The performance and intake of weaned lambs grazing S24 perennial ryegrass, with and without supplementation

Abstract

Two forms of supplement, barley or dried grass pellets (G) were given to weaned lambs, set-stocked at pasture, at three stocking rates (43-5, 60 and 87 per hectare). The supplements were given either from weaning or from the time growth rate fell below a target value. The supplements significantly increased the proportion of lambs reaching the target weight (35 kg) and G was significantly better than barley, but slightly more G was given. The substitution value of supplement for herbage was 0-48 + 0-12 and there was no difference in this value between barley and G. The proportion of lambs reaching the target slaughter weight was not influenced by whether the supplement was offered at weaning or delayed until lamb growth declined below a target level. Increase in stocking rate depressed the herbage intake and growth rate of the unsupplemented control lambs.

The effect of herbage allowance on herbage intake and performance of lambs grazing perennial ryegrass and red clover swards

“…The maximum intakes of S. 23 perennial ryegrass obtained in Expt 2 are similar to those of the unsupplemented lambs grazing S. 24 perennial ryegrass at a high stocking rate of 87 lambs/ha reported by Newton & Young (1974) and to those reported by Langlands (1972) for 110-to 149-dayold weaned lambs grazing a Phalaria ticberosa -Trifoliurn repens pasture "with ample herbage available. However, these are only 50% of the intakes reported by Langlands (1973) for lambs of the same age on similar pasture.…”

Supplementary forage for grazing sheep. 2. Effects on weaned lambs

“…In the case of the silage, supplement DM intakes were similar to cereal DM intakes in supplementation experiments where improvements in growth rate were obtained (Newton and Young, 1974) and represented about 40*^^0 of the DM intake requirement (MAFF, 1975). However, growth rate of the lambs was not increased although stocking rate was increased by 25%, suggesting a high substitution rate.…”

“…Finishing lambs on pasture usually show a good response to supplementary concentrates (Newton and Young, 1974), with substitution rates of approximately 5O-6O"7o (Holder, 1962;Langlands, 1969;Newton and Young, 1974). However, early experience of the supplement is important, particularly in the presence of the dam, to stimulate allelomimetic feeding behaviour and allow the rumen microbial population to adapt.…”

“…However, early experience of the supplement is important, particularly in the presence of the dam, to stimulate allelomimetic feeding behaviour and allow the rumen microbial population to adapt. In the latter respect dried grass has been found to stimulate Iamb growth more than barley (Newton and Young, 1974), probably because the existing rumen microbes in pasture-fed lambs are more suited to the digestion of dried grass. Hence, it was considered that a forage supplement could stimulate growth more effectively and at a lower cost than cereal-based concentrates.…”

Effects of concentrate supplementation and herbage allowance on the performance of grazing suckling lambs

“…There is general agreement in the literature that animal response to supplementation is likely to vary with herbage availability. When herbage is restricted, concentrate supplementation may increase total digestible organic matter intake and performance, because there is little or no substitution of herbage by concentrate; in contrast, when herbage supply is ample, supplementation may result in a low response in intake and performance, owing to substitution of herbage by concentrate (Newton and Young 1974;Young ero/.. 1980;Milne e/a/., 1981;Jennings and Holmes, 1984;Meijs and Hoekstra, 1984;Kibon and Holmes, 1987). However, few scientists have really tested or shown a significant interaction between these two factors on herbage intake (Meijs and Hoekstra, 1984); none have shown it on animal performance.…”