|Contreras-Govea, Francisco - UW-MADISON AGRONOMY DEPT.|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: March 21, 2008
Publication Date: July 7, 2008
Citation: Contreras-Govea, F.E., Muck, R.E., Russell, J.B. 2008. Streptococcus bovis as a Silage Inoculant, a Second Chance. Journal of Dairy Science. 91(E-Supplement 1):31. Technical Abstract: Previous research indicated that Streptococcus bovis, a lactate producing ruminal bacterium, was similar or better than commercial silage inoculants. This study assessed the potential of two S. bovis strains, JB1 (a bacteriocin negative strain) and HC5 (a bacteriocin producing strain). Four treatments were used, uninoculated (Control), a commercial inoculant containing Lactobacillus plantarum (Ecosyl strain MTD/1), JB1 and HC5 using third cut alfalfa (50% DM, AS1) in 2005 and third cut alfalfa (38% DM, AS2) in 2006. All inoculants were applied at 10^5 CFU/g forage. Ten 0.5-L mini-silos were used for each treatment. Silages were allowed to ferment at 39°C for 1, 2, 4, and 60 days and analyzed for pH, ammonia-N, non-protein nitrogen (NPN), organic acids, and ethanol. Two mini-silos per treatment were opened after 1, 2, and 4 d, and four mini-silos on d 60. After 60 d with AS1, MTD/1 was the only treatment having pH < 5.0 (4.84). The pH values for Control, JB1, and HC5 ranged from 5.36 to 5.44. With AS2, pH was lower for MTD/1 (4.57) and JB1 (4.62) than Control (4.73) and HC5 (4.72) (P > 0.05). With AS1, ammonia was lower for MTD/1 (1.62 % TN) than Control (1.97% TN), JB1 (1.94% TN), and HC5 (2.21% TN) (P < 0.05). With AS2, ammonia was lower for MTD/1 (2.35% TN), JB1 (2.34% TN), and HC5 (2.46% TN), than Control (2.59% TN) (P > 0.05). With AS1, lactate was greater for MTD/1 (60.2 g/kg DM) than the other treatments (P < 0.05) whereas with AS2 lactate was similar among treatments (P > 0.05). We conclude that S. bovis JB1 was a more effective inoculant than HC5, and similar to the commercial inoculant in one of two trials. The inability of HC5 to perform as well as (or out-perform) JB1 maybe related to a 10% slower growth rate, and the susceptibility of its cell-free bacteriocin to peptidases.