Number Of Piglets Born Alive Research Articles

PSVI-2 Rising 10-year Trend in Piglet Pre-weaning Mortality in Breeding Herds Associated with Sow Herd Size and Number of Piglets Born Alive

Abstract The objectives of the present study were to explore the trend in preweaning mortality (PWM) and related measurements such as piglets born alive (PBA), stillborn piglets, herd productivity and herd size in sow herds over a 10-year period; and 2) to examine the relationships between PWM and the related measurements. Herd-level annual data from 2007–2016 for 91 herds in Spain were abstracted from a sow database compiled by a veterinary consultancy firm. The database software automatically calculated herd-level PWM (%) as follows: the total number of piglets born alive to a sow completely weaned during a year (TPBA) minus the total number of piglets weaned by the completely weaned sow during the year divided by TPBA x 100. All the statistical analyses were performed using SAS University Edition. A growth curve model was applied to incorporate correlations for all of the observations arising from the same farm. Herd means of PWM (SD) increased from 11.9 (4.1) % to 14.4 (3.2) %, and mean PBA increased by 1.9 pigs. Mean age of piglet death during lactation increased by 3.8 days, and there was a significant effect of increased year on herd size and the number of piglets weaned per sow per year (PSY; P < 0.05). Higher PWM was associated with more PBA, more stillborn piglets and small herds (lower than the median size: < 570 sows; P < 0.05). Also, as PBA increased from 9 to 14 pigs, PWM in large herds (> 570 sows) increased by only 6.6%, compared with 9.6% in small herds. Furthermore, as PWM decreased from 18 to 8%, herd productivity measured as PSY increased by 2.2 pigs in large herds, but only by 0.6 pigs in small herds. In conclusion, the effect of increased PBA on PWM was alleviated more in large herds than in small herds. Also, the impact of decreased PWM on herd productivity was greater in large herds than in small herds.

Genetic Analysis of Major Production and Reproduction Traits of Korean Duroc, Landrace and Yorkshire Pigs.

Simple SummaryKorean purebred pigs are generally selected according to their production and reproduction traits in order to optimize commercial pig performance. It is, therefore, crucial to assess the genetic parameters of these traits to understand their genetic potential. For this reason, we analyzed three production traits (average daily gain, ADG; days to 105 kg weight, DAYS105; backfat thickness, BFT) and three reproduction traits (age at first farrowing, AFF; total number of piglets born, TNB; total number born alive, NBA) in Korean Duroc, Landrace and Yorkshire pigs using animal models. We found that production traits were moderately to highly heritable, whereas reproduction traits were mostly lowly heritable. Evidence of selection improvement of DAYS105 and ADG without increasing BFT was also available. Genetically, NBA and TNB were positively and tightly linked, which further pointed to the need for careful breeding plans that consider the negative impact of higher TNB over NBA on piglets’ mortality. Furthermore, AFF needs systematic attention in relation to genetic progress. Overall, most of our estimates suggested further improvement possibilities through selection. We argue that current genetic parameters could greatly assist future breeding and selection decisions for performance improvements in Korean pigs for specific purposes.The study aimed to investigate the genetic parameters of the production and reproduction traits of Korean Duroc, Landrace, and Yorkshire pigs. Three production traits, namely average daily gain (ADG), age at 105 kg body weight (DAYS105) and backfat thickness (BFT), and three reproduction traits, namely age at first farrowing (AFF), total number of piglets born (TNB) and number of piglets born alive (NBA), were analyzed. The reproduction dataset was based on first-parity gilts only. However, the production dataset comprised pigs of both sexes. Genetic parameters were estimated from individual datasets using a multiple-trait animal model in AIREMLF90 software. The heritability values of ADG, DAYS105 and BFT were 0.34–0.36, 0.41–0.44 and 0.38–0.48, respectively, across breeds. Heritability values for AFF, TNB and NBA were 0.07–0.14, 0.09–0.11 and 0.09–0.10, respectively. Strong genetic correlations existed between ADG and DAYS105 (−0.97) and between TNB and NBA (0.90 to 0.96). In line with breeding goals, all productive traits in Duroc pigs, and all reproduction traits except AFF in Landrace and Yorkshire pigs, also showed noticeable improvements in recent years. In conclusion, we believe that our findings on economic traits would greatly assist future pig breeding decisions in Korea.

The Association of an SNP in the EXOC4 Gene and Reproductive Traits Suggests Its Use as a Breeding Marker in Pigs.

