Effect of Age on Piglets' Behavioral and Physiological Responses to Tail Docking and Ear Notching

December 31, 2008 — 

Neonatal piglets are often subject to potentially painful processing procedures such as tail docking and ear notching during the first few days after birth. However, these procedures may influence the development of suckling behavior and passive transfer of immunoglobulins, especially if done within the first day postpartum. The objective of this experiment was to compare the effects of processing piglets during the first 24 h versus at 3 d of age on suckling and pain-related behavior, the passive transfer of immunoglobulins, and growth. Six piglets per litter from 20 litters (n=120 piglets) were used in a 3 x 2 complete block design. Piglets were weighed at birth and assigned to 1 of 3 treatments (balanced by birth weight): control (C; unmanipulated), sham processed (S; manually manipulated) and processed (P; tail docked and ear notched) at 1 of 2 ages (1 or 3 d-of-age). Vocalizations were recorded during the procedures, and piglets were observed after the procedures for pain-related behavior. Suckling behavior was observed for 6 h on each of d 1 to 4. Colostrum samples were collected after the birth of all piglets (prior to first suck), and blood samples were collected on d 5 to examine levels of immunoglobulins (IgA and IgG) and insulin-like growth factor-I (IGF-I). Body weights were measured at birth and on d 5 and 14. During the procedures, P piglets, regardless of age, vocalized at a higher frequency (P < 0.001) and produced more high frequency calls (P = 0.016) than S piglets. All piglets on d 1 produced more high frequency calls than all piglets on d 3 (P = 0.047). Immediately after the procedures, S and P piglets spent less time lying and more time standing than C piglets (P < 0.001), whereas P piglets jammed their tail between their legs more than S or C piglets (P < 0.001). Lying, standing and tail posture were not influenced by age, nor were there age by treatment interactions. Piglets on d 1 trembled more than piglets on d 3 (P < 0.001), and this tended to be exacerbated by processing (P = 0.076). There was no effect of treatment or age of treatment on suckling behavior. P piglets had lower IgG serum concentrations than S and C piglets (P = 0.029), although there was no interaction between treatment and age of treatment (P = 0.67). While tail docking and ear notching do appear to result in short-term pain and modulated immune status, processing on d 1 appears neither better nor worse than processing on d 3.

Torrey S, Devillers N, Lessard M, Farmer C, Widowski T, Effect of Age on Piglets' Behavioral and Physiological Responses to Tail Docking and Ear Notching, J Anim Sci. 2008 Dec 19. [Epub ahead of print]