The effects of environmental enrichment on the behaviour of suckling piglets and lactating sows: A review

Effect of Pig Synthetic Pheromones and Positive Handling of Pregnant Sows on the Productivity of Nursery Pigs

Weaning is one of the most important stress events in the life of pigs, increasing the risk for health problems and reduced performance. The release of pheromones in pig stables can be considered an environmental enrichment and alleviate the negative effects of weaning stress in nursery pigs. The present study investigated the effect of synthetic pheromones on the performance of nursery pigs. The effect of positive handling of sows in the farrowing house on the performance of the offspring in the nursery was also investigated. The study was performed in a commercial pig farm and included 24 batches of weaned piglets (216 piglets per batch). Half of the batches originated from sows exposed to positive handling. This implied that music was played from 6.00 a.m. to 6.00 p.m. from the moment the sows entered the farrowing house until weaning and that they were subjected to backscratching from the day they entered the farrowing unit the day of farrowing. During the nursery period, half of the batches were treated, and half served as controls. Piglets of treated groups were exposed to a synthetic analog of the maternal pig appeasing pheromone (PAP) (SecurePig®, Signs, Avignon, France). The product consisted of a gel block from which the pheromones were slowly released into the room. Different performance parameters were measured during the nursery period. Neither the sow treatment nor the treatment with pheromones significantly influenced the performance of the piglets during the nursery period (p > 0.05). The median values (95% confidence interval) of average daily gain, namely 318 (282-338) vs. 305 (272-322) g/day, feed conversion ratio, namely 1.64 (1.51-1.71) vs. 1.70 (1.57-1.75), and number of antimicrobial treatment days, namely 16.9 (9.6-25.0) vs. 17.3 (9.5-25.0) days, were numerically better in the nursery pigs exposed to the pheromones compared to the control groups. Mortality however was numerically higher in the treated groups, namely 4.4 (2.8-6.8) vs. 3.2 (0.9-4.2)%. Under the conditions of the present production system, pigs exposed to the pheromone treatment during the nursery did not show a significant performance increase.

Investigating risk factors behind piglet facial and sow teat lesions through a literature review and a survey on teeth reduction

Introduction

Piglet facial and sow teat lesions are the main reported reasons why pig producers routinely practice teeth resection. This is a painful procedure performed on piglets, where their needle teeth are clipped or ground to resect the pointed tip. The practice raises welfare concerns. In contrast to other procedures, such as tail docking, we know little about the risk factors for these two types of lesions.

Methods

We employed two methods to answer these questions: (1) reviewing the literature to identify potential risk factors, and (2) surveying pig production stakeholders worldwide to identify the occurrence of these lesions and the strategies used in practice that enable pig producers to manage or prevent these lesions while avoiding teeth resection. For the literature review, we used Google Scholar to include peer-reviewed publications and gray literature. We distributed the survey using convenience sampling and documented information on the current situation regarding teeth resection, including the methods, frequencies, and reasons for resecting piglets' teeth, the occurrence of piglet facial and sow teat lesions, and measures used to prevent and control these lesions.

Results

The literature review identified six major risk factors for both lesions, including the presence or absence of teeth resection, housing system, litter size, piglet management, environmental enrichment, milk production and other piglet management practices. However, most studies focused on the effects of the first two factors with very few studies investigating the other risk factors. There were 75 responses to the survey from 17 countries. The survey showed that half of the respondents practiced teeth resection with many recognizing that facial and teat lesions are the main reasons behind this practice. However, many producers used other interventions rather than teeth resection to prevent these lesions. These interventions focused on improving milk production of the sow, managing large litters, and providing environmental enrichment.

Discussion

More research is needed to validate these interventions and more science-based advice is needed to bridge the gap between research and practice to help more producers further understand the cause of piglet facial and sow teat lesions to transition toward the cessation of routine teeth resection.

Effects of Music Therapy on Neuroplasticity, Welfare, and Performance of Piglets Exposed to Music Therapy in the Intra- and Extra-Uterine Phases

Simple Summary

Environmental enrichment using music therapy can be used to improve animal welfare. Music, as an enrichment of the environment, is presented as an easy and viable way to remove the sterility of the breeding environment and make it more interesting and attractive. In this study, we aimed to evaluate the effects of auditory environmental enrichment in the pre- and postpartum period of sows on the behavior, performance, and neuro-plasticity of their piglets. Exposure to music in the last 1/3 of pregnancy and farrowing/lactation improved the weight of piglets at birth and weaning. Musical enrichment during pregnancy and lactation was able to cause changes in the piglets’ neuroplasticity and improve their productive performances.

