Livestock Research for Rural Development 21 (8) 2009 | Guide for preparation of papers | LRRD News | Citation of this paper |
Village chickens were said elsewhere to be an interesting tool to respond rapidly to rural poverty gaps but clear information was lacking in Ethiopia. The aim of this article was to gather, analyze and share the information generated so far at on-farm and on-station on indigenous chickens of Ethiopia. The information was collected on the morphologic and genetic diversity, the physical environment they live in and management systems employed, and on their population and distribution. Information also collected on their reproduction, production and health performance at on-farm and on-station levels and their economic benefits to the farmer. The challenges and limitations that faced them and ways foreword during the long walk to food security indicated. Indigenous chickens constituted by far the largest proportion of the poultry population in Ethiopia. They were distributed in different agro-ecologies and regional states where they depend primarily on what nature offers to sustain their life. The indigenous chickens represented a pool of heterogeneous and unimproved individuals that largely differ in morphology and genetic characteristics, production, health and reproductive performance on-farm as well as on-station. They had a lot of conserved traits that fit to cultural, socio-economical and environmental conditions of the area though not fully exploited. They granted their owners with economic and nutritional benefits with no or little input supply in the village scavenging system. So far both on-station and on-farm environment was not safe for them. Most of their problems under on-station confinement were linked to adaptation and health problems whereas their problems under scavenging system were linked to disease, nutritional and management errors. They were poorly understood and included in rural agricultural extension and development strategies. The available information and knowledge on flock structure and dynamics in the field was inadequate. Similarly, their genetic makeup and gene flow in the population, level of nutritional demand, their production performance under different management regimes, and resistance to disease and environmental stresses were poorly understood.
Keywords: Ethiopia, genetic resources, indigenous chickens, rural development, scavengabating system
Alarming poverty has been reported in Ethiopia with food and financial crisis (World Bank 1990). Poultry is an interesting tool to respond rapidly to poverty gaps if included in rural development strategies. It has fast generation interval and high reproductive rate. It is prolific, easy to rear and their output can be generally expanded more rapidly and easily than that of other livestock. According to Alemu and Tadelle (1997) 3 different scales of poultry productions are available in Ethiopia: large, small-scale commercial and scavenging. The 3 production systems have their own specific chicken breeds, inputs and production properties. Each can sustainably co-exist and contribute to solve the socio-economic problems of different target societies.
The commercial poultry sector is distributed in a limited urban and pri-urban location in Ethiopia, as it demands electricity, infrastructure and investment for intensification. It is found at an infant stage. It is constrained by high cost of input supplies such as day-old exotic chicks and feed. On the other hand, the scavenging production system is widespread in the country. The system constitutes mostly the indigenous chickens that have many advantages. The system and the chickens are cheaper and well established in the village of the country even where resource is poor. According to Horst (1989) they are also well adapted to the local environmental conditions (hot, humid, dry and rainy weather, feed and disease challenges). They have deep-rooted impact in the socio-cultural and economic profile of the rural community. However, in research, extension and development agenda the village indigenous chickens are poorly considered. Indigenous chickens and their role to curb socio-economical gaps are almost neglected in Ethiopia. Thus, the scavenging system and the indigenous chickens in the system is constrained by inadequate information at all stages of research, extension and development. The existing scattered inadequate efforts of research lack depth, coordination, evaluation, compilation and documentation of the scantly generated information. Research work is utterly wasted unless it is brought to public notice in some form.
Therefore, the aim of this study was to gather, analyze, summarize and share the available information on indigenous chicken genetic resources of Ethiopia for the future improvement outlooks. This work can form a good basis for further research, extension, development and genetic improvement and/or conservation.
The indigenous chickens are predominantly kept in traditional family-based free-range scavenging system (Alemu and Tadelle 1997). The feed resource base for the chickens is scavenging. It consists of household wastes, anything edible found in the immediate environment and small amounts of grain supplements provided by the farmers. Therefore, the scavenging feed resource is not constant. Thus, the birds are left to depend primarily on what nature offers. According to Kabatange and Katule (1989) feed supplies from home and the environment varies with farming activities such as land preparation, sowing, harvesting, grain availability in the household, season of the year and the life cycle of insects and other invertebrates. The system is characterized by critical protein deficit during dry season, critical energy deficit during rainy season and 60% mortality of immature chicks before weaning age (8 weeks) with unsuccessful brooding (Alemu and Tadelle 1997). In this line, supplementing 3 different feeding regimes have improved egg production of indigenous chickens under scavenging system. 15 g maize/bird/day +15 g Noug cake/day increases hen-day egg production by 30%, 30 g maize alone by 28% and 30 g Noug cake by 20% (Tadelle 1996). The innovated hay box chick brooder decreases mortality of baby chicks from 60% to 20-30% under on-farm conditions (Solomon 1999; Negussie et al 2003).
