What you need to know when preparing for maize harvest
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- 4 Sep 2018
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Whatever the use and however much maize is going to be fed in the ration, optimising dry matter, starch yield and fibre digestibility is the key. The latter of the two being more significant, yet harder to measure.
Ultimately, we are trying to achieve the same goal as every other year- good quality forage, but considering the season and forage shortages in some situations, there may be some other considerations. When good harvest conditions are predicted, we should be able to get drier crops without sacrificing fibre digestibility. The mad rush to get the crop as late as you dare before the late Autumn weather gets hold, may not always be quite so frantic.
The cob may be fit to go, but the plant could still be green, or on the drought-stressed ground, the plant could well be very dry and fit to cut as soon as the cob firms up. Monitor crop dry matter, so you don’t get caught out. Aim for 32-35% DM with good starch and fibre digestibility that can be well compacted into the clamp.
Use the following steps developed by the Schothorst Feed Research Institute to determine when to cut:
1. Cob to plant ratio
This may have a more significant effect in years with shorter crops, where the cob is 60% of the dry matter, compared to 50% for a standard crop. Some crops with poor cob development, that are tall and with a high plant population, will be 40% cob. Ideally, take a selection of plants, pull the cobs off, cut the plant into manageable sized pieces and weigh them to get the ratio.
2. Estimate the DM of the cob
Select a few kernels from a range of cobs – not just the best looking ones. Cut lengthways and compare the table below.
| Stage | Cornel is... | DM content cob |
| Milk Ripe | White-yellow, with much tension, content looks like milk. | 35% |
| Soft dough ripe | Yellow, content partly dough, milk sprays when pressed with nail. |
40% |
| Soft to dough ripe | Dark yellow, half moist at the basis, other half is firm. |
45% |
| Dough ripe | Dark yellow, some moisture at the basis, rest is firm. |
50% |
| Hard dough ripe | Dark yellow, whole cornel is firm and difficult to press with the nail, no moisture, top of cornel becomes vitreous. |
55% |
| Fully ripe | Firm, cannot be pressed by nail, vitreous parts are as horn, black cork layer. |
60% |
3. Estimate the DM of the plant and leaves
Cut the surface of several plant stems and press on the soft tissue inside. Observe the juice that flows out and compare with the table below.
| Condition of stem and leaves | DM content plant and leaves |
| Whole plant is green and clear juice flow in the stem | 18% |
| Plant is green for 3/4, stems still have moisture | 21% |
| Plant is green for 1/2, stems almost dry | 24% |
| Plant is green for 1/4, stems completely dry | 27% |
| Plant is completely yellow, crop looks dead | 30% |
4. Condition of stem and leaves
Handboek Snijmais (2018) Wageningen University and Research:
From this, simply multiply then enter the figures into one of the calculations below.
- Cob/Plant ratio 60/40
(cobDM*0.6) + (plantDM*0.4) - Cob/Plant ration 50/50
(cobDM*0.5) + (plantDM*0.5) - Cob/Plant ratio 40/60
(cobDM*0.4) + (plantDM*0.6)
It is important to know the cob to plant ratio, as this can vary the whole plant dry matter significantly.
For farms feeding higher than normal levels of concentrates, ensure low levels of lactic acid, by getting the crop in above 32DM. All crops need an inoculant and compact, compact, compact in the pit, to retain the value of the crop. As soon as the crop is clamped, get a good estimation of stocks, to accurately budget for the forthcoming winter and into next year.
For further advice, please contact one of the Wynnstay Dairy Technical Services team, click here to meet the team.
Wynnstay Head of Dairy services, David Howard has over 12 years of experience in the ruminant feed industry following his graduation from Harper Adams University. His specialities lie in key areas such as robotic milking, lameness in dairy cows and transition cow management. As well as being a qualified Cow Signals Master Trainer, David has been a mentor for Farming Connect in the area of robotic milking systems.
