Effect of lactation feeding level on the performance and subsequent production of indigenous pigs in Nigeria.

A total of 72 indigenous Nigerian sows with a live weight varying about 103 (+/- 6) kg on the 110th day of farrowing depending on feeding level was used to determine an optimum restrictive feeding level during the first lactation, 55 of which were also investigated in the following lactation under comparable conditions. During their 42-day lactation period the sows were fed 0.3 or 0.5 kg of a maize-groundnut-cake mixed feed (15% CP) per nursing piglet or ad libitum. The reduced overall feed intake of the sows (72.6 and 126.4 as compared with 164.6 kg) or per weaned piglet (13.8, 20.1, and 25.7 kg) led to different live weight losses of these lactating sows (27.7 and 18.8 as compared to 19.6 kg), significantly different litter size on the 21st and 42nd day of age of the litter, to a differentiated proportion of weaned animals, and to different weaning weights. Restricting the sow feed to 0.3 kg per nursing pig reduced the live weight of the sows on the 110th day of the second farrowing, the number and weight of pigs born alive as compared with the other feeding variants, but it did not effect the vigour of the pigs born alive at the second farrowing.

Growth and sexual development of indigenous West African boars.

60 indigenous West African boars were slaughtered in groups of five each per month at ages from one to twelve months, and the body weights and the weights of several parts of the reproductive tract were determined. It was found that the growth rate of the reproductive organs is not uniform throughout these twelve months. Up to the fourth month there was a lower growth rate, followed by a strong increase up to the sixth month, and finally a slower growth period up to twelve months of age. The growth rates of the testes and epididymides correlated with the body growth rates, strongly between the testes and the body weight in the first four months, between epididymides and body weight in the fifth and sixth months, between testes/epididymides and body weight from the seventh to the ninth month, and after that until the twelfth month between testes/vesicular glands and body weight.

The influence of season on sow weaning to estrus interval and subsequent reproductive performance following estrus synchronization by batch weaning.

In 45 indigenous Nigerian sows, which had been synchronized in their estrous cycle by batch weaning, the interval was investigated from weaning to estrus in the rainy and dry seasons. It was found to be 3 1/2 days in each season. The heat was short, especially the standing estrus, which will have to be investigated further. There was no seasonal difference in the number of piglets weaned per sow. In the dry season, sows farrowing lost more weight from birth to weaning than in the rainy season. Sows farrowing into the rainy season delivered more piglets.

The influence of season, parity, and duration of lactation on some performance traits of sows indigenous to Nigeria.

120 young sows of less than one year of age and 240 old sows indigenous to Nigeria were randomly subjected to a 2 X 2 X 2 factorial analysis of variance. The results showed that the factors season, parity, and lactation period had no influence on the gestation period and some weaning features, like the number of stillborn piglets per litter and pre-weaning deaths. More piglets were farrowed live by old sows than by the young sows. The litter birth weight, the number of piglets weaned per litter and the number of days to estrous following weaning depended on the season and the lactation length.