Investigation into the durability of washed rice straw for equine bedding and the repetitive use of washing water

The present experiment investigated durability during the repetitive use of washed rice straw, as bedding material, and washing water as a model study. Residual nitrogen levels, elasticity, and water suction rates for washed rice straw‐adhered urea were measured. In addition, outflow levels of nitrogen and mineral ions (Na⁺, NO₂^‐ + NO₃^‐, SO₄^2?, PO₄^3?, Cl^‐) for washing water were measured to determine durability. Nitrogen levels of rice straw significantly (P < 0.05) decreased after two washings. There was no significant change in elasticity of repetitively used rice straw. Suction rates of rice straw after the second and third washings increased significantly (P < 0.05) compared to the first time. With regard to the number of washings, the mineral ion outflow level in the washing water for nitrogen, Na⁺, NO₂^‐ + NO₃^‐ and PO₄^3? after each washing was not significant. However, nitrogen outflow level tended to decrease after the third washing. SO₄^‐ and Cl^‐ did significantly decrease (P < 0.05) with the number of washings. In this study, it was considered that rice straw and washing water could be used repetitively three times. Furthermore, in order to maintain effluent standards, washing water from the first washing needs to be processed in a septic tank.     

Effects of cecectomy on digestion and retention time of digesta in rats

The present experiment aimed to obtain basic knowledge of the role of the cecum in the digestion of protein, fiber and energy, and in the retention of digesta in rats. Twelve healthy male Sprague–Dawley strain rats were used. The experiment lasted for 8 weeks following preliminary feeding. Crude protein [CP], acid detergent fiber [ADF], and energy digestibilities were measured in weeks 1, 4, and 7 of the experiment, while the digesta retention time was measured in weeks 2, 5, and 8. At the end of the test, the colon capacity was measured after killing the rats with diethyl ether. The effects of the cecectomy were not recognized in bodyweight gain, even while the feed intake was high and the feed efficiency was low due to the cecectomy. However these effects were not recognized in the latter half of the test periods. The mean retention time of digesta for the cecectomized rats was about 2 h shorter than that for the control group of rats, while the retention time of digesta in week 8 increased compared to weeks 2 and 5. The digestibility of each substance was significantly lower following the cecectomy. The colon became swollen because of the cecectomy and this swollen colon made up for the capacity of the dissected cecum. It had been considered that the cecum does not play a role in the digestion of nutrition for growth, however, the present results showed two types of effects of cecectomy: one that disappears in accordance with time after surgery (i.e. feed intake and feed efficiency), and another that continues for a longer period (i.e. digestibility, retention time of digesta).