Direct-fed microbial supplementation and health and performance of pre- and postpartum dairy cattle: a field trial.

A double-blind field trial was conducted on a commercial dairy to study the effects of feeding a direct-fed microbial (DFM) product consisting of 2 strains of Enterococcus faecium plus Saccharomyces cerevisiae yeast on prepartum and postpartum performance of Holstein cows. Treatments consisted of the normal pre- and post-fresh TMR supplemented with the DFM (2 g/cow per d) or a placebo. Treatments started approximately 10 d prepartum and continued until about 23 d in milk (DIM). A total of 366 Holstein cows were enrolled in 1 of 2 placebo groups or 2 DFM-supplemented groups. Groups were enrolled consecutively, starting with the placebo treatment. Sample size was limited to 4 groups because the cooperating dairy prematurely terminated the study due to increased health problems in one of the groups. Blood samples were taken during the prefresh period between 2 and 10 d prior to calving and at weekly intervals from 3 to 23 DIM. Blood concentrations of nonesterified fatty acids before calving and beta-hydroxy-butyrate after calving were not affected by treatment. Supplementation with the DFM product increased milk fat percentage for the first lactation cows and increased milk protein percentage for the second and greater lactation cows during the first 85 DIM. Second-lactation cows fed the DFM product received fewer antibiotic treatments before 85 DIM than cows receiving the placebo. This validated the dairy producer's concern that cows consuming one of the diets (revealed to be the placebo diet after the study was completed) were experiencing more health problems. Most measures of milk yield were numerically increased by supplementation with the DFM product. However, differences in milk yield were not significant. Key covariates for main study outcomes included milk yield in the previous (first) lactation, body condition score prior to calving, days spent in the maternity pen, and stocking density of the pre-fresh pen.

Direct-fed microbial supplementation on ruminal digestion, health, and performance of pre- and postpartum dairy cattle.

Effects of supplementing direct-fed microbial agents (DFM) to dairy cows during the transition period were evaluated. Forty-four Holstein cows were fed close-up and lactating diets that did or did not contain 2 g of DFM/cow per d. The direct-fed microbial (DFM) supplement was fed at a rate of 2 × 109 viable yeast cells and 5 × 109 cfu of bacteria per cow per day [corrected].Supplemented cows were fed the DFM 21 d prior to expected calving date through 10 wk postpartum. Cows supplemented with DFM had higher estimated ruminally available dry matter (DM) for both corn silage and haylage than did control cows. Supplemented cows consumed more DM during both the pre- and postpartum periods. In addition, those supplemented with DFM produced 2.3 kg more milk/cow per d than did nonsupplemented cows. There was no difference in 3.5% fat-corrected milk. Milk fat percentage was lower, but not depressed (4.76 vs. 4.44%) for cows receiving DFM. There were no differences in milk fat yield or milk protein percentage and yield. Cows consuming DFM had higher blood glucose postpartum, as well as lower beta-hydroxybutyrate levels both prepartum and on d 1 postpartum. Plasma nonesterified fatty acid concentration was not statistically affected by DFM, but was numerically lower prepartum and higher postpartum for supplemented cows. This study demonstrated that targeted DFM supplementation enhanced ruminal digestion of forage DM. Early lactation cows receiving supplemental DFM produced more milk and consumed more DM during the pre- and postpartum periods. Cows consuming DFM, however, experienced a lower, but not depressed, fat percentage compared with nonsupplemented cows.

Direct-fed microbial supplementation on the performance of dairy cattle during the transition period.

The influence of a direct-fed microbial (DFM) on the prepartum period and the effects on production performance during the postpartum period was investigated using 64 multiparous Holstein cows. Two close-up dry cow diets were fed to two groups of 32 cows each starting 21 d precalving as follows: 1) no DFM and 2) DFM. Post-calving cows were fed a lactation ration with or without DFM supplementation.The direct-fed microbial (DFM) supplement contained 2 × 109 viable yeast cells and 5 × 109 cfu of bacteria (Enterococcus faecium) per cow per day, top dressed in a 90-g supplement [corrected].The DMI during the prepartum period was not affected by DFM supplementation. During the postpartum period, DMI, milk yield, and milk protein content were higher for cows receiving DFM supplementation compared with no DFM. Blood glucose and insulin levels were higher and NEFA levels were lower for cows receiving DFM during the postpartum period. These data suggest that targeted DFM supplementation increased DMI and milk production postpartum. Blood metabolite information would suggest this response was associated with more glucose being made available and less fatty acids being mobilized from lipid stores.

Evaluation of an indwelling ruminal probe methodology and effect of grain level on diurnal pH variation in dairy cattle.

To evaluate a ruminal probe for recording diurnal variation in rumen pH, we fitted three ruminally fistulated cows with probes affixed to the inside of the cannula. Probes were connected to a data logger and readings were recorded hourly. The experiment was a Latin square design with cows fed three different diets: 50, 60, and 70% grain as a total mixed rations once daily. Feed offerings and refusals were recorded daily. The experimental period was 21 d. The first 6 d were for adaptation, followed by 5-d rotations through each of the diets. Daily probe readings were recorded at 4-, 6-, 8-, 12-, and 24-h intervals. At each interval, readings were recorded (precleaned), a sample of rumen fluid was taken, and pH was measured in the laboratory. As probes were removed from the rumen, probe ends were cleaned with 0.1 N HCl and reinserted into the rumen, and a reading was recorded (postcleaned). No protective pH probe shields were used in this experiment. There were no differences between pre- and postcleaned pH readings across cows for all diets. Mean time under pH 5.0, 5.5, and 6.0 were 0.2, 2, and 7.2 h, respectively. Diet affected length of time under a certain pH, only for readings under pH 6. Diurnal pH profiles were monophasic in nature. The degree of acidity increased after feeding and duration of nadir increased with increasing grain in the diet. Daily DMI increased but was highly variable within the first week after switching to the next higher grain level. These results indicate the use of an indwelling ruminal probe without a protective shield, cleaned, and calibrated daily can accurately measure diurnal variation of ruminal pH. In addition, transition to higher grain levels in the diet increases pH, duration of pH nadir, and daily DMI fluctuation.

Ruminal supplementation of direct-fed microbials on diurnal pH variation and in situ digestion in dairy cattle.

To evaluate the effect of direct-fed microbial (DFM) concentration on diurnal rumen pH profiles and in situ digestibilities, nine ruminally cannulated cows in early lactation were fed treatments consisting of DFM (Enterococcus faecium, Lactobacillus plantarum, and Saccharomyces cerevisiae) at a level of a) 1 x 10(5) cfu/ml of rumen fluid (10(5)), b) 1 x 10(6) cfu/ml of rumen fluid (10(6)), and c) 1 x 10(7) cfu/ml rumen fluid (10(7)). Treatments were directly administered via rumen cannula once daily. Cows were fitted with pH probes in their cannula and connected to dataloggers, which monitor pH hourly. The experimental period was 21 d: 7-d adjustment, 14-d for pH, and in situ measurements. Cows fed 10(5) were able to sustain a higher nadir pH than were cows fed 10(6) or 10(7). Cows fed 10(5) had a higher digestion rate of high moisture ear corn (HMEC) dry matter. Corn silage digestion was higher for cows fed 10(5) and 10(6) compared with those receiving 10(7). There were no carryover effects of treatment associated with rumen pH when switching from one treatment regimen to the next. Results from this study demonstrate that incorporation of a specific level of DFM aids in reducing diurnal ruminal acidity.