Effect of low protein diets for growing Leghorn pullets upon subsequent laying performance

An experiment was conducted with White Leghorn pullets to study the effect on laying performance of dietary protein content and amino acid supplementation during the growing period. From 0 to 6 weeks of age birds fed on diets containing either 149 g protein/kg supplemented with methionine and lysine or 182 g protein/kg grew faster than those fed on a diet containing 149 g protein/kg alone. However, only those fed on the supplemented diet utilised their food more efficiently. From 7 to 20 weeks of age neither body weight gain nor food utilisation was affected by the dietary protein content. Pullets fed the low protein diet supplemented with 2 g methionine/kg and 2.5 g lysine/kg during the period of 0 to 6 weeks of age had significantly better egg production than birds fed the low protein diet alone. The dietary protein content during 7 to 20 weeks of age did not influence subsequent egg production.     

The performance of laying hens fed on rearing and laying diets containing urea

In an experiment using 2880 light hybrid pullets the effect of urea on laying performance has been assessed. Birds received one of three low‐protein rearing diets from 7–20 weeks of age. The control rearing diet, containing 11.5% crude protein, was compared with two diets containing 13.2% crude protein, one in which the protein was from conventional sources and the other containing 11.5% conventional protein and urea equivalent to 1.7% crude protein. At 20 weeks birds were allocated to one of two laying diets formulated to meet essential amino acid requirements. Half the birds from each rearing treatment received a low‐protein diet (14.7%) and the remaining birds received a 16.4% protein diet which included urea equivalent to 1.7% crude protein. Laying performance was recorded for the next 30 weeks.

Body weights of birds fed on the urea‐containing rearing diet were similar to those of birds fed on the control diet (1.22 kg) and less than those on the 13.2% protein diet (1.29 kg). Urea in the laying diet caused a 2% increase in egg production and tended to cause an improved food conversion efficiency. In contrast, a 3.5% less efficient food conversion was found during laying in birds which had received urea during rearing, compared with birds which had received the low‐protein rearing diet. Birds receiving the 13.2% protein diet, containing no urea, during rearing laid smaller eggs than birds fed on the 11.2% protein rearing diet. A high mortality rate occurred during laying due to lymphoid leucosis but no differences between treatments were found.     

Effect of feeding diets based on coarse maize on productive performance,gizzard development and energy utilisation of laying hens

1. A total of 2200 White Leghorn layers were used to study the effect of feeding coarse maize on productive performance, gizzard weight, apparent metabolisable energy (AME) and egg quality parameters.

2. The experiment was a completely randomised design with 5 treatments, each being replicated 5 times (88 birds per replicate). Dietary treatments included a control diet with 600 g/kg of ground maize (6 mm sieve) and experimental diets with 150, 300, 450 or 600 g/kg coarse maize (10 mm sieve) replacing (w/w) ground maize. Diets, in mash form, were offered from 39 to 62 weeks of age.

3. Over the entire experimental period, dietary treatments had no effect on any of the production parameters, except on feed intake. A quadratic effect was observed for feed intake, where intake increased at 150 g/kg coarse maize inclusion. At higher inclusion levels of coarse maize, feed intake was similar to that of the control diet. But the differences in daily intake between dietary treatments were only around 1 g/bird and may not be of any biological significance.

4. Dietary treatments had no effect on gizzard weight, AME or egg quality.

5. The results indicate that coarse maize could completely replace maize in layer diets with no adverse effect on egg production, egg quality and dietary energy utilisation. In the current work, although the proportion of coarse particles (over 1 mm) increased with increasing inclusion levels of coarse maize, the differences in the percentage of particles above 1 mm between the fine control (0 g/kg coarse maize) and coarsest (600 g/kg coarse maize) diets was only 15%, and this may limit the value of the findings reported herein.     

The effects on rearing and subsequent laying performance of rearer diets containing two levels of protein and dried poultry manure or urea

1. Six hundred and seventy‐two light‐hybrid pullets aged 6 weeks were allocated to eight experimental treatments and cage‐reared to 18 weeks of age when they were transferred to single‐bird battery cages and fed on a common layer diet.

