青山羊后备公羊蛋白质需要的研究

本研究的目的在于探讨后备公羊的蛋白质需要,为此设计了饲养试验、消化代谢试验、比较屠宰试验、内源尿素及代谢粪氮的测定、后备公羊繁殖性能测定等方法。试验结果表明,后备公羊饲喂CP 为12.14%的日粮为宜;用低氮日粮测得青山羊后备公羊的 EUN 为0.104g/kg·W~(0.75)·d,MFN 为0.150g/kg·W~(0.75)·d,对蛋白质的最小维持需要为1.30gDCP/kg·W~(0.75)·d,维持需要为3.66gCP/kg·W~(0.75)·d;用析因法得出后备公羊蛋白质需要的公式为 RCP(g/d)=3.6W~(0.75)+0.56ΔW(g)青山羊是我国著名的羔皮品种,具有性成熟早、繁殖率高、适应性强、遗传力稳定等特点,用其生产的猾子皮在国际上享有较高声誉。为使青山羊的优良种质特点得以充分发挥并节约饲料成本,1980年以来山东农业大学动物营养研究室对青山羊营养需要进行了系列研究,本研究为其中的一个分支。国内外对后备公羊的营养需要尤其是蛋白质需要的研究很少,而适宜的蛋白水平对后备公羊的生长发育及繁殖性能具有重要意义。本研究通过饲养试验,消化代谢试验、内源尿氮及代谢粪氮的测定、比较屠宰试验、精液品质检查、性行为测定等方法,研究不同蛋白水平对后备公羊生长及繁殖性能的影响.制订其蛋白质需要量,为合理饲养后备公羊提供科学依据。     

肉用兔生长阶段蛋白质需要量的研究

24只45±3日龄的塞北兔仔兔随机分为三组,采用饲养试验,氮平衡试验,屠宰试验及低氮日粮试验等方法研究肉兔生长阶段蛋白质的需要量。结果表明:(1)生长内兔的 EUN 为144mgN/W~(0.75)d,MFN 为182mgN/W~(0.75)d;(2)生长肉兔对蛋白质的消化率受日粮总蛋白的影响(P<0.01),随着日粮中精料蛋白所占比例的提高,日粮蛋白质的消化率提高(P<0.01);(3)肉用兔对蛋白质的代谢率受其采食量及试兔体重的双重影响(P<0.01),随着蛋白质采食量及体重的增大显著地下降。综合所有试验结果,析因法得出肉用兔代谢体重及平均日增重(ADG)与消化蛋白质采食量(DCPI)的关系式:DCPI(g/d)=2.60W~(0.75)+0.3587ADG(g)     

日粮中不同代谢能、降解蛋白和非降解蛋白水平对泌乳前期细毛羊生产性能的影响

用87只2～3岁的河北细毛羊进行了粗蛋白水平为10.6％～22.2％;代谢能为11.05～11.98MJ/kg;降解蛋白(RDP/CP)为77.1％～87.6％和不同非降解蛋白(UDP)为44.91～57.94g/日/只等4个水平对泌乳前期母羊体重、泌乳力及羔羊生长发育影响的研究,同时探讨了羔羊日吮乳量与羔羊平均日增重的关系。试验结果表明,河北细毛羊泌乳前期(1～50天)ME、RDP和UDP的适宜供给量分别为1.02MJ/kgW~(0.75)/d、9.20g/kgW~(0.75)/d和3.08g/kgW~(0.75)/d。羔羊平均日吮乳量(X)与日增重(Y)的关系为Y=0.0072+0.2536X(r=0.5201,P<0.01)。在低营养水平饲养条件下,适当给母羊增加降解氮食入量,可提高增重和泌乳量。     

