2. Broiler chickens were electrically stunned with 81 mA per bird and then allocated to three treatments. About 67% experienced a VF at stunning and half of these birds were bled out before processing while the other half were processed without being bled out. The birds which did not experience a VF at stunning were bled out before being processed. The carcases were subjectively graded for haemorrhagic conditions.
3. Inducing a VF at stunning caused increases in the incidence of red wingtips and haemorrhaging at the humerus‐radius joint in the birds which were bled out. There were no other obvious effects of inducing a VF on carcase downgrading.
4. Failure to bleed the chickens which had a VF at stunning resulted in high incidences of red wingtips, red necks, haemorrhaging at the humerus‐radius joint and red sternal feather tracts. It was concluded that bleeding efficiency was important in influencing the expression of these characteristics when a VF occurred at stunning. 相似文献
2. The ducks were less susceptible to a ventricular fibrillation than chickens or turkeys, but a stunning current of 250 mA induced a ventricular fibrillation in 99% of the birds.
3. The incidence of reddening of the rear margin of the wing was lowest in the 85 mA current treatment. The incidence of the following conditions was not affected by stunning current: red pygostyles, red wingtips, wing haemorrhaging, engorgement of the wing veins, breast and leg muscle haemorrhaging, and broken furcula and coracoids. 相似文献
2. The least floor area (0.035 m2/bird) depressed production in two‐bird cages. Floor area had little effect on the performance of larger colonies.
3. Birds in colonies of three, four or six laid and survived equally well when feeding space/bird and floor area/bird were constant.
4. Production per hen d and food intake were higher, but return on estimated capital outlay was lower, with 102 mm than with 76 mm feeding space/bird when colony size and floor area/bird were constant.
5. Production and food intake of birds which were not treated to prevent cannibalism declined, and mortality increased, as cage depth increased from 385 to 915 mm concomitantly with increasing colony size from 2 to 7 birds and decreasing feeding space from 152 to 43 mm/bird.
6. Increasing cage depth did not increase the proportion of cracked eggs.
7. Mortality was higher among birds fitted with plastic spectacles than among debeaked birds. 相似文献
2. High frequency stunning (1500 Hz) caused a reduction in the incidence of broken bones compared with 50 Hz.
3. Battery birds had a higher incidence of recently broken bones in comparison with perchery and free range birds. However, there were more old breaks in the perchery and free range systems than in the battery system.
4. Breed of bird, age at sexual maturity and age at culling had no effect on the incidence of broken bones. 相似文献
2. Breast muscles (pectoralis major) were filleted at either 2, 3, 5 or 18 h post‐mortem, and pH and muscle temperature were measured at the time of filleting for the medium and large stags. The breast fillets removed soon after killing were stored at 3°C until transported to the laboratory.
3. All the breast fillets were cooked to an internal muscle temperature of 85°C and their texture was measured instrumentally. The fillets were weighed before and after cooking to determine the proportional cooking loss.
4. The results showed that, for electrical stunning, the rate of pH fall soon after killing differed between the bird types, and it resulted in a variable texture in the breast meat when filleting was performed soon after killing. The medium stags had a relatively slower rate of pH fall and filleting them soon after killing resulted in tougher breast meat.
5. By contrast, in all the three bird types, gas stunning resulted in a rapid pH fall soon after killing and produced tender breast meat at all the filleting times tested.
6. The cooking loss was higher in the large stags than in the medium stags or hens.
7. Stunning turkeys by anoxia or 30% carbon dioxide in argon would enable filleting to be performed soon after killing, and produce less variable‐and more tender breast meat. 相似文献
2. Two replicates of broilers (age 54 and 59 d respectively) were stunned in carbon dioxide, in argon or by electric current, and the carcases were plucked either by a mechanical plucker or by hand.
3. Carcase and meat quality were evaluated to determine the effect of these stunning treatments and plucking methods. The quality factors measured included pH at 20 min post‐mortem, ultimate pH, texture and colour of the pectoralis major muscle, and the incidence of carcase appearance defects, cooking loss, broken bones and bruises in the breast and leg muscles.
4. Stunning method had a significant effect on pH at 20 min, ultimate pH, texture and colour of breast meat. Plucking method had a significant effect on the cooking loss and texture.
5. Argon stunning resulted in fewer muscle haemorrhages, a more rapid early post‐mortem fall in pH and more tender breast meat than in the electrically stunned broilers; carbon dioxide stunned broilers had intermediate values for pH decline and meat tenderness but were not significantly different from argon stunning regarding muscle haemorrhages.
6. Appearance defects occurred to a similar extent in all the stunning methods and mechanical plucking resulted in 4 times as many defects compared with hand plucking; the incidence of broken bones was higher in mechanically plucked broilers than in hand plucked carcases.
