PGG Wrightson Seeds vet Charlotte Westwood says while fodder beet can be a valuable feed crop for wintering a large number of ewes within a small area, there is unlikely to be sufficient leaf available on fodder beet to meet the protein requirements of heavily in-lamb ewes.
Speaking at a Beef + Lamb New Zealand field day earlier this year, Charlotte says while the leaf on fodder beet crops contains 22-25% protein, by the end of winter, most of the leaf has typically disappeared. In late pregnancy ewes require 16-18% protein and yet the protein in the bulb only contains 7% protein.
In absence of a protein-rich supplement – for example, top quality pasture or lucerne baleage - ewes will mobilise their own protein reserves which may result in low birthweight lambs. Ideally, ewes should be off fodder beet and set-stocked back onto pasture four weeks pre-lambing.
Another issue with fodder beet is that it contains low levels of phosphorus. To compensate, phosphorus is pulled out of ewes’ bones which, over consecutive years, may cause metabolic issues.
She says caution is required when transitioning ewes onto fodder beet, particularly if crops are grazed in the vital 21-days after mating. The ewes should be eased onto the crop carefully and have access to good quality baleage. Ewes should be given two-days breaks on fodder beet to ensure they are getting sufficient protein through the leaf and bulb.
Similarly, ewes should be transitioned off fodder beet crops gradually, ideally onto strip-grazed pasture.
Even dry hoggets require a diet containing 12-14% protein and while their dietary requirements will be met if the leaf is healthy, if the leaf is decayed they will require a protein-rich supplement to avoid sub-optimal growth rates.
Feeding fodder beet to pregnant ewes: This new fact sheet summarises AgResearch research findings of feeding fodder beet to pregnant ewes, as well as guidance on protein requirements and grazing.
- Download fact sheet (PDF, 219KB)