A survey of biosecurity measures applied on dairy cattle farms in Spain

Attention to biosecurity has been highlighted as the most important measure to reduce and prevent the introduction of diseases to farms. There is little published information about the biosecurity of dairy cattle in Spain. We therefore aimed to assess and characterize the current application of biosecurity measures on dairy cattle farms in Spain, and relate these to bovine viral diarrhea and infectious bovine rhinotracheitis. From July 2017 to April 2018, data on biosecurity measures for 124 dairy herds were collected using a questionnaire. We also assessed the sanitary status of these farms (efficacy of measures implemented against both diseases using antibody ELISA. Data were analyzed descriptively, and using multiple correspondence analysis and a two-step cluster analysis. Measures to prevent disease introduction were often poorly implemented. Three main clusters of farms were identified: Clusters 1 and 2 included herds of small and intermediate sizes, respectively. These, particularly cluster 1, showed the most deficiencies in the control of vehicles and visitors. However, individual purchases usually involved low numbers of animals, especially in cluster 2, and animals were tested for bovine viral diarrhea and infectious bovine rhinotracheitis at their places of origin or on arrival at farms. Farms in clusters 1 and 2 were frequently under voluntary control programs. Cluster 3 had the largest herd sizes, with somewhat better biosecurity control of vehicles and visitors. However, farms in this cluster also purchased the most animals, sometimes without testing, and hired external workers most often. Farms in cluster 1 showed the best sanitary level, followed by clusters 2 and 3. Collecting data such as these is an important first step to identification of biosecurity shortcomings, and to structuring of adequate follow-up to ensure that measures are implemented correctly on farms in Spain.


Introduction
Infectious agents that affect livestock may be transmitted by various routes such as live 57 infected animals, trucks and other vehicles, people, aerosols, fomites, or wildlife or 58 insect vectors. Thereby, prevention through biosecurity is the most cost-effective 59 protection (1). 60 Within the context of animal production, biosecurity is defined as management 61 activities that reduce the opportunities for infectious agents to gain access to, or spread 62 within, a production unit (2).Thus, it has two main components: external and internal Commission. The aim was to focus on preventive measures, disease surveillance, 71 controls, and research to reduce the incidence of animal diseases and minimize the 72 impact of outbreaks (4). 73 The putative benefits of undertaking biosecurity for disease prevention and/or 74 control include improvements in production efficiency (hence greater profits), animal 75 welfare, immune responses to vaccines, and job satisfaction for producers, herd health 76 professionals, and other agricultural workers (5). In addition, in pig herds, a link 77 between biosecurity and antimicrobial treatment-related criteria has been demonstrated 78 and quantified (6).

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Despite these benefits, implementation of biosecurity on dairy cattle farms is 80 often sub-optimal, and poor or inappropriate knowledge transfer is often cited as a 81 potential cause of disease spread (7).The main limitations and strengths of the 82 biosecurity measures applied in dairy cattle farms have been studied recently in several 83 countries (7-10), as a preparatory step to develop greater awareness of the importance of 84 each measure and the factors that might restrict its application. In Spain, despite the 85 economic importance of milk production in some regions, current biosecurity practices 86 on dairy farms have not been studied empirically although a recent study assessed 87 perceptions and practices applied by rural veterinarians (11).

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The sanitary status of dairy cattle farms with respect to endemic diseases such as 89 bovine viral diarrhea (BVD) and infectious bovine rhinotracheitis (IBR) is highly 90 variable among Spanish regions. In some, the situation is unknown and the approach to

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The aim of the present paper was to assess and characterize the current

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Area description and herds surveyed 106 We conducted our study in two Autonomous Communities (AC) of Spain: Galicia 107 (NW), and Catalonia (NE). Galicia is the main dairy cattle area of the country, with 108 55% of the farms and 38% of the milk production. The mean herd size per farm is 43    The questionnaire, which is available in Spanish on request from the authors,     Vehicles visiting the farms represented an infection risk for most of the surveyed 208 farms, because nearly all vehicles entered inside the perimeter of all farms (Table 3).

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The most frequently entering vehicles were feeder wagons, followed by those collecting   Control of visits and staff also showed room for improvement ( The MCA with standardized data explained 38.9% of the variance in biosecurity  These farms purchased animals less frequently than did those in other clusters.

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When they did so, purchases often entailed few animals that were tested, usually at their 261 origin, against BVDV and BoHV-1. This was also the cluster with more control over nearly 93% of visitors that have contact with the animals do not use protective clothing.

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A similarly lack of implementation of biosecurity measures has been observed 300 on dairy farms elsewhere in Europe (7,11,20). The implementation of biosecurity plans

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In contrast, cluster 3 included the largest herds in our study, located in Catalonia.

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Herd size has been previously described as a cluster variable for several biosecurity outbreaks. Thereby, the risk they could pose is unknown.

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The influence of our methodology on these results must be considered.