Effects of fertiliser nitrogen and herbage dry-matter content on herbage intake and digestibility in bullocks

Abstract

SUMMARY 1. Two experiments were conducted, the first during May, July and August, 1958, and the second during August 1960. The first experiment measured the intake and digestive efficiency of cattle fed on fresh cut herbage from low-and high-nitrogen manuring treatments with and without irrigation. The second experiment tested the effect of water added to fresh cut herbage on the intake of cattle. 2. Rainfall during the summer of the first experiment was high and irrigation had no effect on any of the criteria used. 3. Although the dry-matter content of the fresh herbage from the high nitrogen treatment was consistently lower than that from the low nitrogen treatment (16·6% compared with 19·7% on average when free of surface moisture) the dry-matter intake was the same at 1·97 lb. dry matter per 100 lb. live-weight, on both herbages. 4. The average digestibility of the high and low nitrogen treated herbage was 77·6% and 75·4%, the difference being significant. No scouring occurred. Digestibility was 78·9% in May, 76·1% in July and 74·5% in August (average of N levels). 5. Rain water carried on the leaf surface was shown to have no effect on dry-matter intake. 6. It is concluded that the dry-matter intake of cattle feeding on fresh herbage is unlikely to be restricted either by a high internal water content in the herbage or by rain water on the leaf surface.