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. Based on the variance of the full‐sib family means, the heritability estimates for pure‐bred, cross‐bred and for the combined data were 0.lb186 ± 0.lb105, 0.lb065 + 0.lb021 and 0.lb088 + 0.lb005, respectively: the results showed absence of non‐additive genetic variance for hatchability.
3. Fertility was influenced more by sire strain than by the dam while hatchability was primarily influenced by the dam strain.
4. The sire x dam interaction effect was significant for fertility but not for hatchability.
5. Fertility was influenced by crossing two divergent strains. 相似文献
2. No significant differences were found between genetic groups in hatchability.
3. Groups containing the fast‐hatching line genotypes were significantly smaller in egg weight than those not containing this line.
4. Significant differences in hatching time existed between male lines and between female lines within pure and cross‐line parent types while no differences were observed between the female parent types and no interactions of male by female lines occurred.
5. It was concluded that inbreeding in the pure lines (10%) did not affect any of the variables measured.
6. The results on hatching time support the conclusion that little genetic variance other than additive variance is involved for this trait. 相似文献
The aim of this experiment was to determine the profit returned at 12 weeks by broiler chickens hatched from eggs ranging in weight from 44 g. to 58 g. at one gram intervals and to determine how competitive and separate rearing might modify the relationship.
A total of 6000 eggs were collected during 10 days from a 28‐week‐old, broiler breeding flock and graded into the above mentioned egg weight classes. From these, a total of 3480 day‐old broilers were housed. Each egg weight class was equally represented and balanced for sex.
Hatchability and fertility showed no consistent trend with egg weight for eggs above 46 g., but below the 47 g. level there was a trend of declining fertility and hatchability.
A strong positive relationship was found between the weight of the chick at 1 day of age and egg weight for both males and females with no significant difference overall in body weight between the two sexes.
Body weight to 12 weeks was found to be strongly related to egg weight, in a linear fashion, though this influence declined with age.
There was a greater influence of egg weight on body weight at all ages in the separate rearing treatment compared with competitive rearing but this was not significant after 10 weeks.
Egg weight had an important bearing on body weight and profit at 12 weeks, but no effect on food conversion or mortality.
The increased profit over food costs per 100 day‐old chicks was found to be 52.75 cents for the separately reared birds respectively for each 3 g. increase in egg weight. 相似文献
2. Also, in an aseptic laboratory trial, eggs from Large White turkey hens were injected with 0.2 ml of saline solution and 0.2 ml of saline solution containing 600 μg of pyridoxine hydrocholoride.
3. In field trials, hatchability of pyridoxine‐injected eggs was 4.6% higher (P<0.05) than the control (non‐injected) eggs.
4. In the aseptic laboratory trial, hatchability of pyridoxine‐injected eggs was 4.2% higher (P<0.05) than saline‐injected and control (non‐injected) eggs. 相似文献
2. Yolk and albumen riboflavin concentrations were depressed by the deficient diets and cases of curled toes were seen in the chicks.
3. The few instances of defective down did not resemble cases seen in field outbreaks of a condition involving depressed hatchability and a defective down syndrome.
4. It is concluded from observations in this experiment and in the field outbreaks that there is a condition in breeding chickens causing depressed hatchability and defective down that is not attributable to riboflavin deficiency. 相似文献
2. Mass specific eggshell water vapour conductance, Gsp, increased by approximately 50% over about 13 weeks during the winter breeding cycle. A similar increase occurred over 8 weeks during summer.
3. Constant setting of humidity in goose incubators and changes in mean Gsp may cause sub‐optimal egg water loss which increases late mortality.
4. Mean Gsp was measured for every batch from each flock. Humidity was changed accordingly in order to reach optimal water loss. A significant improvement of 6% in hatchability and of 8% in Class‐A goslings was noted during 14 successive weeks compared with the previous 11 weeks.
5. Dynamic humidity control for optimising water loss according to mean batch Gsp thus increases hatchability. 相似文献
2. All treatments that can be characterised as being less optimal for embryo survival than the control treatment affected the hatchability of fertile eggs more in the case of eggs produced by older birds.
