Prevalence and factors associated with it, of birds dead on arrival at the slaughterhouse and other rejection conditions in broiler chickens.

1. Standardised data on husbandry were recorded for a flock of birds in one house on each of 150 broiler farms in the UK during the 4 d prior to slaughter. 2. For each flock, the incidence of birds found dead on arrival (DoAs) and the Meat Hygiene Service carcase rejection records were recorded at the slaughterhouse. 3. The mean percentage of birds in each flock found DoA was 0.12% (range 0-0.64%) and the mean percentage of Total Carcase Rejects (TCRs) for each flock was 1.23% (range 0.07-5.51%). 4. A general linear model was developed to examine factors associated with flock percentage DoAs. Assuming a linear relationship, all other factors remaining the same, a one percentage point (PP) increase in small/emaciated birds will result in a 0.155 PP increase in DoAs and a 1 PP increase in wheat in diet 4 will result in a 0.003 PP decrease. An increase by one in the total number of vaccines administered will cause a 0.029 PP decrease in DoAs, a 1 g increase in live weight at slaughter will be associated with a 0.000043 PP increase and a 1 PP increase in mortality on farm would be associated with a 0.000044 PP increase. A 1 PP increase in Ross birds decreases DoAs by 0.0004 PPS: there is also a seasonal effect. 5. The model developed for flock percentage TCRs found that a 1 PP increase in wheat in diet 3 will result in a 0.052 PP decrease in TCRs and a 1 PP increase in Ross birds will cause a 0.009 PP decrease. A 1 PP increase in birds culled on farm will be associated with a 0.03 PP increase in TCRs and the diagnosis of disease during the flock cycle increases TCRs by 0.397 PPs. A one day increase in age at slaughter will result in a 0.046 PP increase in TCRs.

Interactions between the beta-adrenergic agonist salbutamol and genotype on meat quality in pigs.

Salbutamol (2.7 ppm) fed to pigs between weaning and slaughter increased ADG (5%), dressing percentage (2%) and cross-sectional area of the longissimus (LD) muscle (14%). In fatter, White-line-sired pigs, but not in leaner, Meat-line-sired animals, it reduced backfat thickness (25%). Liver weight and glycogen concentration also were decreased. In neither genotype were there effects of Salbutamol on pH45, drip loss or reflectance value of the LD, but ultimate pH was elevated in semimembranosus (SM), adductor (AD) and supraspinatus (SS) muscles, resulting in reduced color saturation values. Total muscle heme pigment concentrations were reduced by 10 (SS) to 19% (LD and SM) and the intramuscular fat concentration of the AD, but not the LD, was reduced by 21%. Treated pigs had LD and SM muscles that when measured instrumentally were 15 and 8% tougher, respectively, after cooking, but the texture of the SS was not significantly altered by treatment. Salbutamol increased plasma lactate and creatine phosphokinase (CPK) concentrations. Compared with White-line-sired animals, Meat-line-sired pigs had a higher dressing percentage (2%) and LD muscles with larger cross-sectional area (13%). They also had higher circulating CPK levels.

The effects of the beta-adrenergic agonist salbutamol on meat quality in pigs.

The beta-adrenergic agonist Salbutamol was administered to pigs at 3 ppm in the feed between weaning and slaughter at 85 kg. Growth rate was not affected by Salbutamol. Treated pigs had a higher dressing percentage (2.6%) and produced carcasses that were less fat (17%) and had longissimus (LD) muscles of larger (11%) cross-sectional area. They also had smaller livers that contained less glycogen. The thinner backfat in treated animals was less firm and tended to separate from the underlying lean. However, these changes were attributable solely to the reduced fatness and there was no direct effect of Salbutamol. There were no differences in pH 45 min postmortem, percentage drip loss during storage or reflectance value of the LD between the two groups, indicating no greater propensity for Salbutamol-treated pigs to develop pale, soft, exudative muscle. However, treated pigs had higher final pH values in the muscles; this was reflected in slightly reduced hue and saturation values. These results suggest that the propensity of the pigs to develop dark, firm, dry meat was slightly increased. Salbutamol-treated pigs produced LD muscles that were slightly tougher (22%), had reduced concentration of heme pigments in the muscle, reduced plasma glucose and increased plasma creatine phosphokinase activity. Salbutamol improved lean meat yield but slightly increased the potential to produce dark, firm, dry meat and reduced tenderness.

