Effects of Lactobacillus buchneri NCIMB 40788 and forage: Concentrate ratio on the growth performance of finishing feedlot lambs fed maize silage

Inoculation of maize silage with Lactobacillus buchneri has improved livestock production in some cases, but the published literature has shown that results depend on the dietary forage: concentrate (F:C) ratio; however, there is little knowledge on the interaction between the silage inoculant and F:C ratio. Thus, we aimed to investigate the effect of feeding maize silage inoculated with L. buchneri NCIMB 40788 and two F:C ratios on feed intake and growth performance of lambs. Twenty-eight Dorper x Santa Ines lambs were arranged in a randomized block design (n = 7) and then assigned to one of four diets as follows: 1) untreated maize silage (with no silage inoculant) and low concentrate (400 g/kg dry matter (DM); US-LC); 2) maize silage inoculated with L. buchneri and low concentrate (400 g/kg DM; IS-LC); 3) untreated maize silage and moderately high concentrate (600 g/kg DM; US-HC); and 4) maize silage inoculated with L. buchneri and moderately high concentrate (600 g/kg DM; IS-HC). There was an interaction between inoculation and F:C ratio for DM intake (DMI), in which lambs fed the US-LC diet had lower DMI (P = 0.013) than that of all the other diets. Inoculation decreased crude protein (CP) digestibility (P = 0.003; -6.1%). As compared with the LC diet, the HC diet had a lower (P <= 0.016) apparent digestibility of DM, organic matter, and CP. Inoculation increased the average daily gain of lambs (P = 0.022) mostly when they were fed the LC diet than that observed for the HC diet. In conclusion, inoculation of maize silage with L. buchneri improved lamb production on feeding of diets having a higher proportion of silage, but this response was not accompanied of higher profitability. Additionally, the response of L. buchneri on lamb production is highly dependent of the F:C ratio. (AU)