Submitted to: International Silage Conference
Publication Type: Abstract Only
Publication Acceptance Date: May 7, 2012
Publication Date: July 2, 2012
Citation: Muck, R.E., Broderick, G.A., Faciola, A.P., Hymes Fecht, U.C. 2012. Lactating cow response to lucerne silage inoculated with Lactobacillus plantarum. In: Kuoppala, K., Rinne, M., Vanhatalo, A., editors. XVth International Silage Conference, 2-4 July 2012, Hämeenlinna, Finland. p. 480-481. Technical Abstract: It is unclear why bacterial silage inoculants improve milk production in lactating dairy cattle. However, recent in vitro results suggest that inoculated silage effects on milk production may be tied to greater production of rumen microorganisms. Our objective was to determine if alfalfa silage treated with an effective Lactobacillus plantarum inoculant could produce a milk production response commensurate with the in vitro responses. Alfalfa [240 g crude protein (CP)/kg dry matter (DM), 300 g neutral detergent fiber (NDF)/kg DM, 500 g DM/kg] was ensiled with (LP) and without (C) Ecosyl inoculant. Twenty-eight multiparous Holstein cows in early lactation (8 ruminally-cannulated) were blocked by days in milk and randomly assigned to two diets (C or LP-treated silage) in a double crossover design with four 28-d periods. Diets were formulated to contain 165 g CP and 280 g NDF/kg DM, consisting of (g/kg DM): alfalfa silage (500), corn silage (200), high moisture corn grain (226), soy hulls (50) and vitamin/mineral mix (24). Means for LP were compared against means for C before and after LP using a paired t-test in Proc MIXED of SAS. The two alfalfa silages were of similar DM, CP, fiber and ash concentrations, but the inoculant was effective in reducing silage pH and shifting fermentation toward lactic acid. Composition was similar between the two diets. Compared to control, the LP diet increased milk production but had no effect on fat-corrected or energy-corrected milk production. There was a trend for increased DM intake with the LP diet, but efficiency of milk production was not affected by treatment. The milk protein content was reduced in the LP diet, and lactose content was increased. Daily yield of milk fat, protein and lactose was unaffected by treatment. Milk urea nitrogen was reduced by LP, suggesting that more of the degraded protein on the LP diet was being converted to microbial protein and less to ammonia in the rumen. Analysis of the omasal samples is not complete. These samples may provide more direct evidence as to whether the diet with the inoculated alfalfa silage produced more rumen microbial protein.