冬小麦杂种后代灌浆速度的研究

为了研究冬小麦杂种后代灌浆速度遗传规律,我们从三个角度,十五种双亲灌速组合类型,分析了灌浆速度的遗传特点和遗传参数、不同双亲灌速组合类型对后代灌速的影响及其亲子关系密切程度;同时还对灌速进行了通径分析.结果表明,灌速为数量性状、不完全显性,呈现细胞核遗传和明显的“倾快”现象.后代灌速受双亲灌速共同作用,其中快亲起主导作用,慢亲也有一定的制约作用.双亲差异愈小,亲子关系愈密切;其中双亲灌速平均值与后代的关系皆比母与子、父与子密切:而父与子较母与子关系密切.灌速遗传力较高,在早代进行个体定向选择,可望获得较好的选择效果.欲提高灌速,要注重千粒重、功能叶面积、株粒重的选择,同时兼顾灌浆时间、株穗数、株粒数的选择,使其协调发展,综合提高.综合分析,以双亲灌速快,且灌速差异中等偏小,快速亲本作父本的组配形式为最好.     

高产奶牛挤奶量挤奶时间相关数学模型的建立

在采用挤奶机进行挤奶的挤奶厅里,利用人均挤奶头数来评估挤奶厅设备设施运行效能的方法已愈来愈被人们所接受。在进行挤奶厅工艺设计和挤奶设备选型时必须以奶牛的班次挤奶量及其挤奶时间作为基本设计依据。然而,奶牛的上述参数,随个体差异很大。本文在收集了大量实时观测的数据基础上,用曲线回归分析法处理了试验数据建立了以荷茨坦奶牛为主要品种的高产奶牛班次挤奶量及其相应的挤奶时间相互关系间的数学模型,为进行挤奶厅的工艺设计提供了基本计算公式。     

奶山羊单剂量肌肉和静脉注射丁胺卡那霉素后乳药浓度测定

本文报道了常规单剂量肌注和静注国产丁胺卡那霉素后乳药浓度变化,探讨了全身给药对乳房局部感染的治疗效果。对16只泌乳萨能奶山羊常规单剂量(D=7mg/kg)肌注丁胺卡那霉素的研究表明:给药后12小时有9只测到乳药浓度(0.18～0.65μg/ml),24小时仅一只测到乳药浓度,36小时所有羊乳药残留皆低于检测限(0.1μg/ml;对其中10只羊同剂量静注给药后12小时,仅一只未测到乳药浓度,24小时仅一只测到乳药浓度,36小时乳药残留皆低于检测限。 以上乳药浓度测定表明:常规剂量以每日一次或两次全身给药对敏感菌所致乳房炎治疗效果不确实(乳药浓度达不到最低抑菌浓度);根据乳药残留量提出休药期为24小时。     

Effect of milking frequency in early lactation on energy metabolism, milk production and reproductive performance of dairy cows

The objective of this study was to evaluate the effect of imposing different milking frequencies for the first 4 weeks of lactation on energy balance, blood metabolic profiles and reproductive performance. The milking frequencies imposed were once daily for the first 4 weeks of lactation and twice daily subsequently (X1), twice daily for the entire lactation (X2) and three times daily for the first 4 weeks of lactation and twice daily subsequently (X3). Two weeks prior to the first expected calving date, sixty-three multiparous, Holstein-Friesian cows, were allocated to treatments based on expected calving date, parity (lactation number = 2 and lactation number > 2), BCS and BW. Mean DMI was lower (P < 0.05) on X1 than X2 (15.7 and 17.1 kg/day) over the first 4 weeks of lactation, but DMI on X3 was not different to either. Milk yield was lower (P < 0.05) on X1 than on X2 and X3 (24.1, 31.9 and 31.4 kg/day) from weeks 1 to 4 and at week 10 of lactation (30.9, 33.9 and 33.7 kg/day) but was not different at week 20. Yield of milk constituents followed the same pattern as milk yield. Milking frequency had no significant effect on milk fat or protein concentration but milk lactose concentration was higher (P < 0.05) on X1 than on X2. Cows on X1 experienced less (P < 0.05) negative energy balance than those on X2 and X3 from weeks 1 to 4, with no difference between X2 and X3. Cows on X1 lost less BW (P < 0.05) from weeks 1 to 4 and lost less BCS up to day 73 of lactation than cows on X2 and X3. Plasma NEFA and BHB concentrations tended to be lower and plasma glucose tended to be higher on X1 than on X2 and X3 from weeks 1 to 4, while plasma insulin was higher on X1 than on X2 and X3 for the first 2 weeks of lactation. There was no difference between treatments in any reproductive performance variable measured. These results indicate that reduced milking frequency decreases milk yield and improves energy balance and metabolic status in early lactation.     

Concentrate composition for Automatic Milking Systems — Effect on milking frequency

The purpose of this study was to investigate the potential of affecting milking frequency in an Automatic Milking System (AMS) by changing ingredient composition of the concentrate fed in the AMS. In six experiments, six experimental concentrates were tested against a Standard concentrate all supplied in the amounts of 5 kg/cow/day. Fifteen cows were fed the experimental concentrate and another 15 cows the Standard concentrate for 14 days and then for the next 14 days the cows were fed the opposite diets to be their own control. The change from one mixture to the next was done over only one day. In each experiment the 30 cows were composed of 12–14 of Danish Holstein, 8–10 of Danish Red and 8 were Jerseys. Basal mixed ration (MR) was fed ad libitum and intake was recorded individually. The effect of the different concentrates on intake and production was evaluated within experiment against the Standard concentrate. A marked effect was found on the number of visits of the cows in the AMS and the subsequent milk production in relation to composition of the concentrate. The composition of the concentrates also influenced the composition of the milk and the MR intake. Based on the overall responses the cows preferred a mixture containing Barley and Oats. Also Wheat based concentrate appeared to be preferred to concentrate based on Maize or Barley and the cows did not like the Fat rich or the pure Artificially dried grass concentrate used in the experiment.     

