Effects of different land use types on infiltration capacity in a catchment in the highlands of Ethiopia

Infiltration capacity is an important variable for understanding and predicting a range of soil processes. This study investigated for different slope positions the effects of forest conversion to cultivation and grazing on soil infiltration capacity. Infiltration capacity was measured in the field in each land use type using a double‐ring infiltrometer. A total of 108 soil samples (3 slope positions × 3 land use types × 4 soil profiles × 3 soil depths) were collected to determine the variables that affect infiltration capacity viz. particle size distribution, organic carbon content, dry bulk density and soil moisture content. The results showed that in the cultivated and grazed land compared with forest, infiltration capacity and soil moisture content were 70 and 45% smaller respectively, and dry bulk density was 13–20% larger. Changes in soil structure caused by surface soil compaction because of tillage and animal trampling coupled with a smaller soil organic carbon content, are likely to be the principal factors causing the decline in infiltration capacity and soil moisture content after conversion of forest to cultivation and grazing.     

Risk factors for bovine mastitis with the isolation and identification of Streptococcus agalactiae from farms in and around Haramaya district,eastern Ethiopia

Tropical Animal Health and Production - A cross-sectional study was carried out to determine the prevalence and risk factors of bovine mastitis caused by Streptococcus agalactiae from farms in and...     

Evaluation of Abattoir Inspection for the Diagnosis of Mycobacterium bovis Infection in Cattle at Addis Ababa Abattoir

Detailed postmortem examinations were conducted to evaluate the efficiency of meat inspection procedures and to determine the distribution of lesions in Mycobacterium bovis-infected cattle. The study involved routine inspection at slaughter, collection of tissues for detailed examination in the laboratory, and bacteriological examination to identify M. bovis. Additionally, a 10-year (1992--2001) meat inspection record was analysed to determine tuberculosis trends in the past decade. chi2-Test and simple regression were used to analyse the data. Out of 1350 cattle examined, 1.5% were found with tuberculous lesions. Routine abattoir inspection detected only 55% of cattle with confirmed lesions. Fifty-four per cent of tuberculous lesions were found in the lungs and thoracic lymph nodes, 23% in the lymph nodes of the head, and the remaining 23% in the mesenteric and other lymph nodes of the carcase. M. bovis was additionally isolated from an animal that had no gross lesions of tuberculosis. On average, the annual rate of whole-carcase condemnation due to generalized tuberculosis was 0.024% and it has increased annually by 0.34% over the past decade. The rate of whole-carcase condemnation indicates a high degree of TB transmission and requires immediate attention from both the economic and public health points of view. The lower sensitivity of routine abattoir inspection confirms the importance of improving necropsy procedures.     

Soil property changes following conversion of acacia woodland into grazing and farmlands in the Rift Valley area of Ethiopia

Continued conversion of woodlands into grazing and farmland is seriously undermining the natural ecosystem of the dry and fragile Rift Valley areas of Ethiopia. This study investigated the effects of land‐use change on soil organic carbon (SOC), total nitrogen (N), pH, exchangeable bases, cation exchange capacity (CEC) and base saturation (per cent) in three adjacent land‐use types: controlled grazing, open‐grazing and farmland. A total of 81 soil samples were collected and analysed. Contents of SOC and total N decreased drastically in open‐grazing and farmland (p < 0·001), and were significantly higher in the top 0·2 m than in the subsurface soil layer. Compared with the controlled grazing, reductions in the contents of SOC and total N in the top 1 m soil layer were 22–30 and 19 per cent, respectively, due possibly to the decrease in plant biomass input into the soil and the fast decomposition of organic materials. Long‐term cultivation had significantly increased the concentration of exchangeable K. Exchangeable Na was high in the lower layers, while Mg was higher in the top surface soil. CEC also varied with soil depth (p = 0·016); it was higher in the topsoil than in the subsurface soil, which may be, among others, due to the differences in soil organic matter distribution with depth. Although these semi‐arid soils are known to have low organic carbon and CEC levels, the values from the current study area are critically low, and may indicate the further impoverishment of the soils under high agricultural and grazing pressures. Copyright © 2010 John Wiley & Sons, Ltd.     

