April 08, 2019

Interpretive Summary: TMR inoculated with Lactobacillus bacteria

Interpretive Summary: Chemical composition, fermentative losses, and microbial counts of total mixed ration silages inoculated with different Lactobacillus species.

By: Anne Wallace

The addition of lactic acid bacteria (LAB) to silage can lower pH and minimize spoilage by inhibiting the growth of spoilage microorganisms. In this paper published in the April 2019 Journal of Animal Science, total mixed ration (TMR) forage silage was inoculated with two strains of Lactobacillus bacteria. The authors hypothesized that the addition of these LAB would improve the fermentation profiles and aerobic stability of TMR.

Total mixed ration (comprised of corn, ryegrass and soybean ingredients) was formulated to meet the needs of milk-producing dairy cows. Prior to ensiling, the TMR was either uninoculated (control, CON), or inoculated with Lactobacillus buchneri CNCM I-4323 (LB) or Lactobacillus plantarum N2072 (LP) at a concentration of 105 colony-forming units per gram. Ensiling took place for 15 and 60 days in silos (randomized 3x2 factorial, 5 replicates per treatment). 

At 15 days, LP and LB had a significantly lower concentration of Neutral Detergent Fiber (NDF)and butyric acid, compared to CON. Also, loss of DM was greater and aerobic stability was lower in LP. At 60 days, there was increased lactic and acetic acid, ammonia nitrogen and aerobic stability—consistent across all treatments (CON, LP, LB)—when compared to TMR analysis at 15 days. At 60 days, the pH and aerobic stability of LP was lowest, when compared to LB and CON. Bacterial activity in LP and LB was found to be sufficient at 60 days. 

Overall, the aerobic stability and fermentation process was not improved by the addition of LP and LB in this study. It is possible that the concentration of LAB inoculant, strains used, type of feed, experimental conditions, or other factors may have affected these results. The authors do note however that the study supports a 60-day ensiling period. More studies to better understand how LAB can effectively minimize spoilage of silage is justified. 

To view the article, visit the Journal of Animal Science.