Simple SummaryThe exocyst complex component 4 (EXOC4) gene is essential for the growth and development of humans and animals. However, the molecular mechanisms between EXOC4 and the reproductive performance of pigs is yet to be elucidated. The findings of our study revealed that single-nucleotide polymorphism (SNP) rs81471943 (C/T) was located in the EXOC4 gene by Sanger sequencing and PCR-restriction fragment length polymorphism (PCR-RFLP). We then analyzed the relationship between this SNP in EXOC4 and reproductive traits. We found that CC was the most frequent genotype on number of piglets born alive (NBA), litter weight at birth (LWB), number of piglets weaned (NW), and litter weight at weaning (LWW). Finally, 5′-deletion and luciferase assays showed a positive transcription regulatory element in the EXOC4 promoter. Therefore, we predicted that −1781G/A might regulate the expression of EXOC4 by affecting the potential binding of transcription factors P53, E26 transformation specific sequence -like 1 transcription factor (ELK1), or myeloid zinc finger 1 (MZF1).In mammals, the exocyst complex component 4 (EXOC4) gene has often been reported to be involved in vesicle transport. The SNP rs81471943 (C/T) is located in the intron of porcine EXOC4, while six quantitative trait loci (QTL) within 5–10 Mb around EXOC4 are associated with ovary weight, teat number, total offspring born alive, and corpus luteum number. However, the molecular mechanisms between EXOC4 and the reproductive performance of pigs remains to be elucidated. In this study, rs81471943 was genotyped from a total of 994 Duroc sows, and the genotype and allele frequency of SNP rs81471943 (C/T) were statistically analyzed. Then, the associations between SNP rs81471943 and four reproductive traits, including number of piglets born alive (NBA), litter weight at birth (LWB), number of piglets weaned (NW), and litter weight at weaning (LWW), were determined. Sanger sequencing and PCR restriction fragment length polymorphism (PCR-RFLP) were utilized to identify the rs81471943 genotype. We found that the genotype frequency of CC was significantly higher than that of CT and TT, and CC was the most frequent genotype for NBA, LWB, NW, and LWW. Moreover, 5′-deletion and luciferase assays identified a positive transcription regulatory element in the EXOC4 promoter. After exploring the EXOC4 promoter, SNP −1781G/A linked with SNP rs81471943 (C/T) were identified by analysis of the transcription activity of the haplotypes, and SNP −1781 G/A may influence the potential binding of P53, E26 transformation specific sequence -like 1 transcription factor (ELK1), and myeloid zinc finger 1 (MZF1). These findings provide useful information for identifying a molecular marker of EXOC4-assisted selection in pig breeding.

Index selection as a key in the selection process for pigs

Submitted 2020-06-30 | Accepted 2020-08-09 | Available 2020-12-01 https://doi.org/10.15414/afz.2020.23.mi-fpap.74-78 Farrowing records of the Duroc, Hampshire and Pietrain breed were analysed by means of a three-trait repeatability animal model. The examined traits were number of piglets born alive (NBA), number of weaned piglets (NWE) and litter weight at weaning (LWWE). Heritability estimates were 0.10, 0.08 and 0.12 for NBA, NWE and LWWE, respectively. The ratios of the permanent environmental variance to the phenotypic variance were 0.08, 0.05 and 0.03 for NBA, NWE and LWWE, respectively. Using the estimated breeding values a desired index was constructed in order to improve each trait by one additive genetic standard deviation. NWE and NBA have a high correlation and range within breeds from 0.87 to 0.91, but LWWE had poor to moderate correlation with NBA and NWE (0.13 to 0.59). Animals ranking based on index showed better genetic merit for Duroc breed and the index scores ranged from 49.77 to 186.56. In the case of Hampshire and Pietrain breeds somewhat lower index scores (30.92 to 165.97) were observed. The estimated genetic trend for NBA was highest for the Pietrain breed (0.02), but for Duroc and Hampshire breeds the estimates were zero and negative (-0.01). For NWE the estimated genetic trends were practically zero for Duroc and Pietrain breeds and it was 0.02 for Pietrain. LWWE showed highest genetic trend for Duroc breed (0.17) but it was lower (0.09) for Pietrain and and negative (-0.24) for Hampshire. Keywords: pig, selection, breeding value, desired gain index, aggregate genotype References Brascamp E.W. (1984). Selection indices with constraints. Animal Breeding Abstracts 52, 645-654. Groeneveld E, Kovac M, Mielenz N. (2008). VCE User’s guide and reference manual. Version 6.0. Neustadt, Germany: Institute of Farm Genetics; p. 1–125. Groeneveld E. (1990). PEST Users’ manual. Institute of animal husbandry and animal behaviour Neustadt: Federal Research Centre. Hamann, H., Steinheuer, R., & Distl, O. (2004). Estimation of genetic parameters for litter size as a sow and boar trait in German herdbook Landrace and Pietrain swine. Livestock Production Science, 85(2-3), 201-207. https://doi.org/10.1016/s0301-6226(03)00135-0 Hungarian Pig Breeders Association (2017). Pig performance testing code. Budapest, 1-39. Chen, P., Baas, T. J., Mabry, J. W., Koehler, K. J., & Dekkers, J. C. M. (2003). Genetic parameters and trends for litter traits in US Yorkshire, Duroc, Hampshire, and Landrace pigs. Journal of animal science, 81(1), 46-53. https://doi.org/10.2527/2003.81146x Irgang, R., Favero, J. A., & Kennedy, B. W. (1994). Genetic parameters for litter size of different parities in Duroc, Landrace, and Large White sows. Journal of Animal Science, 72(9), 2237-2246. https://doi.org/10.2527/1994.7292237x Nagy, I. (2017). Quantitative genetic studies in multiparous species. DSc. Thesis. 1-150. Nath, M., Singh, B.P., Kataria, M.C. Singh, R.V. (2002). MIX: A software for construction of multi-trait selection index. In: Proc. of the 7th World’s Congress on Genetics Applied to Livestock Production. August 19–23, 2002, Montpellier, France. Skorupski, M. T., Garrick, D. J., & Blair, H. T. (1996). Estimates of genetic parameters for production and reproduction traits in three breeds of pigs. New Zealand Journal of Agricultural Research, 39(3), 387-395. https://doi.org/10.1080/00288233.1996.9513198 Â