Abstract

The rearing environment of pigs can cause a high level of stress due to the lack of stimuli and the impossibility of carrying out natural behaviors. Music therapy is a way to enrich the environment and promote stress relief. Few studies in swine using environmental enrichers focus on functional benefits, such as stress resilience, improved biological functions, or mental status. The effect of environmental enrichment on neurobiological processes is particularly poorly understood in farm animals. Thus, our study sought to elucidate the influence of music in piglets exposed to music therapy in the intrauterine and extrauterine phase on neuroplasticity, evaluating the levels of brain-derived neurotrophic factor (BDNF). Behavioural responses were also evaluated using fear tests related to stress resilience. The productive performance of these piglets was analysed to relate the possible reduction in stress levels to greater productivity gains. Forty-eight sows were used at 90 days of gestation until the weaning of their piglets. In the gestation phase, the sows were divided into two treatments: control (without music therapy) and music (with music therapy). In the farrowing/lactation phase, the sows were separated into four treatments: control-control (no music in any phase); control-music (music only in farrowing/lactation); music-control (music only during pregnancy); and music-music (music in both reproductive phases). Music therapy did not cause a difference in the BDNF levels of piglets at birth. However, piglets born from sows of the music-music treatment did not show a reduction in BDNF between birth and weaning, unlike the other treatments. Exposure to music in the last 1/3 of pregnancy and farrowing/lactation improved the weight of piglets at birth and at weaning. Musical enrichment during pregnancy and lactation was able to cause changes in the piglets’ neuroplasticity and improve their productive performances.

Welfare of pigs on farm

This scientific opinion focuses on the welfare of pigs on farm, and is based on literature and expert opinion. All pig categories were assessed: gilts and dry sows, farrowing and lactating sows, suckling piglets, weaners, rearing pigs and boars. The most relevant husbandry systems used in Europe are described. For each system, highly relevant welfare consequences were identified, as well as related animal-based measures (ABMs), and hazards leading to the welfare consequences. Moreover, measures to prevent or correct the hazards and/or mitigate the welfare consequences are recommended. Recommendations are also provided on quantitative or qualitative criteria to answer specific questions on the welfare of pigs related to tail biting and related to the European Citizen's Initiative 'End the Cage Age'. For example, the AHAW Panel recommends how to mitigate group stress when dry sows and gilts are grouped immediately after weaning or in early pregnancy. Results of a comparative qualitative assessment suggested that long-stemmed or long-cut straw, hay or haylage is the most suitable material for nest-building. A period of time will be needed for staff and animals to adapt to housing lactating sows and their piglets in farrowing pens (as opposed to crates) before achieving stable welfare outcomes. The panel recommends a minimum available space to the lactating sow to ensure piglet welfare (measured by live-born piglet mortality). Among the main risk factors for tail biting are space allowance, types of flooring, air quality, health status and diet composition, while weaning age was not associated directly with tail biting in later life. The relationship between the availability of space and growth rate, lying behaviour and tail biting in rearing pigs is quantified and presented. Finally, the panel suggests a set of ABMs to use at slaughter for monitoring on-farm welfare of cull sows and rearing pigs.

Postpartum dysgalactia syndrome in sows: effects on behavior of sows and piglets

BACKGROUND

To investigate if specific sow and piglet behavioral characteristics could be used diagnostically, this case-cohort study of the behavior of sows and piglets during the periparturient period (from 24 h before the birth of first piglet to 24 h after the birth of last piglet) was conducted. Data included 32 sows diagnosed with PDS (PDS+) vs. 37 healthy matched controls (PDS-) and their litters.

RESULTS

A significant change from active behavior with many postural changes to a more passive behavior was noted in connection with parturition. Sow nesting behavior was less frequent in PDS+ sows compared to PDS- sows during (p = 0.04) and after parturition (p = 0.0004). No difference was found between PDS+ and PDS- in the number of postural changes, interval from last time standing to the birth of the first piglet, interval from last time eating/drinking to the birth of the first piglet, interval from the birth of the first piglet to the sow standing after farrowing, interval from the birth of the last piglet until eating/drinking, occurrence of bar biting, or frequency or duration of eating/drinking during the observation period. Piglets of PDS+ sows stayed outside the creep areas more often than piglets of PDS- sows (p < 0.0001), but there was no difference in the mean number of piglets observed massaging the udder every 10 min.

CONCLUSION

These results confirm that sow behavior changes from active before parturition to more passive after parturition. Being diagnosed with PDS affected the periparturient behavior of sows as well as their piglets. The observed reduction in nesting behavior in PDS+ sows may suggest that a highly motivated piglet-oriented behavior was affected. However, classical sickness behaviors like lethargy and passivity seem to be poor markers for PDS.

