The welfare of non-human primates used in scientific research must be safeguarded to promote scientific validity and for ethical reasons. Welfare can be improved by the refinement of practice, particularly if these refinements are applied to every aspect of the life of an animal used in the laboratory, from birth to death with the aim of both minimising harm and maximising well-being. Many refinement methods have been described in nationally and internationally accepted guidelines on laboratory practice, but awareness of these guidelines is not universal. In Part I of this review, we examine the influence of humans on non-human primates and summarise and evaluate methods of refinement that are or could be used to reduce suffering and improve welfare. In particular we focus on staff selection, education and training, human–animal bonds, staff communication, and training primates. In Parts II and III, refinements of housing, husbandry and experimental procedures are reviewed.

In order to safeguard the welfare of laboratory-housed non-human primates, refinement techniques should be applied to every aspect of the life of animals used in the laboratory, from birth to death, with the aim of both minimising harm and maximising well-being. In this second part of a three-part review we summarise published information on housing and husbandry practices, and describe ways to minimise contingent inhumanity associated with the use of primates in laboratories and their breeding and supply (where inhumanity is defined as the infliction of distress). We also discuss methods by which the welfare of these animals can be maximised on a day-to-day basis. The principles of enrichment, aspects of the housing environment, social and physical enrichment and acquisition are discussed. Refinement of the influence of humans and experimental procedures are discussed in Parts I and III of this review, respectively.

There is an ethical and scientific need to minimise the harm experienced by animals used in scientific procedures and to maximise their well-being. Welfare can be improved by the refinement of practice, particularly if these refinements are applied to every aspect of the life of an animal used in the laboratory, from birth to death. Primates are considered likely to have a greater capacity for suffering than other sentient species and therefore refinement of their use is particularly important. The refinement of the human impact on laboratory-housed primates and of housing and husbandry practices are dealt with in parts I and II of this three-part review. In part III, methods of refinement that can be applied specifically to the use of primates in procedures, are summarised and discussed, together with a description of some current practices, and the scientific evidence that suggests that they should no longer be used. Methods of refinement of identification, capture and restraint, sampling, administration of substances, humane endpoints, and euthanasia are included. If these methods are used, taking into account species-specific differences and needs, it is concluded that harm can be minimised and primate welfare improved.

In recent years there has been an increased interest in studies related to the welfare of avian species commonly kept as companion animals, specifically those in the order Psittaciformes, commonly referred to as ‘parrots’. During this time the biology and behaviour of wild parrots has also become better understood, aiding the assessment of welfare in captive environments. The impact of the pet trade on wild parrot populations has also become clear. This order now has more globally threatened species than almost any other major group of birds. Many significant aspects of parrot behaviour in the wild, such as flocking, social interaction with conspecifics, foraging on a variety of foods and flight, are denied to varying degrees to parrots kept as companion animals. Captive parrots show high levels of stereotypy, suggesting poor welfare. Welfare may be improved by appropriate environmental enrichment and changes in the social environment of captive parrots kept as companion animals; however, such changes require that caretakers have sufficient knowledge, resources and motivation to accommodate such conditions. The concept of companion animal suitability is an important consideration when developing regulations or policy aimed at improving the welfare of animals kept as companions. Although individual exceptions exist and the level of suitability may vary depending on species, in general, their presence in the pet trade has resulted in serious animal welfare and conservation challenges for parrots, indicating that these animals may be unsuitable as human companions.

Male piglets are castrated primarily to prevent the unpleasant odours and flavours of entire male pig meat (boar-taint). Although castration can be legally performed without analgesia in the first seven days of life, available evidence shows that castration at any age is painful and may have a detrimental influence on health. Few anaesthetics or analgesics are licensed for use in piglets. The known methods for general and epidural anaesthesia cannot be run at the farm level for practical and/or legal reasons. Use of the local anaesthetic lidocaine is easy and allows the pain resulting from castration to be alleviated. Local destruction of testicular tissue by intra-testicular injection of chemical compounds (salts and acids) is an alternative to surgical castration but needs further investigation regarding welfare improvement and boar taint reduction. Immunocastration, by which castration is achieved using active immunisation (anti–GnRH immunisation) is an efficient alternative to surgical castration; however, there are no licensed vaccines in the EU and the consequences, in terms of pig welfare as well as its acceptability among EU consumers, need further evaluation.

