2. Chick diets had no significant effects on rearing or subsequent laying performance.
3. Food‐regulated pullets were 7% lighter than pullets given the DPM diet ad libitum at 18 weeks but consumed 12.5% less food; growing treatments had no significant effect on subsequent egg production.
4. Hens housed in shallow cages laid 10.3 eggs/bird‐housed more than those in deep cages, produced 3.8% greater egg mass, consumed 2.7% less food and produced fewer damaged (cracked, broken and hair‐cracked) eggs (P< 0.001).
5. DPM‐containing layer diets had no adverse effects on egg production, or mortality; with 100 g DPM/kg efficiency of food conversion (EFC) was better than with 0 or 200 g/kg (P< 0.001).
6. Reduction of the energy intake of L110R and L220R hens with diets containing 110 and 220 g DPM/kg by 8.2 and 9.0% respectively, reduced the number of eggs laid/hen‐housed by 6 and 10.7 but improved the EFG (P< 0.001); there was no significant interaction between cage shape and energy regulation. 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. In the 6‐ to 12‐week period four dietary treatments were applied: a diet containing about 160 g crude protein (CP)/kg with or without 50 g dried poultry manure (DPM)/kg (diets 2 and 1 respectively) and a diet containing about 140 g CP/kg with or without 50 g DPM/kg (diets 4 and 3). In the 12‐ to 18‐week period two additional diets were fed: diets 1 and 3 supplemented with 10 g urea/kg (diets 5 and 6 respectively). Diets containing DPM were formulated to utilise the CP, energy, calcium and 50% of the phosphorus content of DPM.
3. Pullets fed on diets 1, 2 and 5 (high‐protein) were significantly heavier at 18 weeks than those fed on diets 3, 4 and 6 (low‐protein). In the laying period total estimated egg weight, food intake and conversion were significantly greater, and the age at first egg was significantly less (2.4 d).
4. Dietary DPM had no significant effect on the 18‐week body weight but food consumption was significantly less and conversion was significantly improved. There were no significant effects on subsequent laying performance. Dietary urea caused no significant effects on rearing or laying performance. 相似文献
Apart from a possible beneficial effect during the first few weeks of production, little increase in egg weight occurs when birds are fed on conventional rearing diets and then fed on laying diets containing linoleic acid in excess of requirement.
After depletion of linoleate reserves, dietary supplementation with linoleic acid significantly increases egg weight at any age.
The necessity of supplementing diets for laying hens with linoleic acid is discussed. 相似文献
In both experiments maximum egg production was obtained from the birds fed the high‐energy diet ad libitum. Restriction of the concentrated diet caused a significant reduction of body weight gain and a statistically insignificant fall in the total weight of egg product and in percentage production in both experiments.
Restriction of the concentrated diet caused improvements of 22 and 18 per cent in the efficiency of utilisation of metabolisable energy in experiments 1 and 2 respectively.
The data are discussed in relation to the relevant literature and the current cost of concentrated sources of energy. 相似文献
It was found that the best performance was obtained with hens fed the control diet. Gross energetic efficiency of egg production was slightly lower in the birds fed the diets containing arachis or sucrose. It appeared that the lower efficiency was due to the higher mean body weight of birds on these diets. Egg size was significantly increased by feeding the diet containing arachis oil.
Performance of hens given diets containing tallow was unsatisfactory. For each diet egg production was significantly less than that recorded for the control diet and the gross energetic efficiency of egg production was much lower than that on the control diet. 相似文献
2. The diet containing no cereal and 225 g dried poultry manure/kg (diet F) caused a severe reduction in performance and was discontinued at 27 weeks of age; the other treatments were continued until 48 weeks of age.
3. In the case of medium hybrids, rate of lay (number of eggs/100 hen d) was similar with diets A, B and C and about 2 percentage points lower with diets D and E; egg output (g per hen d) tended to decrease slightly as dietary cereal concentration decreased.
4. In the case of light hybrids, rate of lay was about 5 percentage points lower with diets B, C and D and about 13 percentage points lower with diet E than with diet A.
5. Mortality was similar on each diet.
6. The effect of diet on live‐weight gain was inconsistent and statistically not significant. 相似文献
2. The inclusion of AA improved egg production, food intake and efficiency of utilisation, and decreased the cost of food per kg egg. The addition of 400 mg AA/kg diet gave the most efficient performance.