PSV-15 Genomic basis of reproductive performance in PRRSV-infected sows

Abstract Previous studies have shown that reproductive traits in sows during porcine reproductive and respiratory syndrome (PRRS) outbreaks are lowly heritable. However, little is known about the genomic basis of reproductive performance in PRRS virus (PRRSV)-infected sows. Thus, the objective of this work was to evaluate the genomic basis of reproductive performance in PRRSV-infected sows. Farrowing data from 475 Duroc and 405 Landrace sows that experienced a PRRS outbreak were used. Heritability and genome-wide association studies (GWAS) based on ~30K SNP genotypes were performed for each breed separately, for number of piglets born alive (NBA), stillborn piglets (NSB), mummified piglets (NM), piglets born dead (NBD; NSB+NM), total number of piglets born (TNB; NBA+NBD), and piglets weaned (NW). Heritabilities were estimated with ASReml using a model with the fixed-effect of parity and an animal random-effect, using a genomic-relationship matrix. GWAS was performed using Bayes-B in GenSel with a model fitting parity as fixed-effect and SNP effects as random. Heritability estimates (± standard error) for NBA, NSB, NM, NBD, TNB, and NW were 0.07±0.07, 0.02±0.11, 0.04±0.10, 0.08±0.08, 0.08±0.07, 0.06±0.04, respectively, for Duroc, and 0.09±0.07, 0.10±0.07, 0.10±0.08, 0.11±0.07, 0.07±0.08, 0.07±0.08, respectively, for Landrace. For Duroc, GWAS identified a quantitative trait locus (QTL) on chromosome (chr) 3 [114-120 megabases (Mb)] explaining 3.9% of the genetic variance (GV) for NBA, on chr 13 (189-193 Mb) explaining 2.7% GV for NBD, and on chr 5 (36-41 Mb) explaining 4.3% GV for TNB. For Landrace, GWAS identified a QTL on chr 13 (154-162 Mb) explaining 12.8% GV for NBA, on chr 14 (59-69 Mb) explaining 2.5% GV for NBD, and on chr 10 (7-9 Mb) explaining 4.1% GV for NW. These results indicate that reproductive traits are lowly heritable during a PRRS outbreak with few QTL identified in Duroc and Landrace sows.

PSV-11 Accuracies of genomic prediction for reproductive traits in PRRSV-infected sows

