Forage harvesting spring 2011

To say it bluntly, this weather is for the birds! At a time when forage supplies are becoming low and producers look toward spring harvests of winter small grains and cool season grasses, these unending rain events are seriously affecting dairy and livestock producers. In travels across south-central PA last week there were significant acres of ryelage, mowed at the perfect maturity, laying in windrows getting rained on from unexpected showers and in many locations, significant rainfalls. Tedders and rakes were out trying to quickly get the forages dry enough for harvest ahead of the next rain event. Even without the additional rain the weather sure has not been favorable for ideal forage harvest.

Highest levels of forage quality and quantity are found immediately at mowing or grazing. Graziers manage their animals to direct harvest, reducing losses that start immediately upon mowing. When forages are mowed the plant continues a natural process called respiration until the whole plant moisture drops to 15% or ensiling lowers the pH to less than 5.0. During this time the plant is using stored carbohydrates (sugars) in the plant cells for the respiration process. When consuming these sugars the plant loses dry matter and quality. Speedy dry down is important to minimize these losses. If the forage is rewetted during the dry down process additional sugars will continue to be lost causing significant losses for forage quality and value.

Rain also causes leaching of plant cell nutrients by washing out soluble plant cell components such as carbohydrates, proteins and minerals. Not only are these soluble nutrients important for forage quality for livestock, they are vital for optimum fermentation by haylage bacteria during the ensiling process. Plant sugars are the food source for these beneficial bacteria. Forages that remain in the field for an extended time or have been exposed to significant rain before chopping or baling will not complete an optimum fermentation. These forages will not store well for longer periods and will present feeding challenges. Having good estimates of forage quality by using frequent forage testing will be important throughout feedout.

In many locations rye is still standing and quickly maturing. Feed value of these forages is reduced as the plant rapidly increases the amount of poorly digested, higher lignin in plant stems. The challenge is always to time harvest for highest quality (boot stage) and then get the forage mass dried down to chopping moistures as rapidly as possible without environmental conditions that result in excessive nutrient losses. Easier said than done, in 2011.

Source: Paul Craig, Penn State Extension, Dauphin County