in temperature and color were observed between the 2 groups. It is concluded that broilers could be restrained in a cone, followed by correct head-only stunning, neck-cutting, and unconscious shackling afterward under laboratory and commercial slaughterhouse conditions. When this procedure was used, meat quality was better compared with broilers stunned in the conventional water bath.

The effect of reduced loading density on pig welfare during long distance transport.

Transport of animals is a stressful procedure often resulting in significant losses for the slaughter plant. This study aimed to determine whether or not pigs would benefit from a loading density (low density (LD)) (179 kg/m2) below the normal EU standard loading density (normal density (ND)) (235 kg/m2). Eight similar, 550-km-long road journeys, were followed in which fattening pigs were transported across Germany from farm to slaughter plant. During each journey all pigs were transported at LD (n=4) or ND (n=4). Twelve female pigs per journey (total n=96) were randomly selected for measurement and monitoring of body temperature, behaviour, heart rate and blood parameters. Throughout the journeys, LD pigs displayed more resting behaviour than ND pigs. Average body temperature was lower (P<0.05) for pigs transported at LD (38.0±0.07°C) than those transported at ND (38.3±0.06°C). During loading heart rate increased in both ND and LD pigs and declined after the vehicle had been closed before departure but remained slightly elevated in ND pigs. Pigs transported at ND displayed signs of stress (elevated HR and body temperatures) during the drivers' break. Blood parameters were only slightly (not significant) effected by loading density. Results indicate that pigs are more capable of adapting to long (550 km) transport conditions when loaded at a density below the present EU requirement.

Physiological and behavioral responses of poultry exposed to gas-filled high expansion foam.

Disease control measures require poultry to be killed on farms to minimize the risk of disease being transmitted to other poultry and, in some cases, to protect public health. We assessed the welfare implications for poultry of the use of high-expansion gas-filled foam as a potentially humane, emergency killing method. In laboratory trials, broiler chickens, adult laying hens, ducks, and turkeys were exposed to air-, N2-, or CO2-filled high expansion foam (expansion ratio 300:1) under standardized conditions. Birds were equipped with sensors to measure cardiac and brain activity, and measurements of oxygen concentration in the foam were carried out. Initial behavioral responses to foam were not pronounced but included headshakes and brief bouts of wing flapping. Both N2- and CO2-filled foam rapidly induced ataxia/loss of posture and vigorous wing flapping in all species, characteristic of anoxic death. Immersion in air-filled, high expansion foam had little effect on physiology or behavior. Physiological responses to both N2- and CO2-filled foam were characterized by a pronounced bradyarrythymia and a series of consistent changes in the appearance of the electroencephalogram. These were used to determine an unequivocal time to loss of consciousness in relation to submersion. Mean time to loss of consciousness was 30 s in hens and 18 s in broilers exposed to N2-filled foam, and 16 s in broilers, 1 s in ducks, and 15 s in turkeys exposed to CO2-filled foam. Euthanasia achieved with anoxic foam was particularly rapid, which is explained by the very low oxygen concentrations (below 1%) inside the foam. Physiological observations and postmortem examination showed that the mode of action of high expansion, gas-filled foam is anoxia, not occlusion of the airway. These trials provide proof-of-principle that submersion in gas-filled, high expansion foam provides a rapid and highly effective method of euthanasia, which may have potential to provide humane emergency killing or routine depopulation.

Multistage carbon dioxide gas stunning of broilers.

