Soil organic matter in Northern Ethiopia,current level and predicted trend: a study case of two villages in Tigray

Soil degradation resulting from permanent and high pressure on natural resources is a threat for the present and future of agricultural production in Ethiopia. Mono‐cropping, cultivation on steep slopes, use of cattle manure and crop residues as an energy source for cooking are common practices that have led to declining soil organic matter (SOM) contents. The objective of this research was to evaluate the current status of SOM in farmlands and exclosures (areas protected from grazing to allow their natural restoration) in Northern Ethiopia and to explore the long‐term effects of current agricultural practices and an improved scenario on SOM. At present, the SOM content of farmland soils is small, ranging from 2.1% to 2.9%, while exclosures showed a significant recovery after 20 yr of protection, with SOM contents ranging from 2.6% to 5.6%. However, the level of SOM in farmland soils is envisaged to decline given current agricultural practices, that is removal of crop residues and use of manure as an energy source for cooking. We found that applying manure alone appeared to be insufficient to revert this trend, due to limited availability and its alternative uses. Therefore, a multidisciplinary approach including improved manure and compost management needs to be supplemented with energy saving techniques, as fuel use is currently the largest competing claim for organic matter in the area.     

Antimicrobial prophylaxis in canine surgery

In 1961, Burke showed that antibiotics affect primary wound infections favourably only if they are administered before or shortly after bacterial contamination. The effect is optimal if there is already an effective tissue concentration at the time of contamination. During surgery the animal's resistance is strongly reduced, and consequently an infection may be caused by an inoculum present in a rather low concentration, at least lower than in normal circumstances. This reduced resistance lasts until only a few hours after operation. Prophylactic use of antibiotics therefore needs to be continued only for a short time after the final stage of the operation. A great number of clinical trials in human surgery have shown that short term peri-operative prophylactic use of antibiotics causes a reduction in the incidence of post-operative septic complications, in certain categories of operations and in selected groups of patients. Until properly designed, prospective, randomized and controlled clinical trials have been done in small animal clinics, it seems sensible to apply the abundant results from research with experimental animals and from clinical trials in human medicine to small animal surgery. Prophylactic use of antibiotics is indicated if the infection risks or dangers of possible complications are greater than the disadvantages of regular use of antibiotics. The risk factors in the development of wound infections and the choice of antibiotics are discussed.     

Gastric squamous cell carcinoma in three horses

Gastric squamous cell carcinoma was diagnosed in three horses. Clinical signs observed in all cases were weight loss, anorexia and lethargy. Respiratory signs were prominent in one case. All three horses had depressed albumin and elevated globulin and fibrinogen concentrations. Two horses were mildly anaemic. Inflammatory exudates were present in peritoneal cavities in all cases, and cytological evaluation provided a positive diagnosis of squamous cell carcinoma in two cases. Pleural fluid samples taken from two cases were also classified as inflammatory exudates, but no neoplastic cells were detected on initial examination. In all cases the neoplasms had arisen from the oesophageal region of the stomach, and had metastised throughout the abdomen. Two cases had metastatic lesions within the pleural cavity.     

Efficacy of metoclopramide for treatment of ileus in horses following small intestinal surgery: 70 cases (1989–1992)

Summary: In this retrospective study, postoperative ileus was studied in horses having resection of the small intestine followed by a jejunojejunal (n=35) or a jejunocaecal (n=35) anastomosis. Twenty-six horses received no metoclopramide, 27 received metoclopramide as an intermittent intravenous infusion and 17 horses received metoclopramide as a continuous intravenous infusion (0.04 mg/kg/hour). Horses receiving a continuous infusion of metoclopramide had a reduced total volume (P< 0.001), shorter duration (P< 0.001), and a slower rate (P< 0.001) of postoperative gastric reflux, and a shorter postoperative hospital stay (P< 0.01) when compared to horses receiving no metoclopramide and horses receiving metoclopramide as an intermittent infusion. Horses having jejunocaecostomy performed had a larger volume (P< 0.05), longer duration (P< 0.05), and a greater rate (P< 0.05) of postoperative gastric reflux, and a longer postoperative hospital stay (P< 0.001) than horses undergoing jejunojejunostomy. Horses that had an abdominal drain placed during surgery had a longer length of intestine resected (P< 0.05) and a longer postoperative hospital stay (P< 0.05) than horses without an abdominal drain. Horses that died or were euthanased during the postoperative period had a greater total volume (P< 0.05), longer duration (P< 0.05), and greater rate of postoperative gastric reflux (P< 0.01), a longer length of small intestine resected (P< 0.01), and a shorter postoperative hospital stay (P< 0.05) than horses that survived until discharge from the hospital. In a multivariate regression analysis the continuous infusion of metoclopramide was the only variable that contributed significantly to predicting the total volume (P< 0.001; r²= 0.24), duration (P< 0.001; r²= 0.24) and rate (P< 0.001; r²= 0.25) of postoperative gastric reflux. We concluded that metoclopramide given as a continuous intravenous infusion decreased the incidence and severity of ileus following small intestinal resection and anastomosis in horses.     

