A fibre source such as baleage, silage, hay or straw, is required to make the cows feel full for longer so they don’t wander the paddock looking for feed once all the crop is consumed.
Determining feeding levels
Consideration to the amount of crop and supplement to feed should be given to the balance of nutrients that the diet will provide and the rate that the crop can be consumed.
Feeding levels of all crops should be determined based on the energy requirement for maintenance, pregnancy and the body condition score gain required during the winter period.
Pros and cons of the two winter feeding systems
Generally, if the diet contains at least 30% pasture silage/baleage the risks of nutrient imbalances will be reduced. Fodder beet systems have evolved to where beets are offered to appetite with reduced amounts of supplement.
70% crop with pasture baleage or silage
Fodder beet to appetite with straw or silage
- Easier to differentially feed mobs for BCS gain
- Higher crude protein intake
- Lower cost winter diet
- Reduced risk of acidosis if breakouts occur because cows are not hungry
- Easier to allocate crop in paddocks with uneven yield
- Higher cost
- More challenging to accurately allocate fodder beet each day in paddocks with uneven crop yields
- More risk of acidosis if total DMI is restricted and cows break out or the paddock yield is variable
- Potential for more over conditioned cows at the end of winter
- Cows on a very low crude protein diet, especially if the supplement is cereal straw
- Lower mineral intake
Factors to consider
- Fencing to control breakouts
- Crop allocation in paddocks with variable yield
Factors to consider
- Managing high body condition score cows
- Protein intake, especially with growing cattle.
Transitioning steps for non-lactating cows
- Strict allocation of fodder beet on a DM basis over a period of at least 14 days is essential.
- Allocation should start at 1-2 kg fodder beet DM and increase by no more than 1 kg DM every second day for 14-21 days – i.e., up to a maximum of 9-10 kg DM/cow.
- If ad libitum intake is the target, from day 21 the break line is then increased a little each day until the cows leave fodder beet behind.
- Supplement/pasture inputs need to provide the additional energy to meet cow requirements, so start at 8 kg DM on day 1 and drop to 4 kg DM by day 14; then 2-4 kg at day 21 and thereafter.
- Even if cows have been consuming fodder beet during lactation they still require additional transitioning up to their winter allocation, using the 1 kg DM every second day approach (e.g., if feeding 4 kg DM during lactation and through the drying off period then on day 1 of winter transitioning offer 5 kg DM, day 3 offer 6 kg DM, day 5 offer 7 kg DM etc.).
- A strategy is required to deal with the 10-20% of animals that may not consume fodder beet during lactation. These are the at risk cows in the early stages of transitioning.
Low protein intake on winter fodder beet diets
- Fodder beet bulbs are very low in crude protein i.e. 7-8%
- The protein content of the whole plant will be dependent on the leaf:bulb ratio and also the crude protein content in the leaf.
- Many winter fodder beet diets (“ad lib” fodder beet plus cereal straw) will not be meeting the 10-12% diet crude protein recommendation for non-lactating cows.
- While it is widely accepted that ruminants can survive on low protein diets because dietary N is converted to microbial protein, which is then used by the animal, the rumen microbes still require N to produce microbial protein. In several experiments rumen ammonia concentrations have declined to very low levels 6-8 hours after feeding and remained low until the following morning. The impact of this on production and health requires further investigation.
Fodder beet wintering and environment
Leaching losses measured following grazing of fodder beet crops on light stony soils at Ashley Dene, Canterbury, were 50-60 kg N/ha. Comparative losses from kale crops on the same soil type were 60-80 kg N/ha.
Lower losses are observed with fodder beet because of the low crude protein (nitrogen) in the crop and therefore less nitrogen is deposited in the urine patches.
This does not mean good management should be ignored. Implementing good environmental management practices on-farm is not only efficient – it helps to minimise risk to your business and reduce your environmental impact.