Monthly Archives: October 2017

Docking piglet tails: How much does it hurt and for how long?

Docking piglet tails: How much does it hurt and for how long?

By Pierpaolo Di Giminiani, Abozar Nasirahmadi, Emma M. Malcolm, Matthew C. Leach, Sandra A. Edwards. 2017. Physiology & Behavior 182: 69-76.


• Short and long-term behavioural changes due to tail docking in pigs are described.
• Vocalisations suggested the procedure to be painful for piglets.
• The behaviour sampling adopted detected no changes up to 2 days post-tail docking.
• Long-term effects of tail injury on mechanical nociceptive thresholds were absent.


Tail docking in pigs has the potential for evoking short- as well as long-term physiological and behavioural changes indicative of pain. Nonetheless, the existing scientific literature has thus far provided somewhat inconsistent data on the intensity and the duration of pain based on varying assessment methodologies and different post-procedural observation times. In this report we describe three response stages (immediate, short- and long-term) through the application of vocalisation, behavioural and nociceptive assessments in order to identify changes indicative of potential pain experienced by the piglets. Furthermore, we evaluated the following procedural differences: (1) cautery vs. non-cautery docking; (2) length of tail removal. Sound parameters showed a significantly greater call energy and intensity exhibited by docked vs. sham-docked piglets (P < 0.05). Observations of general activity of the animals in a test situation failed to detect a difference among treatments (P > 0.05) up to 48 h post-tail docking. Similarly, no difference in mechanical nociceptive thresholds indicative of long term pain was observed at 17 weeks following neonatal tail docking (P > 0.05). The present results highlight the potential for the use of measures of vocalisation to detect peri-procedural changes possibly associated with evoked pain. Nonetheless, activity and nociceptive measures failed to identify post-docking anomalies, suggesting that alternative methodologies need to be implemented to clarify whether tail docking is associated with short- and long-term changes attributable to pain experienced by the piglets.

Gene expression of mechanistic pain in pig spinal cord and dorsal root ganglia

Determination of stable reference genes for RT-qPCR expression data in mechanistic pain studies on pig dorsal root ganglia and spinal cord.

By Sandercock DA, Coe JE, Di Giminiani P, Edwards SA. 2017. Res Vet Sci. 2017 Sep 28;114:493-501.

RNA expression levels for genes of interest must be normalised with appropriate reference or “housekeeping” genes that are stably expressed across samples and treatments. This study determined the most stable reference genes from a panel of 6 porcine candidate genes: beta actin (ACTB), beta-2-microglobulin (B2M), eukaryotic elongation factor 1 gamma-like protein (eEF-1), glyceraldehyde-3-phosphate dehydrogenase (GAPDH), succinate dehydrogenase complex subunit A (SDHA), Ubiquitin C (UBC) in sacral dorsal root ganglia and spinal cord samples collected from 16 tail docked pigs (2/3rds of tail amputated) 1, 4, 8 and 16weeks after tail injury (4 pigs/time point). Total RNA from pooled samples was measured by SYBRgreen real-time quantitative PCR. Cycle threshold values were analysed using geNorm, BestKeeper and NormFinder PCR analysis software. Average expression stability and pairwise variation values were calculated for each candidate reference gene. GeNorm analysis identified the most stable genes for normalisation of gene expression data to be GAPDH>eEF-1>UBC>B2M>ACTB>SDHA for dorsal root ganglia and ACTB>SDHA>UBC>B2M>GAPDH>eEF-1 for spinal cord samples. Expression stability estimates were verified by BestKeeper and NormFinder analysis. Expression stability varied between genes within and between tissues. Validation of most stably expressed reference genes was performed by normalisation of calcitonin gene related polypeptide beta (CALCB). The results show similar patterns of CALCB expression when the best reference genes selected by all three programs were used. GAPDH, eEF-1 and UBC are suitable reference genes for porcine dorsal root ganglia samples, whereas ACTB, SDHA and UBC are more appropriate for spinal cord samples.