Plant Diversity and Vegetation Structure in Encroached and Non-encroached Areas of Borana Rangelands： The Case of Hallona and Medhacho Pastoralist Associations

The Borana rangelands are important areas of cattle production in Ethiopia. However, these rangelands are threatened by the increasing changes in the natural vegetation from grass and forbs dominated into unpalatable bushy woody vegetation resulting in the loss of some of the highly desirable grass species. This study was conducted to assess the impacts of bush encroachment on the biodiversity, structure and cover of the native vegetation in bush encroached and non-encroached sites. Vegetation data were collected from both sites by laying quadrate plots along transects using a systematic sampling method. According to the results, higher number of species was recorded in the non-encroached sites than that in the encroached sites. The diversity indices for the non-encroached and the encroached sites were 3.16 and 2.67, respectively. The abundance and cover analysis indicated that there was high density and cover of herbaceous species in the non-encroached site. There was a significantly higher density of woody species cover in the encroached site. Generally, the bush encroachment in the Borana rangelands has hampered the diversity of the native vegetation, particularly the grasses and forbs and reduced the ground cover, exposing large parts of the rangelands for soil erosion and other degradation process.     

Floristic diversity, regeneration status, and vegetation structure of woodlands in Metema Area, Amhara National Regional State, Northwestern Ethiopia

We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state, Ethiopia Our objective was to describe plant species composition, diversity, regeneration status, and population structure by a selective approach with asystematic sampling design. A total of 74 quadrats (each for 25 m × 25 m,spaced at intervals of 150 200 m) were sampled along established transect lines following the homogeneity of the vegetation. Vegetation data including cover-abundance, height, diameter at breast height (DBH), and numbers of seedlings and saplings of woody species were analyzed using Excel spreadsheet, Shannon Weiner diversity index, and PAST version 1.62. A total of 87 vascular plant species of 74 genera and 36 families were recorded. The dominant family was Fabaceae represented by 16(18.39 %) species of 13 genera. Shannon Weiner diversity and evenness were 3.67 and 0.82, respectively, which showed that the area was endowed with rich floral diversity evenly distributed. The vegetation structure, as quantified by cumulative diameter class frequency distribution,plotted as an interrupted inverted-J-shape pattern with a sharp decreasein the 2nd diameter class. This indicated poor vegetation structure. The diameter classes frequency distributions of selected species plotted infour general patterns i.e., interrupted Inverted-J-shape, J-shape,Bell-shape and Irregular-shape. In conclusion, although the area showedhigh floral diversity and evenness, woody species including Sterculea setigera, Boswellia papyrifera, and Pterocarpus lucens showed lowest recruitment of seedlings and saplings.     

Plant community and ecological analysis of woodland vegetation in Metema Area, Amhara National Regional State, Northwestern Ethiopia

We studied woodland vegetation in broad-leaved deciduous woodlands of Metema in northwestern Amhara regional state,Ethiopia to determine plant community types and species distribution patterns and their relationships with environmental variables,including altitude,pH,cation exchange capacity,electrical conductivity(EC),and moisture.We used a selective approach with a systematic sampling design.A total of 74 quadrats,each 25m × 25m at intervals of 150 200 m were sampled along the established transect lines.For herbaceous vegetation and soil data collection,five subquadrats each 1m × 1m were established at the four corners and the center of each quadrat.Three community types were identified using TWINSPAN analysis.All three community types showed high diversity(Shannon-Weiner index),the highest in community type II at 3.55.The highest similarity coefficient was 0.49(49%) between community types II and III,reflecting 0.51(51%) dissimilarity in their species richness.The canonical correspondence ordination diagram revealed that the distribution pattern of community type I was explained by moisture while that of community types III and II was explained by EC and altitude and moisture,respectively.Altitude was the most statistically significant environmental variable,followed by moisture and EC in determining the total variation in species composition and distribution patterns while pH and cation exchange capacity were non significant.In conclusion,we recommend that any intervention should take into account these three discrete community types and their environmental settings to make the intervention more successful.     

Modeling the relationships between quality and biochemical composition of fatty liver in mule ducks

The fatty liver of mule ducks (i.e., French "foie gras") is the most valuable product in duck production systems. Its quality is measured by the technological yield, which is the opposite of the fat loss during cooking. The purpose of this study was to determine whether biochemical measures of fatty liver could be used to accurately predict the technological yield (TY). Ninety-one male mule ducks were bred, overfed, and slaughtered under commercial conditions. Fatty liver weight (FLW) and biochemical variables, such as DM, lipid (LIP), and protein content (PROT), were collected. To evaluate evidence for nonlinear fat loss during cooking, we compared regression models describing linear and nonlinear relations between biochemical measures and TY. We detected significantly greater (P = 0.02) linear relation between DM and TY. Our results indicate that LIP and PROT follow a different pattern (linear) than DM and showed that LIP and PROT are nonexclusive contributing factors to TY. Other components, such as carbohydrates, other than those measured in this study, could contribute to DM. Stepwise regression for TY was performed. The traditional model with FLW was tested. The results showed that the weight of the liver is of limited value in the determination of fat loss during cooking (R(2) = 0.14). The most accurate TY prediction equation included DM (in linear and quadratic terms), FLW, and PROT (R(2) = 0.43). Biochemical measures in the fatty liver were more accurate predictors of TY than FLW. The model is useful in commercial conditions because DM, PROT, and FLW are noninvasive measures.     