In general, the system is characterized by low stocking density, scarce nutrition, devastating seasonal mortalities, predators and other factors such as variable climatic factors such as variable air temperature, moisture, air circulation and dependency on sun light.
Ethiopia has huge number of indigenous chickens distributed in different agro-ecologies and regional states. Indigenous chickens that live in different geographical regional areas of the country have different names. The chickens are named after the names of the area of origin. For instance, Tilili, Horro, Tepi, Konso and Jarso are areas located in the northwest, west, southwest, south and east of the country, respectively. The chickens distributed in these areas are named after the names of the areas. Chicken population distribution varies with regional states in that higher in Oromia followed by Amahara Regional State. Harari Regional State has lower chicken population. The chickens are distributed in various ecologies including the pastoral areas such as Afar and Somali Regional State and big cities like Addis Ababa as indicated in the next Table.
Table 1. Regional and national chicken population ('000) distribution in Ethiopia |
||||
Region |
1987 |
2000£ |
2001/2002* |
2003/2004* |
Tigray |
|
|
4,049.48 |
3,725.11 |
Afar |
|
|
50.59 |
49.29 |
Amhara |
|
|
13,139.59 |
11,243.77 |
Oromia |
|
|
14,366.41 |
12,761.34 |
Somali |
|
|
125.20 |
173.19 |
Benishangul Gumuz |
|
|
905.26 |
785.36 |
Southern nations |
|
|
7,936.25 |
6,779.90 |
Gambella |
|
|
220.43 |
NA |
Hareri |
|
|
28.94 |
31.59 |
Addis Ababa |
|
|
66.33 |
62.36 |
Dire Dawa |
|
|
41.17 |
44.48 |
Country total |
58,000 |
65,000 |
40,929.65 |
35,656.39 |
Source: Alamargot 1987; £ FAO 2000; *CSA 2001-2004. NA: data not available |
Widely varying figures are reported on the total poultry population of Ethiopia across years as indicated in Table 1. This year-to-year chicken population variation may be due to lack of correct national census and documentation or due to population reduction by natural calamities that vary from year-to-year.
Density of chicken distribution varies with altitude with higher concentration in mid-altitude > highland > lowland. Indigenous chickens shares about 99% of Ethiopian 58 million poultry population (Alamargot 1987). Rural farmers keep more than 95% of this population and the flocks are small in number. An average of 7-10 mature birds are kept by a household consisting of 2-6 adult hens, 1-3 male birds and a number of growers of various ages (Tadelle 1996; Tadelle 2003). The AACMC (1984) reported an average of six native birds per household.
The chickens that inhabit the highland vary from the lowland in terms of body size, color and other morphologies. Such variation also exists within specific chicken population dwelling in a particular geographical area (Tadelle 1996). Chicken morphology is linked to the socio-cultural and religious sacrifices. Red and white cock is sacrificed for good rain and harvest, red and black spotted color (giracha) cock for New Year celebration, white and black spotted (gebsima) cock to prevent evil and calamities and red pullet for dead ancestors (animism) (Tadelle and Ogle 2001). The morphological characteristics of some Ethiopian indigenous chickens are indicated in Table 2.
Table 2. Morphological characteristics of three indigenous chicken ecotypes of Ethiopia |
|||||
Morphological Traits |
Horro (N=257) |
Tepi (N=105) |
Jarso (N=219) |
Total (N=581) |
|
Plumage color |
Black |
13.2% |
16.2% |
13.7% |
13.9% |
White |
21.8% |
11.4% |
18.7% |
18.8% |
|
Reddish gray (gebsima) |
8.6% |
10.5% |
9.6% |
9.3% |
|
Gray (kokima) |
11.3% |
29.5% |
21.0% |
18.2% |
|
Red |
19.5% |
29.9% |
21.5% |
20.8% |
|
Reddish gray (key dama) |
25.7% |
9.5% |
15.5% |
18.9% |
|
Naked neck |
0.04% |
- |
- |
|
|
Eye color |
Black |
100% |
100% |
100% |
100% |
Ear lobe color |
Black |
0.4% |
1.0% |
- |
- |
Red |
19.1% |
17.1% |
8.2% |
18.6% |
|
White |
54.5% |
57.1% |
86.3% |
67.0% |
|
Red and white (Silver) |
25.7% |
24.8% |
5.5% |
17.9% |
|
Other |
0.4% |
- |
- |
- |
|
Comb Pattern |
Double |
75.5% |
45.7% |
44.3% |
58.3% |
Single |
24.5% |
54.3% |
55.7% |
41.7% |
|
Comb color |
Black |
1.6% |
8.6% |
4.6% |
4.00% |
White |
1.6% |
1.0% |
13.7% |
6.00% |
|
Red |
52.1% |
34.3% |
15.1% |
34.9% |
|
Pale/roz |
44.7% |
56.2% |
66.7% |
55.1% |
|
Skin Color |
White |
20.6% |
16.2% |
12.3% |
16.7% |
Red |
79.0% |
83.8% |
87.7% |
83.1% |
|
Yellow |
0.4% |
- |
- |
- |
|
Body Size |
Small/dwarf |
16.0% |
9.5% |
31.1% |
20.5% |
Medium |
27.6% |
43.8% |
34.2% |
33.0% |
|
Large |
56.4% |
46.7% |
34.7% |
46.5% |
|
Source: Reta 2006 |
There is morphological diversity within and between the indigenous chicken ecotypes. Their plumage color is quite variable even within ecotype (pure black, white, silver white, gray, red and various combinations of several colors). Some chickens are dwarf/small, medium or heavy in body size. The dwarf chicks are mainly dominated in Jarso ecotypes (31.1%) that dwell in eastern part of Ethiopia and the heavy ones in Horro ecotypes (56.4%) originated from western Ethiopia. In Horro ecotypes, few chickens with naked neck and feathered shank are observed.
