![]() Non-infectious causes are usually related to a low rate of abortion. However, several non-infectious aetiologies can be associated with abortions in sheep, such as traumatism, pregnancy toxaemia, vitamin E/Se deficiency, stressful handling, overcrowding, or even consuming toxic plants (Youngquist and Threlfall 2006 Pugh and Baird 2012). Infectious causes, which are more rapidly diagnosed, are more critical (Njaa 2011). Non-infectious causes remain unknown in most abortions because they do not produce a high percentage of aborted ewes and therefore are not studied in depth. There are various potential agents underlying the causes of abortion, which can mainly be classified into infectious and non-infectious. Therefore, in the present study, an abortion outbreak was considered when the total percentage of abortions exceeded 2%. In most sheep flocks, the percentage of ewes visibly aborting is less than 2% (Menzies 2011), being this considered a normal rate. Some of these indirect costs are related to an increase in lambing intervals, which supposes more food expenses, a detriment in the incomes of sold muttons, fewer replacement lambs available and an increase in veterinary treatments (Pugh and Baird 2012). Financial losses are associated with both direct and indirect costs. 2017).Ībortions can result in significant economic losses and severe risks to public health. However, the last two are not mandatory (Esmaeili et al. In addition, its zoonotic potential can pose a serious risk to public health.Īccording to Iran Veterinary Organization (IVO) protocols, Iranian sheep health plans include vaccination against brucellosis, sheep pox, Peste des Petits Ruminants (PPR), anthrax, Foot-and-mouth disease (FMD), contagious agalactia and enterotoxemia. Due to these reasons, sheep abortions severely affect food production, animal health and the agricultural economy. Milk is also a vital product for Iranian sheep, producing 252,000 tons/year, providing for a large part of the population (Ministry of agriculture 2020). Mutton meat is essential in food self-sufficiency and supplies a sound animal protein source. The primary purpose of the Iranian breeds is meat production, which leads to an annual production of 265,000 tons (Ministry of agriculture 2020). Iran has more than 30 indigenous breeds of sheep with a population of 45 million heads (Ministry of agriculture 2020). Small ruminants have a significant role in the Iranian agricultural economy and perform as leading actors in the field of the livelihoods of nomadic and rural farmers (Esmaeili and Hamedi 2018). Further studies are necessary to evaluate if these factors are similar to other countries in the same region. Results revealed multiple causes of abortion outbreaks among Iranian sheep flocks, which need careful investigation to identify possible aetiology and risk factors. On the other hand, non-infectious agents such as trauma, pregnancy toxaemia and vitamin E/Se deficiency were involved in those flocks with low abortion rates (less than 10%). Infectious agents such as Coxiella burnetti (22.7%), Chlamydia abortus (12.3%) and Brucella melitensis (10.4%) were the most frequently isolated in the investigated flocks, with more than 2% of abortion rates. In this sense, parity, gestational age of the aborted fetus, vaccination protocol, mineral supplementation and history of stillbirth showed significant associations with abortion. Data were analysed using univariate tests and multivariable binary logistic regression analysis. A checklist containing general animal information for each abortion outbreak evaluated was filled in. ![]() In this cross-sectional survey, causes of abortion were evaluated in 757 sheep flocks, and risk factors were analysed. This survey assessed the infectious and non-infectious causes of abortion in Iranian sheep flocks and determined the main risk factors. It can result in significant economic losses and a severe public health risk. ![]() Abortion is a major issue in sheep husbandry.
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