2. Plasma VLDL concentrations were consistently higher at all ages in fat line hens but were not affected by dietary treatment.
3. Mature body weight did not differ between the lines in birds fed ad libitum but with food restriction throughout life, fat line birds were lighter at 34 weeks.
4. There was little difference between the lines in abdominal fatness of birds fed ad libitum up to 60 weeks. Fat line birds were always fatter than lean line counterparts under food restriction.
5. Egg production was higher in lean line birds fed ad libitum but food restriction improved egg production in both lines. Peak egg productions were similar in both lines but there was evidence that the optimal food allowances for egg production was higher in the lean compared with the fat line.
6. Ovarian yellow follicle numbers were highest at 34 weeks in ad libitum fed lean line birds and declined linearly with decreasing body weight caused by food restriction but there was no such relationship in fat line birds.
7. White follicle numbers were higher and follicular atresia was lower in the lean line.
8. It is concluded that poor reproduction in fat line birds was associated with inhibition of follicular development and atresia rather than by high plasma VLDL concentrations promoting excessive yolk formation. 相似文献
2. Iiveability in laying hens was improved by the use of intermittent lighting: the degree of improvement was proportional to the reduction in daily illumination achieved by the intermittent programme.
3. The reduction in mortality with intermittent lighting in laying hens was not the result of intermittent lighting per se. Intermittent regimens which did not reduce daily illumination did not reduce mortality.
4. Mortality in both conventionally‐lit laying hens and 49‐d old‐broiler chickens increased with photoperiod. 相似文献
2. Hens subjected to 2L:4D:8L:10D lighting had lower body weights at end of lay and during most of the laying year, than the 17L:7D control birds.
3. Intermittently illuminated hens had similar absolute water, crude protein and ash contents to, but more water on a proportional basis than, controls.
4. Hens subjected to the 2L:4D:8L:10D lighting regimen had significantly less fat, in both absolute and proportional terms, than the controls.
5. There were no significant differences between the energy concentrations of the fat or fat‐free components of the two lighting groups.
6. There was no significant difference in the regression of fat content on body weight at end of lay for the intermittently and conventionally‐illuminated birds.
7. A prediction of the difference in daily energy requirement, based on egg output, body weight and mean daily body weight gain, very closely matched the actual difference in energy intake. This suggested that the more efficient food utilisation of intermittently‐illuminated hens could be explained by the lower body weight gain of these birds. 相似文献
2. Hens of the population with the high incidence of whitening appeared to be more fearful than hens of the population with the low incidence of whitening.
3. Brown colouration of the egg shell and the incidence and degree of shell whitening declined as the hens aged.
4. Brown colouration and egg shell whitening were most pronounced on the blunt ends of the eggs.
5. A large part of the variation in egg shell whitening was attributable to the individual (hen) component of variance.
6. Differences in egg shell whitening, between the two populations, were detectable throughout the 26 weeks of the experiment.
7. Oviposition intervals were similar for normal and coated eggs when birds were not exposed to disturbance.
8. Disturbance of hens increased oviposition intervals and the incidence and degree of shell whitening, to a similar extent, in both populations.
9. It is concluded that stress‐related egg retention is not the sole factor responsible for abnormal egg shell whitening. Shell whitening may occur as a consequence of the premature termination of shell pigmentation as well as a consequence of the retardation of oviposition which occurs when hens are disturbed. 相似文献
2. In experiment 1 with hens caged individually, treatment groups comprised relocated hens given 5 new neighbours and hens not relocated but given 0, 2 or 4 new neighbours.
3. In experiment 2 with hens housed two per cage, treatment groups comprised relocation with or without that hen which shared the cage before the move.
4. In both experiments relocated hens laid fewer eggs in the week following social reorganisation.
5. Relocated hens in experiment 1 ate less food in the week following the shift at 42 weeks of age than did hens not moved. In experiment 2 in which all hens were moved, food consumption was not affected. 相似文献
2. Birds in conventional deep cages were more active than those in shallow cages in each of four different periods of day. Activity reached a peak between 11.00 and 13.00 h irrespective of cage shape.
