Group space allowance has little effect on sow health, productivity, or welfare in a free-access stall system1,2

Gilts prefer an open pen to a stall

Stalls or crates are a very common type of housing used on pig farms that restrict an animal's movement. How this confinement impacts the animal's affective states is seldom investigated. We conducted a preference test over 7 days where trios of gilts (n = 10 trios, 27.4 ± 1.5 weeks old) had free access between individual self-locking stalls (~ 1.2 m2) and a shared open area allowing 2.8 m2/animal (71% of total area). Gilts had access to ad libitum feed and water both inside the crates and in the open area. After 7 days, personality traits of the animals were assessed with open field (OF) and novel object (NO) tests. Principal Component Analysis (PCA) yielded two main components, which we defined as Passivity and Engagement. The median time spent outside the crate was 95.2% as 21/29 of the gilts exhibited a significant preference for pen over crate during the 7-day trial (p < 0.05). Passivity had no relationship with time spent in the open area, but engagement during OF/NO was associated with less use of the open area (OR = 0.39, 95CI = [0.25, 0.60]). Interestingly, gilts were likely to spend less time in the open area at nighttime compared to daytime (Odds Ratio = 0.49, 95CI = [0.40, 0.60]), as well as experimental days passed (OR = 0.70, 95CI = [0.66, 0.73]). During the first daytime and nighttime, 1/29 and 2/29 animals preferred the crate respectively, whereas by the last daytime and nighttime 5 and 9 gilts preferred the crate respectively (p < 0.05). While both intrinsic (personality) and extrinsic (time of day, experimental day) factors appear to influence the gilt's housing preferences, most gilts significantly prefer an open area to a crate when free access is provided between the two. A smaller subpopulation of animals developed a preference for stalls but still utilize both the stall and the pen throughout the day.

Investigating Unused Tools for the Animal Behavioral Diversity Toolkit

Behavioral diversity is a commonly used tool used to quantify the richness and evenness of animal behaviors and assess the effect of variables that may impact an animal's quality of life. The indices used in behavioral diversity research, and the study subjects, have not been formally reviewed. This paper aims to identify which indices are being used in behavioral diversity research, and under which scenarios, and uncover novel indices from other disciplines that could be applied to behavioral diversity. To investigate the techniques and species investigated in behavioral diversity literature, a Web of Science literature search was conducted. Two methods: behavioral richness and the Shannon-Wiener index, were the most frequently used indices, whereas the Behavioral Variability index featured rarely. While a range of species appeared in the behavioral literature, mammals were the most frequently studied Class, whereas amphibians did not feature in any papers. There are several diversity indices which did not feature in behavioral diversity including Simpson's index, and Chao. Such indices could be used to better understand animal behavioral study outputs or be used to estimate the number of 'unobserved' behaviors that an animal may express. Future studies could therefore extend beyond the Shannon-Wiener and richness indices.

Risk Factors for Chronic Stress in Sows Housed in Groups, and Associated Risks of Prenatal Stress in Their Offspring

Chronic stress has a detrimental effect on sow welfare and productivity, as well as on the welfare and resilience of their piglets, mediated prenatally. Despite this, the specific risk factors for chronic stress in pregnant sows are understudied. Group-housed pregnant sows continuously face numerous challenges associated with aspects of the physical (group type and size, flooring, feeding system) and social (stocking density, mixing strategy) environment. There are many well-known potent stressors for pigs that likely contribute to chronic, physiological stress, including overcrowding, hot temperatures, feed restriction, inability to forage, uncomfortable floors, and poor handling. Some of these stressors also contribute to the development of production diseases such as lameness, which in turn are also likely causes of chronic stress because of the associated pain and difficulty accessing resources. The aim of this review is to discuss potential risk factors for chronic stress in pregnant sows such as space allowance, group size and type (stable/dynamic), feeding level, lameness, pen design, feed system, enrichment and rooting material, floor type, the quality of stockmanship, environmental conditions, and individual sow factors. The mechanisms of action of both chronic and prenatal stress, as well as the effects of the latter on offspring are also discussed. Gaps in existing research and recommendations for future work are outlined.

The Behaviour and Productivity of Mid-Lactation Dairy Cows Provided Daily Pasture Allowance over 2 or 7 Intensively Grazed Strips

Research into the effects of intense grazing regimes on cattle behaviour and productivity will support the ethical intensification of pastoral dairy production. Two treatments were applied to two herds of 30 mid-lactation cows over 28 days. Cows were offered an estimated 12 kg DM/cow (above 5 cm from ground level) of irrigated pasture per day. The control herd received their daily pasture allocation in two equal grazings while the experimental herd received theirs over seven smaller grazings. Backgrazing beyond the current allocation (morning or afternoon) was prevented. Individual records were taken daily for milk production and behaviour (MooMonitor⁺). Milk composition, energy corrected milk (ECM), and live weight were recorded weekly. Feeding mid-lactation dairy cows over seven smaller grazing allocations reduced the time cows spent ruminating (p < 0.001), milk yield (p < 0.001), and ECM (p < 0.05). However, milk composition, live weight, time feeding, and pasture consumption were not affected by feeding frequency (p > 0.05). Cattle may have adapted their ingestive behaviour in response to the more intensive strip-grazing regime utilised in this study, with negative consequences for digestive processes and consequently milk production. Intense grazing regimes need to support the ingestive, digestive, and social behaviours of cattle.

