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3 open minutes with Deb Wilks

Published on 01 October 2018

Deb Wilks is a dairy nutritionist and consultant with EPL Feed LLC, a nutritional support and service team for dairy producers in the Pacific Northwest.

She presented at the 2018 Northwest Hay Expo in Kennewick, Washington, on alfalfa in dairy rations. These questions are a follow-up from her presentation.

Q. It’s no secret corn silage leads the pack as the main forage for dairy rations; can you explain why that is?

Wilks: Corn silage is high in energy and, if ensiled at the right dry matter, processing score and pack density, the NDF (neutral detergent fiber) and starch are highly digestible and available in the rumen. Ruminal starch provides fuel for fermentation and the production of energy and amino acids for the cow.

New varieties of corn silage with improved genetics have shown increased digestibility of NDF and starch.

In addition, the nutrient content of corn silage is very consistent across various fields compared to other grasses and alfalfa. Cows eat corn silage very well, and transitioning onto higher-corn silage rations is not usually a problem.

Ration costs are typically lower because of lower purchased feed inputs from fewer ground corn purchases. Income over feed costs over time is higher on high-corn silage rations because of lower costs and higher milk production.

Q. Could alfalfa hay ever replace corn silage in the number one spot?

Wilks: Although alfalfa hay does play a very important role in many dairy rations, corn silage is ideal as the main forage for the above reasons. Although there are exceptions, high-alfalfa hay rations tend to be more inconsistent and lower in digestible starch needed by the rumen.

Ration costs tend to be higher, as more purchased corn or barley is needed. There is a reduction in purchased protein cost with high-alfalfa ration, but this doesn’t compensate for the increase in overall grain costs from the lack of digestible starch.

Q. What nutrient tests should growers be using to analyze their hay?

Wilks: Analysis for various nutrients is very important to help determine quality of alfalfa and other forages. Dry matter, protein, NDFom (ash free), NDF digestibility and ash are the most important analyses used to evaluate forage quality for alfalfa.

Although there are several calculated values that help provide scales for comparison, the actual nutrient analyses are the most important numbers to communicate to dairy customers and nutritionists.

Q. Why isn’t alfalfa valued higher for its protein content?

Wilks: Comparing cost per unit of crude protein for sources commonly used in dairy rations, other ingredients are usually cheaper. For example, canola contains 42 percent crude protein on a dry matter basis and, at $300 a ton, alfalfa hay would have to be $140 a ton at 22 percent crude protein to equal canola on a cost-per-unit-of-protein basis.

Obviously, as the price of canola drops, the equivalent price for hay would be lower. Although alfalfa is a forage and can provide other nutrients and benefits besides protein, these estimates are used to price alfalfa hay into rations based solely on protein.

Q. When is alfalfa used in the ration?

Wilks: Alfalfa hay can be an excellent addition to the ration depending on several factors. It will be incorporated as dairy producers need more forage, and when a longer-stem forage is needed to provide effective fiber for the rumen. Some rations high in wet silage also benefit from more high-quality alfalfa hay.

Q. Why hasn’t more alfalfa hay been used in the last few years due to low hay prices?

Wilks: Even though hay prices have been lower in the last few years, all other commodities and forages have also been lower, along with milk price. More recently, commodities have rebounded up, and projections for 2018 hay prices are also expected to be higher. Inclusion of more alfalfa hay into dairy rations depends on its relative value to other protein and forage sources.

Q. Consistent rations are important for animal health and quality of milk; what advice do you have for growers to help dairy producers maintain that consistency?

Wilks: Whenever possible, cut fields quickly and simultaneously. Although weather conditions will have an effect on growth, a consistent cutting window helps to ensure consistent quality hay. Blending hay of different cuttings or fields is a good method for diluting changes in hay quality and is a common practice on dairies.

A sample analysis from each load before it’s fed helps to avoid abrupt changes for cows. The nutritionist can adjust rations to keep nutrients more consistent.

Q. What issues or opportunities should alfalfa growers be aware of going forward?

Wilks: Long periods of low milk prices increase the awareness of feeding efficiency and, therefore, forage quality. Cows that are not healthy and not producing milk and milk components at optimum levels are detrimental to the survival of dairy herds in these times.

Alfalfa hay can play an important role in dairy rations, and with more focus on NDFom, NDF digestibility and consistency, alfalfa will become more relevant for dairies. Hay growers, dairy producers and nutritionists should work together using the same language to ensure the best balance of forages in the rations.  end mark