全混合日粮对羔羊瘤胃代谢产物浓度变化的影响

选用４只４月龄装置永久性瘤胃瘘管的羔羊,按４×４拉丁方试验设计,研究了４种不同处理的全混合日粮（ＴＭＲ）对羔羊瘤胃消化代谢的影响。试验期采集瘤胃液,研究其ｐＨ值、氨氮、尿素氮、总氮及蛋白质浓度的动态变化规律。试验结果表明,在含玉米秸的ＴＭＲ中,以尿素蛋白精料等氮代替豆饼,对试羊瘤胃液ｐＨ值及蛋白质含量均无明显影响（Ｐ＞０．０５）,虽显著提高了试羊瘤胃液氨氮浓度（Ｐ＜０．０１）,但仍未超出瘤胃微生物利用氨的限量范围;在含尿素蛋白精料的ＴＭＲ中,玉米秸的碱化处理,可明显提高试羊瘤胃液ｐＨ值（Ｐ＜０．０５）,而其氨氮浓度及蛋白质含量均无显著变化（Ｐ＞０．０５）;对含尿素蛋白精料及碱化玉米秸的ＴＭＲ进行颗粒化加工,并未明显影响试羊瘤胃液ｐＨ值、氨氮及蛋白质浓度（Ｐ＞０．０５）;各处理组试羊瘤胃液ｐＨ值及氨氮浓度均处于正常生理范围内。从而证明在全混合日粮中以尿素蛋白精料取代豆饼、玉米秸的碱化处理及ＴＭＲ的颗粒化加工均具有理论可行性。     

用尿素饲喂育成绵羊对比试验

本试验利用尿素代替１２．５％的植物蛋白质饲料饲喂育成棉羊表明：试验组羊比对照组羊降低饲料费用１８．１３％，在喂量相同的情况下，每千克混合料的增重多５７．５克（日增重多２３克），提高１４．５６％（Ｐ＜０．０１），经济效益提高１．３６倍。     

不同加工处理的幼羊全混合日粮各养分表观消化率的研究

选用４只４月龄幼羊，按４×４拉西方试验设计，用常规全收粪法测定了４种不同处理幼羊全混合日粮（ＴＭＲ）干物质（ＤＭ）、有机物（ＯＭ），粗蛋白（ＣＰ），中性洗涤纤维（ＮＤＦ），酸性洗涤纤维（ＡＤＦ）及总能（ＧＥ）的表观消化率。试验结果有机物在含玉米秸的ＴＭＲ中，以尿素精料等氮代替豆饼对日粮ＤＭ，ＯＭ，ＣＰ，ＮＤＦ，ＡＤＦ及ＧＥ的消化率均无显著不利影响；     

秸秆生物处理技术研究（四）：——生物处理玉米秸对肥育羊生长性能 …

选择１６只６月龄细毛羊,研究生物处理玉米秸对育成羊肥育性能的影响。结果表明：生物处理玉米秸可增加羊对玉米秸的采食量（Ｐ〈０．０５）,同时提高羊的增重（Ｐ〈０．０１）;生物处理玉米秸作为羊的粗饲料,其经济效益优于碱化玉米秸和中等质量羊草。     

黑麦日粮中添加不同酶制剂对肉仔鸡生产性能及肠道食糜粘度的影响

本文用１８０只肉仔鸡,进行饲养试验,研究黑麦日粮添加４种不同酶制剂,ＮＱ、ＲＭ１、ＲＭ２和ＲＭ３,对肉仔鸡的生产性能以及肠道食糜及泄殖腔粪样粘度的影响。酶制剂ＮＱ和ＲＭ１含有高的木聚糖酶活（７７００ＩＵ／ｇ,３４５０ＩＵ／ｇ）能极显著改进（Ｐ＜０．０１）增重（８．４％,１６．０％）和饲料转化率（１５．４％,１４．４％）,ＲＭ２,含有相对低的木聚糖酶（６０ＩＵ／ｇ）和相对高的阿拉伯呋喃糖苷酶活（５．３ＩＵ／ｇ）,产生类似的效果（Ｐ＜０．０１）：增重提高１０．５％,饲料转化率提高１１．８％,然而ＲＭ３,由于含木聚糖酶活较低（５ＩＵ／ｇ）和较高的蛋白酶活（８０ＩＵ／ｇ）,则对增重无效,但亦可改善饲料转化率（６．４％,Ｐ＜０．０５）。上述酶制剂在降低肠道食糜和泄殖腔粪样粘度方面与增重和饲料转化率有相同的趋势。一般说来,日粮中添加的酶量与食糜相应的粘度成倒数关系。这些结果证明：具有较高木聚糖酶活的酶制剂能明显降低肠道食糜和泄殖腔粪样的粘度,从而改善饲喂黑麦日粮肉仔鸡的生产性能。     

