Abstract
Six heifers (1/4 Brahman × 1/4 Jersey × 1/2 Angus, 290 kg average weight) with ruminal, duodenal and ileal cannulae given ad libitum access to corn silage with or without 100 mg monen-sin·head−1 ·d−1 were used to determine interrelationships among behavior, ruminal motility and intake. Voluntary intake was positively related (P<.001) to eating time, duration of the main morning meal and daily mastication time. Intake was negatively related to unitary times [min.g dry matter−1 ·(kg body weight.75) −1] of eating (P<.05), rumination (P<.001), mastication (P<.001), unitary number of rumination boli (P<.001), and latency time between termination of morning meal and onset of rumination (P<.05). Both daily and unitary eating and ruminating time were positively related (P<.001) to daily and unitary mastication time and unitary number of strong craniodorsal ruminal contractions. Positive relationships (P<.01) were found between mean duration of daily meals, main evening meal and unitary eating time, and between mean duration of rumination periods and unitary ruminating time. Daily and unitary number of rumination boli and mean duration of one bolus were positively related (P<.01) to unitary ruminating time. Interrelationships between intake, eating and ruminating activities and associated cranio-dorsal ruminal motility were all influenced (P<.01) by individual heifer, which indicates potential in identifying individuals with better than average mastication behavior and ruminal motility. Results are interpreted to suggest that fast eaters and fast-efficient-ruminators appear to have highest intake capabilities. Copyright © 1987. American Society of Animal Science . Copyright 1987 by American Society of Animal Science.