香蕉茎叶对母牛繁殖性能影响的研究

[目的]为研究香蕉茎叶对母牛繁殖性能的影响,[方法]采用比较法,对饲喂香蕉茎叶和玉米秸秆青贮能繁母牛间的繁殖性能及犊牛的生长发育的差异进行了对比。[结果]研究结果表明,在相同的饲养管理条件下两组母牛的繁殖性能和犊牛的生长发育情况无明显差异。[结论]与肉牛常规饲料——玉米秸秆青贮相比,长期饲喂香蕉茎叶青贮饲料对能繁母牛繁殖性能、对胎儿和犊牛的生长发育不会产生不良影响,可以部分或完全替代玉米秸秆饲料,来降低母牛的生产成本,提高母牛的养殖效益。     

Production d'un Syndrome Débilitant chez le Hamster après L'inoculation de Matériel Leucémique Bovin

Wasting disease was observed in hamsters inoculated at birth with a cell-free bovine leukemic extract. The autopsy and histological examination of the runted hamsters revealed visible lesions in the lymphoid tissues. These lesions consisted mostly in depletion of lympocytes in the spleen and in the cortex of the lymph nodes and in atrophy of the Peper's patches. Thymic lesions were also observed. Anemia and a decrease of circulating lymphocytes were observed in the peripheral blood.     

A Selective-Differential Medium for Detection of Streptococcus Agalactiae

A practical culture medium which allows direct plating of milk samples for detection and differentiation of Streptococcus agalactiae within 48 hours is described. Most other micro-organisms likely to be present in these samples are inhibited. Although some strains of Staphylococcus species and ofStreptococcus faecalis are able to grow, they may be differentiated on the basis of reaction in the medium surrounding the colonies.     

A survey of the selenium status of beef cows in Alberta.

An epidemiological survey was conducted in Alberta to measure the selenium status in blood of beef cows during the fall and to determine the risk of selenium deficiency among specific geographic regions of Alberta. Three census divisions of Alberta based on the Statistics Canada Census of Agriculture were chosen as the study areas for the project. Soils and plants in area A (Edmonton area) and area B (Calgary area) were known to be deficient in selenium, while soils and plants in area C (southeast corner of Alberta) were known to have adequate levels of selenium. Blood samples were collected from 335 cows on 29 farms from the 3 study areas. These samples were collected from cows that had recently been removed from pasture in October and November 1992. Answers to a short questionnaire pertaining to various herd characteristics and management practices were also obtained for each herd. The average value of selenium for all cows sampled was 2.20 mumol/L. The average value of selenium of cows in areas A and B was 1.93 mumol/L. The average value of selenium of cows in area C was significantly (P < 0.05) higher at 2.70 mumol/L. Nine percent of the cows in the study were considered marginal or deficient in selenium (< 1.27 mumol/L selenium). Herds located in area C, herds that were provided with supplemental feed on pasture, and herds that were pregnancy checked had higher average herd selenium values than did other herds. Cow-calf producers located in areas with selenium-deficient soils should pay particular attention to selenium supplementation for their cows. Some of the negative "geographic" effects on selenium values can be overcome by more progressive management practices.     

我国西藏四种植物染色体数目观察

本文对西藏四种植物进行染色体观察，这四种植物的染色体数目均为国内外首次报道。     

Seroprevalence of leptospiral antibodies among dairy cattle kept in communal corrals in periurban areas of Bamako, Mali, West Africa

Sera obtained from dairy cattle in communal corral herds located near the city of Bamako in Mali, West Africa were sceeened using the microscopic agglutination test against 26 serovars representing 15 serogroups of Leptospira interrogans. Forty five percent (44.8%; 288/642) were positive to one or more serovars. This seroprevalence rate likely reflects infection since vaccination against leptospiral infection has not been practiced i Mali. The rate was higher among females. The most common titers were against antigens of serovars cynopteri (14.7%), hardjo (13.3%), pomona (9.2%), nona (8.1%), kambale (6.5%), grippotypyosa (6.4%), hebdomadis (6.2%), and pyrogenes (5.2%).     

Echocardiographic evidence for myocardial failure induced by taurine deficiency in domestic cats.

Dietary taurine-deficiency is a cause of dilated cardiomyopathy (DCM) in cats. While the incidence of clinical cases of feline DCM has markedly decreased since the association between DCM and taurine-deficiency was first recognized, not all cats maintained on taurine-deficient diets develop DCM. The objective was to temporally evaluate left ventricular (LV) function using M-mode echocardiography in 23 cats maintained on a taurine-deficient diet; 20 time-matched, taurine-supplemented cats served as controls. The duration of feeding trials ranged from 6-15 months. No diminution of myocardial function was recorded in a small number of taurine-deficient cats whereas cardiac performance in some taurine-deficient cats diminished to levels characteristic of DCM. Of the taurine-deficient cats, 17 (74%) experienced a greater than 25% reduction in fractional shortening and 21 (91%) had a greater than 25% increase in LV end-systolic short-axis diameter. On average, LV end-systolic short-axis diameter increased by 70% and fractional shortening decreased by 37% in taurine-deficient cats. Mean velocity of circumferential fiber shortening was similarly reduced in taurine-deficient cats. The greatest rate of change in M-mode echocardiographic variables occurred during the first four months on the taurine-deficient diet. Dietary taurine deficiency leads to a spectrum of changes in myocardial function in domestic cats. While DCM is observed in some cats, decreased systolic pump function and increased LV end-systolic short-axis diameter are more consistent findings.