The hill sheep farmers in the Teagasc BETTER farm sheep programme recently completed the seven week weights on their lambs, as presented in Table 1. The seven week weights are a crucial measurement for the flocks, as they provide a picture of how lambs are performing and an update on how the ewe flock is performing. Lamb performance in early life is largely driven by the milk production of the ewe, so poor performing lambs within the flock can be an indicator of poorly performing ewes.
Overall, the programme farmers were happy with the performance of lambs to-date, with the comparatively benign weather in April and May suiting most hill farms. Single-born lambs, which are usually the biggest mob of ewes in hill flocks, were nearly half a kilogram heavier than this time last year on average for the group.
While lambs being reared as twins were slightly lighter than last year, the mean average daily gain of 220g/day for the group was only slightly behind 2019 levels and is still a respectable performance. With the exception of one flock, all the flocks recorded growth rates over 200g/day for twin-born lambs.
All of the programme farmers are lambing their single-bearing ewes outdoors, with most lambing their twin-bearing ewes outdoors also
For the flock where the performance of the twin-reared lambs was below this, a FECPAK analysis indicated a high worm burden in the lambs, which were on the enclosed ground since lambing. Lambs in this flock have since been dosed.
All of the programme farmers are lambing their single-bearing ewes outdoors, with most lambing their twin-bearing ewes outdoors also. After lambing, the flocks held ewes and lambs on enclosed ground until four to five weeks after lambing, at which point flocks began returning ewes and lambs to the hill. Single-rearing ewes and their lambs were let out first to the hill.
Importance of grazing hills
Twin-rearing ewes and their lambs were put to the hill, or areas of improved hill, following the seven-week weighing in most of the flocks. There is a temptation for the flocks to hold ewes and lambs on their ‘green’ ground for the summer, but it is important that ewes go back to the hill to keep hills in good grazing condition.
Weaning on time is vital to allow ewes recover body condition before mating, but also to put a plan in place for selling the lamb crop
This also provides a chance to build grass on the green ground for weaning and to keep any poorer performing ewes and their lambs on.
Lambs will be weighed again in late July/early August, when they are weaned at approximately 14 weeks of age. Weaning on time is vital to allow ewes recover body condition before mating, but also to put a plan in place for selling the lamb crop.
At weaning time, the proportion of the lamb crop sitting in the weight categories of greater than 35kg, 30kg to 35kg, 25kg to 30kg and less than 25kg, will be assessed. Depending on grass supplies, store lamb prices and facilities on the farm, a plan will be put together for selling these lambs.
Grass supplies putting weaning into sharp focus
Weaning on time is also a crucial management step for the lowland flocks in the Teagasc BETTER farm sheep programme, to allow lambs access to the best quality grass on the farm and reduce the demand for grass from the ewe flock. This year, that is of particular importance, as grass growth rates have declined over recent weeks, leading to some of these farms weaning lambs at 12 weeks of age, as opposed to the usual 14 weeks of age.
Weaning slightly earlier will allow these flocks to reduce grass demand and ensure there is good-quality grass available for the lambs to wean on to. Small numbers of lambs have been drafted by some of the flocks to-date, with all of the programme farmers hoping to get a small draft away at weaning time.
Once weaned, lambs will be put to good-quality swards
Performance of the lambs in the lowland BETTER farm flocks up to seven weeks was very good, with twin-born lambs reared on grass-based systems having a mean average daily gain of 300g/day across the flocks. All lambs will be weighed again in the coming weeks, as they are weaned with flocks targeting a liveweight of 30-32kg in lambs born and reared as twins.
Once weaned, lambs will be put to good-quality swards and allowed graze these to a height of 5.5cm to 6cm before using ewes, once dried off, to clean out the paddocks to a height of 3.5cm to 4cm following the lambs.
Naturally, lamb growth rates drop off from seven weeks of age to weaning as the lamb becomes less efficient in nutrient conversion and more reliant on grazed grass to meet their nutrient demands. This means growth rates at weaning will be behind compared to at seven weeks of age.
A key lesson from the drought in 2018 was the importance of stretching the grazing rotation to allow paddocks a chance to recover
This may be more pronounced where grass supplies have been tight in recent weeks, as farms tried to balance keeping good-quality grass in front of the flock while also dealing with reduced grass growth rates.
A key lesson from the drought in 2018 was the importance of stretching the grazing rotation to allow paddocks a chance to recover. For the BETTER farms affected by the dry weather, this has meant sacrificing fields intended for silage on some of the farms with one farmer introducing silage to dry hoggets and another putting a creep feeder with lambs to reduce grass demand.
All participants have some silage made for next winter, but more is required
Grass growth rates have varied massively throughout this year on the Teagasc lowland BETTER farms, with growth rates recorded last week clearly reflecting this. Growth rates for the farms ranged from 16kg DM/Ha/day in Tipperary and 19kg DM/Ha/day in Wicklow, up to 91kg DM/Ha/day in Leitrim and 107kg DM/Ha/day in Kerry.
The variation shows the importance of grass measuring to correctly identify what is happening on your farm. All participants have some silage made for next winter, but more is required. Grass growth rates will need to bounce back on the drier farms first.