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BackgroundSheep is important in the socio-economic lives of people around the world. It is estimated that more than half of our once common livestock breeds are now endangered. Since genetic characterization of Nigerian sheep is still lacking, we analyzed ten morphological traits on 402 animals and 15 microsatellite DNA markers in 384 animals of the 4 Nigerian sheep breeds to better understand genetic diversity for breeding management and germplasm conservation.ResultsMorphological traits of Uda and Balami were significantly (P < 0.05) higher than Yankasa, which were both higher than West African Dwarf (WAD) sheep. Stepwise discriminant analysis showed tail length, rump height, chest girth, ear length and chest depth as the most discriminating variables for classification. Mahalanobis distances show the least differentiation between Uda and Balami and the largest between WAD and Balami sheep. While 93.3% of WAD sheep were correctly assigned to their source genetic group, 63.9% of Yankasa, 61.2% of Balami and 45.2% of Uda were classified correctly by nearest neighbour discriminant analysis. The overall high Polymorphism Information Content (PIC) of all microsatellite markers ranged from 0.751 to 0.927 supporting their use in genetic characterization. Expected heterozygosity was high for all loci (0.783 to 0.93). Mean heterozygote deficiency across all populations (0.171 to 0.534) possibly indicate significant inbreeding (P < 0.05). Mean values for FST, FIT and FIS statistics across all loci were 0.088, 0.394 and 0.336 respectively. Yankasa and Balami are the most closely related breeds (DA = 0.184) while WAD and Balami are the farthest apart breeds (DA = 0.665), which is coincident with distance based on morphological analysis and population structure assessed by STRUCTURE.ConclusionsThese results suggest that within-breed genetic variation in Nigerian sheep is higher than between-breeds and may be a valuable tool for genetic improvement and conservation. The higher genetic variability in Yankasa suggests the presence of unique ancestral alleles reflecting the presence of certain functional genes which may result in better adaptability in more agro-ecological zones of Nigeria. These genetic characteristics are potentially useful in planning improvement and conservation strategies in Nigerian indigenous sheep.

Application of multivariate principal component analysis to morphological characterization of indigenous goats in Southern NigeriaPhenotypic variation present in a population arises due to genotypic and environmental effects, and the magnitude of phenotypic variability differs under different environmental conditions, therefore, the purpose of this study was to objectively describe the linear type traits of extensively managed mature indigenous goats of Southern Nigeria and to predict body weight from their orthogonal shape characters using principal component analysis. Body weight and four body measurements namely, height at withers, neck length, body length and heart girth were measured in 265 randomly selected West African Dwarf (WAD) and Red Sokoto (RS) goats of both sexes. RS goats had significantly (P < 0.05) higher morphological traits compared to their WAD counterparts. Sexual dimorphism was observed in all the traits with higher values recorded for males. Phenotypic correlations among body weight and biometric traits were positive and highly significant (r = 0.76-0.91 versus 0.82-0.97 and 0.66-0.94 versus 0.83-0.91 for WAD and RS female and male goats, respectively). In the varimax rotated principal component factor analysis, two factors were extracted for each sex of the two breeds, although with varying degrees of factor loadings. The principal component based regression models, which are preferable for selecting animals for optimal balance, accounted for 89.00 and 96.00% as well as 81.00 and 91.00% of the variation in body weight of female and male WAD and RS goats, respectively. The information obtained could be useful in designing appropriate management, selection and breeding programmes for utilization of goat genetic resources.Key words: goats / autochthonous breeds / body traits / multivariate analysis / Nigeria Uporaba multivariatne analize glavnih komponent pri morfološki karakterizaciji avtohtonih koz v južni NigerijiFenotipska variabilnost v populaciji je pogojena z delovanjem genetskih in okoljskih dejavnikov. Ker je obseg fenotipske variabilnosti različen v različnih okoljih, smo skušali v tej študiji objektivno predstaviti linearne eksterierne lastnosti ekstenzivno vzrejanih avtohtonih koz v južni Nigeriji in z analizo glavnih komponent napovedati telesno maso na osnovi lastnosti, ki opredeljujejo njihovo telesno obliko. Izmerili smo telesno maso in štiri telesne mere (višina v vihru, dolžina vratu, dolžina trupa in obseg prsi) pri 265 naključno izbranih zahodno afriških pritlikavih kozah (West African Dwarf, WAD) in rdečih sokoto kozah (Red Sokoto, RS) obeh spolov. Vrednosti za merjene lastnosti so bile pri RS kozah statistično značilno (p < 0,05) večje kot pri WAD kozah. Spolni dimorfizem smo zabeležili pri vseh lastnostih, z večjimi vrednostmi za samce. Fenotipske korelacije med telesno maso in biometričnimi lastnostmi so bile pozitivne in statistično visoko značilne (r = 0,76-0,91 in 0,82-0.97 ter 0,66-0,94 in 0,83-0,91 za WAD in RS živali ženskega ter moškega spola). S faktorsko ana...

