The Influence of Wetting on the Composition of Alfalfa, Red Clover, and Birdsfoot Trefoil Hay1

Abstract

AbstractField cured hay is subject to yield and quality loss due to leaching, mechanical loss, and respiration. The objective of this study was to measure changes in chemical composition and in vitro dry matter disappearance (IVDMD) of alfalfa (Medicago sativa L.), red clover (Trifolium pratense L.), and birdsfoot trefoil (Lotus corniculatus L.) in response to wetting during hay curing.Treatments included: (1) a control collected 96 hours after clipping (96 hour), (2) wetted after 48 hours of drying and collected 48 hours later (wet 48 hour), and (3) wetted both 24 and 48 hours after clipping and collected 48 hours later. Separate samples of each species were collected and dried immediately after clipping. Each treatment was replicated five times. Plants were grown in Plano silt loam (fine‐silty, mixed, mesic Typic Argiudoll) soil. Samples were analyzed for leaf percentage, N, IVDMD, neutral detergent fiber (NDF), acid detergent fiber (ADF), lignin, total nonstructural carbohydrate (TNC), total sugars, starch, and reducing sugars.Wetting twice reduced alfalfa leaf percentage from 54.0 to 45.6%. The same treatment increased N concentration in alfalfa and red clover by the equivalent of 2.7 and 2.9 percentage units of crude protein, respectively. Such an increase may be due to greater losses of other plant constituents. Wetting twice reduced TNC concentration by 34, 67, and 37% for alfalfa, red clover, and birdsfoot trefoil, respectively. Neutral detergent fiber concentration increased by 6.1, 10.8, and 9.8 percentage units by wetting twice compared with the unwetted control for alfalfa, red clover, and birdsfoot trefoil, respectively. The increase in forage NDF concentration due to wetting suggests that leaching might reduce the intake potential of the forage and thus reduce animal productivity. Wetting twice significantly reduced IVDMD of red clover and birdsfoot trefoil but not alfalfa. Results of this study indicate that quality losses due to wetting during hay curing are significant and that legume species differ in their response to wetting.