Abstract Recent studies on host-genetics of response to porcine reproductive and respiratory syndrome virus (PRRSV) infection have shown that genetic markers can be used to predict performance in growing pigs. On the other hand, no work has been done on the genomic prediction of reproductive performance in PRRSV-infected sows. Thus, the objective of this work was to assess the accuracies of genomic prediction for reproductive traits in PRRSV-infected sows. A total of 475 Duroc and 405 Landrace sows with ~30K SNP genotypes had farrowing performance data during the outbreak on: number of piglets born alive (NBA), stillborn piglets (NSB), mummified piglets (NM), piglets born dead (NBD; NSB+NM), total number of piglets born (TNB; NBA+NBD), and piglets weaned (NW). Genomic prediction was performed by Bayes-B with a model fitting parity as fixed-effect and SNP effects as random. Analyses were performed for two scenarios: within-breed and between-breed. For the within-breed prediction, 4-fold cross-validation was used. For the between-breed prediction, all data for each breed were used. Accuracy of genomic prediction (AGP) was calculated as the correlation between genomic estimated breeding values and pre-adjusted phenotype, divided by square-root of heritability. For the within-breed prediction, AGP (± standard deviation) for NBA, NBD, NM, NSB, NW, and TNB were 0.24±0.05, 0.07±0.10, -0.27±0.06, -0.24±0.09, -0.05±0.05, 0.19±0.03, respectively, for Duroc, and 0.37±0.02, 0.38±0.11, 0.30±0.07, 0.60±0.10, 0.09±0.11, 0.15±0.10, respectively, for Landrace. For the between-breed prediction, AGP for NBA, NBD, NM, NSB, NW, and TB were 0.28, -0.17, -0.01, 0.37, 0.27, and 0.29, respectively, when training on Landrace and validating on Duroc, and 0.28, -0.14, 0.01, 0.15, 0.23, and -0.01, respectively, when training on Duroc and validating on Landrace. Results show that the accuracies of genomic prediction for reproductive traits during a PRRSV outbreak are low to moderate.

Effect of RNF4-SacII gene polymorphism on reproductive traits of Landrace × Large White crossbred sows.

The aim of the present study was to investigate whether and to what extent the RNF4-SacII gene polymorphism influences reproduction performances in hyperprolific sow lines. The study involved 101 Landrace x Large White crossbred sows, with 461 records collected on the following reproductive traits: Total Number of piglets Born per litter (TNB), Number of piglets Born Alive per litter (NBA), Number of StillBorn piglets per litter (NSB), piglet Pre-Weaning Mortality (PWM) and Number of piglets at Weaning per litter (NW). The least square method with the GLM procedure in SAS with eight effects was used to pursue the data analysis. Study results revealed that TT homozygotes and TC heterozygotes had a significantly higher (p<.05) NW than CC homozygotes for the life-span performance in all parities and first parity analysed. In the fourth parity analysed, TNB and NBA in TC genotype were significantly higher (p<.05) as compared with TT genotype. Based on the life-span performance, significant effect (p<.05) was recorded for order of parity on TNB, NBA and NW, for farrowing season on TNB and NSB, and for lactation length on PWM. In the second parity, significant effect (p<.05) was recorded for sire of boar on NSB and for gestation length on TNB. Only in the fourth parity, significant effect (p<.05) of RNF4 gene was observed on NBA. There was significant additive effect (p<.05) of the RNF4 gene polymorphism identified on NW in all parities analysed, and significant additive and dominance effects (p<.05) on NSB in the third parity analysed. In conclusion, additional research on related production pig genotypes is necessary to elucidate the effect of RNF4 gene mutation on reproductive traits.

Genomics of Heat Tolerance in Reproductive Performance Investigated in Four Independent Maternal Lines of Pigs.

Improving swine climatic resilience through genomic selection has the potential to minimize welfare issues and increase the industry profitability. The main objective of this study was to investigate the genetic and genomic determinism of tolerance to heat stress in four independent purebred populations of swine. Three female reproductive traits were investigated: total number of piglets born (TNB), number of piglets born alive (NBA) and average birth weight (ABW). More than 80,000 phenotypic and 12,000 genotyped individuals were included in this study. Genomic random-regression models were fitted regressing the phenotypes of interest on a set of 95 environmental covariates extracted from public weather station records. The models yielded estimates of (genomic) reactions norms for individual pigs, as indicator of heat tolerance. Heat tolerance is a heritable trait, although the heritabilities are larger under comfortable than heat-stress conditions (larger than 0.05 vs. 0.02 for TNB; 0.10 vs. 0.05 for NBA; larger than 0.20 vs. 0.10 for ABW). TNB showed the lowest genetic correlation (-38%) between divergent climatic conditions, being the trait with the strongest impact of genotype by environment interaction, while NBA and ABW showed values slightly negative or equal to zero reporting a milder impact of the genotype by environment interaction. After estimating genetic parameters, a genome-wide association study was performed based on the single-step GBLUP method. Heat tolerance was observed to be a highly polygenic trait. Multiple and non-overlapping genomic regions were identified for each trait based on the genomic breeding values for reproductive performance under comfortable or heat stress conditions. Relevant regions were found on chromosomes (SSC) 1, 3, 5, 6, 9, 11, and 12, although there were important regions across all autosomal chromosomes. The genomic region located on SSC9 appears to be of particular interest since it was identified for two traits (TNB and NBA) and in two independent populations. Heat tolerance based on reproductive performance indicators is a heritable trait and genetic progress for heat tolerance can be achieved through genetic or genomic selection. Various genomic regions and candidate genes with important biological functions were identified, which will be of great value for future functional genomic studies.