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.     

Some effects of changing protein levels during the pullet laying year

Three diets containing 12, 14 and 16 per cent crude protein were fed to laying pullets from 23 to 63 weeks of age. The laying year was divided into three periods of 10, 15 and 15 weeks to examine the effect of feeding these diets at different stages of lay. Eighteen treatments were used, representing all possible combinations of three diets in the first period, three diets in the second period and two diets (16 and 12 per cent) in the third period. Two groups of 75 pullets were allocated to each treatment.

In each period the diet had a significant effect on the rate of lay, egg output (g./day) showed a linear regression on protein intake. There was no indication that the amount of protein needed to maximise egg output was any less in one period than another, although the level of maximum output varied substantially as the year progressed.

Where the feeding of an inadequate level of protein in one period was followed by a higher level in the next, liveweight showed a marked recovery but there was little evidence of compensatory egg production. When the protein of the diet was reduced from 16 to 12 per cent, rate of lay fell sharply to a level below that of birds which had received the 12 per cent protein diet throughout.     

Free choice feeding of whole grains in meat-type pigeons: 1. effect on performance,carcass traits and organ development

1. The effects of 5 different feeding systems on the performance, carcass traits and organ development were studied in pigeon squabs.

2. The 5 treatments were (1) whole grains of maize, pea and wheat plus concentrate feed; (2)whole grains of maize and wheat plus concentrate feed (CWC); (3) whole grains of maize and pea plus concentrate feed; (4)whole grain of maize plus concentrate feed (CC); and (5) compound feed (CF).

3. Feed intake of parent pigeons increased significantly from 0 to 21 d and it was higher in the CF treatment. Body weight of squabs in the CWC treatment was the highest among the 5 treatments in 4 weeks. Body weight losses of parental pigeons during the rearing period were not significantly different among the 5 treatments.

4. Protein intake in CC and CWC treatments was lower than that of the other three treatments. The CWC treatment had the highest daily weight gain and the lowest feed conversion ratio. Treatments were statistically similar in the relative weight of carcass, breast and thigh. CF had the lower relative weight of abdominal fat.

5. Relative weight of gizzard in the CF treatment was significantly lower than that of CWC.

6. It was concluded that the application of free choice feeding of whole grains of maize and wheat plus concentrate feed increased the body weight of 28-d-old pigeon squabs and decreased the feed conversion rate of parent pigeons. This feeding strategy could be commercially interesting in meat-type pigeon production.

     

日粮中添加铜对产蛋鸡生产性能及蛋品质的影响

本试验选择五水硫酸铜作为饲料添加的铜源,以产蛋高峰期的海兰褐壳蛋鸡为试验动物,研究日粮中添加60mg/kg的铜对蛋鸡生产性能、蛋品质的影响。试验选取40周龄的海兰褐壳蛋鸡104只,设两个处理,每个处理4个重复,每个重复13只鸡。对照组饲喂基础日粮,试验组饲喂基础日粮 硫酸铜52mg/kg。试验结果表明:1)与对照组相比,试验组能够提高产蛋鸡的各项生产性能,日产蛋重、产蛋率、料蛋比、日采食量均有上升趋势(P>0.05)。2)与对照组相比,试验组的蛋形指数差异不显著(P>0.05),蛋壳厚度变厚(P>0.05),蛋白、蛋黄重以及蛋白蛋黄的比值差异不显著(P>0.05),破软蛋率下降(P>0.05)。     

A comparison of the effects of feeding treatments and lighting on age at first egg and subsequent laying performance and carcase composition of broiler breeder hens

