Abstract
In order to evaluate the effects of water supply restriction in summer upon the growth of swine, comparative studies were conducted on the consumed volumes of drinking water, weight gains, amounts of ingested feedstuffs, and results of performances based on findings upon slaughter after rearing for 11-12 weeks 8 each of W and LH which were divided into two groups of the free water drinking group and the restricted water supply groups of 50% (Experiment 1) and 70% (Experiment 2) from that of the basic amount. The following results were obtained.
1. The mean ratios of the amounts of drinking water to the body weights during the test period in the free water drinking group were 13.4% and 17.6% in Experiments 1 and 2, respectively. The actual amounts of drinking water in the restricted water supply group were 7.0% and 4.2% in Experiments 1 and 2, respectively, by which it was found out that the target amounts were approximately consumed, showing significant difference from the counterparts in the free water drinking group. (p<0.01).
2. The weight gains with restriction of the amounts of drinking water into 50% and 70% decreased into 82.3% and 76.3% of that of the free water drinking group, respectively.
3. The amounts of ingested feedstuff were reduced into 85.2% and 79.8% of that of free water drinking group when drinking water was restricted into 50% and 70%, respectively.
4. The mean weights, lengths and hack loin lengths II of the carcass of the animals in the restricted drinking water supply groups tended to be smaller than those of the free water drinking group, while the dressed carcass percentage of the restricted water supply groups tended to be slightly higher than those of the latter group, but there was no difference seen between the two groups in terms of the ratios of ham and thickness of back fat.
