Ingestive and masticative behaviour is of importance to our understanding of the physiology of nutrition, the feeding of ruminants, including feed intake, diet selection, feed preparation and technology and feed evaluation.
An investigation to the dynamics of feed consumption allows us to get clear understanding of the feeding behaviour by sheep. It was found that restriction of daily time of access to feed (480 min/d) did not influence the feeding behaviour characteristics of individually penned sheep. However the physical form and the type of the feed offered affected feeding behaviour, particularly the number of meals, duration of eating and rate of ingestion. Sheep allocated a similar amount of their time to the eating of pelleted feeds, irrespective of the plant origin of the pellets. Also sheep took a similar number of meals when offered lucerne in different physical forms.
To date, most of the methods for investigating ingestive and masticative behaviour involve counting jaw movements. A new non-invasive highly sensitive vibration sensor was developed and evaluated. For our application one sensor was positioned around the jaw to detect biting and chewing activities. Another was positioned around the larynx, and detected swallowing during eating, drinking and ruminating.
It was found from scrutinising the dynamics of buccal activity during eating that the behaviour of ingestion of food by sheep was a series of repeated activities. The basic repeated activity has been given the name of an "ingestion event". Each ingestion event consists of three distinct phases, prehension, mastication and swallowing. Each of these phases has distinct physiological characteristics and durations.
The ingestion event concept was used to determine if the ingestive behaviour of sheep was influenced by lucerne feed offered in different physical forms. From this study modifying the physical form of lucerne offered over a time-limited feeding period to sheep had a significant impact on ingestive behaviour. The dominant effect of the physical form was on the rate of ingestion, and time and number of prehension bites (nibbles), including the number of manipulative chews and time spent on manipulation chewing, and the time spent on mastication activity. Rate of ingestion was higher when the form of the feed was changed from crumble to pellet. Sheep ate stems in the lowest rate, which increased twofold their rate when given leaves only. Sheep had the highest rate of swallowing when they ate pellet feed. Total jaw movement per ingestion event was the highest when the sheep were offered crumble feed and lowest when offered leaves.
It can be concluded from research presented in this thesis that (1) the mechanism of ingestion of feed by sheep or ruminants could be understand clearly through the intensive observation of ingestive and feeding behaviour, (2) sheep modify their ingestive and feeding behaviour to cope with feed types and (3) better understanding of these aspects may allow better management practice and in turn increased the animal production.