Estimation of genetic parameters for growth traits and Kleiber ratios in Boer x Central Highland goat

Tropical Animal Health and Production - Accurate performance evaluation and genetic parameters estimation are the prerequisites for any successful genetic improvement program. This study was...     

Genetic diversity and matrilineal genetic origin of fat-rumped sheep in Ethiopia

Ethiopia is home to a diverse gene pool of indigenous sheep populations. Therefore, a better understanding of genetic variation holds the key to future utilization through conservation. Three of these breeds, Afar, Blackhead Somali, and Hararghe Highland, are found in eastern Ethiopia where they contribute significantly to the livelihood of most pastoralist, agro-pastoralist, and smallholder farmers. These indigenous sheep are recognized on the basis of morphotype and their genetic distinction remains unknown. Here, to assess genetic variation, and matrilineal genetic origin and relationship of fat-rumed sheep found in eastern Ethiopia, 300 individuals from the three breeds were genotyped for 22 microsatellite markers and sequenced for the mitochondrial DNA displacement loop (mtDNA d-loop) region. The overall H_O and H_E were 0.57 and 0.75, respectively. Differentiation statistics revealed that a high proportion (97%) of the total genetic variation was explained by differences between individuals within populations. Genotype assignment independent of the population of origin showed K?=?2 to be the optimum number of genetic backgrounds present in the dataset. This result was further confirmed by mtDNA D-loop sequences comparison in which the matrilineal genetic origin of eastern Ethiopia sheep is from two haplotype groups (types A and B) among the five haplotypes globally observed. Taken together, our findings suggest that the sheep populations from three breeds originated from two ancestral genetic backgrounds that may have diverged prior to their introduction to Ethiopia. However, to obtain a complete picture of the evolutionary dynamics of Ethiopian indigenous sheep, more samples and populations from within and outside of the country will need to be analyzed.

     

埃塞俄比亚的中央高地房屋建筑木材消费和树种偏好-提高树木种植的意义

2008年间在埃塞俄比亚高原调查房屋建筑木材消费和树种偏好情况,以及森林产品建设的策略和未来利用的可能性。对36座农家住户其中包括24座铁皮屋顶的房子和28座茅草盖顶的房子为对象进行调查,研究建筑木材的种类、材积和来源。结果表明,平均一座房屋的每57m^2地面空间面积需消耗木材13．7m^3。地面空间面积和木材消耗量的变化随房屋种类而变化。平均一座铁皮屋顶的房屋的每51．9m^2地面空间面积需消耗木材16．8m^3,平均一座茅草盖顶的屋顶每286m2地面空间面积需消耗木材3．2m^3。家庭和地面空间面积的大小是影响建筑木材消耗的主要因素。平均一座住房需消耗木材种类分别为,9．3％非洲铅笔柏（Juniperus procera）、5．6％墨西哥落羽杉（Cupressus Iusitanica）、29．2％蓝桉（Eucalyptus globulus）和26％赤桉（Eucalyptus camaldulensis）。由非洲铅笔柏（Juniperus procera）,墨西哥落羽杉和蓝桉来源的木材被限制。因此,目前木材短缺大约为59．5％。建议改进树木的种植方法来提高木材量,同时可研制土壤砖当作建筑材料的替代品。     

Exploiting the diversity of barley landraces in Ethiopia

The paper describes a methodology to incorporate the collection of barley landraces available in the Plant Genetic Resources Centre of Ethiopia (PGRC/E), as well as future collections, in the Ethiopian barley breeding program. Six hundred pure lines extracted from thirty Ethiopian barley landraces were evaluated and selected, along with the original populations, between 1989 and 1993. Three lines were identified which significantly outyielded the local landrace in some of the testing sites and had a higher average yield across sites and seasons. The yield of these lines was similar to the best improved variety also developed from a landrace population. Despite the relatively small number of landrace-lines (600) in the original population, the exploitation of the diversity existing within Ethiopian barley germplasm has produced in only five years promising lines for yield at low input conditions and for disease and insect resistance. Some lines had a yield potential comparable with the best breeding lines produced earlier, and one is under multiplication for release.     

Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia

A cross-sectional study was carried out from November 2010 up to April 2011 to estimate mastitis prevalence and associated risk factors and to assess its bacterial causes in traditionally managed camels in Borana Zone, Southern Ethiopia. Thus, 348 lactating camels were examined clinically, and subclinical cases were checked with California mastitis test (CMT). The overall prevalence of mastitis was 44.8 % (156/348), comprising clinical (19, 5.4 %) and subclinical (137, 39.4 %) cases. The quarter level prevalence of mastitis was 24.0 % (334/1,392). Of the total 1,392 examined teats, 30 were blind, and hence, from the 1,362 non-blind CMT-examined teats, 22.3 % (304/1,362) were CMT positive. Of the 304 CMT-positive samples, 264 were culture positive (197 Gram-positive, 41 Gram-negative, and 26 mixed isolates), and 40 were culture negative. The prevalence of Staphylococcus aureus was found to be the highest at both the animal (12.8 %, 39/304) and quarter level (2.9 %, 39/1,362). Regression analysis revealed higher likelihood of mastitis occurrence among camels from Dharito (OR?=?3.4, 95 % confidence interval (CI)?=?1.8, 6.4), Gagna (OR?=?3.4, 95 % CI?=?1.8, 6.5), and Haro Bake (OR?=?2.6, 95 % CI?=?1.3, 5.1) than camels from Surupha. Likewise, there was higher chance of mastitis occurrence among camels at the early lactation stage (OR?=?2.3, 95 % CI?=?1.1, 4.6) and camels with udder/teat lesions (OR?=?13.7, 95 % CI?=?1.7, 109.4) than among camels at late lactation stage and camels with healthy udder/teats, respectively. In conclusion, this study reveals the current status of camel mastitis in Southern Ethiopia.     

Performance and limitation of two dairy production systems in the North western Ethiopian highlands

In order to characterise the dairy production systems as well as the productive and reproductive performance of dairy cows in the study area, a total of 256 and 54 dairy farms were used for survey and monitoring data collection, respectively. Based on breed, land size, feed and market accessibility, two major dairy production systems were identified: a rather specialized, urban, and a peri-urban dairy production system. Urban farmers owned larger herds but farmed less land, and sold a greater proportion of liquid milk than peri-urban farmers, who processed more milk. Purchased feed played a more important role for the feed supply of urban than peri-urban farms. Significant breed effects were found for productive and reproductive performance traits. It is concluded that improved breeding and health management, genetic improvement of local breeds and supplementation of poor quality feed resources are the key factors for enhancing productivity of dairy cows and thereby increasing family income from milk production.     

Effect of liming and applied phosphorus on growth and P uptake of maize (Zea mays subsp.) plant grown in acid soils of West Wollega,Ethiopia

The study aimed at investigating effects of lime and mineral P fertilizers on P uptake and growth of maize (Zea mays subsp.) in greenhouse pot experiment. Combination of four P rates and four lime rates were applied to four highly acidic soil samples and the soils were incubated for a total of 112?days after which maize (Zea mays subsp.) was planted. The maize plants were harvested for analysis after 42?days of growth. Control experiments were also included. Available P (Bray I) and pH were significantly increased after incubation. Maximum available P was obtained in the soils that received the highest P rate and optimum lime rate. Levels of exchangeable acidity were significantly decreased in the P and lime treated soils compared to the control experiments. Plant biomasses and P uptake of maize increased significantly (p?≤?0.001) with application of P and lime compared to the control experiments.     

On-farm diversity of common bean (Phaseolus vulgaris L.) varieties in east Hararghe Zone,Eastern Ethiopia

Genetic Resources and Crop Evolution - Common bean (Phaseolus vulgaris L.) is an important source of food and income. However, its on-farm diversity and conservation by smallholder farmers is not...     

Adult neurogenesis in the mammalian dentate gyrus

Earlier observations in neuroscience suggested that no new neurons form in the mature central nervous system. Evidence now indicates that new neurons do form in the adult mammalian brain. Two regions of the mature mammalian brain generate new neurons: (a) the border of the lateral ventricles of the brain (subventricular zone) and (b) the subgranular zone (SGZ) of the dentate gyrus of the hippocampus. This review focuses only on new neuron formation in the dentate gyrus of the hippocampus. During normal prenatal and early postnatal development, neural stem cells (NSCs) give rise to differentiated neurons. NSCs persist in the dentate gyrus SGZ, undergoing cell division, with some daughter cells differentiating into functional neurons that participate in learning and memory and general cognition through integration into pre-existing neural networks. Axons, which emanate from neurons in the entorhinal cortex, synapse with dendrites of the granule cells (small neurons) of the dentate gyrus. Axons from granule cells synapse with pyramidal cells in the hippocampal CA3 region, which send axons to synapse with CA1 hippocampal pyramidal cells that send their axons out of the hippocampus proper. Adult neurogenesis includes proliferation, differentiation, migration, the death of some newly formed cells and final integration of surviving cells into neural networks. We summarise these processes in adult mammalian hippocampal neurogenesis and discuss the roles of major signalling molecules that influence neurogenesis, including neurotransmitters and some hormones. The recent controversy raised concerning whether or not adult neurogenesis occurs in humans also is discussed.