Higher lamb growth rate and less worms when grazing multi-species swards
A study carried at UCD (University College Dublin) Lyons Farm during 2015 and 2016 showed that lambs produced from multi-species swards were heavier at weaning and reached slaughter weight quicker than those on grass only swards.
- Perennial rye grass (PRG) only;
- PRG and white clover (PRGWC);
- A six-species sward (6S) consisting of PRG, timothy, white and red clover and two herbs (ribwort and plantain);
- A nine-species (9S) sward containing cocksfoot, birdsfoot trefoil and yarrow in addition to the six species listed in the third sward above.
The experiment started at turnout (post lambing) and continued until all lambs reached slaughter weight and the ewes were housed in early December 2015 and late November 2016.
At 14 weeks post lambing, all lambs were weaned and thereafter a leader–follower system was operated, whereby lambs grazed ahead of the ewes within their allocated sward type.
Average daily gain
Lamb live weight was recorded fortnightly to calculate average daily gain (ADG) and lambs were drafted for slaughter at 45kg.
On average, lambs produced from these swards took 24 weeks to reach the targeted slaughter weight from birth.
In contrast, lambs produced from the grass-only sward (PRG) had the lowest ADG from birth to weaning compared to all other sward types.
In addition, these lambs also took an extra two weeks to reach the target slaughter weight of 45kg compared to those on multi-species swards.
A faecal egg count (FEC) was recorded fortnightly from each individual lamb in each of the four farmlets. When a FEC above 400 eggs/g was detected, then the infected animals in the corresponding farmlets were treated with an appropriate wormer.
Lambs from multi-species swards required fewer treatments for worms than lambs from grass only (PRG) and grass-clover (PRGWC) swards.