The lowland flocks participating in the Teagasc BETTER farm sheep programme have collected their seven-week lamb weights in recent weeks and a summary of the weights is presented in Table 1.
Target average daily gain (ADG) for the flocks is for twin-born lambs to be achieving an ADG of
greater than 280g/day from birth to seven weeks for lambs being reared on ewes receiving no concentrate supplementation post-lambing.
As can be seen from the table, performance to seven weeks of age in most of the flocks is on target and, in many cases, has exceeded the targets set.
The seven-week weight is an important measure of flock performance, as not only does it give an indication of how the lambs are performing, it also gives an indication of ewe performance.
Up to six to eight weeks of age, lambs are getting most of their nutrient requirements from their ewes’ milk and poor performance to this point can indicate ewes are not producing enough milk to meet lamb requirements.
As a result, where possible, these weights will be used not only to identify underperforming ewes, but also when selecting replacement ewe lambs later in the year to try to identify ewe lambs from ewes that had the best litter growth rates to seven weeks post-lambing.
Grassland management has been a key element to the good performance figures recorded at seven weeks and will become even more important up to weaning, as the lambs begin to rely more on grazed grass to meet their nutritional requirements.
As such, ensuring that the flock has good-quality grass in front of it is vital to keeping performance levels on target up to weaning time. Weaning in the flocks will take place at approximately 100 days (14 weeks) from the mean lambing date.
Grassland management and lamb performance from seven weeks to weaning has a major bearing on farms achieving the target performance from birth to weaning of in excess of 260g/day.
If lambs do not have quality grass in front of them, then average performance can quickly fall below this figure.
Grass growth increasing
Grass growth for the Teagasc BETTER sheep farms has been variable during the month of May, with grass growth rates behind where they would normally be expected to be.
As a result, some of the flocks had to re-graze ground closed for silage in order to meet grass demand for the flock.
Growth rates in the last week are rising back to more typical levels, meaning a careful eye will have to be kept on grass quality ahead of the flocks.
The flocks will be targeting 10 grazing days ahead from early June and the days ahead has risen quickly recently, requiring the flocks to take action to maintain control.
This will mean dropping out paddocks with heavy covers for saving as silage and sub-dividing paddocks as necessary to keep to this days ahead target.
These management practices are essential in maintaining good-quality grass in front of the flock and ultimately help to optimise performance.
Post-grazing heights will also be increased to approximately 5cm, so that lambs are not being forced to clean out swards.
It will be important that these swards are grazed out fully, either by dry hoggets following behind the ewes and lambs or else by the ewes after weaning during the next rotation.
While management tasks can vary greatly from seven-week weighing to weaning, all of the flocks will also have it in the back of their mind to manage the grazing rotation so that there is a supply of top-quality grass available post-weaning.
Faecal egg count analysis will also be used from now on to establish the need for worm control.
A big focus in recent years has been to establish if anthelmintic resistance is an issue on farms through the use of faecal egg count reduction tests and this will remain a focus where there is any doubt over the efficacy of an anthelmintic class or fears that resistance could be developing.