DIGESTIBILITY AND FEEDLOT STUDIES ON RAPESEED SCREENINGS FOR FEEDER LAMBS

Abstract

Screenings from combine-harvested rapeseed were ground and incorporated as 50 per cent of a pelleted feed containing 36.5 per cent ground oat hulls, 4 per cent dehydrated alfalfa meal, 7 per cent cane molasses, 0.5 per cent urea, 1.0 per cent dicalcium phosphate and 0.5 per cent salt. These pellets composed 0, 33, 67 and 100 per cent of the total concentrate allowance fed with hay to four lots of 20 feeder lambs during a 67-day test. The hay allowance was limited to 1.5 pound/head/day. Grain and pellets were full-fed twice daily. In a parallel digestibility study pellets were substituted for concentrate (mixed wheat, oats and barley) at the following levels: 0, 16.7, 33.3, 50 and 100 per cent and with the hay allowance held constant at 50 per cent of the ration.The pelleted mixture was found to contain 51 per cent T.D.N, and 10.6 per cent D.C.P. (dry matter basis) and when included as one-third of the concentrate fed, the lambs gained 0.47 pound/day. Increasing levels of screenings pellets beyond one-third of the concentrate portion of the ration resulted in decreasing gains proportional to the decline in percentage T.D.N. in the entire ration. Tests for isothiocyanate and thiooxazolidone revealed only traces of these toxic factors.Rapeseed screenings contain 8 to 11 per cent crude protein, about 57 per cent T.D.N. (10 per cent moisture basis), and appear to be satisfactory as an ingredient in ruminant rations.