Monthly Archives: July 2016

Histopathological Characterization of Tail Injury and Traumatic Neuroma Development after Tail Docking in Piglets

Histopathological Characterization of Tail Injury and Traumatic Neuroma Development after Tail Docking in Piglets. By: D.A. Sandercock, S.H. Smith, P. Di Giminiani, S.A. Edwards, 2016. Journal of Comparative Pathology 155: 40-49.


Tail docking of neonatal pigs is widely used as a measure to reduce the incidence of tail biting, a complex management problem in the pig industry. Concerns exist over the long-term consequences of tail docking for possible tail stump pain sensitivity due to the development of traumatic neuromas in injured peripheral nerves. Tail stumps were obtained post mortem from four female pigs at each of 1, 4, 8 and 16 weeks following tail amputation (approximately two-thirds removed) by a gas-heated docking iron on post natal day 3. Tissues were processed routinely for histopathological examination. Non-neural inflammatory and reparative epidermal and dermal changes associated with tissue thickening and healing were observed 1 to 4 months after docking. Mild neutrophilic inflammation was present in some cases, although this and other degenerative and non-neural reparative changes are not likely to have caused pain. Traumatic neuroma and neuromatous tissue development was not observed 1 week after tail docking, but was evident 1 month after tail docking. Over time there was marked nerve sheath and axonal proliferation leading to the formation of neuromata, which were either localized and circumscribed or comprised of multiple axons dispersed within granulation tissue. Four months after tail resection, neuroma formation was still incomplete, with possible implications for sensitivity of the tail stump.

Corrigendum to “Histopathological Characterization of Tail Injury and Traumatic Neuroma Development after Tail Docking in Piglets” J Comp Pathol 155 (1) (2016) 40-49.

The authors wish to clarify terminology used in their paper entitled ‘Histopathological characterization of tail injury and traumatic neuroma development after tail docking in piglets’ and thank the Editor for the opportunity to do so. In the absence of a specific immunohistochemical label for detection of axons, the words ‘axon/axonal’ were inaccurately used and should be replaced by ‘Schwann cell’. Without more specific proof, it
certainly does not confirm, or necessarily infer, conduction. Secondly, ‘S100 neurofilament’ was inadvertently used instead of simply ‘S100’. The authors apologise for this error, which was wholly editorial on their part. Finally, in our opinion, the literature definitions of traumatic neuromas are such that there is likely to be some disagreement as to their required component features, particularly at different stages of lesion development, in different species and in different age groups of animals. In our paper, descriptions of traumatic neuroma presence and development were also based on haematoxylin and eosin staining and not solely confined to S100 immunolabelling. To this end, features such as variably-sized microfascicles, disorderly (often circumferential) neural proliferation and nerve fibres turning back on themselves are consistent with previous reports on traumatic neuromas in a number of species, including pigs.
While the aforementioned errors are regretted, this work was intended as a descriptive morphological characterization of a wide range of histopathological changes over known time points post docking. We have had some criticism that, due to our use of the word axonal, we have implied or claimed innervation, and thus pain sensation,
during the weeks after docking. This was not our intention – rather, our opinion is neutral in terms of whether or not traumatic neuromas are painful. The last sentence of the paper acknowledged that this work could not determine that. This study was considered descriptive and foundational, to serve as a platform for further investigation.
Its take-home message, irrespective of the error in terminology, is that neural proliferation consistent with traumatic neuroma development appears to be still ongoing at 16 weeks after tail docking.

Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision

Investigating the effect of rooting substrate provision on the group lying behaviour of pigs using machine vision. By: Abozar Nasirahmadi, Sandra A Edwards, Barbara Sturm,
Conference Paper · June 2016. Conference: CIGR-AgEng Conference, Aarhus, Denmark


To deliver good animal welfare, pigs should have a hygienic and undisturbed lying area within the pen. However, the provision of a rooting material is desirable to meet behavioural needs and this can only be given onto solid floor away from the dunging area, which might disrupt the group lying pattern. To determine whether daily provision of a rooting material (maize silage) onto a solid plate in the lying area of a fully slatted pen resulted in changed lying location, the lying patterns of pigs in 6 enriched pens were compared with those of 6 control pens which had only a suspended enrichment toy. Since visual monitoring of pig behaviours over long periods is very time consuming, an image
processing technique was applied to identify any changes pig lying positions and behaviour. Pigs were monitored by top view CCTV cameras and animals were extracted from their background using image processing algorithms. The x–y coordinates of each binary image were used for ellipse fitting algorithms to localize each pig. In order to find the lying positions, ellipse parameters were calculated for all fitted ellipses. Each pen was virtually subdivided into four zones in images and the centroid of each fitted ellipse was used for finding the position of each lying pig at 10 minute intervals during their lying period, after use of an algorithm to remove images in motion preceding the scan. By means of the ellipse properties it was possible to automatically find and compare the
changes in lying position of pigs in the pens. Results showed that once daily provision of rooting material did significantly change lying behaviour.

Omnivores Going Astray: A Review and New Synthesis of Abnormal Behavior in Pigs and Laying Hens

Omnivores Going Astray: A Review and New Synthesis of Abnormal Behavior in Pigs and Laying Hens, by Emma I. Brunberg, Bas Rodenburg, Lotta Rydhmer, Joergen B. Kjaer, Per Jensen and Linda J. Keeling. Front. Vet. Sci., 22 July 2016.


Pigs and poultry are by far the most omnivorous of the domesticated farm animals and it is in their nature to be highly explorative. In the barren production environments, this motivation to explore can be expressed as abnormal oral manipulation directed toward pen mates. Tail biting (TB) in pigs and feather pecking (FP) in laying hens are examples of unwanted behaviors that are detrimental to the welfare of the animals. The aim of this review is to draw these two seemingly similar abnormalities together in a common framework, in order to seek underlying mechanisms and principles. Both TB and FP are affected by the physical and social environment, but not all individuals in a group express these behaviors and individual genetic and neurobiological characteristics play an important role. By synthesizing what is known about environmental and individual influences, we suggest a novel possible mechanism, common for pigs and poultry, involving the brain–gut–microbiota axis.