Reproductive Performance Of Pigs Research Articles

ВЛИЯНИЕ ГЕНА TMEM132D НА ВОСПРОИЗВОДИТЕЛЬНЫЕ КАЧЕСТВА СВИНОМАТОК

An important task is to increase the efficiency of pig-breeding. Breeding to improve the reproductive qualities of sows will improve their reproductive performance and increase the volume of production. In this regard, the search for genetic variants associated with reproductive performance of pigs is of particular relevance and scientific importance. The aim of the study was to evaluate the effect of TMEM132D gene on reproductive performance of large white pigs and to consider it as a genetic marker for selection and breeding work.

CYP24A1 is associated with fetal mummification in pigs

Mummified piglets are among the leading causes of fertility loss and severely hamper reproductive performance in pigs. However, the contributions of genomic variation to the emergence of mummified piglets (MUM) have rarely been studied. This study aims to (1) elucidate the genetic architecture of MUM in sows of parity 1 - 3 using a single-step genome-wide association study (ssGWAS). The ssGWAS involved genotyping-by-sequencing of Large White and Landrace pig breeds. (2) Explore the biological role of the candidate genes at the cellular level. A total of 185 and 48 genome-wide significant SNPs are associated with MUM in Large White and Landrace pigs, explaining 0.01–36.52% genetic variance for different significant loci, respectively. All the significant SNPs are parity-specific, and the numerous, consecutive significant loci likely generated the nine significant peaks in different parities. Multiple candidate genes (including CYP24A1, FBXO30, and ARHGEF28) are associated with fetal congenital and maternal diseases. Collectively, CYP24A1 regulation contributes to steady-state levels of embryo development genes. CYP24A1 is involved in reproduction and, immune and gestational disorders. Thus, it is associated with known newborn death traits and MUM in Large White sows. Altogether, these results improve the current understanding of the genetic architecture of MUM and expand the knowledge on genetic variations for selecting against mummified piglets in pig breeding.

Atretic preovulatory follicles could be precursors of ovarian lutein cysts in the pig

Ovarian cysts contribute to reduced reproductive performance in pigs. Unfortunately, the mechanism of lutein cysts formation remains unknown. Here, we compared the endocrine and molecular milieus of intact, healthy preovulatory follicles (PF), gonadotropin (eCG/hCG)-induced healthy and atretic-like PF, as well as gonadotropin-provoked and spontaneous ovarian cysts in gilts. Several endocrine and molecular indicators and microRNA were compared in walls of PF and cysts. Intact and healthy PF, showed high estradiol/androstendione and low progesterone levels associated with CYP17A1, HSD17B1, and CYP19A1 elevation and reduced StAR/HSD3B1 protein expression. In contrast, low estradiol/androstendione and high progesterone concentrations, accompanied by decreased CYP17A1, HSD17B1, CYP19A1 and increased HSD3B1 protein abundance, appeared in atretic-like PF, gonadotropin-induced and spontaneous cysts. High progesterone receptor (PGR) protein abundance was maintained in intact and healthy PF, while it dropped in atretic-like PF, gonadotropins-induced and spontaneous cysts. The atretic PF showed high level of TNFα compared to healthy PF. In conclusion, follicular lutein cysts could be recruited from atretic-like PF with lost estrogenic milieu and inability to ovulate. Ovulatory cascade was presumably disrupted by a low PGR and high TNFα levels associated with earlier luteinization of follicular walls. These results suggest a novel mechanism of lutein ovarian cysts development in pigs and, perhaps, other species.

VITAMIN-HORMONAL STIMULATION INFLUENCE OF REPAIR PIGS ON THEIR REPRODUCTIVE INDICATORS AT DIFFERENT TIMES OF THE YEAR

The influence of vitamin-hormonal schemes of stimulation of replacement pigs on their reproductive function was studied. The effect of stimulation on the reproductive performance of pigs and fertility, multiple pregnancy in the spring and summer seasons was determined. A methodical approach has been created to increase the reproductive capacity of gilts. It was stated that multiple pregnancy (insemination in the spring season) was probably (P> 0.99) higher in the I-study group (use of the complex vitamin preparation Introvit) by 6.0% compared to the control. Comparing the results of farrowing in the II-study group (the use of the drug "Introvit" and the hormonal drug "Gestavet"), the multiple pregnancy rates were probably (P> 0.99) higher by 9.2% compared to the control group. In the III experimental group (use of the hormonal drug "Gestavet"), the indicators of multiple pregnancy exceeded the control group of animals by 8.3%. According to the results of farrowing (summer insemination) in the queens of the I-study group, where the complex vitamin preparation "Introvit" was used, the multiplicity was higher by 4.3% compared to the control. In the second experimental group, where the combination of the drug Introvit and the hormonal drug Gestavet was used, the multiple pregnancy rates were higher by 7.7% compared to the control. In the III experimental group, when using the hormonal preparation "Gestavet", the indicators of multiple pregnancy exceeded the control group of animals by 7.5% compared to the control. When using vitamin-hormonal stimulation, there is an increase in fertility by 9.2% (insemination in the spring) and 7.7% (in the summer). It was found that the best in terms of reproductive ability was the vitamin-hormonal scheme for the treatment of pigs (experimental group II), both in the spring and summer seasons. Keywords: gilts, hormonal, vitamin preparations, multiple pregnancy, seasons.