膨化鸡粪饲料饲喂生长肉猪试验

采用西宁市华青蛋禽公司生产的膨化鸡粪饲料饲喂生长肉猪，试验１、２、３组分别按基础饲粮的１０％、２０％和３０％添加，代替基础饲粮。经６０天试验，试验１、２、３组的平均日增重分别比只喂基础饲粮的对照组提高２３．３２％（Ｐ＜０．０１），１２．３５％（Ｐ＜０．０５）和降低６．２３％（Ｐ＞０．０５）；每千克增重分别比对照组节省混合料０．３２ｋｇ、０．２３ｋｇ和０．２８ｋｇ；每千克增重所需的饲料成本分别比对照组节支０．１３元和多支出０．１４元、０．３４元。试验证明，膨化鸡粪饲料以添加１０％为宜，可获得较好的经济效益。     

高温条件下复合抗应激剂对肉鸡的影响

本文研究了高温条件下复合抗应激剂对肉鸡的影响。结果表明：经历３２ ℃一周的５ ～８ 周龄肉鸡采食量、增重、饲料转化率均显著下降（Ｐ＜ ０ ．０１） ，饮服复合抗应激剂显著改善增重和饲料转化率（Ｐ＜ ０ ．０１） ， 采食量未见明显改变，饲料转化率达到常温水平。３２ ℃１６ 小时血浆皮质酮、Ｔ３ 显著下降（Ｐ＜ ０ ．０１） 、Ｔ４ 显著升高（Ｐ＜ ０ ．０１） ；３２ ℃１２０ 小时血浆皮质酮、Ｔ３ 升高并超出常温组（Ｐ＜ ０ ．０５） 、Ｔ４ 较１６ 小时下降但仍高出常温组（Ｐ＜ ０ ．０５） 。饮服复合抗应激剂时血浆皮质酮、Ｔ３ 、Ｔ４ 显现相同变化规律，但这种变化得到显著缓解     

低蛋白质氨基酸平衡饲粮对早期断奶仔猪腹泻和生产性能的影响

本研究选用１８头２８±１日龄断奶的杂交仔猪（平均体重约５．５ｋｇ），研究低蛋白质氨基酸平衡饲粮对早期断奶仔猪腹泻和生产性能的影响。试验结果显示：（１）低蛋白质氨基酸平衡饲粮使仔猪血浆挥发性盐基氨含量、血浆尿素氨含量和腹泻指数降低（Ｐ＜０．０５或０．０１）。（２）采食全植物蛋白型氨基酸平衡饲粮（ＣＰ１８．３％）的仔猪，其平均日增重（ＡＤＧ）、平均日采食量（ＡＤＦＩ）和料肉比（Ｐ／Ｇ）与采食复合蛋白型对照饲粮（ＣＰ１９．７％）的仔猪差异不显著（Ｐ＞０．０５），但前者的增重成本比后者降低（Ｐ＜０．０５）３１％。（３）采食复合蛋白型氨基酸平衡饲粮（ＣＰ１８．４％）的仔猪的生产性能优于采食复合蛋白型对照饲粮（ＣＰ１９．７％）的仔猪，前者的ＡＤＧ和ＡＤＦＩ分别提高（Ｐ＜０．０５）６１％和３２％，Ｆ／Ｇ和增重成本分别下降（Ｐ＜０．０５）２４％和３７％。（４）采食全植物蛋白型氨基酸平衡饲粮的仔猪，其ＡＤＧ和ＡＤＦＩ低于（Ｐ＜０．０１）采食复合蛋白型氨基酸平衡饲粮的仔猪。前者的Ｆ／Ｇ和增重成本趋于高于后者，但差异不显著（Ｐ＞０．０５）。以上结果表明，低蛋白质氨基酸平衡饲粮可显著降低仔猪断奶后腹泻和提高仔猪生产性能。复合蛋白型?     

