Bovine metabolic diseases are silent clinical conditions caused by a disturbance in normal cellular metabolic processes majorly due to the demand for nutrients, physiological stress and inflammation in lactating animals. Even though these are non-devastating diseases, conditions like mastitis and ketosis highly influence cow's lactation and fertility performance that leads to economic losses. Hence, in the present study, a combined detection including a sensitive paper-based colorimetric device for the rapid determination of somatic cells (SCC) and electrochemical detection of β-hydroxybutyrate (BHB) in the milk samples has been developed. The working range was 1 × 105 to 2 × 106 for SCC and 0.05 to 2.5 mM BHB in which the normal and extreme cases of mastitis and ketosis values exist. The detection method is based on reaction using substrate 5-Bromo-indoxyl acetate (5BIA) and enzyme (BHB dehydrogenase) for the enzymes (esterase) and substrate (BHB) present in the milk samples during mastitis and ketosis respectively. An increase in blue color development was associated with an increase in the number of SCC; likewise, the increased voltage denoted the increase concentration of BHB in the samples. The repeatability was evaluated, and the % relative standard deviation (RSD) value <8.0 (n = 12). The limit of detection (LOD) was close to that achieved by a desktop spectrophotometer. The applicability of the developed kit demonstrated good sensitivity that can be deployed for other biological samples of interest. The proposed method provides a rapid, sensitive and promising tool for the regular monitoring of cows as a point of care tests (POC) at the field level.
Keywords: Bovine; Dual-electrochemical-color testing device; Ketosis; Mastitis; Milk.
Copyright © 2019. Published by Elsevier B.V.