Analysis of a Japanese Black Cattle‐rearing system utilizing a bahiagrass (Paspalum notatum Flügge) pasture: 3. Intake from pasture

Abstract A Japanese Black Cattle‐rearing system utilizing a bahiagrass (Paspalum notatum Flügge) pasture in coastal Miyazaki, southern Japan, was analyzed in terms of intake from pasture. In a field approach, herbage intake by grazing cattle was measured for nine periods (1–5 days) during a grazing season (May–October) along with some other variables (e.g. air temperature, herbage mass, digestibility of grazed herbage), under varying levels of supplementary feeding. The intake from the pasture was most closely related to the intake of supplement, showing a negative linear response at a substitution rate of 0.736–0.750. The intake under no supplementation, i.e. a maximum intake from the pasture, was lower than the voluntary intake predicted with feeding standards. In a modeling approach, a semi‐mechanistic model for predicting grazing intake was developed using information from the literature as well as the field data. The performance of the model was acceptable. The model showed similar substitution rates (0.64–0.69), and considerable intake restriction (nearly 30%) that is not attributable to limitations by herbage mass, herbage allowance, diet digestibility or air temperature. The results indicate that a low maximal intake by the animals due to low grazing motivation is a major characteristic of the system where supplementation is a usual management practice.