Cardiovascular phenotype analysis in large and abnormal offspring calves in relation to assisted reproductive technology†.

Large offspring syndrome/Abnormal Offspring syndrome (LOS/AOS) occurs at an increased frequency in calves derived from assisted reproductive techniques (ARTs). Specific criteria for LOS diagnosis in calves are lacking. Cardiac and vascular anomalies are common in ART derived neonates but have not been described in calves. Calves derived from in vitro produced (IVP) embryos and referred to Cornell University for prolonged gestation were prospectively enrolled. Calves underwent phenotypic evaluation and echocardiography. Two-dimensional, M-mode, and color flow mapping echocardiography was performed to evaluate cardiac structure and function. Phenotypic vascular anomalies were recorded. Seven calves were included in this study: four females and three males. The mean weight was 60.4 kg (range 50-74 kg). All seven calves were confirmed to have flow across the foramen ovale with distensible atrial septal membranes. A patent ductus arteriosus (PDA) was seen in 6/7 calves and could not be evaluated in one calf but auscultation was consistent with a PDA. Subjectively, all calves had evidence of right ventricular wall hypertrophy and chamber enlargement. Enlarged umbilical vessels were also noted at the time of cesarian section. LOS/AOS calves with prolonged gestation have abnormal cardiac phenotypes including large foramen ovale with thin and abnormally distensible atrial septa.