September 21, 2007

Toasted feed for milk yield still variable

Toasting feed ingredients to increase the supply of metabolised protein under organic feeding conditions is erratic between feeds.

The effects of toasting blue lupins, soy or barley used as supplement for high-yielding, organic dairy cows fed grass-clover silage was first conducted by Danish researchers was carried out at an organic farm during 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 soy. Each time the same forage mixture of grass-clover silage (84 of dry matter or DM), grass pellets (11 percent of DM) and straw (5 percent of DM) was fed unlimited.

The study revealed the following 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 soy did not affect milk yield.
  
• Toasted lupins decreased milk protein, and toasting of soy did not have an effect on milk protein.
  
• Energy correct milk (ECM) yield was significantly higher for cows fed toasted soy than for cows fed untreated soy.

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

From these results, the researchers conclude that the potential of toasting to increase the supply of metabolised protein under organic feeding conditions is variable between feeds.