肉鸡饮服“必补-18”的抗应激效果研究(Ⅱ)

本文研究了“必补＿１８”对应激条件下肉鸡的影响。结果表明：“必补＿１８”显著改善了０～３周龄肉鸡的增重、饲料转化率，显著提高了血清γ＿球蛋白水平和成活率，采食量未见有显著改变。５～８周龄肉鸡经历高温３２℃一周，其增重、饲料转化率和采食量均显著下降（Ｐ＜０．０１），饮服“必补＿１８”显著提高了增重和饲料转化率（Ｐ＜０．０１），采食量未见有差异，高温一周过程中，３２℃１６小时血浆皮质酮，Ｔ３先显著下降（Ｐ＜０．０１）、Ｔ４显著升高（Ｐ＜０．０１），３２℃１２０小时时，血浆皮质酮、Ｔ３回升且显著高于常温组（Ｐ＜０．０５），Ｔ４较１６小时显著下降（Ｐ＜０．０１）但仍高于常温组（Ｐ＜０．０５）。在高温条件下饮服“必补＿１８”血浆皮质酮、Ｔ３和Ｔ４呈现与高温对照组同样规律的变化，但这种变化得到显著缓解（Ｐ＜０．０５）     

高温季节蛋鸡日粮养分适宜浓度的研究

在高温季节（２５．５～３９．４℃），配制５种日粮，分别将其喂蛋鸡。第一种日粮（对照组）按现行饲养标准配制。对第２～５种，不同程度地调整其中代谢能、粗蛋白及必需氨基酸等主要养分的浓度。饲养结果表明：与对照组比较，采食第４种日粮的蛋鸡产蛋率提高１５．２０％（Ｐ＜０．０１），饲料用于产蛋的效率提高１５．７％（Ｐ＜０．０１），产蛋饲料成本降低８．９％（Ｐ＜０．０５）；采食第５种口粮的蛋鸡产蛋率提高１０．５５％（Ｐ＜０．０５），饲料用于产蛋的效率提高９．９９％（Ｐ＜０．０５），但产蛋饲料成本增加１１．６７％（Ｐ＜０．０５）；采食第２种日粮的蛋鸡产蛋率和饲料效率降低，饲料成本提高，但均不显著（Ｐ＞０．０５）；采食第３种日粮的蛋鸡产蛋率、饲料效率和产蛋饲料成本均与对照组相似。     

Growth performance and carcass characteristics of growing ram lambs fed sweet sorghum bagasse-based complete rations varying in roughage-to-concentrate ratios

Different roughage-to-concentrate ratios of sweet sorghum bagasse (SSB) (a by-product of the biofuel industry)-based complete diets were assessed. Twenty four growing Nellore × Deccani ram lambs aged about 3 months (average body wt., 10.62?±?0.25 kg) were randomly allotted to four complete rations (CR) varying in roughage-to-concentrate ratios viz. 60:40 (CR-I), 50:50 (CR-II), 40:60 (CR-III) and 30:70(CR-IV) for a period of 180 days. The feed intake was comparable among the lambs fed different experimental complete diets. Average daily weight gain (in grams) was 77.31?±?4.90, 81.76?±?5.16, 85.83?±?2.83 and 86.30?±?3.25, and feed conversion ratio (in kilograms of feed per kilogram gain) averaged 11.42?±?0.68, 10.57?±?0.64, 10.17?±?0.37 and 9.96?±?0.38 in ram lambs fed CR-I, CR-II, CR-III and CR-IV rations, respectively. Statistically, differences in daily weight gain and feed conversion ratio among the lambs fed four experimental rations were not significant (P?>?0.05). The cost per kilogram gain was significantly (P?<?0.01) higher in ram lambs fed CR-IV and CR-III rations compared to CR-I ration, and it was comparable between CR-I and CR-II rations. Dressing percentage averaged 44.90?±?0.15, 42.57?±?0.72, 43.67?±?0.16 and 44.42?±?0.76 for the respective diets. No significant difference and trend was observed in preslaughter weight, empty body weight, carcass weights, dressing percentage, wholesale cuts and edible and non-edible portions of experimental animals. Similarly, no significant variation could be seen in bone and meat yield (in per cent) and their ratios in various wholesale cuts among the dietary treatments. The roughage-to-concentrate ratio did not affect the chemical composition of meat; however, the fat content of meat was linearly increased with increase in the proportion of concentrate in the diets. The results of the experiment indicated that SSB can be included at 60 % level in the complete diet for economical mutton production from growing Nellore × Deccani ram lambs.     

