An experiment was conducted to examine the relationships between sward
surface height and the intake and liveweight gain of lactating female
goats and their single kids and of 12-month-old castrated male goats
continuously grazing grass pasture. Herbage intake was measured using
the n-alkane marker technique. Goats grazed the experimental area from
May to August at nominal sward heights of 3-4, 5-6, 7-8 and 9-10 cm.
Sward heights achieved were variable but were consistently ranked in t
reatment order. The herbage intake of females [57-140 g DM (kg LW0.75)
-1 d-1] and castrates [26-88 g DM (kg LW0.75)-1 d-1] increased linearl
y with sward height over the range 3.2-11.0 cm. The liveweight change
of females and castrates reflected the pattern of change in sward heig
ht. The herbage intake of kids [17-41 g DM (kg LW0.75)-1 d-1] was not
related to sward height, but there was a consistent increase in livewe
ight gain with sward height from 98 to 129 g d-1. The herbage intake o
f kids did not increase with age with means of 25-29 g DM (kg LW0.75)-
1 d-1 for kids aged 9-17 weeks. There was evidence that all classes of
goat selected green leafy material of high digestibility.