11 August 1995

Ammonia appetiser

AMMONIA-treated straw increases the rate at which store lambs adapt to eating straw when housed, according to a trial carried out at Reading University.

Earlier work showed newly housed previously pastured lambs were reluctant to eat straw. So the Reading trial monitored intake and diet-induced behaviour in newly-housed lambs to determine the effect of ammonia treatment on rate of adaption to straw diets.

Sixteen 35kg seven-month-old Suffolk x Mule lambs were housed in October in continuously lit pens, and fed untreated or ammonia-treated winter wheat straw.

Lambs were also offered 240g DM/day of a barley-based supplement over the 21-day trial. The behaviour study involved recording eating, drinking, idling and ruminating every five minutes for nine hours on day one and 12 hours on day eight and 16.

Results showed lambs adapted more readily to ammonia-treated straw and intakes consistently exceeded those for untreated straw. During days three to 11 ammonia-treated straw intake averaged 828g DM/day a day, compared with 299g DM/day for untreated straw.

Although the average eating time was similar for both diets, lambs offered ammonia-treated straw frequently withdrew from the feed trough for about three minutes and then continued eating.

That could indicate irritation to the eyes by the ammonia.