Data analysis supports monitoring and surveillance of goat health and welfare in the Netherlands

Monitoring and surveillance systems have an increasingly important role in contemporary society ensuring high levels of animal health and welfare, securing export positions, and protecting public health by ensuring animal health and product safety. In the Netherlands, a voluntary monitoring and surveillance system is in place since 2003 to provide a broad overview of livestock trends in addition to disease-specific surveillance systems, including insight into the occurrence and prevalence of new and emerging non-notifiable diseases and disorders. Being a major surveillance component of this monitoring and surveillance system for small ruminant health in the Netherlands, an annual data analysis on routine census data is performed to retrospectively monitor trends and developments regarding goat health and welfare. This paper aims to describe the process of the data analysis on goat farms in the Netherlands in 2020 and subsequent results are discussed. The data analysis provides key monitoring indicators such as animal and farm density, mortality, animal movements, and numbers and origin of imported small ruminants. Trends were analysed over a five-year, period and associations between herd characteristics and herd health are evaluated. Results showed that in 2020 the Dutch goat population consisted of 670,842 goats, distributed over 14,730 unique herds and increased by 2.3 % compared to 2019. Between 2016 and 2020, although probably underestimated, recorded mortality rates showed a decline on both small-scale and professional farms, with a strongest decrease on farms with herd sizes over more than 200 animals. Seventy-five percent of all professional farms registered animal introductions, in addition to 63 % of small-scale farms, including 2439 imported goats. Performing risks analyses requires demographic knowledge of the goat industry. During and after several disease outbreaks, such as bluetongue and Schmallenberg virus disease, the data analysis proved to function as a valuable tool, however, appeared just as important for recording outbreak-free data. Since its start in 2006, the concept of the data-analysis has continuously been improved, and will in the future be further developed, especially if more complete data sets become available. Subsequently, data analysis will increasingly support monitoring and surveillance of goat health and welfare.

Abortion in small ruminants in the Netherlands between 2006 and 2011

During five successive lambing seasons between 2006 and 2011, 453 submissions of abortion material, 282 of ovine and 171 of caprine origin, were examined at the Animal Health Service in the Netherlands. Infectious agents as the most plausible cause of the abortion were found in 48 percent of the ovine submissions and in 34 percent of the caprine submissions. Submission of both aborted fetus and placental membranes increased the diagnostic yield of laboratory investigations (17 percent and 21 percent for ovine and caprine submissions, respectively). The main infectious causes of abortion in sheep were Chlamydia abortus, Campylobacter spp., Toxoplasma gondii, Listeria spp., and Yersinia pseudotuberculosis. The main infectious causes of abortion in goats were Coxiella burnetii, Chlamydia abortus, Listeria spp., Toxoplasma gondii, and Campylobacter spp. In 42 percent of the ovine and in 56 percent of the caprine submissions a causal agent was not identified. Furthermore, in 12 percent of the ovine and 10 percent of the caprine submissions evidence of placentitis, indicative of an infectious cause of the abortion, was found, but no infectious agent was identified. Most infectious causes of ovine and caprine abortion have zoonotic potential. Humans, especially pregnant women, who are in close contact with lambing sheep or goats should be aware of the importance of precautionary hygiene measures.

Coxiella burnetii in bulk tank milk samples from dairy goat and dairy sheep farms in The Netherlands in 2008

In 2007, a human Q fever epidemic started, mainly in the south eastern part of The Netherlands with a suspected indirect relation to dairy goats, and, to a lesser degree, to dairy sheep. This article describes the Q fever prevalences in Dutch dairy goat and dairy sheep bulk tank milk (BTM) samples, using a real-time (RT) PCR and ELISA. Results of BTM PCR and ELISA were compared with the serological status of individual animals, and correlations with a history of Q fever abortion were determined. When compared with ELISA results, the optimal cut-off value for the RT-PCR was 100 bacteria/ml. In 2008, there were 392 farms with more than 200 dairy goats, of which 292 submitted a BTM sample. Of these samples, 96 (32.9 per cent) were PCR positive and 87 (29.8 per cent) were ELISA positive. All farms with a history of Q fever abortion (n=17) were ELISA positive, 16 out of 17 were also PCR positive. BTM PCR or ELISA positive farms had significantly higher within-herd seroprevalences than BTM negative farms. In the south eastern provinces, the area where the human Q fever outbreak started in 2007, a significantly larger proportion of the BTM samples was PCR and ELISA positive compared to the rest of The Netherlands. None of the BTM samples from dairy sheep farms (n=16) were PCR positive but three of these farms were ELISA positive. The higher percentage of BTM positive farms in the area where the human Q fever outbreak started, supports the suspected relation between human cases and infected dairy goat farms.

Epizootic of ovine congenital malformations associated with Schmallenberg virus infection

Epizootic outbreaks of congenital malformations in sheep are rare and have, to the best of our knowledge, never been reported before in Europe. This paper describes relevant preliminary findings from the first epizootic outbreak of ovine congenital malformations in the Netherlands. Between 25 November and 20 December 2011, congenital malformations in newborn lambs on sheep farms throughout the country were reported to the Animal Health Service in Deventer. Subsequently, small ruminant veterinary specialists visited these farms and collected relevant information from farmers by means of questionnaires. The deformities varied from mild to severe, and ewes were reported to have given birth to both normal and deformed lambs; both male and female lambs were affected. Most of the affected lambs were delivered at term. Besides malformed and normal lambs, dummy lambs, unable to suckle, were born also on these farms. None of the ewes had shown clinical signs during gestation or at parturition. Dystocia was common, because of the lambs' deformities. Lambs were submitted for post-mortem examination, and samples of brain tissue were collected for virus detection. The main macroscopic findings included arthrogryposis, torticollis, scoliosis and kyphosis, brachygnathia inferior, and mild-to-marked hypoplasia of the cerebrum, cerebellum and spinal cord. Preliminary data from the first ten affected farms suggest that nutritional deficiencies, intoxication, and genetic factors are not likely to have caused the malformations. Preliminary diagnostic analyses of precolostral serum samples excluded border disease virus, bovine viral diarrhoea virus, and bluetongue virus. In December 2011, samples of brain tissue from 54 lambs were sent to the Central Veterinary Institute of Wageningen University Research, Lelystad. Real-time PCR detected the presence of a virus, provisionally named the Schmallenberg virus, in brain tissue from 22 of the 54 lambs, which originated from seven of eight farms that had submitted lambs for post-mortem examination. This Schmallenberg virus was first reported in Germany and seems to be related to the Shamonda, Aino, and Akabane viruses, all of which belong to the Simbu serogroup of the genus Orthobunyavirus of the family Bunyaviridae. These preliminary findings suggest that the Schmallenberg virus is the most likely cause of this epizootic of ovine congenital malformations, which is the first such outbreak reported in Europe.