鲁梅克斯K-1杂交酸模和干玉米秸混合青贮料喂牛试验

８头４～５岁的役用秦川母牛按配对原则分为对照组和试验组。两组牛的精料配方基本相同，但试验组牛饲粮用７．７５％的鲁梅克斯Ｋ－１杂交酸模粉（以下简称鲁梅克斯Ｋ－１）代替对照组中同等重量的小麦麸；对照组牛的粗料全部用干玉米秸，试验组半用６０％干玉米秸和４０％的玉米秸＋鲁梅克斯叶混合青贮料。正试期２０ｄ。结果表明：试验组牛的平均日增重为 ０．７８７ｋｇ，对照组０．６９０ｋｇ，试验组较对照组牛日增重提高了 １４．０６％；每增重 １ｋｇ活重试验组牛消耗精、粗料分别为２．５４ｋｇ、５．２５ｋｇ，对照组半分别为２．９０ｋｇ、５．５０ｋｇ，试验组较对照组个节约精料０．３６ｋｇ、粗料０．２５ｋｇ；试验组每头牛毛盈利为７３．３４元，对照组５９．４０元，前者比后者提高经济效益２３．４７％。说明在役用母牛饲粮中，用鲁梅克斯粉代替精料中的小麦麸并用玉米秸＋鲁梅克斯混合青贮料能获得良好的生产性能和经济效益。     

正反反复选择下近交对褐壳蛋鸡饲料利用率和繁殖性状的影响

本文估计了褐壳蛋鸡洛岛红(AA)和浅花苏赛克斯(BB)在正反反复选择(RRS)下的近交系数,分析了近交对选择标准饲料利用率及其相关性状和繁殖性状的影响。试验群体由两纯种及其正反交组合和相应的对照组组成。经过7个世代的RRS和近交试验,试验组AA和BB(括弧里为对照组1AA和1BB)用系谱材料计算出的平均累积近交系数分别为2.58％和3.23％(9.33和8.17%)或每代为0.43%(1.35%),用有效群体含量估计出的AA与BB的相应数值为2.91％与2.83％(5.84%与5.92％)或每代为0.42％(0.86％)。1％近交系数导致的孵化率和饲料利用率的近交衰退较严重(0.5％和0.4％),其次是产蛋性状(约0.3％),而体重和蛋重只有0.1％左右。在本研究中,通过连续7代的RRS与合适的留种率等措施,成功地将闭锁群体的近交系数控制在3%以下的低水平,消除或减轻了近交对饲料利用率等重要经济性状的不利影响。     

我国饲料工业发展概况

本文对我国饲料工业发展现状、存在问题、措施及对策三个方面进行了综述。     

补饲不同配方酶制剂对犊牛断奶后生产性能的影响

选择健康无病、6- 7月龄间断奶的公牛犊 30头 ,随机分成 3组 ,即对照组 CK、试验组 TE1和 TE2 ,每组 1 0头。对照 CK组饲喂基础日粮 ;试验 TE1和 TE2 组分别补饲0 .1 %由纤维素酶、果胶酶、蛋白酶与淀粉酶组成的酶制剂 E1和由木聚糖酶、果胶酶、蛋白酶与淀粉酶组成的酶制剂 E2 ;试验 60 d,测定加酶对生产性能的影响。结果表明 ,与 CK组相比 ,TE1组日增重提高 7.51 % (P<0 .0 5) ,混合精料、粗料与增重比各下降 7.0 0 % (P<0 .0 5)、1 .2 3% (P<0 .0 5) ;TE2 组增重提高 4.2 0 % (P<0 .0 5) ,混合精料、粗料与增重比各下降 3.86% (P<0 .0 5)和 0 .31 % (P>0 .0 5) ;试验组犊牛断奶后对粗饲料的适应性有所增强 ;两组酶配方中 ,以纤维素酶为主的 E1效果优于 E2     

The Effects of Feed Form on Consumption Time and Glucose and Insulin Response to a Concentrate Meal in Equine

This study tested the hypothesis that feeding an identically formulated, low sugar and starch concentrate in three forms (5-mm extruded [E], 4-mm pellet [P], and 19-mm oval [O]) would affect consumption rate and glucose or insulin responses, or both. Horses received 1.8 kg treatment feed in a randomized, crossover design, with samples taken every 30 minutes for 6 hours for blood glucose and insulin response. Pearson's correlation compared consumption time, insulin and glucose peak, and time to peak insulin and glucose. The pellet (P) elicited a lower (P = .01) glucose concentration at 2.5 hours than O. The pellet also elicited a lower (P = .03) insulin concentration at 5.5 hours than E and O. There were no differences (P > .05) in area under the curve (AUC) insulin, peak insulin, and time to peak insulin for the three treatments. Average insulin concentration was lower (P = .01) for P versus O. There were no differences (P > .05) in average insulin between P and E, nor between O and E. There were no differences (P > .05) in AUC and peak glucose concentration. Time to peak glucose was longer (P = .04) for P versus E. Average glucose concentration was lower (P = .02) for P versus O. Consumption time was longer (P = .03) for O versus P. There was a positive correlation between consumption time and time to peak insulin (r = 0.46, P = .029). Further research on feeding practices, feed forms, and consumption times that affect glycemic response is necessary.     