7. Gaseous stunning of broilers produced relatively better quality carcases and meat than electrical stunning, and therefore may have commercial advantages. 相似文献
2. A transverse section of the thorax was examined and tissues including epithelium, fat, muscle, liver, keelbone and heart, were tested for the percentage of current flowing through each tissue.
3. It was found that the proportion reaching the brain varied from bird to bird whereas, with the exception of a slight variation in the proportion reaching the heart, that flowing through the other tissues located in the thorax was similar in all the birds tested.
4. The variability in current reaching the brain and to some extent the heart may determine whether a bird is stunned, inadequately stunned or killed after having entered a water‐bath stunner. 相似文献
2. More eggs were produced per hen housed from 30 to 70 weeks in the shallow cages; the difference approached significance.
3. The pattern of feeding activity over the day was significantly more U‐shaped in the shallow cages; this pattern accords more closely with physiological requirements.
4. Feather damage caused by pecking was slightly but significantly more severe in the deep cages at 70 weeks.
5. The proportion of cracked eggs (collected from 60 to 70 weeks) was significantly lower in the shallow cages.
6. The arrangement of the hens was such that within the shallow cages a higher proportion of birds was present in the front half.
7. It is suggested that some of the advantages conferred by the shallow cage may be related to the greater accessibility of the food trough. 相似文献
Digestibility trials are described, in which cockerels are compared before and after caecectomy; these birds after caecectomy are also compared with normal intact ones of the same age.
The trials showed a reduction in faecal dry matter after caecectomy, indicating that the caeca are active in absorption of water from the digesta. Faecal dry matter content seems to be more characteristic of the bird than of the food it eats.
There was a reduction in the overall digestibility of dry matter in the food after caecectomy, and also in that of crude fibre, though the latter effect is dependent on the food being eaten and on its crude fibre content.
Cellulose digestibility in a given bird was lowered, but the effect is not always evident between one bird and another, indicating that cellulose is digested bacterially in the caecum. No effect was found on pentosan and starch digestion. 相似文献
2. Vibration measurements were made using triaxial accelerometers mounted on the chassis and in the bird containers, with vehicles both loaded and unloaded.
3. In the vertical axis the fundamental vehicle frequency is between 1 and 2 Hz with a secondary peak at 10 Hz.
4. In the lateral axis with air suspension, the maximum level of vibration on the chassis occurred at 12 to 18 Hz; this was less evident with leaf suspension.
5. The magnitudes of vibration acceleration occurring in the bird containers would be fairly uncomfortable for the seated human. Frequency weightings and response to different axes and magnitudes of vibration must be established before the response of birds can be predicted. 相似文献
2. The meat samples were frozen at — 40° C and stored at — 20°C until they were thawed at 1°C and cooked at 85°C. They were subjected to sensory evaluation by 10 experienced assessors and instrumental texture measurements were made.
3. Only stunning method had significant effects on the sensory profile and instrumental texture. Breast meat from anoxia‐stunned turkeys was less firm on cutting, more tender and had a more powdery residue on eating than that from electrically‐stunned turkeys. The instrumental texture values confirmed that breast meat from anoxia‐stunned turkeys was more tender than that from the electrically‐stunned turkeys.
4. There was no significant correlation between the subjective tenderness rating and the instrumental texture value.
5. Principal components analysis showed that 59% of total variation was explained by the first two dimensions, the first being a contrast between turkeys that were tender and powdery and those that were firmer and fibrous. When values from individuals were plotted, this dimension was related to the differences between anoxia and electrical stunning, with anoxia‐stunned turkeys at the tender end of the first dimension. 相似文献
2. The water vapour conductance of fowl and Muscovy duck egg shells was not affected by the treatment.
3. Cuticle removal increased the conductance of turkey and goose shells, particularly those already relatively porous to water vapour.
4. Removal of cuticles from domestic duck egg shells increased water vapour conductance. In this case the effect was most marked for eggs with lower initial conductances.
5. The differing patterns of resistance to water vapour loss associated with egg shell cuticle are related to the ultrastructure of the cuticle itself, especially the number and size of cuticular fissures.
6. The results suggest that egg shell cuticle is a component in a series of resistances associated with the egg shell and that the use of Fick's Law is insufficient to explain water vapour diffusion across the shell.
7. Embryo survival may be improved by cuticle removal, though this may be limited to those species in which the cuticle restricts water vapour loss in initially low conductance egg shells. 相似文献
2. Higher rates of fertility and hatchability of Japanese quail eggs were observed from parents of 10 to 19 weeks of age, with peak fertility and hatchability at 14 and 12 weeks of age, respectively.
