Effect of leg conformation on survivability of Duroc, Landrace, and Large White sows

The Effects of Mild Disturbances on Sleep Behaviour in Laying Hens

The positive welfare of commercial animals presents many benefits, making the accurate assessment of welfare important. Assessments frequently use behaviour to determine welfare state; however, nighttime behaviours are often ignored. Sleep behaviour may offer new insights into welfare assessments. This study aimed to establish a baseline for sleep behaviour in laying hens and to then apply mild short-term disturbances and observe the subsequent effects. Twelve laying hens were divided into four batches and were surgically implanted with electroencephalogram (EEG) devices to record their brain activity. The batches were subjected to undisturbed, disturbed and recovery types of nights. Disturbed nights consisted of systematic sequences of disturbance application (wind, 90 dB noise or 20 lux light) applied one at a time for 5 min every 30 min from 21:00 to 03:00 (lights off period: 19:00-05:00). Sleep state was scored using EEG data and behaviour data from infrared cameras. Over all the types of night hens engaged in both SWS (58%) and REM sleep (18%) during lights off. When applied, the disturbances were effective at altering the amounts of wakefulness and SWS (Time × Type of Night, p < 0.001, p = 0.017, respectively), whereas REM sleep was unaltered (p = 0.540). There was no evidence of carry-over effects over the following day or night. Laying hens may be resilient to short-term sleep disruption by compensating for this in the same night, suggesting that these disturbances do not impact their long-term welfare (i.e., over days). Sleep behaviour potentially offers a unique means of assessing an aspect of animal welfare that, to date, has been poorly studied.

Evaluating the long-term conformation and hoof growth effects of starting hoof trimming at 5 months of age in New Zealand dairy goats

Hoof overgrowth is associated with poor conformation, an altered weight-bearing surface, and a reduction in the hoof's anatomic and functional integrity. As a result of housing systems that promote hoof overgrowth, hoof trimming is considered a priority in dairy goats. However, there are few data on the effects of the timing of first trimming on hoof conformation and growth rate. The aims of this study were (1) to evaluate the long-term effects of 2 different hoof trimming start times and (2) to investigate the pattern of hoof growth across the first 2 yr of life. Eighty 5-mo-old female Saanen-cross commercially housed dairy goats were allocated randomly to 1 of 2 treatments: (1) early trimmed (trimming beginning at 5 mo old; hooves were trimmed every 4 mo thereafter) and (2) late trimmed (trimming beginning at 13 mo old; hooves were trimmed every 4 mo thereafter). Using a combination of photographs and radiographs, hoof conformation, joint positions, and hoof wall length were assessed before the 13- and 25-mo trimming events. Hoof growth was assessed every 12 wk using caliper measurements. Overall, starting hoof trimming earlier had minor and inconsistent effects. However, detrimental changes in conformation and joint positions occurred between trimming events, particularly in the hind hooves, regardless of trimming treatment. At both assessments, there was a high percentage of overgrown toes and dipped heels, with the hind hooves being more affected compared with the front (overgrown toes at 13 mo, 97.1 vs. 79.1 ± 5.2%; overgrown toes at 25 mo, 91.7 vs. 56.3 ± 6.7%; dipped heels at 13 mo, 98.5 vs. 19.3 ± 5.0%; dipped heels at 25 mo, 88.3 vs. 4.9 ± 4.8%). In addition, at both assessments, the distal interphalangeal joint angle was greater in the hind hooves compared with the front (13 mo, 79.5 vs. 65.2 ± 1.7°; 25 mo, 79.0 vs. 66.7 ± 0.9°), whereas heel angles were less in the hind hooves compared with the front (13 mo, 41.8 vs. 57.1 ± 1.5°; 25 mo, 44.9 vs. 55.9 ± 1.1°). On average, the front hooves grew 4.39 mm/mo and the hind hooves grew 4.20 mm/mo. Early trimming did not have consistent effects on hoof growth rate. Importantly, our results suggest that trimming every 4 mo is not sufficient to prevent hoof overgrowth, the development of poor conformation, and detrimental changes in joint positions, particularly in the hind hooves. Furthermore, the detrimental changes may have masked any long-term treatment effects. Therefore, trimming frequency and age of first trimming should be considered when devising hoof care protocols for dairy goats housed in environments that do not offer opportunities for natural hoof wear.

