Phenotypic diversity of the domestic donkey (Equus africanus Asinus) in the Sudano-Sahelian Zone of Cameroon

Abstract

This study was carried out in the Sudano Sahelian Zone of Cameroon to contribute to a better understanding of the biodiversity of donkeys of the area. 205 adult donkeys (111 males and 94 females) were randomly sampled in 3 localities (Bogo, Gazawa and Kaélé). The results show that the grey color (80.02%) is dominant while white (4.85%) is least represented. Majority of the donkeys display the St. Andrew cross (84.50%) and not zebra lines (76.20%). The mean body measurements assessed (cm) were as follows: thoracic: 108.31 ± 6.82, height at withers: 98.05 ± 6.88, trunk length: 101.37 ± 13.07, neck length: 40.47 ± 8.79, right ear length: 25.09 ± 1.24, length of the left ear: 25.43 ± 1.07 and adult live weight: 122.11 ± 1.24 kg. The effect of sex on biometric measurements and indices was not significant (P≤0.05) however females were heavier (124.72 ± 1.65kg) than males (120.44 ± 1 .79 kg). The average height at withers of Gazawa’s animals was significantly higher (P>0.05) than those from the other localities. Compactness, body profile and mass indexes were significantly high (P ≤ 0.05) in Bogo and Kaélé. The body and profile indexes were significantly higher in Gazawa compared to the other two localities. The correlations were significant (P ≤0.01), positive and perfect between live weight and thoracic circumference (r = 1.00) both in males and females. The linear type equation (LW= -155, 50 + 2,565PT) better predicts the body weight (R2 =1, 00). The corporal profile index (CPI: 0.98 ± 0.01) and the relative corporal index (RCI: 0.93 ± 0.01) made it possible to classify the donkeys of the Sudano-Sahelian zone as of longiline profiles (RCI≥0, 90) for Gazawa and medians (0.84≤RCI≤0.90) for animals of the other localities (Bogo, kaélé). The genetic diversity of the donkey obtained by the principal component analysis (PCA) revealed that live weight, trunk length and thoracic circumference contribute to 62.17% of the genetic variability in the population. The discriminant factorial analysis (DFA) shows that the population consists of 3 genetic types as indicated by the phylogenetic tree. The observed diversity leads to the conclusion that there are opportunities for genetic improvement of donkey population from the Sudano Sahelian zone of Cameroon.

Keywords: Biodiversity, morphobiometry, donkey, Sudano-Sahelian zone, Cameroon