不同养分进食水平及日粮降解蛋白质与代谢能比对妊娠后期细毛羊生产性能的影响

用87只2～3岁的河北细毛羊母羊,对日粮不同代谢能(ME)、降解蛋白(RDP)和非降解蛋白(UDP)水平对妊娠后期母羊体重及羔羊初生重影响进行了研究。试验结果表明,河北细毛羊妊娠后期(100～150天)能量和蛋白质的适宜供给量分别是0.79MJME/kgW~(0.75)/d、7.02gRDP/kgW~(0.75)/d和2.32gUDP/kgW~(0.75)/d。这一营养水平可保证母羊体重适度增加。同时还发现母羊日粮能量及蛋白质水平对羔羊初生重无显著影响。     

樱桃谷肉鸭对能量和蛋白质需要的研究

本研究采用饲养试验、代谢试验和比较屠宰试验测定樱桃谷内鸭对能量和粗蛋白质的需要量。结果表明,樱桃谷肉鸭的平均维持代谢能(MEm)和维持粗蛋白(CPm)的需要量是:1～21日龄MEm=925.8 KJ/W~(0.75)/d,CPm=10.2g/W~(0.75)/d:21～49日龄MEm=884.5 KJ/W~(0.75)/d,CPm=8.2g/W~(0.75)/d。平均每克增重所需代谢能和粗蛋白质:1～21日龄分别为10.1 KJ,0.2 g:22～49日龄分别为23.9KJ,0.3g。故樱桃谷肉鸭每日代谢能总需要量(Y_(ME))和粗蛋白质总需要量(Ycp)可按下列公式推导:对于1～21日龄:Y_(ME)=925.8W~(0.75)+10.1△W(KJ/d);Ycp=10.2W~(0.75)+0.20△W(g/d);对于22～49日龄:Y_(ME)=884.5W~(0.75)+23.9△W(KJ/d);Ycp(?) .2W~(0.75)+0.29△W(g/d)。式中,W~(0.75)为肉鸭代谢体重(单位kg),△W为日增重/单位g)。试验结果显示,日粮的能量和粗蛋白质水平对肉鸭的能量和蛋白质需要量有一定影响。     

青山羊种公羊能量需要量的研究

12只18月龄青山羊种公羊随机分为2组,通过饲养试验、气体代谢试验及屠宰试验,研究种公羊能量代谢规律及需要量。试验表明(1)青山革种公羊的MEm为507W~(0.75)KJ,代谢能的增重效率K_G为0.157;(2)绝食产热为282.4KJ/kgW~(0.75),非配种期一天产热量(HP)与食入代谢能(MEI)呈强直线相关(P<0.01):HP/W~(0.75)=186.2+0.45MEI/W~(0.75);(3)本试验中,高能量水平对精清生化指标、性行为及精液品质各项指标影响差异不显著。综合试验结果,按析因法得出青山羊种公羊非配种期与配种期代谢能需要量分别为:ME_R=507W~(0.75)+36⊿W,ME_R=(507+122n)W~(0.75)。     

青山羊泌乳期哺育双羔母羊的蛋白质营养需要及其代谢规律的研究

选用体重、产羔期基本相同的青山羊泌乳母羊24只 ,随机取6只用于内源N测定试验和第一次比较屠宰试验 ,其余18只随机分成三组 ,每组6只 ,分别喂以蛋白质水平不同(1组 -100 %、2组 -120 %、3组 -80%) ,但能量水平相同的日粮。整个试验分泌乳前期(1～30天)和泌乳后期(31～70天) ,进行饲养试验、消化代谢试验、内源N测定试验和比较屠宰试验。饲养试验表明 :试羊的平均日蛋白质采食量(CPI)与乳中蛋白量呈强相关(P<0.01) ,其回归关系为 :泌乳前期 :Y=2.81X +33.21 ;泌乳后期 :Y=4.24X +21.67;式中Y为CPI ;X为乳中蛋白量。消化代谢试验表明 :试羊对干物质消化率、日粮粗蛋白质消化率、粗蛋白质代谢率及可消化粗蛋白质代谢率分别为69.71%、68.16 %、23.00 %、33.11%。内源N测定试验表明 :试羊泌乳前期和后期的内源尿氮(EUN)均为0.127g/kg W0.75 d ;代谢粪氮(MFN)泌乳前期为0.378g/kgW0.75 d ,泌乳后期为0.328g/kgW0.75 d。比较屠宰试验表明 :试羊的体蛋白及其他组分含量差异不显著(P>0.05)。根据上述试验结果可得出青山羊泌乳期哺育双羔母羊的可消化粗蛋白质需要量公式为 :Y=2.79W0.75+90.82L;式中 :Y为RDCP(g/d);L为产奶量(kg/d);W0.75为代谢体重(kg)。     

