Congenital abnormalities are those that are present at birth. In cattle, it is estimated that 0.5%–1% of calves are affected by congenital defects however, such estimates probably grossly underestimate true prevalence due to inaccurate recording.
The ICBF/Teagasc congenital defect survey continues to collect valuable data regarding the incidence of abnormalities in calves at birth. An analysis of over 500 reports submitted by survey participants over a 10 year period, indicated that the most commonly reported defect was intestinal atresia (water-belly) (24.3%), followed by multiple defects (at least two defects in the same animal) (19.9%), and tail abnormalities (13.4%).’ Atresia has consistently been reported as a frequent defect in Irish cattle. The analysis indicated that the majority of calves with atresia were male (66%), consistent with previous Irish studies. This study also found that 3.5% of atresia cases were reported as a twin and in 13.6% of atretic calves, a co-defect was reported, most commonly a tail defect. More information can be found here (page 274-275): https://teagasc.ie/wp-content/uploads/uploads/One-Health-One-Welfare.pdf
Survey results from the first half of 2025 consisting of over 150 participants, indicate that the most common abnormalities observed by farmers were 1) leg deformities (ankylosis, locomotor disorder, joint laxity) (24%), 2) multiple defects (14%), and 3) intestinal atresia (water-belly) (13%). The increase in the reporting of leg defects this Spring, may be as a result of the increase in calves exposed to Schmallenberg virus (SBV) and may reflect the outbreak of SBV seen nationally. These findings support the use of this survey as a national dairy and suckler syndromic surveillance tool to detect other possible disease outbreaks such as BVD or Bluetongue.
The routine recording of congenital defects by veterinary practitioners, pathologists, farmers and researchers is a collective approach that can be taken to identify abnormal phenotypes, provide improved estimates of their prevalence and contribute to research on possible genetic solutions. Thanks to all farmers and veterinarians who take the time to participate in this ongoing survey.
The survey can be found here: Birth defect survey
Disclaimer: To preserve the integrity and intent of this article, please contact Katie Quigley (ICBF) before quoting or referencing. This helps ensure the information is presented accurately and in the correct context. Email: [email protected]