A note on the influence of rearing environment on meat quality in pigs.

Pigs of stress-resistant and stress-susceptible breeds were reared either under intensive conditions in bare concrete pens or extensively under environmentally enriched conditions in an outside paddock. They were slaughtered at either 60 or 90 kg live weight. Rearing environment had no effect on the ability of the pigs to respond to the stress of preslaughter handling based on measurements of adrenal ascorbic acid and plasma cortisol. Neither did it influence initial or ultimate pH or the water holding capacity of the meat. Pigs reared outside had thinner backfat and slightly darker meat. The latter was not attributable to differences in haem pigment concentration. Overall, differences due to rearing environment were slight and not commercially important.

Eating quality of meat from pigs given the beta-adrenergic agonist salbutamol.

Meat from pigs given the beta-adrenergic agonist Salbutamol was assessed by a trained taste panel. Overall, there were no significant effects of Salbutamol on panel scores for pork flavour, foreign flavour or overall acceptability. Although the differences were also not significant, meat from treated pigs was rated slightly tougher (P = 0·10) but more juicy (P = 0·14) than that from untreated animals. This concurred with higher instrumental values for toughness although the correlation between taste panel and instrumental texture measurements was low (r = 0·36, P < 0·001).

The thickness and quality of backfat in various pig breeds and their relationship to intramuscular fat and the setting of joints from the carcasses.

The characteristics of backfat were measured in carcasses from 233 pigs representing eleven breeds. Animals were fed ad libitum and killed at an average live weight of 62 kg. In breeds in which the backfat was thicker it was also firmer and contained less water. In leaner breeds there was reduced cohesiveness of fat and muscle components of the loin joint so that the fat separated more easily from the underlying lean. This contributed to joints which were subjectively assessed as less firm and well set. Fatter breeds tended to have Longissimus muscles which contained more intramuscular fat. However, the relationship between muscle fat and carcass fat was poor suggesting that, if it was thought desirable to select for increased intramuscular fat in the interests of meat palatability, then this could be achieved without making carcasses undesirably fat. Differences in fat characteristics between breeds were apparently largely attributable to differences in fatness rather than inherent breed factors.

The time required for recovery from mixing stress in young bulls and the prevention of dark cutting beef.

Two trials were conducted in which a total of twenty-eight Friesian bulls (12 months old) were slaughtered 0, 1, 2, 4, 7, 9 or 10 days after they had been mixed with unfamiliar animals overnight. The resulting behavioural interactions and associated physical activity led to large rises in plasma creatine phosphokinase (CPK) activity and free fatty acid (FFA) concentration and a decrease in plasma lactate. In the second trial the relative number of interactions engaged in by each animal was estimated. Bulls which exhibited the most interactions had the highest levels of plasma CPK and FFA after mixing. Liver and muscle glycogen were depleted by mixing. Animals killed on days 0 and 1 after mixing had low concentrations of liver glycogen compared with animals allowed longer to recover. Concentrations of glycogen in the M. longissimus dorsi (LD) had recovered by day 4 and in the M. psoas by day 2. Muscle glycogen concentrations were reflected in the ultimate pH (pHu) of the meat. All animals killed immediately after mixing produced carcasses with pHu>6. in the LD. By the second day of recovery muscle glycogen stores had been repleted sufficiently so that all animals had muscles with pHu<6. However, the LD from these animals was still very slightly darker than those killed after 7 or more days of recovery although this was probably not commercially significant. It was concluded that, if young bulls from separate rearing groups are mixed before slaughter, either on the farm or during lairage, then they require resting with food for at least 48 h before being killed to ensure that no carcasses are produced with high pHu in the musculature.

A note on the effects of perches and litter substrate on leg weakness in broiler chickens.

