Feed Quality of Hay Containing Perennial Broadleaf Weeds1

Abstract

AbstractMany studies have been conducted to determine how to control perennial broadleaf weeds in alfalfa (Medicago sativa L.) swards, but little information is available on the effects of these weeds on forage utilization by ruminant animals. Therefore, alfalfa or alfalfa‐grass mixtures infested with yellow rocket (Barbarea vulgaris R. Br.), white cockle (Lychnis alba Mill.), and dandelion (Taraxacum officinale Weber.) were treated with herbicides to provide differences in weed composition of harvested forage. Differences in intake, digestibility, and nutrituve value index between weedy and weed‐free forages were determined by feeding hay from the various herbicide treatments to goats in stall trials. Observations indicated that dandelion and white cockle were palatable and yellow rocket was unpalatable.Animal intake, in vivo digestibility, and nutritive value index werereduced by an infestation of yellow rocket but not by white cockle in alfalfa‐grass mixtures. Crude protein concentration and in vitro digestibility were highest in dandelion, intermediate in white cockle, and lowest in yellow rocket. Based on the small differences in quality observed between most of the weedy and weed‐free forages, we concluded that only yellow rocket would reduce the feed value of hay for ruminant animals.