Use of space and behavior of weaned piglets kept in enriched two-level housing system

Implementation of a Pig Toilet in a Nursery Pen with a Straw-Littered Lying Area

Simple Summary

Generally, pigs are known to be very clean and intelligent animals. The present study tested whether it is possible to train nursery pigs to defaecate and urinate in a pig toilet while keeping a straw-bedded lying area clean. The pig toilet was separated into a defaecation area and a urination area. An automatic rewarding system installed in the urination area and pig faeces placed in the corners of the defaecation area were used to help the pigs to identify the elimination area. By means of direct observation and video analysis, all eliminations within the experimental pen were analysed. Altogether, the pig toilet was very well accepted by the pigs, but a spatial separation of faeces and urine was not achieved. The lying area was kept clean, so that keeping pigs on straw in combination with a pig toilet would be quite conceivable in the future to enable a more animal-friendly life.

Abstract

In this study, a pig toilet was installed on an organic pig farm, which enabled pigs to use a lying area littered with straw and keep it clean. The pig toilet was separated into a defaecation area and a urination area and nursery pigs were trained to use the urination area by means of a rewarding system. A total of 24 piglets were weaned at 6–7 weeks of age and housed in the experimental system for four-week periods. Per trial, a group of four pigs was formed, and videos were recorded on two days per week (08:00 to 18:00). Direct observation was carried out in the first and last week of each trial. In total, 1500 eliminations were video-analysed. An individual pig had an average of 7.1 ± 1.4 defaecations and 4.8 ± 0.8 urinations per day. In total, 96.4% of all urinations and 97.4% of all defaecations were performed in the pig toilet. However, most urinations took place in the defaecation area as well (90.4%). Even if the training to spatially separate defecation and urination behaviour was not successful, we showed that a pig toilet offers the possibility to create littered lying areas, possibly increasing animal welfare.

Effect of pens with an elevated platform on space utilization, skin lesions and growth performance in nursery pigs

Environmental enrichment, adequate space and the ability to separate a living area into suitable functional areas are key elements for pig welfare. In this study, a two-level pen for nursery pigs was explored with the aim of analysing the use of space and the impact on pig behaviour, health and performance. Therefore, per batch, three experimental groups in pens with elevated platforms (two-level pens) and one control group in a standard pen were formed after weaning at the age of 4 weeks. Thereafter, groups were studied for a period of 6 weeks. In a total of eight batches (n = 882 pigs), the occurrence of skin lesions was determined per individual using a lesion score, and in seven batches (n = 761 pigs) individual daily weight gain was analysed. In five batches (n = 450 pigs), the individual use of space and the behaviour of pigs were investigated by direct observation (4 h per day on 2 days in weeks 1, 3 and 6 of the housing period, respectively). Results revealed that 98.9% of pigs (n = 445) were observed on the elevated platform at least once. The probability that an individual pig used the platform was significantly higher than 0.95 (P < 0.0001, confidence interval = 0.977, 1). The use of the platform was not affected by sex (odds ratio (OR) = 1.013, P = 0.937). However, the probability of observing an individual on the elevated platform increased with increasing BW during the experimental period (OR = 1.043, P < 0.0001). The presence of a platform decreased the probability of seeing a pig fighting (P = 0.014) and increased the probability of observing locomotor behaviour as opposed to lying (P < 0.0001). In two-level pens, pigs sustained fewer skin injuries than in standard pens (day 41: OR = 0.731, P < 0.0001). Over 41 days of experiment, pigs in two-level pens had higher daily weight gains than animals in standard pens (416 versus 393 g/day, P = 0.006). We conclude that usable space for nursery pigs can be effectively extended by introducing elevated platforms into the pigs' pen. Furthermore, pigs may benefit from two-level systems by establishing spaces for activity as well as for retreat from other pen mates, thereby reducing aggressive behaviour and social stress. The installation of two-level pens is therefore encouraged, if they are intended to provide more space than legally stipulated.

Soiling of Pig Pens: A Review of Eliminative Behaviour

Simple Summary

The soiling of pig pens has important negative consequences in terms of animal welfare, health, workload, and environmental emissions of pig farming. The aim of this review is to present the state-of-the-art regarding pigs’ normal eliminatory behaviour (i.e., defaecation and urination) and pen soiling, aimed here at solving pen-soiling problems in existing systems, and in a following publication aimed at the design of a more sustainable pig-farming system. To this end, we summarize a large body of literature on pen soiling and pigs’ eliminative behaviour in different farming systems. We propose a “disease framework” interpretation of pen soiling, to help identify its causes, underlying mechanisms, and solutions.

Abstract

This is a comprehensive review on the pigs’ normal eliminatory behaviour (i.e., defaecation and urination) and pen soiling. This review is aimed primarily at solving issues with pen soiling in current systems, and ultimately at the future design of a well-functioning pig toilet, which we intend to elaborate on in a subsequent publication. In this paper, first, normal elimination is described in relation to what is known about its phylogeny, ontogeny, causation, and function, i.e., according to Tinbergen’s four why questions concerning animal behaviour. Then, pen soiling is described as if it were a medical disorder, highlighting its importance, aetiology, symptoms, diagnosis, pathogenesis, treatment, and prevention. Due to its negative consequences in terms of animal welfare, health, workload, and environmental emissions, possible methods to address pen soiling in current systems are described. Probably, pigs do not choose a specific place to eliminate but rather choose the most comfortable place for resting, and avoid eliminating there. We identified four main strategies to reduce pen soiling: (1) reducing the suitability of the designated elimination area to be used for other functions, especially resting or thermoregulation; (2) improving the suitability of other functional areas in the pen to be used for their specific function, such as resting and activity; (3) reducing the suitability of other functional areas to be used for elimination; and (4) improving the suitability of the elimination area for elimination. These prevention strategies and the encompassing disease framework provide a structured approach to deal with pen soiling in existing systems and to support the future design, development, and implementation of a well-functioning pig toilet that can help to achieve some of the main goals of modern pig production, namely reducing environmental emissions as well as substantially improving pig welfare.