Grazing Bites per Day of Goats on Some Tropical Grass Pastures and the Influence of Sward Characteristics

The number of grazing bites per day of Japanese Saanen goats was measured on 3 species of tropical grass pastures, fingergrass (Digitaria adscendens H.B.K. Henry), Rhodesgrass (Chloris gayana Kunth) and green panic (Panicum maximum Jacq. var. trichoglume Eyles). In addition, green panic pasture at different stages of growth (vegetative, booting, heading and mature) was used to examine the relations of the grazing bites to structural measures (plant height, herbage yield per unit area and cell wall components) and nutritive measures (crude protein, in vitro dry matter digestibility and digestible energy) of the pasture. The number of grazing bites varied among species or growth stages of the pasture, ranging from 46,200 to 95,100. The grazing bites in the mature stage of the pastures tended to be higher than those in other growth stages. The grazing bites were positively correlated with the structural measures of green panic and negatively correlated with the nutritive measures. Especially herbage mass had a close association with the grazing bites, being expressed by quadratic regression (R²=0.905). The results obtained indicate that sward structural and nutritive characteristics affect the daily grazing bites.