PSI-3 Effect of stage of maturity of forage pea cultivar (Pisium sativum L.) in hay on palatability, ruminal fermentation, and digestibility when fed to beef cattle

Abstract

Abstract The objective of this experiment was to evaluate stage of maturity at harvest for pea hay on DMI, eating behavior, ruminal fermentation, and digestibility when fed to beef heifers. Pea hay was harvested at early, mid, and late stages of maturity. Early was defined as observing flat pods at one or more nodes. Mid stage was defined as seeds filling the pods at one or more nodes and leaves beginning to turn from green to gold. Late stage was defined as yellow, dry seeds filling pods on most or all of the nodes, with a yellow color to the leaves and pods. Six ruminally-cannulated Speckle Park heifers were used in a replicated 3 × 3 Latin square design with 3 18-d periods with pea hay included at 40% of the dietary DM. Stage of maturity did not affect DMI or ruminal total SCFA concentration with averages of 3.2 kg/d and 96.55 mM, respectively. Time spent ruminating decreased with advancing maturity when reported as min/d, min/kg DMI, and min/kg NDF (P ≤ 0.01). Mean ruminal pH also decreased with advancing pea maturity (P < 0.01). The ruminal DM and uNDFOM pools were not affected by stage maturity (P ≥ 0.55). While the rate of digestion for NDF was not affected, NDF passage rate decreased by 0.21 %/h with advancing maturity (P = 0.02). Apparent total tract digestibility of NDF (average = 16.30%, P = 0.41) was not affected but starch digestibility tended to decrease from 96.10 to 93.08% with advancing maturity (P = 0.07). Overall, stage of maturity at harvest for pea hay does not appear to impact DMI, fermentation, or digestibility.