加快黄牛改良推广南德温优良品种

南德温牛原产生英格兰的南德郡,经澳大利亚专家几十年的培育,形成了毛色红黄、体型硕大、体躯丰满、早熟、生长快、屠宰率高、净肉率达59．5％,是世界生产高档牛肉的三大品种之一。成年公牛平均体重可达1000～1200kg。成年母牛平均体重可达700～850kg,年产奶量1500～2000kg,高的达3300kg左右,乳脂率达4．2％,易受胎,护犊性能好。犊牛初生重达40～45kg,一般日增重可达1．3～1．5kg,最高的达2．3kg。本品种抗寒、耐热、适应性强,能适应中国南北各地气候。     

复合酶对生长猪效果试验

选择120头本地饲养的哈白猪随机分为4组,每组设2个重复。4组分别饲喂养0mg/kg、10mg/kg、100mg/kg、1000mg/kg的商品用复合酶制剂。试验结果表明,猪日粮中添加酶制剂,可促进生长和改善饲料利用率。与对照组相比,添加10mg/kg酶制剂组平均日增重提高7．69％（P＜0．05）,饲养利用率提高,4．70％（P＜0．05）,经济效益提高50．76（P＜0．01）;添加100mg/kg酶制剂组平均日增重提高7．69(P<0.05),饲养利用率提高8．39％（P＜0．01）,经济效益提高79．72％（P＜0．01）;添加1000mg/kg酶制剂组平均日增重提高3．08％（P＞0．05）,饲料利用率提高5．70％（P＜0．05）,经济效益提高－10．90％（P＞0．05）。     

尼温水牛泌乳性能研究

利用巴基斯坦尼里水牛作父本与温州水牛进行杂交试验。结果表明：尼温水牛的泌乳高峰期在前三个月，平均泌乳期317．2天，其中F1为317．5天，F2为314.5天，与温州水牛的泌乳期279．8天相比较延长了37．7天和34．7天，平均增加挤奶37．4天。尼温水牛的群体平均泌轧量为2231.8kg，日产奶量7.0kg，是温州水牛的2.2倍，其杂交一代优势值(H)为897．03，优势率(H％)为62．54％，具有较好的杂交优势，是一个相当理想的杂交组合，且杂交后的尼温水牛适应性好，牛乳营养丰富，具有显著的社会效益和经济效益，符合温州水牛乳肉兼用的育种方向。     

特种野猪引进及杂交选育试验效果的初报

引进特种野猪杂交商品肉猪一代8月龄体重比当地肉猪降低了24．21％,比特种野猪提高了61．01％,屠宰后的瘦肉率比当地肉猪提高55．09％;内脏油脂低2．79kg;失水率高3。1％;熟肉率低4．4％。加上外观肉色鲜红,野味浓郁、很受市场欢迎。经济效益良好。     

渤海黑牛肥育试验及屠宰测定

通过不同月龄组的对比肥育和屠宰测定结果,说明渤海黑牛公、阉牛的适宜肥育期为14—24月龄。在14—18月龄期间,在中等营养水平下,经120天短期肥育,渤海黑牛平均日增重迭1kg左右;每kg增重需TDN5.64kg,ME20.44Mcal、DCP747.60克,优亍其他各年龄组;屠宰率、净肉率、胴体产肉率分别达58.95％、51.12％、86.71％,与其它各月龄组差异不显著;眼肌面积、脂肉比、骨肉比、经济效益显著大于其他各年龄组。肉中蛋白质氨基酸含量达95.11％,其中必需氨基酸(不含色氯酸)40.85％,与秦川牛和日本和牛相近。从公、阉牛平均日增重、饲料报酬、屠宰率、净肉率、胴体产肉率、牛肉可食部分对比分析,公牛优于阉牛。同时可看出,渤海黑牛骨量较轻的特点。     

