2. In two experiments, newly hatched hybrid and Brown Leghorn chicks were reared in isolation and in small groups of different sizes, and their growth, food intake and feeding activity were measured for several eeks.
3. Initially, chicks of both strains grew faster when they were grouped than when they were in isolation, as a result of a more efficient conversion of food rather than as a result of increased consumption.
4. Later, chicks in the largest groups converted their food less efficiently, possibly because of increased disturbance.
5. From 6 to 12 weeks, when the chicks were in larger cages, growth rate was not affected by group size, but food intake and food conversion were affected differently in the two strains.
6. In general, the isolated chicks ate about the same amount as the grouped ones, and it is doubtful whether social facilitation of feeding occurred at all in these experiments. 相似文献
2. Chicks showed no significant alteration of their feeding behaviour in response to raising pen walls in the rearing facility from 30 to 60 cm.
3. Further analysis on a different set of birds revealed consistent short term individual differences in the frequency of feeding and non‐feeding pecks.
4. There were significant pen effects on behaviour suggesting the possible development of a pen ‘culture’ of pecking behaviour.
5. Pecking behaviours in 26 to 33 d‐old chicks, with the exception of drinking, were generally negatively correlated, so any non‐food pecking by a chick was generally associated with fewer pecks targeted at food.
6. By the age of two months chicks were pecking at food on the floor to a far greater extent than at any food presented in food trays. 相似文献
2. Growth rate, food intake, food utilisation and proportion of dietary nitrogen retained were much poorer in chicks receiving salseed meal.
3. The chicks receiving salseed meal developed pathological lesions in liver and kidney.
4. The red blood cell count, white blood cell count, haemoglobin concentration and packed cell volume of the chicks receiving salseed meal were lower than those of chicks receiving maize.
5. The apparent metabolisable energy value of salseed meal was determined as 6.83 MJ/kg. 相似文献
2. For both cockerels and chicks, the digestibility and TMEn of semipurified starches from triticale were higher than those from beans. Starch digestibilities of triticales (range 99.1 to 97.7%), of semipurified starches from triticales (range 96.5 to 89.9%) and from field beans (range 75.4 to 71.6%) were similar for both cockerels and chicks.
3. The addition of NT‐hulls improved, in general, the digestibility of semipurified starches for both chicks and cockerels, which suggests that fibre improves the digestion of semipurified starches.
4. The effects of tannins of T‐hulls on semipurified starch from beans and from triticale were different. Tannins always decreased the digestibility and TMEn of semipurified starch from field beans but only decreased the digestibility and TMEn of semipurified starch from triticale when fed to chicks, but not when fed to cockerels.
5. The addition of tannin extract always decreased the digestibility of semipurified starches by a greater amount than T‐hulls, which supports the idea that the effect of tannins depends on the quantity of tannin ingested. 相似文献
2. Creatine supplementation of AJB diets markedly enhanced the efficiencies of food and nitrogen utilisation of chicks, restoring these indices to control values. The improvement in nitrogen utilisation was enhanced further on providing creatine with a mixture of 2‐aminoiso‐butyric acid, arginine and lysine.
3. Potassium acetate induced striking improvements in the nitrogen retention efficiencies of chicks fed on AJB diets.
4. Liver weights, as a proportion of body weight, generally increased on feeding AJB diets, the effects being marked with the AJB diet supplemented with arginine and lysine.
5. Hepatic urea concentrations were elevated in all groups receiving AJB. Canavanine, a toxic amino acid component of AJB, could not be detected in acid hydrolysates of livers from chicks fed this legume.
6. Temperature and the volumes of water employed in the preparation of AJB are important determinants of its nutritional value. 相似文献
2. There was a linear decrease in body weight and efficiency of food utilisation with each percentage increase in DPM.
3. The amount of dried droppings recovered as a percentage of food consumed was proportional to the amount of DPM included in the diet and remained fairly constant during the recycling.
4. Body weights and efficiency of food utilisation were substantially the same during the first three recycling periods but declined significantly during the fourth period.