3. Mean feeding activity was greater in the shallow (45.6%) than in the conventional deep cages (39.9%).
4. Mean feeding activity was greater in birds fed ad libitum (43.3%) than in those fed on a restricted diet (40.4%).
5. Although restricted birds in shallow cages showed more feeding activity than those in conventional deep cages they consumed less food (56% against 67%) in the 7 h between supply of their daily ration and the onset of the dark period.
6. Feather damage was greater in the conventional deep cages than in the shallow cages.
7. The more efficient utilisation of food by hens in shallow cages is probably due largely to three factors: reduced levels of motor activity and general disturbance, a more leisurely eating pattern and better feather cover. 相似文献
2. Battery caged hens had the poorest bones, as assessed by measurements of cancellous bone volume, radiographic density, cortical thickness and three‐point breaking strength.
3. Humeri from birds in the Litter and Wire system were less dense radiographically and weaker than those from Perchery or Naturel birds but leg bone characteristics were similar with these three systems.
4. There were no differences in bone characteristics between birds in Perchery and Naturel systems.
5. There were strong correlations between radiographic densities and strengths of contralateral humeri and tibiae over all husbandry systems. Humerus structural and strength characteristics may be the best criteria of osteoporosis in hens.
6. It is concluded that the extent of movement allowed by different husbandry systems affects structural bone loss and bone strength in laying hens.
7. It is further concluded that the breaking strength of a hen's bone is closely related to morphometric measures and radiographic density of its structural components. 相似文献
2. The rate of increase in deep‐body (rectal) temperature during exposure to 32°C was used as the index of thermoregulatory ability. Comb and foot surface temperatures were measured as indicators of peripheral vasomotor tone.
3. Because body temperature control depends on the balance between heat production and heat loss, heat production was measured to determine whether fat line hens had a higher heat production, which they would then have to dissipate.
4. During the first hour of heat exposure, rectal temperature in the ad libitum‐fed birds increased twice as rapidly as in the corresponding lean line sample and 6 times more rapidly than in the control‐fed fat‐line group.
5. Surface temperatures of comb and foot increased from 27°C to 37°C within the first hour at 32°C, with no effect of either genotype or feeding regimen on rate of increase.
6. Heat production was unrelated to genotype but was reduced by 23% by controlled feeding, largely because of the reduction in body weight.
7. The results demonstrated that ad libitum‐fed fat‐line birds are susceptible to heat stress and that this is related not to increased heat production, but to a decreased ability to lose heat. Elevation of blood viscosity by plasma triglycerides is suggested as a causal factor. 相似文献
2. There was little difference between the broiler breeder strains except in body weight at 16 and 18 weeks of age.
3. Food intake relative to body weight was higher in the broiler breeders compared with the layer strain.
3. The degree of restriction was defined as the food intake of re‐stricted birds as a proportion of the estimated intake of birds of the same body weight fed ad libitum. The value declined from 0.60 to 0.45 during the rearing period.
5. In the ad libitum treatments broiler breeders drank more than layers, whereas when restricted, layers drank more than broiler breeders.
6. Water intake was 2.50 times higher in restricted compared with ad libitum‐fed layers and 1.25 times higher in restricted than ad libitum‐fed broiler breeders, with free access to water. 相似文献
2. A 25000 kDa purified recombinant derived turkey prolactin (rtPRL), the biological activity of which was tested using a crop sac assay, was used as immunogen for the production of rabbit antiserum. In this biological test, the rtPRL was as active as the ovinePRL.
3. The radioligand (rtPRL) was labelled with 125I and the assay allowed the detection of standard doses of rtPRL ranging from 400 pg/tube to 50 ng/tube.
4. No cross reaction with chicken luteinising hormone and recombinant chicken growth hormone was detected.
5. The within and between assay coefficients of variability were 5.0 ± 2.7% and 16.3%, respectively. The overall mean recovery ratio was 1.01.
6. The dose‐response curves obtained with serial dilution of plasma and pituitary from turkey hens at different physiological stages and from male turkeys were parallel to those obtained with standard rtPRL.
7. The measured concentration of prolactin was 5 times higher in plasma from incubating than laying turkey hens, and the pituitaries from incubating hens contained 2 and 4 times more prolactin than those of laying and out of lay hens or males, respectively.
