Silage Corn: High Cut or Low Cut?

Kukurydza na kiszonkę: wysokie czy niskie cięcie?

Higher mowing means a greater share of cobs and grain in the yield, and lower mowing means a higher share of stems and leaves – higher starch content and lower fiber content – higher energy value
Lower mowing means more forage harvested – a greater "return" per hectare of corn cultivation

Corn Silage Mowing Height: Recommendations and Modifications

Determining the height of mowing corn for silage is a search for a compromise between the share of vegetative and generative parts of plants in the silage, and thus a search for a compromise between the quantity and quality of the produced feed. The stem and leaves, i.e. the vegetative parts, contain a lot of fiber; the cob filled with kernels is in turn a source of starch.

Corn farmers and growers can be divided into two groups in this respect. The standard, most frequently recommended approach considers harvesting corn for silage at a height of 15-25 cm from the ground as optimal, but lower cuts are also practiced. The second group considers such harvesting too low and practices high mowing, at a height of approx. 40-60 cm from the ground.

Cutting too low can contribute to contamination of the material, and thus to a deterioration of the durability of the silage. Low harvest means that a greater amount of lower parts of the stems, which have little nutritional value, end up in the feed. It is often the lowest parts of the plants that are most heavily infected by fungi, which increases the risk associated with the presence of mycotoxins in the feed. In turn, harvesting at a high altitude means that we collect less feed, the yield is lower, and a large part of the green mass remains in the field, which is considered waste by many farmers.

Supporters of lower corn cutting justify this primarily with the need to feed cattle and obtain an appropriate amount of feed for this purpose, especially in dry years, when the real problem is the shortage of feed on the farm. They argue that the low level of starch and lower energy value in silage can be easily and cheaply compensated for with appropriate additives. It is also pointed out that the higher fiber content in low-cut silage has a beneficial effect on chewing and salivation.

In turn, supporters of high mowing cite the higher quality of the feed obtained in this way as the crowning argument. This is the effect of increasing the share of cobs (grains) in relation to leaves and stems, thanks to which the silage has a higher energy value. Such feed is excellent for cows in the initial phase of lactation and its peak. More milk can be produced from 1 ton of silage from high cutting than from 1 ton of silage of low-cut corn. However, caution is recommended in the case of cows at the end of lactation and dry cows and heifers. High harvest is recommended in the case of strongly grown plants, where the proportion between the produced mass of leaves and stems and cobs is unfavourable.

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Corn silage cutting heights – results in numbers

An interesting comparison of the value of corn silage depending on the harvest height was made by Dr. Hab. Zbigniew Podkówka from the Jan and Jędrzej Śniadecki University of Technology in Bydgoszcz. The studies examined two cutting heights – 20 cm and 40 cm.

High-cut silage contained less crude fibre and total protein, and more dry matter and starch than low-cut silage. Green matter yield was significantly reduced in the case of high cutting, while in the comparison of dry matter yield the differences were smaller (due to the higher dry matter content in the high-cut material).

Milk production from one tonne of maize silage cut higher was 30 kg higher than in the case of low-cut maize, however, in terms of milk production from one hectare of maize, low cutting is more advantageous due to the greater amount of fodder obtained.

Parameter Low mowing (20 cm) High mowing (40 cm) Dry matter in silage (%) 29.89 31.99 Total protein in silage (% DM) 7.37 6.67 Crude fibre in silage (% DM) 24.79 22.30 Starch (% DM) 27.29 29.02 Green matter yield (t/ha) 69.6 61.2 Dry matter yield (t/ha) 20.8 19.6 Milk production per tonne of silage (kg) 451 481 Milk production per hectare of maize (kg) 28 235 26 497

Source: Podkówka 2019