1. Introduction
Weaning is the most critical and stressful period in the productive life of pigs. The start of the post-weaning phase is characterized by significant social and physiological changes because piglets are separated from the sow, transitioned to solid feed, and placed in new facilities and social groups [
1,
2]. In the context of existing commercial weaning methods, these changes can lead to stress and increase susceptibility to disease, morbidity, mortality, suboptimal growth performance, and costs [
3,
4,
5]. For instance, immunosuppression may increase susceptibility to gastrointestinal diseases, which requires treatment or management to reduce this effect. Consequently, psychosocial stress is a major factor driving gastrointestinal tract pathophysiology and disease susceptibility [
6]. These social and physiological stresses are not easily avoidable but they can be alleviated through proper management and hygiene, thereby enhancing animal welfare and achieving improved productivity and health outcomes [
2,
7].
Until recently, part of the problems derived from stress and poor hygiene and management conditions on farms were mitigated through preventive therapy measures, basically including the use of antimicrobials in feed or water, such as colistin or zinc oxide. However, the increased concern regarding bacterial resistance and social demands [
8] has limited the possibilities of antibiotic prevention. In this regard, the European Food Safety Authority (EFSA) and the European Medicines Agency (EMA) published a set of measures to reduce the need for antimicrobial treatments in animal breeding in the EU and the resulting impacts on antimicrobial resistance [
9].
Currently, there are protocols for assessing animal welfare, such as “Welfare Quality” [
10], as well as studies proposing management measures and factors to consider in order to improve the productivity and health outcomes of farms [
11,
12,
13,
14] or studies evaluating measures to reduce the use of antimicrobials [
5,
15,
16,
17,
18,
19,
20,
21]. In this sense, some of the factors that improve productivity include the number of pigs per pen and the type of feeders [
14], as well as biosecurity elements, such as the implementation of an all-in, all-out protocol or the practice of changing clothes and boots between different groups of pigs to prevent infectious diseases [
12]. However, there is a need for indices and assessment schemes for overall management and hygiene on farms, which include aspects related to biosecurity, production flow, batch dynamics, a reduction in antimicrobial use, and animal welfare from the handling of facilities perspective.
Therefore, the objective of this study was to design a quick scan calculator based on handling and hygiene indices to evaluate the hygienic sanitary conditions and husbandry and management practices during the post-weaning phase. Additionally, to validate this calculator, the scores obtained for the different indices in a set of farms are correlated with their productivity, health, and cost results. Finally, these scores could be used for on-farm self-monitoring and benchmarking purposes. Therefore, if poor management of piglets during weaning compromises their health and performance, it may lead to increased spending on veterinary medicines. It is expected that farms with improved handling and hygiene practices during the post-weaning phase have higher productivity, better health outcomes, and reduced costs compared to farms with suboptimal practices.
4. Discussion
The evaluated farms, with a mean annual productivity of 24.60 PWSY, have lower performance compared to the current Spanish mean (29.38 PWSY) [
26]. Among the farms evaluated, only the most productive one, which achieved 28.72 PWSY, came close to these results. The studied farms were low-tech farms with poorer productive results; therefore, they have much room for improvement, highlighting the need to assess their husbandry, handling, and hygiene practices to improve these results. In this regard, the scores of the farms for the 10 indices of the quick scan handling and hygiene calculator (with a mean overall score of 56.12 out of 100) indicate that although 65.2% of the farms scored above 50 points, it cannot be ruled out that these farms may still have management and hygiene errors and shortcomings. Furthermore, in accordance with Liebig’s Law of the Minimum (also known as Liebig’s barrel), indices with low scores, such as biosecurity, farm stockmen training, post-weaning room temperature, or ventilation management, could act as limiting factors in ensuring proper handling and hygiene, which are essential for achieving good performance and health during post-weaning in the studied farms.
When evaluating these indices, the pre-weaning handling, with a mean score of 6.87 out of 10, is one of the indices with a better overall score. Thus, proper handling during lactation is crucial for the successful start of the post-weaning phase to ensure proper colostrum intake in the first few hours after farrowing [
27,
28,
29]. Early access to water and feed enables lactating piglets to start consuming these as early as possible. It is important to offer feed frequently (at least twice a day) in a clean feeder to stimulate solid feed intake from the beginning of their lives [
2]. However, 21.7% of the farms obtained a score of <5 points in this index, compromising the good start of weaning.