8. To further assess the validity of the assay, we measured changes in plasma concentration of prolactin in turkeys following stimulation with chicken vasointestinal peptide (cVIP). A single injection of 1 or 10 μg/kg body weight of cVIP to laying hens produced a large and rapid increase in plasma prolactin.
9. This new radioimmunoassay appears to be highly specific and sensitive for the measurement of turkey prolactin. 相似文献
2. Food‐restricted birds spent a large proportion of time scratching and pecking the litter compared with birds fed ad libitum.
3. The heterophil/lymphocyte ratio and the proportion of basophils were raised at 8, 12 and 16 weeks, and the plasma concentrations of corticos‐terone were higher at 8 and 12 weeks of age in restricted birds compared with those fed ad libitum.
4. Creatine kinase activity was higher in broiler breeders fed ad libitum compared with layers and restricted broiler breeders. The activity of aspartate transaminase was higher in restricted layers compared with birds fed ad libitum and was similar in broiler breeders.
5. Plasma viscosity was lower in food‐restricted compared with ad libitum‐fed birds.
6. Limiting access to water had little or no effect on the welfare indicators although food‐restricted birds with free access to water spent more time drinking than birds fed ad libitum.
7. There were no important differences between the two broiler strains. Layers spent less time resting than broiler breeders and had higher plasma corticosterone concentrations at 3 and 16 weeks of age.
8. It was concluded that there was evidence for physiological stress associated with restricted feeding at least between 8 and 16 weeks of age. It was suggested that the altered behaviour of broiler breeders kept on litter may indicate that they can cope with food restrictions and that this may be acceptable in relation to the long‐term benefits of limiting body weight during rearing. The same may not be true for layers. 相似文献
2. An Individual Poultry Weighing System (IPWS) was developed to record time, duration, location and body weight of visits of individual hens to 4 weighing scales.
3. The number of hens that visited the weighing scales per 3 h period varied from less than 10 during the dark‐period to more than 60 during the light‐period.
4. The average number of visits per individual hen was 1–4 and the average number of successful weighings per hen was 0–6 during the light‐period.
5. Body weight showed a diurnal rhythm: the difference between the maximum body weight at night and the minimum body weight in the morning was 63 g.
6. The location of the scales influenced number of visits, number of weighings, mean body weight, flock‐uniformity and duration of visits.
7. Body weight per 3 h period did not differ between hens which were individually recognised and those which were not.
8. Flock‐uniformity was 2–6% higher during the light‐period if it was based on weighings of identified hen visits.
9. The average duration of the visits to the scales in the middle of the feeding tier during the light‐period was 63 s.
10. Of all the hens that visited the scales during a 24 h period, 54% visited them only once.
11. Automatic weighing systems without individual hen recognition can deliver reliable management information on mean body weight and flock‐uniformity in aviary systems if the weighing scales are located on the feeding tier in the middle of the house and if they are used during the light‐period. 相似文献
2. Diet B, as mash, showed a lower apparent physical density than the others. The hardness and durability of the pelleted diets were similar.
3. Hens fed the mash diet B could not completely adjust their food intake to compensate for the dilution and showed reduced egg output and body weight gain compared to the other groups.
4. Video observation of each hen for 14 consecutive hours showed that mash‐fed hens ate for longer periods than pellet‐fed hens during the first 11 h (proportion of time spent eating: 41.3% mash B, 32.5% mash A and 20% to 25% for all the pelleted diets). These differences were less pronounced during the last 3 h of the photoperiod.
5. Trough‐oriented stereotypies were noted in 14 out of 22 mash‐fed hens and in 12 out of 47 pellet‐fed hens. Dilution of the diet did not appear to exacerbate stereotyped behaviours under the conditions of the study.
6. This experiment demonstrates that the feeding behaviour of laying hens is affected by the physical characteristics of the diet and that this may lower their productivity.
7. Low‐energy pelleted diets might be used to feed hens efficiently in tropical countries where cereal by‐products are abundant. 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. Lighting affected growth pattern but had no effect on body weight at 118 d or overall food to gain ratio.
3. Both INC and DID lighting reduced overall mortality in comparison to CON light primarily because of a reduction in the incidence of skeletal disease and spontaneous cardiomyopathy. INC and DID lighting increased the incidence of cannibalism.