Two experiments were carried out to determine the effect of different teeth resection methods on skin temperature, concentrations of the acute phase proteins C-reactive protein (CRP) and serum amyloid A (SAA), and cortisol in piglets. In Experiment 1, piglets from 60 litters were assigned to three treatments where the ‘needle’ teeth were clipped (CLIP), ground (GRIND) or left intact (INT) within 12 h of birth; skin temperature was measured immediately afterwards. Fourteen pigs were selected in each treatment for blood sampling at 1 day and 29 days-of-age for the determination of concentrations of CRP, SAA and cortisol. In Experiment 2, a 2 × 2 factorial design was used to determine the effect of teeth clipping and time spent out of the farrowing crate post-clipping on skin temperature. Piglets from 60 litters had their teeth clipped (CLIP) or left intact (INT) and were returned to the farrowing crate immediately or after 1 min. Skin temperature was measured after piglets were returned to the farrowing crate and after 10 min. In Experiment 1, CLIP and GRIND piglets had significantly lower skin temperatures than INT piglets; skin temperature was also significantly reduced in CLIP piglets in Experiment 2. Skin temperature did not differ between time-out groups. Plasma levels of CRP and SAA did not differ between treatments on day 1; however, concentrations of both proteins were significantly higher on day 29. CLIP pigs had significantly higher concentrations of CRP in comparison with GRIND pigs on day 29. Stress caused by teeth resection provoked a transient reduction in skin temperature. Furthermore, both resection methods caused infection and/or inflammation, but to a similar degree as that caused by leaving the teeth intact. These results indicate that the welfare of piglets is better in the short term if their teeth are left intact; however, if teeth resection is necessary grinding can be recommended in preference to clipping.

Meat from low-volume farm animals such as farmed deer and wild boar is currently widely available to the consumer within the UK. Despite a rapid growth in production of these species there is a paucity of research that focuses on their welfare. This paper reviews the current literature and legislation relating to the transport and slaughter of farmed deer, wild boar, ostriches, buffalo and bison in order to identify priorities for future research. Research on low-volume farm animals has focused on red deer and their welfare is safeguarded with comprehensive legislation and guidelines. Studies have indicated the importance of appropriately designed facilities and sympathetic handling of red deer to ensure humane slaughter with minimal stress. However, the impact of transport and slaughter on the welfare of other deer species has not been recorded and this should be recognised. Much research has been conducted on the welfare of ostriches during transport and at slaughter. However, many of the results are discordant and research is required to clarify, in particular, posture during transport and stunning methods. Research on the welfare of wild boar, buffalo and bison is scarce. Best practice for both transport and slaughter of these species needs further research and clarification within legislation. For the low-volume species discussed in this review, priorities for further research include (1) appropriate methods of handling to minimise stress during transport and slaughter; (2) identification/clarification of appropriate slaughter methods and (3) training of transport and abattoir personnel in handling and slaughter methods.

To define suitable holding conditions for fish used in experimental studies on food consumption and growth, the effect of cover on growth at two ration levels was quantified for immature individuals of two common, freshwater species: the threespine stickleback (Gasterosteus aculeatus: Gasterosteidae) and the European minnow (Phoxinus phoxinus: Cyprinidae). In the European minnow, the presence of cover significantly increased growth rates and also the rate of food consumption at ad libitum rations; however, cover had no significant effect on the growth of the threespine stickleback. In both species, fish fed ad libitum rations had higher growth rates than fish fed 4% of body weight per day. This study illustrates the need for species specific holding conditions and illustrates an approach to welfare using measurements of traits closely related to fitness.