Advances in Pig Welfare

Irene Camerlink, Irene Camerlink

• Publisher: Woodhead Publishing
• Year: 2017
• ISBN:
  9780081011195
• Topic: Tecnologia e ingegneria
• Subtopic: Allevamento di animali

Advances in Pig Welfare analyzes current topical issues in the key areas of pig welfare assessment and improvement. With coverage of both recent developments and reviews of historical welfare issues, the volume provides a comprehensive survey of the field.

The book is divided into two sections. Part One opens with an overview of main welfare challenges in commercial pig production systems and then reviews pig welfare hot spots from birth to slaughter. Part Two highlights emerging topics in pig welfare, such as pain and health assessment, early socialization and environmental enrichment, pig-human interactions, breeding for welfare, positive pig welfare and pigs as laboratory animals.

This book is an essential part of the wider ranging series Advances in Farm Animal Welfare, with coverage of cattle, sheep, pigs and poultry.

With its expert editor and international team of contributors, Advances in Pig Welfare is a key reference tool for welfare research scientists and students, veterinarians involved in welfare assessment, and indeed anyone with a professional interest in the welfare of pig.

• Provides in-depth reviews of emerging topics, research, and applications in pig welfare
• Analyzes on-farm assessment of pig welfare, an extremely important marker for the monitoring of real welfare impacts of any changes in husbandry systems
• Edited by a leader in the field of pig welfare, with contributing experts from veterinary science, welfare academia, and practitioners in industry

Part I

Pig Welfare Hot Spots

Outline

Chapter 1 Overview of commercial pig production systems and their main welfare challenges

2 Sow welfare in the farrowing crate and alternatives

Chapter 3 Piglet mortality and morbidity: Inevitable or unacceptable?

4 Lifetime consequences of the early physical and social environment of piglets

Chapter 5 Tail biting

Chapter 6 Chains as proper enrichment for intensively-farmed pigs?

7 Mitigating hunger in pregnant sows

8 Aggression in group housed sows and fattening pigs

9 Transport of pigs to slaughter and associated handling

10 Slaughter of pigs

Chapter 1

Overview of commercial pig production systems and their main welfare challenges

Lene Juul Pedersen, Aarhus University, Tjele, Denmark

Abstract

The chapter starts with an overview of common pig production systems across the life cycle of the pig. Thereafter, the welfare legislation setting minimum welfare standards for the production in EU is described. The bulk of the chapter then documents that the majority of the welfare problems still remaining are related to close confinement or lack of space, lack of enrichment and bulky feed, early weaning and breeding for intensive production traits such as high prolificacy of sows. To make progress, there is a strong need for an open-minded and sustained collaboration between animal scientists, environmental scientists, companies that develop equipment for the pig industry as well as stakeholders from both the industry and animal welfare organisations. Important focus areas are mentioned such as a continued development of non-confinement housing systems for sows, development of feed stuff with bulkiness, balancing breeding goals with productivity and welfare, and development of slurry systems that can handle larger amounts of organic materials.

Keywords

Pig production; sow housing; animal welfare; EU welfare legislation; confinement; enrichment; space; review

1.1 Introduction

Since the 1960s, the commercial pig production in industrialised developed countries has undertaken a dramatic change, from small family-run farms to larger industrialised production units with a private owner and several/many employees. These changes have led to a shift from extensive housing systems with a low degree of confinement and high labour input, to economically efficient units with low labour input, low space allowance, a high degree of confinement, and use of slatted floor systems with little or none environmental enrichment. In addition, the management has changed towards the use of automated feeding and climate control systems, less surveillance of individuals, and use of early weaning and artificial insemination methodologies.

Along with these changes, there has been an arising awareness of animal welfare issues related to the use of industrialised production methods amongst consumers, policy makers and retailers. Therefore, today’s pig production in the EU, which is responsible for approximately 25% of the world’s pig production in 2014 (FAO), is to some extent controlled by welfare legislation setting down minimum standards for acceptable welfare. Similar welfare regulations are now emerging in other pig-producing countries, such as the United States, Canada and Australia.

Despite the welfare legislation, the pig industry still faces major welfare challenges. These are not easily solved under economically tight production conditions, and an increasing demand on the industry to reduce the environmental impact of the pig production. To be able to improve pig welfare under these conditions, there is an urgent need for an open-minded and obligating collaboration between animal scientists, environmental scientists, companies that develop equipment for the pig industry, as well as stakeholders from both the industry and animal welfare organisation. The aim of this chapter is to: (1) give an overview of productions systems used in the industrialised pig production of bulk meat; (2) summarise how housing and management within the EU countries are affected by the EU Directives; and (3) describe the causes for major welfare problems still remaining and possible ways forward to solve them.

1.2 Production cycle of pigs

Breeding of female pigs is organised into a three-step system consisting of breeding herds, multiplier herds, and production herds. In the breeding herds, purebred sows and boars are selected and bred according to a specific selection criteria defined by the company’s strategy. The purebred sows are not used for production of rearing pigs but female offspring are used in multiplier herds where crossbreeds are produced and sold to production herds where the rearing pigs are produced. Our discussion here is only concerned with the rearing of sows and pigs in production herds.