特种野猪基础氮代谢及维持蛋白质需要研究

为了测定特种野猪的基础氮代谢和内源氨基酸排出规律,得到维持粗蛋白质需要计算公式。试验选择体重接近45 kg的特种野猪6头,置于代谢笼中,单笼饲养,采用无氮饲粮法测定其代谢粪氮(MFN)、内源尿氮(EUN)、体表氮损失(SLN)及内源氨基酸损失规律。结果表明:特种野猪1 kg干物质采食量(DMI)的MFN损失为1.243 g,内源氨基酸排出量为6.076 g;每单位代谢体重的EUN损失为0.21 g/d,SLN为0.024 g/d。特种野猪的维持粗蛋白质需要量计算公式为:R=6.25×[(1.243×DMI)+(0.21×BW~(0.75))+(0.024×BW~(0.75))]/(BV×TD)。式中:R为维持粗蛋白质需要(g/d),DMI为每天DMI(kg/d),BW为动物的体重(kg)。BV为蛋白质生物学价值,取值0.55;TD为蛋白质真实消化率,取值0.80。     

小尾寒羊泌乳期蛋白质需要量及其代谢规律的研究

选用6只小尾寒羊泌乳母羊，通过饲养试验、消化代谢试验、比较屠宰试验等手段，研究其蛋白质需要量。结果表明，小尾寒羊泌乳母羊代谢粪氮（MFN）和内源尿氮（EUN）的排出量分别为0．1312和0．13459／kg·W0.75·d。小尾寒羊泌乳期维持可消化粗蛋白需要量为1．51W0.75g／d，每产1kg奶需可消化粗蛋白829。小尾寒羊泌乳母羊的可消化粗蛋色总需要量（RDCP，g／d），可按下式求得：RDCP＝1．51W0.75＋82MP式中：W0.75——代谢体重，kg；MP——为产奶量，kg。     

牦牛妊娠后期能量和蛋白质维持需要量的研究

本试验旨在研究牦牛妊娠后期能量和蛋白质的维持需要量,为牦牛饲养标准的建立提供基础参数。利用随机分组设计将15头体重相近、经同期发情处理并本交配种的妊娠牦牛随机分为3组(每组5头牛),分别按自由采食(AL组)、80%采食量(IR80组)和60%采食量(IR60组)3个饲养水平进行饲喂。每组各选3头牦牛在妊娠180～185 d和210～215 d时进行2期消化代谢试验,在妊娠186～190 d和216～220 d时进行2期气体代谢试验,测定其碳代谢指标(食入碳、粪碳、尿碳、甲烷碳、二氧化碳碳)、能量代谢指标(食入总能、粪能、尿能、甲烷能)和氮代谢指标[食入氮(NI)、粪氮、尿氮],计算得出沉积氮(NR)、代谢能采食量(MEI)和能量沉积量(ER),通过回归分析得出牦牛妊娠后期维持净蛋白质和维持代谢能需要量。结果显示:牦牛妊娠180和210 d时NI[g/(kg W~(0.75)·d)]与NR[g/(kg W~(0.75)·d)]的回归方程分别为NR=1.046_((±0.18))NI-0.600_((±0.09))和NR=1.065_((±0.15))NI-0.611_((±0.07)),其纵坐标截距即为维持净氮需要量,乘以系数6.25即为维持净蛋白质需要量;牦牛妊娠180和210 d时MEI[kJ/(kg W~(0.75)·d)]与ER[kJ/(kg W~(0.75)·d)]的回归方程分别为ER=1.722_((±0.55))MEI-755.760_((±184.19))和ER=0.988_((±0.25))MEI-534.870_((±87.35)),当ER=0时的MEI即为其维持代谢能需要量。由回归方程得出,牦牛妊娠180和210 d时维持净蛋白质需要量分别为3.75和3.82 g/(kg W~(0.75)·d),维持代谢能需要量分别为438.81和541.64 kJ/(kg W~(0.75)·d)。     