Effect of a short duration feed withdrawal followed by full feeding on marbling fat in beef carcasses

The effect of feed withdrawal for 48 h, prior to initiation of the finishing (fattening) period (75 d) on carcass marbling fat was studied in 120 European × British cross-bred heifers with an average weight of 585 ± 39 kg. Heifers were randomized in a 2 × 2 factorial design experiment with two dietary management treatments, where half the heifers were provided the feed components of steam rolled barley and barley silage either free choice or as a total mixed ration (TMR) containing 87% steam rolled barley and 13% barley silage with ad libitum vitamins and minerals via salt blocks for all animals. Within each dietary management treatment, 30 heifers were denied feed (water was available) for 48 h prior to the two week adaptation to the high grain diet preceding the 75 d finishing period. At the end of the 48 h feed denial blood samples were collected from the jugular vein prior to feeding for determination of glucose and insulin concentrations, which indicated that 48 h feed withdrawal consistently decreased (P = 0.0001) plasma concentrations of both glucose and insulin but the ratios of the concentrations of glucose to insulin were not affected. At slaughter samples of subcutaneous fat from the brisket (BF) and skirt muscle (pars costalis diaphragmatis; PCD) were procured for determination of chemical fat content, fat dissected from the muscle and for enumeration of adipocytes, less than 35 μm in diameter and to determine the average cell size in the dissected fat and from the BF by flow-cytometry of adipocytes fixed in osmium tetroxide. The carcass characteristics were also obtained. Although no differences due feed withdrawal for 48 h were evident for carcass weight, percent lean (saleable) meat yield, rib eye area, average fat cover, fat content of PCD or BF, the US marbling score was increased (P = 0.048) and the amount of dissected fat from the muscle tended to be higher (P = 0.107), thus 81% of the carcasses graded “US Choice” or “Canada AAA,” or displayed at least a “small” amount of intramuscular fat as compared (P = 0.0807) to 68% of the heifers not denied feed. Based on more than three years of weekly prices of carcasses that graded “Canada AAA” and “Canada AA,” these experimental results suggested that the expected price of a finished heifer could increase by $4.61 Canadian if a 48 h feed withdrawal was imposed prior to initiation of the finishing phase. Although significant differences in adipocyte numbers due to a single time 48 h feed withdrawal prior to initiation of the finishing phase were not detected, the carcass quality factors were affected leading to an odds ratio of 1.84 times in favour of cattle carcasses to grade “Canada AAA” than if fed continuously.     

Effects of feed intake on in situ rumen microbial contamination and degradation of feeds

An in situ study was conducted using four rumen cannulated wethers and five feeds (corn grain (CG), soybean meal (SBM), sunflower meal (SFM), vetch–oat hay (VH), and lentil straw (LS)) to determine (using ¹⁵N infusion techniques) the effects of two intake levels (40 and 80 g DM/kg W^0.75) on the microbial contamination and rumen degradation of DM or CP. Degradation studies were also performed for neutral and acid detergent fibres (NDF and ADF, respectively) of VH. In most cases, the evolution with time of the microbial DM adhered to particles fitted well to exponential curves, which diverged between both levels of intake due to the lower values attained at high intake. However, as a consequence of the large and progressive increase of the variability of microbial contamination, statistical evidence is only partial. This behaviour was less evident for CP contamination, especially in forages. The lack of these corrections underestimated (P < 0.001) the effective degradability (ED) of all tested fractions, with important differences between feeds. The intake level had not relevant effects on the distribution of soluble, insoluble available and unavailable fractions of DM or CP (or fibres in VH), but determined some changes in their degradation rates (k_d). Direct relations between these last values and rumen outflow rates (k_p) were shown in some feeds for the degradation of CP and also of DM in concentrates, whereas negative relations were shown for the degradation rates of DM in forages (or NDF and ADF of VH). All ED estimates decreased with the intake rise, but for CP this effect (P < 0.05) was only detected in SBM and VH. These decreases represent 40.8 (CG), 80.8 (SBM), 62.1 (SFM), 66.8 (VH), and 19.5% (LS) than those estimated considering only k_p changes, which shows the interest to consider conjointly the variations of both rates to study the effect of diet changes on ED.     

新型中草药添加剂在母猪阶段的喂养试验

分两组从母猪产前30 d至断乳进行试验观察。考虑到猪场喂药、产仔、拌料方便,试验组选择53头母猪在产前30 d给怀孕母猪饲喂添加新型中草药制剂(主要含多喂康颗粒Ⅰ型、益母草、鱼腥草);对照组选择42头母猪,根据该场日常饲养状况进行饲养(产前10 d投喂抗生素进行预防性用药)。通过新型中草药制剂喂养试验说明,新型中草药添加剂在产前30 d投喂对提高健仔数、成活率、出生重和断乳重有重要作用,使用新型中草药新制剂作为预防用药与抗生素相比成本降低了,生态效益也得到改善。     

不同季节收获的星星草对绵羊采食量和养分消化率的影响

旨在研究不同季节收获的星星草(Puccinellia tenuiflora)对绵羊采食量及养分消化率的影响。选用平均体重为30.37±2.15kg的乌珠穆沁公羊12只,随机分为4个处理,每个处理3个重复,分别饲喂四季收获的星星草。试验绵羊采取单笼饲养,预饲期15d,正式试验期7d,自由采食和饮水,采用全收粪法进行消化代谢试验。结果表明:绵羊四季采食星星草干物质含量分别为412.42、639.23、741.49和321.30g/d,秋季显著高于春季和冬季的干物质采食量(P<0.05);秋季星星草有机物消化率显著低于其他季节(P<0.05);不同季节的星星草对绵羊的碳、氮采食量均有显著影响(P<0.05),饲喂不同季节星星草的绵羊均处于氮的负平衡状态,分别为-1.12、-0.78、-0.13和-3.16。总之,星星草低的含氮量和采食量是限制星星草饲喂价值的重要因素。     

日粮中添加柠檬酸对雏鸡生长发育的影响

在雏鸡日粮中添加不同水平的柠檬酸，观察其对罗曼公雏生长发育的促进作用。结果表明，0．1％柠檬酸添加水平有提高生长速度和饲料转化率的作用。