Comparison of glucose and lactate concentrations between healthy equine and mule foals, and of an automated laboratory analyzer and Accutrend ® Plus system

Mules are hybrids resulting from breeding between female horses (Equus caballus) and male donkeys (Equus asinus). Information about physiological adaptation of newborn mules is scarce in literature. Profiles of blood glucose (GLUC) and lactate (LACT) concentrations are important to evaluate neonates, as they indicate metabolic dysregulations, disease severity, and prognosis. Thus, fast and affordable GLUC and LACT evaluations at farms using portable analyzers would be valuable. Additionally, it is important to know the pattern of variation of these parameters to differentiate healthy and compromised equid neonates. We hypothesized that portable devices measure glucose and lactate concentrations accurately, that these parameters differ between equine and mule foals, and vary over time. Aims of this study were to: 1) compare GLUC and LACT blood concentrations between equine and mule foals during their first 720 hours of life; 2) evaluate LACT and GLUC profiles from birth to 720 hours of life; and c) establish the correlation of LACT and GLUC concentrations using Accutrend ® Plus system (ACP) with whole blood and Randox Daytona automated analyzer (AUTO) with plasma in both species. Healthy equine (n = 16) and mule foals (n = 15) were used and blood samples were collected immediately (T0), 1 (T1), 6 (T6), 12 (T12), 24 (T24), 168 (T168), and 720 (T720) hours after birth. GLUC and LACT concentrations were evaluated with an AUTO and with an ACP. Data were analyzed by repeated measures using PROC MIXED and intraclass coefficient correlation (ICC) between 2 analyzers was calculated. Overall, GLUC concentrations evaluated with AUTO were different between species; LACT concentrations were higher (p < 0.05) in equine foals when compared to mule foals (2.14; 1.01 - 5.99 and 1.83; 0.61 - 9.04 mmol/l, respectively). There was no difference in GLUC and LACT results evaluated with ACP for equine and mule foals. Pattern of variation of GLUC evaluated with both analyzers for equine and mule foals changed during first 720 hours of life, with an increase in GLUC concentrations soon after nursing and then a decrease to baseline levels. LACT pattern of variation was similar for all foals, with both analyzers detecting higher LACT values at T0 (4.05; 1.91 - 9.04 mmol/l), with a progressive decrease until T720 (1.21; 0.61 - 5.88 mmol/l). The ICC for equine and mule foals between AUTO and ACP for GLUC concentrations was low and was moderate for LACT concentrations (ICC < 0.90). We concluded that GLUC and LACT concentrations changed during first 720 hours after birth in mule and equine foals, with GLUC values differing between species. Additionally, we recommend standardization of the ACP with specific samples before clinical use for GLUC and LACT analysis.

Keywords: Neonate, hybrid, equine, hematological parameters, critical ill, prognosis

Acknowledgement Supported by Coordination for the Improvement of Higher Education Personnel—Brazil (CAPES)—funding number 001 and the São Paulo Research Foundation (FAPESP—Project 2017/05425-0)

This manuscript was originally published in the journal Clinical Theriogenology Vol 12(3) Sept 2020.  Clinical Theriogenology is the official journal of the Society for Theriogenology (SFT) and the American College of Theriogenologists (ACT).  This content has been reproduced on the IVIS website with the explicit permission of the SFT/ACT.