The main welfare issues for piglets are physical interventions: castration, teeth-clipping, and tail-docking. Before addressing these in detail, it is suitable to briefly address whether piglets feel pain. A long-standing,
prevalent theory is that the pain-detecting neuro-anatomy in neonatal piglets is neither completely developed nor fully functioning yet.104 Accordingly, piglets do not feel pain until their neuro-anatomy has developed. Based on this, if physical interventions are to be performed, they should be performed as early as possible, preferably on day-old piglets, as they cannot feel pain and no anaesthetics are required. However, more recent research findings question the validity of this theory and render it outdated. The newest findings, through modern approaches, have proved that piglets do feel pain from the time they are born. According to these, physical interventions cause distress and pain to the piglets, and are detrimental to their welfare,
regardless of when they are performed.105
The first of the main physical interventions relates to piglets’ survival instincts. Piglets are wholly dependent on the sow for their survival: she is their source of heat and food, from the moment of birth until they are
weaned, which varies between eight and nineteen weeks (depending on the sows’ decision).106 As piglets are in competition for teat access with their siblings, they are born with fully erupted corner teeth, also known as ‘needle teeth’.107 The needle teeth pose a risk of causing facial lacerations to their siblings and damaging the sow’s teats. This problem is exacerbated by the breeding of larger litters, which increases the teat-rivalry among the piglets, as the number of teats remains unchanged.108
104
S Held,JJ Cooper,MT Mendl ‘Advances in the Study of Cognition, Behavioural Priorities and Emotions’ in JN Marchant-Forde (ed) The Welfare of Pigs (Springer 2009) 3.2.1.3
105
B Puppe, M-C Meunier-Salaün, W Otten, P Orgeur, ‘The welfare of piglets’ in L Faucitano and AL Schafer (eds.) Welfare of pigs from birth to slaughter (Wageningen Academic Publishers 2008) 6.1
106
D’Eath, Turner (n. 86) 2.4.9, 2.5.5
107
D. Fraser, B.K. Thompson ‘Armed sibling rivalry among suckling piglets’ (1991) 29 Behavioural Ecology and Sociobiology 9
108
Injuries caused by needle teeth are commonly prevented by teeth-clipping. Teeth-clipping is the practice of clipping or grinding of the corner teeth, which causes discomfort, pain, fear and distress109 to the piglet. Teeth- clipping is undesirable for the individual piglet’s welfare, as it is traumatic and causes (prolonged) pain. However, if the collective welfare of a litter as a whole is prioritised over the individual piglets’ welfare, then the situation changes. If all piglets within a litter have their teeth clipped as a preventative measure against harming each other, then the collective welfare increases, as injuries are prevented. Further, teeth-clipping prevents damage to the sow’s teats and saves her from discomfort, pain, and distress – if infected, the wounds can cause severe problems.110 Therefore, before deciding whether to clip or not, the benefits and disadvantages to the welfare of the piglets and the sow should be carefully considered.
Pigs may also be subjected to the practice of tail-docking, and due to legal restraints, docking is likely to be performed on piglets.111 Tail-docking is the severance of the whole or part of the tail as a preventative measure to the vice of tail-biting. Tail-biting commonly occurs when pigs are reared in barren environments, as their innate investigatory behaviour must find an outlet, despite the lack of environmental enrichment.112 Unless anaesthetics
Berg, Lawrence (n. 84); M. Baxter, K.M.D. Rutherford, R.B. D’Eath, G. Arnott, S.P. Turner, P. Sandøe, V.A. Moustsen, F. Thorup, S.A. Edwards, A.B. Lawrence ‘The welfare
implications of large litter size in the domestic pig II: management factors’ (2013) 22 Animal Welfare 219
109
Piglets finds the mere restraint of being picked up and handled distressing, and the teeth clipping procedure have resulted in the specific behaviour of teeth champing and head shaking. Puppe, Meunier-Salaün, Otten, Orgeur (n. 105) 6.1; G.J Noonan, J.S. Rand, J. Priest, J. Ainscow, J.K. Blackshaw; ‘Behavioural observations of piglets undergoing tail docking, teeth clipping and ear notching.’ (1994) 39 Applied Animal Behaviour Science 203; S Held,JJ Cooper,MT Mendl ‘Advances in the Study of Cognition, Behavioural Priorities and Emotions’ in JN Marchant-Forde (ed) The Welfare of Pigs (Springer 2009) 3.2.1.3.; J.S. Rand, G.J. Noonan, J. Priest, J. Ainscow, J.K. Blackshaw ‘Oral administration of a 12% sucrose solution did not decrease behavioural indicators of distress in piglets undergoing tail docking, teeth clipping and ear notching’(2002) 11 Animal Welfare 395
110
Held, Cooper, Mendl (n. 109) 3.2.1.3
111
It is lawful to dock tails before the age of seven days without anaesthetics, and therefore more economic to dock tails on piglets compared to older pigs, see at 3.3.3
112
K. Breuer, M.E.M. Sutcliffe, J.T Mercer, K.A. Rance, N.E. O’Connell, I.A. Sneddon, S.A. Edwards ‘Heritability of clinical tail-biting in pigs and its relation to performance traits.’ (2005) 93 Livestock Production Science 87
are used, tail-docking is painful and distressing for the piglet and may lead to prolonged pain.113
Male piglets are also likely to be castrated, without any pain relief, before the age of seven days.114
There are two main reasons for castrating piglets: to control the aggressive behaviour towards other pigs (due to sexual
development), and to reduce the prevalence of boar taint in meat.115
