Fetal loss associated with palpation per rectum to diagnose pregnancy in cows.

A prospective observational study was performed to determine whether palpation per rectum of cows in the first 6 weeks of gestation to diagnose pregnancy contributed to fetal attrition. Pregnancy diagnoses were made by private practitioners as part of their routine herd-health service on 9 dairies in the San Joaquin Valley of California. To determine whether there was an association between abortion and fetal age at time of palpation, the probability of abortion was tested as a function of fetal age at palpation, controlling for possible modifying and confounding effects of herd, age at conception, gravidity, parity, and number of days-in-lactation at conception. Results of logistic regression analyses for 19,411 pregnancies followed for up to 90 days after palpation indicated that, during the 28- to 42-day period, palpation of fetuses earlier in the period was associated with a significantly (P < 0.0001) low probability of abortion, compared with that for palpation later in the period. An association between abortion and palpation of fetuses > 42 days of age was not found. Results were suggestive that, given conditions and techniques typical of private practice, fetal death may not be a usual manifestation of early palpation of cows to diagnose pregnancy, rather, that there may be a slight increase in risk of fetal death as the fetal age at palpation increases from 28 to 42 days.