Chicken genetic variation both variations within and between breeds/ecotypes are crucial to meet human needs as it gives room and opportunity for selection or crossing. However, the volume of work pertaining to the genetic constitution of the indigenous chickens of Ethiopia is very small. Recently, genetic structure particularly the gene diversity and genetic distance of five indigenous chickens measured and compared using 10 micro-satellite markers by Tadelle (2003) using Fayoumi as a reference.
Table 3. Comparison of genetic distance between and genetic diversity within chicken ecotypes |
||||||
Chicken ecotypes |
Pair-wise genetic distance comparison between ecotypes |
Genetic diversity within ecotypesm % |
||||
Tilili |
Horro |
Chefe |
Jarso |
Tepi |
||
Tilili |
|
|
|
|
|
63 |
Horro |
0.05 |
|
|
|
|
57 |
Chefe |
0.10 |
0.09 |
|
|
|
63 |
Jarso |
0.10 |
0.11 |
0.08 |
|
|
55 |
Tepi |
0.09 |
0.09 |
0.19 |
0.19 |
|
61 |
Fayoumi (reference) |
0.25 |
0.25 |
0.34 |
0.35 |
0.31 |
60 |
Source: Tadelle 2003 |
Fayoumi chickens have the largest genetic distance to all indigenous chicken ecotypes. Jarso (0.35) and chefe (0.34) are the most distant ecotypes from the Fayoumi breed but Tilili (0.25) has the smallest. Genetic distance between Tepi and Chefe, Tepi and Jarso, Tilili and Jarso and Horro and Jarso is relatively far. But Tilili and Horro ecotype have the smallest genetic distance (related). Thus, moderate genetic distance between ecotypes is observed that indicates the possibility for genetic uniqueness and also simultaneously the sharing of genetic materials between ecotypes being out bred populations.
Genetic diversity within ecotype varies from ecotype to ecotype. It indicates limited interbreeding between the ecotypes due to their geographical separation or preferential mate selection and at the same time indicates the existence of genotypes within each ecotype. Significant differences are observed only between Tilili and Jarso and Chefe and Jarso respectively. Tadelle (2003) reported high genetic variation within ecotype and moderate genetic divergence (distance) between ecotypes, high microsatellite polymorphism, large number of alleles, high heterozygosity values for the six chicken ecotypes. This offers a basic step towards rational decision-making on the modalities of selective breeding without compromising the existence of each unique genetic resource. However, these preliminary results should be interpreted with caution because the number of birds, the number of loci as well as the manual scoring of microsatellites was potential sources of errors. Further studies using more birds per population and more microsatellite markers especially those recommended by FAO are necessary to validate the current findings.
Age at sexual maturity in chickens is 21 weeks of age and generation interval is about one year. The female chicken can produce one fertile egg per day with few non-production days per year. Embryonic development begins outside of and unattached to the dam's body. It allows continuing ovulation during the incubation period which lasts only three weeks before hatching. Exploitation of chicken reproductive biology via selection and crossbreeding techniques superimposed with its fast generation interval and high reproductive rate have transformed poultry into industry. It may be termed as a "living machine or factory".
The reproductive biology of indigenous chickens is less exploited but still has important qualities. According to Horst (1990) they are ideal mothers, good setters, hatch their own eggs, excellent foragers and vigor. They are aggressive, hardy and possess some degree of natural immunity against some diseases. These factors are important ideal requirements for replication and sustaining their generation in scavenging nature. On average, adult cock of Ethiopian indigenous chickens weighs about 2.1 Kg versus 1.4 Kg adult hens. Pullets reach sexual maturity at 21 weeks of age and start laying at the age of 5-6 months, with 2-3 laying cycles per year, producing 10-20 eggs in each cycle. About 13 eggs set for hatching and about 9 chicks finally hatch. The inter-clutch interval ranges from 2-3.5 months. Hatch to weaning period is an average of 2.8 months, with about 4-5 chickens in number. This implies a survival rate of 40-50% of the offspring hatched up to weaning (~60% die). Thus, most hens in the country wean 4-5 chicks. The reproductive cycle consists of a 10-20 day laying phase, a 21day incubation phase and finally a 56day brooding phase. The reproductive characteristics under on-farm scavenging and on-station confined conditions are summarized as follow.
