母牛发情周期和妊娠早期宫颈-阴道粘液电导率变化规律的研究

 本文应用自行设计安装的MFR-1型母牛发情鉴定及早期妊娠诊断仪，将特制探测电极插入母牛阴道穹窿部，测定了94头母牛宫颈-阴道粘液的电导率（CVMEC）。结果表明，母牛在发情周期和妊娠早期CVMEC呈规律性变化。发情周期正常的母牛，CVMEC在间情期处于较低水平（5.64mS/cm），前情期开始上升（8.93mS/cm），发情期达峰值（13.40mS/cm），后情期开始下降（9.84mS/cm），最后降至间情期水平。输精后，未妊与妊娠母牛CVMEC的变化规律不同。在发情周期的各时期，未妊母牛高于妊娠母牛；未妊母牛在输精后21天左右返情，CVMEC再度出现峰值；妊娠早期母牛则保持与间情期相近的较低水平（5.08mS/cm）。笔者认为，母牛CVMEC的规律性变化的生理学基础是体内激素水平和宫颈-阴道粘液的周期性变化，据此进行发情鉴定和早期妊娠诊断是可行的。与目前使用的方法相比，CVMEC法更具有实用价值。

CHANGES OF ELECTRICAL CONDUCTIVITY OF CERVICO-VAGINAL MUCUS IN DAIRY COWS DURING ESTROUS CYCLE AND EARLY PREGNANCY

Changes of cervico-vaginal mucus electrical conductivity (CVMEC) were measured in 94 dairy cows during estrous cycle and early pregnancy with a probe inserted into the vaginal fornix every day or every three days for 37 days. The regularity of changes in CVMEC was related to the changes in estrous cycle. The highest value (13.40mS/cm) occurred during estrus, fhe lowest one (5.64mS/ cm) during diestrus, and during proestrus (8.93mS/cm) and metestrus (9.84mS/cm) The values were considerably lower than those in estrus and higher than thosein diestrus. Following insemination the CVMEC in non-pregnant cows was higher than that in pregnant cows during the stages of estrous cycle.When non-pregnant cows returned to estrus at around 21 days post-service, it reached a maximum value again.However, throughout early pregnancy, it maintained a low level (5.08mS/cm) similar to that in diestrus phase. It is obvious that the change was based upon the cyclical changes of hormones and cervicovaginal mucus. Using CVMEC method for detection of estrus and early pregnancy in dairy cows is practical at present.