By Charlotte Westwood, Veterinary Nutritionist
The importance of transitioning
All of us are passionate enthusiasts about keeping our stock happy, healthy and well through the winter. That said, at any stage through the winter, occasional challenges come along that threaten to trip us up such as winter storms, bogged tractors, power loss to fences and break outs over the wire by those belligerent individual animals who really do think that the grass (or crop) is greener on the other side of the fence.
Realistically though, almost all our animal health challenges occur during the first 2-3 weeks of winter crop feeding, during the “transition period”. This is that time that we step our sheep, cattle and deer off a largely pasture-based diet onto a diet of a range of winter crops – including winter brassicas (forage rape, swedes, kale or winter turnips), fodder beet or greenfeed cereals such as oats. Depending on crop type, transitioning can be very challenging (e.g. pasture to fodder beet) or relatively straight forward (e.g. pasture to greenfeed cereal). Therefore, there is not ‘one size fits all recipe’ for all crop types, and transitioning is typically a little more straightforward for sheep and deer than it is for cattle. Furthermore, sometimes dairy cattle can be a little trickier than beef cattle, due to dairy cows tending to be more voracious eaters than beef.
Despite some differences between crop type and stock classes, the same broad principles apply when running a check list to make sure your transition feeding planning is all in place.
- Update feed budgets
Feed budgets require one last revision before stock go onto crop. Even if you had some dry matter (DM) yields completed back in late April or early May, it still pays to do a final DM yield on crops before stock go on, specifically around getting crop allocation during transitioning just right.
In instances where crops were planted later, bulb crops may be a bit light on bulb size, and heavy on top yields. It may be that a few extra few weeks of growth has allowed your swede, turnip and fodder beet bulbs to bulk up a bit more through June. This in turn will have potentially changed slightly your transition planning and therefore your planned allocation (m2/head) or row calculations for precision planted swedes or fodder beet.
- Do remember to send samples away for DM% testing on winter crop
Even though you might have done an early crop yield during May, the DM% can change through May as the crops continue to grow. For example, bulbs of fodder beet and swedes that were quite small a month ago but have ‘bulbed up’ more during May might have changed DM%. Typically, smaller bulbs have higher DM% and big bulbs lower DM%, so it isn’t ideal to assume things haven’t changed.
It is also really important to include a nitrate test with your crop samples sent away for DM% analysis.
Revising your feed budget in late May helps balance feed demand by stock and feed supply from crops, supplements and runoff pasture. Demand may still be higher than planned if you’re more highly stocked due to the works capacity issues through April/May.
- Recheck inventories of supplement
Recheck inventories of silage, baleage, straw and hay, and allow for additional supplementary feeds and runoff pasture that during winter storms. Hay, straw and high DM% baleage create a “hot” rumen fermentation, keeping stock warm in cold windchill events. Runoff paddocks must provide shelter from prevailing winds in storm events.
Check hay and straw for water damage or mould, and baleage for damage to outer wrap layers, excessive spoilage and presence of ergot in seed heads. Collect samples from supplementary feeds for feed testing, including DM %. Knowing a feeds DM % helps more accurate calculation of tonnage of silage/baleage DM on hand and helps with feed out decisions.
- Extra supplementary feeds during transitioning
Feed budgets must include sufficient supplementary feed to offer stock during the transition from pasture to winter crop. “Transitioning” involves the step-wise, gradual lift in amount of crop on offer over a minimum of 10 days (brassicas) and 21 days (fodder beet). Transitioning typically starts off with crop being offered at less than 10% of the animals daily feed requirement and, over a period of up to 3 weeks (depending on crop type) gradually stepping through to crop delivering no more than e.g. 75% of the diet for winter brassicas and, based on recent DairyNZ work, no more than 60% for fodder beet.
You need to plan to feed relatively more supplementary feed during transition, and the amount of supplementary feeds you’ll need during transitioning varies depending on crop types. Quality of winter greenfeed cereals is “somewhat” similar to pasture (cereals might be lower NDF than autumn pasture) so typically your transition period of perhaps 5-7 days will be less critical to get right than for the other extreme of crop types – fodder beet – requiring around 21 days to transition. Time to transition onto brassica crops is somewhere in between, allowing perhaps 10-14 days to transition onto crop.
For feed budget purposes a rule of thumb for the transition period can be; “budget for enough supplements (runoff pasture, silage, baleage etc) to feed at an average of 50% of the total diet (with 50% balance as crop) for the duration of transition”. So for dairy cows going onto kale, if you’re planning e.g. a total of 14 kgDM/head/day offered through transition for a 10 day transition period:
14kgDM/cow/day x 0.5 (50% of diet as supplements averaged over the transition period) x 10 days transition = 7 kgDM supplements/cow x 10 days = 70 kgDM/cow of supplements needed over the transition period and 70 kgDM/cow as kale.
Fodder beet example:
If the same cow example (above) is used, the same calculation applies, except we should allow a total of 21 days transition. Again, if we allow an average of 50% of the diet as supplement during the transition period to be supplements:
14 kgDM/cow/day x 0.5 (50% of diet as supplements averaged over the transition period) x 21 days transition = 7 kgDM supplements/cow x 21 days = 147 kgDM/cow of supplements needed over the transition period and the balance of 147 kgDM/cow as fodder beet over that 21 day period. This is a lot of extra supplements to add into your budget, rather than just doing your numbers based on e.g. 4 kgDM of supplements/head/day average for the whole of winter!
- The people factor during transitioning
And last but by no means least, our people and their well-being is so important through winter – but especially when stock are transitioning onto crop. Spending extra time on getting transition feeding right is time well spent if there’s no unwell stock to attend to – so stressful not only on our stock but stressful for us too.
If winter grazing is a long drive from home, days can be long too – pack heaps of food and snacks, spare clothes and keep warm and well. Staff might be new to the business and still figuring out how things work. Be patient while new relationships and routines sort themselves out.
Make sure those rosters are as best as they can be – so everyone can have some time off to catch up on family time and some sleep.