Efficacy of a modified polymerase chain reaction assay for detection of Ehrlichia canis infection.

Detection of Ehrlichia canis in acutely infected and convalescent dogs is important for effective treatment and control. However, accurate detection has been difficult to achieve, in part because dogs that have been treated therapeutically often remain seropositive for extended periods. A new method, polymerase chain reaction (PCR) assay using biotinylated E. canis-specific primers (PCR-BP), was developed for detection of E. canis. Four dogs experimentally infected with E. canis by intravenous inoculation of whole blood from carrier dogs and 2 naturally infected convalescent carriers were used to compare the specificity and sensitivity of the new method with that of microscopy/blood smear evaluation, serologic test, and conventional PCR assay using E. canis-specific primers. In experimentally infected animals, infection was detected as early as 7 days post-exposure using PCR-BP. Although the 2 naturally infected dogs were positive by serologic test and PCR-BP, both were negative by conventional PCR. Results suggest that the new method is a sensitive assay for detection of E. canis infection. In addition, results were obtained more rapidly than with other PCR-based assays.     

Assessment of the effects of different concentrations of ethylenediaminetetraacetic acid (EDTA) on erythrocytic indices of Nigerian White Fulani cattle and West African Dwarf goat

The aim of the study was to evaluate the effects of varying concentrations of ethylenediaminetetraacetic acid (EDTA) on blood samples from White Fulani breed of cattle and West African Dwarf goat from Nigeria. Sample sizes of 20 animals were used for both species. Different concentrations of EDTA (2, 4, 8 and 16 mg/ml) were used. The packed cell volume (PCV), red blood cell (RBC) and haemoglobin (Hb) concentration of blood samples collected from White Fulani breed of cattle and West African Dwarf goat into bottles containing 16 mg/ml of EDTA were significantly lower (P < 0.05) than those samples collected from the same animals into bottle containing 2 mg/ml (control). Similarly, the PCV, RBC and Hb values of the West African Dwarf goats in bottles containing 8 mg/ml of EDTA were significantly lower than those of the samples in the control (2 mg/ml). This study has shown that high concentration of EDTA as an anticoagulant can lead to a false erythrocytic index especially the PCV. In collecting blood samples for evaluation of haematological parameters, therefore, the blood volume/anticoagulant ratio must be strictly adhered to prevent error in the evaluated parameters in cattle and goats. Taken together, there is tendency for haemolytic anaemia to occur in blood sampled at higher concentration of anticoagulants in West African Dwarf goat than in White Fulani breed of cattle.     

Farmers’ knowledge of crop diseases and control strategies in the Regional State of Tigrai, northern Ethiopia: implications for farmer–researcher collaboration in disease management

Differences in perceptions and knowledge of crop diseases constitute a major obstacle in farmer–researcher cooperation, which is necessary for sustainable disease management. Farmers’ perceptions and management of crop diseases in the northern Ethiopian Regional State of Tigrai were investigated in order to harness their knowledge in the participatory development of integrated disease management (IDM) strategies. Knowledge of disease etiology and epidemiology, cultivar resistance, and reasons for the cultivation of susceptible cultivars were investigated in a total of 12 tabias (towns) in ten weredas (districts). Perception of diseases involved both scientific and spiritual conceptual frameworks. Of the more than 30 crop diseases recorded on the major crops in the region, only rusts and powdery mildews (locally called humodia) and a few root rots were considered by farmers to be important. Farmers’ awareness of other diseases was extremely low; some highly damaging but less conspicuous diseases, such as faba bean chocolate spot and chickpea ascochyta blight (also called humodia), were not regarded by farmers as disease but as problems caused primarily by excessive soil moisture. Considering that some of these “unrecognized” diseases can cause complete yield loss and genetic erosion in epiphytotic years, there is an urgent need for bringing together farmers’ and scientists’ knowledge to complement each other. Even when farmers had access to disease-resistant or disease-tolerant cultivars, they grew susceptible local varieties because of multiple criteria including earliness, good yield in years with low humodia severity, suitability for home consumption, market demand/quality, and low soil fertility and land management requirements. Farmer innovation and knowledge were evident in their use of diverse disease control measures, but these were a mixture of the “useful and the useless.” Our findings stress the necessity for extension workers and researchers to understand and improve farmers’ knowledge of crop diseases, and farmers’ ability to observe and experiment, through the Farmer Field School or a similar experiential learning approach. These insights about farmers’ knowledge of crop diseases provide a basis for further collaborative maintenance of crop genetic diversity, development of germplasm, and IPM-related research in Africa.

Effect of integrated management on Fusarium wilt progression and grain yield of chickpea in Syria

Fusarium wilt, caused by Fusarium oxysporum Schlechtend.: f. sp. ciceris (Padwick) Matuo & K. Sato, is a major production problem in many countries. A study was conducted to develop an integrated management of Fusarium wilt of chickpea using genotypes, sowing dates (January as early sowing and March/April as spring sowing) and fungicide seed treatments under natural infested plots in research plots and farmers’ fields 2007–2009 cropping seasons. In most cases, sowing date and fungicides did not affect disease parameters and seed yield. Chickpea genotypes showed significant differences in seed yield but different responses for disease parameters. Averaged over locations and seasons, the rate of disease development was higher in early (0.035 units day^?1) than spring (0.023 units day^?1) sowing. Chickpea genotypes showed different responses in affecting rate of disease development and cumulative wilt incidence in early and late sowing periods. Higher mean seed yield (1.3 t ha^?1) was recorded in early than late sowing (1.0 t ha^?1) of chickpea. The average seed yield reduction due to spring sowing ranged from 9% to 60% and highest yield losses were observed in FLIP-97–706 and Ghab-3. This study showed that integrating January sowing with genotypes having good levels of resistance for Fusarium wilt and Ascochyta blight helps farmers to narrow chickpea yield gaps in Syria.     

