Antimicrobial prophylaxis post-amniocentesis procedures in cattle: A randomized controlled equivalence study

Abstract

Amniocentesis is a routine procedure utilized on several species including human, equine, and bovine patients. Early assessment and discovery of new genetic traits in the cattle industry are highly desirable in order to accelerate genetic gain by shortening generational intervals. One of the main concerns from this procedure is the introduction of pathogenic bacterial contamination into the amniotic cavity thereby increasing the risks of spontaneous pregnancy losses post procedure. In this randomized controlled equivalence study, we have tested the effect of antimicrobial prophylaxis on the incidence of spontaneous abortions and contrasted it to untreated individuals post amniocentesis. On the treated group (n = 67) all heifers remained pregnant whereas 1 of the untreated group (n = 65) resulted in a spontaneous abortion during the study period. The latter represents 1.54% of pregnancy losses attributed to the risk associated to the amniocentesis procedure. However, the probability of inducing spontaneous abortion from the technique itself is not different to that of the contemporaneous population (n = 694) not undergoing amniocentesis viz., 1.59%. Following a two-tailed distribution, statistical analyses showed no significant differences across treatments (Fisher's exact test P = 0.49). The current prospective study indicates that performing amniocenteses on cattle have resulted in similar spontaneous pregnancy losses comparable to those of pregnant heifers without undergoing amniocentesis and regardless of antimicrobial use. In conclusion, prophylactic antimicrobials may not be applicable within the cattle amniocentesis framework.

Keywords: Amniocentesis; Antimicrobial prophylaxis; Bovine.

Fig. 1

Schematic illustration of the study period. Enrolled nulliparous heifers were bred either by artificial insemination or embryo transfer techniques. Chronological sequence starts at D0 which corresponds to the reference heat. Moreover, animals not being bred during D0 were eligible for embryo transfer at D7. Fetal gender and subsequent amniocentesis sessions were performed at D60 and at D68, respectively. In this study, n = 67 heifers were treated with prophylactic antimicrobials and, n = 65 remained untreated as the control group. After amniocenteses, all animals were closely monitored during the following days to observe any spontaneous abortion. Animals had one last pregnancy check by ultrasonography ∼ 4 weeks post amniocentesis procedures which corresponded to ∼100 days of gestational age.