四川乳肉兼用牛群体的泌乳性能研究

以2213头成年乳肉兼用牛产奶量纪录和558个乳样的乳脂测定结果为基础材料,对四川乳肉兼用牛的泌乳性能进行了初步分析。结果表明,四川乳肉兼用牛的各胎次泌乳量为3889．4±1580．6 kg,泌乳期为283．5±35．2 d,乳脂率为4．509％±0．58％。其中第1胎至第5胎305 d平均泌乳量分别为3395．4±740．81 kg,4123．4±1038．8 kg,5260．7±1728．9 kg, 5149．6±1988．4 kg和4896．3±1979．5 kg;第1胎至第5胎平均乳脂率分别为4．403±0．32％,4．561±0．63％,4．561±0．72％,4．470±0．35％和4．497±0．73％,第5胎及5胎以上个体305 d平均产奶量为4602．3±1478．4 kg,表明四川乳肉兼用牛具有较好的泌乳性能。     

采用仔猪早期隔离断乳技术培养健康群的研究

采用“SEW技术实施方案”，对大约克、长大、金华猪共2240头进行早期隔离断乳试验。其结果，仔猪平均12日龄断乳，12～21日龄育成率98．57％，12～70日龄育成率95.41％；60日龄体重大约克25．61kg，长大25．76kg，金华猪16．28kg，平均比常规群提高48．43％（引入品种55．23％）；种猪特、一级率提高20个百分点，三级率下降35．2个百分点；蓝耳病、传染性胸膜肺炎等6种疾病阳性率降低30．5～68．4个百分点，其中传染性胸膜肺炎、伪狂犬病、传染性胃肠炎、圆环病毒阳性率均为0；社会经济效益显著。     

维多利亚紫花苜蓿在贵阳不同海拔地区的产量与营养成分含量研究

试验在贵阳市的4个不同海拔地区（950、1120、1210、1350m）设点,对维多利亚紫花苜蓿的生长、产量、营养成分进行了测定。结果表明：维多利亚紫花苜蓿秋季种植后141d可以第一次刈割,平均产量为1307．32kg。其生长速度与海拔高度呈负相关,海拔高度每升高100m,株高达到50cm的时间推迟5天,667m^2产量降低50kg。第一次刈割后66d株高达到50cm,平均产量为2304．5k。第二茬生长速度与海拔高度呈负相关,海拔高度每升高100m,株高达50cm的时间推迟4天,产量降低30kg左右。第三茬株高达到50cm的时间平均为74．5d,平均产量为2588．0kg,海拔高度每升高100m,植高达到50cm的时间推迟3天,产量变化不明显。在贵阳地区当年种植可以刈割3茬,利用时间282d,平均每茬产草量平均为2066．6kg／667m^2,年总产草量6199．8kg／667m^2;鲜草含水量平均为70．9％,干物质含量平均为29．1％,干物质中平均含CP26．3％、EE5．2％、CF25．9％、Ash9．6％、NFE33．0％、NDF36．1％、ADF32．6％、Ca1．7％、P0．8％、GE18．4MJ／k。     

荷兰牛产奶量又有提高

在荷兰的黑白花奶牛，产奶量再度增长。2004年9月至2005年9月，平均每头产奶349天，产奶9，257kg，含脂肪4．39％和蛋白质3．49％。前一年，平均每头产奶351天，产奶9，218kg。     

太阳能暖棚绵羊规范饲养试验及暖棚户饲养效果

1995年12月至1996年2月，对大通县青林乡和多林乡的177只绵羊进行了太阳能暖棚规范饲养试验和暖棚户饲养效果调查结果表明：在61天饲养期内试验群绵羊平均体重增加6．87kg，平均日增重112．6g，对照组绵羊平均体重下降3．78kg，平均日体重下降62．0g。暖棚饲养户羔羊繁活率和成畜减损率分别为78．99％和0．47％，敞棚户分别为64．56％和3．26％。暖棚饲养绵羊效果显著。     