Lifetime and removal reasons for Pietrain boars in European AI centers: a retrospective analysis

Currently, artificial insemination (AI) is the most common reproductive method used in swine production. The economic profitability of AI centers is closely linked to a boar's retention rate and the purchase of replacement boars. The objectives of this study were to examine data of selection process and lifetime of a total of 6,496 purebred Pietrain AI boars and to analyze the frequency and reasons of removal in eight European countries. Data were obtained from two German boar multiplication farms as well as 53 AI centers from 2018 to 2022. The retention time was analyzed from the selection process until replacement and to the end of the examination, respectively. The selection process of the boars took place at 168 ± 5 (mean ± SD) days of age. For further calculations, the removal reasons were divided into nine groups: breeding (BR), died (DI), euthanasia (EU), health (HE), genetics (GE), low libido (LI), sperm quality (SQ), structure (ST), and other (OT). Overall, 56.1% of the examined boars were removed, with 17.5% being removed within the same year they entered the AI center. The annual removal rate for the 53 AI centers averaged 42.4%. The most frequent removal reason was low SQ (45.1%), followed by genetics (28.6%) and low libido (10.6%). The highest relative frequency of removals was observed for an age of 2 yr (34.0%). The highest removal risk was calculated for boars in Czech AI centers (P < 0.001), while the lowest removal risk occurred in Dutch (P = 0.006) and Portuguese AI centers (P = 0.01). The comparison of removal groups revealed, inter alia, higher body weight at selection process for the BR group (117.9 ± 9.0 kg) and longer quarantine periods for LI group (45.9 ± 17.6 d). Boars in the GE group were characterized by the oldest age at removal (934.0 ± 272.8 d) and longest period of exploitation (672.5 ± 266.8 d). The results could be helpful to detect the most common reasons for production failure of AI Pietrain boars and beneficial for establishing an economical removal policy in AI centers and for improving boar management through problem-based selection in boar multiplication farms.

Cattle and Pigs Are Easy to Move and Handle Will Have Less Preslaughter Stress

Previous research has clearly shown that short-term stresses during the last few minutes before stunning can result in Pale Soft Exudative (PSE) pork in pigs or increased toughness in beef. Electric prods and other aversive handling methods during the last five minutes are associated with poorer meat quality. Handlers are more likely to use aversive methods if livestock constantly stop and are difficult to move into the stun box. Factors both inside and outside the slaughter plant contribute to handling problems. Some in-plant factors are lighting, shadows, seeing motion up ahead, or air movement. Non-slip flooring is also very important for low-stress handling. During the last ten years, there have been increasing problems with on-farm factors that may make animals more difficult to move at the abattoir. Cattle or pigs that are lame or stiff will be more difficult to move and handle. Some of the factors associated with lame cattle are either poor design or lack of adequate bedding in dairy cubicles (free stalls) and housing beef cattle for long periods on concrete floors. Poor leg conformation in both cattle and pigs may also be associated with animals that are reluctant to move. Indiscriminate breeding selection for meat production traits may be related to some of the leg conformation problems. Other on-farm factors that may contribute to handling problems at the abattoir are high doses of beta-agonists or cattle and pigs that have had little contact with people.

