養豚飼料の粒度が消化率とふんの性状に及ぼす影響

In order to investigate the effects of grain sizes of swine feeds upon their digestibility and properties of feces, 3 classes of feeds with the same composition but different grain sizes and a high-energy feed were prepared for the digestibility test as well as other tests. The 3 different groups were the large particles which passed through the sieve for the feed of mature poultry, the moderate particles (which was of the size of so-called Kanagawa Prefectural Authorized size No. 4 for Swine), and the fine particles (which passed through the sieve for later stage of creep feed). The highenergy feed was prepared by adding 5.2% of yellow grease.<br>1. The amount of excreta increased as the grain sizes were larger. The excretion rate against the ingested feed amount was also higher as the grain sizes were larger. The amounts of drinking water and urination varied very much with individual pigs, showing no significant difference by the grain sizes, but the correlation between the two amounts was extremely deep (r=0.974).<br>2. The digestibility of each feed component varied considerably with the grain sizes. The digestibility of each component tended to be better as the grain size became smaller. The trend was even more distinct particularly with the crude fibers. The difference in digestibility was smaller between the group of fine particles and that of moderate particles than the one between the moderate particles and the large particles. This meant that the grain size of the large particle group was excessive from the viewpoint of digestibility and utility of swine feed.<br>3. Gross findings of feces were that those with fine particles and moderate particles had smooth surface and solid appearance with distinct lump shape, whereas that of the large particle group had many large hulls of corn grains and was fragile and easily disintegrated by the exogenous pressure. The properties of feces of the group with addition of yellow grease were similar to those of the large particle group, which was very much different from the findings with the commercial feeds with addition of oils and fats. This difference may be attributed to the difference in the grain sizes of the basic feed.<br>4. Hardly any differences were noted in the changes by time lapse of the feces in water between the group with fine particles and the group with moderate particles. Both groups maintained their original shapes even after 2-4 hours, but the grnups of large particles and the yellow grease addition group were mostly disintegrated with stirring at 30 minutes<br>5. with respect to the distribution of particle sizes and separation rate by sieving of undigested solid matters in the feces, the particle sizes of the undigested matters found in feces tended to be larger in proportion to the grain sizes and the sieving rate tended to be higher.<br>Particularly, most of the hulls of corn grains were excreted with no changes in the group with larger grain size, and it could be assumed that the large grains would have affected the shapes and properties of feces in this group.