2. As a proportion, mortality was 0.5 in turkeys fed ad libitum and 0.1 in those which were restricted. There were significantly fewer leg problems in the birds undergoing food restriction.
3. Sexual maturity was delayed 4 weeks by food restriction although semen quality was similar to that in ad libitum‐fed birds.
4. Individual semen production was lower after food restriction but, because mortality and food consumption were also lower, semen production per male housed and semen production per kg of food eaten were proportionally 0.30 and 0.32 greater in restricted‐compared with ad libitum‐fed turkeys.
5. Useable quantities of good quality semen were obtained from ad libitum‐fed turkeys at 23 weeks of age.
6. A short photoperiod (7L:17D) from 10 to 18 weeks of age in ad libitum‐fed turkeys produced more rapid development of normal semen production compared with turkeys given a longer photoperiod (14L:10D). 相似文献
2. It was fed at 16 weeks of age to five separate groups (groups 2 to 6) each of 50 to 60 birds.
3. Group 2 was fed on a normal layers’ diet at 23 weeks of age, group 3 at 27 weeks, group 4 at 31 weeks, group 5 at 35 weeks and group 6 at 55 weeks while the control group (group 1) of similar size to groups 2 to 6 was subjected to a normal commercial treatment for laying stock.
4. In all the experimental groups the onset of sexual maturity occurred normally, but only one or two eggs were laid before laying ceased under the influence of the treatment.
5. Laying re‐started when the hens were fed on a normal diet and production rapidly rose to a high level.
6. Groups 1, 2 and 3 differed little in the total number of eggs produced up to 72 weeks of age.
7. In all experimental groups there were fewer very small, small and medium eggs than in the control group.
8. It is suggested that the use of a low‐calcium diet before the onset of lay may have advantages which could be exploited on a commercial scale. 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
2. Water intake was consistently higher in the 0.25, 0.40 and commercial restriction treatments.
3. There was a negative curvilinear relationship at each age between body weight and the heterophil‐lymphocyte ratio and plasma corticosterone concentration.
4. There was a positive relationship between the plasma concentration of creatine kinase and body weight at 12 and 18 weeks of age. The relationships between body weight and the plasma activity of alkaline phosphatase and aspartate transaminase changed with age and there were no differences between treatments for lactate dehydrogenase.
5. The time spent resting increased with body weight at each age. The relationship between time spent preening and body weight changed with age whereas that for oral activities was similar among restricted birds at 6, and among all treatments at 12 weeks of age. At 18 weeks there was an increase in oral activities with decreasing body weight.
6. Fearfulness was positively related to body weight. The response of the comb to phytohaemagglutinin injection was similar in all treatments and the antibody titre to injections of sheep red blood cells was curvilinear.
7. A principal components analysis of all measured traits at 6, 12 and 18 weeks of age was conducted. Most of the variables were redundant but at least one from each of the different classes of welfare indices was retained at 6 and 12 weeks of age.
8. It was concluded that a body weight during rearing in the range of 0.5 to 0.85 of ad libitum might provide for optimum welfare of broiler breeder females. 相似文献
2. Varying mixtures of dried poultry manure, dried grass, dried potato meal, poultry offal meal and tallow were substituted for the cereal portion, so that calculated metabolisable energy values and methionine and lysine concentrations were constant within each protein series.
3. Within the 150 g protein/kg series, body weight at 20 weeks of age was similar for diets containing 800, 600 and 300 g/kg cereal whereas with the cereal‐free diet body weight was depressed by 10%; with the latter diet sexual maturity was also delayed by nearly 4 d though subsequent egg production was unimpaired.
4. Within the 100 g protein/kg series, body weight at 20 weeks of age and subsequent egg production, calculated either to a fixed age or for a given time spent laying, were depressed by diets containing 300 or 0 g cereal/kg, compared with diets containing 800 or 600 g/kg.
5. Dietary concentrations of dried poultry manure up to 250 g/kg had no effect on mortality. 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. Plasma VLDL plus LDL triglyceride concentrations were similar in males and females and only slightly higher in birds fed on the high‐fat diet. Concentrations at 3 weeks were similar to those at 7 weeks.
3. Body fat content was correlated more closely with plasma VLDL plus LDL triglyceride measured at 7 weeks than at 3 weeks.
4. Phenotypic correlations between body fat content and plasma VLDL plus LDL triglyceride concentrations at 7 weeks were 0.47 and 0.43 for males and females respectively fed on the high‐fat diet and 0.70 and 0.60 for males and females fed on the low‐fat diet.
5. Phenotypic correlations between body fat content and measurements with an abdominal caliper were 0.35 and 0.49 in birds fed on the high‐ and low‐fat diets respectively.
6. A possible procedure for selecting for leanness in broiler breeding programmes on the basis of measurements of plasma VLDL plus LDL triglycerides is discussed. 相似文献
2. Extrusion cooking of rice bran resulted, in improved chick weight gain and food efficiency for the first two weeks of feeding, but this advantage was lost by the end of the feeding period.
