Vol.5 No.1 (2010)

SOYABEAN MEAL SUPPLEMENTATION TO MANAGE
PARASITES IN LAMBS GRAZED ON ORGANIC PASTURES
IN NORTH EAST VICTORIA

Burnett, V.F., Smith, M., Seymour, G.R. and Norng, S.

Abstract:

Over 20,000 organic lambs are produced from southern Australian farming systems each year. Internal parasite infection of organic sheep and lambs is the most common production issue mentioned by producers. In organic systems, anthelmintic drenches are prohibited under current Australian organic standards, so producers rely on cultural methods such as lower stocking rates and rotational grazing. Recent research investigated the use of supplementary protein in the management of parasites in lambs. Experiments were conducted in 2005 and 2006 to investigate the use of soyabean meal as a source of supplementary protein to reduce faecal egg count (FEC) in lamb finishing systems on either annual or perennial organic pastures. Lambs were supplementary fed with organic soyabean meal equivalent to 2.4 MJ/kg DM ME per head per day and 51g/head/day CP in 2005, and in 2006, 2.1 MJ/kg DM ME per head per day and 61 g/head/day CP; this was compared to non-supplemented lambs grazing pasture only. Soyabean meal supplementation did not reduce FEC, with the exception of only one from a total of 14 samplings in the two pasture systems over two years. This was likely due to high CP in the pasture, rotational grazing practice and limitations with the FEC methodology. Soyabean meal supplementation improved lamb growth rates in both finishing seasons on annual pasture, but final liveweight was only increased in 2006. Soyabean meal supplementation did not improve growth rate or final liveweight on perennial pasture in either season. Soyabean meal supplementation resulted in heavier (P<0.05) Hot Standard Carcase Weight in lambs grazing annual pasture in 2005. Soyabean meal supplementation of lambs grazing pasture is unlikely to be effective in seasons and under pasture conditions similar to those tested in this study.

Keywords: soyabean meal supplementation, lambs, parasites, organic

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