Genetic study of litter size and litter uniformity in Landrace pigs

ABSTRACT We aimed to estimate litter size and litter uniformity genetic parameters and genetic trends of Landrace pigs at birth and at three weeks by using multitrait analyses for 2,787 litters. The following litter traits were evaluated: number of piglets born alive (NBA), within-litter weight mean at birth (MBW), within-litter weight standard deviation at birth (SDB), within-litter weight coefficient of variation at birth (CVB), number of piglets at three weeks (NT), within-litter weight mean at three weeks (MT), within-litter weight [...]

Effect of parity number, year and season farrowing on reproductive performance in Large White pigs

This study examines certain identifiable non-genetic sources of variation (parity number, year and season farrowing) for their effects on Large White sow litter performance traits, such as litter size, mortality and weight of piglets at birth and at weaning. The population used for the present study is from a pig farm managed by Tavriys’ki svyni, LLC, located in Skadovsky district (Kherson Oblast, Ukraine). Reproductive performance records on 280 Large White (LW) sows were used. A total of 633 litters were farrowed from January 2007 to July 2017. The litter records included information on the total number of piglets born (TNB), number of piglets born alive (NBA), number of stillborn piglets (NSB), frequency of stillborn piglets (FSB), average weight of piglets at birth (AWPB), litter size at weaning (NW), piglet pre-weaning mortality (PWM) and average weight of piglets at weaning (AWPW). To determine the effect of parity number, year and month farrowing on reproductive performance traits, the analysis of variance (ANOVA) was used. Results obtained showed significant influence of parity number on most of the reproductive parameters studied, apart from AWPB, PWM and AWPW. The total litter size at birth was the lowest in primiparous sows and in cases second-parity sows, but significantly exceeded the overall average population estimation during the fourth-sixth parities farrowing. The least squares estimates of the mortality rate of piglets at birth were significantly lower than in second parity sows, however they significantly increased in sows at eighth parity. The year of the sow's farrowing had the most significant influence on the weight of piglets at birth and at weaning. Moreover, a clear upward trend can be noted in relation to the weight of piglets at birth, which is accompanied by a gradual increase of the corresponding least squares estimates during 2007-2015. Late summer and early autumn (August-October) are the seasons when the litter size traits in the LW sows consistently show the lowest values, indicating a ‘seasonal infertility period’. Thus, all the analysis performed in the present work shows that in the LW sows, as in other pig breeds, the parity number, year and season farrowing influence the reproductive and developmental processes.

Porcine LIF gene polymorphisms and their association with litter size traits in four pig breeds

Leukemia inhibitory factor (LIF) is an important productivity-related gene in pigs. We found two polymorphisms — g.6646C&gt;T and g.6988C&gt;T — in exon 3 of LIF in pigs by using DNA sequencing and polymerase chain reaction-restriction fragment length polymorphism. Three genotypes were obtained and associated with litter size traits in Anqing Six-end-white (AQ), Wei (W), Wannan Black (WNB), and Large White (LW) pigs. At locus g.6646C&gt;T, the g.6646C allele frequency variation was 0.6869 (AQ), 0.7473 (W), 1 (WNB), and 0.6852 (LW). In AQ pigs, sows with the TT genotype had higher total number of piglets born (TNB) and number of piglets born alive (NBA) in the first parity and multiparities (P &lt; 0.01). In W and LW pigs, sows with the CC genotype had higher TNB and NBA in multiparities (P &lt; 0.01). At locus g.6988C&gt;T, the g.6988C allele frequency variation was 1 (AQ), 0.6154 (W), 1 (WNB), and 0.6667 (LW). The CC genotype significantly differed from CT or TT genotypes (P &lt; 0.01) for TNB and NBA in W and LW pigs. Thus, LIF was shown to have a significant influence on litter size. Therefore, g.6646C&gt;T and g.6988C&gt;T loci of LIF could be potential marker-assisted selection tools for improving litter size in pig production.

