Morphometrical characterization and structural indices of indigenous Tswana sheep subpopulations in Botswana: a prerequisite towards accurate type classification of indigenous Tswana sheep

Abstract

This study was conducted to describe indigenous Tswana sheep subpopulations based on morphometric traits and structural indices. Data on qualitative and quantitative traits were made on 1330 sheep of both sexes aged 1–3 years in southern and central AEZ. Fourteen structural indices were calculated from individual animal morphometric trait measurements. The data were analyzed using Statistical Analysis System. Tswana sheep subpopulations significantly (p<0.05) varied in coat colour type, head and back profiles while other traits did not differ. Most sheep have a plain coat colour pattern (64.4%), multicoloured (48.5%), with the dominant traits being white skin coats, short fat tails with a thin tip, straight heads and back, semi-pendulous ears and polled. There was sexual dimorphism across subpopulations with rams exhibiting higher morphometric values than ewes, except Botswana University of Agriculture and Natural Resources flock. The National Agricultural Research and Development Institute flock had significantly (p<0.05) higher biometric traits than their counterparts. Structural indices indicated that Tswana sheep are well balanced (body ratio: 1.00), with good thoracic development (>2.1) and rectangular (proportionality: 100). This indicates fitness, good respiratory adaptation and inclination of Tswana sheep towards meat-type aptitude. This study provides information key information for designing genetic improvement and conservation programmes for the sustainable utilization of indigenous sheep.