青贮皇竹草饲喂奶牛效果分析

本试验选取体重、胎次、泌乳阶段、产奶量基本相近的健康中国荷斯坦产奶牛26头,配对分成两组,即对照组和试验组,进行青贮皇竹草替代青贮玉米秸的饲喂试验。对照组按原日粮不变,试验组用5 kg青贮皇竹草替代10 kg青贮玉米秸。预试期7 d,正试期21 d。结果表明:试验组与对照组相比,日均产奶量相对提高0.73 kg,差异显著(P<0.05);乳蛋白相对提高0.05个百分点,乳脂率相对提高0.03个百分点,总固体物相对提高0.06个百分点,差异均不显著(P>0.05);从经济效益比较,试验组每头牛日均收益相对提高2.21元。     

复合酵母培养物对奶牛生产性能的影响

通过在日粮中添加复合酵母培养物,研究其对荷斯坦牛生产性能的影响。结果表明,添加复合酵母培养物的试验组奶牛产奶量显著高于对照组(P<0.05),乳脂率也略有提高,但乳蛋白率和乳糖率与对照组相比差异不显著。     

苜蓿青干草替代部分精料对奶牛生产性能及经济效益的影响

本研究的目的在于探讨苜蓿青干草替代部分精料后对奶牛生产性能、牛奶品质和经济效益的影响,为在奶牛饲粮中合理利用苜蓿青干草和精料提供依据。选取体重、产奶量、胎次相近处于泌乳中期的中高产荷斯坦奶牛24头,随机分为4组。对照组日粮组成为全株玉米青贮料、花生秧和混合精料,精粗比为52∶48,试验A、B、C组分别用3 kg 苜蓿青干草替代1.5,2.0,3.0 kg精料,饲养期70 d。结果表明,试验A组、B组、C组产奶量极显著高于对照组(P<0.01),试验A组显著高于B组、C组(P<0.05),试验B组、C组差异不显著(P>0.05);试验A组、B组、C组的乳蛋白含量显著高于对照组(P<0.05),试验B组和C组显著高于A组(P<0.05);试验组的乳脂率极显著(P<0.01)和乳糖、干物质显著(P<0.05)高于对照组,各试验组之间差异不显著(P>0.05)。试验A组、B组干物质采食量显著高于对照组和C组(P<0.05),C组与对照组差异不显著(P>0.05),A组干物质采食量最高。试验组与对照组体细胞数差异不显著(P>0.05),但均较对照组低。试验B组、C组的粗蛋白表观消化率显著(P<0.05)和中性洗涤纤维表观消化率极显著(P<0.01)高于对照组,试验A组与对照组差异均不显著(P>0.05)。试验A组的纯增收益最高,为7.92元/d。由以上结果可知,用苜蓿青干草替代适量的精料补充料可以提高奶牛的生产性能,改善乳品质,增加收益,其中用3.0 kg苜蓿青干草替代1.5 kg精料组效果最好。     

Effect of restricted suckling on milk yield,composition and flow,udder health,and postpartum anoestrus in grazing Holstein cows

The effect of restricted suckling on milk yield and composition, udder health, and postpartum anoestrus in dairy cows in pasture-based systems, was studied in 32 Holstein multiparous cows and their calves. At calving, each cow–calf pair was randomly assigned to one of two treatments: restricted suckling (RS) of the cows by her own or another calf, twice daily for 30 min or artificial rearing (AR) of the calves with milk obtained from the bulk tank, offered twice a day in buckets. Treatments were applied until week 8 after calving. The diet of the cows consisted of direct grazing in improved pastures, corn silage and a commercial concentrate which was offered at milking. Milk production and composition, udder health, body condition score of the cows, body weight and milk intake of the calves were measured weekly, and the first postpartum ovulation was determined three times a week by ovarian ultrasonography. Cows with RS management had a lower machine-milked milk yield (17.9 vs. 24.8 kg/d), a lower fat percentage (3.21 vs. 4.11%) and 4% fat-corrected milk yield (16.2 vs. 25.7 kg/d), and also a lower average milk flow (1.35 vs. 1.76 kg/min) than cows in the AR treatment. There was no effect of treatment on milk protein percentage or udder health as measured by milk electrical conductivity. The interval from calving to first postpartum ovulation was shorter in the AR cows than in the RS cows (18.5 vs. 21.8 days). The RS calves consumed more milk (7.2 vs. 5.4 kg/d), gained more body weight (0.813 vs. 0.656 kg/d), and had a higher body weight at weaning (84.3 vs. 73.3 kg) than AR calves. Restricted suckling of grazing dairy cows had a negative effect on machine-milked milk yield, fat percentage and 4% fat-corrected milk yield, but had no effect on udder health or on improved weight gain and body weight at weaning of the calves.     