小麦替代玉米对肉仔鸡生产性能、免疫器官、血液指标和全肠食糜黏度的影响

试验以玉米基础日粮为对照组,设小麦基础日粮、小麦基础日粮加木聚糖酶、黑曲霉发酵小麦为试验组,选择1日龄AA肉鸡360羽,随机分成4组,每组3个重复,每个重复30羽,公母混雏,预试期1周,第2周转入正试期,第4周末屠宰,测定生产性能、免疫器官指数、血液指标、全肠食糜黏度,对盲肠内容物进行菌落分离,并对肝脏和脾脏做组织切片,进一步分析免疫功能。结果表明,①生产性能：7～14日龄,发酵小麦组平均日增重极显著低于其他3组（P<0.01）,料重比最高,与其他3组相比差异极显著（P<0.01）,小麦组和小麦加酶组的料重比差异不显著（P>0.05）,但二者均高于玉米组,差异极显著（P<0.01）。15～22日龄,发酵小麦组平均日增重极显著低于其他3组（P<0.01）;玉米组和小麦加酶组平均采食量无显著性差异（P>0.05）,但二者均高于发酵小麦组,低于小麦组,差异极显著（P<0.01）;玉米组和小麦加酶组的料重比差异不显著（P>0.05）,小麦组和发酵小麦组的料重比差异也不显著（P>0.05）,但前两组极显著低于后两组（P<0.01）。23～30日龄,发酵小麦组平均日增重低于其他3组（P<0.01）;玉米组和小麦加酶组平均采食量无显著性差异（P>0.05）,但二者均高于发酵小麦组,低于小麦组,差异极显著（P<0.01）;发酵小麦组料重比高于玉米组和小麦加酶组,低于小麦组,差异极显著（P<0.01）。②发酵小麦组脾脏指数与小麦加酶组差异显著（P<0.05）,胸腺指数与小麦组差异极显著（P<0.01）,玉米组和小麦加酶组差异不显著;③盲肠内容物菌落分离结果显示,对28日龄肉仔鸡盲肠厌氧菌总数、乳酸菌数的影响差异不显著（P>0.05）,小麦加酶组大肠杆菌数与玉米组相比差异显著（P<0.05）,但小麦加酶组和玉米组的大肠杆菌数与发酵小麦组和小麦组相比差异不显著（P>0.05）;④血液指标：4个组T3、T4、血糖、尿酸水平差异极显著（P<0.01）⑤不同日粮肉仔鸡肝和脾组织切片图显示,小麦日粮组肝脏组织、淋巴细胞局灶性增生面积大,其他组间无明显差异;小麦日粮组脾脏出现红髓淤血,其他组无明显变化。     

可溶性干酒糟（DDS）在育肥猪日粮中的应用研究

研究了可溶性干酒糟（DDS）作为饲料原料对生长育肥猪生长性能的影响。选用72头健康体重约70 kg的三元育肥猪,随机分成2个处理组,每个处理组2个重复,每个重复18头猪,对照组饲喂基础日粮,试验组饲喂含40%DDS的试验日粮,试验正式期20 d。结果显示,与对照组相比,试验组育肥猪的平均日增重、平均采食量和料肉比方面无明显差异（P>0.05）,从经济效益分析来看,与对照组相比,试验组猪在日采食成本和日增重成本方面分别下降了1.41元/kg和1.50元/kg,整个育肥周期每头猪可多获利约75元。试验证实在生长育肥猪的日粮中添加DDS能够完全满足育肥猪的生长需要,并可降低养殖成本,进一步提高经济效益。     

Effect of altering nutrient density (concentrate to roughage ratio) and restricting energy intake on rate, efficiency and composition of growing lambs