摩拉、尼里及其中国水牛杂交后代的若干泌乳生理特性的观察

选用泌乳摩拉水牛19头、尼里14头和三品杂11头,测定排乳反射潜伏期,各乳叶的乳池乳、反射乳和残留乳,并采乳样测定干物质含量,乳脂率和乳脂球直径。观测排乳速率的动态变化。 结果表明:排乳反射潜伏期以摩拉较长,且易出现排乳抑制,尼里居次,三品杂较短。乳池乳依次为5.24±3.92,3.13±2.83,2.58±1.07％;反射乳为82.29±20.66,86.83±31.55,91.08±18.19％;残留乳为12.17±5.17,5.79±2.25,10.60±6.43％。三部分乳的干物质含量、乳脂率和乳脂球直径一般以残留乳最高,乳池乳较低。左右两侧乳叶泌乳量相似。排乳持续时间4—12分钟,排乳高峰多在第2—4分钟,往往有排乳间断现象。     

澳荷斯坦牛引入河南省后的产奶性能分析

澳荷斯坦牛引进河南后,由于饲养方式的转变,其产奶能力有了较大提高。将228头试验牛分为高、中、低产3组,分别测定并比较其产奶性能的差异。结果表明:一胎305 d平均产奶量接近6 500 kg;牛群第1、第2胎各泌乳月平均日产奶量均以第2个泌乳月为最高;高产奶牛在泌乳期第1个月就表现出高产状态。高产牛群305 d产奶量与90 d产奶量、最高日产奶量、最高月产奶量都呈强正相关关系;中产牛群305 d产奶量与90 d产奶量、最高日产奶量、最高月产奶量呈低度相关;低产牛群305 d产奶量与90 d产奶量和最高月产奶量间存在强正相关关系,最高日产奶量与305 d产奶量间为低度相关。     

产犊季节、胎次及牛场对荷斯坦牛泌乳性能的影响

本研究收集了3个千头以上奶牛场共8872条相关信息,采用多因素方差分析法分析了不同产犊季节、胎次和牛场对泌乳天数、305d校正奶量、305d脂肪产量、305d蛋白产量和全泌乳期产奶量5个泌乳性能指标的影响。结果表明,不同产犊季节、胎次和牛场都极显著影响奶牛的该5项泌乳性能（P〈0．01）。夏季和秋季产犊奶牛的泌乳性能较为理想。夏季产犊奶牛的泌乳天数和全泌乳期产奶量最高,其他三个泌乳性能指标都位居第二;秋季产犊奶牛的305d校正奶量、脂肪产量和蛋白产量都显著高于其他三个季节（P〈0．05）,泌乳天数和全泌乳期产奶量也仅次于夏季。头胎牛的各项泌乳性能都显著高于其他胎次的奶牛（P〈0．05）,其次为2胎产犊奶牛。随着胎次的增加,泌乳性能的各项指标都有不同程度的降低。不同的牛场极显著地影响奶牛的泌乳性能（P〈0．01）。     

计量瓶式挤奶机牛奶记录管理系统的开发与应用

近年来,一些规模化牛场配置了水平较高的自动识别、自动计量的转台式或鱼骨式挤奶机,但因配置全进口自动化的挤奶机投资过大,目前半自动化的计量瓶式挤奶机仍然是我国奶牛场挤奶机配置的主流。针对计量瓶式挤奶机的计量需手工记录和人工制表汇总核算的情况,河南中荷奶业科技发展有限公司联合有关单位利用单片机开发了现场输入设备和管理系统。本文对该系统的功能、基本结构和应用情况作了较为详尽的介绍。     

Effect of cattle management practices on raw milk quality on farms operating in a two-stage dairy chain

In many developing countries, milk production varies greatly according to farm size, cattle breed, and milking practices. However, production systems often are dominated by smallholder farms. Therefore, relatively small volumes of milk are delivered daily from numerous farms to intermediate cooperatives which supply industrial units. This paper argues that in such two-stage dairy chains, milk quality could be improved by focusing on farming practices rather than on the testing of individual deliveries. Indeed, it is difficult to analyze their quality due to technical, economic, and logistic limitations. The objective of this study is to link on-farm practices with milk chemical quality parameters (fat and protein) and hygienic quality criteria (Aerobic Plate Count, APC and Coliforms). Cattle management practices were monitored monthly over one year on 23 farms located on an irrigation scheme in Morocco. 276 milk samples were analyzed. The monthly variability of milk quality parameters was then characterized. Results show that average cow milk chemical parameters vary within a normal range. They remain primarily linked to the genetic type of cows, the lactation stage, and the conversion of feed concentrates’ net energy into milk. Overall milk hygienic quality was poor (APC and Coliforms counts were 100 fold international norms), due essentially to a lack of hygiene and inadequate milking conditions (hands, udder, and teat washing, type of bucket used, dirtiness of cows...). It is suggested that a close monitoring of herd management practices may allow the indirect control of milk quality parameters, thereby avoiding costly analyses of numerous smallholder milk deliveries.