Claw Characteristics of Culled Sows from Three Farrow-to-Finish Greek Farms. Part 1: Claw Length Measurements, Lesion Scores and Their Association

The aim of the study was to investigate variations in lengths and lesions in claws of culled sows and to evaluate their association. All four feet of 185 sows from three Greek farrow-to-finish farms (Farm A: 57 sows; Farm B: 64 sows; Farm C: 64 sows) were examined for lesions and their lengths were measured. All claw lengths were lower in sows of farm C compared to those from sows of B and A. Claw lengths in sows of farm B were lower compared to those from A for all lateral toes of front feet and for all medial and four out of three lateral toes of rear feet. Sum of length measurements of the main toes of the front feet (SLF) associated with lesions on sole, white line and heel of front feet, while sum of length measurements of the main toes of the rear feet (SLR) associated with all lesions of the rear feet. The lengths of the main toes were correlated with the length of dew claws on front and rear feet. Overall, sows’ claw lesion severity and claw lengths may differ between farms and frequency of lesions is higher in longer claws.

The Development of a Hoof Conformation Assessment for Use in Dairy Goats

The assessment of hoof conformation is important due to its recognized relationship with the biomechanical functionality of the hoof. Hoof conformation can be assessed using objective measures or subjective scores. However, to date, there are limited data using either method in dairy goats. Therefore, the aims were to (1) develop a reliable method of assessing hoof conformation in dairy goats, and (2) compare two aspects of a subjective assessment against corresponding objective measures as a means of validation. A total of 1035 goats contributed photographs across 16 commercial dairy goat farms. Photographs were taken of the left front and left hind hoof in the lateral and dorsal aspect at five assessments across the goats' first two lactations. Hoof conformation was assessed using five subjective scores (toe length, heel shape, fetlock shape, claw splay, and claw shape) and two objective measures (toe length ratio and claw splay distance). Following the training of two observers, high levels of inter and intra-reliability were achieved for both the subjective scores (>0.8 weighted kappa) and objective measures (>0.8 Lin's concordance correlation coefficient). Two aspects of the subjectively assessed ordinal scores were compared with the objective measures with high levels of accuracy (>0.8). This suggests that the subjective scores may be a suitable alternative to more time-consuming objective measures when assessment is completed using photographs.

Genetic association between sow longevity and social genetic effects on growth in pigs

Objective

Sow longevity is important for efficient and profitable pig farming. Recently, there has been an increasing interest in social genetic effect (SGE) of pigs on stress-tolerance and behavior. The present study aimed to estimate genetic correlations among average daily gain (ADG), stayability (STAY), and number of piglets born alive at the first parity (NBA1) in Korean Yorkshire pigs, using a model including SGE.

Methods

The phenotypic records of ADG and reproductive traits of 33,120 and 11,654 pigs, respectively, were evaluated. The variances and (co) variances of the studied traits were estimated by a multi-trait animal model applying the Bayesian with linear-threshold models using Gibbs sampling.

Results

The direct and SGEs on ADG had a significantly negative (−0.30) and neutral (0.04) genetic relationship with STAY, respectively. In addition, the genetic correlation between the social effects on ADG and NBA1 tended to be positive (0.27), unlike the direct effects (−0.04). The genetic correlation of the total effect on ADG with that of STAY was negative (−0.23) but non-significant, owing to the social effect.

Conclusion

These results suggested that total genetic effect on growth in the SGE model might reduce the negative effect on sow longevity because of the growth potential of pigs. We recommend including social effects as selection criteria in breeding programs to obtain satisfactory genetic changes in both growth and longevity.

Objective evaluation of female feet and leg joint conformation at time of selection and post first parity in swine1