Two trials were conducted to investigate the effect of availability of perches on indices of leg weakness in broiler chickens. A third trial investigated the effect of litter substrate on similar indices of leg weakness in broiler chickens. Leg weakness traits examined were walking ability and tibial dyschondroplasia, tibial curvature, foot burn, and hock burn. Body weight was also measured in all trials. The presence of perches in the rearing pens had no effect on any of the indices of leg weakness examined in either trial. There were no consistent effects of perches on BW. Litter substrate significantly affected some indices of leg weakness; birds reared on wheat straw had poorer walking ability and more foot burn than birds reared on wood shavings, and birds reared on hemp waste were intermediate between them. There was no effect of litter substrate on tibial dyschondroplasia or tibial curvature. Turning the straw litter regularly and adding fresh supplies when necessary did not significantly improve indices of leg weakness. It was concluded that wood shavings provide a better litter substrate than straw, but that perches have no beneficial effect on reducing leg weakness in broilers.

Effects of age and stocking density on leg weakness in broiler chickens.

The effects of stocking density (STD) on leg weakness in broiler chickens was assessed in two trials. The interaction between age and STD on leg weakness was further evaluated in one trial. In Trial 1, walking ability was assessed at 28, 42, and 49 d of age. Birds were stocked at 833, 625, or 435 cm2 per bird. In Trial 2, birds were stocked at 625 or 455 cm2 per bird and assessed for tibial dyschondroplasia (TD) by radiographic examination at 28 d and walking ability at 35 d. Foot pad burn, hock burn, and angulation of the hock joint were also assessed at slaughter on Day 42. Body weight was measured during both trials. At 4 wk of age, leg weakness was a relatively minor problem; few severely lame birds had a gait score (GS) of 4 or 5 at any density. However, 2 wk later, the birds had substantially poorer walking ability. Further deterioration had occurred by 7 wk of age. At all ages, males exhibited greater leg weakness than did females, and the proportion of severely lame birds increased with age of assessment. The effect of STD was consistent across both trials; higher STD were associated with poorer walking ability and reduced live weights. In Trial 2, higher STD resulted in more foot and hock burns. Females were more sensitive to STD than were males However, there was no effect of STD on the prevalence of TD or angulation of the hock joint. The effect of high STD on walking ability was apparent even at 4 wk of age. Adjusting the observations for differences in BW did not alter the findings. It was concluded that the lower STD substantially reduced the prevalence of leg weakness.

The effect of photoperiod:scotoperiod on leg weakness in broiler chickens.

Four trials were conducted to investigate whether manipulations of photoperiod:scotoperiod affected the prevalence of leg weakness in broiler chickens. Modified photoperiods were applied from 3 until 21 d of age, followed by gradual or immediate return to 23 h light. The photoperiods tested were 8, 16, 21, and 23 h light. Leg weakness was assessed by measuring walking ability by gait scoring (GS) and tibial dyschondroplasia by x-ray (TD). Foot burn, hock burn, angulation of the hock joint, and BW were also measured. In total, 4,640 birds were assessed. The responses of the birds across the four trials were consistent. Increased photoperiod was associated with increased BW and prevalence of TD. There was no clear relationship between photoperiod and GS but foot pad burns were reduced by longer photoperiod. When the data were adjusted for differences in BW, increased photoperiod was associated with increased prevalence of TD, better walking ability (GS), and fewer hock and foot pad burns. Strong correlations were found between GS and live weight, and weak correlations with hock burn and TD. Tibial dyschondroplasia was weakly correlated with BW. The linear regressions of GS on live weight, within sex, across trials, were not different, but there was a difference between sexes, with males having a higher intercept but lower slope than females. It was concluded that shorter photoperiod affected walking ability and TD, but that these effects were largely a result of BW.

Meal feeding is more effective than early feed restriction at reducing the prevalence of leg weakness in broiler chickens.

