| Popis: |
Transition cows have a high risk for metabolic disease within the first 30 days in milk (DIM). Administration of direct-fed microbials (DFM) may reduce the adverse impacts that fresh cows experience during this transition period. Megasphaera elsdenii is a lactic acid-utilizing bacterium that has shown promise as a potential DFM during the transition period. Primi- and multiparous Holstein cows (n=162) at a commercial dairy herd were assigned to 1 of 4 treatments: 1) control (no dose) (n=44), 2) 200 mL Lactipro (M. elsdenii, 1 x 108 cfu/mL; MSBiotec, Littleton, CO) when cows entered (~ -14 DIM) the close-up pen (n=45), 3) 200 mL Lactipro at 1-3 d postpartum (n=39), and 4) 200 mL Lactipro prepartum and 200 mL at 1-3 d postpartum (n=34). Close-up cows were fed 72% forage (63:37 corn silage and wheat straw), and upon calving, cows entered the high group and were fed 40% forage (90:10 corn silage:wheat straw). The BCS was similar among treatments and no treatment by time interaction occurred. There was no difference in milk yield among treatments (39.7, 39.7, 39.5, and 39.8 + 0.97 kg/d) or peak milk yield. Treatment by parity interactions were detected (P < 0.05) for milk yield and peak milk yield in which mature cows (= 3 lactations) dosed prepartum had higher daily milk yield and peak milk than the control and pre- and postpartum dosed cows but did not differ from the postpartum dosed cows. The test-day milk fat and protein percentages were similar among treatments. Test-day milk fat was higher (P < 0.01) for the first (3.88%) versus second (3.38%) test-day but it was within expected levels, which is reflective of the low incidence of ketosis in the study. There was a treatment by parity interaction (P < 0.01) for milk protein. Milk protein percentage was higher for 2nd lactation cows dosed prepartum than control or cows dosed pre- and postpartum but did not differ from cows dosed postpartum. Control and pre- and postpartum dosed cows with = 3 lactations had higher milk protein percentages than those dosed only prepartum but were not different from cows dosed only postpartum. The SCC did not differ (P > 0.10) by treatment or DHI test-day and averaged 333 (x103) cells/ml across all treatments. Based on urine ketones, only 2.5% of the cows in the study experienced clinical ketosis, but cows with > 15 mg/dL urine ketones were 8.33, 14.3, 14.3, and 0% for treatments, respectively. Health incidences were low in this study and did not differ among the treatments. Reproductive performance also did not differ among the treatments. Based on this study, dosing with M. elsdenii prepartum may improve ruminal conditions of high-producing (higher parity) transition cows whereby milk yield is increased. Concentrations of dietary starch and NDF fed both prepartum and postpartum may affect animal response to dosing with M. elsdenii. |
