The effect of feed quality and particle length on the short-term intake rate of Friesian heifers
Abstract
Short-term intake rate measurements were performed on four 20 month old Friesian
heifers with mean live weight of 344 kg. Treatments were forages of two qualities;
ryegrass straw (low), and oaten hay (high), and four particle lengths (5, 10,20 and 40
cm). The intake rates of each forage type offered singly (S-straw and S-oat) and in all
possible paired combinations of particle lengths (40-20,40-10,40-5,20-10,20-5,10-5)
for both forage types (P-straw, P-oat) were measured over 3-5 minute periods.
Feed quality had a highly significant effect (P<0.01) on intake rate. Mean intake rates
were 36 and 69 g/min for S-straw and S-oat respectively. There was no significant
difference in intake rate between the particle sizes in either the S-straw or S-oat
experiments. When the between-animal variation was removed the particle length of
oaten hay had a significant effect on intake rate. The change in intake rate between 5
and 20, and 20 and 40 cm was significant for both S-straw and S-oat. The particle
lengths giving the faster intake rates in the single offerings experiments were
generally consumed in higher proportions in the paired feeding trials. Intake rates in
the P-straw and P-oat experiments reflected the intake rates associated with the two
feeds induded in the combination, as indicated by the S-straw and S-oat experiments.... [Show full abstract]