Table 4. Reproductive performance of indigenous chickens of Ethiopia under scavenging system and on-station |
||
Reproductive characteristics |
Performance of indigenous chickens |
|
Percentage |
Time covered |
|
Length of laying phase |
|
10 -20 days |
Incubation period |
|
21 days |
Clutches /hen per year |
|
2-3 times |
Inter-clutch interval (Clutch length) |
|
60-105 days |
Eggs laid/hen/ clutch at on farm |
|
10 -20 eggs |
Eggs laid/bird/year on farm |
|
30-60 eggs |
Eggs laid/bird/year on station |
|
54-107 eggs |
Hen-day production on farm |
36% |
|
No. of eggs set for hatching on farm |
|
13.31-13.69 eggs |
No. of chickens hatched/set eggs |
|
9.09-9.51 chick |
Fertility of eggs collected from market |
36.2% |
|
Fertility at research station (on station) |
53-76% |
|
Hatchability of eggs set from market |
23.7% |
|
Hatchability of fertile eggs from market |
62.3% |
|
Hatchability of eggs set at on station |
39-52.5% |
|
Brooding period |
|
56 days |
No. of chicks weaned (Survival rate at 8th wk) |
|
4-5 chicks |
Age at sexual maturity |
|
21 weeks |
Age at first egg |
|
153-230 days |
Weight at first egg |
|
1-1.47 Kg |
Generation interval |
|
365 days (1yr) |
Source: AACMC 1984; Teketel 1986; Tadelle 1996; Mebratu 1997; NPPAR 2002; Tadelle 2003 |
The indigenous chickens are studied so far in two approaches as criteria for their differentiation and identification. 1) Based on their ecological/climatic region, thus the chickens are named after their area of geographical origin. 2) Based on morphologic characteristics for identification specially feather type and color. The performance in feed intake, feed conversion, body weight, egg parameters and health performance for chickens studied in the two approaches under on-farm scavenging and on-station confined conditions are summarized in the next presentations.
Table 5. On-station performance in feed intake, feed conversion ratio and body weight at different age levels among indigenous chickens of various regions (ecotypes) |
||||||||||
Age |
Performance |
Tilili |
Horro |
Chefe |
Jarso |
Tepi |
Dedo |
Sombo |
Gambella |
Mean |
0-6 weeks |
FI /bird, g |
637 |
878 |
670 |
437 |
570 |
NA |
NA |
NA |
638 |
FI /bird/day, g |
15.2 |
20.9 |
15.9 |
10.4 |
13.6 |
NA |
NA |
NA |
15.2 |
|
FCR |
4.9 |
8.3 |
4.5 |
5.2 |
6.4 |
NA |
NA |
NA |
5.9 |
|
8-12 weeks |
FI /bird, g |
1784 |
1393 |
173 |
1511 |
1399 |
NA |
NA |
NA |
1632 |
FI /bird/day, g |
42 |
33.2 |
41.4 |
35.9 |
33.3 |
NA |
NA |
NA |
38.9 |
|
FCR |
4.9 |
5 |
5.3 |
5.5 |
5.5 |
NA |
NA |
NA |
5.4 |
|
0-12 weeks |
FI /bird, g |
2360 |
2023 |
2409 |
1926 |
2038 |
NA |
NA |
NA |
2216 |
FI /bird/day, g) |
28.1 |
24.1 |
28.7 |
22.9 |
24.3 |
NA |
NA |
NA |
25.6 |
|
FCR |
5.0 |
5.7 |
5.2 |
5.6 |
5.7 |
NA |
NA |
NA |
5.6 |
|
Day-old |
Live weight, g |
30.7 |
28.7 |
32.4 |
25.8 |
26.0 |
NA |
NA |
NA |
NA |
6 weeks |
Live weight, g |
159.5 |
132 |
180 |
108 |
113 |
NA |
NA |
NA |
NA |
2 months |
Live weight, g |
285 |
267 |
281 |
15.9 |
185 |
166 |
132.2 |
136 |
NA |
4-5 months |
Live weight, g |
783 |
689 |
772 |
661 |
660 |
NA |
NA |
NA |
NA |
6 months |
Live weight, g |
NA |
NA |
NA |
NA |
1035 |
1253 |
1176 |
1234 |
NA |
Source: Brannag and Pearson 1990; Abebe 1992; Tadelle 1996; NPRAR 2002; Tadelle 2003; NA: data not available; FI: Feed intake; FCR: Feed conversion ratio |
The total and daily feed intake varies among the chickens in the order of Horro > Chefe > Tilili > Tepi >Jarso. In feed conversion ratio the order is Horro >Tepi > Jarso > Chefe >Tilili. The Tilili and Chefe ecotypes have feed conversion ratio below the mean for the indigenous chickens whereas the rest ecotypes have above the mean. The body weight gain per day varies in the order of Chefe > Tilili > Horro > Tepi > Jarso ecotypes. The Chefe and Tilili ecotypes have higher live body weight at day-old, 6 weeks, 2 months and 4.5 months of life. Tadelle (2003) reported a 212 g gain at 8 week of age under confined management, but with high coefficient of variation within ecotypes as high as 35-36%. In general, a given ecotype seems superior in a given production trait while at the same time inferior in other traits. For example, Tepi and Jarso seem better in feed intake and conversion ratio while Chefe and Tilili seem better in body gain and live weight. Horro has moderate feed intake, conversion efficiency, body gain and live weight. Thus, this variation is an opportunity for improvement to combine such traits via cross breeding or selection.
