Evidence abounds that Nigeria as a Nation is endowed with surplus natural resources that will make her self-sufficient in animal protein production and even become main exporters of all kinds of food items. According to Nigerianet (2003), Nigeria, being the largest geographical unit in West Africa, has a land area of 923,768 square kilometers. According to Central Bank of Nigeria, CBN (2002), Nigeria population was reported to be 129.9 million in 2004 based on the projected annual growth rate of 2.8% of the revised 1991 census. At this given growth rate Nigeria population is estimated to be 141.1 million in 2007. Nwosu (1989) reported that of the one hundred and thirty three million (133,000,000) chickens in Nigeria, one hundred and twenty-three million (123,000,000) are local chickens. RIM (1992), reported that the native chickens constituted 80% of the one hundred and twenty million (120,000,000) chickens in Nigeria. This showed that ninety-six million (96,000,000) were native chickens.
The fact that some developed countries with far less natural resources can still boast of self sufficiency and their ability to export poultry products call for sober reflection among Nigerians. Frommer (2006), the Israeli Ambassador to Nigeria, reported that Nigeria’s geographical territory is 30 times bigger than that of Israel and it’s population is 20 times larger than that of Israel. Annual rainfall in Israel ranges from 28 inches (70cm) in the north to less than 2 inches (5cm) in the south. Despite the obvious disparity in natural resources between Nigeria and the State of Israel, it is believed that the Israel model of agricultural and research development with some necessary modifications could be applied in Nigeria. Israeli livestock output for instance, in 2004 was worth US $1.4 billion (39%) and crops US $2.5 billion (61%). Israel produced almost 70% in monetary terms of its food requirements. The recent purchase of twenty five thousand (25,000) day old broiler chicks from Israel by the Animal Science Department of the University of Nigeria, Nsukka, in her HUJII broiler project, to a large extent, substantiates the Israeli Ambassador’s claims.
Moreover, the records of numerous poultry breeds genetically developed in other continents as far back as the nineteenth century is equally interesting. According to the New Encyclopedia Britannica (1995) the Barred Plymouth Rock, the American breed of importance today was developed in 1865 by crossing Dominique with the Black Cochin. The Wyandotte (an America breed) developed from five or more strains and breeds has eight varieties. Rhode Island Red (RIR) developed in 1857 was from red Malay game fowl crossed with reddish coloured shanghais with some brown leghorn, Cornish, Wyandotte and Brahma blood. It is good for meat production and one of the top meat breeds for the production of egg. It has bright red feather. New Hampshire was developed in US in 1930 from Rhode Island Red. It is a meat and early maturing breed. The white Leghorn especially developed in the USA, is one of the 12 varieties of the Leghorn breed which originated in Italy, a Mediterranean breed. The white Leghorn is the leading egg producer of the world. Cornish, an English breed, developed for crossbreeding programmes for broiler production was developed in England before 1893. It is a poor egg producer. The white Plymouth was registered in USA in 1888. Brahma is the only Asiatic breed of significance today developed in India. It has three varieties. The breeds of chicken are classified into American, Mediterranean, European and Asiatic, depending on the regions of the world where they were developed. The shika brown breed has been developed in NAPRI, Shika, Zaria. That means there is no African class of chicken. This buttresses the fact that while the Europe, America and Asia have for over a century been milking great income from their developed poultry breeds and other developed natural resources, Africa including Nigeria has been sleeping and groping in the dark due to many technical, socio-economic, organizational, constitutional and institutional problems.
