Daily Herbage Digestibility Under Rotational and Strip Grazing

Abstract

Fecal concentrations of plant pigments were used as indices of pasture digestibility by cows rotationally and daily strip grazing alfalfa - bromegrass pasture (Medicago falcata and Bromus inermis) in 1957. Comparison of digestibility data from daily and 3-day composite fecal samples revealed that the 3-day samples corresponded best with the middle day represented in each sample. Further statistical analysis showed significantly higher partial correlations of milk production and digestibility independent of the linear effects of time using data from 3-day rather than from daily samples. Milk production was significantly related to time, live weight and digestibility under rotational grazing. Although production was also related significantly to all 3 variables under strip grazing, the addition of digestibility did not improve the multiple correlation of milk production, time, and live weight.