Feet and legs of replacement females were objectively evaluated at selection, i.e., approximately 150 d of age (n = 319) and post first parity, i.e., any time after weaning of first litter and before second parturition (n = 277) to 1) compare feet and leg joint angle ranges between selection and post first parity; 2) identify feet and leg joint angle differences between selection and first 3 wk of second gestation; 3) identify feet and leg joint angle differences between farms and gestation days during second gestation; and 4) obtain genetic variance components for conformation angles for the two time points measured. Angles for carpal joint (knee), metacarpophalangeal joint (front pastern), metatarsophalangeal joint (rear pastern), tarsal joint (hock), and rear stance were measured using image analysis software. Between selection and post first parity, significant differences were observed for all joints measured (P < 0.05). Knee, front and rear pastern angles were less (more flexion), and hock angles were greater (less flexion) as age progressed (P < 0.05), while the rear stance pattern was less (feet further under center) at selection than post first parity (only including measures during first 3 wk of second gestation). Only using post first parity leg conformation information, farm was a significant source of variation for front and rear pasterns and rear stance angle measurements (P < 0.05). Knee angle was less (more flexion; P < 0.05) as gestation age progressed. Heritability estimates were low to moderate (0.04-0.35) for all traits measured across time points. Genetic correlations between the same joints at different time points were high (>0.8) between the front leg joints and low (<0.2) between the rear leg joints. High genetic correlations between time points indicate that the trait can be considered the same at either time point, and low genetic correlations indicate that the trait at different time points should be considered as two separate traits. Minimal change in the front leg suggests conformation traits that remain between selection and post first parity, while larger changes in rear leg indicate that rear leg conformation traits should be evaluated at multiple time periods.

Technical note: PaGELL v.1.5: A flexible parametric program for the Bayesian analysis of longevity data within the context of animal breeding

This technical note presents the program PaGELL v.1.5 (Parametric Genetic Evaluation of Lifespan in Livestock), a flexible software program to analyze (right-censored) longevity data in livestock populations, with a special emphasis on the genetic evaluation of the breeding stock. This software relies on a parametric generalization of the proportional hazard model; more specifically, the baseline hazard function follows a Weibull process and flexibility is gained by including an additional time-dependent effect with the number of change points defined by the user. The program can accommodate 3 different sources of variation (i.e., systematic, permanent environmental, and additive genetic effects) and both fixed and time-dependent patterns (only for systematic and permanent environmental effects). Analyses are performed within a Bayesian context by sampling from the joint posterior distribution of the model, and model fit can be easily determined by the calculation of the deviance information criterion. Although this software has already been used on field data sets, its performance has been double-checked on simulated data set, and results are presented in this technical note. PaGELL v.1.5 was written in Fortran 95 language and, after compiling with the GNU Fortran Compiler v.4.7 and later, it has been tested in Windows, Linux, and MacOS operating systems (both 32- and 64-bit platforms). This program is available at http://www.casellas.info/files/pageII.zip.

Genetic association between leg conformation in young pigs and sow longevity

Longevity is important in pig production with respect to both economic and ethical aspects. Direct selection for longevity might be ineffective because 'true' longevity can only be recorded when a sow has been culled or died. Thus, indirect selection for longevity using information from other traits that can be recorded early in life and are genetically correlated with longevity might be an alternative. Leg conformation has been included in many breeding schemes for a number of years. However, proving that leg conformation traits are good early indicators for longevity still remains. Our aim was to study genetic associations between leg conformation traits of young (5 months; 100 kg) Swedish Yorkshire pigs in nucleus herds and longevity traits of sows in nucleus and multiplier herds. Data included 97 533 animals with information on conformation (Movement and Overall score) recorded at performance testing and 26 962 sows with information on longevity. The longevity traits were as follows: stayability from 1st to 2nd parity, lifetime number of litters and lifetime number of born alive piglets. Genetic analyses were performed with both linear models using REML and linear-threshold models using Bayesian methods. Heritabilities estimated using the Bayesian method were higher than those estimated using REML, ranging from 0.10 to 0.24 and 0.07 to 0.20, respectively. All estimated genetic correlations between conformation and longevity traits were significant and favourable. Heritabilities and genetic correlations between conformation and longevity indicate that selection on leg conformation should improve sow longevity.

