Reproduction of pigs in the hills of eastern Nepal.

A survey of 101 farmers with sows was conducted in the Koshi Hills of Nepal. Estimates of those reproductive traits which did not differ significantly between local and Pakhribas crossbred sows, are farrowing interval 7.4 months, litter size at birth 8.3, age of piglets at weaning 2.2 months and total number of farrowings 13.2. Local pigs reach sexual maturity sooner than Pakhribas crossbreds; age at first farrowing for the two genotypes is 10.7 and 12.0 months (P < 0.05), and age at first mating of boars is 6.5 and 7.4 months (P < 0.05). Sows farrow throughout the year and there is no clearly defined best season for farrowing. Pre-weaning mortality rates are estimated to be 22% for local piglets and 15% for Pakhribas crossbreds. Almost all farmers practise controlled mating in which either the sow is taken to the boar or the boar is brought to the sow. The proportion of farmers (with sows) who own a boar is only about 5 per cent.