不同钼铜水平下肉牛铜需要量的研究

选择年龄、体重相近,健康利木赞×鲁西黄牛杂交一代公牛4头,在不同钼铜水平下,研究肉牛血液铜的代谢规律和铜需要量。试验分低钼(基础日粮钼含量0.27mg/kg)和高钼(基础日粮+钼5 mg/kg)两个水平进行。研究结果表明:低钼水平下,日粮干物质中添加铜10、25和50mg/kg,血液铜水平在0.97～1.18mg/kg之间,各水平间无差异,证明日粮中添加10mg/kg铜即可满足肉牛的需要。高钼水平下,血液铜含量随着铜添加量的增加而变化较大,加10mg/kg铜时血液铜水平在0.8mg/kg以下,不能满足牛的需要;添加铜25和50mg/kg时,血液铜水平上升到1.0mg/kg左右,并能满足牛对铜的需要,而添加25和50mg/kg血液铜无差异,证明高钼时添加25mg/kg才能满足肉牛铜的需要量。本研究还证明,肉牛铜营养状况可用以下回归公式预测:低钼:Y=24.33X4.39(R=0.991,n=3);高钼:Y=61.84X2.58(R=0.923,n=3)。式中:Y-日粮铜水平;X-血液铜水平。     

The effect of peri-parturient anthelmintic treatment on the productivity of dairy cattle in subtropical western India

Trials with fenbendazole (Panacur, Hoechst India Ltd) were carried out on two commercial farms in subtropical western India to study the response and economics of nematode treatment in adult dairy cows. Milk yield, lactation length, time to first oestrus and worm egg output were monitored in treated and control groups. Treatment reduced the egg count considerably. Treated cows produced 142 litres more milk over 100 days (p<0.05), with extension of lactation length and advancement of time to first oestrus. The economic gain in terms of milk yield far outweighed the cost of anthelmintic used.     

Polymorphonuclear neutrophil leukocyte function in clinical bovine patients and in cows with or withoutStaphylococcus aureus mastitis

A fluorochrome microassay was used to investigate peripheral blood polymorphonuclear leukocyte (PMNL) function in cattle. Glass-adherent PMNL were reacted withStaphylococcus aureus princubated in 20% bovine serum for 30, 60 and 90 min. Coverslips were stained with acridine organge (AO) followed by crystal violet to quench extracellular bacterial fluorescence. PMNL function was evaluated by counting the number of dead (stained red with AO) and live (stained green with AO)S. aureus contained within 100 PMNL. A phagocytic index was calculated as the average number of bacteria contained within PMNL. The percentage killing ofS. aureus was calculated from the average proportion ofS. aureus within PMNL that were dead.Six clinically normal Holstein calves, 3–4 months of age, were sampled on 6 consecutive days. PMNL phagocytosis and killing did not vary significantly (p>0.05) among repeated samplings per calf. PMNL function increased with increasing time of incubation of PMNL withS. aureus. Means (± SD) for percentage killing were 46.7±13.1, 57.4±11.6, and 62.1±9.8% for 30, 60 and 90 min of reaction, respectively. Means (± SD) for the phagocytic index were 2.9±0.8, 3.6±1.0, and 4.2±1.1 bacteria/PMNL for 30, 60 and 90 min of reaction, respectively. PMNL function was determined in 30 normal cattle of various breeds, age and sex, and these values were pooled to provide normal values for PMNL function.When values for bovine clinical patients (n=25) with various diagnoses were compared with normal values (defined by the mean ± 2SD for the 30 normal cattle) for PMNL function, only one patient was observed to exhibit PMNL hypofunction. A cow with disseminated intravascular coagulation in association with peracute coliform mastitis exhibited decreased PMNL killing capacity. Abnormal PMNL function was uncommon in the hospital population studied.Peripheral blood PMNL function was evaluated in lactating Holstein cows with (n=15) or without (n=15) chronic subclinicalS. aureus mastitis. There was no significant (p>0.05) difference in PMNL function among these cows.     