The stunning quality of animals for slaughter remains under constant scrutiny. In response to previous research showing low stunning efficiency in poultry, the conventional water bath will be phased out in the Netherlands. Presently, the main practical alternative to water bath stunning of poultry is a 2-phased gas stunning method. Gas stunning methods are recognized by governments and animal welfare organizations across Europe. In this study, 3 sets of experiments were conducted on gas stunning methods using CO(2) in 2 phases. Two methods were examined to identify potential effects on bird behavior and investigate their practical implications: a 5-stage incremental CO(2) scheme lasting 6 min (treatment 1) and a 4-stage incremental CO(2) scheme lasting 4 min (treatment 2). The onset and duration of unconsciousness were specifically tested in experiment 2 by using 25 birds equipped with electrodes monitoring brain and heart activity. Behavioral responses were observed on 15 non-instrument-monitored birds kept in the same cages at that time. Results in all 3 sets of the experiments showed that multistage gas stunning was stable and consistent, and increases in CO(2) concentrations were rapid and reliable. Ambient temperatures and RH of the air remained within acceptable levels at all times. Induction of unconsciousness occurred below 40% CO(2) and did not significantly differ between treatments. Conscious birds were never exposed to high CO(2) concentrations (>40% CO(2)), yet some birds showed signs of distress (e.g., head shaking, wing flapping) before losing consciousness. Discomfort experienced during exposure to low (<40%) CO(2) concentrations compares favorably with the experiences of handling, tilting, and or shackling of conscious birds when using alternative stunning methods, implying that multistage gas stunning has distinct advantages for bird welfare. Compared with the multibird water bath system, this method provides an opportunity to guarantee that all birds are properly stunned. The risk of convulsions, which was higher with treatment 2, leading to possible injuries, indicates a preference for the 5-stage treatment.

Footpad dermatitis in Dutch broiler flocks: prevalence and factors of influence.

In some European countries, footpad dermatitis (FPD) is measured as an indicator of broiler welfare. Prevalence and seasonal variation of FPD was determined within broiler flocks (fast-growing breeds) in the Netherlands. Samples were taken from 386 Dutch flocks at 8 slaughterhouses during a period of one year. Prevalence of footpad dermatitis was related to background information gathered using a food chain certification scheme to identify possible factors of influence. On average, 35.5% of the broilers had no lesions, whereas 26.1% and 38.4% had mild or severe lesions, respectively. Season, age, thinning of flocks, slaughter age, breed, slaughterhouse, and the interaction between thinning and slaughter age significantly affected severity of FPD. Peak flock FPD scores occurred in flocks where 1-d-old chicks were placed in March and December, whereas flocks placed in warm months, between June and August, displayed lower flock FPD scores. Generally, birds sent to slaughter when thinning a flock displayed less severe FPD than birds from completely depopulated flocks. Severity of FPD decreased with age. Because poultry farmer, hatchery, veterinary practice, and feed manufacturer were included in the model as random factors, it was only possible to assess their contribution relative to each other. The broiler farmer had the largest contribution. Also, a large contribution was found for hatchery, perhaps indicating that broiler quality is important. No relationship was observed between FPD and mortality. Across farms, less severe FPD was observed on farms using antibiotics. However, within farms, FPD was more common in flocks where antibiotics had been used compared with flocks that did not require antibiotic treatment. In conclusion, footpad dermatitis was frequently observed in Dutch fast-growing broiler flocks, and many factors had significant effects on severity of FPD, such as breed, thinning of flocks, age at slaughter, slaughter plant, and hatchery.

Head-cloaca controlled current stunning: assessment of brain and heart activity and meat quality.

1. Behavioural and neural responses of 65 broilers to head-to-cloaca electrical stunning were evaluated and meat quality was assessed on two groups of 25 broilers stunned either head to cloaca, or in a conventional water bath method. 2. On the EEG recordings, a general epileptiform insult was observed when applying a current of 100 mA (100 Hz) or 70 mA (70 Hz) for 1·5 s. This general epileptiform insult shows a tonic, clonic and exhaustion phase followed by spikes of alpha, beta, theta and delta waves with duration of on average 34 ± 12 s and 39 ± 23 s respectively. These birds may have been unconscious for 20 s or longer, according to the correlation dimension analyses. 3. The heart rate decreased significantly (P < 0·05) after stunning and recovered after 60 s. 4. Within a confidence limit of 95%, taking into account the number of animals with a reliable EEG, the chance of an effective stun of all broilers lies between 0·9 and 1·0 with a current of 70 mA (100 Hz for 1·5 s; n = 28) and with 100 mA (100 Hz for 1·5 s; n = 27). 5. The shear force of breast fillets was slightly lower (P < 0·01) 4 d post mortem compared with the conventional water bath stunned group (set at 100 mA, 100 Hz for 10 s). The percentage of fillets and legs without blood splashes was higher, and the percentage with severe blood splashes lower-to-none, for carcases stunned head-cloaca. 6. It can be concluded that broilers are effectively stunned with the head-cloaca method by using a controlled current of 70 mA or 100 mA for 1·5 s. The fillets and legs of bird stunned head-cloaca showed fewer blood splashes in the muscles compared with birds stunned in a conventional water bath.

