| Author | Gebretsadik, Zelealem Tesfay |
| Call Number | AIT Diss. no.FB-13-01 |
| Subject(s) | Sheep breeds Ethiopia
Sheep Ethiopia
|
| Note | A dissertation submitted in partial fulfillment of the requirement for the degree of Doctor of Philosophy in Food Engineering and Bioprocess Technology, School of Environment, Resources and Development |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. FB-13-01 |
| Abstract | The farm animal genetic resource (livestock) in Ethiopia has great importance in the
livelihood of the small farm households. However, the farm genetic resources and their
production constraints in the country are not efficiently characterized and hence, created
difficulty for a better and efficient utilization of these resources. Therefore, knowing the
animal genetic resources, their importance and constraints vis-à-vis the production system,
agro ecology and genotype is inevitable. One of the farm animal genetic resources with
significant importance to small households in Ethiopia is sheep. This study focuses on the
identification of sheep breeds, their production systems, their values and ways of
improving their products in yield and quality, thereby improve the livelihood of small
households and microenterprises involved in sheep fattening and meat production. The
study focusses on sheep breeds of Northern Ethiopia, more specifically of Tigrai region.
Based on morphological characteristics and discriminant analysis, four breeds of sheep
have been identified. These are Begait, Abergelle, Ille and the Common Tigrai Highland
sheep. The discriminating phenotypes according to their strength of discrimination are face
profile (accounting for 83.48% of the difference), tail type (accounting for 17.95% the
difference) and compactness (accounting for 2.93% of the difference). Based on the
production system assessment, it was possible to identify the major factors affecting flock
structure, production constraints, major use of sheep and sheep market chain. The flock
structure seems to be affected by the demand, requirement of breeding female, feed
availability and the occurrence of disease and natural calamities. Farmers tend to keep
more female sheep for longer (culling age of 5.9 ± 0.4 and 1.9 ± 0.5 for females and males
respectively) for the reasons of feed shortage and requirement for breeding female. The
ratio of male to overall female is small (1:6) and hence rams has maximum contact time
with ewes that might contribute for inbreeding. The overall average age at puberty for
female is 9-14 months. However, the presence of very young lamb rams and uncontrolled
mating system led to early breeding of females which resulted in low conception rate, low
birth weight, poor survival rates and in extreme cases causing inbreeding. The market
structure for live animals in Tigrai region has four hierarchies with extremely poor
infrastructure further affecting the provision of quality meat to the end consumer. In this
survey was also noted that five critical control points such as choice of breed (especially
sire), age of animals, feed & feeding, animal diseases & pests and the market
infrastructures need to be given emphasis to ensure supply of live animal for better quality
meat and profitability of the producers. In the effort to improve growth performance and
meat quality of two sheep breeds (Abergell and Begait sheep). Thirty rams aged between
six and eight months (fifteen each) from two sheep breeds were kept under three diet
treatments containing two different ratios (3:2 and 1:1) of wheat bran and sesame seed
cake along with grazing. The animals were not fed with wheat bran and sesame seed cake
was kept as control. The total amount of supplement was 600 g per day. The animals were
left for grazing at the same time with the same types and amount of materials. The growth
performance, carcass characteristics, meat quality and fatty acid contents were assessed after two months of feeding trial. Abergelle breed has higher value for moisture (71.38%)
and ash (2.55%) contents and dressing percentage (49.13%) (p < 0.001). Begait breed had
higher values (p <0.01) for hot and cold carcass yield (12.43 kg and 12.24 kg respectively).
Over 51% dressing percentage was achieved in supplemented groups compared to 45% for
non-supplemented groups. Generally it was managed to attain a daily growth rate of 160-
180g and 173-175g for Abergelle and Begait breed respectively on grazing rams
supplemented with 600g of SSC and WB mixture. Water holding capacity and pH (after 24
h of stored meat; pH24) were found similar for both breeds [(15.64-15.76) and (5.6) for
water holding capacity and pH24 respectively] (p > 0.05). However, cooking loss and
tenderness showed significant difference (p < 0.01) between breeds. Begait breed had
lower values for cooking loss (24.68 Vs. 26.55). Long chain fatty acids such as Palmitic
(C16:0), Stearic (C18:0), Oleic (C18:1n-9) and Linoleic (C18:2n-6) have showed a
significant differences among the breeds (p < 0.01). Meat form Begait sheep had higher
concentration of C18:0 (18.18 Vs. 16.47) and C18:1n-9 (36.46 Vs. 35.52) while meat form
Abergelle sheep had higher values for C16:0 (25.02 Vs. 24.36) and C18:2n-6 (6.58 Vs.
6.30). Supplementation of wheat bran and sesame seed cake brought significant change on
concentration of Pentadecylic (C15:0) and Linoleic (C18:2n-6) only, with other fatty acid
concentrations showed no change (p >0.05). Based on the meat quality measurements and
the fatty acid profile, it was concluded that the meat from the two breeds (Abergelle and
Begait) had acceptable levels of fatty acids especially the Oleic and Linoleic; and had
optimum levels of cooking loss and WHC. |
| Year | 2013 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. FB-13-01 |
| Type | Dissertation |
| School | School of Environment, Resources, and Development (SERD) |
| Department | Department of Food, Agriculture and Natural Resources (Former title: Department of Food Agriculture, and BioResources (DFAB)) |
| Academic Program/FoS | Food Engineering and Bioprocess Technology (FB) |
| Chairperson(s) | Anal, Anil Kumar |
| Examination Committee(s) | Athapol Noomhorm;Rakshit, Sudip Kumar;Yakupitiyage, Amararatne |
| Scholarship Donor(s) | Ministry of Agriculture, Ethiopia |
| Degree | Thesis (Ph.D.) - Asian Institute of Technology, 2013 |
