Replacement of alfalfa with Tithonia diversifolia in lambs fed sugar cane silage-based diets and rice polishing

Abstract

The aim was to evaluate the effect of replacing alfalfa (AA) with Tithonia diversifolia (TD) in sugar cane silage (SCS) based lamb diets, both with or without supplementation with rice polishings (RP), on in vitro digestibility, nitrogen retention and productive performance. The experimental diets (D) contained the following: D1) 68.6 % of SCS and 29.4 % of TD; D2) 63.7 % of SCS and 34.3 % of AA; D3) 46 % of SCS, 22.6 % of TD and 29.4 % of RP; and, D4) 44.1 % of SCS, 24.5 % of AA and 29.4 % of RP. Diets were isoproteinic and isocaloric. The in vitro digestibility of dry matter and organic matter were greater (P<0.05) with D2 compared to D1 and increased (P<0.05) with RP supplementation, with no difference between D3 and D4. Similarly, productive performance was not different (P>0.05) between diets containing TD or AA. Nevertheless, RP improved (P<0.01) dry matter intake, average daily gain and total body gain with both forages. In conclusion, in sugar cane silage based diets, the replacement of alfalfa with Tithonia diversifolia has no effect on DM digestibility, N retention or productive performance. Complementation with rice polishings improves DM digestibility, N retention and productive performance in animals fed forage rich diets such as those utilized in this study.