Restraining and neck cutting or stunning and neck cutting of veal calves.

Brain and heart activities were measured in 31 veal calves during restraining and rotating followed by neck cutting with or without stunning to evaluate welfare. After neck cutting correlation dimension analyses and %power of EEG beta wave fraction decreased gradually to lower values resulting in an induction of unconsciousness lasting on average 80s. Corneal reflex response ceased 135±57s after neck cutting. The CD scores and the %power of beta waves fell immediately after post-cut captive bolt and pre-cut electrical stunning to levels indicating unconsciousness. Heart rate in lairage increased upon entrance to the restrainer and again after rotation, heart rate variability decreased. Rotating the restrainer 90°, 120° or 180° compromised veal calf welfare and should be avoided. It is recommended to use post-cut captive bolt stunning or pre-cut electrical stunning inducing immediate unconsciousness.

Evaluation of head-only electrical stunning for practical application: assessment of neural and meat quality parameters.

Behavioral and neural responses of 47 broilers to head-only single-bird electrical stunning were evaluated using cone-shaped restrainers in which the broilers were suspended by their feet. Meat quality assessment was performed on 2 groups of 25 broilers stunned using the head-only method or a conventional water bath method. Hemorrhages were quantified by a visual grading system. On electroencephalogram recordings, a general epileptiform insult was observed when a set current of at least 190 mA (~100 V, 50 Hz) was applied for a duration of 0.5, 3, or 5 s. This insult showed a tonic phase, followed by a clonic phase and an exhaustion phase, after which the birds recovered. On the basis of visual observation, these birds may have been unconscious for approximately 30, 44, or 65 s. According to correlation dimension analysis scores, these durations were 18, 12, and 16 s, respectively. Within a confidence limit of 95%, taking into account the number of birds with a reliable electroencephalogram, the chance of an effective stun lies between 0.95 and 1.00 with an average current of 190 ± 30 mA. After stunning, the electrocardiogram revealed fibrillation. The heart rate decreased significantly (P < 0.05) after stunning but recovered thereafter. The pH after chilling was (P < 0.05) lower in the group stunned head only compared with the water bath group. The percentages of fillets free of blood splashes were 80% in carcasses of head-only-stunned birds and 16% in carcasses from broilers stunned in the commercial water bath. It was concluded that broilers were insensible and unconscious after head-only electrical stunning using pin-electrodes. Because of the risk that broilers can rapidly regain consciousness after stunning, cutting the neck immediately after stunning is recommended. It is also recommended that the head-only equipment be developed further for practical application and commercial use.

Animal welfare concerns during the use of the water bath for stunning broilers, hens, and ducks.