Two hundred ninety-eight Rambouillet ewe and wether lambs approximately 9 mo old from Texas were allotted to pens (29 to 30 lambs/pen). Two replicate pens were fed each of five diets. Two methods of restricting energy intake were evaluated: altering nutrient density (55% vs 72.5% vs 90% concentrate levels) and restricting intake of the 90% concentrate pelleted diet (92.5% or 85% ad libitum intake). Daily gains were highest with the 72.5% concentrate level and feed efficiency was poorest with the 55% concentrate diet fed ad libitum. Altering nutrient density did not reduce energy intake because lambs compensated by increasing feed intake at the lower nutrient densities. Actual feed intake was 89.5% of ad libitum for the 92.5% of ad libitum intake level and 84% of ad libitum at the 85% of ad libitum intake level due to refusal to consume some fines from the 90% concentrate diet. Feed refusal was greatest for lambs with ad libitum access to feed. Average daily gain was depressed by 8% at the 85% intake level. However, feed efficiency was improved (P less than .01) by 20% when intake was restricted to 92.5% of the ad libitum intake level. Differences in carcass traits were small, but consistent; carcass fat content was reduced slightly by restricting feed intake at constant slaughter weight.     

不同植酸酶对雏期乌骨鸡生长性能的影响

选用80只4日龄雏期乌骨鸡,随机分成4组(1个对照组和3个处理组),每组20只试鸡。以玉米、豆粕为基础日粮,通过降低饲料中有效磷水平,添加不同水平植酸酶的方法进行饲喂试验,确定植酸酶在雏期乌骨鸡饲料中的应用是否可行。结果表明,处理组与对照组在日增重上无明显差异(P>0.05),处理组Ⅰ和处理组Ⅲ试验鸡日增重较对照组分别提高了11.69%和4.05%。另外,处理组Ⅰ日增重比处理组Ⅱ、处理组Ⅲ分别提高了13.91%、7.33%,且处理组Ⅰ显著高于处理组Ⅱ(P<0.05)。此外,处理组试验鸡的日采食量极显著高于对照组(P<0.01),处理组Ⅰ、Ⅱ、Ⅲ较对照组分别提高了16.84%、37.28%和41.22%,但随着植酸酶添加水平的增加各处理间日采食量处理组Ⅲ>处理组Ⅱ>处理组Ⅰ,达到了极显著水平(P<0.01)。而在料肉比方面,对照组与处理组Ⅰ极显著低于处理组Ⅱ和Ⅲ(P<0.01),但处理组Ⅱ与处理组Ⅲ之间差异不显著(P>0.05)。     

葡萄渣对羔羊生产性能、屠宰性能和养分消化代谢的影响

本试验采用单因子完全随机试验设计,选择60只3月龄左右杜寒F₁代公羔进行试验,测定不同水平葡萄渣对羔羊生产性能、屠宰性能和养分消化代谢的影响。本试验设4个饲粮处理组,每个处理15个重复,每个重复一只羊,Ⅰ为基础饲粮,Ⅱ、Ⅲ和Ⅳ处理组为饲粮中分别含有8%,16%和24%的葡萄渣,缩合单宁(condensed tannins,CT)含量分别为0,1.5,3.0和4.5 g/kg。结果表明,Ⅱ、Ⅲ、Ⅳ组羔羊日采食量、日增重、胴体重、屠宰率和胴体脂肪含量都显著高于Ⅰ组(P＜0.05),N表观存留率极显著高于Ⅰ组(P＜0.01),但Ⅰ组羔羊的酸性洗涤纤维和N表观消化率显著高于Ⅳ组(P＜0.05);Ⅱ组羔羊的饲料转化率显著高于Ⅰ组(P＜0.05),净肉率极显著高于Ⅰ组(P＜0.01)。随着CT含量的增加,羔羊的N、中性洗涤纤维和酸性洗涤纤维表观消化率逐渐降低,N的表观存留率逐渐升高,综合考虑羔羊日增重、饲料转化率、屠宰性能和养分利用率等指标,饲粮中葡萄渣以8%~16%为宜。     

小黑麦干草对羔羊生产性能及采食行为的影响

为探究小黑麦(×Triticale Wittmack)干草对舍饲羔羊生产性能和采食行为的影响,本研究选用18只舍饲湖羊公羔,随机分为对照组、试验Ⅰ组和Ⅱ组,每组6只;对照组饲喂基础日粮,试验Ⅰ组和Ⅱ组在基础日粮中分别用10%、20%的小黑麦干草等量替代粗料。结果表明:Ⅰ组试验羊的平均日增重为189.72 g,显著高于对照组和Ⅱ组(P<0.05);试验羊采食量随小黑麦干草添加比例的增加而降低,Ⅱ组采食量显著低于Ⅰ组和对照组(P<0.05),采食时长极显著高于Ⅰ组和对照组(P<0.01);Ⅰ组试验羊排泄次数显著高于对照组(P<0.05),与Ⅱ组无显著差异(P>0.05);Ⅰ组试验羊反刍周期、反刍时间、反刍食团数和食团咀嚼总次数都极显著高于Ⅱ组(P<0.01)。综上可知,小黑麦干草作为粗饲料在羔羊日粮中适宜添加比例为10%,这为小黑麦干草饲料化开发利用提供了理论基础。     

