Studies on fascioliasis in four selected sites in Ethiopia

The incidence of fascioliasis was studied in Asela, Awasa, Debre Zeit and Debre Berhan by using 153 experimental sheep divided up into 4 groups designated tracer sheep, Controls I, II and III. Fasciola hepatica was encountered in Debre Berhan, Asela and Awasa, but it was not detected at Debre Zeit. In all areas, it was most frequently recovered after heavy rains. Altitude, soil type, salt content and local crowding of animals in watering sites appear to have influenced the varying degrees of incidence and intensity of infection.     

Occurrence of aphid vector and genetic tolerance to infection by potyvirus in hot pepper

The productivity and marketable quality of hot pepper (Capsicum annuum var. annuum L.) are low in tropical regions mainly due to virus infections and lack of effective virus management strategies. The absence of effective virus management strategies could be attributed to lack of information on virus vectors and host resistance. Parental (P₁ and P₂) and progeny (F₁, B₁, B₂ and F₂) generations of five hot pepper crosses were grown in Ethiopia at three sites (Bako, Hawasa and Melkasa) to monitor number and species of potential aphid vectors, disease incidence levels with regards to natural infections by Potato virus Y (PVY) and Ethiopian pepper mottle virus (EPMV) complex, and to determine genetic tolerance of the crop to the viruses. Disease incidence was assessed before the flowering stage of the crop plants using visible disease symptoms due to infections by PVY and EPMV. The serological tests revealed presence of symptomless genotypes of the crop to the virus infections. Aphid species potentially transmitting the viruses, such as Acyrthosiphon pisum (Harris), Aphis fabae (Scopoli), and Myzus persicae (Sulzer), were identified from specimens caught by yellow water traps. The highest number of aphids from yellow water traps was recorded at a dense foliage growth stage of the crop at Melkasa. Highly significant variation was observed among generations of the five crosses in response to infections by PVY and EPMV complex. The most susceptible parents had the levels of disease incidences ranging from 80 to 90%, whereas their progenies had only below 30% incidence levels. The most tolerant parent remained symptomless to the natural infections of PVY- and EPMV-complex. Incidence levels in progenies of a cross from the most susceptible and tolerant parents remained below 20%. Based on serological test, the proportion of PVY-positive plants ranged from 0 to 75% and of EPMV-positive plants from 0 to 25%, with 0 to 17% co-infection by the two viruses. Availability of virus sources in the vicinity, efficiency of aphids in vectoring, weather conditions during the growth period, genetic tolerance and the growth stage of the crop affected natural infection by PVY- and EPMV-complex. Exploitation of the genetic potential of introduced elite genotypes and their progenies along with breeding elite local cultivars for resistance and excluding aphid vectors at young (seedling) stage of the crop plants could be helpful for minimizing losses in yield and quality of hot pepper due to infections by PVY- and EPMV-complex.     

Growth performances of Washera sheep under smallholder management systems in Yilmanadensa and Quarit districts,Ethiopia

A study was conducted to evaluate growth performances of Washera sheep under smallholder production systems in the Yilmanadensa and Quarit districts of the Amhara National Regional State, Ethiopia. Data were collected and analysed on the growth of 690 lambs owned by 110 households from October 2004 to September 2007. Weight (kilograms) of Washera lambs at birth, 1, 3, 6, 9 and 12 months of age was 2.69 ± 0.02, 7.10 ± 0.16, 12.42 ± 0.11, 16.12 ± 0.91, 20.05 ± 0.55 and 23.47 ± 0.68, respectively. Birth weight was significantly (P < 0.05) affected by district, year of birth, parity of the dam, birth type and sex of lamb and by the interaction effect of parity by birth type and parity by sex of lamb. Weaning weight was also affected by year of birth, type of birth and sex of lamb. Yearling weight was affected by only year of birth and sex of birth. The average daily weight gain (ADG; grams) from birth to 30 days, birth to 90 days, 90 to 180 days and birth to 1 year of age was 143.37 ± 13.46, 107.09 ± 2.67, 39.78 ± 9.73 and 60.13 ± 1.89, respectively. Growth rates from birth to 30 and 90 days of age were significantly (P < 0.05) affected by birth year, birth type and sex. ADG from birth to 1 year of age was affected by lamb sex and district. The indigenous Washera sheep had faster growth rate than those sheep breeds of Ethiopia extensively studied thus far. Integrated efforts combining improved nutrition, health and participatory community-based breeding would help the smallholder farmers to utilise and conserve this immense sheep genetic resource of Ethiopia.     

