Guessing silage dry matter is risky business

Estimating silage dry matter is a lot harder than many farmers and forage consultants think, according to results from a challenge laid down by Sciantec Analytical Services at this year’s Dairy Event and Livestock Show.

The company, which specialises in forage and other analytical services, asked visitors to use their skills and experience to estimate the DM content of six different silage samples that had previously been tested in the lab.

And the results highlighted how difficult assessing DM can be, says Linda Forbes, business development manager for Sciantec.

“Many of those who participated have years of experience and even they found it difficult – especially when it came to estimating the higher DM silages.”

The average estimates for the two highest DM silages were just 49 and 37.5 respectively, compared to the actual DM values of 61.3 and 55.2.

“In both case, the contribution from the silage was effectively undervalued. If this happened in the field it would likely lead to inflated feed bills.”

At the lower end of DM silages, the average estimates were much closer to the actual figures. “However, the averaging process hides a wide variation in individual estimates,” Ms Forbes says.

“Whilst the test was only intended as a bit of fun, it has clearly demonstrated in-field assessments are fraught with difficulties.

“And the most reliable way of valuing the nutritional contribution from silage is to test the samples,” she concludes.