4. Turkeys given INC or DID lighting had a superior ability to walk in comparison to those birds given CON light.
5. INC and DID males stood, ate and drank more frequently, and sat less often than CON turkeys during behavioural observation.
6. There were no lighting effects on carcase composition except that INC and DID birds had heavier keel bones. The ultimate force per cm2 (stress) required to break femora was greater for turkeys given INC and DID lighting (P = 0.065).
7. Plasma testosterone concentrations at 117 d were 272.5, 115.2 and 29.5 pg/ml for turkeys given CON, INC and DID lighting, respectively (P= 0.072). Testosterone concentration was not related to growth rate. 相似文献
2. Treatments did not affect egg numbers, food consumption, conversion efficiency of food to egg, bodyweight gain or mortality.
3. Increasing dietary calcium (Ca) significantly increased plasma Ca and inorganic phosphorus (P), breaking strength at the radius and egg specific gravity and significantly decreased plasma alkaline phosphatase and egg weight.
4. Increasing dietary phosphorus increased plasma P and decreased egg specific gravity significantly.
5. Plasma Ca, P and alkaline phosphatase and radius breaking strength were suitable indices of the Ca status of the hens. 相似文献
2. Almost 20 different genotypes (brands) were present on the farms. In France, all birds were brown feathered hens laying brown eggs. In Switzerland and The Netherlands, there were brown, white (white feathered hens laying white eggs) and silver (white feathered hens laying brown eggs) hens. In Switzerland, mixed flocks were also present.
3. The overall effect of system (organic vs. conventional free range) on egg production and mortality was significant, with higher mortality and lower egg production among organic hens. In pair wise comparisons within country, the difference was highly significant in The Netherlands, and showed a non-significant tendency in the same direction in Switzerland and France.
4. White hens tended to perform better than brown hens. Silver hens appeared to have a higher mortality and lower production per hen housed at 60 weeks of age.
5. There were no significant relationships between production, mortality, feather condition and use of outside run or with flock size.
6. There was more variation in mortality and egg production among farms with a small flock size than among farms with a large flock size. 相似文献
2. The response in shell thickness to ahemeral lighting was more rapid (2.2 d) than for egg weight (4.2 d).
3. Differences between genotypes were evident in both the speed and magnitude of response.
4. Overall, egg weight and shell thickness on the 28‐h cycle were 7% and 8% greater than on 24 h.
5. The allometric increase indicates that the increase in shell weight was on average 14% more than the increase in egg weight. 相似文献
2. Room treatments were a standard lighting pattern with intensities of 0.5, 2 and 15 lux and an intermittent pattern (3 h light: 3 h dark) at 15 lux. Within room treatments were ad libitum or rationed feeding during rearing and 4 breeds: ISA Brown, Hisex Brown, Shaver Brown and Hisex White.
3. Rationing during rearing, by holding intake at its 6‐week level from 6 to 14 weeks of age, was associated with significantly higher egg production and lower egg weight, but no effect on food intake, or egg output.
4. Intermittent lighting, using a repeated 3L:3D regimen was associated with higher egg weight, but a lower rate of lay, food intake, and total egg output.
5. The absence of a consistent response to light intensity, over the range 0.75 to 12.4 lux was in contrast with earlier work, and it is possible that modern prolific hybrids are more tolerant of low intensity than were earlier stocks.
6. Despite this result it is suggested that current recommendations of 10 to 20 lux in laying houses need not be changed, because such intensities are advisable on the grounds of welfare, staff working conditions and aesthetics. 相似文献
2. Photoperiod treatments consisted of computer simulations of day lengths which occur naturally in the spring and autumn of the year. Both photoperiod treatments were given to hens in the autumn and spring.
3. Data were collected for growth evaluations at 2‐ to 4‐week intervals to 16 weeks of age. No significant season × photoperiod interactions occurred.
4. The spring trial resulted in greater body weights and better food conversions (food/gain) than the autumn trial.
5. Simulated autumn daylengths resulted in greater body weights and improved food efficiency at 16 weeks of age compared with simulated spring daylengths.
6. The pattern of growth (period changes) was influenced by season, but not photoperiod.
7. Season and photoperiod both have important and independent influences on the growth of the turkey hen. 相似文献