Heckman G S, Katz L S, Foote R H, Oltenacu E A, Scott N R, Marshall R A
J Dairy Sci. 1979 Jan;62(1):64-8. doi: 10.3168/jds.S0022-0302(79)83203-8.
An electronic probe with parallel stainless steel electrodes was designed to measure changes in electrical resistance in the anterior vagina associated with increased cervical mucus secretion at estrus. Three groups of Holsteins were probed, and a sample of residual milk after milking was taken for progesterone assay every 2nd day for 28 to 40 days. Group I consisted of 29 cycling virgin heifers, Group II consisted of 24 lactating cows in the Cornell herd, and Group III consisted of 62 lactating cows in three commercial herds. Lactating cows were 26 or more days postpartum when sampling began. In Group I, 77% of the measurements at the ventral surface of the anterior vagina were lowest on the day of estrus and correlated well with days KaMaR Heatmount Detectors were triggered or chalk was erased. In Groups II and III, average electrical resistance also was minimal at estrus and was correlated .92 to .99 with average milk progesterone during the 4 days preceding and including estrus. The electronic probe appears to enable one to detect which cows are cycling normally and to aid in determining when to expect estrus.
设计了一种带有平行不锈钢电极的电子探头，用于测量发情期宫颈黏液分泌增加时阴道前部电阻的变化。对三组荷斯坦奶牛进行了探测，并在28至40天内每隔一天采集一次挤奶后的残留乳样进行孕酮测定。第一组由29头处于发情周期的未孕小母牛组成，第二组由康奈尔牛群中的24头泌乳母牛组成，第三组由三个商业牛群中的62头泌乳母牛组成。开始采样时，泌乳母牛已产后26天或更长时间。在第一组中，阴道前部腹面77%的测量值在发情当天最低，并且与卡玛发情监测器触发或粉笔标记被擦除的天数密切相关。在第二组和第三组中，发情期的平均电阻也最小，并且与发情期及发情期前4天的平均乳孕酮水平的相关性为0.92至0.99。电子探头似乎能够使人们检测出哪些奶牛发情正常，并有助于确定发情的时间。
