The decision on which supplement to include in your farm system should be based on the cheapest form of energy (i.e. cents/MJ ME). Infrastructure, storage, wastage, the logistics of feeding and utilisation of the supplement should all be considered in your comparison.
Supplements should have a better or similar ME to pasture (i.e. at least greater than 10.5 MJ ME/kg DM).
Details of commonly fed supplements including MJ ME, wastage and other considerations are listed below.
| Supplement | MJ ME/kg DM | Nitrogen content (%DM) | Estimated wastage feeding out | Other |
| Potatoes | 13.0 | 1.6 | 20%+ | High risk of acidosis. Need to restrict to 3kg DM/cow/day if fed in bins as risk of acidosis from cows gorging. Limited supply. |
| Meal | 12.5 (12.0-13.0). ME is dependent on the weighted ME of the ingredients. Where the meal contains mineral-based compounds, e.g. magnesium, the ME will be less than the weighted average of the feed ingredients | Refer to ingredient list and multiply the crude protein by 16% | 10%+ 5% pelletised Wastage is dependent on the processing of the meal (pellet vs loose) and how it is fed (in-shed feeding vs out of shed feeding in troughs) 0hV1 |
Moderate to high risk of acidosis (depending on feed ingredients). Need to introduce slowly and feed so individual cows can't gorge. Can get intakes of up to 3kgDM per cow per feed. |
| Molasses | 12 | 0.6 | 10-15% | High risk of acidosis. Max intake 1.0-1.5kg DM/cow (i.e. 2 l/cow). Introduce gradually. |
| 25% Tapioca; 75% PKE | 8.45 (tapioca 3.2, PKE 8.25) | 1.98 (tapioca 0.3, PKE 1.68) | Fed in bins 10-20%, fed in paddock 30%+ | Moderate risk of acidosis, especially if poorly mixed. Reduced by minimising Tapioca to 25% of mix and good feed management (refer Farmfact Tapioca - 1-70). |
| Palm kernel | 11.0 | 2.2 | Fed in bins 10-20%, fed in paddock 30%+ | Not very palatable. Needs to be available to cows when grazing to encourage intake when first introduced. Ideally no more than 30% of the diet; severe feed deficits max intake 50% of diet, balanced forage. Cows need water all day at high intakes. No major animal health risks. At high intakes review copper supplementation (refer Farmfact Palm kernel extract - 1-71). |
| Silage/baleage |
9.0-10.0 |
2.4-2.7 |
20%+ | Silage and baleage often not 10.5 ME and therefore not suitable as milking feed. Suitable feed for dry cows, or if no long-chop feed available for milkers (to reduce risk of acidosis). Cost varies depending on size of bale, wastage and ME. |
| Maize silage | 10.0-11.0 Average 10.3ME |
1.3 | 20%+ | Ideally no more than 30% of diet to avoid amino acid and protein deficiency; feed up to 40% of diet for milkers and 50% of diet for dry cows if pasture 25%CP. At high intakes require supplementation with Ca, Mg and Na. |
| Cereal silage | 8-11 | 20%+ good quality, 30-40% poor quality | Like maize, not all regions in NZ suited to growing quality cereal silage and to get high ME crops requires top management (small harvesting window). Can get high wastage if poor quality) | |
| Hay | 8-9 | 1.1-2.7 | 20%+ | Suitable feed for dry cows, or if no long-chop feed for milkers (to reduce risk of acidosis). |
| Straw | 6.3-6.7 | 0.6-1.0 | 20%+ | Not suitable as milking cow feed but can make part of a dry cow ration. Maybe required in diet to meet fibre requirements, esp. if diet high in sugar/starch and little long chop silage, hay or pasture available. |
| Onions | 13 | 1.9 | 20%= | Feeding may cause anaemia, cows may also choke and risk of milk taint. |
| Kiwifruit | 12-12.5% | 1.0-2.7 | 20%+ | Intake must be increased gradually over 2-3 weeks. Up to 3kg DM/dry cow/day (15 kg fruit/cow/day) can be fed to dry stock but this needs to be reduced to 5kg fruit/cow/day if the fruit is ripe. milking cows have been fed up to 5-6kg DM/cow/day without obvious problems but only where cows have a high intake of pasture (10-12 kg DM/cow/day). As kiwifruit is high in soluble sugars there is a high risk of acidosis when fed to excess. There is also a risk of animals choking especially when fruit is hard. |
| Note: Starch-based concentrates (e.g. grain, tapioca) | When feeding a starch-based concentrate, the ME of pasture decreases by up to 5% due to negative associative effects in ruminal fibre digestion. |
