Effects of addition of water-filled bladders or volatile fatty acids into the rumen on digesta passage in the dairy cow eating ad libitum

Abstract

The effects of 2 satiation tests on feed intake pattern (Faverdin et al, 1992) and on digesta passage (this trial) were studied. Four rumen-fistulated cows in mid-lactation (27 kg milk) were successively assigned to 3 treatments: control, VFA infusion and insertion of a 20-1 water-filled bladder (WFB) in the rumen. Each period lasted for 14 d. A pelleted diet (60% dehydrated maize, 30% concentrate, 10% hay) was offered ad libitum once daily. Rumen liquid turnover rate (KI) and volume (vol) were estimated by PEG dilution. Mean retention time (MRT) in the digestive tract of maize particles labelled with Eu was calculated from the quantities (m) of marker excreted in faeces (5m,Retention time of small particles in the rumen (RT) was calculated from the descending part of the curve.