Method of individual forecasting of sow reproductive performance on the basis of a non-linear canonical model of a random sequence

Improvement of sow reproductive performance is a key factor determining the efficiency of the pig production cycle and profitability of pork production. This article presents the solution of an important scientific and practical problem of individual forecasting of sow reproduction . The population used for the present study is from a pig farm managed by the Limited Liability Company (LLC) ‘Tavriys’kisvyni’ located in Skadovsky district (Kherson region, Ukraine). The experimental materials used for this study consisted of 100 inds. of productive parent sows of the Large White breed.The litter size traits – the total number of piglets born (TNB), number of piglets born alive (NBA) and number of weaned piglets (NW) – were monitored in the first eight parities over an eleven year period (2007–2017). The method of the forecasting of sow litter size is developed based on the non-linear canonical model of the random sequence of a litter size change. The proposed method allows us to take maximum account of stochastic peculiarities of sow reproductive performance and does not impose any restrictions on the random sequence of a litter size change (linearity, stationarity, Markov property, monotony, etc.). The block diagram of the algorithm presented in this work reflects the peculiarities of calculation of the parameters of a predictive model. The expression for the calculation of an extrapolation error allows us to estimate the necessary volume of a priori and a posteriori information for achieving the required quality of solving the forecasting problem. The results of the numerical experiment confirmed the high accuracy of the proposed method of forecasting of sow reproduction. The method offered by us almost doubles the accuracy of forecasting of sow litter size compared to the use of the Wiener and Kalman methods. Thus, average forecast error decreases across the range of features TNB (1.71), NBA (1.68) and NW (1.25 piglets). Apparently, this may reflect a higher level of manifestation of the genetically determined level of individual sow fertility at the moment of piglet weaning. The higher adequacy of the developed mathematical model with regard to NW can be also due to the fact that the relations between sow litter size in different farrowings primarily have a non-linear character, which is taken into maximum account in our offered model. Given non-linearity, on the other hand, turns out to be a significant factor determining a lower estimation of the repeatability value for NW compared to the estimations for TNB and NBA. The use of the developed method will help to improve the efficiency of pig farming.

Variants in BMP7 and BMP15 3'-UTRs Associated with Reproductive Traits in a Large White Pig Population.

Bone morphogenetic protein 7 (BMP7) and BMP15, which encode members of the BMP family, have been identified by whole-genome resequencing as breeding-related genes that overlap with a known quantitative trait locus for reproductive traits. In this study, we investigated the effects of variants at the BMP7 and BMP15 gene loci on sow reproductive traits. We isolated 669 and 1213 bp sequences of the 3’-untranslated region (3’-UTR) of the porcine BMP7 and BMP15 genes, respectively, and detected several RNA regulatory elements, such as miRNA response elements and AU-rich elements. Pooled DNA sequencing identified two novel point mutations (viz., BMP7 c.1569A>G and BMP15 c.2366G>A) in the 3’-UTR. Association analysis showed that the c.1569A>G polymorphism was associated with the litter weight trait in a Large White pig population. Furthermore, analysis of the combined genetic effects revealed that AA/GA and AG/GG were the favorable combined genotypes for the total number of piglets born (TNB) and the total number of piglets born alive (NBA), whereas. Together, our findings confirm that BMP7 and BMP15 are candidate genes for porcine reproductive performance.

Additive Genetic Effects of RNF4, RBP4, and IGF2 Polymorphisms on Litter Size in Landrace and Yorkshire Sows

The association of the RNF4, RBP4, and IGF2 genotypes and their additive genetic effects with litter size in purebred Landrace and Yorkshire sows were studied. The results revealed significant associations between the RNF4 and RBP4 genotypes with the total number of piglets born (TNB) and number of piglets born alive (NBA) traits (P &lt;0.05). The RNF4 CC genotype had greater TNB and NBA than the TT genotype in both breeds. The RBP4 BB genotype had greater TNB and NBA than the AA genotype in the Landrace breed. Significant additive effects of the RNF4 and RBP4 genes on the TNB and NBA were detected (P &lt;0.05). No significant associations of the IGF2 genotypes and their additive effects with any reproductive traits were observed in both Landrace and Yorkshire sows (P &gt;0.05). The results suggested that the RNF4 and RBP4 genes could be useful in selection for increasing TNB and NBA traits in pigs.

Identification of resilient sows in Porcine Reproductive and Respiratory Syndrome virus infected farms.

