Cutting rye to winterize seems a smart choice especially on non-drought prone soils, but what do we want with it?
For dairy cows
Some dairy farms want to use cut rye primarily as a protein gainer in a corn-rich base ration for dairy cows. They have every interest in solid N fertilization in the spring and an earlier early leafy cut.
Thus, we can arrive at solid feed values of a feedstuff with which we can milk smoothly:
| DS | VEM | FOS | DVE | OEB | RE | RC | ZET | SUI | VET |
|---|---|---|---|---|---|---|---|---|---|
|
35% |
950 |
550 |
70 |
55 |
175 |
220 |
0 |
75 |
40 |
The associated growing characteristics of cut rye harvested early:
At a yield of 3.8 tons DS/ha at 17.5% RE, it yields 665 kg of protein and thus needs at least 106 kg of active nitrogen in spring. At a nitrogen content of 4.8 kg per tonne with a coefficient of action of 60%, an early slurry application of 25 tonnes per ha would yield only 72 kg of active nitrogen. Thus, the crop will still need at least 126 kg of KAS brought to the field in a timely manner.
In short, to grow dairy cow fodder, we need to provide nitrogen in a timely and ample manner even for spring rye. Even now fertilizer is expensive. Witness the fodder value price (273 €/ton DS) which is double the cost price (136 €/ton DS) when fertilizing properly
For dry cows or young stock
Other farms may have enough protein-rich grass or grass-clover on the farm and are more likely to seek dry cow or heifer forage. Then the message is to harvest later, looking for more dry matter per ha with lower protein content.
| DS | VEM | FOS | DVE | OEB | RE | RC | ZET | SUI | VET |
|---|---|---|---|---|---|---|---|---|---|
|
27,5% |
825 |
564 |
38 |
-15 |
90 |
335 |
0 |
55 |
35 |
The associated growing characteristics of cut rye late harvested:
With the same fertilization, we arrive at a much wider yield of 7.38 tons DS/ha with a much lower protein content of 9% and a much higher crude fiber content.
As a basis for a ration for dry cows, this can serve provided protein supplementation to at least 12% RE for the entire ration. Depending on the growth phase, the young cattle will also need to be fed a protein content of at least 12% for rather extensive rearing or 13% for intensive rearing. Moreover, in the early juvenile phase, the protein requirement of intensive young cattle is up to 16-17%RE and in further gestation also 14-15%. In all cases a protein correction will be needed, this can certainly come from a less well preserved (autumn) grass silage from one year of age onward with which we cannot get to the dairy cows.
PS: in Farmdesk you can also calculate rations for young cattle and dry cows, more info in this article.
Summary
Cutting rye can be used widely and diversely on a dairy farm. You do need to know before harvest what you want to do with it during the feeding season.
Furthermore, I think that a heavier crop could be perfectly fine on a well-moisturized soil, while we better opt for the quicker harvest of a leafy crop with a lower dry matter yield on a drier soil so as not to over-hypothecate the subsequent corn crop in terms of moisture supply during the growing season.
