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Observations on the nature of two roughage diets collected from nine oesophageal fistulated, pen-fed sheep on twenty-three occasions are reported. The diets were lucerne chaff and a wheaten grain-chaff mixture. The fistulas were of three types. Six were latex plug stoppered fistulas with relaxed orifice diameter of 1.5 to 3.0 cm ; two were fitted with rigid screw-capped acrylic cannulas of diameter 2.5 cm ; and one was an early Torell type fistula with a 6.0 cm by 1.0 cm orifice. Over 35 per cent of the diet can be recovered from these fistulas, which is satisfactory. Mean recoveries (pooled with respect to diet) were 36 per cent for acrylic cannuluted fistulas, 46 per cent for latex plug stoppered fistulas, and 82 per cent for the Torell type fistula. For all fistulas recovery values varied widely. On the lucerne chaff diet the nitrogen content of the extruded material did not differ significantly from the feed eaten. However, the ash content was significantly increased (P<0.05). On the diet of wheaten chaff and wheaten grain there was a slight, but not significant tenden9 for the extruded material to contain a higher ratio of chaff to grain. In vitro treatment of succulent grass and dry oaten straw with saliva confirmed that the increase in ash content was of salivary origin. There was no evidence that saliva either leached nitrogen from or added it to these feedstuffs |
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