Improving young pig welfare on-farm: The Five Domains Model.

Considering welfare through the "neonatal and nursery pig perspective" is an exciting approach and one that resonates with consumers. Overlaying this with the Five Domains Model, as we suggest in this review, points to practical on-farm improvements that provide each pig the opportunity to experience positive mental states. The Five Domains Model is broken into physical and functional states, which include Domain 1: Nutrition, Domain 2: Physical Environment, Domain 3: Health, and Domain 4: Behavioral Interaction, and Domain 5: Mental State. The Five Domains Model can build on the breadth and depth of swine welfare science to highlight opportunities to improve welfare on-farm. In Domain 1, management of increasingly large litters is considered, with examples of sow vs. artificial rearing, colostrum quality and quantity, and creep feed management strategies. Efforts can result in positive mental states such as feeling full and content and the ability to experience the pleasure of drinking and food tastes and smells. Domain 2 considers space complexity and access to key resources, along with thermal and physical amenities, to promote feelings of physical comfort. Domain 3 considers pig health in three broads, yet inter-linking categories 1) congenital and hereditary health, 2) environmental pathogen load, and 3) colostrum quality and quantity, and its effect on the microbiome. Improvements can result in a pig that displays vitality and feels healthy. Domain 4 provides the pig opportunities to express its rich behavioral repertoire, specifically positive social interactions, play, and exploration. These efforts can result in pigs feeling calm, safe, comfortable, having companionship, engaged, interested, and rewarded. In conclusion, using the Five Domains Model can highlight numerous opportunities to improve current and future housing and management through the "neonatal and nursery pig perspective" with a focus on inducing positive mental states that can result in improved quality of life and welfare state.

Considering welfare through the "neonatal and nursery pig perspective" is an exciting approach. Overlaying this with the Five Domains Model, as we suggest in this review, points to practical on-farm improvements that provide each pig the opportunity to experience positive mental states. The first four domains consider physical and functional states; with Domains 1 through 4 being Nutrition, Physical Environment, Health, and Behavioral Interaction, respectively. All interweave with Domain 5: Mental state. A plethora of examples are discussed; Domain 1 critiques optimal colostrum intake, and milk and feed quality that result in feelings of fullness and contentment. Domain 2 considers space complexity, key resource access, and thermal and physical amenities with these efforts resulting in feelings of comfort and agency. Domain 3 discusses congenital and hereditary health, environmental pathogen load, colostrum quality and quantity effects on the microbiome, and how these improve pig vitality and feelings of good health and fitness. Domain 4 discusses opportunities for the pig to express its behavioral repertoire, particularly positive social interactions, play, and exploration with feelings of control and agency. Improvements will result in pigs feeling calm, safe, comfortable, enjoying companionship, engaged, interested, and leading a rewarding life.

Rearing in female-only groups and dietary mineral supplementation improves sow welfare in the early parities and lifetime performance.

The lifetime performance of commercial sows relies on longevity, which is dependent on good health and reproductive performance. However, there is a high rate of wastage of sows in the early parities, which is influenced by the way they are managed and housed during rearing. This study investigated the carry-over effect of gilt rearing strategy on the measures of welfare and performance. Eighty sows were reared using a two by two factorial design: rearing group composition [GC; female-only (FEM) or mixed-sex (MIX) from weaning] with or without supplementary minerals (CON = control diet; SUPP = control + Cu, Zn, and Mn) from 5 wk into the finisher stage. Once served, gilts were managed in a dynamic group gestation pen and fed a standard gestating sow diet. Locomotory ability was scored (0 to 5) and salivary cortisol measured five times during the first gestation, and human approach tests were carried out on day 108. Hooves were scored for injuries and legs for bursas at day 70 of the first gestation, at first weaning, and at the second farrowing. Sow behavior in the hoof scoring crate (movement, vocalization, and handling ease) was also recorded. The number of piglets born alive and dead during the first five parities was recorded as was the performance of the first litter to finish. Data were analyzed using general or generalized linear mixed models, as appropriate, using SAS (v 9.4). There was no effect (P > 0.05) of rearing treatment on locomotory ability, bursa score, the total number of piglets born, or on offspring growth. However, there was an interaction between GC and supplementary minerals (P < 0.05) on salivary cortisol levels with MIX × SUPP sows having the highest levels. Total hoof scores and heel erosion scores were higher in sows reared in MIX groups (P < 0.01), and CON sows tended to have higher horizontal crack scores (P = 0.06). Sows from MIX kicked more at weaning than FEM (P < 0.05) and tended to be more fearful in the forced human approach test (P = 0.1) where they are scored on their reaction to being approached. They also had more stillborn piglets across all five parities than FEM (P < 0.05). Overall, rearing replacement sows in FEM groups and dietary mineral supplementation had minimal but beneficial effects on their subsequent welfare and performance.