Under scavenging condition indigenous male chicks reach 1.5 kg live weight at 6 months while females about 30% less in Ethiopia (AACMC 1984). Teketel (1986) reported a 351 g body weight gain at 12 weeks of age for southern Ethiopian chicken ecotypes while Tadelle and Ogle (2001) reported 157 g body weight gain at 8 weeks of age in central Ethiopia.
The on-station performance of indigenous chickens is characterized based on chicken morphology (plumage color) as criteria for identification as summarized in the next Table.
Table 6. On-station body weight (g) performance of indigenous chickens with different morphologies |
||||||||
Age |
Station |
Red (Kei) |
Black (Tikur) |
Silver (Kokima) |
Wessera |
Gray (Gebsima) |
White (Netchi) |
Naked neck (Melata) |
Day-old |
Haromaya |
27 |
27 |
27 |
26 |
26 |
NA |
NA |
Hawassa |
32 |
32 |
NA |
NA |
31 |
32 |
35 |
|
8 weeks |
Haromaya |
237 |
240 |
256 |
225 |
228 |
NA |
NA |
Hawassa |
209 |
199 |
NA |
NA |
200 |
223 |
242 |
|
24 weeks |
Haromaya |
1003 |
775 |
850 |
1013 |
968 |
NA |
NA |
Hawassa |
1360 |
1350 |
NA |
NA |
1300 |
1420 |
1480 |
|
Source: Teketel 1986; Abebe 1992. NA: data not available |
According to chicken morphology the naked neck chickens have heavier weight followed by white, red and black colored chickens.
Eggs of indigenous chickens are preferred to exotic chickens because of their perceived pigmentation (egg color), organoleptic qualities (taste and flavor) and suitability for special dishes (Horst 1990).
Table 7. Egg parameters of indigenous chicken ecotypes of Ethiopia originated from various regions |
|||||||||||||
|
Tilili |
Horro |
Chefe |
Jarso |
Tepi |
Dedo |
Sombo |
Gambella |
Sodo |
Alemaya |
Arsi |
South |
National mean |
Egg weight, g |
NA |
39.7 |
NA |
37.2 |
39.2 |
45.3 |
42.3 |
44.3 |
NA |
NA |
38 |
42 |
39-42 |
% egg day |
NA |
NA |
NA |
NA |
0.26 |
0.3 |
0.23 |
0.2 |
NA |
NA |
NA |
NA |
NA |
Egg mass /hen/yr, kg |
NA |
NA |
NA |
NA |
3.92 |
5.14 |
3.56 |
3.29 |
NA |
NA |
NA |
NA |
NA |
Shell breakage strength, N |
NA |
0.53 |
NA |
0.64 |
0.57 |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
NA |
On-farm egg/hen/yr |
47 |
44 |
46 |
47 |
46 |
NA |
NA |
NA |
NA |
40 |
34 |
NA |
40-45 |
On-station egg/hen/yr |
NA |
NA |
NA |
NA |
94 |
107 |
84 |
78 |
84 |
99 |
NA |
NA |
85-95 |
Source: Bigbee 1965; Kidane 1980; AACMC 1984; Teketel 1986; Brannang and Pearson 1990; Abebe 1992; Tadelle 1996; NPPAR 2002; Tadelle 2003 and Reta unpublished data. NA: data not available |
There is variation in egg parameters among the indigenous chickens. The egg weight of chickens vary in the order of Dedo and Gambella > Sombo and South > the rest ecotypes. The average national egg weight of the chickens is 39-42 g. The national on-farm egg yield per year ranges from 40-45 eggs while it doubles (85-95 eggs) at on-station rearing under confinement.
