BRIX refractometric analysis of mammary secretions is a poor predictor of impending parturition in mares

作者：Stout Tom A E^*; Koekkoek J; Hendriks Onstein W K

来源：Pferdeheilkunde, 2011, 27(3): 287-292.

• Foaling prediction
• mammary secretions
• sugar refractometry
• milk electrolytes
• reproduction

Equine dystocia can rapidly progress to life-threatening neonatal hypoxia and/or maternal trauma. Since the prognosis can often be improved by timely intervention, it is advisable to attend all foalings; tests that reliably predict imminent parturition are therefore invaluable. Sugar (BRIX) refractometry is accepted as a mare-side test for evaluating colostrum quality, and some studs use BRIX refractometry to indicate approaching parturition. This study compared the accuracy of BRIX refractometry with those of laboratory analysis of (Ca(2+)], [Na(+)] and [K(+)] and the Predict-a-foal (TM) test for indicating when a mare is or is not about to foal, using mammary secretions collected daily from day 325 of gestation from 30 Dutch Warmblood mares. The mean BRIX score rose progressively as foaling approached in multiparous mares: 5/22 (22%) foaled within 1 night, 8 (36%) within 36h and 11 (50%) within 60 h of achieving a BRIX score of 22%; however, 5 mares (22%) failed to achieve >20% BRIX pre-foaling. Primiparous mares reached a (near) peak BRIX score further in advance of foaling with little subsequent rise, rendering the test a poor predictor of foaling in maiden mares. Moreover, a Predict-a-foal score of 4 (14/17: 82%) and a [Ca(2+)] >= 7.5 mmol l(-1) (20/26: 77%) were better indicators of foaling within 60 h; while below threshold values were reliable indicators that fooling would not occur within 24 h (>95%). Not all mares followed the general rules; one multiparous mare showed negligible pre-foaling changes in milk electrolytes or BRIX, whereas one maiden mare showed repeated inversions of [Na(+)] and [K(+)] between days 10 and 1 pre-partum; in this maiden and a multiparous more with an early Na-K inversion, [Ca(2+)] first exceeded 7.5 mmol l(-1) 9-10 days before foaling.

• 出版日期2011-6