Coat colour contributes to physiological adaptation in mammals and mediates response to thermal stress. Twenty-four adult West African Dwarf sheep of both sexes and with different coat colour types were used in this study. We measured rectal temperature (RT), respiratory rate (RR) and pulse rate (PR) before sunrise and sunset during the late dry season (January-March) and early rainy season (April-June) as well as packed cell volume (PCV), red blood cell (RBC) count, white blood cell (WBC) count, plasma sodium (Na(+)) and potassium (K(+)). Animals with black coat colour had the highest (P < 0.05) mean values of 38.92 ± 0.03 °C, 65.09 ± 1.06 breaths/min, 81.35 ± 0.78 beats/min, 1.70 ± 0.01 for RT, RR, PR and heat stress index (HSI), respectively, followed by brown mouflon and brown with extensive white, while the Badger Face coloured sheep had the least mean values. There were significant (P < 0.05) differences between male and female sheep for RT, RR, PR and HSI. Season had a significant (P < 0.05) effect on RT, RR, PR and HSI. Coat colour and sex also significantly (P < 0.01) affected RBC, WBC, Na(+) and K(+). Seasonal variation (P < 0.05) in all the blood parameters was observed, with the exception of PCV. Interaction effect of coat colour and sex was significant (P < 0.05) on RT and HSI. Correlation coefficients among the measured traits ranged from positive to negative values. These results indicate that selection of white-coloured sheep to attenuate heat stress is desirable in the hot humid tropics.

The objectives of this study were to investigate the relationships between body weight and morpho-structural indices to predict body weight from their orthogonal body shape characters using principal component analysis and to morphologically classify the chicken genotypes using multivariate discriminant analysis. Data used were from 273 randomly selected 12-weeks-old indigenous chickens of normal-feathered (NF), frizzle-feathered (FF), naked-neck (NN) and Anak Titan (AT) genotypes. Phenotypic correlation among body weight and most biometric traits ranged from 0.227-0.876, -0.7-0.901, 0.034-0.968 and -0.207-0.849 for NF, NN and AT chickens, respectively. Factor analysis with varimax rotation of interrelated traits revealed three principal components which accounted for 83.1%, 74.4%, 78.8% and 76.5% of the total variance in NF, FF, NN and AT chickens in the order listed. Breast girth, keel length, thigh length, shank length and wing length were found to be the most discriminating variables to separate the chicken genotypes. The longest distance (72.54) occurred between AT and NF genotypes while the shortest distance (4.27) was recorded for FF and NN genotypes. Classification results showed that 85.2% of AT genotype was correctly classified into their source population. However, 22.7% of NF was misclassified as NN, while 33.3% of NN was misclassified as NF chickens. These results suggest that there is high rate of gene flow between these two indigenous chicken genotypes. Information obtained from this study may be considered useful in breed improvement programmes for selection, characterization, conservation and better management of Nigerian indigenous chickens.