Transcutaneous ultrasound over the right flank to diagnose mid- to late-pregnancy in the dairy cow

Objective   To investigate the practical application and image quality of transcutaneous ultrasonography across the right flank for the diagnosis of mid- to late-gestation in cattle.
Procedure   Dairy cows of known pregnancy status were used to establish criteria for the identification of mid- to late-stage pregnancy by transcutaneous ultrasonography. Factors involved in the practical application of transcutaneous ultrasound for routine use in pregnancy diagnosis in dairy cattle were also examined.
Results   Transcutaneous ultrasound, using a 3.5-MHz sector transducer applied over the caudodorsal right flank fold, allowed rapid and detailed visualisation of bovine pregnancy (i.e. fetus, fetal fluids, placentomes and/or fetal membranes) and could be used to establish criteria for the diagnosis of pregnancy. The commonly available cattle holding facilities of the herringbone dairy, rotary herringbone dairy, AI race or crush, and walk-through dairy all allow safe access to the right flank of a dairy or beef cow. However, transcutaneous scanning over the right flank is difficult in modern rotary turnstile dairies.
Conclusion   A 3.5-MHz sector transducer applied over the caudodorsal right flank fold allows detailed visualisation of the bovine fetus in most types of cattle-holding facilities. Further investigation of the sensitivity and specificity of this technique over the entire gestation period and its possible use in ageing of the bovine fetus is merited.