The effect of group composition and mineral supplementation during rearing on the behavior and welfare of replacement gilts.

Sow longevity supported by good health and reproductive performance is necessary to optimize sow lifetime performance. In some countries, replacement gilts are reared with finisher pigs destined for slaughter, so they are exposed to sexual and aggressive behaviors performed by males. This is associated with stress and injury. Moreover, diets formulated for finishers are not designed to meet the needs of replacement gilts and may not supply the necessary minerals to promote limb health, optimal reproduction, and, thus, sow longevity. In this 2 × 2 factorial design experiment with 384 animals (32 pens [12 animals per pen]), we investigated the effect of female-only (FEM) or mixed-sex (MIX) rearing, with (SUPP) or without (CON) supplementary minerals (copper, zinc, and manganese) on locomotion, salivary cortisol levels, behavior, body lesions (BL), and hoof health of gilts. The experimental period began at transfer to the finisher stage (day 81.3 ± 0.5 of age; day 0) until breeding age (day 196 ± 0.5 of age; day 115). Locomotion was scored (0-5) biweekly from day 0 until slaughter day 67 or breeding age day 115 for the remaining gilts. Saliva samples were taken monthly from four focal gilts per pen. All counts of aggressive, harmful, sexual, and play behavior were recorded by direct observation 1 d biweekly (5- × 5-min observations/pen/d). BL scores were recorded on focal pigs biweekly from day 1 until day 99 on the back, neck, shoulder, flank, and hind quarter on each side of the body. Hind hooves were scored for eight disorders (heel erosion [HE], heel sole separation [HSS], and white line separation [WLS], dew claw length and dew claw cracks, toe length and both vertical and horizontal toe cracks) by severity, and a total hoof lesion score was calculated by summing individual scores. General linear mixed models were used to analyze cortisol, behavior, BL, and total hoof scores. Generalized linear mixed models were used for locomotion, bursitis and individual hoof disorders. There was less aggression (P < 0.05) and sexual behavior in the FEM compared to the MIX groups with more play behavior in MIX compared to FEM groups (P < 0.01). Gilts in the MIX groups had higher BL scores than gilts in the FEM groups (P < 0.001). Total hoof scores were higher in MIX (8.01 ± 0.15) than FEM (7.70 ± 0.12; P < 0.02) gilts. CON diet gilts had higher HE scores than SUPP gilts (P < 0.05). HSS (P < 0.05) and WLS (P < 0.05) scores were higher in MIX than FEM gilts. Rearing gilts in FEM groups had benefits for hoof health likely mediated through lower levels of activity due to male absence, and minerals helped reduce HE.

Effect of increasing dietary energy density during late gestation and lactation on sow performance, piglet vitality, and lifetime growth of offspring.

Genetic selection for hyperprolificacy in sows has resulted in a significant increase in the number of piglets born alive per litter but subsequently, decreased piglet vitality and growth. As a consequence, increasing sows' energy intake during lactation to help increase piglet vitality and growth is increasingly important. The objective of this study was to investigate the effect of increasing dietary energy density for lactating sows on weight and back-fat changes in sows, milk composition, and vitality and growth of progeny. Gestating sows (N = 100; Large White × Landrace) were randomly assigned to one of four energy dense diets at day 108 of gestation until subsequent service; 13.8 (LL), 14.5 (L), 15.2 (H), and 15.9 MJ DE/kg (HH). All diets contained 1.2% total lysine. Blood samples from sows were taken on day 108 of gestation and at weaning (day 26 of lactation) and colostrum (day 0) and milk samples (day 14) were collected during lactation. Sow lactation feed intakes were recorded daily. The number of piglets born per litter (total and live), piglet birth weight (total and live), intrauterine growth restriction (IUGR) traits and muscle tone were recorded in piglets at birth. Piglet tympanic ear temperature (TEMP) was recorded at birth and at 24 h. Pigs were weighed on days 1, 6, 14, 26, 33, 40, 54, 75, and 141 of life. Postweaning (PW) pigs were fed standard cereal-based diets. Pig carcass data were collected at slaughter (day 141). Lactation energy intake was higher for HH sows than for all other treatments (P < 0.01). Colostrum and milk composition and lactation feed intake were not affected by treatment. The number of piglets born per litter (total and live) and piglet birthweight (total and live) was similar between treatments. Piglets from LL sows had more IUGR traits (P < 0.01), while those from HH sows had better muscle tone (P < 0.01) than all other treatments. Piglets from LL sows (P < 0.01) and piglets from H sows (P < 0.01) had a higher 24 h TEMP than piglets from HH sows. H sows weaned a greater number of piglets than L sows (P < 0.05) and HH sows (P < 0.01), while L sows weaned lighter litters than H (P < 0.05) and LL sows (P < 0.05). Pig growth PW was unaffected by treatment. High energy dense diets increased energy intake in sows, without depressing appetite. Feeding an HH diet improved piglet muscle tone at birth, whereas feeding an H diet increased litter size at weaning. Inconsistent results were observed for other traits of piglet vitality and for preweaning litter growth performance.

