There is no doubt that corn silage, barley silage and alfalfa haylage are the major fermented forages supporting the dairy industry in Canada and the US. Any variation in the nutrient composition and digestibility of these forages will therefore directly affect a producer’s ability to meet their dairy cows' nutrient requirements throughout the year.
In other words, a good understanding of the nutritive value of your fermented forages will allow you to develop a nutrition program that helps your cows reach their true genetic potential for milk production and health.
More nutrients for the cow, more dollars in your pocket
Over the last few years, nutritionists and dairy producers have been paying special attention to the nutritive value of fermented forages. It is now widely acknowledged that this nutritional concept can positively impact animal productivity and producer profitability. The performance of the modern dairy cow is highly dependent upon the adequate levels and favorable balances of nutrients in the fermented forages they consume.
It is an oversimplification to define the nutritive value of fermented forages purely as the ability to supply the nutrients present in the dry matter to the cow. Before nutrients can reach their target tissue in the cow, the feed must be consumed (feed intake) and the nutrients in the forage must be released and absorbed by the cow (digestion).
When it comes to digestion, fermentable forages are a step ahead
Many factors influence the nutritive value of fermentable forages, including forage cultivar, stage of maturity at harvest and storage methods. In contrast to non-fermentable forages, the digestion of fermentable forage begins long before it is added to the feed bunk.
During normal ensiling processes, some nutrients ferment, releasing molecules that make the crop more palatable and easier to digest. Under these conditions, the nutrients have a better chance of being ingested and absorbed.
Practically speaking, this fermentable forage has an optimum nutritive value. In commercial dairy herds, this forage will result in high milk yield and milk components, leading to excellent reproductive performance and good health.
Test your forage to see how it measures up
Usually, producers and nutritionists send forage samples to a lab in order to obtain information on the nutritional composition of the fermented forages. However, this information can come up short in terms of allowing producers to understand how available these nutrients are to the cow.
Fortunately, methods such as Alltech’s In vitro Fermentation Model have been developed to efficiently and quickly determine the nutrient availability in these forages, including the neutral detergent fiber digestibility (NDFD), or the organic matter digestibility. Results from these tests are positively correlated with potential intake. When this information is analyzed as a whole, producers can get a good idea of the nutritive value of their fermented forage.
In Ontario and Quebec, a recent survey carried out on 47 fermented forages indicated that over 84 percent of the forage samples collected showed NDFD (at 30 hours in vitro) values below 52 percent, suggesting poor nutritive value. Therefore, it is important not to assume that your forages have a good nutritive value. To assure herd performance, testing is a must.
Reviewing the nutritive value of the fermented forages used in any feeding program is essential to help your dairy herd reach its maximum genetic potential and is an integral part of dairy farming profitability.