The identification of resilient sows can improve reproductive performance in farms exposed to multiple challenges. A common challenge is the porcine reproductive and respiratory syndrome virus (PRRSV). A key issue to deal with disease resilience is to set up a feasible phenotyping strategy. Our aim was to develop a phenotyping criterion to discriminate susceptible from resilient sows in PRRSV-infected farms. A total of 517 Landrace x Large White gilts were classified as resilient (R) or susceptible (S) to PRRSV virus, following vaccination with MLV-PRRSV at 6-7 wk of age, in a PRRSV negative multiplication farm. Female piglets were phenotyped as R if their serum was negative to PRRSV at 7 and 21 d post-vaccination (DPV) or as S if their serum was positive at 7 and/or 21 DPV. Amongst them, 382 gilts were transferred to a PRRSV-positive production farm, where the number of piglets born alive (NBA), stillborn (NSB), mummified (NMU), lost (NLP=NSB+NMU) and total born (NTB = NBA+NLP) were recorded for almost three years. Data were collected during two periods according to the PRRSV farm health status, which were confirmed as either PRRSV-positive stable (endemic) or inestable (epidemic). Analyses were carried out under a Bayesian approach. The heritability for the resilience criterion was estimated using a threshold model. A linear (for NTB and NBA) and a binomial model (for NSB, NMU and NLP) on the resilience criterion by the farm health status were used to assess the difference between R and S sows. The heritability of the resilience criterion was 0.46 (SD 0.06). The probability of a piglet being lost was greater (≥0.97) in S than in R litters, regardless of whether the delivery occurred during a PRRSV outbreak (20.5% vs 17.0%) or not (15.8% vs 13.7%). The lower piglet mortality rate in R sows was due to NSB, in the endemic phase (13.0% vs 15.0% of NTB, with a posterior probability of 98% of S sows showing higher NSB than R sows), and to NMU, in the epidemic phase (4.0% vs 8.4% of NTB, with a posterior probability of >99% of S sows showing higher NMU than R sows). During a PRRSV outbreak, the S sows were twice as likely to give birth to a mummified piglet as compared to R sows. These findings provide evidence that the described phenotyping scheme has a potential use as a PRRSV resilience criterion.

Effect of genetic and non-genetic factors on the reproduction traits in Ukrainian Meat sows

Purebred Ukrainian Meat (UM) breed pigs, which came from Limited Liability Company “Tavriyskie Svin'I” herd located in Skadovsky district (Kherson region, Ukraine), were studied. The reproduction traits investigated were total number of piglets born (TNB), number of piglets born alive (NBA), frequency of stillborn piglets (FSB), number of weaned piglets (NW), total weaning weight of litter (TWWL) and average piglet weaning weight (APWW) for sows farrowing between 2006 and 2012. The analysis covered reproductive characteristics of 49 sows in the first nine parities (n = 457 litters). The sows originated from different the UM dam lines. Two month farrowing periods (January/February, March/April, May/June, July/August, September/October, and November/December) were constructed and used for reproduction traits. Data were analyzed by use of general linear model (GLM) procedure with the statistical package MINITAB v. 15. The estimates of reproduction traits for UM sows were 10.73 ± 0.43 ind. for TNB, 9.36 ± 0.39 ind. for NBA, 10.5 ± 2.2% for FSB, 9.07 ± 0.30 ind. for NW, 128.1 ± 5.7 kg for TWWL and 14.39 ± 0.49 kg for APWW. Litter size had a nonlinear effect on probability of stillbirth; piglets from small and large litters were more susceptible to die at farrowing with a minimum probability (near 5.0%) for intermediate litters of 8–10 piglets. Results here indicate that weak genetic variation exists in different the UM dam lines for the reproduction traits. Based on the obtained results it can be concluded that influence of parity on the observed traits of litter size was highly statistically significant (P &lt; 0.05–0.001). The TNB, NBA and NW decreased in the first-second parities and thereafter increased with the number of parities, reaching a maximum in parities 5 and 6. FSB was lowest in parities 2, 3 and 5. Farrowing month significantly influenced some reproduction traits also. Sows farrowing in May/June had the highest NW, TWWL and APWW.

Hypomethylation in the promoter region of ZPBP as a potential litter size indicator in Berkshire pigs.

In pigs, litter size is typically defined as the total number of piglets born (TNB) or the number of piglets born alive (NBA). Increasing pig litter size is of great economic interest as a means to increase productivity. The capacity of the uterus is a critical component of litter size and may play a central role in prolificacy. In this study, we investigated litter-size-related epigenetic markers in uterine tissue from Berkshire pigs with smaller litter size groups (SLGs) and larger litter size groups (LLGs) using genome-wide bisulfite sequencing (GWBS). A total of 3269 differentially methylated regions (DMRs) were identified: 1566 were hypermethylated and 1703 hypomethylated in LLG compared to SLG. The zona pellucida binding protein (ZPBP) gene was significantly hypomethylated in the LLG promoter region, and its expression was significantly upregulated in uterine tissue. Thus, the methylation status of ZPBP gene was identified as a potential indicator of litter size. Furthermore, we verified its negative correlation with litter size traits (TNB and NBA) in whole blood samples from 172 Berkshire sows as a blood-based biomarker by a porcine methylation-specific restriction enzyme polymerase chain reaction (PMP) assay. The results suggest that the methylation status of the ZPBP gene can serve as a valuable epigenetic biomarker for hyperprolific sows.