5. Mortality was negligible and all chicks appeared healthy and vigorous.
6. Chicks fed on 10% DPM in an isocaloric and isonitrogenous (protein‐N) diet grew and utilised food as well as those fed on the basal diet; chicks fed on 20% DPM did not consume enough to meet their requirements. 相似文献
2. Food presented in bowls was largely ignored whereas food scattered on the floor was readily taken.
3. A colour preference test showed that green was the preferred colour.
3 Reprint requests to Dr Deeming at Hangland Farm Ostriches Ltd, Upper Wardington, Banbury, Oxon OX 17 1SU, England 相似文献
2. Chicks on treatments 1 and 2 were fed continuously while those on treatments 3 and 4 were fed during the day (from 06.00 h to 18.00 h) and night (from 18.00 h to 06.00 h) respectively. Chicks on treatment 1 received only natural light during the day, while those on treatments 2, 3 and 4 received supplementary lighting during the night in addition to natural light during the day.
3. Food consumption by birds on treatment 2 was significantly higher at 56 days of age, followed by birds on treatments 1, 4 and 3.
4. The pattern of body weight gains was similar to the order of food consumption.
5. Efficiency of food utilisation was poorest for birds on treatment 2.
6. Mortality rates were not influenced significantly by the feeding regimen and lighting pattern.
7. Dressing percentage and proportion of abdominal fat were greatest for birds on treatment 2. 相似文献
2. Hens losing 0.30 of their initial body weight (BWL) produced more hatching eggs and chicks than those which lost 0.20 BW.
3. Hens fed on cracked grain produced fewest non‐hatching eggs, most chicks and the most efficient food utilisation.
4. The interactions showed that hens which lost 0.20 BW and were fed on layers ration produced most eggs. When number of chicks hatching was the criterion then hens losing 0.25 to 0.30 BW which were fed on cracked grain for 3 weeks gave the best performance. 相似文献
2. Stress attributable to fasting was not manifested through leucocytic alteration when food‐restricted chicks were supplemented with an adrenal blocking chemical, metyrapone.
3. Provision of metyrapone during the fasting period resulted in inferior compensatory growth during refeeding.
4. Exposure to high temperatures from 36 to 43 d of age did not cause an elevation in the heterophihlymphocyte (H/L) ratios of chicks that had eaten metyrapone‐treated food ad libitum during the neonatal stage.
5. During heat exposure, chicks that had been subjected to early 60% restriction with non‐metyrapone‐treated food had lower H/L ratios and improved resistance to marble spleen disease infection. 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. 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
2. Growth was significantly enhanced by regular handling in broilers and the females of the layer strains and gain : food ratios were generally greater in the handled birds.
3. There were no significant treatment effects on growth or gain : food ratios in males of the layer strains.
4. Males had higher relative weight gains and gain : food ratios than females. 相似文献
2. Birds reared on rice husk litter showed the greatest food consumption, greatest weight gain, best food conversion efficiency and scored highest in production number.
3. Survivability was also highest with rice husk group (94.4%) but differences in this variable were not thought to be attributable to types of litter.
4. Breast blisters were found only in birds reared on sand (8.3%).
5. It was concluded that rice husk is a suitable litter for rearing broilers on the floor, particularly in paddy‐growing countries. 相似文献
2. Commercial broiler chicks were fed from 7 to 49 d of age on 15 experimental diets which varied in their concentrations of tannins and animal fat (tallow), by the inclusion of different amounts of high and a low protein varieties of sorghum.
3. Substitution of a low tannin sorghum completely for maize did not have any significantly adverse effect on performance. Broiler chicks could tolerate up to 2.6 g tannin/kg above which their performance was reduced. Addition of tallow did not significantly affect broiler performance except at the highest tannin content and added fat intake, where weight gain and efficiency appeared to improve significantly. 相似文献
2. Data were analysed for species differences in food consumption, body weight, food utilisation, mortality and liver pathology.
