Back High-quality pasture silage close in feed value to original pasture

Date: 30 August 2018

When there isn’t enough pasture to optimally feed cows, high-quality pasture silage is a valuable tool to increase milk production and condition score gain.

In fact, when it’s made right, high-quality pasture silage is a great source of energy and protein for a milking cow. It can also be used as a fibre source when feeding high-sugar or starch feeds.

However, that’s when it’s made right. Unfortunately, not all pasture silage is created equal.

The stark difference between feeding high and low-quality pasture silage is demonstrated in a DairyNZ trial comparing the milk performance of cows fed high (10.4 MJME/kgDM), medium (9.4 MJME/kgDM) and low (8.3 MJME/kgDM) quality pasture silage in the spring, summer and autumn.

On average, the cows that were fed high-quality pasture silage produced 0.22kgMS/cow/day more than the cows fed low-quality pasture silage.

At a $7/kgMS payout, this equates to an increased return of over $1.50 per cow, per day for high-quality pasture silage.

So, how do you ensure your pasture silage is high-quality? It requires a combination of quality pasture, excellent fermentation and excellent stack or bale and feed-out management.

For high-quality pasture silage, ensure you harvest pasture silage no later than 35-40 days after the last grazing, or when a maximum of 10% of the ryegrass seed heads have emerged. Failure to do so can see the feed value of the ryegrass plant drop rapidly as it enters the reproductive phase – as much as 0.3 MJME/kgDM per week of closure. Low quality grass will always result in even poorer quality grass silage

Once it is cut, ensure the pasture is wilted to at least 28% drymatter as quickly as possible. Wilting concentrates the plant sugars and reduces the risk of nutrients being lost from the silage stack as leachate, one of the most environmentally damaging wastes on a farm.

Adding a quality silage inoculant at harvest-time can also help reduce fermentation losses and improve silage quality. Quality silage inoculants contain the right strains of lactic acid-producing bacteria to ensure a good fermentation.

Trials show that when fed to dairy cows, Pioneer brand 1127-inoculated pasture silage produced 30L more milk per tonne than the untreated silage, generating a return of more than $4.75 per dollar invested.

Finally, ensuring pasture silage is compacted and sealed properly is paramount. For stacked silage, spread the material into 100-150mm layers and compact until the surface is firm. Use a high-quality plastic cover and weigh it down with tyres that are touching and seal the edges with sand or lime.

For baled silage, use high-quality wrap and apply it according to the manufacturer’s recommendations (i.e. use the recommended stretch factor and number of wraps).

Doing everything right makes good economic sense. It costs as much to make low-quality pasture silage as it does to make high-quality silage, but the returns are vastly different. Don’t waste great grass by making crap silage.

Focusing on the silage-making process this spring will help improve returns and ensure your herd is getting the best nutrition possible this season.