Winter grazing is a balancing act
Published 09/09/2015 | 02:30
We are currently milking 240 cross-bred cows on a free draining 80ha milking platform which consists of both owned and leased land. Our target is to milk 280 cows in 2016 giving a stocking rate of 3.5 cows/ha. The herd is yielding 18 litres at 4.7pc fat and 3.95pc protein - 1.6kg of milk solids on 0.8kg of a 14pc nut.
Along with Noel O'Toole we hosted the Irish Grassland Association summer tour last July. One of the areas that generated a lot of interest was our achievement of a 290 day grazing season on the milking platform and the implementation of a winter grazing programme on the outfarms. Our overall stocking rate is 2.2LU/ha on a dry farm with average rainfall of 1,250mm (50in) per annum.
Our target is to reduce costs during the winter period by including as much grazed grass in the diet as possible. This involves bringing the animals to the grass rather than the norm of bringing the grass/silage to the housed cows. To achieve this the lime, phosphorus (P) and potassium (K) status of the soil needs to be index 3 and nitrogen must be applied in August to boost grass growth.
Over the years this practice has allowed us to increase cow numbers and continue to expand the herd and generate milk sales before we put the winter housing in place.
It has also resulted in grazed grass replacing more expensive feeds such as silage and concentrates.
In this article I am going to focus on the role of the outfarms whose function is to rear the young stock and provide all the winter feed for the herd during the dry period in the form of silage or winter grazing.
While there is adequate slurry storage in the lagoon, we do not have enough housing, therefore some cows and heifers are out-wintered. This process starts on August 15 every year when we bale any surplus grass to ensure a clean base.
We then apply 1.5 bags per acre of 18-6-12 along with one bag of 50pc K. Demand is currently 18kg of drymatter (DM) per hectare on the outside blocks and this allows us to build covers for winter grazing.
The nitrogen is limited to 27 units/ac because some of the grass will be growing for 80 days when grazed in November and December.
An average growth rate of 30kgDM/ha will deliver 2,500kgDM/ha of upright pasture that will be easier to manage throughout the winter period.
On the main heifer rearing block the weanlings and the in-calf heifers commence a normal Autumn rotation plan on October 10.
This allows us to maximise winter grazing while also ensuring that there will be adequate grass available when the yearlings are turned out in February.
This block is finished grazing by November 20 when the weanlings are housed on silage and 1-2kg of meal - we have adequate housing for them.
The in-calf heifers are then transported 5km to John Moran's farm where covers of 2,500kgDM/ha will be available. John allocates the grass in 24 to 48 hour blocks as the weather dictates. There is no meal fed to the heifers and over the last few years we have been able to keep them on grass until December 31.
We calve all heifers at two years and we ensure they get a long dry period at the end of the first lactation. We always scan the herd around September 20 and all February to March 1 calvers are earmarked for drying off in mid October.
They are dosed for fluke and worms then transported off the milking platform (MP) on to one of the out blocks until early December. This grass has not been growing as long and is superb quality at 1,500kg to 2,000kg/DM/ha.
It has been our experience that these first calvers transform into mature cows during this period of rest.
The other group of cows we move on to the outfarm in early December when we dry off are the late March to April calvers. This group is kept out on a combination of grazed grass and round bale silage until February 15. Then they return home where the stocking rate on the out-wintering pad is falling as calving progresses.
A tactic we use to minimise damage throughout this period is to feed silage on the dry days and allocate more grass in wet conditions.
There is nothing fancy required in their diet as this group are dry for four months and will be on the normal dry cow regime including minerals for 40 days before calving.
Henry and Patricia Walsh farm in Oranmore Co Galway along with their son Enda and neighbour and outfarm owner John Moran