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Sheep

Sheep abortion – a roundtable discussion

01 September 2021
Clinical
26 mins read
Figure 7. Agriculture and Horticulture Development Board (AHBD) estimates of rates of vaccination for ovine abortion. Courtesy of Kynetec, MSD and AHDB Vaccine Report.
Figure 7. Agriculture and Horticulture Development Board (AHBD) estimates of rates of vaccination for ovine abortion. Courtesy of Kynetec, MSD and AHDB Vaccine Report.

Abstract

Foreword

Abortion takes a heavy toll on the sheep industry, not only economically, but in emotional terms too. Enzootic abortion in ewes is consistently the most frequent diagnosis followed in descending order by infection with Toxoplasma gondii, Campylobacter spp., Salmonella spp. and Listeria spp. Causes of abortion also lead to increased barren rates, and the birth of weak lambs, so the impact of these pathogens is greater than just abortion. Fortunately there are vaccines for the two most common causes of abortion, providing farmers and the veterinary surgeons advising them with effective and sustainable tools in the control of enzootic abortion and toxoplasmosis. The uptake of these vaccines, however, remains lower than might reasonably be expected. In this roundtable discussion the barriers to the implementation of the extant measures of abortion control were discussed and suggestions made as to how abortion can better be prevented.

Losses associated with ovine abortion have a significant impact on the profitability of sheep farms. Further losses, with the same aetiologies as the abortions, occur as a result of weak, illthrift lambs that are born alive but may die or require the input of time and expense to survive. Lamb growth rates are impacted, further reducing profitability. Abortion has a negative impact on the health and welfare of both the flock and those working with it. Many of the agents that cause abortion have the potential to cause serious human physical illness, and losses at lambing can have a significant impact on the mental health of those working with the flock. The annual incidence of abortion is estimated to be 2–3% (Mearns, 2007a) and abortion accounts for 30% of total lamb losses (Figure 1, Hybu Cig Cymru (HCC) lambing project). The annual cost of chlamydial abortion alone to the UK sheep industry has been estimated to be £11–48 million per year (Bennett and IJpelaar, 2005) and the total cost from all causes of abortion collectively can reasonably be expected to be more than double these figures.

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