Publications

The present study suggests the existence of an association between milk production traits and genetic polymorphisms at the growth hormone (GH) gene in the Portuguese indigenous Serrana goat. The DNA from 229 animals of two ecotypes (Jarmelista and Ribatejano) was analysed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique revealing a high degree of genetic polymorphism at the goat GH (gGH) gene. Two conformation patterns were detected in exons 1 and 2, 6 in exon 3, 10 in exon 4 and 5 in exon 5. The evaluation of an association effect between these SSCP patterns with milk, fat and protein yields and fat and protein percentages suggests a positive effect of pattern A/B of exon 4 for Ribatejano ecotype and of pattern A/B of exon 2 for Jarmelista ecotype with milk yield (P<0.05) and of pattern A/B of exon 1 and pattern B/B of exon 2 with protein percentage (P<0.05) for Ribatejano ecotype. The results support the hints suggested by previous studies of the importance of the gGH gene as a candidate gene for marker-assisted selection in goat breeds and suggest that exon 4 is a preferential target for further investigation on mutations that influence milk yield variation.

The present study suggests the existence of an association between milk production traits and genetic polymorphisms at the growth hormone (GH) gene in the Portuguese indigenous Serrana goat. The DNA from 229 animals of two ecotypes (Jarmelista and Ribatejano) was analysed by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) technique revealing a high degree of genetic polymorphism at the goat GH (gGH) gene. Two conformation patterns were detected in exons 1 and 2, 6 in exon 3, 10 in exon 4 and 5 in exon 5. The evaluation of an association effect between these SSCP patterns with milk, fat and protein yields and fat and protein percentages suggests a positive effect of pattern A/B of exon 4 for Ribatejano ecotype and of pattern A/B of exon 2 for Jarmelista ecotype with milk yield (P<0.05) and of pattern A/B of exon 1 and pattern B/B of exon 2 with protein percentage (P<0.05) for Ribatejano ecotype. The results support the hints suggested by previous studies of the importance of the gGH gene as a candidate gene for marker-assisted selection in goat breeds and suggest that exon 4 is a preferential target for further investigation on mutations that influence milk yield variation.

The study was to determine the prevalent diseases of three native Nigeria goat breeds reared in the same environment for a period of 5 years (1995–1999). The indigenous goat breeds used were the Red Sokoto (RS), West African Dwarf (WAD) and their crossbreeds (CB). The prevalent diagnoses included mange, tick and flea infestations, helminthiasis, pneumonia, peste des petits ruminants (PPR), orf, abortion/stillbirth and premature delivery. Only the WAD had prevalence of helminthiasis, orf and premature delivery. The CB group had greater prevalence (P<0.05) of tick and flea infestations and of abortion/stillbirth than the other breeds. Age group had no influence on the prevalence of most of the diagnosed diseases. The kids were the major age group affected by orf. Seasonal variation in disease prevalence also was observed with mange and helminthiasis occurring during early- and late-rainy seasons. Seasons and genotype are therefore important factors affecting the prevalence and susceptibility of goats to diseases in the equatorial zone of southeastern Nigeria.

The study was to determine the prevalent diseases of three native Nigeria goat breeds reared in the same environment for a period of 5 years (1995–1999). The indigenous goat breeds used were the Red Sokoto (RS), West African Dwarf (WAD) and their crossbreeds (CB). The prevalent diagnoses included mange, tick and flea infestations, helminthiasis, pneumonia, peste des petits ruminants (PPR), orf, abortion/stillbirth and premature delivery. Only the WAD had prevalence of helminthiasis, orf and premature delivery. The CB group had greater prevalence (P<0.05) of tick and flea infestations and of abortion/stillbirth than the other breeds. Age group had no influence on the prevalence of most of the diagnosed diseases. The kids were the major age group affected by orf. Seasonal variation in disease prevalence also was observed with mange and helminthiasis occurring during early- and late-rainy seasons. Seasons and genotype are therefore important factors affecting the prevalence and susceptibility of goats to diseases in the equatorial zone of southeastern Nigeria.