干旱区生态环境知识资源中心

Herd dynamics of indigenous pigs were determined in a semi-arid farming area of Chirumanzu, Zimbabwe. Thirty-two pig herds were monitored once every month for 12 months. Consequently, pig production potential (PPP) and pig production efficiency (PPE) were computed for each month. Incidences of farrowing were higher in times of pig confinement (57%) than in times when the pigs were free ranging (43%). About 23% of the farmers interviewed had access to irrigation. The mean pig herd size per household was 3.3. The average litter size per farrowing was 7.7. Pigs were free ranging for most of the year and penned during the rainy season. Herd sizes changed with month (P < 0.05). Farmers who had access to irrigation had higher (P < 0.05) herd sizes, number of piglets and the number of adult pigs. Highest piglet numbers were observed during the rainy months. The number of mature pigs contributing to pig production efficiency was low. Piglet mortality was the major cause of exits from the herd and was higher in farmers with no access to irrigation facility (P < 0.05). The PPP was highest in farmers who had access to irrigation (P < 0.05), except in June and July. The PPE was low and not affected by either month, village or access to irrigation (P > 0.05). It can be concluded that pig production efficiencies were low and intervention strategies to improve them need to be developed.