Two trials were conducted to investigate whether manipulation of feeding pattern or early feed intake affected the prevalence of leg weakness in broiler chickens. In Trial 1, the birds were offered two, three, or four meals per day or consumed feed ad libitum. In Trial 2, a multifactorial design was used with age at start, duration of restriction, and severity of restriction as factors. The start of restrictions were at 5, 7, or 9 d, duration of restriction was 5 or 7 d, and feed was restricted to achieve 25, 50, and 75% of predicted growth during the restriction period. Ad libitum birds served as controls. Leg weakness was assessed by gait scoring (GS) and tibial dyschondroplasia (TD) by radiography. Foot burn, hock burn, angulation of the hock joint, feed consumption, and body weight gain were also assessed. The response of the birds to meal feeding was clear. Fewer meals per day was associated with less TD, less hock burn, better walking ability, lower body weight, and better feed conversion. The response of the birds to feed restriction was also clear. Earlier restriction, longer duration, and more severe level of restriction were all associated with lower prevalence of TD, better walking ability, lower body weight, and better relative growth rates and feed efficiency. However, adjusting the observations for differences in body weight removed many of the significant differences; only birds that started feed restriction earlier had less TD. From these trials, it was concluded that meal feeding can beneficially affect the prevalence of leg weakness, and that the major part of this effect is independent of changes in body weight. It was also concluded that early feed restriction reduced many aspects of leg weakness, but that these effects were mainly a result of reduced body weight. Meal feeding and early feed restriction improved feed efficiency.

Different commercial broiler crosses have different susceptibilities to leg weakness.

A trial was conducted to investigate the susceptibility of different genotypes of broilers to leg weakness. Four crosses of commercial broiler lines were assessed. Birds were reared on commercial diets at commercial stocking densities. Indices of leg weakness examined included: walking ability, tibial dyschondroplasia (TD), foot pad burn, hock burn, and angulation of the hock joint. Body weight and feed efficiency were also measured. There were small differences in BW and feed efficiency among the commercial crosses; however, there were large differences in some of the indices of leg weakness among the crosses. Three crosses had similar prevalence of TD; one cross had much less TD than the others. There were large differences in walking ability among crosses. There were also differences among crosses in the prevalence of foot pad and hock burn and angulation of the hock joint. Adjusting the observations for differences in BW did not substantially alter the findings. There were differences among genotypes regarding the correlation coefficients between walking ability and BW, walking ability and hock burn, and TD and BW. It was concluded that there were large differences in some important traits associated with leg weakness among the commercial line crosses.

Molecular typing of strains of staphylococcus aureus isolated from bone and joint lesions in lame broilers by random amplification of polymorphic DNA.

A study was conducted to investigate the relationship between the presence of localized bacterial infection and lameness in broiler fowl (Gallus gallus domesticus). Isolation of bacteria from the proximal femur, proximal tibia, and tibiotarsus from broilers with lameness revealed a probable association between lameness and the presence of Staphlylococcus aureus. Other potential pathogens, including Escherichia coli and DNase-negative staphylococci, were also isolated from sound and lame birds, and their association with pathologies causing lameness was less well defined. After trials with a set of twenty 10-base oligonucleotide primers, a pair of primers giving optimal performance was selected. The S. aureus isolates were typed by random amplification of polymorphic DNA (RAPD) by using the pair of 10-mer primers, and groupings were defined by banding patterns after agarose gel electrophoresis. The putative RAPD groupings may provide a basis for epidemiological studies of S. aureus in broiler production systems.

Review of welfare concerns relating to commercial and special permit (scientific) whaling.

This paper reviews recent data relating to the efficiency and humaneness of the methods used to kill minke whales in commercial and special permit whaling operations. In the 1980s a grenade-headed harpoon was developed for minke whaling. Most recent results indicate that in the Norwegian industry approximately 60 per cent of whales were considered to be killed immediately by this harpoon, with 40 per cent being wounded. However, in Japanese whaling operations, generally only 30 per cent of whales were killed immediately, with 70 per cent being wounded. In both operations, more than six minutes elapsed before half the wounded whales were pronounced dead, with some whales surviving for more than an hour after being harpooned. Many of the long killing times were associated with a failure of a part of the whaling equipment

Evaluation of baseline indices of sensibility in captive cetaceans.