波尔山羊×隆林杂交羔羊育肥期能量和蛋白质营养需要的研究

试验旨在研究育肥期波本杂肉羊能量和蛋白质营养需要量参数,筛选出一个最佳能量和蛋白质搭配的饲料配方,为科学饲养提供理论依据和生产指导。试验选择16只3月龄断奶波隆杂交F1代公羔,采用4×4拉丁方设计,以NRC（1981）营养需要推荐量为参考设计了低能低氮、高能低氮、低能高氮和高能高氮（NRC）4种能氮比日粮,分别为日粮1、2、3和日粮4。试验结果表明,舍饲波隆杂交羔羊育肥期对象草 玉米型日粮干物质采食量与代谢体重和日增重的关系为：DMI（g/d）=181.3W0.75－0.61ΔW－886.2（r=0.9287）;舍饲波隆杂羔羊育肥期粗蛋白质（CP）、总能（GE）、消化能（DE）需要量的估测模型分别为：CP（g/d）=19.56 W0.75＋0.25ΔW－128.6（r=0.7836）,GE（MJ/d）=2.98 W0.75＋0.023ΔW－18.69（r=0.8257）,DE（MJ/d）=1.26 W0.75－.006ΔW－3.56（r=0.6236）;3~6月龄舍饲育肥期波隆杂羔羊,日粮总能代谢率平均为0.49%,粗蛋白质的消化率平均为0.63%,每增重1 g体沉积蛋白质需要量为0.32 g。     

Energy requirements of young female cattle. 6. Energy requirements

Results taken from 6 experiments with young female cattle comprising 477 metabolism periods served the derivation of the animals energy requirement in the development range greater than 125 kg live weight according to the factorial method. The energy requirement per kg LW0.75 and day, calculated from metabolism data, was independent of the stage of development and the intensity of feeding. It averaged 455 +/- 66 kJ metabolizable energy/kg LW0.75.d and 250 +/- 37 kJ NEFcattle/kg LW0.75.d respectively. The partial energy requirement for live weight gain, expressed in net energy fat, was equivalent to the energy content of the live weight gain. Energy retention and thus energy requirement per kg live weight gain increased with the live weight and reached a maximum of 26 MJ. Energy retention per kg live weight gain largely depended on the intensity of feeding and the stage of gravidity. Restrictive energy supply and progressing gravidity decreased energy content in the weight gain. The influences mentioned were taken into consideration on the derivation of the partial requirement for live weight gain. Equations were developed for the estimation of the energy requirement of young female cattle, which can be applied to both gravid and non-gravid cattle.     