These considerations pose some urgency on animal scientists and the entire nation of the need to put into motion every programme and action that will make it possible for our nation, Nigeria, to consolidate its claim as the “giant of Africa”. Nigeria would have to fulfil the proverb, “the proof of the pudding is in the eating”, by developing breeds of poultry for Africa that will be called truly African breeds. It could be observed with some confidence that the various studies carried out on gene characterization; improvement potential for meat and egg production; biometric, allometric and anthropometric indices of the Nigerian local chicken in cited works of Hill (1954), Nwosu (1990); have served enough background work to justify actual breeding plans for breed development in Nigeria in the 21st century. These studies done in the past laid a foundation for the recent findings that the light and heavy ecotypes both genetically and phenotypically differ (Momoh 2005). Management and nutrition affect the performance of both the heavy ecotype and the light ecotype. Heavy ecotype performs better than light ecotype and the battery cage performance has an edge over that in the deep litter (Tule 2005). The local chicken by nature is rugged and would require a feed of intermediate standard rather than depending on/or adopting the standard form from improved breeds put forward by NRC (Tule 2005). The relevance of the ongoing Ph. D research works of Ogbu, Cosmos and Ewa, Vivian, who are supervised by Professor Emeritus Dr. C.C. Nwosu on selection for growth and egg laying parameters on the heavy ecotype and light ecotype of the Nigerian local chicken is indisputable in the characterization of the local chicken of Nigeria. The researches and findings so far carried out on the Nigerian local chicken put the goal of breed development in Nigeria on course. The findings will provide the basis for the development of a poultry breed in Nigeria.
Great care, therefore, must be taken to equally develop the best plan that can maximally utilize the information found on the Nigerian Heavy and Light ecotype chicken for the purpose of developing a new breed at a minimal cost and shortest possible time. According to FAO (2004), strategies to develop poultry breeds suitable for family poultry in tropical countries must differ from those used in intensive production and should focus on improving indigenous breed, while also making use of pure, exotic and crossbred chickens where appropriate. FAO (2004) and Nwosu (1989) recommended the following rules in improving the Nigerian breed (i) Germplasm in the traditional condition should not be modified until management and housing have been improved, even then selection should be restricted to local breed, FAO (2004). (ii) When technical conditions are optimum and a ready market exist for the products, then the improved breeds, crosses and hybrid that have been selected for high performance can be introduced into the peri urban system even at small scale level (FAO, 2004). Hence according to Nwosu (1989) (an unpublished research work) care must be taken to avoid the mistakes of the scientists and government of Nigeria in the past before publication of Agricultural policy for Nigeria, which almost destroyed the hardy and less productive local breeds by indiscriminate crossing of local breeds of livestock and poultry. Replacement of local breeds with exotic breeds as a development strategy is a wrong strategy. Any breeding programme that excludes local genetic resource may be unrealistic. Appropriate rules and breeding programmes for the development of Nigeria breeds of poultry may indeed include pure breeding and selection programmes of the heavy and light ecotypes of the Local chickens in order to produce a Nigerian broiler, layer or dual purpose.
Pure breeding is a type of inbreeding where by mating is carried out between relatives (Pirchner 1969) or inbreeding involves mating between a male and female who are more related than the average of the population. Pure breeding of heavy ecotype of Nigerian local chicken means a mating between a heavy ecotype male and heavy ecotype female. Burdette (1963) described this kind of mating as incross, which is one of the four kinds of mating. Other matings include crosses, backcrosses and intercrosses. Allelemorph A and its alternative allele may be used to describe dominant and recessive alleles on a particular locus. AA x AA and aa x aa represent matings of like homozygotes or incrosses. Purebreeding of the heavy ecotype can be designated as AA x AA whereas that of the light ecotypes as aa x aa. The breeding system was also categorized into seven systems by Burdette (1963). The purebred experimental work will make use of the first breeding system (random-mating system). According to Pirchner (1969) the principal tools for improvement are selection, inbreeding and crossing. Which of these combinations to use depends on the species, breeding goal, trait, breeding structure and other considerations. If the additive – genetic variance is reasonably important, selection is the proper method. If genotypic variation is non-additive, selection alone will be inefficient. If dominance, particularly over dominance effect, is operational, inbreeding followed by crossing or selection will be successful. At any rate crossbreeding is important. If epistatic effect is the mode of gene action, inbreeding and selection are efficient. Pedigree breeders particularly elite group must practice pure breeding or even inbreeding and selection (Pirchner 1969).
