Paddocks allow us to fine-tune grass use
Published 18/05/2016 | 02:30
A key message coming from the recent Irish Grassland Association sheep conference held in Aughrim was the benefits of paddocks to increase grass output and utilisation. This was evidenced during the visit to John Pringle's farm who was applying this system.The use of paddocks allows better grass recovery, and more grazings overall on the farm each year. This also allows us to deal more comfortably with periods of grass shortage, as have been experienced in many parts of the country recently.
Understanding ewe demand and grass supply are key aspects of managing grass successfully. We are allocating 3kgDM of grass per ewe per day at the moment with lambs offered 0.7-0.9kgDM per head per day during May. As the year progresses the ewes' demand and allocation will decline and the lambs' demand and allocation will increase. This information on what the ewes require is of limited benefit if we do not know the amount of grass grown or have a mechanism (ie paddocks) to offer this to the sheep.
To this end, Connie Grace does a farm walk every week to assess the amount of grass available.
As Connie is basically running four separate farms as part of her studies this is not an insignificant task, but it does give us great confidence in the grazing decisions we make. If grass supply is running short we can slow down the rotation. We have not had to do so, despite being quite heavily stocked at 12.5 twin-rearing ewes per hectare. But we do not have any of this grazing platform closed for silage either.
The warm weather coupled with rainfall is driving on grass growth at Lyons. The soil temperature on the research platform is comfortably above 10C and grass growth is responding on the SMARTGRASS platform, but given the elevation, topography and aspect of this site, coupled with somewhat lower nitrogen inputs, growth rate is always going to be lower here in comparison to the dairy platform on the farm.
Following a challenging start to their life when growth rate was just over 300g per day during the first month of life, the lambs have recovered well and are now growing at slightly under 350g per day. This is still back on last year. Following the nematodirus hatch forecast from the Department of Agriculture, lambs were dosed last week. They were foot-bathed at the same time - as the lush grass presents ideal conditions for scald. While our experimental lambs are weighed every two weeks, the remaining lambs will be weighed this week as part of the Sheep Ireland Central Progeny Test program. This gives us very good data on the best milk producing ewes in the flock, but perhaps more importantly it also highlights the poor performers that will be ear-marked for culling.
As part of our experimental work we record ewe weight and body condition score every two weeks in early lactation. This data is telling us that ewes are mobilising a lot of body reserves in the first three weeks of lactation, with up to 9pc of body weight being lost during this window. This shows that intake is not able to meet demand and body reserves are making up the difference. Ewes can recover from this quickly and we are seeing that half of this weight is recovered between weeks three and six, assuming the feed is there for the ewes.
Most importantly the ewes' energy-demand peaks around three to four weeks into lactation but her intake does not peak until week five to six of lactation so this needs to be manged very carefully.