Table 8. Egg parameters of Ethiopian indigenous chickens that have various morphologies |
|||||
Egg traits |
Black (Tikur) |
Naked neck (Melata) |
Red (kei) |
Gray (Gebsima) |
White (netch) |
Egg weight, g |
44 |
49 |
45 |
44 |
47 |
Egg mass, kg/bird/yr |
2.8 |
4 |
2.4 |
2.6 |
3.0 |
Egg shape index |
75.4 |
69.3 |
70.7 |
NA |
69.0 |
Shell thickness, mm |
0.37 |
0.31 |
0.38 |
NA |
0.32 |
Albumen, % egg |
50 |
49 |
51 |
49 |
49 |
Yolk, % egg |
36 |
38 |
38 |
36 |
36 |
Source: Teketel 1986; Abebe 1992, Mebratu 1997. NA: data not available |
The naked neck chicken have heavier egg weight, higher egg mass and yolk % of the egg but lower in egg shape index, shell thickness and albumen % of the egg.
Decades studies by different institutes revealed that Ethiopian indigenous chickens are characterized by low survival rate than the exotic breeds under confinement (Bigbee 1965; Teketel 1986; Brannang and Pearson 1990; Abebe 1992; Solomon 2003). The disease agent responsible for the devastation under confinement was recently diagnosed and related to Marek’s disease (MD). It was characterized by visceral tumor lesions and nerve paralysis of the wing and leg (Reta et al 2005). The sero-prevalence study of MD didn’t vary significantly with chicken types whereas their susceptibility to mortality from MD infection varied. The order of the rank from highest to lowest mortality was Jarso > Tepi > Horro > Konso > Tilili > Fayoumi during the pre MD vaccination. Grower (3-5 months) age groups are highly devastated in most chicken ecotypes except in Jarso chicken ecotype. Meanwhile, there is persistent skepticism about the fitness of indigenous chickens to confined management due to long-term adaptation and natural selection to be fit to free range scavenging system (Solomon 2003). However, contrary to such notion MD vaccination opened the door to rear them under confinement (Reta et al 2006 a and b). MD vaccination response varies with chicken ecotypes as measured using mortality rate as indicator. The level of response among the chicken ecotypes to MD vaccination and degree of mortality rate improvement (vaccine protection) to the virulent MD natural challenge varies in the rank order of Jarso > Horro > Fayoumi > Tepi as monitored up to 21 weeks age.
Table 9. Mortality of indigenous chicken ecotypes to natural MD infection pre and post MD vaccination |
|||||||
Monitoring mortality until 21 weeks age |
Arsi |
Jarso |
Konso |
Tepi |
Horro |
Tilili |
Fayoumi |
Brooder (0-2 months) age mortality, % |
93¶¶ |
59.9 |
26.6 |
37.2 |
25.3 |
27.4 |
6.2 |
Grower (3-5 months) age mortality, % |
34 |
43 |
60.1 |
54.4 |
63 |
58.3 |
8.2 |
Sero-prevalence (%)of MD by AGID test |
NA |
76.9 |
63.2 |
81.8 |
61.5 |
85.7 |
66.7 |
Pre MD vaccination mortality, % |
NA |
99† |
86.7 |
91.6 |
89 |
85.7 |
14.5 |
Post MD vaccination mortality in MD non-vaccinated control group, % |
NA |
63.7 |
NA |
44 |
48.6 |
NA |
5.2 |
Post MD vaccination mortality in MD vaccinated chicken group, % |
NA |
17.1† |
NA |
38 |
21.7 |
NA |
0% |
Source: Brannang and Pearson 1990; Reta et al 2005; Reta et al 2006a and b; NA: data not available. ¶¶The cause of mortality in Arsi ecotypes was not known. † Severe mortality in absence of MD vaccine. |
Under on-station confined conditions the health performance of indigenous chickens of different morphologies are assessed. High mortality is observed in the chickens of various morphologies as summarized in the next Table. The causative agents are suspected to be coccidiosis, chronic respiratory disease, Marek’s disease and Salmonella pollurum and nutritional deficiencies (Alamargot 1987). So far very little work is done on health problems at on-station.
Table 10. Mortality (%) at different life stages for indigenous chickens of different morphologies |
||||||||
Age |
Station |
Red (Kei) |
Black (Tikur) |
Silver (Kokima) |
Wessera |
Gray (Gebsima) |
White (Netchi) |
Naked neck (Melata) |
Brooder |
Haromaya |
23 |
8 |
27 |
30 |
22 |
NA |
NA |
Brooder |
Hawassa |
30 |
13 |
NA |
NA |
39 |
18 |
13 |
Grower |
Haromaya |
36 |
28 |
54 |
31 |
33 |
NA |
NA |
Grower |
Hawassa |
NA |
33 |
NA |
NA |
25 |
NA |
40 |
Source: Teketel 1986; Abebe 1992. NA: data not available |
The common external parasites in scavenging poultry include lice, fleas, mites, and ticks. Ecto-parasites suck the blood of the chickens to survive. In so doing, they cause anemia, irritate the host causing unstopping itching and scratching reflex, thus interferes with scavenging and feeding effort of the chickens. Therefore, they cause reduced feed intake, reduced weight gain, decreased egg production. Very limited work has been done on parasite epidemiology. According to NPPAR (2002), 8 species of ecto-parasites are identified in indigenous chickens of Ethiopia. The prevalence rate of ecto-parasites ranges from 90.5-93.6% (Hagos 2000).