The effects of the growth curve from 15 to 20 weeks, age at photostimulation and pattern of photostimulus on sexual maturity, egg production and egg weight were evaluated in two trials with broiler breeder females to 56 and 34 weeks of age (housed in litter pens and individually caged, respectively). Carcase composition and reproductive morphology of hens varying in laying efficiency were measured in the second trial. Trial 1: Four growth curves were applied from 15 to 20 weeks to pullets housed in litter pens. Birds were transferred from 8- to 10-h photoperiods at 20 or 24 weeks of age, followed by weekly increments of one hour to reach a 16-h final photoperiod. Lower-than-recommended body weights at 20 weeks significantly delayed sexual maturity, reduced peak rate of lay, total eggs and mean egg weight. However, double-yolked egg production was lower, resulting in non-significant differences in settable egg numbers between body weight treatments. Birds reared to the heaviest body weight exhibited a significantly advanced sexual maturity, but total egg numbers, peak rate of lay and mean egg weight were not significantly affected. However, the laying of more double-yolked eggs resulted in a decrease in the number of settable eggs. Delaying photostimulation to 24 weeks significantly retarded sexual maturity, reduced total and settable egg numbers, and increased mean egg weight. A tendency for fewer double-yolked eggs was observed. Trial 2: At 19 weeks, birds were selected from the 4 body weight categories in Trial 1 and moved to individual cages in 8 rooms. Five lighting programmes were applied. The pattern of photostimulation applied did not affect any of the production traits measured. At 34 weeks, 24 birds were selected for the analysis of reproductive morphology, presence of internal or multiple ovulations, and carcase composition. Eight hens showing an early age at first egg and regular egg production records, 8 birds showing erratic laying performance and 8 non-layers were killed for this purpose. There were no differences in carcase composition or reproductive morphology between these groups. No internal ovulations or double or multiple ovarian hierarchies were observed. The results presented confirm that broiler breeders do not require a lighting stimulus in order to initiate ovarian activity and that, where no lighting stimulus is given, body weight or feeding level plays a critical role in stimulating the birds to attain sexual maturity. However, when a lighting stimulus is given, factors such as body weight and body composition become relatively less important in regulating the age at sexual maturity.     

Phosphorus requirements of poultry. V. The effects during the subsequent laying year of feeding growing diets containing no animal protein or supplementary phosphorus

Pullets reared to 18 weeks of age on diets containing no feeding stuffs of animal origin and without phosphorus supplementation showed no significant difference in egg yield compared with similar pullets fed rearing diets containing animal protein and added phosphorus.

During the laying stage, diets in commercial use at this centre gave significantly higher egg yields, better average egg prices due to superior grading results and a higher margin over food cost than the same diets modified to conform with the nutrient recommendations of the National Research Council of America (1960).

Where the supplementary protein in both types of layers' diet was of vegetable origin, egg yield, food cost and margin of income over food cost were all significantly inferior to groups fed comparable diets containing supplementary protein of both vegetable and animal origin.

Soyabean meal and sunflower seed meal gave significantly poorer results when used in combination as the sole protein supplement compared with soyabean meal plus methionine.     

低豆粕日粮对产蛋鸡生产性能及蛋品质的影响

试验选用1 600只生产性能相同、体况良好的33周龄罗曼蛋种鸡,随机分为4组,在总蛋白质含量相同和满足必需氨基酸需要量的情况下,用价格较低的蛋白饲料取代蛋鸡日粮中豆粕,研究氨基酸平衡的低豆粕日粮对蛋种鸡生产性能和蛋品质的影响。结果表明:氨基酸平衡的低豆粕日粮对蛋鸡产蛋率、种蛋合格率、健雏率、蛋形指数、蛋比重、蛋壳厚度、哈氏单位等指标无显著影响(P>0.05),但当日粮中的豆粕含量降低8～15个百分点时,蛋种鸡的日平均蛋重、日采食量、受精率、孵化率等显著低于正常豆粕日粮(P<0.05),而考虑综合因素日粮中的豆粕含量降低8个百分点的第1组,与正常豆粕日粮相比,差异不显著(P>0.05),而且能降低饲料成本,可以提高蛋鸡养殖效益,具有实际意义。     

Wheat distillers grains in feedlot cattle diets: feeding behavior, growth performance, carcass characteristics, and blood metabolites

