From winter crops to pasture: How can we winter with less mud?

Traditional winter crop systems, such as those dominated by swedes, fodder beet and kale, are characterised as having a high yield from a defined area. They have advantages over pasture species such as continued growth into the winter (to a lower temperature), provide high feed energy with good utilisation, and are simply managed by the farmer.

However, there are disadvantages, namely mud. The mud is problematic due to many factors, such as: 

• Reducing feed intake
• Animals lying on the mud takes extra energy
• Being in the mud can increase disease
• Poor utilisation of feed leading to poor stock performance in bad weather
• Unbalanced nutrition
• Soil pugging can lead to sediment loss
• Nitrate leaching in spring
• Exposure during severe weather events

To mitigate these disadvantages, there are three alternative wintering methods that farmers can employ – multi-graze/multi-species crops, all-grass wintering and bale grazing. 

Multi-graze crops refers to paddocks that are grazed multiple times.  A functional multi-species forage mixture will include a high yielding brassica for bulk (kale, swede, turnips), a regrowing brassica (kale, rape, Raphanobrassica), one or two pasture grasses with cool-season activity for winter and spring growth (Italian ryegrass, Prairie grass), one or two cereals for bulk (ryecorn, oats), some legumes for feed quality and nitrogen fixation (peas, faba beans, clovers) and other species that may be included for environmental reasons such as plantain to help reduce potential nitrate leaching.

In a recent trial, paddocks were grazed first by finishing lambs in late January at 50/ha for 10 days. With a liveweight of 30kg, a growth rate of 300g/day, intake at 2kg/DM/head/day, this totalled 1tDM/ha eaten over the grazing duration. 
The second graze occurred in April by ewes at 50/ha for 42 days. Their liveweight was 68kg, had a growth rate of 100g/day, intake at 1.7kg DM/head/day, this totalled 3.57 tDM/ha eaten over the grazing duration.

At the same time pasture area is released to either accumulate feed for winter or improve the feeding of other animals. This is equivalent to an area of 4.25 ha of pasture for every 1 ha of crop grazed. 

Final grazing was programmed for late winter and anticipated 500 ewes/ha for 3 days at an intake of 2.2 kg DM/head/day totalling 3.3 t DM/ha with total feed used 7.87 t DM/ha. Estimated yield of winter crop to replace this is 7.87/0.85 (expected utilisation) equalling 9.25 t DM/ha.

Grazing multi-species forage mixtures will be successful if:

• The feed is utilised by the right stock at the right time
• Seed company recommendations are observed regarding maturity of crop, grazing cycles to maximise production and feed quality etc
• Forage is utilised before it dies
• Block grazing is employed, not strip grazing
• 2–4-day grazing periods used to lower instant stocking rate, reduce walking and settle stock
• Feed allocation is accurate – try using crop measurement and feeding apps (weekly calculations)
• Stock are moved if the weather is bad, returned later when paddock dries out. 

With the practice of wintering animals on forage crops common place New Zealand, AgResearch has been investigating different methods of grazing animals over winter to maintain farm returns and improve environmental performance.

A team of AgResearch scientists, led by Invermay soil scientist Dr Ross Monaghan, is investigating whether a pasture-based alternative, supplemented with hay or baleage, will reduce nitrate leaching and paddock pugging (mud). 

Below we have downloadable resources from the Ministry for Primary Industries wintering with less crops programme.