Tommy Boland: Creep grazing offers multiple benefits for lambs
The main crop of lambs at Lyons are 11 weeks old this week. This is an important juncture, because at this stage the lamb is starting to become more dependent on grass intake to support its energy needs and daily live weight gain.
Up to about six weeks of age the lamb is largely dependent on the ewe's milk supply.
Between week six and week 10, the daily demand for grass dry matter intake by the lamb increases from 0.3kg DM to 0.7kg DM per day, with ewe demand for grass dropping by a similar quantity.
This move to a more grass-based diet presents a number of challenges for the lamb and the farmer.
Firstly, grass is less energy-dense than milk, so we must ensure that the grass available to our lambs is of the highest possible quality.
This year there is an adequate supply of grass on many farms. So rather than grass being in deficit, achieving the correct post-grazing sward height - which will influence grass quality in second and subsequent rotations - is proving to be more of an issue than in many years.
As the lamb becomes more grass-dependent, it is crucial to maintain grass quality.
At high stocking rates, high litter size or where it is a struggle to hit target residuals, creep grazing may offer benefits for lamb performance.
There is evidence to show it may also reduce the weaning stresses as lambs are more accustomed to being separated from the ewes. However, it does require suitable infrastructure to carry out
Secondly, when the lambs are grazing they are exposed to a wider range of intestinal parasites, with Nematodirus battus causing particular issue for young lambs.
One of the most challenging aspects of dealing with this parasite is that the faecal egg count (FEC) test does not provide us with much information as to when we should treat.
The reason is the immature parasite causes significant damage to the animal before they begin to produce the eggs which are measured in the FEC test.
This means by the time we see the eggs in the faeces, much of the damage is done.
To counteract this, dosing is performed either on a timed basis (ie five to six weeks of age) or in response to the DAFM parasite forecast.
White drenches should still form a crucial part of nematodirus control. While the white drenches have a lot of resistant issues for other classes of intestinal parasites, they are still largely effective in the treatment of nematodirus.
Grass growth at Lyons for May has been in the mid-80s range and the first cut of silage has been harvested.
Over the past number of years considerable focus was placed on improving the quality of silage, with the inclusion of red clover in the silage swards playing a major role.
This, along with other management practices, frequently produces silage with a DMD percentage in the region of 80pc and crude protein contents of 14-15pc.
The benefits of this improved quality are manifest in reduced concentrate feed requirements for all livestock classes, not least the ewes during late pregnancy.
Currently at Lyons, we are establishing swards for our upcoming grazing studies, which will further examine the role of multi-species swards in the diet.
Tommy Boland is an associate professor in sheep production at Lyons Farm, UCD. Twitter: @Pallastb Email: email@example.com
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