Pyrosequencing-based analysis of fecal microbial communities in three purebred pig lines

This study examined the fecal bacterial diversity of 15-week-old pigs from three purebred lines: Duroc, Landrace, and Yorkshire. Taxon-dependent and -independent analyses were performed to evaluate differences in the fecal bacterial communities and to identify bacterial genera that can be used to discriminate breeds, following high-throughput pyrosequencing of 16S rRNA genes. Among the breeds evaluated, Landrace had the most diverse bacterial community composition. Prevotella, Blautia, Oscillibacter, and Clostridium were detected in all samples regardless of breed. On the other hand, Catenibacterium, Blautia, Dialister, and Sphaerochaeta were differentially detected among breeds, as demonstrated by the canonical loading plot. The discriminant analysis of principal components plot also showed clear separation of the three purebred pig lines, with a certain degree of similarity between Landrace and Yorkshire pigs and a distinct separation between Duroc pigs and the other two breeds. Other factors not related to breed, such as season or time of sampling and pen effects, may contribute to shaping the gut microbiota of pigs.

Estimation of genetic parameters for productive life, reproduction, and milk-production traits in US dairy goats

Heritabilities and correlations for milk yield (MY), fat yield (FY), protein yield (PY), combined fat and protein yield (FPY), fat percentage (F%), protein percentage (P%), age at first kidding (AFK), interval between the first and second kidding (KI), and real and functional productive life at 72mo (FPL72) of 33,725 US dairy goats, were estimated using animal models. Productive life was defined as the total days in production until 72mo of age (PL72) for goats having the opportunity to express the trait. Functional productive life was obtained by correcting PL72 for MY, FY, PY, and final type score (FS). Six selection indexes were used, including or excluding PL72, with 6 groups of different economic weights, to estimate the responses to selection considering MY, FY, PY, and PL72 as selection criteria. The main criteria that determined the culling of a goat from the herd were low FS, MY, and FY per lactation. Heritability estimates were 0.22, 0.17, 0.37, 0.37, 0.38, 0.39, 0.54, 0.64, 0.09, and 0.16 for PL72, FPL72, MY, FY, PY, FPY, F%, P%, KI, and AFK, respectively. Most genetic correlations between the evaluated traits and PL72 or FPL72 were positive, except for F% (-0.04 and -0.06, respectively), P% (-0.002 and -0.03, respectively), and AFK (-0.03 and -0.01, respectively). The highest genetic correlations were between FPL72 and MY (0.39) and between PL72 and MY (0.33). Most phenotypic correlations between the traits evaluated and FPL72 and PL72 were positive (>0.23 and >0.26, respectively), except for F% (-0.004 and -0.02, respectively), P% (-0.05 and -0.02), KI (-0.01 and -0.07), and AFK (-0.08 and -0.08). The direct selection for PL72 increased it by 102.28d per generation. The use of MY, FY, PY, KI, or AFK as selection criteria increased PL72 by 39.21, 27.33, 35.90, -8.28, or 2.77d per generation, respectively. The inclusion of PL72 as selection criterion increased the expected response per generation from 0.15 to 17.35% in all selection indices studied.

Relationships between longevity, lifetime productivity, carcass traits and conformation in Polish maternal pig breeds

The objective of this study was to obtain heritability estimates for longevity (length of life, length of productive life, number of litters) and lifetime productivity traits (lifetime pig production, lifetime pig efficiency, lifetime litter efficiency) and genetic correlation between them and litter size at first farrowing, growth (ADG), backfat thickness (BF), loin depth, lean meat percentage (LMP), phenotypic selection index (PSI), and exterior in 19423 Polish Landrace (L) and 16049 Polish Large White (LW) sows. Heritabilities for longevity and lifetime productivity traits were 0.10-0.13 for L sows and 0.09-0.11 for LW sows depending on the trait definition. The genetic correlations among these traits were all high and positive, ranging from 0.76 to 0.99. Antagonistic genetic correlations (-0.21 to -0.26) were found between longevity traits and PSI and LMP in LW sows, while in L sows the respective parameters were lower and not significant for length of productive life. The number of live-born piglets in the first litter was positively correlated with lifetime pig production and lifetime pig efficiency in both breeds. The genetic correlations of longevity and lifetime pig production with ADG, BF, loin depth and exterior were small, and in most cases, not significant.

