Continuous monitoring of rumen pH - a case study with cattle

The use of a new pH probe for continuous rumen pH measurement was investigated in a preliminary study in cattle during a 10-day period. Two cannulated non-pregnant dairy cows were used together with two autonomous stomach probes, containing a commercial microelectrode and a reference-electrode with a pressure-equalizing system. By feeding diets with changing composition it was thought to provoke marked changes in rumen pH. Probes were programmed to sample pH and temperature every 30 s. During the entire experimental period, three daily rumen fluid samples were collected via the cannula as close to the probe as possible. Upon removal of probes, final calibration revealed only minor drifting of electrodes, that was significantly lower than results obtained during previous work with continuous measurement of gastric pH. After drift correction, the calculated absolute error of respective probe measurements for 11 sampling events was on average 0.08 pH for cow 817 (maximum 0.085 pH) and 0.14 pH for cow 686 (maximum 0.146 pH). pH measured by gastric probe was on average lower (i.e. more acid) than pH determined by tube sampling, with a mean difference of 0.33 pH (maximum 0.54) and 0.05 pH (maximum 0.5) for cow 817 and cow 686, respectively. The present prototype may thus play an important role in the development of a telemetric device for continuous monitoring of rumen pH in cattle and potentially other ruminants.     

Field method for monitoring blood glucose in beef cattle.

The purpose of this study was to determine the applicability of the Accu-Chek Easy (ACE) human self-monitoring system for monitoring glycemic status in cattle. The ACE method was compared with the Yellow Springs Instrument (YSI) analytical laboratory method in two studies. A preliminary study (62 samples) and a primary study (434 samples) involved a nine-fold range and a 10-fold range, respectively, of glucose concentrations obtained during the acute phase response of growing beef cattle to injections of varying dosages of endotoxin. The ACE monitoring method compared with the YSI analytical method resulted in similar patterns of glucose concentration change, similar ranking of glucose means across endotoxin dosages during hyper-and hypoglycemia, and a close relationship between paired YSI and ACE concentrations from common samples. The ACE method identified all nine animals that displayed hypoglycemic distress during the acute phase response to endotoxin injection. The relationship between the YSI analytical method and the ACE monitoring method was found to be nonlinear (YSI = -38.2+13.6.ACE.50; R2 = .99; Sy.x = 7.3 mg/dL), and the use of this equation to predict YSI values from ACE values in an independent data set resulted in linearity when YSI was regressed on the predicted YSI values (YSI = -.78+1.00.Predicted YSI; R2 = .87; Sy.x = 6.9 mg/dL). Even though variation seemed greater for ACE than for YSI, we concluded that a system developed for human self-monitoring of blood glucose, such as the ACE, can be used to monitor the glycemic status of cattle.     

Fistulization of the rumen in cattle

Various surgical techniques and two types of fistulas were tested when they were installed (Firm and PVC rumen cannulas were applied in 35 and 12 animals). We consider that the simplest process of installing the fixed rumen fistula is the total resection of abdominal wall together with peritoneum and following fixation of rumen to the abdominal wall with knot stitches and with removal of rumen wall between the stitches in the shape of circle. This process can be mastered by two people without particular equipment in approx. 30. minutes. When installing the PVC fistulas we prefer their fixation in rumen with help of seromuscular circular stitches followed by leading out the fistula off the main cut.     

牛瘤胃臌气的诊治

瘤胃臌气,中兽医叫“气胀”,俗称“肚子胀”,临床上较为常见．笔者在多年的临床实践中,用简单易行的自拟消胀汤治疗牛瘤胃臌气病20多例,疗效佳,花钱少,均获得满意效果。现报道如下,供同行参考。     

一例牛瘤胃酸中毒的诊治

瘤胃酸中毒多发生于牛,特别是奶牛.主要是精饲料喂量过多,精粗饲料比例不当所造成.以1～3胎的奶牛发病最多,7胎后的发病较少.一年四季均可发生,但以冬春季较多.临产牛和产后3 d内的发病较多.产奶量愈多,发病率愈高.笔者于2005年夏季带学生在临夏市某兽医站实习时遇到一病例,现将诊治情况总结如下.     

Development of a method for determination of cyanide concentrations in serum and rumen fluid of cattle

OBJECTIVES: To develop a reliable method for measurement of cyanide concentrations in cattle, using gas chromatography-mass spectrometry (GC-MS), and establish reference ranges of cyanide concentrations in cattle. ANIMALS: 52 Fleckvieh cattle. PROCEDURE: Cattle were allocated to 3 groups; 12 were fed leguminous grass and hay, 36 were fed whole-maize and corn-cob silages, and 4 were fed other feedstuffs. Samples of blood, rumen fluid, and liver were collected at time of slaughter. Serum, rumen fluid, and liver homogenate were assayed for cyanide content, using a derivatization procedure. A technique for analysis by GC-MS that used selected ion monitoring was developed. RESULTS: Compared with a spectrophotometric method, detection of cyanide in serum and rumen fluid by use of GC-MS was selective and sensitive, with a limit of detection of 0.7 microM. Spectrophotometric analysis yielded false-negative and false-positive results. Thus, the GC-MS method was used for subsequent analysis. In all cattle except 1, cyanide concentration ranged from < 0.7 to 35 microM in serum and from < 0.7 to 28 microM in rumen fluid; cyanide concentration in that 1 animal was 206 microM. Cattle fed clover, grass, grass hay, and clover hay had 8.3- to 8.6-fold higher mean cyanide concentrations in rumen fluid and serum than cattle fed whole-maize and corn-cob silages. CONCLUSIONS AND CLINICAL RELEVANCE: Results of this study suggest a reference range that should be useful for aiding in the diagnosis of cyanide poisoning. Also, cattle can apparently accommodate a serum cyanide concentration of 206 microM without adverse effects.     

奶牛瘤胃中小韦荣球菌的分离鉴定

采取健康奶牛瘤胃液,用小韦荣球菌特异性培养基从瘤胃液中初步分离小韦荣球菌,再用微量生化反应管和16S rDNA技术对分离菌株的生化特性和遗传特性进行鉴定,结合形态学观察结果判定所分离到的菌株为小韦荣球菌。     

Polyether ionophores--effect on rumen function in feedlot cattle

This article treated some of the modes of actions of ionophores in beef feedlot diets. It should be strongly emphasized that the predominant literature cited pertains to work with monensin sodium and more recently lasalocid sodium. There is ample evidence that the mode of action of these two ionophores is somewhat different and as new ionophores are cleared, it should not be assumed they follow the same mode of actions as described in this article.