Management and Feeding Strategies in Early Life to Increase Piglet Performance and Welfare around Weaning: A Review

The performance of piglets in nurseries may vary depending on body weight, age at weaning, management, and pathogenic load in the pig facilities. The early events in a pig's life are very important and may have long lasting consequences, since growth lag involves a significant cost to the system due to reduced market weights and increased barn occupancy. The present review evidences that there are several strategies that can be used to improve the performance and welfare of pigs at weaning. A complex set of early management and dietary strategies have been explored in sows and suckling piglets for achieving optimum and efficient growth of piglets after weaning. The management strategies studied to improve development and animal welfare include: (1) improving sow housing during gestation, (2) reducing pain during farrowing, (3) facilitating an early and sufficient colostrum intake, (4) promoting an early social interaction between litters, and (5) providing complementary feed during lactation. Dietary strategies for sows and suckling piglets aim to: (1) enhance fetal growth (arginine, folate, betaine, vitamin B12, carnitine, chromium, and zinc), (2) increase colostrum and milk production (DL-methionine, DL-2-hydroxy-4-methylthiobutanoic acid, arginine, L-carnitine, tryptophan, valine, vitamin E, and phytogenic actives), (3) modulate sows' oxidative and inflammation status (polyunsaturated fatty acids, vitamin E, selenium, phytogenic actives, and spray dried plasma), (4) allow early microbial colonization (probiotics), or (5) supply conditionally essential nutrients (nucleotides, glutamate, glutamine, threonine, and tryptophan).

On-Farm Welfare Assessment Protocol for Suckling Piglets: A Pilot Study

Piglets experience welfare issues during the nursery phase. This pilot study aimed to test a protocol for identifying the main welfare issues in suckling piglets and to investigate relationships among animal-based indicators and management conditions. Litters (n = 134), composed of undocked and tail-docked piglets, were assessed at two farms. After birth, observations were made at the age of 7 days and 20 days. At each observation, housing conditions (HCs) were measured, and 13 animal-based indicators, modified from Welfare Quality, Classyfarm, Assurewel and others introduced ex novo, were recorded. A generalized linear mixed model was used, considering animal-based indicators as dependent variables and farm, piglets' age, tail docking and HCs as independent variables. The main welfare issues were lesions of the limb (32.6%) and the front area of the body (22.8%), a poor body condition score (BCS) (16.1%), ear lesions (15.5%), and tail lesions (9.7%). Negative social behaviour (e.g., fighting and biting) represented 7.0% of the active behaviour, with tail biting observed in 8.7% of the piglets. While lesions on the front areas of the body were mostly associated with the farm, tail lesions, low BCS, tear staining, and diarrhoea were associated with light and nest temperature (p < 0.05). In particular, tail biting increased with scarce light (p = 0.007). Tail docking did not influence any animal-based indicator except for tear staining which was higher in the tail-docked as compared to the undocked piglets (p = 0.05), increasing awareness on this practice as a source of negative emotion in piglets. The protocol tested may be a promising tool for assessing on-farm piglets' welfare.

Effects of Different Farrowing Environments on the Behavior of Sows and Piglets

Simple Summary

The farrowing crate has long been a severe welfare problem of sows as its space restriction greatly impairs the behavioral expression of sows and induces long-term stress. We aimed to investigate the behavioral pattern of sows and piglets reared under different farrowing systems a farrowing crate and free farrowing pens with sloping walls with or without nest materials. Sows and piglets in free farrowing pens had a higher level of activity and lower level of performing abnormal behaviors. Providing nest material enhanced the beneficial effect of free farrowing system on the behavior of sows and piglets. These results encourage us to introduce the free farrowing systems to the pig industry and thus improve the welfare condition of farrowing sows. However, improved managements should be investigated as the piglet loss in the free farrowing systems tended to be higher than that in the farrowing crate system.

Abstract

We investigated the effect of different farrowing systems on the behavior of sows and piglets. In total, 22 hybrid sows (Yorkshire × Landrace) were randomly assigned into three farrowing systems, farrowing crate (FC), free farrowing pen with sloping walls (FFS), and free farrowing pen with sloping walls and nest materials (FFSN). The FFS and FFSN sows were more active, and exhibited less abnormal behaviors compared with the FC sows before and after parturition. FFS and FFSN piglets were more active compared with FC piglets. The increased activity of the FFS and FFSN sows might encourage the activity of their piglets, resulting in more proximity to sow behavior of their piglets. Providing nest materials improved the investigative behavior of sows and piglets. The total mortality of piglets in the free farrowing systems tended to be higher compared with the farrowing crate system. In conclusion, free farrowing system has beneficial effects on the behavior of sows and piglets but extra care in management needs to be taken to avoid piglet loss. Adding nest material in the farrowing pens is suggested to enrich the behavioral pattern of sows and piglets.