The Effect of Group Composition and Mineral Supplementation during Rearing on Measures of Cartilage Condition and Bone Mineral Density in Replacement Gilts.

Lameness is a major cause of poor longevity and poor welfare in replacement gilts. The problem is exacerbated by inappropriate housing and diet during the rearing period. Replacement gilts are often reared with male finisher pigs destined for slaughter. If they are not castrated, they perform high levels of potentially injurious sexual and aggressive behaviour. Furthermore, finisher pig diets are not designed to meet the needs of developing gilts and may not supply the necessary minerals to support good limb health. The objective of this study was to evaluate the effect of supplementing the diet of replacement gilts with copper, zinc and manganese and separating them from males during the rearing period on locomotory ability, bone mineral density and cartilage lesion scores. A 2 × 2 factorial design experiment investigated the effect of female-only or mixed-sex rearing, with or without supplementary minerals (Copper, Zinc and Manganese). In total, 384 maternal line gilts were assigned to 32 pens of 12 and were locomotion scored during the rearing period. A sub-sample (n = 102) of gilts were culled at breeding age and the front right limb was removed at slaughter. Areal bone mineral density (aBMD) was measured using dual energy X-ray absorptiometry, after which the limb was dissected to score the condition of the cartilage. The addition of trace minerals to the diet resulted in increased aBMD in the humerus (P < 0.05) compared to the control diet. Rearing gilts in female-only groups reduced the number of cartilage lesions overall (P < 0.05), and on the humeral condyle (P < 0.05). Rearing replacement gilts in female-only groups and with mineral supplementation had benefits for limb health.

Effect of l-carnitine supplementation and sugar beet pulp inclusion in gilt gestation diets on gilt live weight, lactation feed intake, and offspring growth from birth to slaughter1.

This study evaluated the effects of l-carnitine (CAR) and sugar beet pulp (SBP) inclusion in gilt gestation diets on gilt live weight, cortisol concentration, lactation feed intake, and lifetime growth of progeny. Eighty-four pregnant gilts (Large White × Landrace) were randomly assigned to a treatment at day 38 of gestation until parturition; Control (0% SBP, 0 g CAR), CAR (0.125 g/d CAR), SBP (40% SBP), and SBP plus CAR (40% SBP, 0.125 g/d CAR). Gilts were weighed and back-fat depth was recorded on day 38, day 90, and day 108 of gestation and at weaning. Gilt saliva samples were collected pre-farrowing and fecal consistency was scored from entry to the farrowing room until day 5 post-partum. The number of piglets born (total, live, and stillborn) and individual birth weight was recorded. Piglet blood glucose concentration was measured 24 h post-partum and pigs were weighed on day 1, day 6, day 14, day 26, day 76, day 110, and day 147 of life. Carcass data were collected at slaughter. There was no interaction between CAR and SBP for any variable measured. The SBP-fed gilts were heavier on day 90 and day 108 of gestation (P < 0.05) and lost more weight during lactation (P < 0.05) than control gilts. They also had a greater fecal consistency score (P < 0.01). Total farrowing duration, piglet birth interval, and lactation feed intakes were similar between treatments (P > 0.05). The number of piglets born (total, live, and stillborn) and piglet birth weight was likewise similar between treatments (P > 0.05). Piglets from CAR-fed gilts had lower blood glucose concentrations (P < 0.01), while piglets from SBP-fed gilts had greater blood glucose concentrations (P < 0.01). Piglets from CAR gilts had a lower average daily gain between day 1 and day 6 (P < 0.05) and day 14 and day 26 post-partum (P < 0.05) compared to piglets from control gilts. However, CAR gilts weaned a greater number of pigs (P = 0.07). Live weight and carcass weight at slaughter were heavier for pigs from CAR gilts (P < 0.05) and from SBP gilts (P < 0.05). Pigs from CAR gilts (P < 0.01) and SBP gilts (P < 0.05) had increased carcass muscle depth. In conclusion, no benefit was found from the combined feeding of CAR and SBP. Fed separately, CAR increased the live weight, carcass weight, and muscle depth of progeny at slaughter. Feeding a high SBP diet increased fecal consistency in gilts pre-farrowing and increased live weight and carcass muscle depth of progeny.

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.

The 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.