Effect of a Direct-Fed Microbial on Plasma Concentrations of Hormones And Metabolites in Primiparous And Multiparous Holstein Cows

Abstract

This study was conducted to evaluate the effect of supplemental feeding Propionibacterium P169 on key metabolic indicators in lactating cows. From 14 d prepartum to 175 d postpartum, multi- and primiparous Holstein cows were fed one of three dietary treatments: 1) Control (n = 13) fed a total mixed ration (TMR); 2) High-dose group (n = 11), fed TMR plus 6 x 1011 /head /d (high-dose P169) of Propionibacterium Strain P169; or 3) Low-dose group (n = 14), fed TMR plus 6 x 1010 /head/d (low-dose P169) of P169. Blood samples were collected weekly for 30 wk and analyzed for plasma concentrations of glucose, insulin, insulin-like growth factor-I (IGF-I), leptin, nonesterified fatty acids (NEFA), and cholesterol (CHOL). Between wk 25 and 30, bovine somatotropin (bST) was given to all groups every 2 wk. Plasma glucose concentrations were affected by diet x parity such that plasma glucose in low-dose P169 multiparous cows (59.8�1.1 mg/dL) were 5.5% lower than in high-dose P169 multiparous cows; low-dose P169 primiparous cows (67.9�0.9 mg/dL) had 6% to 9% greater plasma glucose concentrations than high-dose P169 and Control primiparous cows. Plasma insulin concentrations were affected by diet such that low-dose P169 had less plasma insulin than high-dose P169 and Control cows (during wk 13-25), and high-dose P169 cows had greater insulin than Controls (during wk 1-12). Plasma IGF-I, NEFA and leptin concentrations did not differ among diet groups between wk 1 and 25, but primiparous cows had greater IGF-I and lower NEFA levels than multiparous cows. Plasma CHOL was affected by diet x parity such that low-dose P169 multiparous cows (246�11 mg/dL) had 25% greater concentrations than high-dose P169 and Control multiparous cows; CHOL levels in primiparous cows did not differ among diet groups. During bST, high-dose P169 multiparous cows and low-dose P169 primiparous cows had lower IGF-I concentrations than their respective Controls. Regardless of parity, low-dose P169 cows had greater leptin concentrations than Controls cows, and high-dose P169 cows had greater plasma NEFA than Control cows. We conclude that P169 may hold potential as a direct-fed microbial to enhance metabolic efficiency during early and mid-lactation.