奶牛真胃变位实验室诊断的研究进展

目前,真胃变位是奶牛常见的内科疾病之一,临床上主要与引发真胃扩张、真胃弛缓、神经元紊乱等因素相关.国内外许多学者报道了奶牛真胃变位在不同国家、同一国家不同地区、不同品种的年发病率.据统计,国外不同地区每年的发病率是0～7%,有些奶牛群发病率可达20%.     

Investigations on renal excretion of sodium in dairy cattle

Serum and urine were taken from healthy dairy cattle from 22 different farms. 214 animals belonged to the Swiss Brown breed and 210 were crossbreds of Simmental-Red Holstein. The animals were given at least 70 g of sodium chloride with their daily feed ration. On 6 farms sodium chloride was offered ad libitum in form of licks, which was presumed to be sufficient for covering their needs. Concentrations of sodium (UR Na), potassium (UR K) and creatinine were analyzed from serum and urine and fractional excretion of Na and K was calculated. Concentrations of sodium and potassium in urine from all cows (mean +/- sd) was 60.9 +/- 44.7 mmol/l and 370.7 +/- 66.9 mmol/l respectively. The FE values were 0.954 +/- 0.939% for sodium and 173.1 +/- 54% for potassium. In 5.5% of the animals values for UR Na < 10 mmol/l were found. There were no significant differences, however, were found in sodium and potassium excretion among farms. Urine samples of at least 10 animals should be analyzed in order to have a reliable estimation of the supply with sodium chloride within a herd. Our results do not support the hypothesis that low sodium excretion would be a predisposing factor for Bovine Dilative Cardiomyopathy in Simmental-Red Holstein cattle.     

Observations on the use of the 'Seralyzer' solid-phase clinical chemistry system in a veterinary hospital laboratory

Solid-phase clinical chemistry techniques coupled to a microprocessor-controlled reflectance photometer have been used alongside more traditional, mainly ‘wet’, methods of analysis for the estimation of glucose, urea, cholesterol, creatinine and haemoglobin. The instrument concerned, Ames Company's ‘Seralyzer’, was found to be precise, reliable and simple to use. Accuracy was good, but, as with any instrument primarily intended for use with human specimens, species normal values should be checked and re-adjusted where necessary.     

Investigations into the effect of two sedatives on the stress response in cattle

The effects of the sedatives acepromazine (an alpha-adrenergic antagonist) and xylazine (an alpha 2-adrenergic agonist) on plasma indicators of stress in cows were assessed after intramuscular injection and transport. After blood samples had been taken for baseline values, nine cows were given an intramuscular injection of saline (2.5 ml), acepromazine (0.05 mg/kg in 2.5 ml) or xylazine (0.05 mg/kg in 2.5 ml) on different occasions at least 1 week apart. The animals were then transported for 5 min by truck to a different environment and blood sampled for a further 1-3 h. There was a significant increase in plasma cortisol concentration (3.29 +/- 1.59 x baseline) after the injection of saline and transport. The injection of acepromazine also resulted in a significant increase in cortisol concentration (2.84 +/- 0.84 x baseline). There was no similar increase after injection of xylazine. This suggests that alpha 2-adrenergic receptors are involved in the response of plasma cortisol concentrations to stressors. An hyperglycaemic response occurred after xylazine (1.66 +/- 0.49 x baseline) and saline (1.20 +/- 0.1 x baseline) but not after acepromazine. Both sedatives produced a metabolic alkalosis (1.13 +/- 0.01 x baseline pH after xylazine and 1.034 +/- 0.02 x baseline pH after acepromazine). A greater decrease in haematocrit was seen after both sedatives (0.88 +/- 0.04 x baseline after xylazine, 0.81 +/- 0.08 x baseline after acepromazine) than after the injection of saline (0.97 +/- 0.06 x baseline).     

