Early pregnancy diagnosis by palpation per rectum: influence on embryo/fetal viability in dairy cattle

The objective was to estimate the effect of palpation per rectum (for early pregnancy diagnosis) on embryo/fetal viability in dairy cattle. A controlled, randomized block-design experiment with two blocks, one by category, and the other by number of embryos, was conducted. Five-hundred-and-twenty pregnant dairy cows and heifers with a viable embryo detected by transrectal ultrasonography (TRUS) between days 29 and 32 after AI were included. The pregnant females were randomly allocated into two nearly equal groups: palpation per rectum (PAL group; n=258) and no palpation per rectum (NPAL group; n=262). The PAL group was submitted to palpation per rectum (PPR) using the fetal membrane slip (FMS) technique once between days 34 and 41 of pregnancy. The fetal membrane slip consisted of compressing the pregnant uterine horn and allowing the chorioallantoic membrane to slip between the fingers. Both groups were submitted to two additional TRUS at days 45 and 60 of pregnancy, to monitor the potential immediate and delayed deleterious effects of PPR on embryo and fetal viability, respectively. A diagnosis of embryo/fetal death was made when there was no embryo/fetal heart beat or the absence of positive signs of pregnancy in an animal previously diagnosed pregnant, or the presence of signs of embryo/fetal degeneration. The overall rate of embryo/fetal death was 14.0% (73/520). Embryonic death (10%; 52/520) was higher than fetal death (4.5%; 21/468; P<0.001). Embryo/fetal mortality was higher in cows (16.4%; 59/360) than in heifers (8.8%; 14/160; P<0.025) and in cattle with twin (25.5%; 12/47) versus singleton pregnancies (12.9%; 61/473; P<0.025), but was not different (P>0.05) between PAL (14.7%; 38/258) and NPAL (13.4%; 35/262). In conclusion, PPR between days 34 and 41 of pregnancy using the fetal membrane slip technique did not affect embryo/fetal viability.