Abstract
In order to prevent the delay of growth of growing-finishing pigs in winter, the influences of the increase in the amount and calory of feed, higher nutritional levels of feed, heating of pigpens and cold environments upon the rate of digestion of feed by swine were investigated in the present study.
1) The growth and weight gain were improved by the increase in the amount of feed, and growth, weight gain and feed conversion rate were improved by heating the pigpens. In the cold environments, the days required for the growing-finishing could be reduced by increasing the amount of feed by 20%, but there were hardly any differences in the feed conversion rate by the 20% increase. No adverse effects were observed by the increase in the amount of feed upon the results of slaughter or morphology or quality of carcass.
2) The growth and weight gain were improved by raising the calory of feed, and the feed conversion rate was also improved, but there were hardly any differences in the TDN required for gaining 1kg of weight in cold environments. Oils and fats of animal origin which were added for raising calory made the quality of meat poorer (especially that of the fat).
3) Higher nutritional levels of feed could improve both the weight gain and feed conversion rate, and required less TDN and DCP for weight gain of 1kg even in cold enviroments than otherwise.
4) The cold environments exerted no adverse effects upon the digestibility of feed except that of crude fibers, nor was there any difference caused in the nutritional value of feed by the cold envitronments.