Competing risk analyses of longevity in Duroc sows with a special emphasis on leg conformation

A competing risk approach was used to evaluate the influence of several factors on culling risk for 587 Duroc sows. Three different analyses were performed according to whether sow failure was due to death during productive life (DE) or to one of two causes for voluntary culling: low productivity (LP) and low fertility (LF). Sow survival was analyzed by the Cox model. Year at first farrowing (batch effect) significantly affected sow survival in all three analyses (P < 0.05 for DE and P < 0.001 for LP and LF) whereas farm of origin accounted for relevant variation in the LP and LF analyses. LP culling increased with backfat thickness of more than 19 mm at the end of the growth period (P < 0.05), bad teat condition (P < 0.05) and reduced piglets born alive (P < 0.001). For the LF competing risk analysis, culling increased with age at first farrowing (P < 0.1). Special emphasis was placed on the influence of leg and teat conformation on sow survivability, although they did not affect sow failure due to DE (P > 0.1). The overall leg-conformation score significantly influenced sow longevity in LP (P < 0.001) and LF competing risk analyses (P < 0.001), showing a higher hazard ratio (HR) for poorly conformed sows (1.013 and 4.366, respectively) than for well-conformed sows (0.342 and 0.246, respectively). Survival decreased with the presence of abnormal hoof growth in LP and LF analyses (HR = 3.372 and 6.002, respectively; P < 0.001) and bumps or injuries to legs (HR = 4.172 and 5.839, respectively; P < 0.01). Plantigradism reduced sow survival in the LP analysis (P < 0.05), while sickle-hooked leg (P < 0.05) impaired sow survival in the fertility-specific analysis. Estimates of heritability for longevity related to LP culling ranged from 0.008 to 0.024 depending on the estimation procedure, whereas heritability values increased to between 0.017 and 0.083 in LF analysis. These analyses highlighted substantial discrepancies in the sources of variation and genetic background of sow longevity depending on the cause of failure. The estimated heritabilities suggested that direct genetic improvement for sow longevity seemed feasible, although only a small genetic progress was expected.

Association and expression study of MMP3, TGFβ1 and COL10A1 as candidate genes for leg weakness-related traits in pigs

The present study was aimed to determine the association between metalloproteinase 3 (MMP3), transforming growth factor beta 1 (TGFβ1) and collagen type X alpha I (COL10A1) gene polymorphisms with traits related to leg weakness in pigs. Three hundred Duroc × Pietrain cross breds (DuPi) and 299 pigs of a commercial population (CP) were used for the experiment. DuPi animals were examined for 10 different traits describing leg and feet structure, osteochondrosis (OC) scores and bone density status. Data of OC score at condylus medialis humeri, condylus medialis femoris and distal epiphysis ulna regions of CP were used for association analysis. Significant association (P < 0.05) was found for MMP3 SNP (g.158 C>T) with OC at head of femur and bone mineral density in the DuPi population. Association (P < 0.05) was found between SNP of TGFβ1 (g.180 G>A) with rear leg score and the principle component denoting both OC and feet and leg scores in the DuPi population. No association was found between COL10A1 (g.72 C>T) and leg weakness related traits. The associations of SNPs with OC traits could not be confirmed in the commercial population. Expression analysis of the three candidate genes was performed to compare between healthy and OC. TGFβ1 was found to be highly expressed (P < 0.05) in the OC compared to healthy cartilages, but no significant different expressions were observed for MMP3 and COL10A1 genes. The present finding suggested that TGFβ1 and MMP3 genes variants have an effect on some of the leg weakness related traits.

