When you are rearing cattle, every now and again genetic defects raise their heads.

While many types of birth defects are manageable and are unlikely to be passed on to any progeny because of the recessive nature of mutations, others aren’t as viable for the farmer.

If your cow has a pelvic defect – for example if the tail head and spine drop down, making the pelvic opening very small, or a mass or other obstruction in the pelvis – this will lead to difficulties at calving.

If you’re lucky, you’ll be able to save the calf and cow by going in from the side for a c-section. Simply pulling the calf out by hook or by crook will be far too sore on the cow and the calf.

A Moocall calving sensor can help in this situation as you will know early if you need to intervene.

But if this is a genetic defect, you will not know about it until the cow has already had calves. This means the calf (if it survives the difficult birth at all) could be prone to pelvic problems of her own.

To make matters worse, you may not really notice until the second calving, because it is normal for first-calving heifers to have narrow pelvic openings and thus have difficult calvings.

Some would advise you to cull any cows with pelvic defects, and this is a bad expense if it emerges that both cow and progeny express these genes. This is especially true in a dairy herd.

In the cases of a severe pelvic defect you will know immediately. A congenital pelvic defect called ‘perosomus elumbis’ has been affecting an increasing number of Holsteins worldwide.

It is characterised by the absence of the caudal parts of the spine and spinal cord, i.e. lumbar, sacral and coccygeal spinal segments with associated musculoskeletal malformations of the hind quarters.