Prepare Now for Corn Harvest

We are now four or five months away from corn silage harvest, so this might be a good time to conduct training and plan in order to maximize the value of your corn crop.

Through training, we can achieve an educated and motivated crew that has an enthusiastic and organized approach to the common goal of producing high-quality corn silage that will maximize milk production while minimizing grain costs.

We can use HACCP (hazard analysis critical control points) to educate, motivate and organize the farm crew to achieve our common goal. In practice, we can use HACCP to measure different critical control points and if a critical control point is out of range, implement corrective actions to achieve our forage quality objectives.

The following six points define what we are looking for with regard to quality corn silage.

1. Harvest the corn plant between 32% and 36% dry matter to ensure good digestibility and facilitate packing and quality fermentation. Silage harvested under 32% dry matter loses too many nutrients through liquid shrink. Wet corn silage also dilutes the acid, and as a result it takes longer for the pH to drop. This extends the aerobic fermentation phase, allowing bad organisms to keep growing longer.

The bottom line is silage that is too wet hurts the fermentation. Silage piles over 36% dry matter are hard to pack, so it’s difficult to extract all the air. Plus, these silages are typi- cally over mature and have lower digestibility: the older the plant, the more lignin.

2. Harvest the plant with a target milk line of 75% and a minimum milk line of 50%. This is an indicator of starch deposition into the kernel. As sugars are converted into starch and deposited in the kernel, the milk line increases. The more milk line we have, the less corn grain we will have to feed to reach adequate total levels in the diet. Monitor the milk line closely—as it increases, the plant gets drier.

3. Attain neutral detergent fiber digestibility at 30 hours of >45%. Fiber digestibility is possibly the biggest influence over how much corn silage you will be able to feed and how cows will milk on dif- ferent quality corn silages. Lower digestibility numbers decrease feed intakes and impair cow performance. Here are tips to improve silage digestibility:

• Choose corn varieties that have a high fiber digestibility.
• Plant corn as early as possible to minimize plant growth during hot weather.
• If irrigating, irrigate more often with less volume. Do everything to get water to the entire field as quickly as possible.
• Harvest plant at the desired dry matter range.

4. Achieve optimal corn silage pro- cessing scores (CSPS) of 70% or greater. Starch digestibility in corn silage might vary between 60% and 85%. Processing the kernels increases how much of the total starch is available to the cow. Processing score, together with total starch, will define how much rolled corn you will have to supplement. Optimal processing makes more of the total plant starch avail- able to the cow.

5. Reach anaerobic fermentation and drop the pH of the silage pile as quickly as possible. The pH should drop below 4 to prevent pathogen growth. Lactic acid is what makes silage pH drop rap- idly, minimizing yeast, mold and undesirable bacteria growth during initial fermentation.

The goal is to reach a lactic to acetic acid ratio of 3:1. Lactic acid drops the pH of the pile and acetic acid prevents the pile from heating and halts bad yeast and mold growth.

6. Prevent air from getting into the silage pile until it is opened to feed. After we put up the pile and cover it and the little bit of oxygen that we couldn’t extract is used up, we halt aerobic fermentation. We do not want oxygen to get back into the pile and restart aerobic fermentation, which is called secondary fermentation. This secondary fermentation is a major cause of shrink and money down the drain.

Together with secondary fermentation comes a rise in pH, heating up the silage and the growth of badbacteria.Pilesurfacetemperature,asmeasuredwith an infrared thermometer, should be equal or below ambient temperature.

So let’s get organized, train all personnel involved with making high-quality silage and create a comprehensive game plan to make sure we hit all our critical control points to get the most out of our precious home-grown forages. This will help us maximize production and minimize grain cots. 

I’d also like to extend a thank you to Lance Whitlock and Luciana Jonkman for your valuable contributions to this article!

To help you train your employees on these important factors, we’ve created two PDFs for you to download:

• The first PDF is the six points outlined in this article.
• The second PDF is an explanation of how to achieve and monitor each of these six points. 

Enrique Schcolnik is a dairy nutrition consultant with Progressive Dairy Solutions. His work emphasizes improving overall herd health and production through sound ration design and proper implementation.

Note: This story appears in the May/June 2018 magazine issue of Dairy Herd Management.