Performance of goats and sheep under communal grazing in Botswana using various growth measures

Abstract

We conducted a survey to evaluate the growth of goats and sheep under communal grazing, and to determine the relationship between weight, heart girth, shoulder height, and body condition score in Kweneng, Central and Kgalagadi districts, Botswana. The same animals were measured on two separate occasions, approximately one month apart, to allow growth rates to be recorded. Significant differences in growth rates between the three case study districts were found for both goats and sheep. Amongst the goats measured, gains in height and weight were significantly greater in the Kweneng district, while gains in heart girth measurement were greatest in the Central district. In the case of sheep, weight gain was significantly higher in the Central and Kgalagadi districts, increases in girth measurement were significantly higher in the Central district, and shoulder height gain was significantly greater in the Kweneng district. Statistical tests were used to determine the relationships between animal weight and the other measures taken for goats and sheep. Heart girth in both goats and sheep was shown to be a significant predictor of weight across all three districts. Likewise, shoulder height proved to be a statistically significant predictor of animal weight for both goats and sheep, across each district. The data therefore suggest that heart girth and shoulder height have potential to act as proxy measurements of weight in both goats and sheep, potentially providing smallholder farmers with a cost-effective way of estimating small-stock productivity.