Alpha‐Linolenic Acid Supplementation in Tris Extender Can Improve Frozen–Thawed Bull Semen Quality

The study was conducted to evaluate the effects of α ‐linolenic acid (ALA) on frozen–thawed quality and fatty acid composition of bull sperm. For that, twenty‐four ejaculates obtained from three bulls were diluted in a Tris extender containing 0 (control), 3, 5, 10 and 15 ng/ml of ALA. Extended semen was incubated at 37°C for 15 min, to allow absorption of ALA by sperm cell membrane. The sample was chilled for 2 h, packed into 0.25‐ml straws and frozen in liquid nitrogen for 24 h. Subsequently, straws were thawed and evaluated for total sperm motility (computer‐assisted semen analysis), membrane functional integrity (hypo‐osmotic swelling test), viability (eosin‐nigrosin), fatty acid composition (gas chromatography) and lipid peroxidation (thiobarbituric acid‐reactive substances (TBARS)). A higher (p < 0.05) percentage of total sperm motility was observed in ALA groups 5 ng/ml (47.74 ± 07) and 10 ng/ml (44.90 ± 0.7) in comparison with control (34.53 ± 3.0), 3 ng/ml (34.40 ± 2.6) and 15 ng/ml (34.60 ± 2.9). Still, the 5 ng/ml ALA group presented a higher (p < 0.05) percentage of viable sperms (74.13 ± 0.8) and sperms with intact membrane (74.46 ± 09) than all other experimental groups. ALA concentration and lipid peroxidation in post‐thawed sperm was higher in all treated groups when compared to the control group. As such, the addition of 5 ng/ml of ALA to Tris extender improved quality of frozen–thawed bull spermatozoa.     

Concentrations of exchangeable bases and cation exchange capacity in soils of cropland, grazing and forest in the Bale Mountains, Ethiopia

Conversion of native forest ecosystem to cropland has considerably degraded the soil nutrient levels in the Bale Mountains, south-eastern highlands of Ethiopia. This study investigated the effects of land use change through conversion of native forest to cropland and/or grazing land on soil pH (H₂O), base cations (Ca²⁺, Mg²⁺, K⁺, Na⁺), CEC and percentage base saturation (PBS) in three adjacent land-use types: cropland, grazing land and native forest. A total of 108 soil samples (3 replications × 3 land-use types × 4 profiles × 3 soil depth layers, 0–0.2, 0.2–0.4 and 0.4–1.0 m) were collected for laboratory analyses. Results showed that soil pH, Na⁺ and K⁺, CEC, and PBS varied significantly with respect to land use and soil depth while Ca²⁺and Mg²⁺ varied with soil depth (ρ < 0.05). Conversion of native forest ecosystem to cropland during a 15-year period significantly increased soil pH and PBS while reducing Na⁺ and K⁺. The CEC in the cropland was reduced by 37.7% (2.6% per annum) compared to the native forest, which could be attributed to the decline in organic matter concentrations. If such rapid declines in soil nutrient concentrations continue unabated, the soils will reach at the point of no return within a few decades. Although the effect of grazing on most of the properties was found to be minimal, adapting the number of stock to the carrying capacity of the land and thereby enhancing the natural regeneration, combined with proper cropland management practices could help restoring soil nutrients for sustainable agricultural production and ecosystem functions.     

Contribution of participatory forest management towards conservation and rehabilitation of dry Afromontane forests and its implications for carbon management in the tropical Southeastern Highlands of Ethiopia

Participatory forest management (PFM) has been applied as an approach to create a framework for collaborative forest management between local communities and government forestry agencies. This study was designed to assess the contribution of PFM approach in improving forest status in the Southeastern Highlands of Ethiopia. Landsat satellite imageries of four years were used to evaluate the trends and rate of deforestation before and after PFM interventions. Socio-economic data were collected from sample household surveys, key participants, focus group discussions, and field observations. The results showed that there was high rate of deforestation before PFM intervention as forestland has decreased by 19% (2531 ha) between 1990 and 2000. However, after the PFM intervention (2000–2016), the forest cover has increased by 247 ha (2.2%). During this period, net 1016 ha of shrub-lands were converted into forestland owing to significant forest regeneration. In addition, most sampled households (94% and 96% from lower and upper altitudes, respectively) perceived that PFM had significantly contributed to improve forest regeneration in their locality. This study revealed that PFM can serve as a stepping stone for carbon financing mechanisms to reduce greenhouses emission and enhance carbon sinks via forest resources.     

