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Despite the wide distribution of natural stands of Acacia senegal in Ethiopia, commercial exploitation of gum arabic is constrained by lack of tapping and development techniques. We evaluated the gum arabic yield from natural stands of A. senegal and the growth of 6 provenances in different parts of the country. For the gum yield evaluation from natural stands, four tapping positions and three tapping seasons were tested in a factorial RCB design. The second experiment in Metema evaluated survival and growth of six provenances. A. senegal trees in natural stands respond well to tapping if tapped during the appropriate season and at the correct position on the tree. The mean gum yield did not vary significantly by tapping season (p=0.63). Higher mean yield was, however, collected from trees tapped in October (96 g·tree?1 per two harvests). The mean yield differed significantly (p=0.009) between the tapping positions. Mean separation (α=0.05) shows that trees tapped at mid stem gave higher yield (160 g·tree?1 per two harvests). The interaction effect of tapping season and position was not significant. Higher mean yield ((70 ± 112) g·tree?1) was recorded in mid October-mid stem in two harvests. The second experiment indicated statistically significant difference in mean survival (p=0.0298), height (p=0.000) and root collar diameter (RCD), (p=0.012) between the six provenances. Highest survival, height and root collar diameter growth was observed from Abderafi provenance (100%, (148±11) cm, (38±11) mm, respectively). We recommend October and mid-stem and branches as appropriate tapping season and position. We recommend planting of the Abderafi provenance for the study area due to its superior growth and survival. Our study contributes to the proper selection of provenances for plantation development and improved tapping technology for better production of gum arabic in the country. 相似文献
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Moisture-dependent physical properties of niger (Guizotia abyssinica Cass.) seed were studied at 5.60, 12.99, 19.77, 27.08 and 31.65% moisture content (wet basis). The length, width, thickness and geometric mean diameter increased significantly (p < 0.05) from 3.86 to 4.06 mm, 0.96 to 1.02 mm, 0.86 to 0.96 mm and 1.47 to 1.59 mm, respectively with increase in moisture content from 5.60 to 31.65% whereas the increase in sphericity from 38.10 to 39.01% was not significant. Similarly, thousand seed mass, porosity and angle of repose increased (p < 0.05) linearly from 2.50 to 3.69 g, 41.76 to 47.65% and 29.86° to 39.12°, respectively with increase in moisture content under the experimental condition. The bulk density decreased significantly (p < 0.05) from 635.23 to 561.06 kg m?3 with increase in the moisture content range considered in the study, whereas the true density showed a slight increase from 1090.71 to 1098.42 kg m?3 with increase in moisture content from 5.60 to 27.08% followed by a drop from 1098.42 to 1071.75 kg m?3 as moisture content increased from 27.08 to 31.65%. Coefficient of static friction increased (p < 0.05) logarithmically from 0.34 to 0.51, 0.38 to 0.56 and 0.13 to 0.53 on mild steel, plywood and glass surfaces, respectively with increase in moisture content from 5.60 to 31.65%. 相似文献
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Endalkachew Wolde-meskel Zewdu Terefework Åsa Frostegård 《Soil biology & biochemistry》2004,36(12):2013-2025
The diversity of 110 rhizobial strains isolated from Acacia abyssinica, A. seyal, A. tortilis, Faidherbia albida, Sesbania sesban, Phaseolus vulgaris, and Vigna unguiculata grown in soils across diverse agro-ecological zones in southern Ethiopia was assessed using the Biolog™ system and amplified fragment length polymorphism (AFLP) fingerprinting technique. By cluster analysis of the metabolic and genomic fingerprints, the test strains were grouped into 13 Biolog and 11 AFLP clusters. Twenty-two strains in the Biolog method and 15 strains in the AFLP analysis were linked to eight and four reference species, respectively, out of the 28 included in the study. Most of the test strains (more than 80% of 110) were not related to any of the reference species by both methods. Forty-six test strains (42% of 110) were grouped into seven corresponding Biolog and AFLP clusters, suggesting that these groups represented the same strains, or in some cases clonal descendants of the same organisms. In contrast to the strains from S. sesban, isolates from Acacia spp. were represented in several Biolog and AFLP clusters indicating the promiscuous nature of the latter and widespread occurrence of compatible rhizobia in most of the soil sampling locations. The results showed that indigenous rhizobia nodulating native woody species in Ethiopian soils constituted metabolically and genomically diverse groups that are not linked to reference species. 相似文献
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A study was carried out to estimate the prevalence, larval burden and risk factors of ovine and caprine oestrosis from December
2007 to May 2008 on 554 heads of randomly selected sheep and goat slaughtered at Ambo town, Western Shoa, Ethiopia. The results
show an overall prevalence of 59.9% with infection rate of 69.8% and 47.3% in sheep and goats respectively. No statistically
significant difference in the prevalence was noted with regard to the assumed risk factors like sex, nose color, face color,
horned versus polled, origin, and months (p > 0.05). Sheep were nearly twice more likely to be infected as compared to goats (p = 0.0001, odds ratio (OR) = 1.975). Age of the animals was found to be protective (OR = 0.579; 95% confidence interval = 0.393,