Influence of Carnichrome on the energy balance of gestating sows

Twelve multiparous sows with an average initial weight of 182 kg were used in a randomized complete block design to determine the effects of feeding Carnichrome (50 mg of carnitine and 200 microg of chromium picolinate per kilogram of feed, as fed) on energy and nitrogen utilization in early, mid-, and late gestation. All sows were fed a diet with or without Carnichrome for the preceding 28-d lactation, the weaning-to-estrus period, and for the duration of gestation. Daily feeding allowances over pregnancy were based on calculated energy and nutrient requirements to achieve a target sow maternal weight gain of 20 kg and remained constant throughout gestation. Heat production (HP) and its partitioning (activity, thermic effect of feeding short term [TEFst], basal) were determined in early (wk 5 or 6), mid- (wk 9 or 10), and late (wk 14 or 15) pregnancy using indirect calorimetry. Net maternal weight gain and total number of fetuses averaged 21.6 kg and 16.4, respectively. Organic matter and energy digestibility for the Carnichrome diet was greater (P < 0.05), which resulted in greater DE and ME contents (0.6%, P < 0.05) compared with the control diet. The digestibility coefficient of energy in the current experiment for a typical corn and soybean meal diet (92%) was greater than that predicted from DE values of corn and soybean meal in feeding tables (88%). Carnichrome had no effect on total HP, energy retained as protein or lipid, and maternal energy retention in early, mid-, or late gestation. Heat production in late gestation increased linearly (4.0 kJ/[kg BW0.75 x d]) for each additional day from d 90 to 110, despite the reduction of ME intake per unit of BW0.75. Metabolizable energy requirement for maintenance was 405 kJ/(kg BW0.75 x d). On average, activity HP was 116 kJ/(kg BW0.75 x d), which was equivalent to 20% of ME intake; however, this value ranged from 11 to 37% between sows, which corresponds to duration of standing ranging from 210 to 490 min/d. Energy cost of standing activity averaged 0.30 kJ/(kg BW0.75 x min). In conclusion, Carnichrome had no effect on the components of heat production and maternal weight gain during gestation, although it improved energy and organic matter digestibility of the diet.     

7～10月龄杂交肉牛蛋白质需要量及其代谢规律的研究

选择18头健康、体重(183.58±7.89)kg的6月龄利木赞×鲁西黄牛杂交生长牛,采用饲养试验、消化代谢试验和尼龙袋试验,研究了7~10月龄生长牛的蛋白质需要量及其代谢规律。试验结果表明,本试验日粮的粗蛋白质对7~10月龄生长牛的消化率、沉积率和瘤胃降解率分别为75.93%、35.28%和56.28%。生长牛在7~10月龄时的维持粗蛋白质需要量为6.46 g/kgW0.75.d,增重的粗蛋白质需要量为463.42 g/kg。生长牛在7~10月龄时期,其粗蛋白质需要量(RCP,g/d)、可消化粗蛋白质需要量(RDCP,g/d)和瘤胃降解蛋白质需要量(RDP,g/d)可按下式计算:RCP=6.46W0.75+463.42△W;RDCP=4.91W0.75+351.87△W;RDP=2.76W0.75+198.04△W。     

Effect of energy and lysine intake in gestation on sow performance

Nutrient intake during gestation has an impact on gestation parameters and subsequent lactation performance. The objectives of this experiment were to determine the impact of feeding two levels of amino acids in gestation on sow BW changes in gestation and lactation, and litter size, and to evaluate a factorial method for determining daily energy requirements. At mating, 419 sows (Camborough 15; Pig Improvement Canada, Acme, AB) were assigned randomly within Parities 1, 2 or 3+ to a gestation diet containing either 0.44% (low lysine) or 0.55% (high lysine) total lysine and 3,100 kcal DE/kg; other indispensable amino acids were adjusted to lysine based on ideal protein ratios. Feed allowance in gestation was determined factorially using estimated DE requirements for maintenance, maternal gain, and conceptus growth. Sows were allowed free access to the lactation diet. Gestation BW gain from d 0 to 110 was affected by parity (61.2, 60.0, and 42.3 kg for Parity 1, 2, and 3+, respectively; P < 0.05) but not (P > 0.10) by gestation lysine level. Sow BW changes from d 0 of lactation to weaning were affected by parity (0.5, 6.8, and 5.8 kg for Parity 1, 2, and 3+, respectively; P < 0.01) and gestation BW gain (P < 0.01), but not by gestation lysine level (5.0 vs 3.8 kg for low and high lysine, respectively; P > 0.10). Total piglets born was affected by parity (11.5, 12.1, and 12.5, for Parity 1, 2, and 3+, respectively; P < 0.01) and increased with increasing sow BW gain (P < 0.05). Total piglets born alive (mean = 11.2) was increased with increasing sow BW gain (P < 0.05). Total litter weight born alive was affected by parity (15.9, 18.6, and 19.4 kg for Parities 1, 2, and 3+, respectively; P < 0.01) and gestation BW gain (P < 0.05). The model used to determine daily energy intake requirements resulted in an average BW gain of 10.6 kg above the targets set by the model. Total lysine intakes greater than 10.6 g/d in gestation did not improve sow productivity. Setting target weight gains in gestation and feeding to meet these targets may not always provide predictable results due to a number of factors that affect the energy requirement in the sow.     