Association analysis of polymorphisms of G protein-coupled receptor 54 gene exons with reproductive traits in Jiaxing Black sows.

ObjectiveThe aim of this study was to detect single nucleotide polymorphisms (SNP) of G protein-coupled receptor 54 (GPR54) gene and explore association of this candidate gene with reproductive traits in Jiaxing Black sows.MethodsSix pairs of primers of the gene were designed to amplify all exons thus sequences of which were detected by means of direct sequencing and then SNP loci were scanned. The effects of SNPs on total number of piglets born (TNB), number of piglets born alive (NBA), number of still born piglets (NSB), and litter weight at birth (LWB) of Jiaxing Black sows were analyzed.ResultsThree SNP loci, including T3739C, C3878T and T6789C, were identified via comparison of sequencing and two genotypes (AB, BB) at each SNP site were observed. T3739C resulted in the change of amino acid (Leu→Pro) in corresponding protein, and C3878T resulted in synonymous mutation (Ile→Ile). Statistical results demonstrated that allele B was the preponderant allele at the three SNP loci and Genotype BB was the preponderant genotype. Meanwhile, Chi-Square test of these three SNPs indicated that all mutation sites fitted in Hardy-Weinberg equilibrium (p>0.05). For GPR54-T3739C locus, Jiaxing Black sows with genotype BB had 1.23 TNB and 1.28 NBA (p<0.01) that were more than those with genotype AB, respectively. Jiaxing Black sows that had the first two parities with genotype BB had additional 2.23 TNB, 2.27 NBA (p<0.01), and 1.94 LWB (p<0.05) compared to those with genotype AB, respectively. However, for other two loci, no significant difference was found between TNB, NBA, NSB, and LWB, and different genotypes of Jiaxing Black sows.ConclusionIn conclusion, the polymorphisms of GPR54-T3739C locus were significantly associated to TNB, NBA, and LWB and could be used as a potential genetic marker to improve reproductive function of Jiaxing black sows.

Polymorphism of mitochondrial tRNA genes associated with the number of pigs born alive

BackgroundMutations in mitochondrial tRNA genes have been widely reported association with human reproductions. It is also important to explore the effect on the number of piglets born alive (NBA). Here, 1017 sows were used to investigate the association between polymorphisms in mitochondrial tRNA genes and NBA.ResultsIn total, 16 mutations were found in mitochondrial tRNA genes, of which 13 mutations were significantly associated with NBA (P < 0.05). The reproductions of mutant carriers were significantly greater than that of wild carriers by 0.989 piglets born alive/sow farrowing. To test whether the mutations altered the structure of mitochondrial tRNAs, the secondary and tertiary structures were predicted. In result, C2255T changed the secondary structure of tRNA-Val by elongating the T stem and shrinking the T loop, and C2255T and G2259A in the tRNA-Val gene, C6217T and T6219C in the tRNA-Ala gene, and T15283C in the tRNA-Glu gene altered the tertiary structure of their tRNAs, respectively by changing the folding form of the T arm, and C16487T in the tRNA-Thr gene changed the tertiary structure of mitochondrial tRNA-Thr by influencing the folding form of the acceptor arm.ConclusionsResults highlight the effect of mitochondrial tRNA genes on the number of piglets born alive, and suggest that polymorphic sites of the tRNA genes be genetic markers for selection of pig reproduction.

Genetic Polymorphism of Microsatellite Loci and Their Association with Reproductive Traits in Ukrainian Meat Breed Pigs

The primary goal of the study was to estimate the genetic diversity and population structure of the Ukrainian Meat breed pigs. Twelve microsatellite markers were selected from the list of the microsatellites recommended by FAO/ ISAG. The range of alleles per locus (Na) was found to be from 5 to 14 with an average of 8.42, and a total of 101 alleles were observed at these loci. The observed heterozygosity (Ho) was averaged 0.668 and expected heterozygosity (He) was 0.718, respectively. The LD-based population effective size (Ne) estimate for the Ukrainian Meat breed pigs was 68.3 (95% CI: 52–92) individuals. This population has not undergone any recent and/or sudden reduction in the effective population size and remained at mutation–drift equilibrium. The SW24, SW951, SW240, S0101, SW936, and S0228 loci genotypes were found to affect the total number of piglets born (TNB), the number of piglets born alive (NBA), and the number of piglets weaned (NW).