Displaced Abomasum in Cattle

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The abomasum is the 4th, or ‘true’ stomach of the cow.  It usually lies low near the floor of the abdomen.  Displacement is when the abomasum is shifted from its normal anatomical location, to either left (LDA) or right (RDA).  Usually atony (lack of stomach tone or contractions) and gas production cause the change. Left displaced abomasum is more likely with 80-90% of displacements being LDA.  It is most common in large breed dairy cattle, but theoretically may occur in any bovine.  Right displaced abomasum is less common and more serious – as well as moving up the right side of the cow, the abomasum may also rotate on itself causing a life threatening toxaemia.  Both displacements will affect the flow of digesta (food) leading to various clinical signs noted later.

Cows in early lactation are at greatest risk of a displacement, with most LDA cows seen in the 2-6 week period after calving.  50-80% are diagnosed within 2 weeks, 80-90% within 1 month.  LDA cattle will often refuse to eat concentrates, but still pick at forage and grass.  Concurrent disorders are common – ketosis, RFM, mastitis, metritis, milk fever and lameness issues are all increased risks for LDA.  These cows are generally affected over the course of a few days.  Milk drop is a feature, but the condition may wax and wane for a short period as the LDA can change in size and degree of displacement.  Primary Ketosis is a risk factor for displacement development, but secondary Ketosis is always seen with a displacement.

RDA cattle are more acutely sick.  They usually go straight off milk and feed, and may not have had other health issues.  When the abomasum twists, the cow will become toxic and soon die.  A straightforward RDA is a candidate for surgery with a good chance of success.  A twisted RDA and the sickness it brings is more complicated to treat, and carries a far higher chance of failure.  For this reason, an RDA should really be classed as an emergency and treated as such.

Any animal that goes off food or milk should really be seen – similarly, if an apparently simple issue brings production or condition down further than expected – let us know!

As we have seen, the usual trigger for displacement is calving.  This is due to the reduction in feed intake around calving.  If a dry cow is not eating enough forage, the rumen fill is low, rumen motility is reduced, and this in turn reduces abomasal mobility and emptying.  Fat cows are also a risk – these show a greater DMI (dry matter intake) depression prepartum (pre-calving). In addition to affecting rumen fill this also leads to increased risk of ketosis and fatty liver, causing further reduction in DMI and therefore susceptibility to sickness around calving due to NEB (negative energy balance).

Dry cow management is essential to reducing displacements.  Herd incidence of displacements should be 1% or lower.  Accurate calving dates allow best management of dry cows.  Lead feeding and a high percentage of dry matter as forage will help tremendously – this is a disease secondary to something, and that something is usually a poor diet or transition management.