Effects of rate and amount of propionic acid infused into the rumen on feeding behavior of Holstein cows in the postpartum period

摘要

The objective of this study was to determine theeffects of 2 amounts of propionic acid (PA) infusedintraruminally at 2 rates of infusion at the initiation ofmeals on the feeding behavior of Holstein cows in thepostpartum period. We hypothesized that the amountand length of time of infusions would interact to affectfeeding behavior: rapid infusion of a higher dose ofPA would result in larger meal size with greater timebetween meals compared with a slower rate, whereasfaster infusion of a lower dose of PA would reducemeal size and the time between meals compared with aslower infusion of the same dose. Eight ruminally cannulated,multiparous Holstein cows were used in a 4 ×4 Latin square design experiment. Cows were blockedby parturition date and randomly assigned to treatmentsequence within square. Treatments were infusionof 2.5 L of 0.5 M (HI) or 0.2 M (LO) solutions ofPA at initiation of meals over 5 min (FST) or 15 min(SLW) for 12 h following feed delivery. Contrary to ourhypothesis, no interaction between amount and rate ofinfusion was detected for any feeding behavior parametermeasured. The FST treatments did not affect drymatter intake or metabolizable energy intake comparedwith SLW. The FST treatments tended to increasemeal length compared with SLW (28.1 vs. 22.7) butdid not affect meal size. The FST treatments tended todecrease total eating time (108 vs. 122 min/12 h) butdid not affect meal frequency compared with SLW. TheHI treatments decreased dry matter intake (7.4 vs. 11.5kg/12 h) and total metabolizable energy intake (22.5vs. 29.1 Mcal/12 h) compared with LO by decreasingmeal frequency (5.8 vs. 7.5 meals/12 h). The HI treatmentsdecreased eating time (103 vs. 127 min/12 h)compared with LO but did not affect meal size. Furtherresearch is warranted on the effects of the temporalsupply of propionate on propionate metabolism andfeeding behavior.