Economic consequences of postponed first insemination of cows in a dairy cattle herd

The purpose was to analyse the economic consequences of postponed first insemination of cows in dairy herds with different reproduction management, and to analyse the sensitivity of the results to a further decrease in beef prices, using a model simulating production and health in a dairy cattle herd. Three different period-to-first-insemination scenarios were analysed. Period to first insemination was defined as days post partum for initiating insemination at observed heat. The three scenarios consisted of a short period to first insemination (70 days for primiparous and 35 days for older cows), a 70 days postponed first insemination of primiparous cows and a scenario with 70 days postponed first insemination for all cows. At a 70 days postponed first insemination for primiparous cows a decrease in annual herd profit of 1% were found. A 70 days postponed first insemination for all cows led to a decrease in annual herd profit by 3% at good reproductive efficiency and 4% at poor reproductive efficiency. The herd profit was calculated as the profit to cover labour costs and fixed costs. Postponed inseminations might reduce labour per cow-year. The reduction in labour per cow-year need to be 3.2 h at good reproductive efficiency and 4.3 h at poor reproductive efficiency to counterbalance the reduction in herd profit by postponing first insemination for all cows by 70 days. In a situation with a 50% decrease in beef prices in a herd constrained by a milk quota (optimising profit per kg milk) herd profit was increased by 0.8% at good reproductive efficiency and 0.3% at poor reproductive efficiency by postponing first insemination for all cows by 70 days.     

饲粮中添加黄花蒿乙醇提取物对奶牛产奶性能及乳脂中共轭亚油酸含量的影响

本文旨在研究饲粮中添加黄花蒿乙醇提取物对奶牛产奶性能及乳脂中共轭亚油酸(CLA)含量的影响。试验选取体重(600±29)kg、胎次2~3胎、泌乳期(158±3)d及泌乳量(22.8±1.8)kg/d的泌乳期荷斯坦奶牛15头,采用完全随机区组设计分为3组,每组5头,进行为期40 d的饲养试验,其中1~9 d为预试期,10~40 d为正试期。对照组饲喂基础饲粮,试验1组和试验2组分别在基础饲粮中添加96和160 g/(d·头)的黄花蒿乙醇提取物。结果表明:整个试验期间,2个试验组的产奶量(第24、31和40天)、乳脂率、乳脂产量、乳蛋白率、乳蛋白产量、非脂固形物含量以及乳脂中的饱和脂肪酸、单不饱和脂肪酸、多不饱和脂肪酸、短链脂肪酸、中链脂肪酸和长链脂肪酸含量与对照组相比均无显著差异(P0.05);2个试验组的乳脂中CLA含量分别比对照组提高了30.7%和38.6%,其中试验2组与对照组差异显著(P0.05)。由此得出,饲粮中添加适量的黄花蒿乙醇提取物对奶牛产奶性能没有明显影响,但可以提高其乳脂中CLA含量,从而优化乳脂中脂肪酸的比例。     

Mesquite pod meal as an additive increases milk total solids,lactose, fat and protein content in dairy cows