A study was conducted to evaluate feed intake, ADG, carcass quality, eating behavior, and blood metabolites in feedlot beef steers fed diets that varied in proportion of wheat dried distillers grains with solubles (DDGS) replacing barley grain or barley silage. Two hundred crossbred steers (BW = 489 ± 30 kg) were blocked by BW and randomly allotted to 20 pens (5 pens per treatment). Steers were fed 1 of 4 diets: control without DDGS (CON), 25% (25DDGS), 30% (30DDGS), or 35% (35DDGS) wheat DDGS (DM basis). The CON diet consisted of 15% barley silage and 85% barley-based concentrate; the 3 wheat DDGS diets were formulated by substituting 20% barley grain and 5, 10, or 15% silage, respectively, with 25, 30, or 35% wheat DDGS so that the 35DDGS diet contained no silage. The diets were formulated such that wheat DDGS was substituted for both barley grain and barley silage to evaluate whether wheat DDGS can be fed as a source of both energy and fiber in feedlot finishing diets. Dry matter intake of steers fed 25DDGS was greater (P < 0.01), but final BW, ADG, and G:F were not different compared with steers fed CON diet. Carcass characteristics and liver abscess score were not different between CON and 25DDGS. Steers fed 25DDGS had longer eating time (min/d; P < 0.01), greater meal frequency (P < 0.04), but a slower eating rate (P < 0.04). Replacing barley silage with increasing amounts of wheat DDGS (from 25DDGS to 35DDGS) linearly reduced (P < 0.01) DMI. Final BW, ADG, and G:F were not affected by increasing amounts of wheat DDGS. Carcass traits were not different, whereas liver abscess scores linearly (P < 0.01) increased as more barley silage was replaced by wheat DDGS. Eating time (min/d) and duration of each meal linearly (P < 0.02) decreased, whereas eating rate (min/g of DM) linearly (P < 0.01) increased with increasing replacement of barley silage. Blood urea N was doubled (P < 0.01) compared with CON by inclusion of wheat DDGS. Results indicate that wheat DDGS can be used effectively in feedlot diets, decreasing the need for barley grain or silage without negatively affecting growth performance and carcass characteristics. A reduction in the amount of roughage required to maintain growth performance is a potential advantage in feedlot operations because forage is costly and often of limited availability. Thus, DDGS can be a possible alternative as long as they are available and cost effective; however, increased incidence of liver abscess and increased N content of manure need to be considered when greater amounts of wheat DDGS are included in finishing diets.     

The laying performance of two strains of hens offered diets containing dried poultry manure during the laying stage

1. Light‐weight (Babcock B300) and medium‐weight (Warren‐SSL) hens were offered diets, containing 0, 100 or 200 g dried poultry manure (DPM) and 11.49, 11.12 or 10.83 MJ metabolisable energy/kg respectively, between 18 and 70 weeks of age. The true protein, metabolisable energy, calcium and phosphorus contents of the DPM, from caged layer hens, were used in the diet formulation.

2. The hen‐housed laying performance of hens offered the DPM‐containing diets was significantly better for number of eggs laid and total egg mass produced but the performance of the control groups was lower than would normally be expected of those stocks. The reason for the lower rate of lay and higher mortality of hens fed on the control diet was not identified. The amount of food consumed increased as the energy content of the diet decreased and the efficiency of food conversion (EFC) of the lightweight strain was reduced; there was no significant effect on the EFC of the medium‐weight hens.

3. The inclusion of DPM in the diets had no effect on albumen quality or on the incidence of hair‐cracked, cracked or broken eggs. However, with both strains of hens, shell weight and shell thickness were poorer when 100 or 200 g DPM/kg diets were fed.     