Relationships among Puberty,Muscle and Fat,and Liveweight Gain during Mating in Young Female Sheep

Greater depths of muscle are associated with better reproductive performance in ewe lambs, but, in adult ewes, reproductive performance also seems to vary with liveweight gain during the mating period. Therefore, in a large field study with Merino ewe lambs, we tested whether the relationships among eye muscle depth (EMD), fat depth (FAT) and reproductive performance depend on liveweight gain during the mating period. We selected lambs with a wide range in phenotypic values for depths of eye muscle (EMD) and fat (FAT) and assigned them to dietary treatments designed to achieve low (LOW, n = 244) or high (HIGH, n = 237) rates of liveweight gain during a 28‐day mating period. The LOW treatment maintained live weight, whereas the HIGH treatment gained 179 ± 3.8 g/day (p < 0.001). From those ewe lambs that attained puberty, first oestrus was detected at live weight 37.8 ± 0.2 kg and age 232 days. The proportion of ewes that attained puberty increased with EMD (p < 0.01). Ewes from the HIGH treatment were more fertile (pregnant ewes per 100 ewes exposed to rams) and had a higher reproductive rate (foetuses in utero per 100 ewes exposed to rams; p < 0.001) than those from the LOW treatment. Fertility and reproductive rate were positively correlated with weight gain during mating as well as live weight at the start of mating, FAT and EMD (p < 0.05 to <0.001). We conclude that faster growth, due to either extra nutrition during mating or higher phenotypic potential for fat and muscle, will increase reproductive performance in ewe lambs mated at 8 months of age.     

Time scales and heterogeneous structure in geodynamic earth models

Computer models of mantle convection constrained by the history of Cenozoic and Mesozoic plate motions explain some deep-mantle structural heterogeneity imaged by seismic tomography, especially those related to subduction. They also reveal a 150-million-year time scale for generating thermal heterogeneity in the mantle, comparable to the record of plate motion reconstructions, so that the problem of unknown initial conditions can be overcome. The pattern of lowermost mantle structure at the core-mantle boundary is controlled by subduction history, although seismic tomography reveals intense large-scale hot (low-velocity) upwelling features not explicitly predicted by the models.     

Detection of PrPSc in lung and mammary gland is favored by the presence of Visna/maedi virus lesions in naturally coinfected sheep

There are few reports on the pathogenesis of scrapie (Sc) and Visna/maedi virus (VMV) coinfections. The aim of this work was to study in vivo as well as post mortem both diseases in 91 sheep. Diagnosis of Sc and VMV infections allowed the distribution of animals into five groups according to the presence (+) or absence (−) of infection by Sc and VMV: Sc−/VMV−, Sc−/VMV+, Sc+/VMV− and Sc+/VMV+. The latter was divided into two subgroups, with and without VMV-induced lymphoid follicle hyperplasia (LFH), respectively. In both the lung and mammary gland, PrP^Sc deposits were found in the germinal center of hyperplasic lymphoid follicles in the subgroup of Sc+/VMV+ having VMV-induced LFH. This detection was always associated with (and likely preceded by) PrP^Sc observation in the corresponding lymph nodes. No PrP^Sc was found in other VMV-associated lesions. Animals suffering from scrapie had a statistically significantly lower mean age than the scrapie free animals at the time of death, with no apparent VMV influence. ARQ/ARQ genotype was the most abundant among the 91 ewes and the most frequent in scrapie-affected sheep. VMV infection does not seem to influence the scrapie risk group distribution among animals from the five groups established in this work. Altogether, these data indicate that certain VMV-induced lesions can favor PrP^Sc deposits in Sc non-target organs such as the lung and the mammary gland, making this coinfection an interesting field that warrants further research for a better comprehension of the pathogenesis of both diseases.     

应用GAR-HRP进行甘薯病毒NCM-ELISA检测试验

分别采用辣根过氧化物酶标记的羊抗兔抗体 (GAR -HRP)和碱性磷酸酯酶标记的羊抗兔抗体(GAR -AP) ,对甘薯羽状斑驳病毒 (SPFMV)、甘薯潜隐病毒 (SPLV)、甘薯轻斑驳病毒 (SPMMV)及甘薯褪绿病毒(SPCFV)进行NCM -ELISA检测 ,结果表明 ,采用GAR -HRP进行NCM -ELISA检测对于SPFMV、SPLV、SPM MV、SPCFV同样有效 ,且特异性高 ,重现性好 ,在某些方面优于GAR -AP。对于国内危害甘薯的SPFMV、SPLV等主要病毒 ,采用GAR -HRP进行ELISA检测更加经济有效 ,是切实可行的