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The exposure of sheep to elevated ambient temperatures induces an increase in the dissipation of excess body heat, in order to overcome this excessive environmental heat load. Dissipation of excess body heat is emitted by evaporation of water from the respiratory tract and skin surface via panting and sweating.The following heat stress traits were measured; body temperature, rectal temperature, pulse rate and respiratory rate after the sunrise and before the sunset. While blood and serum biochemical indices measured were blood glucose, total serum protein, globulin, cholesterol and triglycerides. No significant relationship(P>0.05) was recorded between heat stress traits and blood biochemical indices studied. However, we observed a positively significant (P

The tenascin-XB (TNXB) gene has antiadhesive effects, functions in matrix maturation in connective tissues, and localizes to the major histocompatibility complex class III region. We hypothesized that it may influence adaptive physiological response through an effect on blood vessel function. We identified a novel g.1324 A→G polymorphism at a TaqI recognition site in a 454 bp fragment of ovine TNXB and genotyped it in 150 Nigerian sheep using PCR-RFLP. The missense mutation changes glutamic acid (GAA) to glycine (GGA). Among SNP genotypes, significant differences (P

The DQB1 locus is located in the major histocompatibility complex (MHC) class II region and involved in immune response. We identified 20 polymorphic sites in a 228 bp fragment of exon 2, one of the most critical regions of the MHC DQB1 gene, in 60 Nigerian goats. Four sites are located in the peptide binding region, and 10 amino acid substitutions are peculiar to Nigerian goats, compared with published sequences. A significantly higher ratio of nonsynonymous/synonymous substitutions (dN/dS) suggests that allelic sequence evolution is driven by balancing selection (P < 0.01). In silico functional analysis using PANTHER predicted that substitution P56R, with a subPSEC score of −4.00629 (Pdeleterious = 0.73229), is harmful to protein function. The phylogenetic tree from consensus sequences placed the two northern breeds closer to each other than either was to the southern goats. This first report of sequence diversity at the DQB1 locus for any African goat breed may be useful in the search for disease-resistant genotypes.

Pigmentation plays important adaptation and physiological efficiency roles in animals. In the sequence of a 648 bp fragment representing intron 1, exon 2, and part of intron 2 of the MLPH mammalian pigmentation gene, we identified a novel g.469C> G mutation in intron 2, and genotyped it in 266 Nigerian goats using PCR-RFLP analysis. The C allele had frequencies of 0.9625, 0.9804 and 0.97405 in West African Dwarf (WAD),Sahel(SH) and Red Sokoto (RS) breeds, respectively. The G allele was the highest in WAD (0.0375), followed by RS (0.02595), and then SH (0.0196). Overall low FIS and FST and high Nm values demonstrate little differentiation within and among the goat breeds at this intronic locus. This g.469C> G polymorphism in MLPH gene is the first in any goat breed and also first in Nigerian goats. Our results suggest that this intronic SNP locus is maintained at Hardy-Weinberg equilibrium (P

Trypanosomosis remains a major challenge to livestock production in much of tropical Sub-Saharan Africa, while diagnosis and treatment still depend on inefficient parasitological techniques. Endemic infections depend on animal reservoirs with subclinical parasitemia. We report molecular diagnosis of subclinical Trypanosoma vivax (T. vivax) infection using polymerase chain reaction (PCR) for the first time in Nigerian goats and associate parasite presence with gross physiological traits and serum metabolites in extensively managed Nigerian goats. PCR was used to amplify a 400 bp DNA fragment of the parasite genome in 205 goats across three geographical zones of the country. Results showed a high subclinical infection rate (SCIR) of 71.7% in the total goats examined. Overall SCIRs of 71%, 75.9% and 55.6% were recorded in West African Dwarf, Red Sokoto and Sahel goats respectively, while geographical SCIRs were 71.2% (Southwest), 75% (Northwest) and 70% (Northeast). T. vivax presence had significant (P 0.05) effect on respiratory rate and is associated with higher creatinine levels in sera. Logistic regression analyses with Hosmer-Lemeshow goodness-of-fit showed that respiratory rate is the most important predictive trait for the presence of T. vivax infection (P 0.05). Goats appear to be a viable reservoir for T. vivax infection of other livestock. Molecular diagnosis of subclinical trypanosomosis using PCR could be useful for large scale epidemiological studies, early diagnosis of subclinical infection and treatment of the disease in extensively managed tropical goats.

