Humberto B. Magalhaes, Ilaria Colombo, Kianna M. Spencer, Giorgia Podico, Igor F. Canisso
Article Summary
Accurate prediction of parturition is paramount to ensuring monitoring of delivery and preventing complications. Assessing the pH and electrolytes of the mammary gland secretions helps detect impending parturition. As conductivity is related to electrolyte concentrations and pH, it could be a useful alternative for predicting impending parturition; however, this hypothesis warrants a critical assessment. The aim of this field study was to assess the ability of conductivity, pH, and Brix in the mammary gland secretions to predict parturition and to investigate their associations.
The mammary gland secretions of periparturient mares (n = 241) were assessed daily for conductivity, pH, and Brix index from 320 days until parturition using stable-side handheld devices (Compact Conductivity Meter EC22, Horiba Scientific, Laqua-twin; Compact pH Meter PH22, Horiba Scientific, Laqua-twin; and a Brix refractometer, respectively). Receiving operating curve cut-off values for conductivity (≤4.8 mS/cm), pH (≤6.4), and Brix index (>23.6%) were used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for predicting parturition in ≤24 h.
Impending parturition was associated with a significant reduction in conductivity and pH (p < 0.05), and conductivity was strongly correlated with pH (r = 0.88) and Brix (r = −0.80) (p < 0.05). Sensitivity, specificity, PPV, and NPV for parturition in ≤24 h for conductivity (82%, 91%, 77%, and 92%, respectively), pH (79%, 84%, 81%, and 71%, respectively), and Brix (72%, 79%, 66%, and 83%, respectively) were determined separated and pairwise. Of interest, the sensitivity, specificity, PPV, and NPV, of combining conductivity and pH, were 80%, 95%, 90%, and 88%, respectively. Conductivity (≤4.8 mS/cm) presented the greatest odds ratio for predicting parturition in ≤24 h and coupling it with pH (≤6.4 pH units) doubled its odds ratio (i.e., 25.4–62.3).
Bottom line: The conductivity of mammary gland secretions and a combination of conductivity and pH are useful for predicting parturition in mares.
Why I chose this article
This paper discusses a non-invasive technique using a stable-side handheld device to determine the value of monitoring milk electrolytes for impending parturition.
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