| dc.description.abstract | In the framework of collecting information that will aid in development of breeding and
conservation strategies and policies intended for the conservation of indigenous Tswana sheep in
the Southern part of Botswana, a survey of production system and on-farm phenotypic
characterization of indigenous Tswana sheep were undertaken in the Kgatleng, Kweneng, SouthEast and Southern districts. Multi-stage purposive and random sampling were employed as
sampling techniques. Detailed structured questionnaires on farmers’ socio-economic parameters,
breeding and general management practices on Tswana sheep, field observations of animals, body
measurements and secondary data collection were used to produce the data. Data on qualitative
characters and quantitative measurements were made on 665 sheep stratified by dentition into four
age categories of zero permanent pair of incisors (0PPI), one permanent pair of incisors (1PPI),
two permanent pairs of incisors (2PPI) and three or more permanent pairs of incisors (≥3PPI) to
represent age ranges of 6-11, 12–24, 25–36 and above 36 months, respectively. Qualitative survey
data were analyzed using procedure frequencies of Statistical Package for Social Sciences while
quantitative data were analyzed using Statistical Analysis System. Results revealed that the mean
average flock sizes for Kgatleng, Kweneng, Southern and South-East were 22.20±3.8, 24.81±3.56,
30.08±3.77 and 23.58±3.77, respectively. Sheep played multifaceted roles for farmers across
districts. Amongst the reasons for keeping sheep, Kgatleng and Kweneng district farmers primarily
kept sheep for generating cash derived from sales (index= 0.480 and 0.390, respectively) and in
the Southern and South-East districts farmers primarily kept sheep for ceremonial (socio-cultural)
use (index=0.310 and 0.371, respectively). Competitive superiority of indigenous Tswana rams
over their exotic counterparts in terms of survival and reproduction under Botswana environment
was the most preferred trait when selecting breeding rams in Kgatleng ( index= 0.290), Kweneng
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(index= 0.301) and South-East ( index= 0.247) while in Southern district breeding rams were
mainly selected based on body size (index= 0.372). Castration of rams in Kgatleng, Kweneng and
South-East districts was mostly done at 3-6 months while Southern district farmers castrated at a
later age of 6-12 months.
The dominant coat color pattern on Tswana sheep was plain with most sheep having white
dominant and plain white color coats. Most Tswana sheep had a characteristic feature of short fat
tail with a straight tip, no wattles, no horns and almost all sheep (98.65%) had horizontal ear
orientation. District, sex and age and the age by sex interaction had a significant (P<0.05) effect
on body weight and most linear body measurements. The body weight and most linear body
measurements of sheep increased gradually as the sheep advancement in age. Tswana males were
generally heavier and superior than females in most linear body measurements. Indigenous Tswana
sheep from the Southern district showed superiority in some features of economic importance such
as body weight, body length and heart girth over other districts. The overall mean body weight,
heart girth, body length, wither height, rump width, ear length, tail length, tail circumference, head
length, head width, shoulder width, cannon bone length, cannon bone circumference, neck length,
rump length, rump height and scrotum circumference (in males) across districts were 35.93±0.55
kg, 78.31±0.65, 62.17±0.53, 64.51±0.51, 15.98±0.20, 11.43±0.12, 21.67±0.63, 12.54±0.57,
13.15±0.13, 10.00±0.11, 21.79±0.33, 15.19±0.12, 7.51±0.52, 30.38±0.43, 23.56±0.28, 64.44±0.31
and 26.66±0.89 cm, respectively.
There were positive and significant correlations observed between body weight and most linear
body measurements for both sexes. The highest correlation coefficient was found between body
weight and heart girth for both sexes of Tswana sheep. The regression analysis to predict body
weight from linear body measurements indicated that body weight prediction could be more
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accurate when more than one independent variable was used. However, from a practical view
point, the use of heart girth as a sole predictor for body weight was suggested since heart girth
accounted for more variability than other linear body measurements for sexes and also due to its
ease of measurement under farmers’ conditions. The prediction of body weight for Tswana sheep
was therefore based on the regression equations y= -64.15+1.28x in males and y= -53.47+1.14x
for females where, x and y are heart girth and body weight respectively. This study reveals
existence of diversity of sheep genetic resources across districts which needs to be verified at a
molecular level. | en_US |
