• Open Access

D-Lactate Production and Excretion in Diarrheic Calves

Authors

  • Julia B. Ewaschuk,

    1. College of Pharmacy and Nutrition (Ewaschuk, Palmer, Whiting, Zello), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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  • Jonathan M. Naylor,

    1. Western College of Veterinary Medicine (Naylor), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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  • Randi Palmer,

    1. College of Pharmacy and Nutrition (Ewaschuk, Palmer, Whiting, Zello), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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  • Susan J. Whiting,

    1. College of Pharmacy and Nutrition (Ewaschuk, Palmer, Whiting, Zello), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
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  • Gordon A. Zello

    Corresponding author
    1. College of Pharmacy and Nutrition (Ewaschuk, Palmer, Whiting, Zello), University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
      College of Pharmacy and Nutrition, 110 Science Place, Saskatoon, SK, Canada S7N 5C9; e-mail: Gordon.Zello@usaskca.
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College of Pharmacy and Nutrition, 110 Science Place, Saskatoon, SK, Canada S7N 5C9; e-mail: Gordon.Zello@usaskca.

Abstract

The origin of D-lactate, the most important acid contributing to metabolic acidosis in the diarrheic calf, is unknown. We hypothesized that because D-lactate is produced only by microbes, gastrointestinal fermentation is the source. The objective of this study was to determine whether D-lactate production occurs in the rumen, colon, or both, and to measure D- and L-lactate concentrations in urine. Fecal, rumen, blood, and urine samples were obtained from 16 diarrheic and 11 healthy calves. Serum electrolyte concentrations were measured in both groups, and blood gas analyses were performed for diarrheic calves. All samples were analyzed for D- and L-lactate by high performance liquid chromatography (HPLC). Diarrheic calves were generally hyperkalemic with high serum anion gap, depressed serum bicarbonate, and low blood pH. L-lactate was markedly higher in rumen contents (22.7 mmol/ L [median]) and feces (8.6 mmol/L) of diarrheic calves than healthy calves (0.5 mmol/L and 5.1 mmol/L, respectively), but not different in serum or urine. Rumen, fecal, serum, and urine D-lactate concentrations were all significantly higher (P < .05) in diarrheic calves (17.0, 25.4, 13.9, and 19.2 mmol/L, respectively) than in healthy calves (0.5, 9.1, 1.4, and 0.5 mmol/L, respectively). Higher D-lactate concentrations in the rumen and feces of diarrheic calves suggests these sites as the source of D-lactate in blood and urine.

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