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A total of 960 sheep were used in a factorial experiment to test the effects of four treatments aimed at improving responses to molasses-urea blocks. The treatments were (a) 200 g oat grain sprinkled on the top of the blocks once daily for the first 7 days, compared with the absence of oats; (b) the inclusion, for the first 2 days, of four additional sheep that had previous experience with blocks and were regular consumers of them, compared with the absence of such sheep; (c) the use of quiet, handled ('tame') sheep, compared with sheep that were relatively nervous and frightened ('wild') ; (d) the use of three differently-constituted blocks, containing 0, 5 and 10% urea, compared with three blocks of the same formulation, containing 5% urea. Each group comprised 20 sheep confined in yards and fed hay in addition to the molasses-urea blocks. The intakes of blocks, and the number of sheep licking the blocks during 3-week periods were measured. In general, the treatments had no consistent effects on the responses of the sheep, but some groups of sheep were more responsive to particular treatments than others. There were no obvious reasons for such variability, Intakes of blocks increased with time (3660, 6373 and 81 25 g group week-1 for weeks 1, 2 and 3, respectively), and the percentage of groups that had consumed a block by the end of each week increased with time (86, 89 and 96% in weeks 1, 2 and 3 respectively). It was concluded that it is extremely difficult to influence the behaviour of sheep by management procedures such as those used in this experiment.

Two experiments are described. In experiment 1, penned sheep were fed oat grain, hay and molasses-urea block prepared with added chromic oxide (Cr2O3). Recoveries of the marker calculated from measured intakes and faecal outputs were: oats 98.0 � 5.1%, hay 97.5 � 3.2%, molasses-urea block 89.2 � 11.5%. The lower and more variable recoveries of marker from the block were attributed to uneven mixing of the marker. In experiment 2, three groups of 15 mature Corriedale wethers were allowed to graze freely, and supplements of oats, hay or molasses-urea blocks, prepared with added chromic oxide, were offered to each group in rotation during three 4-week periods. During the first two weeks of each period the group offered molasses-urea block was confined in a small yard with a block, and fed hay, to accustom the sheep to the block and to ensure that all sheep in the group were licking it. Total faecal collections were made during 14 days from the time of commencement of feeding of the prepared supplements, and the intakes of the supplements were calculated from the total amounts of marker excreted. The mean intakes over three periods (uncorrected for Cr2O3 recoveries) were : oats 1851 � 434, hay 3326 � 1014, molasses-urea block 11 7 � 1 6 8 g/head week-1. Intakes by individuals ranged from 1086 to 2679 g week-1 for oats, from 1508 to 6048 g week-1 for hay, and from 0 to 732 g week-1 for molasses-urea block. Of the 45 sheep used, 8 sheep did not consume any of the block within the measurement period, despite having consumed some block in the preceding 2-week period

A total of 11 88 sheep in seven flocks on five farms were offered molasses-urea blocks under grazing conditions. After 3 weeks, 50% of the sheep had licked the blocks but there was wide variability between flocks in the proportion of sheep that licked and their average intakes. Sheep that did not lick the blocks while grazing were confined in yards and offered the blocks plus 350 g hay/sheep day-1. After 3 weeks, 81% of the sheep had licked the blocks. A second confinement period of from 2 to 4 weeks was imposed upon those sheep that had still not licked, and this resulted in 88% of them licking. The remaining seven sheep consumed the block only after being penned individually. It is concluded that special management procedures may be required to encourage grazing sheep to lick molasses-urea blocks.

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