Congenital heart defects in two italian simmental (Pezzata Rossa Italiana) calves
Congenital heart diseases (CHDs) are the consequence of anomalies during the embryonic development of the heart and are defined as rare in cattle with scarce reports in the literature. The ventricular septal defects (VSDs) and the atrial septal defects (ASDs) are reported to be the most common, followed by other different malformations such as patent ductus arteriosus (PDA).
The aetiology of the CHDs has not been fully explained yet, but is commonly considered linked to either inherited or non-inherited causes. Although uncommonly reported, the inherited congenital anomalies could affect different breeds of cattle with a potential significant economic impact. In addition, the wide use of the in vitro fertilization could be associated with a potential reduction of genetic variability in bovine population, therefore favouring the development of congenital defects such as CHDs.
Among the non-inherited causes, foetal viral infections (e.g. Schmallenberg virus, Bovine diarrhea virus, Blue Tongue virus), nutritional deficiencies of the dam and toxic agents play a key role in the development of CHDs.
The two cases herein described report the occurrence of cardiac congenital malformations in Italian Simmental breed (Pezzata Rossa Italiana, PRI) calves. In the first case, the ASD was accompanied by concurrent anomalies in other organs (liver and brain); in the second case, the calf presented both PDA and ASD. Based on the anamnestic data and the laboratory results, a possible role of viral agents seems to be unlikely. The investigation and determination of the possible causes of CHDs is challenging both for veterinary practitioners and laboratory diagnosticians due to the huge range in the severity of clinical signs, to the lacking of pathognomonic signs and to the possible absence of clinical signs until adulthood. The description of congenital malformations aimed to focus on these rare pathologies in order to collect information and to monitor their presence and diffusion in the bovines, especially in the PRI breed where these CHDs were not previously reported.