Time, attention to detail and patience are required to minimise the risk of animal health issues when transitioning stock onto winter forage crops.
Dr Will Halliday, Beef + Lamb New Zealand’s Senior Manager for Technical Policy, says successful transitioning onto winter forage crops begins with small amounts of crop, while the bulk of the diet is made up of pasture and /or supplement such as silage, baleage, hay or straw.
“While it is a time-consuming process, it is important to help prevent ruminal acidosis and ensure stock make the most of the high-quality feed on offer. I encourage farmers to have a Winter Grazing Plan in place which details how the transition phase will be managed and describes good grazing practices once stock are successfully transitioned onto winter forage crops.”
Additional bale feeders can be useful during the transition phase so stock, particularly cattle, can easily access supplementary feed. Better quality feed can also be offered during this time so animals will want to eat more supplement and less crop.
Each day, slightly more crop and slightly less supplement is offered. This transition should take 10-14 days for brassicas (starting with an hour a day) and up to three weeks with fodder beet (starting with 20 minutes per day).
Prior to feeding crops, Dr Halliday recommends farmers get an accurate drymatter yield of the crop and take drymatter percentage measurements on samples from each paddock.
These measurements, combined with crop area, will allow farmers to more accurately calculate their daily allocations.
B+LNZ’s FeedSmart tool is particularly useful for calculating crop allocations and can be used in the paddock.
Dr Halliday says it is important to keep a close eye on animals, especially during the transition phase. Individuals will behave and consume differently which can put them at risk of ruminal acidosis.
For example, dominant feeders may compete well at the crop face and not bother to eat any supplement. This puts them at risk of ruminal acidosis. Others may prefer baleage and eat less crop or are less able to compete on the crop. This puts them at risk of underperforming, particularly if the supplement offered is of average or poor quality.
The clinical signs of mild to moderate ruminal acidosis include diarrhoea (it may be watery), reduced appetite and depression while animals with moderate to severe ruminal acidosis may be staggering, have difficulty rising, bloating, profuse smelly diarrhoea and in severe cases, be recumbent, in a coma or dead.
Breakouts are always a risk with cattle on forage crops. High voltage electric fences and double fences can help prevent this, particularly in the transition phase.
With cattle, Dr Halliday suggests farmers aim for long crop faces, so cattle can stand shoulder to shoulder and all cattle can access the crop at the same time.
Stock should always have access to clean water. Ideally, water troughs should be placed well away from bale feeders. This means dominant cattle must move away from the bale feeder to get water, allowing other cattle access to supplementary feed.
More information
- Resource book: Forage cropping management (PDF, 2.3MB)
- Knowledge Hub resources: Winter grazing