生长犊牛蛋白质需要量及其代谢规律规定

选择10月龄鲁西黄牛×利木赞杂交公牛15头，采用饲养试验和消化代谢试验，研究生长犊牛的蛋白质需要量及其代谢规律。试验结果表明，生长犊牛对日粮蛋白质的消化率为61.37%，沉积率为27.62%。生长肉牛代谢粪氮(MFN)和内源尿氮(EUN)的排出量分别为0.40g／kgw     

Changes in weight and composition in various tissues of pregnant gilts and their nutritional implications

The objectives of this study were to characterize the quantitative changes in various body tissues of high-lean type gilts during gestation and to determine the protein needs of pregnant gilts based on changes in tissue contents. Thirty-five gilts (158.2 +/- 8.3 kg) were housed in individual gestation crates with six unbred gilts randomly selected and slaughtered to provide data for d 0 of gestation. The remaining gilts were bred and assigned randomly to one of six slaughter groups: d 45, 60, 75, 90, 102, and 112. Gilts were fed 2 kg (as-fed basis) of gestation diet daily (3.1 Mcal/kg of ME and 0.56% lysine). Carcass soft tissue, bone, gastrointestinal tract, spleen, pancreas, kidney, liver, uterus, fetus, mammary gland, and the remaining viscera were separated and weighed. Carcass soft tissue, liver, remaining viscera, uterus, and gastrointestinal tract were ground, freeze-dried, and analyzed for composition. Body weights of the gilts increased quadratically (P < 0.001) during gestation. Weights of carcass soft tissue and uterus, including placenta, increased linearly (P < 0.001) during gestation. Weights of individual fetuses, fetal litters, individual mammary glands, and the entire mammary glands increased cubically (P < 0.001) during gestation. Crude protein in carcass soft tissue increased cubically (P < 0.01), whereas DM and ether extract (EE) in carcass soft tissue increased linearly (P < 0.01). The DM, CP, and EE in the entire mammary glands increased quadratically (P < 0.001) during gestation. The DM, CP, and EE in fetal litter increased cubically (P < 0.01) as gestation progressed. The accretion rates of the conceptus, fetal litter, individual fetus, individual mammary gland, and CP in fetal litter differed (P < 0.05) before and after d 70 of gestation. The CP daily gain from all maternal and fetal tissues was 40 and 103 g/d before and after d 70 of gestation, respectively, suggesting that pregnant gilts may require different quantities of dietary protein during gestation. Based on the maintenance requirement, maternal tissue gain, and conceptus gain, pregnant gilts require 6.8 and 15.3 g/d of true ileal-digestible lysine (or 147 and 330 g/d of true ileal-digestible protein) before and after d 70 of gestation, respectively, to support their true biological needs.     

