Evaluation of Stockpiled Perennial Forage Compared to Grass-legume Hay for Chemical Composition and Rumen Degradation Kinetics

The objective of this study was to determine the chemical composition and in situ degradability dry matter (DM), crude protein (CP), acid detergent fiber (ADF), neutral (NDF) stockpiled perennial forage (SPF) or sun-cured hay (HAY) when collected at start end (October vs. December) fall grazing. Selected 6, 4-ha paddocks consisting meadow bromegrass alfalfa, were randomly assigned 1 2 replicated (n = 3) winter feeding systems (SPF HAY). Sampling done twice per year beginning (October) (December) from (a) field (b) harvested round bale over consecutive years. two (n=3) HAY (n=3)). SPF To evaluate degradability, duplicate nylon bags each experimental unit incubated for 0, 3, 10, 13, 25, 48, 72, 96 h five Hereford heifers fitted with rumen cannula. Relative HAY, had greater (p 0.01) OM (906 916 g/kg DM) NDF (653 631 concentrations. date no effect > 0.05) on CP, OM, ADF both forages, whereas forages sampled December. soluble fraction (S) DM October, December s (156, 138, 152 DM, respectively) relative (106 DM). potentially degradable (D) CP less < samples compared October (257 522 523 respectively). a (749 587 ADF) (770 591 NDF) HAY. type sampling did not affect effective NDF. Regardless decreased (SPF: 770 730 (HAY: 680 491 NDF). These findings suggest grazing is robust substitute beef cows.