Toasting not always beneficial to milk yield

Danish researchers investigated the effects of toasting blue lupins, soybeans
or barley used as supplement for high-yielding, organic dairy cows fed
grass-clover silage.

The experiment was carried out at an organic study
farm during the winter 2004/2005. Three types of feed, toasted or untreated –
all with same energy content – were examined in each experiment, with an
untreated cereal mixture as control.

The supplements tested were lupins,
barley and soybeans. Each time the same forage mixture of grass-clover silage
(84% of DM), grass pellets (11% of DM) and straw (5% of DM) was fed
unlimited.

Results

• Toasting decreased effective rumen protein
  degradability determined at the farm for all three supplements.

• Toasted lupins
  tended to increase milk yield compared to the raw beans.

• Toasting of soybeans did not
  affect milk yield.

• Toasted lupins decreased milk protein, and toasting of
  soybeans did not have an effect on milk protein.

• Energy correct milk (ECM) yield
  was significantly higher for cows fed toasted soybeans than for cows fed
  untreated soybeans.

• There was no significant effect on ECM yield from
  toasting lupins or barley.

From these results
the researcher concluded that the potential of toasting to increase the supply
of metabolisable protein under organic feeding conditions is variable between
feeds.

More details can be found in the research summary

.