Lack of influence of pullet rearing conditions on the hen's performance

1. The influence of three aspects of the rearing conditions of pullets on their performance as adults was investigated.

2. The rearing conditions investigated were early acquaintance between birds, group size and stocking density.

3. The production characteristics measured were laying performance, feathering and foot condition.

4. No significant effect of rearing condition on the characteristics measured was found.

     

小麦基础日粮中添加酶制剂对蛋鸡生产性能和蛋品质的影响

玉米是最普遍的能量饲料，随着畜禽业的发展，对能量饲料—玉米的需求逐渐增大。我国饲料用玉米的年供应量远远不足，呈现较大的缺口，造成玉米的价格不断上涨，而我国小麦资源丰富，年产量在1亿t左右，其价格也比玉米的低。因此，研究开发小麦在饲料中的应用具有实际意义。小麦和玉米都属于能量饲料，其营养成分见表1。从表1看出，小麦粗蛋白质、氨基酸、钙、磷含量均高于玉米，能量为玉米的90%左右。但小麦中非淀粉多糖(NSP)的含量高，为玉米中的3倍。非淀粉多糖溶于水后可形成勃性凝胶，引起肠道内容物的勃稠度增加，阻碍营养物质的消…     

Efficacy of furazolidone in grower diets on subsequent performance of swine--a cooperative study

Nine experiments were conducted at three stations to evaluate the efficacy of furazolidone as a growth promoter in diets for young swine and to determine if an early growth response is maintained after the additive is withdrawn from the diet. A total of 528 pigs (24 replications, 132 pigs/treatment) initially averaging 12 kg body weight were fed a nonmedicated basal diet or a diet with 110 ppm furazolidone for 5 wk, 165 ppm furazolidone for 3 wk or 220 ppm furazolidone for 2 wk. After withdrawal of furazolidone, the basal diet was fed to the end of the test, at which time the pigs averaged 93 kg. During the initial 2-wk period, pigs fed furazolidone gained 15.4% faster (P less than .001) and required 8% less (P less than .001) feed per unit of gain than control pigs fed the nonmedicated diet. At 5 wk, pigs previously fed furazolidone gained 8.4% faster (P less than .001) and 4.5% more efficiently (P less than .001) than controls. By 10 wk, pigs previously fed furazolidone maintained a slight advantage in growth rate over controls (2.6%, P less than .10), but feed/gain responses were similar for the two groups. By the end of the experiment, the early growth response from furazolidone was completely lost. Although there were differences in growth responses among stations, the treatment response patterns were similar for each station, with no evidence of a treatment X station interaction.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effects of changes in photoperiod and feeding opportunity on the performance of two breeds of laying hen

1. ISA Brown and Shaver 288 hens, fed ad libitum, were given a 5‐h increase or a 2, 5 or 10‐h decrease in photoperiod at 215 d of age. Hens of both breeds were also maintained on constant 10, 13 or 18 h photoperiods. Other groups had their photoperiod increased from 8 to 13 h, or were held on constant days but had their access to food limited to 8 h per day.

2. Both breeds on ad libitum feeding exhibited curvilinear rate of lay and egg output, and linear food intake, responses to photoperiod change. Shaver hens reduced their egg output and rate of lay to a greater extent than ISA Brown hens when photoperiod was decreased.

3. In both breeds the beneficial effect on egg production of the 5‐h increase in photoperiod was less than the adverse effect of the 5‐h decrease.

4. The influence of light change per se generally had a greater effect on performance than the influence of feeding opportunity, but significant effects of changing feeding opportunity were demonstrated.

5. The reduction in mean rate of lay and egg output following a reduction in photoperiod was partly caused by some birds ceasing lay, but all birds showed some decrease in both variates     

The effect of varying flock size on the development and subsequent laying performance of floor‐reared pullets

Light‐weight, hybrid pullets were reared on litter in flocks of 400, 800 and 1200 birds per pen. Floor space allowance was held constant at 0–093 m² per bird and other related factors of management were standardised. The different sizes of flock had no significant effect on growth rate or mortality, but individual food consumption was significantly higher in the 400‐bird flocks than in the larger units.

At 18 weeks of age, some of the birds from each treatment were transferred to battery cages and others to deep‐litter laying quarters and records of their performance in terms of egg numbers and size, food consumption, mortality and body weight gain were taken over a period of 1 year. The only consistently significant finding was that birds reared in groups of 1200 tended to produce larger eggs (as shown by market grading) and, when housed on deep litter, to eat more food than birds reared in the smaller flocks.