The main issue with fodder beet is rumen acidosis and the consequence is often a slower transition period than to kale. When the winter period is already short and body condition score (BCS) gain often required, the length of the transition is often seen as a weakness. Using fodder beet as a whole farm approach, where the cows are transitioned on to fodder beet on the platform in late autumn – often as a substitute for maize or whole crop silage – is proving to be successful.
Two challenges with wintering on fodder beet are:
1. Transitioning cows from a grass diet to fodder beet.
2. The accurate allocation of fodder beet to avoid nutritional disorders such as rumen acidosis.
Transitioning is allowing time for the rumen microbial populations to reach equilibrium capable of dealing with a new feed. Theoretically this process takes 21 days to complete. Onfarm evidence suggests a gradual introduction to fodder beet over three to four weeks reduces the risk of nutritional issues such as rumen upset. From a practical perspective, this can be achieved by introducing fodder beet to the autumn milking ration by including an area to be grazed in-situ on the milking platform, or by lifting a small area and feeding out
When transitioned well over a three-week period the risk of acidosis is greatly reduced.
Clinical symptoms of acute rumen acidosis include depression, dehydration, scouring, bloating, laminitis, rumenitis, milk fever and sudden death. Often there are no specific clinical signs of rumen acidosis. Many cases of cows that “don’t do well” on fodder beet (empty gutted, condition loss), especially during the first 2-3 weeks of feeding, are actually sub-clinical cases of rumen acidosis.
When introducing fodder beet to cows in late autumn the transition is almost a natural process and not a crash change, as happens when changing from grass to winter crop at drying off.
Allocations of fodder beet to cows during late autumn, when lactating, should start at 1kg drymatter (DM)/cow, increasing at 0.5kg DM/cow/day to a third of the diet.
Careful observation of all cows is necessary. If any cows appear unwell, they should be moved to pasture.
The key points for considering fodder beet as a late autumn feed are:
- Very high yield potential, enabling smaller areas to be cropped, therefore less strain on rotation
- Consistent high-energy feed
- Highly palatable and digestible for ruminants
- Because it’s not a brassica, clubroot and dry root are not an issue
- Ease of feeding because of lower height.
- Potential to lift and feed – easy storage
- Relatively low nitrogen requirement – potentially positive environmentally
- Often provides a greater gross margin than other winter crops
- Cheaper growing cost than silage or maize
- Graze in-situ and the ability to lift and store.
The obvious opportunity cost of planting fodder beet on the platform is losing that area to grass for milk production. However, this opportunity cost is often mis-interpreted and not as big as expected. The fodder beet will often out-yield the previous pasture in kg DM/ha and is still converted to milksolids in autumn.
Using conservative yield expectations of fodder beet at 16t DM/ha – grazing from mid-late April and using Farmax to model the financial outcomes of planting 5% of the platform area into fodder beet to allow for intakes at 1kg DM/cow increasing to 3kg DM/cow for a six-week period – and substituting for previously purchased maize and whole-crop silage, Farmax estimates a lift in profit of $130/ha at a $6/kg milksolids. Profitability lifts at lower payouts as the opportunity cost from lost pasture is less, and conversely profitability is reduced at higher payouts.
Profitability from planting and grazing fodder beet on the platform in the autumn is influenced by yield, growing costs and the cost of substituted feeds such as grain, maize and whole-crop silage.
Autumn lactation from fodder beet has become common practice for many dairy farms with many additional benefits reported:
- Cow BCS through autumn improved, with BCS on a continual rising plane from autumn through winter. There’s no check as cows are transitioned to winter feeds.
- Better BCS cows at calving and all the associated benefits of better in-calf rates and improved milk production.
- Extended days in milk with improvement in autumn covers. It’s easier to push out the autumn round when grazing fodder beet.
- Using high potassium levels from effluent paddocks. Fodder beet is a gross feeder of potassium and has a high requirement for yield.
- High yields have also been utilised for winter grazing, although this should always be considered against the current nutrient consents and nitrogen loss to water. Modelling through Overseer is advised.
Key points
- Fodder beet can be grown on platform without compromising milk production.
- Fodder beet is a great way to re-grass. The re-grassing result will be far superior than grass-to-grass.
- Farm costs won’t be at the whim of the feed markets.
- BCS gain on fodder beet at least as good as maize.
- Time required for both options is similar.
- Fodder beet can be challenging in wet weather, but maize utilisation in these conditions can be also poor.
