Pregnancy toxemia, also known as pregnancy ketosis, is a metabolic disorder that can develop as a result of relative undernourishment or excessive body condition in late-gestation ewes, typically those bearing twin or multiple fetuses.1 A suspicion of clinical pregnancy toxemia is supported by a ewe's history and signalment as well as a progression of signs such as anorexia, lethargy, weakness, and neurologic abnormalities.2 When undetected or left untreated, the condition usually results in death of the ewe and its fetuses.
Treatment of pregnancy toxemia can have disappointing results and be expensive and time-consuming, particularly when multiple sheep are affected or when detection is delayed, resulting in an increase in the severity of clinical signs. Therefore, a rapid and accurate diagnosis of ketosis could increase the possibility of a successful treatment outcome while decreasing the likelihood of illness and death of affected ewes and lambs and lessening economic costs associated with delayed treatment and sheep loss.
Sheep producers and veterinarians typically use urine ketone test strips to evaluate ketone status in late-gestation ewes. The urine ketone strips can be used to semiquantitatively measure the amount of acetoacetate in urine but not of BHB, which is the primary circulating ketone body.3 Accuracy of the urine ketone test strips in dairy cows is reportedly variable, and results can be affected by environmental conditions (eg, ambient humidity or temperature), user characteristics (eg, nature of handling and interval from testing to reading), some medications, and pigmenturia.4,5 Urine collection can be difficult and is stressful for ewes because urination is most reliably induced by restraining the ewe and holding off the nares to prevent breathing.6 The ewe eventually becomes distressed and postures to urinate.
A POC meter designed to measure blood glucose and BHB concentration in humans has been evaluated for detection of ketosis in dairy cattle and dairy sheep.7–9 The only other method for measuring blood BHB concentrations in prepartum animals is with an LBA. A POC glucometer is available for veterinary use; however, it has not been evaluated or marketed for use in sheep.
Although blood glucose concentrations vary in sheep with pregnancy toxemia, they can be used to assist in evaluating response to treatment. Therefore, a reliable POC meter capable of measuring both BHB and glucose concentrations would be beneficial and economical for sheep producers and veterinarians. The objective of the study reported here was to compare blood BHB and glucose concentrations measured with a dual-purpose POC meter with those of an LBA in various environmental conditions and throughout gestation and lactation in healthy and nutritionally stressed ewes at high risk for developing pregnancy toxemia. The hypothesis was that the POC meter would yield results of sufficient accuracy to support its use for measurement of blood BHB and glucose concentrations in sheep on farms.
Coefficient of variation
Days of gestational age
Laboratory biochemical analyzer
Point of care
Precision Xtra Blood Glucose & Ketone Monitoring System, Abbott Diabetes Care, Abbott Park, Ill.
Grabber Hand Warmers, YSC Inc, Grand Rapids, Mich.
Serum Vacutainer glass blood collection tubes, Becton, Dickinson and Co, Franklin Lakes, NJ.
Roche Hitachi 917 Blood Chemistry Analyzer, Hitachi Ltd, Tokyo, Japan.
MedCalc, version 12.3, MedCalc Software, Mariakerke, Belgium.
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