Nigerian Goat Breeds Research Articles

Population Genetic Structure and Gene Flow Among Nigerian Goats

Population Genetic structure in 200 indigenous goats sampled across four states from the South-Western and South Southern region of Nigeria was assessed using 7 microsatellite DNA markers. Observed Analysis of molecular genetic variation (AMOVA) was higher within populations (3.47) than among populations (1.84) accounting for 71% and 29% of the total genetic variation respectively. Population structure analysis clustered Nigerian goats into 2 distinct groups with Sahel (SA) and Red Sokoto (RS) forming a cluster on one side and WAD on the other. Highest gene flow values (3.46) were observed between Ibadan Sahel (IBSA) and Port-Harcourt Sahel (PHSA) goats, while the least (0.25) was recorded between Abeokuta West African Dwarf (ABWAD) and Abeokuta red Sokoto (ABRS) goat populations. It was conclude that there is a good measure of genetic diversity that can be harnessed for planned genetic improvement and confirms that there is indiscriminate flow of gene within and among Nigerian goat breeds.

Comparative multivariate analysis of biometric traits of West African Dwarf and Red Sokoto goats

The population structure of 302 randomly selected West African Dwarf (WAD) and Red Sokoto (RS) goats was examined using multivariate morphometric analyses. This was to make the case for conservation, rational management and genetic improvement of these two most important Nigerian goat breeds. Fifteen morphometric measurements were made on each individual animal. RS goats were superior (P<0.05) to the WAD for the body size and skeletal proportions investigated. The phenotypic variability between the two breeds was revealed by their mutual responses in the principal components. While four principal components were extracted for WAD goats, three components were obtained for their RS counterparts with variation in the loading traits of each component for each breed. The Mahalanobis distance of 72.28 indicated a high degree of spatial racial separation in morphology between the genotypes. The Ward's option of the cluster analysis consolidated the morphometric distinctness of the two breeds. Application of selective breeding to genetic improvement would benefit from the detected phenotypic differentiation. Other implications for management and conservation of the goats are highlighted.

Evaluation of different crossbreeding programmes, season and sex on birth weight and linear traits of Nigerian goats

Data from 600 Weaner (300 male and 300 females) kids from crossbreeding programmes derived from the mating of two Nigerian breeds of goat, namely West African Dwarf (WAD) and Red Sokoto Goat (RSG) were used for the study. The mating types were WAD x WAD (F1) – Genotype – 1 (Savannah ecozones), RSG x WAD – Genotype 11, RSG x F1 (F2 back cross) – genotype 111. WAD x RSG – genotype IV. Twelve Bucks and 12 Does were selected from each of (Sahel, coastal and Savannah) the ecozones according to the breeding programme. The study was conducted at the Enugu State University of Science and Technology, Abakaliki Campus between 1995 and 2000. the aim was to evaluate the effect of different crossbreeding programmes, season and sex on birth weight and linear traits of Nigerian goat kids. The birth weight means and linear traits for the six breeding groups were significantly (P < 0.05) different. Season of rearing and sex significantly (P < 0.05) affected the birth weight. Of the kids with late rainy season (July - September) having significantly higher birth weight. Male animals excelled the females on birth weight, chest and head circumference. The result suggests that the crossbreeding programme involving RSG x F1 (F2 back cross) – genotype III displayed superior birth weight and chest circumference and should be tested, inbred and if found productive and adaptive, it could then be recommended to the breeder farmers' fixation or commercial crossing for meat production. The information on the effect of sex, and season on the growth is useful in improvement programme through crossbreeding. Keywords: Crossbreeding programmes, Birth weight, Linear traits, Nigerian goat breeds Agro-Science Vol. 4 (2) 2005: pp. 34-37

Chronic caprine mastitis in Nigerian goat breeds: microbiological flora and histopathological findings

In a study involving lactating does with normal-sized and enlarged pendulous udders, 85.5% of milk samples obtained from does with unilateral udder enlargement and 84.8% of samples from bilaterally enlarged udders indicated the presence of intramammary inflammation based on results of the modified Whiteside test. In contrast, only 47.6% of milk samples obtained from normal-sized udders showed evidence of intramammary inflammation. Bacterial cultures were performed on all milk samples which showed evidence of intramammary inflammation. 16 species of bacteria and other microorganisms were cultured from these samples. Bilaterally enlarged udders collectively yielded 13 different microbial isolates, while unilaterally enlarged udders yielded 11, and normal-sized udders yielded 9. The most frequent isolates in all groups were Staphylococcus spp. and Corynebacterium spp. On histopathologic examination, severe pathological changes in the teat and udder tissues of enlarged pendulous udders were observed. Lesions in parenchymatous tissues showed mild to severe inflammation with involution of the parenchyma of glands. This led to shrinkage of the alveoli and in severe cases, their complete disappearance and replacement by fibrous connective tissue which was observed to have a high degree of proliferation. Sections of non-pendulous udder tissue showed proper arrangement of alveoli with hypertrophic epithelial cells, indicating active secretory activity. The results provide some definitive evidence that enlarged pendulous udder development in some Nigerian breeds of goats is not spontaneous but occurs largely as a result of incursion of the mammary glands by pathogenic organisms which may cause mastitis resulting in progressive dysfunction of mammary tissue. In chronic cases, there is severe atrophy of glandular tissue leading to fibrosis.

The Phenotype and Gene Frequencies of Polymorphic Haemoglobins of Nigerian Goat Breeds

Electrophoretic analysis 4I4 blood samples from adult Red Sokoto (Maradi), Kana Brown and Saltel (Maidugnri) goats shows that the first 2 breeds contain at least 3 electro-phoretically distinct types of haemoglobin. These are similar to those described by Braide & Enyenihi (I969) for the Kano Brown goats. Starch gel electrophoresis of the Saliel goats’ haemoglobins using a continuons buffer system yielded at least 4 electroplwretically distinct types, 3 of which are identical with those of the first 2 goat breeds. The fourth type is extremely slow in its migration towards the anode. The frequencies of the haemoglobin homozygote and heterozygote genotypes in the 3 goat breeds are compared. The genetic implications of the policy of preventing cross breeding of the Red Sokoto with other goats in Sokoto province is discussed.

Haemoglobin Types in Some Nigerian Goat Breeds

SUMMARY Studies of the electrophoretic mobility patterns of haemoglobin preparations from 3 breeds of Nigerian goats indicate that there are at least 3 haemoglobin types in goats. These types include one haemoglobin with relatively fast migration toward the cathode, another with relatively slower migration, and a third haemoglobin with intermediate electrophoretic mobility. The occurrence of more than 2. haemoglobin types in goats has not been hitherto reported.