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Measurement of urine pH and Net Acid Excretion and their association with urine calcium excretion in periparturient dairy cows

J Dairy Sci • 2019
العودة
معلومات البحث
المؤلفون Constable PD, AA Megahed, MH Hiew
الكلمات المفتاحية Not Available
المجلة العلمية J Dairy Sci
الناشر Not Available
المجلد 102
العدد Not Available
الصفحات 11370–11383
publication.type International
رابط البحث Open Link
المواد المرفقة Not Available
الملخص
Urine pH (UpH) and net acid excretion (NAE) are used to monitor the degree of systemic acidification and predict the magnitude of resultant hypercalciuria when feeding an acidogenic ration to control periparturient hypocalcemia in dairy cattle. The objectives of this study were to evaluate the diagnostic performance of urine dipstick and pH paper for measuring UpH, and to characterize the UpH–NAE relationship and the association of urine Ca concentration ([Ca]) with UpH and NAE. Urine samples (n = 1,116) were collected daily from 106 periparturient Holstein-Friesian cows fed an acidogenic ration during late gestation. Net acid excretion was measured by titration, and UpH was measured by a glass-electrode pH meter (reference method), Multistix-SG urine dipsticks (Siemens Medical Solutions Inc., Ann Arbor, MI), and Hydrion pH paper (Micro Essential Laboratory Inc., Brooklyn, NY). Diagnostic performance was evaluated using Spearman correlation coefficient (rs), Bland–Altman plots, and logistic regression. Urine pH measured by urine dipstick (rs = 0.94) and pH paper (rs = 0.96) were strongly associated with UpH. Method-comparison studies indicated that the urine dipstick measured an average of 0.28 pH units higher, and pH paper 0.10 pH units lower, than UpH. Urine [Ca] was more strongly associated with UpH (rs = −0.65) than NAE (rs = 0.52). Goals for controlling periparturient hypocalcemia under the study conditions were UpH