Evaluation of salivary electrolytes during estrous cycle in Murrah buffaloes with reference to estrus detection

Timely estrus detection is one of the critical factors for increasing reproductive efficiency in buffaloes. In recent decades, saliva has become a more popular as a noninvasive source for determining physiological status of animals by various biochemical electrolytes. This study was designed to assess and correlate changes in different salivary minerals concentration (calcium, inorganic phosphorus, magnesium, sodium, potassium, and chloride) during different stages of the estrous cycle in Murrah buffaloes.

The saliva samples were collected during the different phases of the estrous cycle from 20 Murrah buffaloes in early morning hours and were assayed using respective minerals assay kits.

The concentrations of calcium (8.76±0.08-12.11±0.11 mg/dl), inorganic phosphorus (6.56±0.13-14.72±4.50 mg/dl), magnesium (2.27±0.14-5.79±0.15 mg/dl), sodium (139.47±0.31-159.62±1.22 mmol/L), potassium (12.40±0.22-26.85±1.22 mmol/L), and chloride (109.28±0.41-137.07±0.68 mmol/L) varied during the different phases of estrous cycle. The concentration of calcium, inorganic phosphorus, magnesium, sodium, potassium, and chloride in saliva were significantly (p<0.01) higher during estrus phase compared to other phases of the estrous cycle. All these minerals were positively and significantly (p<0.0001) related to estrogen concentration while salivary concentrations of calcium, magnesium, sodium, and chloride showed a significant (p<0.0001) negative correlation with progesterone level in blood plasma.

These preliminary findings indicate that there are definite variations in salivary mineral and electrolyte concentrations during different phases of the estrous cycle. These results may be used as an aid for estrus detection/confirmation in buffaloes although validation of the results using a large number of animals is required.