3. There were no significant effects of aflatoxin in broiler and Leghorn chicks. Aflatoxin at 0.7 mg/kg decreased the body weight of turkey poults but tended to increase the growth rate of goslings. At 1 ‐4 mg aflatoxin/kg food consumption, body weight and weight gain of goslings were adversely affected.
4. Liver damage occurred in goslings and quail chicks at all inclusions of aflatoxin and was extensive at 2.1 mg/kg.
5. Poults and goslings appeared to be the most sensitive, quail were intermediate and domestic chicks were most resistant. 相似文献
2. Time of day of injection did not modify the response to corticosterone of 3‐week‐old chicks kept under natural daylight nor of 7‐week‐old broilers receiving additional illumination.
3. Pure White Rock chicks and Cornish x White Rock crossbred chicks responded similarly to corticosterone injections at 3 weeks of age.
4. Seven‐week‐old female birds treated with corticosterone had significantly larger abdominal fat pads than similarly treated males.
5. Corticosterone injection was more effective in increasing the proportion of liver fat in 7‐week‐old birds than in 3‐week‐old ?hicks.
6. The increased amount of abdominal and liver fat due to corticosterone injections administered at 3 weeks of age disappeared after 3 weeks, but growth depression was still evident. 相似文献
2. Groundnut meal, groundnut meal adjusted with indispensable amino acids or sesame meal supplied the dietary CP at 180 g/kg diet. Increments of lysine (1.5 g/kg diet) were added to each of these diets.
3. The gain, food intake and food efficiency responses of broiler chicks were analysed using a quadratic equation and a two‐slope method. An estimate of lysine requirements was also obtained from a survey of college students.
4. The different methods produced widely different estimates of lysine requirement.
5. The average lysine requirement was estimated at 50.1 g lysine/kg CP for groundnut meal, 61.7 for adjusted groundnut meal and 54.9 for sesame meal.
6. Reasons for the effect of statistical analysis and protein source on lysine requirement are discussed. 相似文献
2. Because the traditional method of determination of droppings digestibility coefficients of nitrogen may lead to systematic errors in estimating the feeding value of foodstuffs, a method is proposed to determine the ileal digestibility coefficients. The ileal method is compared with the droppings method for a mixed food and for two foodstuffs: wheat and solvent‐extracted soyabean meal.
3. Birds selected for efficient food conversion showed distinctly higher digestibility coefficients for all nutrients than birds selected for high growth potential or birds from a commercial strain.
4. The influence of age on digestibility coefficients was not consistent.
5. Female birds showed digestibility coefficients which were, in general, 3% higher than those of male chickens.
6. Interactions between genotype and sex and between genotype and age for energy metabolisability were the only interactions observed for digestibility measurements.
7. The method of determination influenced the amino acid digestibility coefficients of the mixed food and the relative feeding values of wheat and soyabean meal.
8. It is important to use well defined animals (genotype, sex, age) in evaluating foodstuffs.
9. The preferred method for determination of digestibility coefficients of nitrogen and amino acids is based on ileal sampling, although the differences in amino acid digestibility coefficients were small between methods. 相似文献
The fats concerned were soyabean oil, soyabean soapstock, maize oil, lard, grease and tallow. Their effect was studied by using regression analyses.
It was found that the addition of fat, both animal fats and vegetable oils, diminishes food intake. The food intake decreases significantly with rising percentages of fat according to a linear function. No differences in effect between various fats could be demonstrated.
The incorporation of various fats improves the weight gain, although the increase was not related to the amount of fat added. The improvement in weight gain differs from one fat to an other.
The addition of fats improves efficiency of food conversion, but varies according to the kind of fat. Here the improvement is correlated with the level of fat added.
The difference in improvement of food conversion can be only partially explained by differences in absorbability and metabolisable energy of the fats.
It is concluded that certain fats ameliorate the efficiency of food conversion and, in some cases, weight gain to a higher degree as may be expected from their metabolisable energy content. It might be possible that some fats possess one or more factors which improve the efficiency of metabolisable energy or exert a protein anabolic action. 相似文献