Effect of single and mixed strain probiotics on feed intake, digestibility, milk yield, composition and methane emission of milking dairy cows

Abstract

Probiotics are widely used in diets of ruminants to modulate rumen metabolism which ultimately enhance nutrient utilization and animal performance. Methane gas emission by ruminants results in 4-12% loss in gross energy of the feed energy ingested by the animal. Mixed strain/species probiotics may enhance the capability of colonizing the gastro-intestinal tract, combining the different mechanisms of each strain/species in a synergistic way. Experiments were conducted to determine the effect of single and mixed strain probiotics on feed intake, digestibility, milk yield and methane emission of dairy cows. Feed intake was measured by weighing feed offered and feed refusal. In-vitro gas production was measured at 0, 3, 6, 12, 24, 36, 48, 72 and 96 hr to detennine the potential digestibility of the feed. Gas produced during in-vilro gas production was siphoned from each sample and taken for rumen methane analysis using a GC-flame ionization detection (FID) gas chromatography. To determine milk yield and composition; fifteen lactating Friesian dairy cows were fed with five experimental diets: Tl (Basal diet - control), T2 (40g Lactobacillus plantarum + basal diet), T3 (40g Saccharomyces cerevisiae +basal diet, T4 (ZOg Saccharomyces cerevisiae + 20g Lactobacillus planlarum + basal diet) and T5 (40g Saccharomyces cerevisiae + 40g Lactobacillus plantarum + basal diet) each having three replicates in a multiple linear model. Initial weight, parity, stage of lactation, breed and age of each cow was fitted as covariates during data analysis. Data was subjected to analysis of variance using General Linear Model of SAS and mean separation done using Tukey’s (HSD) test at P<0.05 significant level. Results of feed intake showed that probiotic supplementation had significant effect (P<0.05) on feed intake with the highest feed intake observed in T5 (ll.0ll:l:O.66KgDM/day) and the lowest feed intake in T1 (9.533:l:0.66KgDM/day). Calculated OMD% was significant (P<0.05) and ranged from 59.560i2.499 to 38.773i2.499 MJ/KgDM. ME differed significantly (P<0.05) with the highest in T5 (8.050 :kO.425 M]/KgDM) and lowest in T2 (4.5l7i0.425 MJ/KgDM). Concentration of short chain fatty acid (SCFA) differed significantly and ranged from O.750:l:0.045 in T5 to 0.4073: 0.045 in T2. Milk yield was significantly affected with the highest milk yield at 4.6 L and the least was from T5 at 3.8 L. No significant effect on milk composition was noted between the five dietary treatments. A combination of Lactobacillus plantarum and Saccharomyces cerevisiae increased feed digestibility and decreased rumen methane emission when used in modulation in dairy cows. Lactobacillus plantarum had no significant effect on dry matter intake.