This study was carried out to investigate the use of high-level feeders (HLF) in both indoor and out-door experiments to study the foraging behaviour of sheep. The work was based on a series of experiments: (1) Preliminary study to investigate the use of highlevel feeder to examine the foraging behaviour of sheep; (2) The effect of alternative feed sources on the behaviour of Welsh Mountain and Cambridge ewes given access to ivy on a high-level feeder; (3) Interaction between breeds and alternative feed sources on the behaviour of sheep given access to ivy on a high-level feeder in a grazing environment; ( 4) The effect of forage quality on the behaviour of Welsh Mountain ewes
when sources are available separately; (5) The effects of location of forage on the
behaviour of sheep when medium quality forage is available; ( 6) Selection of forages by sheep when sources are available simultaneously; (7) The extent to which sheep will overcome an obstacle in order to eat from a high-level feeder; (8) The effect of priorforaging experience on the foraging behaviour of ewes given access to ivy; and (9) The effect of forage locations on the feeding behaviour of sheep when good quality forage was available. The expriments demonstrated that the high-level feeder technique can be used to simulate foraging from a tree since the behaviour of ewes during eating ivy and sycamore from the HLF was similar to that observed when they ate from a real tree.
Some aspects of ewes behaviour was affected by the availability of other feed sources. The provision of hay and concentrate supplement did not significantly reduce the intake of ivy but ewes tended to spend less time eating ivy from the HLF when hay and concentrate supplement were available. There was no breed effect on the time spent grazing or eating from a HLF. A reduced intake per ewe in a mixed-breed treatment grazing was the result of competition between ewes particularly related to size and the increase in numbers of ewes eating together. Ewes selected ivy > hay > straw. They spent more time eating from the HLF when good quality forage was available (18.8%), less at medium (9.3%) and very little (0.1%) if poor quality forage was available. Welsh Mountain ewes had an ability to select their diet from different types of forage available to them simultaneously. Both the HLF and obstacle techniques are useful techniques
when the degree of preferences for feeds is to be studied. They can also be used to test if an animal species is willing to work to obtain particular foods. It was concluded that sheep have the ability to take a decision to · work · harder in order to move faster to preferred feeds. Preference for location was affected by factors associated with the location (height, safety), the forage available at each location and prior experience.
Prior-foraging experience or training increased the time spent eating ivy from the sources that sheep were accustomed to eating from. Ewes ate ivy from different locations in the order hurdle > HLF > floor. Eating ivy from sources that they did not have experience of indicates that the drive to eat was stronger than their preference for a location. The results of this study also showed that ME obtained from ivy did not meet the maintenance requirement for ewes. In order to meet the daily maintenance requirement ewes would have to eat ivy for longer and considerably increase their intake.