Sow housing associated with reproductive performance in breeding herds

Female pigs in breeding herds can be managed through four phases-gilt development, breeding, gestation, and lactation-during which they may be housed in group or individual pens, stalls, or on pasture. In this review, we focus on housing environments that optimize outcomes during gestation and lactation. Appropriate housing is important during early gestation, to protect embryos and to confirm pregnancy, and from mid-to-late gestation, to ensure sufficient nutrition to increase placental and fetal growth. No difference in the number of pigs born alive were reported between group housing and individual stall housing, although more risk factors for reproductive performance are associated with group housing than stall housing including genetics, bedding, floor space allowance, group size, social ranking, and parity. Furthermore, lameness in pregnant pigs is more frequent in group housing than in stall housing. Housing during lactation helps protect piglets from being crushed or from contracting disease, and can foster the transfer of enough colostrum from mother to piglets. Indeed, lactating sows in pen housing tend to have higher pre-weaning mortality and lighter litter weights than those in crated housing.

Social interaction patterns according to stocking density and time post-mixing in group-housed gestating sows

Housing systems should enable animals to interact socially while minimising aggression. This study investigated whether social interaction patterns in groups of indoor-housed gestating sows are affected by stocking density (‘SD’), by varying the number of sows per pen, and day after mixing. Unacquainted sows were grouped within 5 days of insemination at 1.45 (High; ‘H-SD’), 2.0 (Moderate; ‘M-SD’) or 2.9 m2 per sow (Low; ‘L-SD’) by placing 20, 14 or 10 sows per pen. Five pens per treatment were represented, and within each pen, 10 focal sows were observed. Social behaviours between focal sows were analysed continuously for 15 min after drop-feeding the day after mixing (Day 2) and 1 week later (Day 9), and plasma cortisol and progesterone concentrations analysed on Days 2 and 26. Overall, 587 interactions were observed, with 59% being short one reciprocal actions. Sows used more physical aggression at H-SD on Day 2 such as bites (vs M-SD and L-SD: both P < 0.01), head knocks and pushes (vs L-SD: P = 0.01; vs M-SD: P = 0.06), whereas social interactions at lower SD were more frequent (L-SD vs H-SD: P = 0.004; L-SD vs M-SD: P = 0.02) and contained presumably neutral social behaviours such as nose contacts (L-SD vs H-SD: P = 0.06; M-SD vs H-SD: P = 0.07), or non-physical agonistic behaviours such as threats (L-SD vs H-SD: P = 0.07). A first-order Markov transitional analysis revealed positive feedback loops for bites and knocks or pushes at higher SD on Day 2 (all P < 0.05). Cortisol concentration decreased as SD decreased (L-SD vs H-SD: P < 0.001; L-SD vs M-SD: P = 0.02; M-SD vs H-SD: P = 0.07). Hence, interactions were more aggressive and less frequent at higher SD at Day 2 post-mixing, but differences vanished at Day 9. Valuable information can be gained from analysing the type of social behaviours and behavioural sequences, in addition to overall aggression frequency.

Wider stall space affects behavior, lesion scores, and productivity of gestating sows

Limited space allowance within the standard gestation stall is an important welfare concern because it restricts the ability of the sow to make postural adjustments and hinders her ability to perform natural behaviors. Therefore, we evaluated the impacts of increasing stall space and/or providing sows the freedom to access a small pen area on sow well-being using multiple welfare metrics. A total of 96 primi- and multiparous crossbred sows were randomly assigned in groups of 4 sows/treatment across 8 replicates to 1 of 3 stall treatments (TRT): standard stall (CTL; dimensions: 61 by 216 cm), width-adjustable stall (flex stall [FLX]; dimensions: adjustable width of 56 to 79 cm by 216 cm), or an individual walk-in/lock-in stall with access to a small communal open-pen area at the rear of the stall (free-access stall [FAS]; dimensions: 69 by 226 cm). Lesion scores, behavior, and immune and productivity traits were measured at various gestational days throughout the study. Total lesion scores were greatest for sows in FAS and least for sows in FLX ( < 0.001). Higher-parity sows in FAS had the most severe lesion scores (TRT × parity, < 0.0001) and scores were greatest at all gestational days (TRT × day, < 0.05). Regardless of parity, sows in FLX had the least severe scores ( < 0.0001). As pregnancy progressed, lesion scores increased among sows in CTL ( < 0.05). Sow BW and backfat (BF) were greater for sows in FLX and FAS ( < 0.05), and BCS and BF were greater for parity 1 and 2 sows in FAS than the same parity sows in CTL (TRT × parity, < 0.05). Duration and frequency of some postural behaviors and sham chew behavior were affected by TRT ( < 0.05) and time of day (TRT × day, < 0.05). These data indicate that adequate stall space, especially late in gestation, may improve the well-being of higher-parity and heavier-bodied gestating sows as assessed by changes in postural behaviors, lesion severity scores, and other sow traits. Moreover, compromised welfare measures found among sows in various stall environments may be partly attributed to the specific constraints of each stall system such as restricted stall space in CTL, insufficient floor space in the open-pen area of the FAS system, and gate design of the FLX (e.g., direction of bars and feeder space). These results also indicate that parity and gestational day are additional factors that may exacerbate the effects of restricted stall space or insufficient pen space, further compromising sow well-being.