The mean number of post-weaning rooms per farm was 10.52. Nevertheless, 25% of the farms had an average number of post-weaning rooms below seven. This poses a challenge for implementing the all-in all-out veterinary hygiene principle for post-weaning batch management. Specifically, in cases where piglet production occurs in weekly batches, adhering to this hygiene principle requires 7 weeks of occupation with pigs [
7] and 8 weeks of rotation to have time for cleaning and disinfection. Consequently, batch management had a mean score of 5.98 points, including crucial aspects, such as attention to smaller piglets or segregation by weight in pens to reduce hierarchical competition, which leads to significant differences in water and feed consumption and even pathology morbidity and mortality after weaning [
30]. Segregating piglets by body weight is a common management strategy to reduce weight variability and facilitate pigs’ handling [
31]. Therefore, in this study, segregation by weight has been considered as a best practice. However, the crucial factor lies in having a clear segregation criterion to minimize growth disparities during the post-weaning period. This could also be extended to piglet segregation based on litter or gender. López-Vergé et al. [
32] pointed out that despite initial efforts to segregate piglets by weight at the beginning of the post-weaning phase, the coefficient of variation in piglet weight tends to rise, reaching levels comparable to piglets segregated by litter, due to an early socialization strategy.
Overall, the biosecurity mean scores were low (5.11 points), with 17.4% of the farms having values well below five. This low score is due to the lack of basic measures such as footbaths, isolation or sickbay facilities, proper cleaning and disinfection, and proximity to other farms or roads. These hygiene measures are essential to prevent the entry and spread of diseases on the farm. Currently, there are good internal and external biosecurity evaluation systems described by various authors [
12,
33,
34,
35], who demonstrated the importance of farm biosecurity measures in reducing antimicrobial consumption and improving production outcomes.
Regarding water management, 60.9% of the farms obtained a mean score below five points due to poor water quality, lack of chlorination or purification treatment, and the absence of good management practices. Drinking water must be clean, fresh, colorless, and free from microorganisms [
36], and its good quality is indispensable during post-weaning [
7]. In the feed management index, 30.4% of the farms score less than five points due to management errors, such as the lack of feeders with water or mash feed for piglets at early weaning, as well as the absence of rehydration measures during the first days. Implementing these management measures promotes early water and feed consumption, resulting in a better start and intestinal health of the piglet [
37]. Additionally, a decrease in feed intake during the first week after weaning is strongly correlated with the risk of disease occurrence during this phase [
38,
39]. Furthermore, Raasch et al. [
19] indicated that improving the quality or composition of feed or water is the most commonly implemented intervention on farms as an alternative to reducing antimicrobial use and improving consumption. In this sense, the design of the feeder also influences feeding behavior habits [
40]; thus, O’Connell et al. [
41] indicated that the dry multi-space feeder could be the most optimal feeder for weaned piglets in terms of performance and animal welfare.
The training of farm stockmen also obtained a low mean score (4.93 out of 10). However, this index is crucial for the proper functioning of any farm because trained and skilled stockmen know good animal handling and consider all possible negative and positive influencing factors [
42]. Hence, it is important to provide clear instructions to workers, including critical points to check and a daily routine that facilitates their work [
37]. Magallón et al. [
43] emphasize the importance and effect of theoretical and practical training of farm workers on short- or medium-term productivity and indicate that by means of training, it is possible to increase the number of weaned piglets per litter by almost one in just one year. In addition, Spoolder and Ruis [
44] pointed out some of the most important attributes a professional stockman needs: a solid technical understanding of what weaned piglets need; a sharp ability to interpret the signals animals give regarding their health and welfare status; and the ability to take action based on that information. Furthermore, proficiency in skills, such as understanding post-weaning targets and associating animal performance with their handling and health, is crucial, as they directly affect farm profitability.
The scores for the temperature and ventilation indices were also low, with only 30.4% and 39.1% of farms meeting the temperature and ventilation criteria, respectively. However, both environmental indices are crucial for maintaining productivity and reducing piglet stress and respiratory diseases during weaning [
45,
46]. Thus, post-weaning rooms should be heated to 28–30 °C for piglet entry, avoiding daily fluctuations and gradually reducing the temperature by 1–2 °C each week until reaching 22 °C at the end of the phase [
7]. Additionally, room temperature also depends on the flooring and stocking density and recommends plastic slatted floors, which have lower heat loss compared to concrete floors [
47]. On the other hand, in cold weather, it is important not to compromise ventilation in an attempt to maintain temperature. Always ensure a minimum ventilation flow while avoiding exposing the animals to cold air, and maintain a maximum air velocity of 0.15 m/s at the piglet height [
7,
48]. The type of flooring also affects air quality, increasing ammonia concentration with partial slats compared to total slatted pens [
49]. In general, the goal of ventilation is to renew the volume of air in the weaning rooms, prevent respiratory pathologies, regulate temperature, eliminate harmful gases, and ensure the necessary supply of oxygen [
7]. In this regard, there are many studies suggesting strategies and better facilities to improve the air quality of farms [
7,
47,
49,
50,
51]. However, caution must be taken with newly weaned piglets, as they are highly susceptible to low temperatures and high air speeds [
47].
