21 November 1997

Maize silage may not be all it seems…

EARLY reports of high quality maize silage in clamps this year may be misleading in the light of further analyses, which suggest quality is similar to previous years.

ADAS reports high average dry matter, variable starch and low proteins. Proteins are also lower than last year according to Axient, although other results are similar.

Axient has analysed 100 samples averaging 30% DM, 11.1 ME, 8.6 % CP and 28% starch. ADASs 700 samples average 34% DM, 11 ME, 8.8% crude protein, 42 NDF, 27% starch and 4.6pH.

ADAS nutritionist Bruce Cotrill warns that the protein levels this year, at 8.8 %, is 2% lower than book values and a higher protein concentrate may be needed.

And while some maize being fed is 40% starch and a powerful feed, Dr Cotrill warns some starches are low at 10%.

"There is also some evidence that a higher maize silage DM increases the proportion of by-pass starch and may increase milk protein %. But when more starch by-passes rumen fermentation, more energy may be needed by the rumen bugs."

A high DM crop may also be less stable in the clamp. And although the average crop pH is high, results are variable, and when pH is low cow intakes may be reduced, he warns.n


&#8226 Overall quality similar.

&#8226 Lower proteins.

&#8226 More by-pass starch.