Evaluation of diet as a cause of gastric ulcers in horses

OBJECTIVE: To measure pH, volatile fatty acid (VFA) concentrations, and lactate concentrations in stomach contents and determine number and severity of gastric lesions in horses fed bromegrass hay and alfalfa hay-grain diets. ANIMALS: Six 7-year-old horses. PROCEDURE: A gastric cannula was inserted in each horse. Horses were fed each diet, using a randomized crossover design. Stomach contents were collected immediately after feeding and 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, and 24 hours after feeding on day 14. The pH and VFA and lactate concentrations were measured in gastric juice Number and severity of gastric lesions were scored during endoscopic examinations. RESULTS: The alfalfa hay-grain diet caused significantly higher pH in gastric juice during the first 5 hours after feeding, compared with that for bromegrass hay. Concentrations of acetic, propionic, and isovaleric acid were significantly higher in gastric juice, and number and severity of nonglandular squamous gastric lesions were significantly lower in horses fed alfalfa hay-grain. Valeric acid, butyric acid, and propionic acid concentrations and pH were useful in predicting severity of nonglandular squamous gastric lesions in horses fed alfalfa hay-grain, whereas valeric acid concentrations and butyric acid were useful in predicting severity of those lesions in horses fed bromegrass hay. CONCLUSIONS AND CLINICAL RELEVANCE: An alfalfa hay-grain diet induced significantly higher pH and VFA concentrations in gastric juice than did bromegrass hay. However, number and severity of nonglandular squamous gastric lesions were significantly lower in horses fed alfalfa hay-grain. An alfalfa hay-grain diet may buffer stomach acid in horses.     

Characterization of microbial populations and volatile fatty acid concentrations in the jejunum,ileum, and cecum of pigs weaned at 17 vs 24 days of age

In a series of five 17-d replicate trials, a total of 54 cannulated and 12 noncannulated pigs were used to determine the effects of weaning age (17 d or 24 d) on pH, dry matter percentage, aerobic and anaerobic microflora, lactate, and volatile fatty acid (VFA) concentrations in the jejunum, ileum, and cecum of weanling pigs. At -14 d of age, cannulated pigs were surgically fitted with T-cannulas in the jejunum (n = 20), ileum (n = 18), or cecum (n = 16). Upon weaning, cannulated pigs were individually caged in an environmentally controlled room with ad libitum access to a phase starter diet and water. Noncannulated pigs were killed at weaning and samples were collected from the jejunum, ileum, and cecum. Digesta and fecal swabs from cannulated pigs were collected twice weekly. The pH of cecal contents was lower (P < 0.05) and dry matter percentage was greater (P < 0.05) than those ofjejunal or ileal contents. Pigs weaned at 24 d of age had increased (P < 0.05) E. coli populations 3 d postweaning compared to preweaning populations, regardless of site of collection, whereas this increase was not observed in pigs weaned at 17 d of age. Unweaned pigs maintained higher (P < 0.05) lactobacilli populations compared to weaned pigs; however, populations declined (P < 0.05) in both groups by 3 d postweaning, with pigs weaned at 24 d of age having lactobacilli populations greater than pigs weaned at 17 d of age. Fecal populations of E. coli and lactobacilli declined (P < 0.05), whereas fecal bifidobacteria populations increased (P < 0.05) postweaning, regardless of weaning age. Concentrations of total fecal anaerobes declined (P < 0.05) in pigs weaned at 17 d of age but were maintained in pigs weaned at 24 d of age. Volatile fatty acid concentrations were greater (P < 0.05) in the cecum than in the jejunum or ileum, and acetic acid concentrations decreased (P < 0.05) postweaning regardless of weaning age. A tendency for L+ lactate concentrations to be greater (P < 0.07) in the ileum and jejunum vs the cecum was observed. Results indicate that weaning and weaning age have significant effects on microbial populations and VFA concentrations.     

Level of superoxide dismutase,glutathione peroxidase and uric acid in thioacetamide-induced cirrhotic rats

Levels of superoxide dismutase and glutathione peroxidase were determined in blood and hepatic tissues of thioacetamide-induced cirrhotic rats and compared to levels in age-matched control animals. The plasma level of uric acid was also determined in these animals. A general decrease was noticed in the level of all the antioxidants examined as compared to the control. This decrease was statistically significant in the level of all the antioxidants studied, except for the level of superoxide dismutase in blood. A decrease in the antioxidant level may indicate an increase in free radical level and thereby an increase in cellular damage in cirrhotic rats. The changes in the level of antioxidants showed a direct correlation with the changes in the level of trace elements observed in our previous studies. These studies suggest that antioxidants alone or in combination with trace elements may have beneficial effects in treating liver cirrhosis.     

Genetic and economic efficiency of integrating reproductive technologies in cattle breeding programme in Kenya

Tropical Animal Health and Production - We hypothesised that use of reproductive technologies (RTs) would result in increases in economic and genetic gains of a dairy cattle breeding programme. A...