2.4. Sample size and sampling
The minimum sample size (n) required was determined according to
Thrusfield (2007) using 95% level of confidence, the prevalence of
66.1% (Adelakun and Akande, 2018) and desired absolute precision of
5%. i.e. n = Z2 p (1-p)/d2 = 345
cattle. However, 377 cattle were examined to increase precision.
Cattle were selected randomly from 39 different herds across the two
LGAs, the herds were grouped into three; 0-30, 31-50 and
>50 based on the herd size. The average number of cattle
per herd is 48, an average of 20% of each herd was sampled. The maximum
herd size screened was 89 while the least sampled was 29.