Indexes of primarity in goats from Northern Cameroon and Chad

Abstract

In June 1992, a survey on caprine genetic resources was carried out in 12 sites (5 in Northern Cameroon and 7 in Chad) as part of a regional research project on small ruminants (Projet régional de recherches sur les petits ruminants : PRRPR) in Niger, Cameroon and Chad. A total of 215 adult female goats (105 from Northern Cameroon and 110 from Chad) was examined. As the animal populations exhibit a great variability of aspects after domestication, resulting from the accumulation of mutants which are not longer eliminated by natural selection, considerably attenuated by the protection provided by man, this phenomenon was used to measure the degree of belonging to the taxonomic category called “primary population”. Two indexes were thus applied : the index of primarity loci in segregation (IPs) and the index of primarity Agoutí locus (IPa). These two indexes varied from 0 (completely standardized breed: no variability in the aspect) to 1 (total primarity: conservation of all the accumulated variants from the first domestication). The IPs values represented 0.77 in Northern Cameroon and 0.84 in Chad while the IPa reached 0.75 in Northern Cameroon and 0.88 in Chad. These very high values indicate that in both countries these populations may be considered as almost primary populations, at least with this type of measurement. These values are very close to those exhibited by the populations (also considered as primary populations) in the Mediterranean area and in Brazil [the SRD (Sem Raça Definida) from Ceará]. The indexes could be used, at least as a first approach, for the mapping of caprine genetic resources of Africa.