Effect of breed and other animal-related factors on conception rate to artificial insemination with frozen semen in mares in Ethiopia

Equine reproduction is unique by having long behavioral estrus and differences in time of breeding between breeds and individuals of mares. An experimental study was conducted at the Balderas Sport Horses and Recreational Center, Addis Ababa, Ethiopia, from January to June, 2018, to evaluate conception rate to frozen semen in local and exotic crossbreed mares. Mares were teased to characterize estrus behavior and examined by ultrasound in determining imminent ovulation. Inseminations were done post ovulation within an average of 6–9 h using frozen-thawed semen. The overall conception rate to frozen semen was 15/21 (71.43%) with 8/11 (72.73%) in crossbreed and 7/10 (70%) in local breed mares. Age and body condition score (BCS) of animals had no significant effect on conception rate to AI with frozen semen. A slightly higher conception rate was obtained when ovulation was from the right ovary than when ovulated from the left ovary. A higher conception rate was obtained when the diameter of the preovulatory follicle was ≤ 45 mm than above diameter. The conception rate increased significantly with increased number of services/conception with an overall mean ± (SEM) of 2.2 ± 0.2 services/conception. A more number of services/conception were required for local breed (2.7 ± 0.2) than crossbreed mares (1.8 ± 0.3) and again for lower body condition scores than higher condition scores of mares. In conclusion, the increased number of services improved the conception rate with significant difference between breed of mares, whereas good management of mares for improved body conditions could be required to decrease the number of services per conception.

     

The effect of body condition on ovarian activity of free ranging tropical jennies (Equus asinus)

Serial ultrasonography was performed on seven jennies to study the effect of seasonally fluctuating body condition on ovarian activity during the dry, short rainy and long rainy seasons. Kendall Tau correlations and differences of least square mean values were compared. A distinct seasonal pattern was observed both in body condition and ovarian activity. The mean (+/-SD) Body Condition Score (BCS) was lowest during the dry season 2.6 +/- 0.45 when compared with 3.5 +/- 0.52 and 3.9 +/- 0.58 during the short and long rainy seasons, respectively. The mean (+/-SD) number of total follicles was also proportionally low 7.3 +/- 1.6 during the dry season compared with 9.6 +/- 2.4 and 11.3 +/- 3.3 found during the short and the long rainy seasons, respectively. The BCS was positively correlated to the total number of follicles and the diameter of the largest follicle during all seasons. Periods of increasing BCS and transition between seasons with both increasing and decreasing body conditions were strongly correlated to the number and size of ovarian follicles. Seasonal fluctuation in the body condition was found to be the result of variation in feed resource and ovarian activity was also closely following this seasonal pattern. The improvement in body condition has generally, a positive impact on emergence of small growing follicles there by having influence on the total count of ovarian follicles.     

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.     

Breeding practices,growth, and carcass potential of fat-tailed Washera sheep breed in Ethiopia

On-farm survey of farmers' breeding practices, breeding objectives, and selection criteria and on-station feedlot performance evaluation of Washera sheep were undertaken in Ethiopia. The survey revealed that most (79.8%) of the farmers had no breeding ram. The mating system was predominantly uncontrolled. A majority (75.5%) of the sheep owners reported that they herded their sheep flock by mixing with other livestock species mainly with cattle. During grazing, 44.6% of the farmers mix their sheep flock with neighboring sheep flocks. The major sheep production objective was to generate income from the sale of live sheep. Fast growth, appearance, coat color, and pedigree performance were important ram selection criteria, respectively. Ability to breed at early age, pedigree information, mothering ability, and lambing interval were important selection criteria for ewe, respectively. The on-station performance study involved evaluation of feedlot gains and carcass production under five levels of feeding regimes (300, 400, 500, 600, and 700 g day⁻¹ of concentrate feed) for a period of 93 days. The results indicated that the feedlot growth and carcass performance of Washera sheep were very high, with average daily weight gains of up to 126 g and carcass weight of 16 kg, with the optimal level of supplementation for Washera sheep being at 500 g of concentrate per day for a period of 93 days.     

A psbA mutation in Kochia scoparia (L) Schrad from railroad rights-of-way with resistance to diuron, tebuthiuron and metribuzin