3. Sex ratios of 1:2 to 1:5 gave comparable fertility and hatchability results.
4. The hatching performance of quail eggs from cage and deep litter reared breeders was comparable.
5. Fertility and hatchability were directly proportional to the egg weight.
6. Quail egg shell colour, tints and blotches were found to influence hatching performance.
7. Storing quail eggs at 16 ± 2°C and 75 ± 5% relative humidity for more than 4 d reduced hatchability.
8. Hatchability of eggs stored at room temperature was improved if they were sealed in polyethylene bags.
9. Provision of light during the first 14 d of incubation resulted in a photo‐acceleration of about 3.2 h. 相似文献
2. Body weight gain, age at 50% egg production, mortality, hen‐day egg production and food conversion values showed significant improvement with proportionate increase in cage space per layer.
3. Egg weight gradually increased with age but shell thickness was influenced neither by age of the hen nor by stocking density.
4. Yolk index and colour were superior in the lowest stocking density (more cage space) group; other egg quality traits and egg weight were not influenced by stocking density.
5. The albumen index, internal quality unit, yolk index and yolk colour values increased with age. 相似文献
2. Approximately half of the flocks were fed on either a high (163 mg/kg) vitamin E or on a normal (44 mg/kg) vitamin E‐containing diet throughout production.
3. Approximately half of the flocks were the progeny of breeder flocks which had been fed on a high vitamin E‐containing diet throughout production.
4. The improvement in target income in the vitamin E‐supplemented broiler flocks was 8–44% (P < 0.01).
5. The residual improvement in target income in these flocks, after the cost of the additional vitamin E was taken into account, was 2.74% and failed to reach statistical significance.
6. The increased net income was achieved by a significantly improved food conversion ratio and average weight per bird (P < 0.05).
7. There was no overall effect of vitamin E supplementation of broiler breeders on subsequent broiler performance. 相似文献
2.?Factor activities decreased when lipids were depleted from the plasma of Single Comb White Leghorn (SCWL) and Fatty Liver Haemorrhagic Syndrome-susceptible (FLHS) laying hens.
3.?Addition of lipids removed from SCWL laying hens and FLHS-susceptible laying hens into lipid-depleted plasma of both bird strains caused an increase and decrease, respectively, in Factors V and X activities.
4.?Omega-3 fatty acids were negatively correlated to Factors V, VII and X activities. When bird strain was considered, it was significant for Factor X in SCWL laying hens. Omega-6 fatty acids were positively correlated with Factors VII and X for FLHS-susceptible laying hens.
5.?The results suggest that the type of fatty acid in plasma phospholipids influences the activities of Factors V, VII and X and by altering lipid composition in the plasma, activities of coagulation factors may be affected. 相似文献
2. An additional 40 broilers were stunned either by anoxia or by constant current electrical stunning (107 mA 50Hz) and their eviscerated carcases held overnight at 1°C prior to filleting at 24 h postmortem.
3. All the breast muscles (pectoralis major) were cooked at 24 h postmortem and their texture measured. The results indicated that the mean texture of breasts from the different stunning and filleting time treatments were similar, and there were no significant differences between them.
4. It is concluded that stunning with anoxia followed by a rapid chilling would enable the broiler carcases to be filleted at 1 h postmortem with no adverse effect on the texture of the meat. 相似文献
2. Hatchability was only 37.2% and the result of high rates of infertility and contamination (22.2% and 22.8% respectively); it varied between eggs from different farms.
3. Embryonic mortality was high at the start and end of incubation, a pattern similar to that of other domestic birds.
4. Mortality of late stage embryos was related to percentage water loss and mass specific water vapour conductance of the shell, with extremes of the ranges causing the highest mortality.
5. Microbial contamination of the eggs was a significant problem and varied in eggs from different farms indicating that more attention is needed in both breeder bird and nest management. 相似文献
2. A mathematical model has been formulated to demonstrate the effects of bird resistance and physical attitude of the bird on the current received by individual birds in a water bath stunner.
3. The model shows that readings from ammeters installed in series with commercial stunners, or the values shown on voltmeters, are not an accurate indicator or a guarantee that individual birds are effectively stunned.
4. The model demonstrates the need for a stunner to supply a constant current to each bird, rather than operate at a constant voltage where the current which the bird receives is dependant upon its own resistance. 相似文献
2. Hyperphagia, amounting to twice the intake of control birds early in the experiment, occurred on the repletion day.
3. Final body weight attained 80% of that of the controls.
4. Body fat concentration decreased at first but returned to that of controls after 3 weeks.
5. A consistent hyperlipaemia was observed after food deprivation or restoration.
6. There was a marked increase in the digestive enzymes found in the small intestine, but not in the pancreas during the repletion day.
7. These responses may be considered as mechanisms to reduce the physiological manifestations of starvation. 相似文献