While the majority of cattle on Irish farms are housed from autumn until spring, there will be a number of farms operating on drier land that winter cows on forage brassicas.
Grazing crops such as kale or forage rape can work out cheaper than conventional housing and silage systems.
There is also the added benefit of having less slurry accumulating in storage tanks, as well as having cows in a fitter condition prior to the onset of spring calving.
But there are a few things to keep in mind from a management point of view, some of which are outlined as follows.
Fluke and worms
While outwintered cattle tend to be healthier than those in highly stocked sheds, these animals will still be exposed to parasites such as liver fluke.
Therefore, keep a close eye on cattle condition for signs of a fluke burden. Taking a few faecal samples mid-winter will indicate if a follow-up drench is required in January.
The same applies to worms when young stores are wintered outside and have access to a grass lie-back area.
Forage brassicas are low in minerals, particularly iodine, which can have negative effects on calving. Therefore, cows will need supplementing with minerals.
Using powdered minerals works well and adding 1kg/head of rolled barley helps to bulk out minerals when fed in troughs.
Feeding minerals daily is a good way to check on stock for signs of any health problems.
A mineral bolus also works well. With a bolus, there is some comfort in knowing all stock are covered.
Lick buckets do work, but are less reliable, as not all cows will use them.
Be wary of frost
Temperatures are getting colder and ground frost is becoming more common.
Where cattle are grazing forage brassicas, frost poses a health risk, as it increases nitrate levels in the plant, which can potentially poison animals.
Therefore, on frosty mornings, do not move the fence as normal. Wait until the frost has thawed before moving the wire.
Offer cattle an extra bale of silage until the wire fence can be moved, helping to keep animals settled.
Forage brassicas are also low in fibre, so make sure cattle always have access to silage, haylage or straw.
To avoid rumen problems, forage crops should be limited to around 50% of dry matter intake, with the remaining 50% coming from the silage or straw bales provided.
As a rule of thumb, one round bale of silage should feed 30 cows every day. If bales are being eaten at a faster rate, then increase forage allowance.
Ideally, bales will have been placed in the field in early autumn so that machinery is not required to enter the field in mid-winter. This stops soils being damaged.
When to stop grazing
With forage crops such as kale, when the plant starts to flower in early spring, stop grazing and remove cattle from the field.
Flowering plants are toxic and cattle are more prone to problems such as redwater, goitres and a sudden loss of appetite.
Therefore, be vigilant as winter transitions into early spring.