Twelve possible tests of sensibility and six possible tests of vitality were evaluated for their ease of application and the reliability of the animals' responses in 25 animals of six species of captive cetaceans. The protocols for the application of the tests and the responses observed are described.

Response of newly hatched chicks to inanition.

Newly hatched chicks were kept for up to 48 hours without food and water and compared with a control group of chicks given access to food and water within six hours of hatching. The deprived chicks progressively lost body water and developed increases in plasma total protein concentration consistent with a decrease in plasma volume. They demonstrated a stronger motivation to drink and drank more when offered water, suggesting that they had become dehydrated. There was evidence, however, that normally access to food was necessary to initiate drinking. The deprived chicks continued to rely on fat metabolism to supply their energy needs whereas the fed birds showed rapid reductions in circulating levels of beta-hydroxybutyrate and increases in plasma glucose and liver glycogen concentrations, indicating a change to carbohydrate-orientated energy metabolism. The deprived chicks lost weight at an average of 0.14 g/hour and weighed 16.5 g less than the fed chicks after 48 hours.

Relationships in broiler chickens between lameness, liveweight, growth rate and age.

Thirteen genotypes of poultry were selected to represent a wide range of growth profiles and were fed either a non-limiting or Label Rouge diet. The birds' degree of lameness and liveweight were measured after 54 and 81 days. The birds reared on the Label Rouge diets were less lame than birds of the same genotype reared on the non-limiting diet. More traditional and slower growing genotypes tended to be less lame than the modern genotypes reared on the same feeding regimen. All the birds, irrespective of their genotype or diet, were less lame after 54 days than after 81 days. However, when liveweight was included in the analysis as a covariable, many of the differences disappeared. Only age at assessment significantly affected the walking ability of the birds, with the birds being approximately 0.6 units of gait score worse at 54 days of age than at 81 days. The regression coefficient between gait score and liveweight was 1.262 at 54 days and 1.128 at 84 days. The results indicated that liveweight was an important determinant of lameness in the diverse range of genotypes examined, that growth rate was also an important determinant of lameness and that younger birds may be more sensitive to differences in liveweight than older birds.

Effect of slaughter by removal from water on visual evoked activity in the brain and reflex movement of rainbow trout (Oncorhynchus mykiss).

The effects of removal from water and death by anoxia on brain function and reflex movement were examined in conscious trout. Visual evoked responses (VERS) were measured in fish with a body temperature of 20 degrees C, 14 degrees C and 2 degrees C. On average the fish took 2.6 minutes at 20 degrees C, 3.0 minutes at 14 degrees C and 9.6 minutes at 2 degrees C to lose VERS, and 11.5, 27.7 and 197.6 minutes, respectively, to lose all movement. VERS were absent from fish anaesthetised with MS222. From a humanitarian standpoint these results indicate that fish killed by anoxia could be exposed to periods of distress or suffering, and that cooling them in ice prolongs this period.

Protocol for assessing brain function in fish and the effectiveness of methods used to stun and kill them.

A method for the evaluation of brain function in fish has been developed which is based on assessments of self-initiated behaviours, responses to stimulation, and reflexes. These assessments were validated in several freshwater and marine species and applied to evaluate the brain function of fish while they were anaesthetised and while they were being killed by a variety of methods. The results of these investigations were compared with published neurophysiological observations and it is concluded that some of the tests can be used to identify, with reasonable confidence, the state of awareness, and thus the capacity to experience suffering of several species of fish.

Prevalence of leg weakness in broiler chickens and its relationship with genotype.

A method for measuring the prevalence of leg weakness by assessing the walking ability of broilers was developed. Walking ability was divided into six categories, from completely normal to immobile. The method was found to give consistent results when performed by the same people. In a survey of commercial, intensively reared broilers, 90 per cent had a detectable gait abnormality and 26 per cent suffered an abnormality of sufficient severity for their welfare to be considered compromised. The prevalence of leg weakness in free range broilers, and three commercial breeds of broilers was determined. The results indicated that genetic factors were an important cause of leg weakness in broilers and also identified a possible relationship between liveweight and leg weakness.