3. Addition of 10 g calcium/kg to the stabilised rice bran diet prevented the decline in performance after two weeks of age, and birds fed on this diet continued to gain at an increasing rate until the end of the experiment.
4. Calcium supplementation of stabilised rice bran diets produced significantly greater gains and superior food utilisation compared to stabilised rice bran diets without added calcium.
5. Calcium supplementation did not affect weight gain of chicks fed on diets containing raw rice bran.
6. Taste panel evaluation of meat from birds fed on diets containing raw rice bran, stabilised rice bran, or no rice bran indicated a significant preference in only one combination tested. Any ‘off flavour could not be related to dietary treatment. 相似文献
2. Controls grew best and matured first: maturation was delayed by about 2.lb5 d with each 100 g reduction in body weight at 20 weeks. Body weights at 20 weeks, taking controls as 100, were 50, 70, 78 and 73 for B, C, D and E applied from 8 weeks and 72, 87, 87 and 86 when applied from 12 weeks. Lower‐leg length was increased by mineral but not by vitamin supplementation. Birds in floor pens grew faster than those in cages.
3. Mortality was nearly 30% in pullets receiving diet B from 8 to 20 weeks of age: feeding the diet from 12 weeks, or supplementing it with minerals (C), reduced mortality to 4% or less, but vitamins had no beneficial effect.
4. Conventionally fed birds laid more eggs than other groups. 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. There were no differences in early fertility between males weighing 3–0 or 3–5 kg at the start of the mating period, or between males gaining 1.0 or 1.5 kg body weight from mating to 60 weeks of age.
3. There were no differences in fertility between males fed on the two diets differing in crude protein content.
4. One strain of male had lower fertility than the other and this was associated with a greater weight of breast muscle, lower frequency of observed copulations and a higher number of incompleted matings.
5. Sexual activity declined and the number of spermatozoa trapped on the perivitelline membrane increased with age.
6. There were no differences among the treatments in the prevalence of musculo‐skeletal lesions (destructive cartilage loss). As a proportion destructive cartilage loss occurred in 0‐67 of the males at 66 weeks of age. Degeneration of the antitrochanter was present in 3 of 50 females examined and a cartilage flap in the medial condyle of the tibiotarsus occurred in 15 of these birds.
7. Beak lesions were the most important cause of male culling which averaged 0–24 as a proportion of the males at the start of the experiment. 相似文献
2. At 8 weeks of age, birds receiving 50 and 75 g sand/kg diet were significantly heavier than those receiving the basal diet and 100 g sand/kg diet.
3. Birds receiving 0 and 100 g sand/kg diet consumed similar quantities of basal diet and yielded similar corrected food:gain ratios.
4. Dietary dilution with sand had no significant effect on mortality, apparent carcase yield, preventriculus weight, gizzard weight and intestinal length. Crop weights were significantly greater in birds given 100 g sand/kg diet to the age of 4 weeks.
5. The litter moisture content was significantly less in pens containing birds receiving 75 or 100 g sand/kg diet after 5 weeks of age. 相似文献
Both methods of nutrient restriction reduced intake to 20 weeks of age. From 1 d to 60 weeks of age total food intake was reduced in proportion to the degree of restriction applied during the growing stage.
Sexual maturity was delayed by both methods of restriction, though low‐lysine diets produced a greater delay than quantitative restriction. Production of total eggs and of settable eggs was increased by both quantitative food restrictions and by the least severe of the lysine‐deficient diets. Following quantitative restriction egg size and fertility were both improved, but these advantages were not obtained by lysine restriction.
Mortality and culling were mainly influenced by a high incidence of “rupture of the gastrocnemius tendon “ which occurred exclusively in pullets fed lysine‐deficient diets during rearing.
It is concluded that quantitative restriction is to be preferred because of its advantageous effects on egg weight, rate of lay and fertility, and because it avoids the high mortality rate found with severe lysine restriction. 相似文献
2. Expressed per unit body weight, food and metabolisable energy (ME) intake and weight gain decreased between 2 and 3 weeks of age, but remained constant thereafter.
3. No differences were observed between sexes for any variable measured. Efficiency of utilisation of ME for energy retention was only 0.33. This was mainly because the majority of energy was retained as protein tissue.
4. Nitrogen (N) retention (g/d) increased with increasing dietary N intake but when expressed as a proportion of N intake, declined from 0.46 at 2 weeks to 0.33 at 4 weeks. Fat retention increased substantially during week 4.
5. Carcass analyses showed that fat, protein and ash were higher for quail at 5 weeks than at 2 weeks of age. At 5 weeks carcass fat was only 60 g/kg. 相似文献
2. High DEB diets contained soya as the main protein source whereas low DEB diets did not contain soya bean meal. Diets were formulated to be iso-caloric and iso-nitrogenous in each of 3 successive 4-week phases following recommended dietary compositions. DEB concentrations were 330, 290 and 250 mEq/kg in high DEB diets and 230, 200 and 180 mEq/kg in low DEB diets.
