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Intravenous amino acid infusion in early postpartum dairy cows: Effects on performance, blood metabolites, and serum hormones.

T. L. Chandler

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06-24-2020

Abstract:

400
Intravenous amino acid infusion in early postpartum dairy cows: Effects on performance, blood metabolites, and serum hormones.
T. L. Chandler*1, T. A. Westhoff1, J. E. Cha1, A. L. Lock2, T. R. Overton1, S. Mann1. 1Cornell University Ithaca, NY, 2Michigan State University East Lansing, MI.

Early postpartum cows are deficient in amino acids (AA). Production responses to metabolizable protein (MP) infused abomasally, notably milk protein % or yield, have been observed. Our objective was to describe the response to an intravenous (IV) AA infusion designed to fill the estimated MP deficit in postpartum cows. Cows (n = 14, 4 � 1 DIM) were infused IV 24 h/d for 4 d in a matched-pair randomized controlled design and received IV AA (IVAA) or 0.9% NaCl (CTRL). Daily IVAA were infused at 10 mL/kg BW to supply 1 g/kg BW of essential and nonessential AA. Cows were fed TMR ad libitum and milked 2 � daily. Milk samples taken at each milking were analyzed and composited for milk components and milk fatty acid (FA) profile. Daily blood samples were collected before feeding and analyzed for glucose, nonesterified FA (NEFA), triglyceride (TG), insulin, and glucagon. Repeated measures ANOVA with baseline covariates were analyzed by PROC MIXED (SAS v. 9.4) with fixed effects of time, treatment (trt), time � trt, DIM, parity, and BW, and random effect of pair. Results are summarized in Table 1. Amino acid infusion limited DMI, but increased milk fat % and yield. Milk protein was unaffected. Amino acid infusion was associated with increased circulating glucagon, NEFA, and TG. Increased milk fat originated from an increase in both de novo and preformed FA. Given the effect of IVAA on TG and NEFA the source of preformed FA is of interest and should be investigated further.Table 1.

ItemCTRL (n=7)AA (n=7)SEMP-value
TrtTimeTime�trt
DMI, kg/d20.018.20.60.010.070.03
Milk, kg/d35.135.21.10.91<0.010.39
Fat, %4.935.850.09<0.01<0.01<0.01
Fat yield, g/d1720202950<0.01<0.01<0.01
de novo FA, g/d314352100.02<0.010.13
C16 FA, g/d574637270.10<0.010.01
Preformed FA, g/d72382510<0.01<0.010.09
Protein, %3.743.670.060.35<0.010.03
Protein yield, g/d13051266450.290.030.84
ECM, kg/d43.346.91.3<0.01<0.010.09
Glucose, mg/dL68.865.03.00.330.800.87
NEFA, �Eq/L(95% CI)512(344—762)893(549—1,451)0.070.940.46
TG, mg/dL8.210.41.00.100.690.13
Insulin, �IU/mL(95% CI)4.5(3.0—6.7)3.2(1.9—5.2)0.210.450.97
Glucagon, pg/mL14118811<0.01<0.010.06

Keywords: transition period, fatty acid, glucagon.