Research in the Sept. 1, Journal of the American Veterinary Medical Association provides some answers.  

Looking at almost 1,000 dairy cows in one study, researchers tried to determine the effect of palpation per rectum by use of 1 or 2 fetal membrane slips for pregnancy diagnosis during early gestation on pregnancy loss in dairy cattle.

All cattle were determined to be pregnant by use of ultrasound at about day 31 after heat and randomly allocated into two groups (a control group with 476 cows and a palpation group with 452 cows).

The control group was not subjected to pregnancy diagnosis via rectal palpation.

The palpation group was subdivided into two groups, one palpated with one membrane slip and one palpated with two membrane slip examinations performed by one veterinarian between days 34 and 43 after estrus.

All cattle were reevaluated by ultrasound on days 45 and 60 to determine viability of the embryo and fetus.

Overall, pregnancy loss between 31 and 60 days was 14.1 percent. Pregnancy loss for the control, one-slip, and two-slip groups from days 31 to 60 was 14.5 percent, 12.6 percent, and 14.9 percent, respectively.

Embryonic loss for the control, one-slip and two-slip groups was 12.4 percent, 9.1 percent, and 9.5 percent, respectively. Fetal pregnancy loss for the same groups was 2.4 percent, 3.8 percent, and 5.9 percent, respectively.

The researchers concluded that pregnancy diagnosis by one or two fetal membrane slips performed during palpation in early gestation did not increase pregnancy loss in dairy cattle.

Source: Washington State University Veterinary Extension Quarterly Newsletter