3. Litter moisture and mean FPD score were higher in turkeys fed on high DEB diets compared with low DEB diets whereas there was no difference between maize and wheat.
4. Food intake was similar and body weight was lower after litter moisture was artificially raised in the wet compared with the dry litter treatment and there was no interaction with dietary composition.
5. Mean body weight and feed intake were higher in turkeys fed on wheat compared with maize and in high DEB compared with low DEB diets at 12 weeks of age.
6. Lowering dietary DEB for turkeys may improve litter moisture and lower the prevalence of FPD in commercial turkey flocks. 相似文献
There was a higher mortality in the pullets fed a ration containing 0.53 per cent lysine during the growing period. The mortality in the group fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age was the same as that of the control. There were no differences in mortality during the laying season that could be related to methods of rearing the pullets.
During the laying season, the highest rate of lay was obtained from hens which had been fed the ration containing 0.42 per cent lysine from 7 to 22 weeks of age. Hens fed on the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks of age showed no improvement in rate of lay as compared with controls.
Hens fed the ration containing 0.42 per cent lysine from 7 to 22 weeks laid fewer small eggs at the beginning of the laying season than did hens receiving adequate amounts of lysine throughout or fed the ration containing 0.53 per cent lysine from o to 4, 8 or 12 weeks. The hens fed the latter ration laid smaller eggs throughout the laying season.
No differences were found between the fertility, hatchability or embryonic mortality of eggs obtained from hens fed on lysine deficient diets during growth and those fed on diets adequate in lysine. 相似文献
2. Adding 5 μg 1,25‐DHCC/kg to a diet containing 12 g calcium/kg was more effective than early food restriction or meal feeding in preventing leg abnormalities but was found to cause a growth depression.
3. The second experiment, which had a factorial design, with diets containing 7.5, 100 and 12.5 g calcium and 0, 2.0, 3.5 and 5.0 μg 1,25‐DHCC/kg, showed linear and quadratic interactions between these dietary factors. Diets with higher concentrations of both 1,25‐DHCC and calcium resulted in growth depression associated with hypercalcaemia.
4. The incidence of tibial dyschondroplasia (TD) at 3 weeks of age was highest with the basal diet containing 7.5 g calcium/kg and was markedly reduced by addition of 1,25‐DHCC and/or calcium. The incidence was very low or non‐existent when 1,25‐DHCC was fed at 3–5 μg/kg or greater.
5. Feeding 5 μg/kg 1,25‐DHCC had no effect on plasma 1,25‐DHCC concentrations, although at the higher dietary calcium contents plasma concentrations of 25‐hydroxy‐ and 24,25‐dihydroxy‐cholecalciferol were lower in those birds fed 1,25‐DHCC.
6. It is concluded that 1,25‐DHCC is most effective in preventing TD without accompanying growth depression when it is fed in conjunction with diets containing less than 10 g calcium/kg. 相似文献
2. Kidney damage was not observed in pullets reared on NC diets. For pullets fed on HC diets, strain A developed significantly greater kidney asymmetry, a higher incidence of gross kidney damage and a higher incidence of uroliths than strain B.
3. Supplementing the HC diet with 6 g/kg DL‐methionine significantly reduced the incidence of calcium‐induced gross kidney damage and urolith formation in both strains. Ammonium sulphate (5.3 g/kg) was significantly more effective than dl‐methionine in reducing calcium‐induced kidney damage.
4. Neither dl‐methionine nor ammonium sulphate caused a measurable metabolic acidosis. Neither supplement consistently affected water consumption or manure moisture. 相似文献
2. Dietary rapeseed had no effect on the onset of lay when fed from 17 weeks of age but caused a delay when fed from 10 weeks of age: changing to a control soyabean diet for the laying period resulted in normal egg production.
3. Diets containing B. napus but not B. campestris consistently depressed egg production and reduced egg weight in one experiment. Mustard seed meal did not affect performance.
4. Significant number of eggs with a “fishy” taint were laid by brown‐egged birds fed on a diet containing rapeseed.
5. Thyroids of birds fed on rapeseed meal diets during the laying period were significantly heavier than those of birds fed on diets containing mustard seed or soyabean.
6. The enlargement of the thyroid gland is probably related to the oxazolidinethione content of the rapeseed. 相似文献
2. The proportion of males producing semen declined with increasing dietary crude protein content and resulted in a significant decrease in total semen volume and spermatozoa production.
3. The relationship between the concentration of spermatozoa in the semen and dietary crude protein was negative but trivial. There were no relationships between dietary crude protein content and semen volume or the metabolic activity of spermatozoa.
4. The metabolic activity of spermatozoa was lower at 25 compared with 37 weeks of age.
5. The proportion of males giving semen peaked between 32 and 42 weeks of age. The relationship between age and semen volume and concentration of spermatozoa was negative and linear.
6. Blood plasma uric acid concentration increased linearly above 106 g CP/kg and males on 400 g CP/kg developed articular gout and had to be destroyed. 相似文献