大尾寒羊泌乳期蛋白质需要量及其代谢规律的研究

选用６只大尾寒羊泌乳母羊,通过饲养试验、消化代谢试验、比较屠宰试验等手段,研究其蛋白质需要量。结果表明,大尾寒羊泌乳期代谢粪氮（ＭＦＮ）和内源尿氮（ＥＵＮ）的排出量分别为０．１２２９和０．１３８０ｇ／ｋｇＷ０·７５．ｄ。大尾寒羊泌乳期维持可消化粗蛋白需要量为１,７６ｇ／ｋｇＷ０·７５．ｄ,每产１ｋｇ奶需要消化粗蛋白７０ｇ,大尾寒羊泌乳期可消化粗蛋白的总需要量（ＲＤＣＰ,ｇ／ｄ可按下式求得：ＲＤＣＰ＝１．７６Ｗ０·７５＋７０ＭＰ（式中：Ｗ０·７５为代谢体重,ｋｇ：ＭＰ为产奶量,ｋｇ。     

Energy requirement for the maintenance and utilization of energy convertible to protein and fat deposits in piglets

In respiration experiments with 16 piglets the effect of feeding level on energy metabolism was studied with the aim of estimating energy requirement and costs of protein and fat deposition. Four groups of 4 animals each were fed on different levels of digestible protein and metabolisable energy (ME). Group 1 was fed intensively, whereas the piglets of group 2, 3 and 4 received 92, 76 and 55% respectively of the amounts given to group 1. In the group 1-4 mean daily weight gain was 457, 437, 360 and 205 g respectively. As a consequence the rearing period increased from 44 days to 46, 56 and 98 days. The variation in feed intake affected not only significant differences in energy deposition but also changes in gain composition. In the groups 1-4 the average energy deposition was 4.2 MJ, 4.0 MJ, 3.0 MJ and 1.4 MJ per day and protein gain exceeded fat gain in all groups. Estimations of energy requirement for maintenance were carried out by means of multiple regression analysis using different models. As a result a value of 428 MJ ME per kg live weight 0.75 was obtained and the models used have hardly shown any influence. It seems that higher values for maintenance requirement, as formerly published, are due to different conditions of livestock management, such as temperature. For all groups the average efficiency of ME-utilisation for growth was 0.77, ranging from 0.73 to 0.82. The variation can be attributed to the changes in protein and fat formation. The groups with a higher proportion of protein in the accretion utilised metabolisable energy more efficiently than the intensively fed group 1 with the highest proportion of fat, the difference between the groups being in the range from 0.73 to 0.82. The efficiency of ME-utilisation for protein deposition was calculated to be 0.83 and for fat deposition 0.73. As a higher coefficient for fat formation may be expected in the light of the high fat content in the ration, calculations with an assumed coefficient from 0.75 and 0.80 had been carried out, showing that the efficiency of ME-utilisation for protein gain would only decrease to 0.79 and 0.73 respectively. According to these results the statement must be called in question, that the energetic efficiency of protein deposition of about 50 to 55% - as measured in numerous experiments mainly with older pigs - can generally be accepted.     

Modelling energy utilisation in broiler breeder hens

1. The objective of this study was to determine a metabolisable energy (ME) requirement model for broiler breeder hens. The influence of temperature on ME requirements for maintenance was determined in experiments conducted in three environmental rooms with temperatures kept constant at 13, 21 and 30 degrees C using a comparative slaughter technique. The energy requirements for weight gain were determined based upon body energy content and efficiency of energy utilisation for weight gain. The energy requirements for egg production were determined on the basis of egg energy content and efficiency of energy deposition in the eggs. 2. The following model was developed using these results: ME = kgW0.75(806.53-26.45T + 0.50T2) + 31.90G + 10.04EM, where kgW0.75 is body weight (kg) raised to the power 0.75, T is temperature ( degrees C), G is weight gain (g) and EM is egg mass (g). 3. A feeding trial was conducted using 400 Hubbard Hi-Yield broiler breeder hens and 40 Peterson males from 31 to 46 weeks of age in order to compare use of the model with a recommended feeding programme for this strain of bird. The application of the model in breeder hens provided good productive and reproductive performance and better results in feed and energy conversion than in hens fed according to strain recommendation. In conclusion, the model evaluated predicted an ME intake which matched breeder hens' requirements.