Additionally, the Pearson correlations validate the usefulness of the quick scan handling and hygiene calculator, as the overall score of the calculator correlates significantly (
p < 0.05) with the main productivity parameters of piglets during the post-weaning phase (FCR, mortality rate, and production cost). Thus, farms that achieved a higher score in the overall evaluation of management and hygiene indices had lower production costs and lower mortalities during the post-weaning phase. These results are in agreement with other authors [
52,
53] who linked the influence of different management factors to the productivity parameters of farms. Additionally, there is also a negative correlation with the medication costs per piglet during the post-weaning phase (
p < 0.05), indicating that farms with higher handling scores have lower medication consumption. Therefore, the best way to reduce the consumption of antimicrobials is to guarantee good handling and hygiene to reduce the occurrence of diseases [
17].
Furthermore, indices such as biosecurity, batch management, and pre-weaning handling correlate with post-weaning productivity and medication expenses. Thus, Postma et al. [
35] evaluated the relationship between biosecurity, productive parameters, and antimicrobial use in four EU countries, concluding that good management practices and biosecurity measures are factors that impact antimicrobial consumption and productivity parameters.
On the other hand, the indices of floor type and density, ventilation and temperature of the post-weaning rooms, and water management do not show significant correlations with the studied productivity and health parameters [
47], indicating that these management and hygiene indices influence the mortality rate and the productivity during post-weaning. Additionally, some authors propose other management measures or factors [
11,
13,
14], such as the age of the building, to evaluate the air quality and its bacterial load or suggest fewer piglets per pen, which could be included in future versions of this quick scan calculator.
When comparing farms according to the quartiles of annual productivity and cost of medications per piglet, it is observed that farms with higher annual productivity also achieve better productivity and health outcomes during the post-weaning phase of the piglets. These results align with a study conducted by Pierozan et al. [
54], where they indicate a parallelism between productivity increase and the improvement of management practices, biosecurity measures, and handling techniques. Although PWSY is linked to the pre-weaning phase, annual productivity is the parameter that best reflects farm efficiency [
55], so it was considered relevant to compare farms according to their level of efficiency based on this parameter. Hence, these results demonstrated that farms achieving good results during weaning also perform well in the post-weaning phase, with lower post-weaning mortality, reduced medication expenses, and lower piglet cost.
On the other hand, the group of farms with higher costs of medication per piglet had poorer productivity and health parameters. Although the use of antimicrobials in farms is currently being reduced, the relationship between the use of antimicrobial drugs to improve farm production has been recognized for decades [
56,
57,
58], especially in swine production [
59,
60,
61]. Therefore, efforts should continue to be made for their control worldwide, as a recent study confirms an association between the use of antimicrobials on farms and their resistance in humans [
62]. Additionally, the results obtained are in accordance with Diana et al. [
5], who indicate that improvement in management practices can reduce antimicrobial use without significantly affecting the productivity and health outcomes of the farms.
Finally, the possible margin of error in the design of this quick scan calculator would be compensated by the high number of indices evaluated (10), their low contribution to the total score (maximum of 10 out 100 per index), and how evenly that contribution is distributed within different management factors (from four to eight per index). Additionally, this quick scan calculator does not require animal-based measures, so it is quick to use and avoids animal manipulations. Overall, this quick scan handling and hygiene calculator has been designed to assess routine practices within a farm. However, its functionality may be constrained under conditions of severe disease. For example, in the event of a disease outbreak, both production and health parameters would be profoundly affected, even with appropriate piglet and facility management. Additionally, some indices are overly simplistic: the health program index only considers two PRRS status situations; the assessment of biosecurity does not differentiate between internal and external biosecurity; and the evaluation of water quality does not take into account the results of the periodic analyses (it only considers the fact of analyzing water as a first step for its hygiene). To address these issues, a more comprehensive version of the calculator could be developed; however, this would necessitate a significantly larger questionnaire, compromising its aim of being a quick and user-friendly tool for farmers and technicians. For a more complete evaluation of some indices, there are other questionnaires; for example, Pitkin et al. [
63] for PRRS, Pritchard et al. [
64] for biosecurity, Edwards and Crabb [
65] for water management, or the wean to finish guidelines of PIC [
66] for ventilation and other issues.