Diagnostics of the peach root-knot nematode,Meloidogyne floridensis using multiplex real-time PCR

European Journal of Plant Pathology - The peach root-knot nematode, Meloidogyne floridensis is an emerging pest of peach and other crops that is currently known to occur only in California,...     

Effect of Semen Collection Methods on the Quality of Pre‐ and Post‐thawed Bali Cattle (Bos javanicus) Spermatozoa

This study was conducted to evaluate the response of Bali bulls (Bos javanicus) to different semen collection methods and their effects on fresh and post‐thawed semen quality. The collection methods employed were electro‐ejaculation (EE), transrectal massage (RM) and RM followed by EE (RM + EE). A total of 25 untrained Bali bulls (age between 2 and 4 years old) were subjected to the different semen collection methods. Fresh semen samples from all the 25 bulls were evaluated for volume, pH, general motility, live/dead ratio and abnormality using the conventional method. For fresh and frozen samples collected by EE and RM from 10 bulls, computer‐assisted semen analysis system was used for precise quantitative measurement of motility, velocity and forward progression. Accucell photometer was used to measure sperm concentration in all samples, regardless fresh and frozen. Semen samples were obtained 100% of the attempts using EE, 84% using RM and 96% using RM + EE. There were no differences among the collection methods for fresh semen quality characteristics, including motility, morphology and viability, but pH and volume were higher for EE than RM and RM + EE. Higher sperm concentration was observed in semen collected by RM than the other two methods. Different age groups (2–3 and >3–4 years old) of the bulls did not show significant differences in volume, pH, sperm concentration, percentages in motility, live/dead ratio and normal sperm morphology. The quality of semen for general and progressive motility, VAP, VSL and VCL and acrosomal integrity after thawing was higher for RM than EE. In conclusion, Bali bulls appeared to respond best to EE and the combination of RM + EE than RM, as a method of semen collection, with a shorter time of stimulation required. Differences in age of the Bali bulls did not affect the semen quality.     

Ovarian activity in beef and dairy cows with prolonged postpartum period and heifers that fail to conceive

The primary objectives of this study were to investigate incidence of abnormal ovarian cyclicity (AOC) and its type in dairy and beef cows with prolonged postpartum period (>90 days) and in heifers that fail to conceive. A total of 53 animals were included in the study: 17 Friesian crosses, 16 Braford crosses, eight Brangus crosses, and 12 local Kedah-Kelantan (KKX) crosses. These animals were initially checked for absence of pregnancy via palpation per rectum. Blood samples for progesterone analysis were obtained twice a week for 2 to 3 months following their spontaneous oestrous cycle, and all animals were rechecked for pregnancy at the end of the study. Progesterone analysis indicated that 33.9% of the total animals were having AOC: 18.9% with cessation of ovarian cyclicity, 9.4% with prolonged luteal phases (PLP), and 5.7% short luteal phases. The highest incidence was observed in Brangus crosses (62.5%), followed by Braford crosses (43.8%), and Friesian crosses (35.3%). In contrast, no AOC was observed in the local KKX breeds, and all of them were found to be pregnant at the end of the study. A significant difference (p < 0.05) in the incidence of AOC and its type was observed between Kedah-Kelantan crosses and the other breeds. Although not significant (p > 0.05), Friesian crosses showed a higher percentage incidence of AOC than beef cows (40% vs 36.4%), with major types being PLP (26.7%) in dairy and cessation of ovarian cycle (27.3%) in beef cows. Compared with beef heifers, beef cows showed a higher percentage of AOC (36.4% vs 28.6%) where again, cessation of cyclicity was the predominant abnormality. In conclusion, AOC reflected by abnormal endocrine pattern is a possible cause of reduction in fertility for dairy and beef cows beyond 90 days postpartum and heifers that fail to conceive.