To understand the different welfare challenges in the production herds, a brief introduction to the production cycle of pigs are given below. The cycle divides the pig production into stages, each representing different housing systems, different welfare regulation and welfare problems. The different units may of course not be representative for pig production throughout the world, but cover the majority of the somewhat standardised bulk pig production.

1.2.1 The mating unit

Conception of a production pig usually takes place by artificial insemination of a production sow. Prior to insemination, sows are placed in a specific mating unit after weaning of the previous litter. Usually sows come into oestrus within 4–6 days after weaning. Oestrus lasts 2–3 days, and during this period sows are artificially inseminated 2–3 times while given contact (physically and/or visually) with a mature boar. The fertilisation takes place within 24 hours after insemination, while the attachment of the embryo to the uterus does not occur until 7–14 days after. During this period, the survival and attachment of the embryos are sensitive to imbalances. Therefore, any disturbances during this period may result in a low litter size or in lack of conception, resulting in the sow returning to oestrus after 3 weeks. Sows are typically housed in the mating unit from the time of weaning of the previous litter until 4 weeks after, or until the last insemination has taken place (when the oestrus symptoms have ceased). Sows are kept in the mating unit until 4 weeks after weaning to confirm that they are pregnant. This can easily be done in the mating unit using boar stimulation, while observing if sows return to oestrus 21 days after insemination. In addition, keeping sows in the mating unit until 4 weeks after insemination will ensure that sows are not exposed to disturbances caused by a change in environment during the sensitive period of attachment of the embryos to the uterus.

In herds that supply their own production sows, female pigs are selected at a young age to replace culled production sows. The selected female pigs will be moved at puberty to the mating unit to be inseminated, usually in their second or third oestrus. Other herds may purchase crossbreed female pigs from the multiplier herds usually before puberty. When pregnant, the young female pigs are termed gilts until they give birth to their first litter. From that time, they are called sows. A sow is usually culled after 4–6 litters; some will only produce one litter while a few will get more (typically not more than 8–10 litters). When culled they will be replaced by new gilts.

1.2.2 The gestation unit

After the mating unit, the sows are moved to the so-called gestation unit where they ideally stay until 5–7 days prior to parturition.

1.2.3 The farrowing unit

Some days before birth is expected, farrowing sows are moved to the farrowing unit. In this unit sows give birth to a litter of 10–25 piglets. They stay in the unit during farrowing and until artificial weaning of the litter, which typically takes place between 2 and 5 weeks after farrowing. The time of weaning may be controlled by welfare regulation (see later in the chapter). As soon as the piglets are weaned by moving them away from the sow, she will return to the mating unit to start a new reproductive cycle. Otherwise, she may at this point be culled due to age, disease, reproductive problems or poor maternal performance. In countries using high prolific sow lines, the litters may be too large for the mother sow to nurse by herself. This has led to the use of so-called nurse sows that first give birth and nurse their own offspring for 7–21 days and then are given 2–7-day-old surplus piglets from another sow to nurse until weaned. This system is routinely used, for example in Denmark, where the average litter size has reached more than 17 piglets due to intensive selection for large litter size. These nurse sows will stay for a prolonged period in the farrowing unit.

1.2.4 The weaner unit

At weaning, the piglets will typically be moved to a weaner unit and are now called weaners. In the weaner unit, the climate and feed system needs to be customised to meet the physical and nutritional requirements of early weaned pigs.

1.2.5 The rearing unit

When weaners are around 25–30 kg they are moved to the rearing unit where they stay until slaughter. They are now called rearing pigs (term used in this chapter) or fattening pigs, finishers or slaughter pigs. The weight at slaughter is depending on the production method and condition, but will typically vary between 80 and 120 kg. At slaughter the pigs are around 5–8 months old. The life of production sows and weaner/rearing pigs is illustrated in Fig. 1.1.

Figure 1.1 Schematic illustration of life of production sows and rearing pigs.

1.3 Housing systems and EU welfare regulation

As described above, each production stage typically takes place either in different units of a farm, or on another farm specialised in the specific production period (e.g., sow herds or pig rearing herds). In both cases, the housing and management are customised to fit the specific events taking place in each stage. In the following material we will focus on describing some examples of the most commonly used housing systems seen on larger industrialised farms producing the majority of the pig meat in Europe for the bulk market. Similar systems are also found in other parts of the world where industrialised pig production takes place, such as China, North America and Brazil. In the EU countries, welfare legislation set minimum standards for the production of pigs, with specific regulations for each stage in the production life. In 1991, the Council Directive 91/630/EEC laying down minimum standards for the protection of pigs was adopted. The Directive contains minimum standards for pigs, minimum space allowances for weaners, breeding sows and rearing pigs, and general requirements for housing, equipment, surveillance, feed and water are described. In an appendix, more specific requirements for each category of pigs (boars, sows and gilt, suckling piglets, wean...