THE EFFECT OF NUTRIENT COMPOSITION ON THE VOLUNTARY INTAKE AND APPARENT DIGESTIBILITY OF FIRST- AND SECOND-CUT GRASS HAYS PREPARED IN PRINCE EDWARD ISLAND

Abstract

Hays prepared in Prince Edward Island from the primary growths of Rise reed canarygrass, Tardus orchardgrass, Saratoga bromegrass, Itasca timothy, and Trader meadow fescue cut in mid- to late June, and from their regrowths cut 7–8 wk later, were studied for the interrelationships among cell wall components, in vitro dry matter disappearance values, and in vivo determined values of voluntary intake of digestible energy (DEI) and apparent dry matter digestibility (DMD). The in vivo values for each hay were measured on four wether lambs during a 24-day feeding trial. Simple correlation coefficients were calculated among neutral (NDF) and acid detergent fibers (ADF), lignification (= log10 (lignin/ADF)), two-stage in vitro dry matter disappearance (IVDMD), acid-pepsin solubility (APDMD), DEI, and DMD. The content of NDF was not correlated with either DEI or DMD value for the first-cut and second-cut hays (P > 0.10). First-cut hays showed correlations between lignification and DMD (r = −0.88, P < 0.05) and between APDMD and DEI (r = 0.87, P < 0.10). Second-cut hays indicated the following correlations: ADF with DMD (r = −0.98, P < 0.01), and IVDMD with both DMD (r = 0.97, P < 0.01) and DEI (r = 0.95, P < 0.05). Lignification showed promise as a predictor of DMD and APDMD could predict DEI for the first-cut hays prepared in this region. In the case of second-cut hays, the ADF or IVDMD could predict DMD, whereas APDMD or IVDMD may prove useful in predicting the DEI value of local hays.