Gastroparesis syndrome in dairy heifers
Typical presentations of gastroparesis include progressive abdominal distension and loss of both condition and appetite.
Since the second quarter of 2022 the UK Surveillance Network has reported cases of apparent gastroparesis in nine to twenty four month-old, Holstein Friesian, bulling and in-calf dairy heifers. To date the majority, or all, of the affected heifers have had the same sire.
The heifers typically present with progressive abdominal distension and condition loss, become inappetant, are non-responsive to treatment, and have had to be euthanised. No obvious dietary or management risk factors have been identified. APHA has received either submissions or reports related to at least fifteen affected farms in the UK so far and there are likely to be more.
At postmortem examination, the abdomen and the rumen are markedly distended, and the ruminal contents have a distinctive frothy texture. Abomasal impaction and/or ulceration has also been a feature of some of the cases. One of the affected farms uses a cow monitoring system, which records rumen function, and the outputs demonstrated markedly reduced, and eventually absent, rumen contractions at the time when the clinical signs became apparent and then worsened.
The breeding company has been working with partners across the UK disease surveillance network, private vets, and a specialist genetic research team in France since May 2022. At the time of writing, the mechanism underlying this syndrome is uncertain. The gross pathological and histopathological findings of the cases have so far been inconclusive.
The appropriate blood and tissue samples have been collected from affected and non-affected (control) animals. These are currently being analysed to try and uncover the precise genetic mechanism of the issue and, will hopefully aid better understanding of this syndrome.
The working hypothesis is that the sire carried a de novo (new) mutation that is inherited in a dominant fashion. There appears to be mosaicism of the bull’s germ cells, where there is more than one genetic line of the germ cells (as the result of genetic mutation), and the condition appears to develop in approximately 25% of his offspring. It is thought that animals sired by this bull which are functioning normally beyond their first calving, are unlikely to have inherited the mutation, and therefore may remain healthy and possibly not transmit this fatal condition.
The bull has been removed from AI service and his semen has been removed from the market. He does not have any sons in AI service. The breeding company will contact customers directly who bought this bull’s semen. Farmers that suspect they have experienced cases, but that have not yet been approached by the breeding company, should contact the breeding company directly.
Posted by SRUC Veterinary Services on 28/04/2023