Sarah H. Ison

Prenatal stress produces anxiety prone female offspring and impaired maternal behaviour in the domestic pig

Numerous studies have shown that prenatal stress (PNS) can have profound effects on postnatal well-being. Here, the domestic pig (Sus scrofa) was used to investigate PNS effects owing to the direct relevance for farm animal welfare and the developing status of the pig as a large animal model in translational research. Pregnant primiparous sows were exposed, in mid-gestation, to either a social stressor (mixing with unfamiliar conspecifics) or were kept in stable social groups. The ratio of levels of mRNAs for corticotropin releasing hormone (CRH) receptors 1 and 2 in the amygdala, measured for the first time in the pig, was substantially increased in 10-week-old female, but not male, PNS progeny indicating a neurobiological propensity for anxiety-related behaviour. Mature female offspring were observed at parturition in either a behaviourally restrictive crate or open pen. Such PNS sows showed abnormal maternal behaviour in either environment, following the birth of their first piglet. They spent more time lying ventrally, more time standing and showed a higher frequency of posture changes. They were also more reactive towards their piglets, and spent longer visually attending to their piglets compared to controls. Associated with this abnormal maternal care, piglet mortality was increased in the open pen environment, where protection for piglets is reduced. Overall, these data indicate that PNS females have their brain development shifted towards a pro-anxiety phenotype and that PNS can be causally related to subsequent impaired maternal behaviour in adult female offspring.

Attitudes of farmers and veterinarians towards pain and the use of pain relief in pigs.

A survey of UK-based pig farmers and veterinarians was conducted, in order to investigate attitudes to pain and the use of pain relief in pigs. Survey respondents were asked to indicate which anti-inflammatory drugs they used or prescribed for pigs, how often these were administered, and the level of pain they associated with particular conditions. The survey found that veterinarians used a range of anti-inflammatory products to treat pigs with lameness. While both farmers and veterinarians gave similar pain scores overall, farmers rated gastrointestinal disease as more painful and conversely veterinarians scored lameness higher. Female and younger respondents gave higher pain scores than males and older respondents. Overall, farmers and veterinarians had a positive attitude towards pain relief in pigs with the majority agreeing that animals recovered more promptly when pain relief was administered. Most farmers agreed that the recognition and management of pain is an important part of pig husbandry, and many expressed an interest in finding out more about identifying pain in this species as well as the treatment options available. The study highlighted potential barriers to the increased application of pain relief in pigs in that almost one-third of veterinarians and two-thirds of farmers did not agree that they discussed pain management with each other, while other respondents indicated that they found it difficult to recognise pain in pigs, and did not know how to treat it appropriately.

The identification of potential behavioural indicators of pain in periparturient sows

Periparturient pain is a welfare concern and could contribute to piglet losses. This has led to studies investigating post-farrowing analgesia. A clear reduction in pain has not been demonstrated, partly due to a lack of pain indicators. This study quantified behaviours as potential pain indicators (PPIn) in sows: i) before, during and after farrowing, and ii) 2min before and after piglet births. Twenty-five sows were observed during and after, and ten pre-farrowing. Behaviour recorded included: 1) back leg forward (back leg pulled forward and/or in); 2) tremble (movement as if shivering); 3) back arch (leg(s) stretch forming an arched back); 4) paw (leg scraped in pawing motion); and 5) tail flick (tail moved rapidly up and down). Behaviours were analysed using generalized linear models and Spearmans rank correlations. All PPIn were rare or absent pre-farrowing, highest during farrowing, and back leg forward, tremble and back arch were greater in the early post-farrowing period. Several significant positive correlations between PPIn during and post-farrowing were found. Back arch, tail flick and paw were higher before than after a piglet birth, and were more frequent earlier in the birth order. Back leg forward and tremble did not differ before and after births, and tremble increased with birth order. These behaviours, which were absent or rare pre-farrowing, present during farrowing and were lower afterwards, and showed consistent individual variation, may be quantitatively associated with pain. Spontaneous behaviours could be used to test the efficacy of analgesics or identify sows that may benefit.