3. Palm oil inclusion reduced the effect of heat stress and increased egg production, egg weight, food intake and efficiency of utilisation.
4. When 200 mg AA and 50 g palm oil/kg were used, additive responses were obtained with further improvements in egg production, food cost and efficiency.
5. Ascorbic acid and palm oil when fed alone or in combination reduced the incidence of cracked eggs.
6. Thus, 400 mg ascorbic acid/kg of diet, 50 g palm oil or 200 mg AA plus 50 g palm oil/kg diet ameliorated the effects of heat stress in laying hens. 相似文献
2. Final body weight of the force‐fed birds was significantly greater than of the other groups. Egg number and weight were significantly reduced as food intake decreased.
3. Liver weight per unit body weight was significantly increased and oviduct and ovary weights/kg body weight were significantly reduced by force‐feeding. As food intake decreased kidney and gizzard weights per unit body weight were significantly increased.
4. The concentrations and total contents of Cu and Zn in liver were significantly increased in the ad libitum and force‐fed groups.
5. Force‐feeding CuSO4‐supplemented diets, which eliminated difference in food intake, confirmed that CuSO4 per se affected tissue weights and mineral concentrations as distinct from effects due to the reduced food intake associated with increasing dietary CuSO4. 相似文献
2. Egg production was reduced in hens fed on diets containing HFM owing to a deficiency in lysine, methionine and tryptophan.
3. Supplementation of the diet containing HFM with 3'0 g lysine (as L‐lysine HC1), 0.7g DL‐methionine and 0.5g L‐tryptophan per kilogram, resulted in a daily egg mass output similar to that achieved with a conventional layers’ diet. 相似文献
2. During the 12-week experimental period, a total of 72 laying hens aged 52 weeks were randomly distributed among 6 experimental groups. Each experimental group contained 4 replicates, each with three birds. The experiment was a randomised design consisting of a 3 × 2 factorial arrangement, with three levels of wheat substitution and two levels of enzyme (xylanase: 1500.00 U/kg, β-glucanase: 100 000 U/kg, cellulase: 1 000 000 U/kg, α-amylase: 160 000 U/kg) inclusion in the diet. Wheat replaced 0, 50, or 100% of maize with or without 1.0 g/kg enzyme supplementation in iso-nitrogenous and iso-caloric experimental diets.
3. Body weight, egg production, egg weight, egg mass, eggshell thickness, and the feed conversion ratio were adversely affected by the wheat-based diet. The eggshell quality parameters decreased with enzyme supplementation to the diet.
4. Wheat-based diets adversely affected calcium and phosphorus concentrations in the tibia, but the addition of the enzymes to the wheat-based diet prevented the negative effects of wheat-based diets on tibia mineralisation in laying hens. The wheat-based diets tended to reduce plasma mineral contents, and the addition of enzymes tended to affect plasma minerals and biomechanical properties of the tibia positively in laying hens.
5. These results indicate that wheat-based diets in aged laying hens adversely affected the mineral metabolism compared with maize-based diets, and the negative effects of wheat on bone mineralisation can be prevented by enzyme supplementation to the diets in laying hens. 相似文献
2. A combination of 3 growing climates, 3 laying climates (temperate, hot dry, hot humid), and 2 dietary energy concentrations (10.03 and 11.70 MJ ME/kg with protein concentrations proportional to energy) were tested for 46 weeks using 432 point‐of‐lay pullets.
3. Both growing and laying climates significantly affected most traits measured during the laying period. The patterns of egg production showed good persistency in all environments and differences observed reduced with age.
4. The difference between the high and low energy intake reduced at high ambient temperatures. Feeding low energy diets did not affect mean age at first egg, rate of lay or the egg output in the hot dry environment, nor egg weight in either hot dry or hot humid climates. Rather, feeding low energy diets resulted in improved body weight change in all 3 laying environments.
5. The growing climate and diet interacted significandy on body weight change, while highly significant interactions between laying climate and diet occurred on rate of lay, food and energy intake and egg weight during the laying period. 相似文献
2. Plasma variables were measured during lay. End‐of‐lay trabecular and medullary bone volumes in the proximal tarsometatarsus and free thoracic vertebra were measured by histomorphometry.
