Exploratory study of the effects of intra-uterine growth retardation and neonatal energy supplementation of low birth-weight piglets on their post-weaning cognitive abilities

peer-reviewedThe present study investigated the effects of intra-uterine growth retardation (IUGR, score 0–3; i.e., “normal” to “severe”) level at birth, and the effects of neonatal energy supplementation (dosed with 2 ml of coconut oil, commercial product or water, or sham-dosed), on post-weaning cognitive abilities of low birth-weight piglets (<1.1 kg). In total, 184 piglets were recruited at weaning (27±0.1 days) for habituation to the test procedures, and were either tested for spatial learning and memory in a T-maze (n=42; 37±0.5 days) or for short-term memory in a spontaneous object recognition task (SORT; n=47; 41±0.3 days). Neonatal supplementation did not affect performances of pigs in the T-maze task or SORT. IUGR3 pigs tended to be faster to enter the reward arm and to obtain the reward in the reversal step of the T-Maze task, suggesting a better learning flexibility, compared to IUGR1 (entry t72.8=2.9, P=0.024; reward t80=3.28, P=0.008) and IUGR2 (entry t70.3=2.5, P=0.068; reward t73.9=2.77, P=0.034) pigs. However, a higher percentage of IUGR1 pigs tended to approach the novel object first (DSCF-value=3.07; P=0.076) and to interact with it more (t40=2.19, P=0.085), relative to IGUR3 pigs. IUGR1 pigs showed a strong preference for the novel object, as they had a greater percentage time difference interacting with the objects when the novel object was presented (t81=−3.41, P=0.013). In conclusion, some low birth-weight piglets are able to perform a spatial task and an object recognition test, but performances in these tests may be modulated by IUGR level.Department of Agriculture, Food and the Marin

Investigating management strategies of large litters in pigs

Modern hyper-prolific sows often do not have enough teats to feed all of their piglets. The resulting competition for colostrum and milk hampers piglet growth and survival. This is exacerbated by low birth-weights, which are also common in large litters. Three experiments were conducted for this thesis; each investigated a management strategy hypothesised to improve outcomes for piglets from large litters. The first experiment evaluated the use of nurse sows to rear supernumerous piglets (i.e. when there are more piglets than teats). At 1 day old, piglets from large litters either remained with their mother or were moved to a nurse sow who was either 7 or 21 days into lactation. Aspects of piglet (growth, survival and suckling behaviour) and sow (salivary cortisol, back-fat thickness, body lesions, and nursing behaviour) welfare were monitored until weaning. Rearing by a nurse sow did not compromise pre-weaning survival, compared to rearing by the mother, regardless of the nurse sows’ stage of lactation (7 or 21 days) when the piglets were transferred to her. Piglets reared by a nurse sow were initially heavier than piglets remaining with their dam, but all piglets were weaned at similar weights. Regardless of whether a nurse sow or biological mother, sows in late lactation had shorter nursing bouts and their litter showed more fighting behaviour, compared to sows in early lactation. Despite longer lactation length, nurse sows did not differ from biological mothers in salivary cortisol concentration, backfat thickness and body lesion scores. The second experiment looked at using an artificial rearing system to rear 7 day old piglets until weaning. Litters of 12 piglets were assigned at 7 days old to be either sow-reared (SR) or artificially-reared (AR) until weaning. Pre-weaning survival, growth and behaviour were recorded, emotional state was assessed using Qualitative Behavioural Assessment pre- and post-weaning, and reactivity tests were conducted post-weaning. Survival did not differ between treatments. AR piglets were lighter than SR piglets from the day following transfer until weaning. They performed more negative behaviours (belly-nosing, ear and tail biting) and their emotional state was scored lower pre-weaning, compared to SR piglets. However, post-weaning the emotional state of AR piglets was scored higher than SR pigs and AR piglets had a lower emotional reaction to a fear test (startling event) and human contact. The third experiment evaluated whether 2ml of an energy-rich neonatal supplement (coconut oil or a commercial product) would enhance survival and vitality of low birth-weight piglets. At three hours post-birth, low birthweight piglets (<1.1 kg) were dosed with one of the supplements, water, or sham-dosed. Blood glucose content, rectal temperature, and pre-weaning survival and growth were recorded but none were affected by treatment. Post-weaning, piglets were tested for spatial learning and memory in a T-maze set-up, or were tested for short-term memory in a spontaneous object recognition test. There were no treatment differences on the performance of pigs in any of the two tests, meaning that the birth energy supplementation did not enhance post-weaning cognitive performances. This thesis demonstrated that a single dose of energy supplementation at birth did not improve outcomes for low birth-weight piglets, and that the rearing strategies to promote piglet survival in large litters do work in terms of survival but can impair some aspects of piglet welfare and development. The most pronounced welfare impacts were observed with artificial rearing. Therefore management of large litters remains a significant challenge and the strategies investigated deserve further improvements

Use of the Confusion Assessment Method in multicentre delirium trials: training and standardisation

BACKGROUND Delirium occurs commonly in older adults and is associated with adverse outcomes. Multicentre clinical trials evaluating interventions to prevent delirium are needed. The Confusion Assessment Method (CAM) is a validated instrument for delirium detection. We hypothesised it would be possible for a large feasibility study to train a large number of research assistants, with varying experience levels, to conduct CAM assessments reliably in multiple hospital sites. METHODS A standardised training programme was followed, incorporating structured training at a central location and at study sites. CAM practice sessions on both delirious and non-delirious patients by research assistants were conducted and, thereafter, there was ongoing inter-rater reliability assessment on the CAM between research assistant pairs at study sites. The setting was eight acute care hospitals in England and Wales. Participants were research assistants working on a multicentre feasibility study of delirium prevention. The measurement used was the Confusion Assessment Method. RESULTS Thirty-seven research assistants were trained in CAM assessment and 33 returned training logs. The logs showed there was 100% overall agreement between research assistant pairs on 295 CAM assessments, of which 263 (89.2%) were negative for delirium and 32 (10.8%) were positive. In the course of the feasibility study, research assistants successfully completed 5,065 (89.7%) of the 5,645 expected CAM assessments, with minimal missing data. CONCLUSION Using the training methods described in this study, it is possible to achieve high quality delirium assessments for large numbers of patients with little missing data across geographically dispersed sites in multicentre studies. The standardisation of multisite delirium assessments is an important contribution to research methodology, and provides a much-needed advance for the field. TRIAL REGISTRATION ISRCT ISRCTN01187372. Registered 13 March 201