关于牛胴优质分割肉块名称的讨论

随着优质肉牛生产技术的示范与推广，肉牛产业化蓬勃发展，但在生产过程中，很多牛胴优质分割肉块名称使用不太规范，亟待统一名称，以促进全国肉牛业的进一步发展。     

不同收获期玉米青贮干物质在奶牛瘤胃内降解率的研究

本文采用随机实验设计，利用瘤胃尼龙袋技术，测定全株玉米青贮分剐在乳熟、腊熟期收获时其干物质(DM)在奶牛瘤胃的降解率。结果表明：各期DM在奶牛瘤胃降解率依次为40．22％、53．24％。测试结果证明，在黑龙江省东部地区，腊熟期收获的全株玉米青贮对奶牛的饲用价值较高。     

盘江黄牛育肥效果分析

选择健康无病、体格相近，不同年龄的盘江黄牛24头平均分为4组，其中2岁牛2个组(A、B组)，成年牛2个组(C、D组)，随机将4组牛分为高精料喂量组和低精料喂量组，以研究不同年龄盘江黄牛在育肥过程中给以不同精料日喂量时，其增重能力及育肥效益试验结果，在同喂高精料日粮状况下，2岁牛平均日增重显著低于成年牛日增重(P＜0．05)；在日粮精料量不同时，高精料喂量组牛的增重速度显著高于低精料喂量组(P＜0．05)。表明，牛的采食能力和饲料营养水平是影响肉牛增重的重要因素，日粮的精料喂量也在一定程度上决定肉牛的增重速度。     

奶牛重要营养素--水

本文主要介绍了水在奶牛营养中的重要作用、奶牛饮水量的计算以及影响奶牛饮水量的因素。     

A cross-sectional study of bluetongue virus and Mycoplasma bovis infections in dairy cattle: I. the association between a positive antibody response and production efficiency

In a cross-sectional study of bluetongue virus (BTV) and Mycoplasma bovis (M. bovis) infections, a sample of 572 California dairy cows was tested for the presence of antibodies to answer the question: Is it possible to identify and to assess quantitatively the associations between positive antibody test and production? Serum samples collected from these cows during December 1986 were tested for the presence of antibodies to BTV and M. bovis using the enzyme-linked immunosorbent assay (ELISA). Data on milk production were extracted from individual cow sheets of the California Dairy Herd Improvement Association (DHIA) record-keeping system and interfaced with percentage ELISA results for analysis. Univariate and multivariate statistical analyses, using the X ² test for categorical variables or Student's t-test for continuous variables and multiple logistic regression respectively, were carried out to evaluate for possible associations between positive antibody tests to each agent and each production variable of interest. Complete data on all variables studied were obtained for 289 (50.5%) cows for M. bovis and 423 (74%) cows for BTV. For cows with complete data on all variables, estimates of the point prevalence of antibodies to BTV and M. bovis were 70.5% and 66.1%, respectively. Results of this study indicated that Guernsey cows were more likely to have a positive BTV test than Holstein cows and that cows in higher lactations were more likely to test positive to BTV ELISA than those in lower lactations (p<0.05). Because all cows except those on one farm were Holstein, our confidence in the effect of breed is limited. The association between lactation number and BTV seropositive test may be an age factor identified earlier in the study. For M. bovis, the results of the analysis indicated that seropositive cows were more likely to produce less milk, on a mature equivalent basis (OR_adj=0.96, p=0.034), and that they had less extended 305 day milk production potential (OR_adj=0.90, p<0.0001) than seronegative cows.     

Occurrence of Coxiella burnetii in Polish dairy cattle herds based on serological and PCR tests

The aim of the research was to assess the prevalence of antibodies to Coxiella burnetii in dairy cattle herds in Poland and to compare the results of real-time PCR and ELISA tests performed on bulk tank milk (BTM) samples. In total, 2635 serum samples collected from 969 dairy cattle herds from all provinces were tested using ELISA. Additionally, BTM specimens from 101 herds were analysed by ELISA and real-time PCR targeting IS1111 element. Presence of anti-C. burnetii antibodies was confirmed in 25.39% of serum samples in 237 herds (24.46%) and the herd-level seroprevalence in Voivodeships varied from 2.5% to 61.4%. Moreover, 46 (45.5%) of analysed bulk tank milk samples gave postive result in ELISA and microbial DNA was detected in 40 (39.6%) of tested herds. The comparative analysis of ELISA and real-time PCR results obtained for BTM samples using the chi-square test showed statistically significant relationship between results of both methods.