3. A higher temperature in the nest box, longer storage periods, higher storage temperature, especially at longer storage periods, and higher pre‐setting temperature significantly reduced the hatchability of fertile eggs from the older birds.
4. For the younger birds, a significant reduction of hatchability was found only for the longest storage period. 相似文献
2. These eggs were stored at room temperature (27°C‐31°C) or in an air‐conditioned room (20°C‐23°C), for two, three, six or seven days and incubated in four replicate hatches.
3. Eggs kept SEU improved hatchability even for short‐term storage when temperatures were high.
4. Simple air‐conditioning can reduce the temperature sufficiently for the viability of the embryo to be preserved for up to a week. 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. 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
2. Using one of these methods a survey was conducted on eggs which had failed to hatch from commercial hatcheries.
3. An assessment of the level of contamination in the eggs examined indicated an average level of contamination of 12.7%.
4. The contaminating flora was composed mainly of Micrococcus sp. and Enterobacteriaceae, with Streptococcus sp., Staphylococcus sp., Bacillus sp. and Pseudomonas sp. present at lower levels.
5. Various interrelationships between contamination and hatchability are discussed. 相似文献
2. The commercial broilers were divided into 2 groups of 100 birds each; CoQ9‐treated group and non‐treated group.
3. The chickens were grown in a positive‐pressured house with double high efficiency particulate air filtered intakes and exhaust, and thus were strictly isolated from infectious agents.
4. The chickens (15 to 21 d old) were exposed to cold stress in order to induce ascites.
5. The number of birds with ascites in the C0Q3‐treated group was significantly lower than in the non‐treated group.
6. Survival and production rates were better in the CoQ^‐treated group than in the non‐treated group. 相似文献
2. 18% to 21% of eggs in each batch were contaminated with bacteria and fungi, with the latter being found more often in eggs which contained more advanced embryos.
3. Although infertility and prolonged storage reduced hatchability, the high inci dence of microbial contamination in ostrich eggs is deemed to be a significant problem.
4. Improving nest hygiene is considered to be the simplest way to reduce microbial spoilage. 相似文献
2. Deformation was not completely reversible due to crumbling at the points of contact with the force.
3. There are three components of non‐destructive deformation: (a) local deformation at the points of contact, (b) local surface crumbling and (c) deformation of the over‐all shell structure.
4. The latter two are uncontrolled, contributing to errors in the prediction of fracture force and depending on the non‐destructive force applied.
5. These effects should be considered in test selection and interpretation.
6. The optimum non‐destructive force was found to be 1 kg. 相似文献
2.?A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation.
3.?During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity.
4.?It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight.
5.?It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity.
6.?At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity.
7.?Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter.
8.?Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case.
9.?Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition.
10.?This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development. 相似文献
2. Food intake, weight gain and egg production were not affected by mycotoxin administration. No significant differences were found between groups.
3. The overall results from the hatching tests did not reveal any significant differences in fertility, hatchability or perinatal mortality, which could be explained by the mycotoxin content in the diets.
4. Body weight at hatching and viability of the chicks were not affected by the mycotoxin concentrations in the diets.
5. The incidence of chick developmental anomalies was increased in the mycotoxin‐administered groups compared to controls. Minor malformations were the dominating anomalies and included unwithdrawn yolk sac and delayed ossification. The most frequent major malformations were cloacal atresia and cardiac anomalies. 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. Changes in plasma cholesterol were equivocal, though there was perhaps a trend towards hypercholesteraemia.
3. Birds became hypoglycaemic within an hour but were hyper‐glycaemic between 2 and 4 h. At 24 h they were normoglycaemic.
4. Plasma corticosterone was increased markedly at 1 h but was decreased compared with the control at 2 h (P<0.01). Thereafter the concentration was in the normal range.
5. There was an enhanced hyperlipacidaemia in the treated birds after 1 h.
6. Adrenal cholesterol stores were decreased by 10% at 4 h but were unaffected at all other times.
7. Colonic temperature decreased by 1–6 °C after 2 h but was normal by4h.
8. It is concluded that propranolol has mild stressor activity which is lost within 24 h. 相似文献