0.853; p = 0.006). As compared to very fat animals, poor (p = 0.040, OR = 4.834), medium (p = 0.049, OR = 4.198), and fat (p = 0.022, OR = 5.795) body condition animals are more likely to be infected by Oestrus ovis larvae. Nasal and sinus cavity pathology is positively correlated with the total larval count (r = 0.56, p < 0.0001). Out of a total of 3,770 larvae collected, 57.5% were L1, 30.8% L2, and 11.7% L3 larvae. All the three larval instars
were seen throughout the study months. It is concluded that oestrosis is a common problem in the study area and more prevalent
in sheep than goats, in adult than young, and in animals with poor body condition. 相似文献
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A study on seroprevalence of caprine brucellosis under three livestock production systems in southern and central Ethiopia 总被引：1，自引：1，他引：0
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Antimicrobial susceptibility test of 98 isolates of Salmonella was assayed from September 2003 to February 2004 using the guidelines of the National Committee for Clinical Laboratory Standards
(NCCLS).The result revealed that 32.7% of Salmonella isolates were resistant to one or more of the 24 antimicrobials tested. Generally resistance for 13 different antimicrobial
drugs was recognized. The most common resistance was to streptomycin (24/32, 75%), ampicillin (19/32, 59.4%), tetracycline
(15/32, 46.9%), spectinomycin (13/32, 40.6%) and sulfisoxazole (13/32, 40.6%). All the three Salmonella Kentucky isolates showed resistance to at least 8 antimicrobials. Out of the 12 Salmonella Braenderup isolates, 10 (83.3%) showed multidrug resistance to ampicillin, spectinomycin, streptomycin, sulfisoxazole, sulfamethoxazole/trimethoprim,
amoxicillin/clavulanic acid and trimethoprim. Among the 8 S. Hadar isolates 7 (86.5%) showed antimicrobial resistance. All the 6 S. Dublin isolates were resistant to carbadox (100%). All the 6 S. Haifa isolates were resistant for at least ampicillin, streptomycin and tetracycline. Up to ten different antimicrobial resistances
pattern was observed. Multiple antimicrobial drug resistance was observed in 23 Salmonella isolates (23.5%). The level of antimicrobial resistance was significantly higher for isolates from chicken carcass (18/29,
62.1%) and pork isolates (5/22, 22.7%) (p = 0.003). The findings of the present study ascertain that significant proportion
Salmonella isolates have developed resistance for routinely prescribed antimicrobial drugs and poses considerable health hazards to
the consumers unless prudent control measures are instituted. 相似文献
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Faeces samples collected from diarrhoeic dairy calves in the first 8 weeks of life were examined for the presence of 5 enteropathogens. The majority of the 108 diarrhoea cases occurred in the first 5 weeks of life and a commercial ELISA kit detected bovine enteric coronavirus (BEC) in 38.9%, serogroup A rotavirus (RV) in 16.7% and K99 (F5) fimbrial adhesin-positive Escherichia coli (K99 ETEC) in 11.1 per cent. Concurrent infections of these enteropathogens were detected in 14.8% of samples (30.8% of samples positive for these agents). No evidence of cryptosporidial infection was found using a differential staining method on faecal smears nor was salmonella excretion detected. On 2 of the 8 farms only BEC was present; the other 6 farms were positive for all 3 agents. It is concluded that BEC is the major infectious cause of neonatal calf diarrhoea in the Ethiopian dairy herds studied with RV and K99 ETEC also contributing to morbidity, either alone or as mixed infections. 相似文献
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Abraham Mekibeb Getaneh Endrias Zewdu Gebremedhin 《Tropical animal health and production》2017,49(4):697-705
Mastitis is among the most prevalent disease that contributes for the reduction of milk production in dairy herds. Although several published studies have estimated the prevalence of mastitis, variation among studies is great. The objective of the present meta-analysis was to provide a pooled estimate of the prevalence of overall, clinical, and subclinical mastitis in dairy cattle in Ethiopia. A pooled estimate was also conducted by potential risk factors. The literature search was restricted to studies published in English language from January 2002 to June 2016. Meta-analysis of 39 studies was done under random effects model using metafor package in R software. The pooled estimate of the overall prevalence of mastitis on cow-basis was found to be 47.0% (95% confidence interval [CI]?=?42.0, 52.0). The pooled prevalence with the 95% CI for clinical and subclinical mastitis was 8.3% (95% CI?=?6.5, 10.3) and 37% (95% CI?=?32.9, 40.7) respectively. There is a statistically significant and high heterogeneity of the prevalence estimates between published studies. The odds of occurrence of mastitis were higher in cows at early (odds ratio [OR]?=?1.6; 95% CI?=?1.4, 1.8) and late lactation (OR?=?1.3; 95% CI?=?1.2, 1.5) than mid lactation, in cows with 3–4 (OR?=?1.5; 95% CI?=?1.4, 1.7) and >4 parity number (OR?=?2.9; 95% CI?=?2.6, 3.4) than those with 1–2 parity number. Previous history of mastitis, floor type, milking hygiene, and udder injury had also statistically significant effect on pooled prevalence of mastitis (P?<?0.05). The present study reported that there is high prevalence of mastitis in dairy cows in Ethiopia, which could contribute to the low productivity in lactating cows. The statistically significant association of risk factors such as floor type, milking hygiene, and presence of udder injury with mastitis may suggest that dairy farmers can reduce the occurrence of the disease by improving their management practices. 相似文献