The helminthes parasite burden (intensity of challenge) is very high in mid altitude than the other agro-ecologies. It indicates agro-ecology based variation in level of health threat in chickens due to parasitism. It also shows relative suitability of parasite-environment interaction to successfully complete its life cycle in the mid-altitude than the other agro-ecologies. Ecto-parasites and cystodes are more prevalent than nematodes among chicken population. However, studies on ecto and endo-parasites are not adequate to generalize the scenario.
Table 11. Average number of parasite burden per chick and prevalence in different agro-ecologies |
||||
Disease types |
Altitude based mean parasite burden/chick (Mean +SD) |
Total mean |
||
Highland |
Mid-altitude |
Lowland |
||
Ecto-parasites |
105+13.8 |
75.8+10.27 |
169+37.3 |
117+14.0 |
Cestodes |
128+21.0a |
219+31.6b |
124+19.9a |
157+14.5 |
Nematodes |
10.7+2.3 |
28.6+6.71 |
24.6+5.3 |
21.3+2.96 |
|
Altitude based parasite prevalence (%) |
Total |
||
Highland |
Mid-altitude |
Lowland |
||
Ecto-parasites |
NA |
NA |
NA |
90.5 - 93.6 |
Cestodes |
92a |
100b |
92a |
86.3 |
Nematodes |
66c |
79.6d |
70c |
75.8 - 90.5 |
Source: Hagos 2000; NPPAR 2002;
Fikre et al 2003
NA: not available. |
Table 12. Prevalence of different indigenous chicken diseases as assessed by various diagnostic methods |
|||
Disease category |
Pathogen Species |
Diagnosis method employed |
Prevalence, % |
Ecto-parasites |
- |
Visual observation |
93.6 |
Menopon gallinae |
" |
87.9 |
|
Menacanthus stramineus |
" |
87.2 |
|
Cestodes |
- |
Post mortem observation |
86.3 |
Raillietina echinodbothridia |
" |
65.3 |
|
H.cantaniana |
" |
66 |
|
R. tetragona |
" |
52.7 |
|
Heterakis spp |
" |
43.2 |
|
Subulura spp |
" |
33.1 |
|
Nematodes |
- |
Post mortem observation |
75.8 |
Ascaridia galli |
" |
47.3-55.3 |
|
Source: Hagos 2000; NPPAR 2002; Fikre et al 2003 |
A number of devastating viral and bacterial diseases of indigenous chickens are identified in scavenging system. They harbour diverse infectious pathogens. Apart suffering for themselves, the chickens of the scavenging system serve as a reservoir to disseminate the infectious agents to the nearby modern commercial poultry farms. Salmonella, Newcastle disease, coccidia, infectious coryza are some of the many as summarized from scant studies on infectious diseases.
Table 13. Prevalence of infectious and non-infectious diseases of chickens in scavenging system |
|||
Disease category |
Pathogen Species |
Diagnosis method employed |
Prevalence, % |
Coccidiosis |
- |
- |
20.0 |
|
Newcastle disease |
Indirect-ELISA |
43.7 |
Viral infections |
Lymphoid leukosis |
Clinical signs |
1.58 |
|
Marek's disease |
Clinical signs |
1.05 |
Bacterial |
Infectious coryza |
Clinical signs |
2.1 |
Colibaccilosis |
Clinical signs |
1.58 |
|
Salmonella pullorum &/or gallinarum |
Rapid serum agglutination |
64.2 |
|
Nutritional |
Calcium deficiency |
Clinical signs |
4.21 |
Disorders |
Ascites |
Clinical signs |
1.05 |
Blindness |
Clinical signs |
1.05 |
|
Hemorrhagic syndrome |
Clinical signs |
0.58 |
|
Cystic right oviduct |
Clinical signs |
6.84 |
|
Scaly leg |
Clinical signs |
19.5 |
|
Arthritis (traumatized leg) |
Clinical signs |
4.74 |
|
Proventriculus and gizzard hypertrophy |
Clinical signs |
12.5 |
|
Source: Mohammed 1998; Hagos 2000; NPPAR 2002; Fikre et al 2003 |
98.5% egg and 99.2% poultry meat of the total national production is contributed by indigenous chickens representing an output of 72,300 metric tons of poultry meat and 78,000 metric tons of egg (AACNC 1984; FAO2002). The per capita consumption is 57 eggs and 2.85Kg chicken meat per annum and is very low compared to international standards in Ethiopia. It comes mostly from indigenous chicks (Alemu 1987). They are one of the organic farming and free from antibiotics and other harmful residues to human diet and environment. They feed on animal parasites. Their manure serves for animal feed and crop fertilizer. They are also a valuable asset to the village life in providing nutrition and a small disposable income particularly for women and children. The next Table indicates that farmers without much effort, skill, and capital have replacement stock and fetch an income. If farmers strategically grow chickens for market during the eves of national festivals and religious ceremonies, the price of the egg and chickens double, and hence the income for the household is doubled. On other hand, improving via research extension their fertility and hatchability rate, survival rate, and individual and flock egg and meat production performance of indigenous chickens can have a great impact on the income of the household.
