Anita Fleming, Ph.D. Candidate, Lincoln University
Fodder beet can be fed at times of pasture deficit. It provides high yields of highly digestible nutrients but there are animal health risks, particularly acute and sub-acute rumen acidosis (SARA). Fodder beet is expensive to establish and harvest, but can have high yields. It needs 200 growing days, giving a 15 month cycle grass to grass. In comparison maize silage costs less to grow, has a shorter rotation (6 months grass to grass) and has a lower animal health risk.
Four feeding options were compared using a detailed Sharpes ratio analysi:
- Maize silage that was forward contracted and imported, fed in early (June to September) and late (March to May) lactation.
- Home grown maize silage fed at the same time as 1.
- Fodder beet grazed March to May and fed August to November
- The same fodder beet feeding programme but accounting for animal health consequences (1% stock fatality at each transition and 5% reduction in pasture intake due to impaired rumen health).
The analysis showed that when crop rotation is accounted for, growing and feeding maize silage was more profitable, and carried less risk, compared to growing and feeding fodder beet. There is also more flexibility to store and feed maize silage later if there is a greater yield than expected.
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