Los recursos ganaderos autoctonos son de caracter estrategico en los aspectos socioeconomicos de los sistemas agricolas para garantizar la seguridad alimentaria en los paises de escasos recursos. Por lo tanto, conocer mejor la importancia de la variabilidad genetica es vital para su futura utilizacion, por medio de la conservacion. Se presenta el primer analisis de la diversidad genetica en ovejas de Nigeria basado en la region de control (D-loop) del Ovis aries del genoma mitocondrial, utilizando 1.179 bases entre las posiciones 15.437 y 16.616 de pares de bases. Una muestra de 290 animales, compuesta por las razas Balami, West African Dwarf (WAD), Uda y Yankasa, fue tomada al azar de toda Nigeria. Se observaron noventa y seis (96) haplotipos, con una alta diversidad media en cuanto a estos de 0,899 ± 0,148. La diversidad genetica fue mayor en la raza Uda (0,921 ± 0,021) y menor en la raza WAD (0,852 ± 0,061). Los indices de poblacion especificos FST variaron de 0.00133 en la raza Uda a 0,00335 en la razaWAD. La raza Yankasa presento el mayor numero de posiciones polimorficas (201), mientras que el menor lo mostro la raza Uda (96). Analisis de la varianza molecular revelo que 0,23% de la variacion se encuentra entre las poblaciones, en comparacion con el 99,77% de variacion que se encuentra dentro de las poblaciones. El arbol filogenetico indica que los linajes mitocondriales de las razas ovinas partieron de un origen comun en conformidad con la primera divergencia de la raza Yankasa, seguida por WAD, mientras que las razas Balami y Uda se encuentran mas estrechamente relacionadas. Estos resultados demuestran que la divergencia evolutiva de las poblaciones ovinas de Nigeria, basados en el ADN mitocondrial de la region control, puede coincidir con la distribucion geografica en Nigeria e indican una tasa importante de cruzamiento entre ellas. Esto podria tener ventajas desde el punto de vista de la gestion de la mejora y las estrategias de conservacion y preservacion a largo plazo de las ovejas autoctonas de Nigeria.

The agouti-signaling protein (ASIP) plays a major role in mammalian pigmentation as an antagonist to melanocortin-1 receptor gene to stimulate pheomelanin synthesis, a major pigment conferring mammalian coat color. We sequenced a 352 bp fragment of ASIP gene spanning part of exon 2 and part of intron 2 in 215 animals representing six goat breeds from Nigeria and the United States: West African Dwarf, predominantly black; Red Sokoto, mostly red; and Sahel, mostly white from Nigeria; black and white Alpine, brown and white Spanish and white Saanen from the US. Twenty haplotypes from nine mutations representing three intronic, one silent and five missense (p.S19R, p.N35K, p.L36V, p.M42L and p.L45W) mutations were identified in Nigerian goats. Approximately 89 % of Nigerian goats carry haplotype 1 (TGCCATCCG) which seems to be the wild type configuration of mutations in this region of the gene. Although we found no association between these polymorphisms in the ASIP gene and coat color in Nigerian goats, in-silico functional analysis predicts putative deleterious functional impact of the p.L45W mutation on the basic amino-terminal domain of ASIP. In the American goats, two intronic mutations, g.293G>A and g.327C>A, were identified in the Alpine breed, although the g.293G>A mutation is common to American and Nigerian goat populations. All Sannen and Sahel goats in this study belong to haplotypes 1 of both populations which seem to be the wild-type composite ASIP haplotype. Overall, there was no clear association of this portion of the ASIP gene interrogated in this study with coat color variation. Therefore, additional genomic analyses of promoter sequence, the entire coding and non-coding regions of the ASIP gene will be required to obtain a definite conclusion.

Background Sheep 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. Results Morphological traits of Uda and Balami were significantly (P F ST , F IT and F IS 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. Conclusions These 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.