No substitute for quality forages

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Somehow, milking cows this year is not as fun as it was at this time last year. Margins have shrunk considerably and the profitability of many farm operations is questionable.

Many times, improvements in cow productivity can be a real benefit to a farm’s bottom line. Many companies offer productivity-enhancing products, many of them good, some of them questionable.

The one thing that nobody can sell you is top quality for the forages produced on your own farm.

Forage quality has a huge effect on your cows’ health and productivity and is arguably the single most important physical factor to dairy profitability.

It is also something that is mostly under your control. Being close to the first cut of your hay crop, I will concentrate on making quality hay crop silage (a.k.a. haylage) in this column.

We will look at corn silage quality at a later time.

Stage of maturity

It doesn’t matter whether the crop is made predominantly of legumes or grasses, the stage of maturity at harvest is the single most important factor affecting quality. Plants were never really designed to be eaten.

During their first stages of growth, grass and legume plants concentrate on building up their energy factories. These are the leaves, which are designed to capture the solar energy necessary for their growth.

Most leaves are highly digestible and nutritious to dairy cows. Following this initial stage, plants concentrate on building up their structure (stems) and reproductive organs. In trying to rise above their neighbors in an attempt to catch more sun rays, plants have to build rigid structures that contain a lot of lignin.

Lignin is what a log of wood is primarily made of; it is of no nutritional value to a cow. So, it is important that the crop be harvested before the plant has much opportunity to make much lignin.

This would be late vegetative stage for both grasses and legumes.

Losing value

Using cold season grasses as an example, dry matter (DM) digestibility is generally close to 80 percent in the first few weeks after growth initiation in spring. But thereafter, DM digestibility drops by 1/3. Put differently, the crop looses more than 1.5 percent of its economic value for each day that harvest is delayed after the early vegetative stage.

Think of it as an additional 1.5 percent tax per day!

Moisture

A good fermentation requires that plant material be in a certain moisture range. For concrete tower silos, the ideal moisture is in the 50 to 60 percent moisture range. For horizontal, bunker silos, the ideal range is 62 to 68 percent moisture.

Soil contamination

Avoid soil contamination during harvest. Beside being completely undigestible, soil particles can carry clostridium species. Many clostridia produce nasty toxins that can sicken and even kill your animal.

Tetanus is caused by a species of clostridium. Enough said.

Loss of leaves

Avoid rough treatment of the crop when building windrows. The loss of leaves not only affects yields, but the most digestible parts are being lost.

Rain

Mind you, you have no control over when it rains, but you have some control of when to harvest in relation to weather forecasts. Rain during field curing has a devastating effect on forage quality.

In one experiment with alfalfa, the plant material that was harvested without rain had a DM digestibility of 72 percent. A 1.6-inch rainfall during curing reduced DM digestibility to 58 percent, while a 2.4-inch rainfall reduced DM digestibility to 45 percent (or about the digestibility of a good wheat straw).

Packing

A good lactic fermentation is anaerobic — without air (oxygen). It is thus important to remove air from the pile as quickly as possible after its delivery to the silo.

This means aggressive packing.

Covering

If packing is done correctly, you must ensure that air doesn’t get in the silage later on. To keep air out, bunker silos have to be covered with a plastic cover. Understandably, this is a nasty job, one that I don’t want to volunteer for.

Just buy some beer and/or ice cream for the “volunteers” for when the job is finally done.

Inoculant

This is something that someone is selling you, so it is tempting to think that maybe you can get by without an effective inoculant. If you think so, then maybe you should give away 5 percent of your haylage crop to your neighbor, because that’s how much silage DM is being saved on an average by an effective inoculant.

Time

Like a good spaghetti sauce, you must let the silage “cook” long enough. Starting to feed the silage too quickly after ensiling can result in production disasters.

A good rule of thumb is to let it cook for a minimum of two months.

It is easy to recognize nutritionists who had to deal with low quality forages on a farm: they are bald from pulling their hair out!

There is nothing that can be done to make a poor quality forage behave like a high quality forage in a cow.

There is no magic powder, no fu-fu dust, and no magic incantation that can substitute for forage quality.

And forage quality is something that can be managed.

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