Farm Table says:
What is the problem?
Brassica (Brassica napus) and Lucerne (Medicago sativa) are common forage crops for finishing lambs, particularly in summer dry environments. Anecdotal evidence suggests these finishing feeds have been associated with negative effects on lamb flavor without robust supportive evidence. An experiment was designed to objectively measure and characterize the differences in the flavor of lamb meat finished on different forage types
What did the research involve?
A trial in south-west Victoria was undertaken during the particularly dry 2012-13 summer on finishing crops including Lucerne, perennial ryegrass (Lolium perenne) and two varieties of forage Brassica. 125 lambs were randomised to eliminate breed and sire effect and subsets of 25 animals grazed each treatment over a 6-week period.
What were the key findings?
Significant forage quality differences were detected between both the Brassica treatments and within individual plant segments of those treatments. The three stem components of ‘Titan’ (higher, middle and lower) were significantly greater for Metabolisable Energy and significantly lower (P<0.05) in Neutral Detergent Fibre and Acid Detergent Fibre than ‘Greenland’, with the exception of the lower leaf components for ADF.
Whilst the lamb growth performance data was un-replicated, it indicated that lamb growth rate potential on the two forage Brassica treatments were greater than both the Lucerne and the grain supplemented perennial ryegrass. From this study, forage Brassica proved a useful crop for finishing lambs in a dry summer environment providing high-quality feed and utilization differences between cultivars.