A Review of Pain Assessment in Pigs

There is a moral obligation to minimize pain in pigs used for human benefit. In livestock production, pigs experience pain caused by management procedures, e.g., castration and tail docking, injuries from fighting or poor housing conditions, “management diseases” like mastitis or streptococcal meningitis, and at parturition. Pigs used in biomedical research undergo procedures that are regarded as painful in humans, but do not receive similar levels of analgesia, and pet pigs also experience potentially painful conditions. In all contexts, accurate pain assessment is a prerequisite in (a) the estimation of the welfare consequences of noxious interventions and (b) the development of more effective pain mitigation strategies. This narrative review identifies the sources of pain in pigs, discusses the various assessment measures currently available, and proposes directions for future investigation.

The effect of late pregnancy supplementation of ewes with vitamin E on lamb vigour.

The experiment measured lamb responses to supplementation of the pregnant ewe diet with vitamin E above requirement. Crossbred ewes were mated with either Suffolk or Texel rams. Twin-bearing ewes were randomly allocated (approximately 21 months of age at allocation) to one of four treatment groups (20 ewes per group, 10 mated with Suffolk and 10 with Texel rams). Treatments imposed were 50, 100, 150 or 250 IU supplementary vitamin E per ewe per day to give a four treatment by two sire-type factorial experimental design. Ewes were fed concentrates to meet energy requirements for stage of pregnancy and hay ad libitum. Diets were introduced approximately 6 weeks before lambing. Blood samples were obtained prior to introduction of diets, 17 days after introduction of diets and within 24 h of lambing from a subset of eight ewes per treatment (32 total). Colostrum samples were obtained from 10 ewes per treatment, 12 h after birth of the first lamb. All births were observed and a lamb vigour score was assigned to each lamb 5 min after birth. At 1 and 12 h after birth, rectal temperature, and at 12 h after birth, sex, crown-rump length and BW of each lamb were recorded. Mean ewe plasma α-tocopherol concentration prior to introduction of the diets was 1.5 μg/ml (s.e.m. 0.09) and did not differ between groups. There were positive linear (P < 0.001) effects of dietary vitamin E on plasma (17 days after introduction of diets) and colostrum (12 h after birth) α-tocopherol concentrations. Lamb vigour scores were superior (P < 0.001) for lambs sired by Texel rather than Suffolk rams but there were no differences as a result of vitamin E supplementation. Lamb mortality was low and unrelated to either sire or supplementary vitamin E. Lamb birth and weaning weights were also unaffected by vitamin E supplementation. Supplementing the ewe with vitamin E therefore had no effect on any lamb measurements.

Behavioral and physiological responses of primiparous sows to mixing with older, unfamiliar sows

Pigs are mixed into new social groups at various stages of production, and this study investigated the response of gilts to mixing with older unfamiliar sows. Four groups of 6 gilts and 1 group of 5 gilts were housed in stable groups until the most recently bred female reached d 39 of gestation. Then, stable groups were split such that 15 gilts remained in their home pens (CON) and 14 gilts were mixed (MIX) with 3 multiparous sows for 1 wk (M1), returned to the home pen for 1 wk, and then mixed with 3 different sows for 1 wk (M2). Continuous behavioral observations of gilt location in the pen, posture, aggressive, and other social interactions were made from the start of M1 and M2 for 5 h. Five-minute scans of location, posture, and behavior as well as salivary cortisol measurements were taken before, during, and after each mix week, whereas skin lesions were counted before and after each mix. During the mixed period, MIX gilts spent more (P ≤ 0.009) time in the individual feeding stalls, ventral lying, sitting, involved in aggression, and idle and less (P < 0.001) time in the straw-bedded area, lateral lying, and performing exploratory behavior (chewing, nosing, and rooting) than CON gilts. Additionally, MIX gilts had greater (P < 0.001) salivary cortisol concentrations and accumulated more (P < 0.001) skin lesions during mixing sessions compared to CON gilts. Mixed gilts in M2 spent more (P ≤ 0.013) time in the feeding stalls and ventral lying and less (P ≤ 0.029) time standing and in the dunging passageway compared to M1. Compared to M1, gilts had lower (P < 0.001) salivary cortisol concentrations and fewer (P ≤ 0.027) lesions in front and middle regions of the body during M2. During M2, salivary cortisol concentration was positively correlated with time spent in the dunging passageway (Spearmans rank correlation [rs] = 0.650, P = 0.022) and negatively correlated with time spent in the feeding stalls (rs = -0.762, P = 0.004). Results indicated that gilts adapted their behavior during M2 by using the feeding stalls more, and they became less active, especially when interacting with the sows. Despite this adaptation in M2, lesions and salivary cortisol in M IX gilts were much greater than in CON gilts, highlighting the severity of mixing gilts with multiparous sows.