The objective was to evaluate the intake, digestibility, milk yield and composition of cows fed mesquite pod meal (MPM). Five crossbred dairy cows, with an average body weight of 450?±?5 kg and producing 10?±?1 kg of milk/day were distributed in a 5?×?5 Latin square arrangement with five periods of 20 days each, comprised of 15 days for adaptation to the experimental diets (T1?=?0%, T2?=?1.5%, T3?=?3.0%, T4?=?4.5% and T5?=?6.0% MPM) and 5 days for data collection. Variables were assessed by analysis of variance and regression at P?<?0.01 and P?<?0.05 of significance, using the Student’s test. Animals were kept on pastures and the concentrates were provided at 6 kg/animal divided in two meals per day. The inclusion of 3.0% mesquite pod meal did not affect the intake, digestibility of nutrients and milk yield, but it changed milk composition. The dietary inclusion of 3.0% mesquite pod meal as a palatability enhancer increases the percentage of milk solids, lactose, fat and protein. Therefore, mesquite pod meal can be included in diets for dairy cows to improve the nutritive value of milk.

     

The association between first DHI milk-test parameters and subsequent displaced abomasum diagnosis in dairy cows

First Dairy Herd Improvement Corporation (DHI) test milk that was sampled prior to displaced abomasum (DA) diagnosis was used to examine the association between milk yield (kg), fat (%), protein (%), or fat/protein ratio and DA in dairy cows. 27 DA cases were matched to 3 controls per case by herd and calving date. Logistic regression was used to examine the effect of each milk parameter on the odds of DA, adjusting for lactation number and days in milk (DIM) at test. Higher odds of DA diagnosis was found with lower milk yield, higher milk fat percentage, lower milk protein percentage and higher fat/protein ratio. We conclude that milk yield, fat percentage, protein percentage and fat/protein ratio may be used to detect cows at risk for DA. Our findings also indicate that cows diagnosed with DA were energy deficient prior to DA diagnosis.     

西门塔尔母牛在贵州舍饲条件下的适应性观察

对西门塔尔母牛进行了为期四年的饲养观察,对其生长情况和繁殖性能进行测定统计,结果表明:在圈养舍饲条件下,初生重平均为40.42kg,2岁平均日增重为0.64kg,2胎后平均体重为640.26kg,生长发育良好;平均繁殖成活率为69.17%,平均泌乳量为3285.99kg,患蹄病较多,圈养舍饲条件对其繁殖泌乳性能产生影响。     

Digestion in steers and lactational performance of Jersey cows fed diets varying in natural protein level continuously or on alternate days

Five crossbred beef steers (515 kg) were used in a Latin square experiment and 36 lactating Jersey cows (12 primiparous, 310 kg; 24 multiparous, 365 kg) were used in a completely randomized design study to determine effects on characteristics of digestion and lactational performance of daily alternation of the dietary level of natural protein (NP). In Experiment 1, steers were fed diets of 50% bermudagrass hay and 50% concentrate. Concentrate was approximately 18% crude protein (CP), formulated to be 60, 80 or 100% NP (varying proportions of soybean meal, urea and ground corn), and was fed at 1.5% body weight (dry matter basis). These concentrates were fed daily or ones with 60 and 100% NP were fed on alternate days. Alternate day feeding did not markedly affect characteristics of digestion, including ruminal escape of feed protein, and NP level of concentrate fed continuously had no effects either. In Experiment 2, cows were subjected to treatments similar to those in Experiment 1, and performance on d 20-40 of lactation was measured. Concentrate was given at 1 kg (as fed)/2.15 kg milk produced, yielding a dietary concentrate level of approximately 40% (dry matter basis). Alternate feeding depressed (P less than 0.05) overall milk fat percentage. Alternate feeding increased production of milk and protein and body weight of primiparous cows but caused little change with multiparous cows. Besides increasing the dietary level of concentrate, perhaps alternate feeding regimes have utility to lower milk fat level without impairing milk production. Level of NP in concentrate fed continuously did not affect performance by multiparous cows though primiparous cow performance was generally enhanced, possibly because CP intake was adequate for multiparous cows but marginal for primiparous cows. However, overall, efficiency of production of solids-corrected milk rose slightly with increasing NP.