Effects of homofermentative and heterofermentative bacterial silage inoculants on potato hash silage fermentation and digestibility in rams

Potato hash, a by-product from the food processing industry, was mixed with wheat bran (70:30) as fed basis and ensiled in 210 l drum for 3 months. Three types of potato hash silages were prepared which were: the control (no additives), bonsilage forte (BF, a homofermentative additive) and Lalsil Fresh LB (LFLB, a heterofermentative additive). After 3 months, the silos were opened and sampled for fermentation characteristics. Diets were produced by mixing potato hash silage with soybean meal (90:10) as fed basis and a digestibility study was conducted using five South African Mutton Merino rams (37.2 ± 2.21 kg live weight) per diet. Inoculating potato hash silage with BF and LFLB reduced (P<0.05) pH, WSC, butyric acid and ammonia N while increasing the concentration of lactic acid compared to the control. A higher concentration of acetic acid was obtained with LFLB inoculation compared to the other silages. The aerobic stability of the silage was improved (P<0.05) with LFLB while it was reduced with BF inoculation as indicated by higher CO2 production from the latter. Intakes of dry (DM) and organic matter (OM) were not affected while that of gross energy and CP were improved (P<0.05) with BF and LFLB inoculations. Inoculants increased CP, energy and aNDF digestibility, but did not alter DM or OM digestibility. Inoculating silage with BF improved (P<0.05) digestibility of ether extract compared to the other treatments, and inoculations resulted in higher (P<0.05) N intake and retention. It is concluded that BF and LFLB improved silage fermentation and diet digestibility of CP, aNDF and gross energy. Inoculation with LFLB improved aerobic stability whilst BF inoculation reduced it.