The impact of direct-fed microbials and enzymes on the health and performance of Holstein cattle with emphasis on colostrum quality and serum immunoglobulins in the cal

Research has shown that direct-fed microbials (DFM) and enzyme supplementation can impact the dry matter intake (DMI), milk production, and milk composition. However, limited research has evaluated the impact of DFM and enzyme supplementation on colostrum quality and the uptake of the Immunoglobulins A and G (IgA and IgG) by calves. In this study, 36 multiparous Holstein cows were blocked by expected calving date and randomly assigned to 1 of 3 treatments 3 weeks prior to calving and remained on these treatments until week 8 postpartum. These treatments were: 1) 0 g of DFM and enzyme (control), 2) 45.40 g/d of Tri-LutionRTM (Tri), or 3) 45.40 g/d of Tri-LutionRTM and 18.16 g/d of Zy-mendRTM (Tri + Zy). The amount of total mixed ration (TMR) fed and orts refused were measured each day to determine DMI. Blood samples were taken on the cows every Monday, Wednesday, and Friday at 1100 h from the coccygeal veins and arteries to be analyzed for beta-hydroxybutyrate (BHBA), glucose, and nonesterified fatty acids (NEFA). Cows were also weighed once a week throughout the course of the study. Colostrum was harvested and weighed at parturition and later analyzed for IgA and IgG concentration via radial immunoassay. Calves were fed 4 L of maternal colostrum within 2 h after calving. Blood samples were also taken from the calves at 0 and 24 h in order to be analyzed for IgA and IgGconcentrations and to determine apparent efficiency of absorption of IgA and IgG. Finally, milk yields were taken daily for 8 wk postpartum and samples were taken once a week and sent to DairyOne (Ithaca, NY) to be analyzed for quality. Prepartum body weight (BW), BW, efficiency of gain, DMI, BHBA, NEFA, and glucose concentrations were not impacted by treatment. There was also no impact of treatment on colostrum yield, IgA and IgG content, and composition with the exception of IgA yield and ash percentage. The ash percentage of colostrum tended (P = 0.07) to increase with the Tri and Tri + Zy treatments while the IgA yield (P = 0.05) decreased with the Tri treatment. Treatments did not impact BW, serum IgA and IgG concentrations or apparent efficiency of absorption of IgA and IgG of the calves. Postpartum BW, DMI, blood metabolites, milk production and composition, with the exception of BW gain and somatic cell score (SCS), of the cows were not impacted by treatment. Cows on the Tri treatment gained more BW (P =0.03) and tended to have a greater efficiency of gain (P = 0.09) in comparison to those on the Tri + Zy treatment, but both treatments did not differ from the control. This suggests that there is a negative effect of applying the Tri-LutionRTM and Zy-mendRTM together which might be due to negative interactions among ingredients and microorganisms. An increase in SCS (P = 0.04) was also observed with the Tri treatment. All these results indicate that the supplementation of DFM and enzymes is not beneficial in improving the health and performance of dairy cattle during the transition period and early lactation.