European legislation demands that slaughter animals, including poultry, be rendered immediately unconscious and insensible until death occurs through blood loss at slaughter. This study addressed requirements for stunner settings (i.e., voltage, wave oscillation frequency) and response parameters (i.e., applied current, behavior) affecting effective water bath stunning. An inventory of current electrical stunning practice was performed in 10 slaughterhouses in the Netherlands. Thereafter, measurements were performed using a single-bird water bath to examine the effects of stunner settings based on the average technical settings observed in the slaughterhouses. Responses were recorded at 50, 400, and 1,000 Hz on broilers and hens and at 50 and 400 Hz on ducks under controlled laboratory conditions. Effects of voltage settings (broilers: 100 to 400 V; hens: 150 to 300 V; ducks: 150 to 400 V) on current levels (broilers: 45 to 444 mA; hens: 40 to 219 mA; ducks: 64 to 362 mA) and consciousness (response to pain stimulus) were recorded immediately after stunning. Brain and heart activity was monitored using electroencephalogram and electrocardiogram technology. Results show that effective stunning using the conventional water bath almost exclusively produces blood splashing in broilers. Effective stunning current levels did not differ significantly between broilers, hens, and ducks effectively stunned hens tended to require lower currents. Effective stuns at higher frequencies resulted in higher currents. Similar input voltage (V) levels (within and between bird type) resulted in significant variation (P < 0.001) in current levels (mA) required for an effective stun, indicating variability in electrical impedance between individual birds. Body weight and bird type did not affect the probability of an effective stun. Multi-bird water bath usage does not ensure effective stunning and technical adjustments can result in detrimental effects on meat quality. Future legislation should consider wave form, relationships between frequency and current allowing for individual impedance variation and effects on meat quality while safeguarding animal welfare.

Effect of maize starch concentration in the diet on starch and cell wall digestion in the dairy cow.

An in vivo experiment was performed to determine the effect of level of maize starch in the diet on digestion and site of digestion of organic matter, starch and neutral detergent fibre (NDF). In a repeated change-over design experiment, three cows fitted with a rumen cannula and T-piece cannulae in duodenum and ileum received a low-starch (12% of ration dry matter) and a high-starch (33% of ration dry matter) diet. Starch level was increased by exchanging dried sugar beet pulp by ground maize. After a 2-week adaptation period, feed intake, rumen fermentation parameters (in vivo and in situ), intestinal flows, faecal excretion of organic matter, starch and NDF were estimated. When the high-starch diet was fed, dry matter intake was higher (19.0 kg/day vs. 17.8 kg/day), and total tract digestibility of organic matter, starch and NDF was lower when the low-starch diet was fed. Maize starch concentration had no significant effect on rumen pH and volatile fatty acid concentration nor on the site of digestion of organic matter and starch and rate of passage of ytterbium-labelled forage. On the high-starch diet, an extra 1.3 kg of maize starch was supplied at the duodenum in relation to the low-starch diet, but only an extra 0.3 kg of starch was digested in the small intestine. Digestion of NDF was only apparent in the rumen and was lower on the high-starch diet than on the low-starch diet, mainly attributed to the reduction in sugar beet pulp in the high-starch diet. It was concluded that without the correction for the reduction in NDF digestion in the rumen, the extra supply of glucogenic (glucose and propionic acid) and ketogenic nutrients (acetic and butyric acid) by supplemented starch will be overestimated. The mechanisms responsible for these effects need to be addressed in feed evaluation.

Site and extent of starch degradation in the dairy cow - a comparison between in vivo, in situ and in vitro measurements.

Prediction of the supply of glycogenic precursors to dairy cows and the site of degradation of wheat, maize and potato starch (PS) were determined in an in vivo experiment and the results were compared with data obtained from experiments involving in situ nylon bag and in vitro gas production techniques. In a Latin square design experiment four lactating dairy cows fitted with a rumen cannula and T-piece cannulae in the duodenum and terminal ileum, received either a low-starch control diet or diets in which sugar beet pulp in the concentrate mixture had been replaced by wheat, maize or PS. Starch from the different sources was almost completely degraded in the total gastrointestinal tract. For all starches, the rumen was the main site of degradation in vivo. No digestion of PS in the small intestine was observed. In situ results suggested that 14% of wheat starch (WS), 47% of maize starch and 34% of PS escaped rumen fermentation. According to the gas production technique WS ferments quickest and potato slowest. PS had a low degradability during the first 8 (gas production) to 11 (in situ) h. However, according to both in vitro and in vivo measurements rumen degradability of PS was high. The results suggest that in situ and in vitro techniques should be performed in animals that have adapted to starch source to provide a more accurate simulation of the in vivo situation.