瘦肉型猪规模化养殖生长肥育期基础饲粮配方筛选试验

试验共使用８４头杜长大试猪,研究按理想可消化氨基酸模式利用不同蛋白源配制的基础饲粮对生长肥育猪生产性能的影响。试验结果：豆粕＋鱼粉、豆粕、豆粕＋棉粕＋菜粕３种不同蛋白源构成的基础饲粮,无论生长期、肥育期还是生长肥育全期日增重差异均不显著,采食量和饲料／增重比也很接近,肥育猪的瘦肉率和背膘厚等指标无大的差异。但豆粕＋棉粕＋菜粕日粮较豆粕＋鱼粉日粮千克增重饲料成本低４．６３％。表明,按理想可消化氨基酸     

Feeding forage mixtures of alfalfa hay and maize stover optimizes growth performance and carcass characteristics of lambs

A feeding experiment was carried out to determine the effects of different proportions of alfalfa hay and maize stover on the growth performance and carcass characteristics of fattening lambs. Forty‐two healthy 3.5‐month‐old male Small‐tail Han lambs of 23.89 ± 0.38 kg body mass were assigned to seven groups, which were fed mixed diets composed of maize stover and alfalfa hay containing 0%, 30%, 40%, 50%, 60%, 70% or 100% maize stover on a dry matter (DM) basis. Each lamb received 1.5 kg DM of forage mixture three times daily and supplementary concentrate (0.5 kg corn per lamb per day) for 60 days. Compared with the control forage diet of maize stover only, forage intake rate and forage conversion rate on the 40% maize stover/60% alfalfa hay mixture were 30% and 5% higher, respectively. Body weight, dressing percentage and net income were 6.7 kg, 8% and 94.37 Yuan higher per lamb, respectively. Thus, feeding lambs with a forage mixture of maize stover and alfalfa hay in a ratio of 40:60 optimized the production performance, slaughter performance, and the income derived from lambs.     

Effect of sex and feeding system on feed intake, growth, and meat and carcass characteristics of fattening Assaf lambs

The effect of feeding system and sex on intake, growth and carcass and meat characteristics of Assaf fattening lambs was studied. Twenty four weaned Assaf lambs, half males and half females were used. After an adaptation period, lambs were randomly assigned to one of the two feeding systems studied. Control lambs received ad libitum commercial concentrate (70% barley, 22% soybean meal, 4.8% wheat, 0.5% bicarbonate, 2.7% mineral–vitamin premix) and barley straw. Free Choice lambs had ad libitum and separate access to whole barley grain and a protein supplement (73.3% soyabean meal, 16% wheat, 1.7% bicarbonate, 9% mineral–vitamin premix). Lambs were slaughtered at 25 kg LBW. Feed intake was not significantly affected by sex (P > 0.05) but Free Choice lambs showed higher dry mater intake than the Control lambs. Nevertheless, only males from the Free Choice group showed an improvement in feed efficiency rate (P < 0.05) and average daily gain (P < 0.01) relating to the Control lambs. Neither feeding system nor feeding system × sex interaction significantly affected non-carcass weight, fat depots, cold carcass weight, dressing percentage, main proportions of commercial cuts and meat characteristics (P < 0.05). As it was expected, female lambs showed a lower average daily gain and a higher feed conversion efficiency than male lambs (P < 0.001) which was related to a greater fat deposition. Meat characteristics were unaffected by sex, with the exception of longissimus lumborum fat content, which was higher in female lambs.The present results suggest that Free Choice feeding system might be suitable for intensively reared male lambs since improvements in daily weight gain and feed conversion rate were achieved, with no adverse effect on carcass and meat quality. Despite the selected diet of both, males and females, did not differ in the crude protein content, the use of Free Choice feeding system for female lambs did not improve performance compared to the Control group.