Enrichment with Lucerne Hay Improves Sow Maternal Behaviour and Improves Piglet Survival

This study investigated the effects of providing lucerne hay on the behaviour and the performance of sows housed in farrowing crates during farrowing and lactation. Seventy-two mixed parity sows received either 1 kg lucerne hay daily from entry into the farrowing crate (-2 d from expected farrowing date) until weaning at 17 d (lucerne group, n = 36), or received no additional enrichment (control group, n = 36). In the 18 h prior to farrowing, the sows in the lucerne treatment spent more time performing nest-building behaviour (14.8% lucerne vs 11.1% control, p = 0.0009) and less time sham-chewing (1.0% lucerne vs 1.9% control, p = 0.01) than control sows, and gave birth to fewer stillborn piglets/litter (0.1 lucerne vs 0.4 control, p = 0.027). After farrowing (Day 3), the control sows spent less time lying than the lucerne sows (26% control vs 43% lucerne, p < 0.05). The control sows also spent less time interacting with their piglets during early lactation compared to late lactation (25.5% Day 5 vs 47.3% Day 12, p < 0.05), suggesting reduced maternal behaviour in this group. The lucerne sows continued to interact with the lucerne throughout lactation, indicating that they still found the enrichment rewarding after the nesting period had ceased. Based on these results, lucerne enrichment was considered to improve sow welfare during farrowing and lactation and reduce the number of stillborn piglets.

Providing Effective Environmental Enrichment to Pigs: How Far Have We Come?

Science has defined the characteristics of effective environmental enrichment for pigs. We provide an overview of progress towards the provision of pig enrichment in the three largest global pork producing regions. In the USA, enrichment has not yet featured on the policy agenda, nor appeared on farms, except when required by certain farm assurance schemes. China has very limited legal animal welfare provisions and public awareness of animal welfare is very low. Food safety concerns severely restrict the use of substrates (as enrichment) on farms. Providing enrichment to pigs is a legal requirement in the EU. In practice, enrichment is not present, or simple (point-source) objects are provided which have no enduring value. Other common issues are the provision of non-effective or hazardous objects, inadequate presentation, location, quantity and size or inadequate maintenance of enrichment. Improvements can be made by applying principles from the field of experimental analysis of behaviour to evaluate the effectiveness of enrichment; providing welfare knowledge transfer, including training and advisory services; highlighting the economic benefits of effective enrichment and focusing on return on investment; increasing pressure from the financial sector; using novel drivers of change, such as public business benchmarking. The poor implementation of scientific knowledge on farms suggests that the pig industry has not fully embraced the benefits of effective enrichment and is still a long way off achieving an enriched pig population.

Effect of enriched housing on welfare, production performance and meat quality in finishing lambs: the use of feeder ramps

This study analyses the effect of environmental enrichment on the welfare, productive traits and meat quality of lambs housed in feedlots. Sixty lambs were placed in enriched (EE) or conventional (CO) pens (3 pens for each treatment, 10 lambs/pen) where EE had a wooden platform with ramps that provided access to a concentrate hopper, cereal straw as bedding and forage, and one play ramp. The CO pen was barren, similar to commercial feedlots. The physiological adaptation response of EE lambs was more efficient than CO, since the latter mobilised more body reserves (i.e., increased NEFA, P<0.05), and had lower levels of immunity (i.e., increased N/L, P<0.05), which indicate chronic stress, probably associated with the barren environment. The EE lambs had a higher (P<0.05) average daily gain, with heavier carcasses and higher fattening scores, as well as lower pHult, higher L and b values, and lower values of texture (P<0.05).

Reproductive issues in welfare-friendly housing systems in pig husbandry: a review

In Europe, housing conditions of sows are currently changing, related with a larger emphasis on pig welfare. As a result, sows are and will be less kept in crates, but more so in loose housing systems (farrowing, lactation) and group housing systems (pregnancy, lactation, weaning-to-oestrus interval). These changes in housing conditions may affect reproductive functioning of the sows. Group housing of sows may decrease farrowing rate and litter size when stress levels rise or when feed intake in early pregnancy is not fully secured. Loose housing during farrowing results in an improved farrowing process, but may increase piglet mortality by crushing during early lactation. Further, group housing during lactation may increase the risk of lactational oestrus. Thus, new - welfare friendly - housing systems require increased attention to management to ensure optimal reproductive performance.