Preliminary system of rapid analysis of blood retinol level in cattle

Control of blood retinol levels in cattle during fattening is important in the production of marbled beef. However, it is difficult to easily measure the blood retinol concentration in the field. In this study, we attempted to develop an analysis method that does not require blood cell separation and uses a compact fluorescence analyzer that can be carried around as a preliminary system for measuring blood retinol concentration in the field. This system was used to monitor blood retinol levels in 12 fattening cattle (14 to 27 months old) and demonstrated a strong correlation (r = 0.78) with the results obtained by the standard high-performance liquid chromatography (HPLC) method. Stronger correlations (r = 0.87) were obtained until the cattle were 24 months of age. These results suggest that higher correlations can be expected to be obtained by improving the robustness of the extraction system. Refinements for practical use need to be considered, but whole blood extraction and the vitamin A analyzer that was developed show potential to be used for on-farm monitoring of retinol levels.     

Gamma-glutamyltransferase in the blood of cattle

Information is given on a long-term observation of gMT activities in the blood of cattle, aimed at using the results to interpret metabolic tests, especially tests of the function of liver. Dynamics of changes in the gMT activities was studied in the year seasons and the per cent activities in the decades (from 20 to 100 U per 1) in different groups of cows according to their reproduction cycle. In the part discussion relationships are given between the gMT activities and other findings obtained from metabolic tests. The average value of the gMT activities in the blood of a reference group of cows was 30.7 U per 1. The standard deviation was 7.01 U per 1. Reference limits for the gMT activities in the bovine blood serum - 16.7 to 44.7 U per 1 (95% interval of confidence) could be determined by a parametric statistical method. Average deviations of the gMT activities from those in the reference group of cows, expressed in histogram units J, ranged from 0.03 to 1.07 J after a long-term observation in particular calendar months. The maximum positive deviations were observed in January, June, July, November and they indicate the risk period, in August and September the values nearly approached those in the reference group of cows. The maximum positive deviation of the metabolic test amounted to 6.8 J (January). There were eight metabolic tests with the deviation greater than 1 J during the observation, two in the summer period (May--October) and six in the winter period (November-April). In cows after calving and in the first half of gravidity the gMT activities were most frequently in the decade 30.5-40.0 U per 1, and in highly pregnant cows in the decade 20.5-30.0 U per 1.     

A review of laboratory techniques and their use in the diagnosis of Leptospira interrogans serovar hardjo infection in cattle

SUMMARY This paper reviews the laboratory diagnosis of Leptospira hardjo infection in cattle. Two genotypes of L hardjo, Hardjoprajitno and Hardjobovis, have been identified in cattle, but only Hardjobovis has been isolated in Australia. There are problems with diagnosis and control of bovine leptospirosis. Infection is usually subclinical and the serological titres vary greatly in peak and duration. Leptospires may be excreted in urine for up to 18 months. Low microscopic agglutination test titres may be significant in unvaccinated herds as indicators of endemic infection. Vaccines differ in their composition, and their efficacy is difficult to evaluate. The serological response after vaccination is difficult to differentiate from the response after infection. Pregnant cows that become infected may abort, but this is usually after the serological response has peaked. Therefore, paired serum samples are of little use in diagnosing abortion caused by L hardjo. Fluorescent antibody techniques are more sensitive than dark field microscopy for detection of leptospires in urine and tissue samples. Techniques for culture have improved but are still difficult to perform and take 3 months or longer for results to be known. DNA probes and polymerase chain reaction tests are very sensitive and specific, quick to perform, and can be used on fluid and tissue samples.     

发酵活干菌处理秸秆育肥肉牛效果研究

发酵活干菌处理秸秆比未处理秸秆CP含量提高12．4％，60d饲养试验结果表明，秸秆经发酵活干菌处理后显著地改善了适口性，试验组牛的日均采食量和采食率分别比对照组牛提高30．9％和25．1％，日增重提高73．565，同期增加经济效益118．5元／头，具有较好的推广价值。     

Acid-base equilibrium in the blood in cattle in relation to the incidence of DFD (dark, firm, dry) meat

We studied changes in the parameters of the acid-base balance of the blood in cattle before animal transport to the slaughterhouses, after transport, after stunning and before bleeding. At the same time we studied the occurrence of DFD meat by measuring the pH value of the muscle and by determining the meat color. We found out that the disorder of acid-base balance was less manifest, with respect to the large capacity of the buffer systems of the blood, than the changes caused by glycogenolysis in the muscle.     