Table 14. Economics of indigenous chickens reared in scavenging system per household |
|||
|
Parameters of production |
Rate |
Quantity |
1 |
Mean number of female layers/house |
|
5 |
2 |
Cycle/year and egg number/cycle/ hen |
3cycle@17eggs/cycle/hen |
255eggs/yr per 5 hens |
3 |
Eggs set for hatching |
76% (of 255) |
194 eggs/yr |
4 |
Eggs consumed at home |
11% (28eggs/yr) @ 0.8 birr |
22.4 birr |
5 |
Eggs sold (number left from hatching) |
13%(33eggs/yr) @ 0.8 birr |
26.4 birr |
6 |
Hatched eggs for chickens |
70% of 194 |
136day-old chicks |
7 |
Survival of the offspring to weaning (8wk) |
40% of 136 |
54 growers |
8 |
Survival to selling age |
75% of 54 |
41 mature birds |
9 |
Replacement of the stock |
5 hen + 1 cock |
35 mature birds for sale |
10 |
Selling the rest chickens |
41-6 replaced hen |
|
11 |
Sex of the chicken for sale |
50% probability |
20 male+15female |
12 |
Market for male chickens |
40 birr/male chick |
800 birr/yr |
13 |
Market for female chickens |
30 birr/female chick |
450 birr/yr |
14 |
Total income after consumption at home |
1276.4 birr/yr |
|
Source: AACMC 1984; Teketel 1986; Tadelle 1996; Mebratu 1997; NPPAR 2002; Tadelle 2003. 1$ US dollar = 10.3 birr |
Some animal production scientists argue that the ecology in which indigenous Ethiopian chickens thrive i.e. the system of a low input-output level looks economically efficient. However, others strongly blame on the inefficiency of the system because of high mortality (60%) and unsuccessful brooding and poor growth of baby chicks. Still some development workers question the importance of indigenous chickens to fill the national protein gap and gross domestic poultry production and hence advocate focusing on exotic poultry breeds and insisting on distribution of exotic cockerels, pullets, day-old chicks and/or fertile eggs. Others are angry at marginalizing the chicks in decades of research and development work in that there would have been a significant improvement by selection and/or crossbreeding among a number of indigenous chickens if not neglected. In addition, they claim that the several years of effort on exotic chicken distribution to the rural farmers to bring a livelihood change on food and income source is unsuccessful. Hence, they advice not to marginalize the indigenous stocks that are developed through long term adaptation to separate ecology and evolution under differing natural selection pressures by climate, endemic diseases, available nutrition and criteria imposed by man.
Some animal genetists appreciate about the indigenous chicken’s disease resistance character and possession of some degree of natural immunity against some common diseases. Others criticize such idea as the indigenous chickens repeatedly failed to demonstrate the so-called disease resistant/tolerant character under confined management than exotic birds. There is worry in the minds of some that indigenous chicken genetic resources are inclined to rapid loss through many natural (disease and feed crisis) and manmade pressures including genetic dilution via decades exotic chicken distribution without due attention to its long term effect on the genetic diversity.
Little studies done on them lacks consistency. Some scientists follow region (ecotype) based classification while others follow chicken morphology to identify and characterize the chickens. For me, nesting chicken morphology under their regional (ecotype) location is preferable as both approaches have important merits. Therefore, apparently, from the aforementioned reports, one can see that the studies conducted so far clearly lacks clear direction and objectives towards sustainable improvement, utilization and conservation of our chicken resource.
Ethiopia is blessed with chicken genetic resources. However, the population census and distribution pattern is not adequately documented. The chickens are a pool of heterogeneous population with remarkable genetic variation within each ecotype and with moderate genetic variation between ecotypes. Both within and between variations are also manifested on their morphologies and on their biological performances. Their reproduction has variation between on-farm and on-station but poorly studied. Chickens originated from different regions (ecotypes) and chickens with different morphologies (plumage colors) have different levels of feed intake, feed conversion ratio, body weight, growth rate, egg parameters and health performance both at on-station and on-farm scavenging conditions. Under scavenging condition they grant the poor farmers with remarkable economic and nutritional benefits with little or without any inputs. However, they have received little attention in rural development and food security. They are also neglected from agricultural extension and development, thus their potential is under exploited and underutilized. Concurrently, our current knowledge about them is not adequate, not organized and not consistent.
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Received 19 January 2009; Accepted 29 January 2009; Published 5 August 2009