1.1 Objectives of The Pure Breeding Experiment
(A) MAIN OBJECTIVE: To achieve a genetic improvement of the heavy ecotype of the local chickens of Nigeria through like to like matings.
(B) SPECIFIC OBJECTIVES:
- To investigate data on body weight, body weight gain, egg performance of purebreds of the heavy ecotype of the Nigerian local chicken and make comparisons between the purebred generation and the random-bred population of heavy ecotype in the farm.
- To determine body length, shank length, feather, beak and egg colour characteristics of the random-bred population and purebreds of the heavy ecotype of the local chicken and make comparisons between them.
- To investigate the hatchability percentages so that the best condition for hatchability using the backward integration method can be determined.
- To estimate the heritability of body weight, body weight gain, body length, shank length, feather colour, beak and egg colour through the sire components analysis (Sib analysis or Estimation of heritability from half Sibs).
- To investigate other genetic parameters such as correlation and regression coefficients.
- To estimate feed indices such as feed intake, feed efficiency, (kg/g of gain) and feed cost per purebred for the various ages; 0-8 weeks, 8-20 weeks and short term egg production.
Intensive research work on the local chicken is justified by the following reasons:
- The renowned scientific work of Maughan (1978) showed that good health starts with good nutrition. Scientific research has linked the consumption of saturated fatty acids, found predominantly in animal fats, with increased levels of cholesterol and a higher risk of heart attacks, while the unsaturated variety from vegetable oils and chickens do not have that effect. The findings of Obanu et al (1985) that the local chicken appears more compact and yield more meat per unit of live weight than the exotic; and contains smaller molecular weight fats with low Saponfication value indicate the need to develop a local (Nigerian) breed of poultry with lean meat is possible and very urgent.
- The problems of low animal protein intake in Nigeria will
tremendously be addressed when novel indigenous breeds are developed through pure breeding to cause chicken meat and egg prize to drop drastically.
- Hitherto, work on the local chicken has been too broad. Researchers refer to the local chicken as if all local brids are of the same size or possessing the same characteristic. Through the works of Momoh (2005) and Tule (2005) it has become clear that there are light and heavy ecotypes of the local chicken.
- Since FAO (2004) and Nwosu, (1989) unprinted research work recommended that the germplasma of the local chicken should not be unscrupulously modified but must be jealously preserved; this suggests that the gene pool of the heavy and light ecotype of the Nigerian local chicken should be preserved and utilized through pure breeding.
- The two tools for genetic improvement are mating method or breeding system and selection (Burdette, 1963). It will be important to aggregate the genetic potentials of the heavy ecotype through pure breeding research especially considering the recent reports of Tule (2005) that the heavy ecotype perform better than the light ecotype.
Pure breeding of the heavy ecotype of the Nigerian local chicken presupposes the mating of heavy ecotype males with the heavy ecotype females on a continuous basis for purification. This is the same as mating of relatives, since all heavy ecotypes of the Nigerian local chicken have the same ancestors.
- Development of the indigenous species of poultry into pure breeds of known genetic merit will add value to our animal genetic resources.
- Such Nigerian breeds of poultry when utilized commercially will largely increase the Gross Domestic product (GDP) of the Nation and greatly enhance our economy.
- Nigeria as a nation, desperately would needs to reduce the cost of foreign exchange expenditure incurred through the importation of fertile eggs, day old chicks and parent stock to Nigeria. An indigenous broiler, layer or dual purpose breed developed through pure breeding and selection methodology would not only terminate this problem but also at the same time become a major source of generating foreign exchange.
- According to Pekinbantams (2005), the United Kingdom, Australia, South Africa and America have their individual breed and colour standards. Nigeria also has need for her own breed and colour standards as it will lead her to the path of self- sufficiency instead of importation of finished products from abroad.