While a decrease in aggressive behaviour has inherent welfare benefits, the pain inflicted upon the piglets by castration makes it an important animal welfare issue, particularly when the expected diminishing effect on aggressive behaviour does not always occur.116
The scale of castration’s welfare impact is enormous, as every year approximately 100 million piglets are castrated within the EU, and the majority of the castrations are performed without any form of anaesthesia.117 The most common castration method used is a surgical incision in the
scrotum, in order to reveal the testicles, which are subsequently removed by tearing, cutting, or twisting of the spermatic cord.118 Numerous studies show that the piglets suffer considerable pain, especially at the time of cutting (or tearing) of the spermatic cord, and signs of pain have been recorded up to six days after castration, as well as an increase in mortality rates.119
113
Rand, Noonan, Priest, Ainscow, Blackshaw (n. 109); G.J Noonan, J.S. Rand, J. Priest, J. Ainscow, J.K. Blackshaw; ‘Behavioural observations of piglets undergoing tail docking, teeth clipping and ear notching.’ (1994) 39 Applied Animal Behaviour Science 203
114
See at 3.3
115
M. Hansson, N. Lundeheim, G. Nyman, G. Johansson ‘Effect of local anaesthesia and/or analgesia on pain responses induced by piglet castration’ (2011) 53 Acta Veterinarian Scandinavica 34; WJA Boersma, J Meulen, TA and Niewold ‘Balance Between Porcine Disease and Welfare’ in JN Marchant-Forde (ed) The Welfare of Pigs (Springer 2009) 8.5.3
116
EFSA, ‘Welfare aspects of the castration of piglets’ (2004) 91 EFSA Journal 1; Hansson, Lundeheim, Nyman, Johansson (n. 115)
117
EFSA ‘Report on the Analysis of the baseline study on the prevalence of Salmonella in holdings of laying hen flocks of Gallus gallus’ (2007) 97 EFSA Journal; R. Horgan ‘Piglet castration and EU animal welfare legislation’ (2006) 48 Acta Veterinaria Scandinavica 52; N. Jäggin, S. Gerber, U. Schatzmann ‘General anaesthesia, analgesia and pain associated with the castration of newborn piglets’ (2006) 48 Acta Veterinaria Scandinavica 12
118
Jäggin, Gerber, Schatzmann (n. 118)
119
J.J. McGlone, J.M. Hellman ‘Local and general anaesthetic effects on behaviour and performance of two-, and seven-week-old castrated and uncastrated piglets’ (1988) 66 Journal of Animal Science 3049; M. Hay, A. Vulin,S. Genin, P. Sales, A. Prunier
Alternative methods to conventional castration, such as immunocastration, have proved effective in inhibiting sexual development, while crucially reducing boar taint.120 As immunocastration hinders sexual development, it would also have a diminishing impact on aggression levels, which is closely related to the sexual maturity of the pigs. Consequently, there is a huge potential for welfare improvements if immunocastration is promoted over conventional castration methods. Alternatively, research indicates that selective breeding for the purpose of reducing the prevalence of boar taint is possible,121 as technological advances can enable sows to only be
inseminated with carefully gender-determined semen, to avoid male piglets from being born.122
The core welfare needs of the pigs as summarised here, are in line with the holistic definition, which considers the pigs’ physiological and emotional needs, as well as their natural, ethologically motivated needs. In order to have their needs met, pigs should ideally be housed in large, enriched spaces, which enable them to satisfy their locomotion and foraging needs. The pigs’ welfare would further improve if they were kept in stable social groups, with as little mixing with unknown pigs as possible, for the entire duration of their lives, to reduce the prevalence of aggressive behaviour. If
‘Assessment of pain induced by castration in piglets: behavioural and physiological responses over the subsequent 5 days’ (2003) 82 Applied Animal Behaviour Science 201; Hansson, Lundeheim, Nyman, Johansson (n. 115); S. Llamas Moya, L.A. Boyle, B.P Lynch, S Arkins: ‘Effect of surgical castration on the behavioural and acute phase responses of 5 days-old piglets.’ (2008) 111 Applied Animal Behaviour Science 133; Ø.V. Sjaastad, K. Hove, O. Sand ‘Physiology of Domestic Animals’ (2003) Scandinavian Veterinary Press; Jäggin, Gerber, Schatzmann (n. 118)
120
EFSA, ‘Report and Opinion of the Scientific Panel on Animal Health and Welfare on the request from the Commission related to welfare aspects of the castration of piglets.’(2004); Horgan (n. 117); Boersma, Meulen, Niewold (n. 115) 8.5.3; X.Y. Zeng, J.A. Turkstra, R.H. Meloen, X.Y. Liu, F.Q. Chen, W.M. Schaaper, H.B. Oonk, Z. Guo da, D.F. van de Wiel ‘Active immunization against gonadotrophin releasing hormone in Chinese male pigs, effects of dose on antibody titer, hormone levels and sexual development (2002) 70 Animal Reproduction Science 223
121
Rydhmer, Lundheim (n. 93) 13; J. Babol, G. Zamaratskaia, R.K. Juneja, K. Lundström ‘The effect of age on distribution of skatole and indole levels in entire male pigs in four breeds; Yorkshire, Landrace, Hempshire and Duroc (2004) 67 Meat Science 351
122
D. Rath, C.R. Long, J.R. Dobrinsky, G.R. Welch, L.L. Schreier, L.A. Johnson ‘In vitro production of sexed embryos for gender preselection: high-speed sorting of X-chromosome bearing sperm to produce pigs after embryo transfer’ (1999) 77 Journal of Animal Science 3346; S.R. Blecher, R. Howie, S. Li, J Detmar, L.M. Blahut ‘A new approach to
immunological sexing of sperm’ (1999) 52 Theriogenology 1309; Boersma, Meulen, Niewold (n. 115) 8.5.3
any physically invasive procedure need to be performed at any point in the pigs’ lives, anaesthetics and prolonged analgesia should be required and provided.