The present study elucidated differences in movements of farm staff according to week of the BFS and weekday vs. weekend; and unit, namely towards farrowing, gestation/insemination, nursery and fattening unit. The following movements differed according to the week of the BFS: total number of daily movements (highest in insemination and farrowing week) and percentage of risky movements (highest in weaning week). There were more farm staff movements during a weekday, but the percentage of risky movements was for some farms higher and for others lower on a weekend day. The present study also gained more insight into movements towards the different units. There were more movements of farm staff towards the farrowing and gestation/insemination unit during insemination and farrowing week, compared to other weeks of the BFS. Movements towards the nursery and fattening unit did not differ according to the week of the BFS, except for the total number of movements towards the nursery in one farm and the percentage of risky movements towards the nursery unit in another farm.
The total number of daily movements significantly differed according to the week of the BFS for farms B, C, D, and E, all working in a 4-week system. On farm A, working in a 3-week system, there was no difference in the total number of daily movements according to the week of the BFS. A possible explanation could be that the main activities on the farm, i.e. weaning, insemination, and farrowing, are more evenly spread in a 3-week system, leading to a more even distribution of the movements over the different weeks. It is also noteworthy that the percentage of risky movements was the lowest on the farm using the 3-week system. This may be explained by the fact that the 3-week system allows for a better organization of the work throughout the weeks. In a 4-week system, there is one week with two main activities which demand extra work, i.e. insemination and farrowing, which could have led to a peak in the number of daily movements in that specific week of the BFS. Also in the weaning week there were many movements, likely because sows had to be moved from the farrowing to the gestation/insemination unit and piglets from the farrowing to the nursery unit.
According to the results of the Biocheck.UGent™ questionnaire, all farms except for farm B claimed to organize their work consistently starting with the young animals and then continuing the work in the older animals. However, the results of the present study did not confirm this, as a high percentage of risky movements was observed on the farms. This illustrates that monitoring the behavior of farmers is key to obtain accurate data, as farmers might not always provide the correct answer in observational studies. On larger farms, farmers should implement more biosecurity measures compared to smaller farms, because a larger number of animals also means that more animals can get sick and spread infections. Moreover, larger herds come more into contact with the outside world, e.g. by purchasing animals and livestock transport, increasing the risk of infection [20, 21]. In the present study, there were less risky movements on larger farms compared to medium-sized farms. On these large farms, there were more employees and it is possible that certain employees were only responsible for the work in certain units, resulting in less movements between the different units. Furthermore, previous studies in both pig [3, 22, 23] and cattle production [24, 25] have shown that biosecurity measures are better implemented in larger farms.
On farms A, B, and E, there were no significant differences in the percentage of risky movements according to the week of the BFS, meaning that the farmers applied a consistent working routine irrespective of the specific week of the BFS. Although there were no significant differences, the percentage of risky movements was high in all farms. Median values ranged from 9–33%, indicating that farmers often do not adhere to the biosecurity standards. This implies that there is much room for improvement. On farms C and D, there were significantly more risky movements in the weaning week. This was expected, as around the time of weaning there may be a lot of risky movements from the nursery to the farrowing unit.
In general, there were more movements on a weekday vs. a day on the weekend, and there are three possible explanations for this. The first one is that the BFS are well organized, and most activities are planned on weekdays. In both the 3- and 4-week system, weaning takes place on a Thursday, sows are inseminated on Monday, Tuesday, and Wednesday, and sows farrow on Thursday, Friday, and Saturday. Second, in farms D and E, there were several workers and they might have not been all present on the farm during the weekend, resulting in less movements on the weekend. Third, the work on the farm could be done more efficiently during the weekend to save time for other non-farm-related activities. The percentage of risky movements on a weekday was higher on farms B, D, and E, but on farm C this percentage was lower and more risky movements were made on a day during the weekend. On farm C, it is possible that the working routine was different during the weekend, and some extra violations to the correct working lines were made.
The total number of daily movements towards the farrowing and gestation/insemination unit was higher in the insemination and farrowing week, followed by the weaning week. The farrowing and gestation/insemination unit are places where a much work is needed and farm staff possibly needed to visit these units more than once per day, for example for supervision at farrowing, treatment of suckling piglets, estrus detection and insemination. For the nursery and fattening unit, the number of movements was similar regardless of the week of the BFS. In the absence of specific problems, these units were probably just visited for feeding and routine check of the animals.
The percentage of risky movements towards the farrowing unit and in some farms towards the gestation/insemination unit was higher in the weaning week, but we found no significant differences in the percentage of risky movements towards the nursery and fattening unit. Furthermore, the percentage of risky movements towards the nursery and fattening unit was in general much lower compared to the percentage of risky movements towards the farrowing and the gestation/insemination unit. The nursery and fattening unit were visited less frequently and these visits were probably better organized during the working day, facilitating the implementation of biosecurity principles and as such reducing the risk of making a risky movement.
The number of movements standardized by farm size towards the farrowing and gestation/insemination unit significantly differed according to the week of the BFS, while this was not the case for the number of movements standardized by farm size towards the nursery and fattening unit. In Table 6, showing the number of movements standardized by farm size, values below one can be noticed. The values in the table were obtained because standardization was done to allow a comparison between the farms. In some units, multiple detection points were present in one room. Furthermore, the movements were standardized per 100 sows for movements towards the farrowing and gestation/insemination unit, and all farms had more than 100 sows, leading to these values below one.
To our knowledge, the internal movement monitoring system Biorisk® is the first technology to verify movements of farm staff. There are only a few studies available where this technology has been used. Geurts et al. (2018) studied the association between the number of risky movements and the prevalence of porcine reproductive and respiratory syndrome virus in a farm [26] and Black et al. (2021) studied the association between movements and the number of weaned pigs per sow [27]. In human medicine, similar technologies are already being used e.g. to monitor hand hygiene compliance in hospitals [28]. The internal movement monitoring system allows real-time detection of farm staff. All information is immediately processed on the online platform. However, there are also some limitations to the system. The detection points should be plugged into a socket at all times, and since the location of the detection points is crucial, in some farms extra sockets needed to be installed or extension cables were used. The range of the detection points is 8 meters and goes through walls, so the time filter was needed to ensure that accidental detections were not registered. Furthermore, the system stands or falls by the dedication of the farm staff, as they should wear the beacon at all times. Regardless of these practical limitations, the internal movement monitoring system provided us with new and valuable information on the movements of farm staff in pig farms. The findings also complement the results of previous observational studies on biosecurity in pig farms.