A survey of sow management at farrowing in the UK

Farrowing is an important period in pig production, with sow health and piglet mortality representing a welfare issue and an economic loss. Sow health and welfare is critical for piglet survival and good management can improve welfare and productivity. This study investigated the management of sows around farrowing and attitudes of UK pig farmers towards sow pain and difficulty farrowing. Farmers were asked how often they provided night checks, used farrowing induction and administered pharmaceutical products during and after farrowing. Farmers and veterinarians were asked if they used or prescribed anti-inflammatories for farrowing-related health issues. Farmers were asked if pain at farrowing was a problem for gilts and sows and what percentage they considered to have difficulty farrowing. Convenience sampling using a number of distribution methods was used. Sixty-one farmers and 52 veterinarians responded. Of the farmer respondents, ten worked on outdoor and 51 on indoor farms. Night checks were reported as frequently provided and farrowing induction was rare. Many respondents reported using oxytocin substitutes at least sometimes during (74%) or after (54%) farrowing. Azaperone was reported to be used at least sometimes by 45% of respondents during and 33% after farrowing. Farmers indicated that pain at farrowing was more often a problem for gilts than sows and 5% of gilts and 4% of sows were considered to have farrowing difficulty. The high level of supervision around farrowing, with the use of night checks, is encouraging and could improve welfare. Frequent use of oxytocin substitutes, which promote farrowing and milk let-down may negatively impact sow and piglet welfare and could be masking poor mothers that fail to perform well without intervention. This study provides interesting information regarding the management of sows around farrowing, which could inform future research and education to improve sow and piglet welfare in the periparturient period.

Periparturient behavior and physiology: further insight into the farrowing process for primiparous and multiparous sows

Giving birth is a critical time for many species and is often the most painful event ever experienced by females. In domestic species, like the pig, pain associated with parturition represents a potential welfare concern, and the consequences of pain can cause economic losses (e.g., by indirectly contributing to piglet mortality as pain could slow post-farrowing recovery, reduce food and water intake, reducing milk let-down). This study investigated pain assessment and its management in primiparous (gilts) and multiparous (sows) breeding pigs, including the provision of a non-steroidal anti-inflammatory drug (NSAID) post-parturition. Individuals were randomly allocated to receive the NSAID ketoprofen (3 mg/kg bodyweight) (n = 11 gilts, 16 sows) or the equivalent volume of saline (n = 13 gilts, 16 sows) by intramuscular injection 1.5 h after the birth of the last piglet. Data collected included putative behavioral indicators of pain (back leg forward, tremble, back arch), salivary cortisol concentrations pre-farrowing and up to 7 days post-injection. In addition, post-partum biomarkers of inflammation, including the acute phase protein C-reactive protein (CRP) and 3 porcine cytokines [interleukin-1 β (IL1 β), interleukin-6 (IL6), and tumor necrosis factor α (TNF α)] were measured in plasma collected 6 h following the injection. Behaviors were analyzed using generalized linear mixed models, and physiological variables with linear mixed models. No difference in putative pain behaviors, salivary cortisol, CRP, or cytokines were found between individuals treated with ketoprofen or those administered the saline control. However, there were some differences between gilts and sows, as sows exhibited more putative pain behavior than gilts, had higher salivary cortisol on the day of farrowing and had higher plasma TNF α. Conversely, gilts had higher salivary cortisol than sows on day 3 post-farrowing and had higher CRP. This indicates that, like human females, multiparous sows experience more pain from uterine activity following birth than primiparas. This study provides useful information for developing management practices relating to post-farrowing care for breeding pigs.