Genetic background and phenotypic characterization over two farrowings of leg conformation defects in Landrace and Large White sows

A Bayesian threshold animal model was applied to evaluate the prevalence over 2 farrowings and genetic background of overall leg conformation score and the presence or absence of 6 specific leg defects (abnormal hoof growth, splay footed, plantigradism, straight pasterns, sickle-hocked legs, and the presence of swelling or injuries) in purebred Landrace and Large White sows. Data sets contained phenotypic records from 2,477 and 1,550 Landrace and Large White females, respectively, at the end of the growing period. Leg conformation data from first and second farrowings were available for 223 and 191 Landrace sows and 213 and 193 Large White sows, respectively. Overall leg conformation deteriorated with age, with statistically relevant differences between females at the end of the growing period, first farrowing (FF), and second farrowing (SF). In a similar way, the prevalence of the 6 specific leg defects increased between the end of the growing period and FF (with the exception of straight pasterns in the Landrace population). Differences between FF and second farrowing were statistically relevant for hoof growth (highest posterior density regions at 95% did not overlap), plantigradism, sickle-hocked legs, and overall leg conformation score in Landrace and for sickle-hocked leg and overall leg conformation score in Large White. The statistical relevance of the genetic background was tested through the Bayes factor (BF) between the model with the additive genetic component and the model with 0 heritability (nonheritable). Heritability (h(2)) was discarded (BF < 1) for sickle-hocked leg in both breeds, whereas decisive evidence (BF > 100) of genetic background was obtained for overall leg conformation score in Landrace and Large White sows (h(2) = 0.27 and 0.38, respectively), hoof growth in both breeds (h(2) = 0.22 and 0.26, respectively), and plantigradism (h(2) = 0.34) and the presence of swelling or injuries in Landrace (h(2) = 0.27). Note that a BF > 100 implies that the model with infinitesimal genetic effects was more than 100 times more suitable than the model without genetic effects, a conclusive estimate within the Bayesian framework. The remaining traits (splay footed and straight pasterns) registered BF values ranging from 11.6 to 35.1 and h(2) values ranging from 0.09 to 0.19. These results indicated a moderate genetic determinism for leg conformation in Landrace and Large White sows.

Skew distribution of founder-specific inbreeding depression effects on the longevity of Landrace sows

Inbreeding is a biological phenomenon of special relevance in domestic species in which its influence has been typically associated with reductions in animal fitness. Nevertheless, recent research suggests substantial founder-specific variability in terms of inbreeding depression on some productive traits, although this centred on a very reduced number of founders. This research focuses on the modelling of founder-specific inbreeding depression (FSID) effects from a more general point of view, characterizing the expected distribution of FSID effects on sow longevity. Under a change-point Weibull proportional hazards model solved through Bayesian inference, a skew-normala prioridistribution for the FSID effects of 19 founders was assumed. In terms of the deviance information criterion, this model was clearly preferred to other prior distributions for FSID effects as well as to a standard analysis of the overall inbreeding depression effect, although all models were consistent with an overall negative genetic effect of inbreeding on sow longevity. The joint posterior distribution of FSID effects showed a skewed pattern with substantial right-tail overexpression, in which the mean (0·036), mode (0·034), S.D. (0·032) and asymmetry parameter (0·045) reported a higher incidence of positive estimates (85·2%) with an unfavourable effect on sow longevity. The founder with the worst inbreeding depression effect reduced sow longevity by 32 days for 1% or 167 days for 10% partial inbreeding. As a whole, our analyses highlighted substantial variability in FSID effects, with unfavourable, neutral and even favourable influences on sow longevity. This heterogeneity could be related to an uneven distribution of the recessive deleterious genetic load among founder genomes, and also with the different selection pressures applied to each founder line. The implementation of skew-normal priors also proved an appealing way to bypass the strict scenario imposed by the standard symmetric-Gaussian distribution, allowing right- and left-tail overexpression as well as non-zero modal estimates.