Effect of postweaning feeding on the performance and energy balance of female rabbits at different physiological states

The feeding of a high-fiber and low-energy diet to young rabbit does from weaning to the first kindling was used to modify their body reserves, stimulate their energy intake, and reduce the energy deficit during the first lactation. Rabbits (53 per group) were given ad libitum access to either a control or high-fiber diet (CP, 17.6 vs 15.8% of DM; crude fiber, 15.5 vs 19.9% of DM; digestible energy, 2,565 vs 2,261 kcal/kg of DM, respectively) from weaning to their first kindling. During lactation, both groups received the same diet, which contained 19.3% CP, 16.5% crude fiber, and 2,634 kcal/kg digestible energy (dry matter basis). Four comparative slaughters were performed to estimate the chemical and energy balance of rabbit does at different physiological states: at the beginning of the trial (12 rabbits, 45 d of age), at mating (10 rabbits per group, 136 d), at kindling (10 rabbits per group, 167 d), and at the end of lactation (12 and 11 rabbits for the control and the high-fiber group, 197 d). Large changes in body weight and composition were observed between slaughters. From 45 d to mating, doe body fat and energy increased 7.93 and 4.64 times the initial content, respectively. During pregnancy, body protein concentration decreased from 203 to 186 g/kg. At the end of lactation, body fat and energy concentration were reduced to values close to those measured at 45 d of age. Dietary treatment affected body chemical and energy balance during pregnancy and lactation but not reproductive and lactational performance. The high-fiber diet stimulated feed intake from weaning to the first kindling but not dietary energy intake. During lactation, the rabbits fed the high-fiber diet ate 10 kcal x d(-1) x kg live weight(-.75) more and lost less body fat (-405 vs -504 g) and body energy (-3,628 vs -4,294 kcal) than the does fed the control diet (P < .001). In the same period, all does showed water and protein retention (185 and 45 g, on average) regardless of dietary treatment. In conclusion, feeding young does a high-fiber diet until their first kindling reduced the chemical and energy body deficit at the end of the first lactation.     

Changes of Sorghum bicolor landrace diversity and farmers’ selection criteria over space and time,Ethiopia

Temporal and spatial changes in sorghum landrace diversity and distribution, field sizes, and farmers’ selection criteria were studied in five agricultural landscapes in North Shewa and South Wollo, Ethiopia. The study was undertaken during 2000/2001 and 2011/2012 cropping seasons in order to ascertain the stability of a range of factors that support the maintenance of sorghum landrace diversity. The same farmers were interviewed and the same sorghum fields were surveyed during both cropping seasons to determine the changes over the 11-year period. Farmers’ selection criteria increased significantly in all agricultural landscapes [Bati (P < 0.0001); Borkena (P < 0.0015); Epheson (P < 0.002); Hayk (P < 0.022); and Merewa Adere (P < 0.05)]. In Bati (P < 0.0081) and Merewa Adere (P < 0.0087), fields planted to sorghum landraces have increased significantly. Changes in field sizes in Epheson (P < 0.36) and Hayk (P < 0.237) did not show significant differences. The field sizes in Borkena (P < 0.0001) have decreased significantly due to population growth, land distribution policy, and seasonal variations followed by inter-and intra-species crop diversification. Sorghum landrace richness has increased significantly in Bati (P < 0.0001) and Hayk (P < 0.0001), marginally increased in Merewa Adere (P < 0.08). No significant changes have been observed in sorghum landrace richness in Borkena (P < 0.344) and Epheson (P < 0.24). In 2011/2012, 24 “generalist” sorghum landraces (grown widely across three or more agricultural landscapes), and 53 “specialist” sorghum landraces (restricted to certain microhabitats in one or two agricultural landscapes) were found. Landrace dynamics in response to farmers’ selection criteria and environmental variations are explained.     

Application of computed tomography to assess the effect of egg yolk ratio on body composition in chickens of different genotype and gender at hatch and during the rearing period

1. Computed tomography was used for the in vivo determination of yolk ratio in 7000 domestic hen eggs, originated from two markedly different genotypes, in order to examine the effect of egg yolk ratio, gender and genotype on the development of hatched chicks.

2. Eggs with extremely low, average and extremely high yolk ratio were chosen for further investigation (n = 350 in each group in both genotypes). After incubating the selected eggs, hatched birds were reared and slaughtered at 11 weeks of age.

3. The yolk ratio of eggs significantly affected the body composition of the chickens at hatching and during rearing to 8–9 weeks of age.

4. Chickens of a genotype selected partly for weight gain had significantly higher live weight from hatching to the end of the rearing period and had better slaughter characteristics than those of the dual purpose TETRA-H genotype.

5. At hatching, only the dry matter content of the body was affected by the gender of the birds. The effect of gender on the live weight and body composition of chickens was evident from the 5th week of age to the time of slaughter.

6. It was concluded that eggs with a low yolk ratio were most beneficial for broiler production, because chickens hatched from these eggs had the highest slaughter weight and muscle index and the lowest fat index for their body mass.