Relationship between rate of intake and daily intake of dry, mature subterranean clovers by sheep

Abstract

Proc. Aust. Soc. Anim. Prod. 1996 Vol. 21 RELATIONSHIP BETWEEN RATE OF INTAKE AND DAILY INTAKE OF DRY, MATURE SUBTERRANEAN CLOVERS BY SHEEP XR. WANGA, S.K BAKERBC and D.B. PURSER B *Faculty of Agriculture, The University of Western Australia, W.A. 6907 B CSIRO Division of Animal Production, Private Bag, PO Wembley, W.A. 6014 'Centre for Legumes in Mediterranean Agriculture, The University of Western Australia, W.A. 6907 In penned sheep fed dried grasses, rate of intake in a 30-minute test was positively correlated with daily intake (Forbes et al. 1972). In sheep fed dry, mature subterranean clover (Trifolium subterraneum), analyses of the data by multiple regression showed that rate of intake was inversely related to the number of chews/g DM during eating. In turn this was related to the proportion of leaf and to the energy required to compress the clover (Wang et al. 1995), and since daily intake appears to be related to the proportion of leaf in the clover on offer (Taylor et al. 1989), these results suggest that the rate of intake and daily intake of clovers may be correlated. Four cultivars of mature, dry subterranean clover, Trikkala, Dinninup, Daliak and Dalkeith, were harvested from field plots, separated into leaf-enriched (` leaf) and stem-enriched (` stem' fractions by sieving ) and used to determine rate of intake (Wang et al. 1995). Briefly, rate of intake was tested with 6 mature, merino wethers using a 12 x 12 Latin square design, in which each sheep was offered twice each of the 3 fractions (` leaf, ` stem' and unfractionated) of each of the 4 cultivars. Each fraction (150g) was offered to the sheep for 3 minutes and the residue was weighed to calculate the rate of intake. Daily intake was determined over 14 days after a 7-day acclimatisation period using 48 mature, merino wethers. The same 4 cultivars harvested from the same field plots were used in this experiment (4 cultivars/3 factions x 4 sheep), and they were offered at 10% in excess of the previous day' intake. s The rate of intake (g organic matter (OM)/min) of ` leaf of each cultivar was significantly higher than that leaf stem' and of ` stem'(PcO.01). The rate of intake of unfractionated clovers was intermediate between ` and ` it differed among cultivars (P<O.Ol). Trikkala was eaten faster than any other cultivars. Dalkeith was eaten more slowly than Daliak and Dinninup. There was no difference between Daliak and Dinninup. Daily intake (g OM/day) followed a similar pattern to rate of intake. Since the hypothesis was supported that daily intake and rate of intake are correlated (r=0.72) (Figure), then the resistance of forage to compression may be a factor involved in controlling daily intake. FORBES, J.M., WRIGHT, J.A. and BANNISTER, A. (1972). Anim. Prod. 15: 211-4. TAYLOR, G.B., ROSSITER, R-C., PURSER, D.B. and COLLINS, W.J. (1989). Proc. XVI Intemat. Grass. Congr., Nice France, pp. 809-10. WANG, XR., BAKER, SK. and PURSER, D.B. (1995). Ann. Zootech. 44 Suppl. 256. 467