Kochia [Kochia scoparia (L) Schrad] has become resistant to many herbicides used in cropland and railroad rights-of-way in North Dakota and Minnesota. Kochia scoparia plants that had survived annual treatments with diuron and tebuthiuron were sampled along railroad rights-of-way in North Dakota and Minnesota. The samples were screened in the greenhouse for resistance to diuron, tebuthiuron, metribuzin and bromoxynil from 0.5x to 32x the recommended use rates. A resistant K scoparia accession (MN-3R) was confirmed with resistance up to 16-fold higher than recommended use rates for tebuthiuron and diuron and up to 4-fold higher for metribuzin. However, the resistant K scoparia accession was susceptible to bromoxynil even at 50% of the recommended use rate. The herbicide binding region of the psbA gene fragment of eight resistant (R) and seven susceptible (S) K scoparia accessions was PCR-amplified and sequenced for detection of mutations. The psbA gene of four R K scoparia accessions was mutated at residue 219 with substitution of isoleucine for valine (GenBank accession number AY251265). The seven S K scoparia accession sequences were wild-type at this residue (GenBank accession number AY251266). The other four R accessions sequences showed a previously known triazine R mutation with substitution of glycine for serine at residue 264. All 15 K scoparia accessions were wild-type at all other psbA residues within the region analyzed. Resistance to diuron, tebuthiuron and metribuzin among the railroad rights-of-way K scoparia is probably due to the mutation at residue 219 of the psbA gene in some plants, but due to the previously reported Ser(264)Gly substitution in other plants. Target-site resistance associated with a change of valine to isoleucine at residue 219 of the psbA target-site in weeds has previously been reported for Poa annua L selected in diuron-treated grass seed fields, and for Amaranthus powelli S Wats selected in linuron-treated carrot fields. This is the first report of the mutation in herbicide-resistant K scoparia.     

Application of ultrasonography in the study of the reproductive system of tropical jennies (shape Equus asinus)

The use of high-frequency (5 MHz) ultrasonography was studied in 11 jennies (7 non-pregnant and 4 pregnant) to characterize the reproductive organs and follicular activities at different stages of reproduction. The result showed close similarity with the mare. The visibility of endometrial folds increased towards ovulation. A positive correlation (p < 0.001; τ = 0.79) was found between the score of the folds and the size of the dominant follicle. The diameter of the uterus and the size of the dominant follicle were significantly correlated (p < 0.001; τ = 0.80). In pregnant jennies, an embryonic vesicle was detectable at 14 days. Follicular growth was characterized by more than one wave. The smallest ovarian follicle was 2 mm and the largest 40 mm. Depending on the reproductive stage, up to 13 follicles were detected per ovary. After monitoring 84 cycles, a mean (±SD) diameter of 34.4 ± 3.6 mm (27.5–40.2 mm) of the preovulatory follicle and 67.85% incidence of single ovulation were found. The mean (±SD) interovulatory interval was 25.7 ± 6 days. This study proved that high-frequency ultrasonography is highly effective in characterizing the reproductive organs and follicular activity of jennies and could be useful in the reproductive management of donkeys.     

Decomposition and substrate quality of leaf litters and fine roots from three exotic plantations and a native forest in the southwestern highlands of Ethiopia

Substrate quality and decomposition (measured as CO₂ release in laboratory microcosms) of fresh leaf litter and fine roots of Cupressus lusitanica, Pinus patula, Eucalyptus grandis and native forest trees were studied. Changes in litter chemistry in each forest stand were analysed by comparing fresh leaf litter (collected from trees) and decomposed litter from the forest floor. Elemental concentrations, proximate fractions including monomeric sugars, and cross polarisation magic-angle spinning (CPMAS) ¹³C NMR spectra were analysed in leaf litters, decomposed litter and fine roots. Leaf litters and fine roots varied in their initial substrate chemistry with Ca concentration in leaf litters being higher than that in fine roots. In each stand, fine roots had a higher acid unhydrolysable residue (AUR) (except for the Pinus stand), higher holocellulose concentration and lower concentration of water-soluble extractives (WSE) and dichloromethane extractives (NPE) than fresh leaf litter. Likewise, ¹³C NMR spectra of fine roots showed lower alkyl and carboxyl C, and higher phenolic (except P. patula), aromatic and O-alkyl C proportions than leaf litters. Compared with fresh leaf litter, decomposed litter had lower concentrations of potassium, holocellulose, WSE, NPE, arabinose and galactose, similar or higher concentrations of Mg, Ca, S and P, and higher concentrations of N and AUR. CPMAS ¹³C NMR spectra of decomposed litter showed a higher relative increase in signal intensity due to methoxyl C, aromatic C, phenolic C and carboxylic C compared with alkyl C. In a microcosm decomposition study, the proportion of initial C remaining in leaf litter and fine roots significantly fitted an exponential regression model. The decomposition constants (k) ranged between 0.0013 and 0.0030 d⁻¹ for leaf litters and 0.0010-0.0017 d⁻¹ for fine roots. In leaf litters there was a positive correlation between the k value and the initial Ca concentration, and in fine roots there was an analogous positive correlation with initial WSE. Leaf litters decomposed in the order Cupressus>native forest>Eucalyptus∼Pinus, and fine roots in the order Pinus>native forest>Cupressus∼Eucalyptus. In each stand the fine root decomposition was significantly lower than the leaf litter decomposition, except for the P. patula stand where the order was reversed.