Distribution of T and B lymphocytes in mammary dry secretions, colostrum and blood of adult dairy cattle

The distribution of lymphocyte subpopulations from dry secretions, colostrum and blood from 10 healthy adult Hostein-Fresian cows was studied using the TH21A and B26A mouse monoclonal antibodies (MAb) to adult bovine B and T lymphocytes, respectively. The mammary gland lymphocytes (MGL) were isolated from composite sample of all four quarters by density centrifugation over discontinuous gradient of ficoll-diatrizoate. The peripheral blood lymphocytes (PBL) were purified using the ficoll-thrombin method. Isolated PBL and MGL were analyzed using the two fluorochromes method (TFM) and laser flow cytometry (LFC). The mean viability of isolated PBL and MGL from dry secretions and colostrum after the TFM and LFC were 92.4% +/- 3.2%, 91.4% +/- 6.0% and 87.1% +/- 6.1%, respectively. There was a good correlation between the two MAbs and the percentage of surface immunoglobulin (SIg) positive cells in the peripheral blood using the TFM. The PBL yielded a mean percentage of 21.2% B cells, 66.4% T cells and 9.4% "Null cells" (TH21A+; SIg-). The TFM on MGL from dry secretions and colostrum indicated two distinct patterns (group I and II) of SIg and reactivity to MAb markers (p less than 0.001). The MGL data included in group I and group II were gathered from both colostral and dry secretions. In comparison to the distribution of lymphocyte subsets within peripheral blood the mean percentages of B cells, T cells and "Null cells" in the mammary gland were respectively, 2.8%, 88.1% and 5.4% for group I and 3.5%, 89.0% and 15.1% for group II. In the mammary secretions, the use of SIg alone was not considered to be a good marker for B cells; in four animals a mean percentage of 15.6% (13.9/89.0 X 100) of the mammary gland T lymphocytes were also SIg+. Of the TH21A+ MGL, only 18.8% were SIg+ in group II compared with 34.1% for MGL from group I and 69.3% for the PBL. Marked differences in cell size distribution and cell surface antigen density were found when PBL and MGL from dry secretions were compared by LFC using the B26A MAb. The results of this study demonstrate a difference in the percentages of peripheral blood and mammary gland B and T lymphocytes and confirm previous findings in which the T lymphocytes were found to represent the major subpopulation of lymphocytes in bovine mammary secretions. This may represent an essential event in the adoptive transfer of cellular immunity through the colostrum in cattle.     

Effect of dry season supplementation of Sanga cattle in Zambia

Supplementation of lactating Sanga cows in central Zambia with low cost crop residues and urea-mineral licks resulted in significant increases in milk offtake (79%), total daily milk (86%), and daily liveweight gain of their calves (86%). At 1988 market prices the value of the additional milk (ZK54.00) and of liveweight of both cow and calf (ZK189.00) over the 13 weeks exceeded the estimated costs of inputs by ZK180.00.     

Investigations on the blood composition of sows during the reproductive cycle

Contents: In the second experiment of the series, a total of 217 blood and plasma samples, collected throughout pregnancy and in the four different seasons of the year, were analysed for 23 different cellular, gaseous, and biochemical parameters. Significant changes were noted during the terminal stages of pregnancy in the differential leucocyte count (lymphocytes and neutrophilic granulocytes), during mid-pregnancy in the level of plasma proteins, and, in early gestation, in the glucose concentration of the blood. The erythrocyte volume and mean corpuscular haemoglobin as well as parameters associated with the acid-base balance produced interactions between seasonal and gestational effects, generally indicating the additivity of the heat load and the stress of the terminal stages of pregnancy.     

Counterimmunoelectrophoresis in the serologic diagnosis of cysticercosis in cattle

Over the years 1983 to 1984 two-hundred and sixty-five bulls were examined during mass occurrence of bovine cysticercosis in one farm; out of this number 67 animals (25.3%) were confirmed autopsically as infected with cysticercosis. Counterimmunoelectrophoresis was used to examine the serum of slaughtered animals by help of two antigens--Taenia saginata and Taenia crassiceps. With T. saginata the sensitivity amounted to 44.8% and the specificity to 86.4%, with T. crassiceps to 28.3% and to 89.9%.