Ewes Direct Most Maternal Attention towards Lambs that Show the Greatest Pain-Related Behavioural Responses

<div><p>Although neonatal farm animals are frequently subjected to painful management procedures, the role of maternal behaviour in pain coping, has not been much studied. We investigated whether ewes were able to distinguish between lambs in pain and those that were not, and whether their behaviour altered depending on the severity of lamb pain. Eighty male lambs were allocated to one of 4 pain treatments within 24 hours of birth. Lambs were either handled only (C), bilaterally castrated with tight rubber rings (RR), as for RR but with the application of a Burdizzo clamp immediately proximal to the ring (Combined) or subjected to short scrotum castration (SSC) where the testicles were retained within the abdomen and only the scrotum removed. The behaviour of the ewe, treated lamb and untreated sibling where present (n = 54) were recorded for 30 minutes after treatment. Castration treatment increased the expression of abnormal standing and lying postures, specific pain-related behaviours (head-turning, stamping/kicking, easing quarters, tail wagging) and composite pain scores (P<0.001 for all). The greatest expression of pain-related behaviours was shown by lambs in the RR group, which were the only group to show rolling responses indicative of severe pain, followed by the SSC group. Ewes expressed more licking/sniffing responses to the RR and SSC lambs than towards the Combined and C lambs (P<0.05), and oriented most to RR lambs and least to C lambs (P<0.001). Ewes with two lambs also directed more attention towards the treated than the untreated lamb (P<0.001). The quantity of maternal care directed towards the lamb was positively correlated with the expression of active pain behaviours. The data demonstrate that ewes are able to discriminate between lambs in pain and those that are not, and that their response is increased with a greater severity of pain.</p></div

Papel da luminosidade do biotério no comportamento do rato no labirinto em cruz elevado Role of vivarium illumination in rat behavior in the elevated plus-maze

Há pouca informação sobre o efeito dos ambientes onde os ratos são mantidos antes de testes. Para investigar o efeito da iluminação do biotério, ratos Wistar machos foram submetidos a um período de 96 h de iluminação contínua, escuridão contínua ou um ciclo claro escuro de 12:12 h e testados no labirinto em cruz elevado em uma sala iluminada (150 lux) ou escura (0 lux). Os resultados mostram que nem a iluminação contínua nem a escuridão contínua do biotério afetam o comportamento dos ratos, quando comparados aos sujeitos mantidos no ciclo claro-escuro de 12 h. A condição de luminosidade durante o teste, no entanto, foi importante: independentemente da condição de iluminação do biotério, os animais testados no escuro exploraram mais os braços abertos do labirinto, um resultado já relatado na literatura e interpretado como diminuição da ansiedade nesse aparato.<br>There is little information about the environments where rats are kept before being tested. In order to investigate the role of vivarium illumination, male Wistar rats were submitted to a 96-h period of continuous illumination, continuous dark or a 12:12 h light/dark cycle and tested in the elevated plus-maze in a lit (150 lux) or a dark room (0 lux). Results showed that neither vivarium illumination nor darkness for 96 h altered the rats' behavior in comparison to that of rats kept under the 12-h light/dark cycle. Luminosity during the test, however, was important: no matter what the vivarium illumination was, rats tested in the dark room explored more the open arms of the maze, an already reported result which is interpreted as decreased anxiety in this apparatus

Neuroleptic Drugs Revert the Contextual Fear Conditioning Deficit Presented by Spontaneously Hypertensive Rats: A Potential Animal Model of Emotional Context Processing in Schizophrenia?

Schizophrenia, bipolar disorder, and attention deficit/hyperactivity disorder (ADHD) present abnormalities in emotion processing. A previous study showed that the spontaneously hypertensive rats (SHR), a putative animal model of ADHD, present reduced contextual fear conditioning (CFC). The aim of the present study was to characterize the deficit in CFC presented by SHR. Adult male normotensive Wistar rats and SHR were submitted to the CFC task. Sensitivity of the animals to the shock and the CFC performance after repeated exposure to the task were investigated. Pharmacological characterization consisted in the evaluation of the effects of the following drugs administered previously to the acquisition of the CFC: pentylenetetrazole (anxiogenic) and chlordiazepoxide (anxiolytic); methylphenidate and amphetamine (used for ADHD); lamotrigine, carbamazepine, and valproic acid (mood stabilizers); haloperidol, ziprasidone, risperidone, amisulpride, and clozapine (neuroleptic drugs); metoclopramide and SCH 23390 (dopamine antagonists without antipsychotic properties); and ketamine (a psychotomimmetic). The effects of paradoxical sleep deprivation (that worsens psychotic symptoms) and the performance in a latent inhibition protocol (an animal model of schizophrenia) were also verified. No differences in the sensitivity to the shock were observed. The repeated exposure to the CFC task did not modify the deficit in CFC presented by SHR. Considering pharmacological treatments, only the neuroleptic drugs reversed this deficit. This deficit was potentiated by proschizophrenia manipulations. Finally, a deficit in latent inhibition was also presented by SHR. These findings suggest that the deficit in CFC presented by SHR could be a useful animal model to study abnormalities in emotional context processing related to schizophrenia