3. The majority of Hisex hens were considered to be osteoporotic by the end of lay. In contrast, none of the J‐line were osteoporotic.
4. None of the nutritional treatments affected trabecular bone volumes. Medullary bone volumes were increased significantly by feeding oystershell or fluoride.
5. There was no phenotypic correlation between egg production and trabecular bone volume in the Hisex hens.
6. The experiment provided evidence that osteoporosis in laying hens, as assessed by trabecular bone volumes, is not caused by calcium deficiency and could not be prevented by any of the nutritional treatments studied. 相似文献
2. The use of low energy diets (10.5 to 11.3 MJ ME/kg) decreased egg production in both seasons, but pelleting diets improved egg production and egg weight in summer. Egg weight was not affected by energy density in winter, but decreased in the summer when energy density increased.
3. In winter, food consumption was not affected by the dietary ME, while in summer food consumption increased when the dietary ME increased. Therefore, energy intake was not the same at all energy densities, but tended to increase as the energy density increased.
4. In summer, pelleting improved food efficiency and egg production and increased water consumption and the ratio of water to food intake. Water intake and water: food ratio decreased with increasing dietary energy concentration. 相似文献
2. Body weight gain, and the efficiency of food conversion were improved when the diet contained 50 g DPM/kg but higher rates of inclusion (100 or 150 g/kg) depressed growth.
3. Birds fed on diets containing 50 g DPM/kg yielded meat of comparable quality to those fed on the control diet whereas those fed on diets containing more DPM yielded meat containing more fat and less water.
4. The percentage moisture in the meat was inversely related to the lipid content.
5. Nitrogen retention was comparable in all groups. 相似文献
2. Egg weight was poor with the low fat basal diet but increased in relation to the amounts of maize oil (4 and 30 g/kg) included in the diet.
3. With a diet containing 30 g olive oil/kg, egg weight was similar to that obtained with the diet containing the same amount of maize oil.
4. Rearing the birds on diets containing low or moderate amounts of linoleic acid did not affect the response to fatty acid content of the layer's diet.
5. It is concluded that the requirement of the laying hen for linoleic add is not higher than 9 g/kg but that egg weight does respond to higher dietary amounts of readily absorbable fatty acids. 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. Increases in food consumption were accompanied by increases in egg production.
3. The food required per dozen eggs was improved by up to 100 g dietary DPM/kg and variation in the sizes of eggs laid depended on the hybrid.
4. Concentrations of DPM up to 100 g/kg did not affect the water‐soluble nitrogen content of the egg but the crude albumen nitrogen content was depressed at concentrations of 80 g/kg or above.
5. Feeding DPM to laying pullets depressed body weight. 相似文献
The medium hybrids ate more and were heavier than the lighter hybrids at all stages. More eggs were laid by the light than by the medium hybrids but the latter laid larger eggs so that the total weight of eggs laid did not differ significantly between the two groups.
Medium hybrids given a low‐energy chick diet laid more eggs subsequently than those given a high‐energy chick diet, while the opposite result was obtained for the light hybrids.
Birds given a low‐energy rearing diet were lighter at 16 weeks and subsequently laid more eggs than birds reared on a high‐energy diet.
During the first part of the laying period consumption of the low‐energy diet was greater than that of the high‐energy diet, but the level and efficiency of egg production were the same for both dietary treatments. Mortality during lay was not significantly affected by dietary treatment or breed. 相似文献
2. A tryptophan‐limiting protein mixture was used and by dilution seven dietary protein contents were produced, supplying from 0.84 to 1–92 g tryptophan/kg diet. The diet of lowest protein content was also sup‐lemented with free tryptophan. These diets were fed in experiments using 24 groups of 72 pullets at 63 to 73 weeks and 45 groups of 21 hens at 97 to 106 weeks.
3. The relationship between egg output and tryptophan intake was the same in moulted hens as in young pullets, but pullets of 63 to 73 weeks of age yielded a different response curve; more tryptophan being needed for a given egg output.
4. It is concluded that tryptophan required, per day, does not decrease during the first laying year, despite a decrease in rate of egg output. 相似文献