INFLUENCE OF IN SITU BAG RINSING TECHNIQUE ON DETERMINATION OF DRY-MATTER DISAPPEARANCE

Acceptable mechanical in situ bag rinsing methodology should reduce error variance and labor requirements over hand-washing techniques. Objectives of this study were 1) to compare fixed-time hand rinsing to fixed-time machine rinsing, 2) to evaluate effects of length of machine rinsing, and 3) to evaluate effects of numbers of bags simultaneously rinsed on DM remaining, DM disappearance, and their SE. Lower DM remaining, higher DM disappearance, and higher SE for DM remaining and DM disappearance were observed when bags were machine rinsed twice for 5 min than when bags were either machine rinsed twice for 2 min or hand rinsed. Machine rinsing twice for 2 min or hand rinsing bags resulted in similar SE. Hand-rinsed bags had higher DM remaining than bags machine rinsed twice for 2 min, but differences were small (38.84 and 37.92%, for bags hand rinsed or machine rinsed 2 min, respectively). There was little difference between DM remaining of bags machine rinsed twice for 1.0, 1.5, or 2 min. Rinsing 50, 100, or 200 bags simultaneously had little effect on DM remaining or SE, Machine rinsing bags used for in situ DM digestibility studies (up to 200) is an acceptable alternative to hand rinsing and also reduces manual labor requirements. © 1990, American Dairy Science Association. All rights reserved.