Heterozygosity and homozygosity regions affect reproductive success and the loss of reproduction: A case study with litter traits in pigs

Runs of heterozygosity (ROHet) and homozygosity (ROH) harbor useful information related to traits of interest. There is a lack of investigating the effect of ROHet and ROH on reproductive success and the loss of reproduction in mammals. Here, we detected and characterized the ROHet and ROH patterns in the genomes of Chinese indigenous pigs (i.e., Jinhua, Chun’an, Longyou Black, and Shengxian Spotted pigs), revealing the similar genetic characteristics of indigenous pigs. Later, we highlighted the underlying litter traits-related ROHet and ROH using association analysis with linear model in these four indigenous pig breeds. To pinpoint the promising candidate genes associated with litter traits, we further in-depth explore the selection patterns of other five pig breeds (i.e., Erhualian, Meishan, Minzhu, Rongchang, and Diqing pigs) with different levels of reproduction performance at the underlying litter traits-related ROHet and ROH using FST and genetic diversity ratio. Then, we identified a set of known and novel candidate genes associated with reproductive performance in pigs. For the novel candidate genes (i.e., CCDC91, SASH1, SAMD5, MACF1, MFSD2A, EPC2, and MBD5), we obtained public available datasets and performed multi-omics analyses integrating transcriptome-wide association studies and comparative single-cell RNA-seq analyses to uncover the roles of them in mammalian reproductive performance. The genes have not been widely reported to be fertility-related genes and can be complementally considered as prior biological information to modify genomic selections models that benefits pig genetic improvement of litter traits. Besides, our findings provide new insights into the function of ROHet and ROH in mammals.

The effect of the SCD genotype on litter size and weight at weaning

Genetic markers associated with meat quality may have adverse effects on reproduction performance, as shown for a variant in the leptin receptor (LEPR) gene. There is a single nucleotide polymorphism (SNP) in the stearoyl-CoA desaturase (SCD) gene that influences the monounsaturated fatty acid content of pork. Here, we investigate single and combined effects of the SCD (rs80912566 T>C) and LEPR (rs709596309 C>T) SNP on litter size and weaning weight. A total of 1,246 sows of known genotype for SCD (732 of which were also genotyped for LEPR) were monitored for age at farrowing, number of piglets born, born alive and weaned, and litter weight at weaning during two years. The effects of these SNP and of a variant in the diacylglycerol O-acyltransferase 2 (DGAT2) gene on milk fat content and fatty acid composition were also analysed in 99 primiparous sows. No adverse effects of the SCD SNP on overall reproductive performance were observed. However, in primiparous sows, we found that the SCD-T allele, the one that increases the monounsaturated fatty acid content, influenced negatively the weight of piglets at weaning (the piglets from SCD-TT sows weighted 126 g less at weaning than those from SCD-CT sows), especially in combination with the LEPR-TT genotype (the piglets from SCD-TT/LEPR-TT sows weighted 277 g less at weaning than piglets from SCD-C−/LEPR-C− sows). In contrast to SCD, the negative effect of the LEPR-TT sows on the piglets weaning weight was maintained in all parities (piglets from LEPR-TT sows were on average 126 g lighter than LEPR-C− sows). The unfavourable effect of the SCD-T allele on the litter weight of primiparous sows could be due to lower body reserves at first farrowing (SCD-TT pigs had 0.62 mm less backfat thickness at 205 d than SCD-CT pigs) together with larger litters at birth (the SCD-TT sows had 0.32 more piglets born alive per litter than the SCD-CT sows). The milk of primiparous sows with the SCD-T allele showed higher desaturation indices (i.e. higher monounsaturated to saturated fatty acid ratios), but lower fat content. No relevant effects of the DGAT2 SNP on milk traits were found. In conclusion, the SCD SNP does not impact overall reproductive performance in pigs, but cautious management of SCD-TT gilts is recommended.

Concordance rate in cattle and sheep between genotypes differing in Illumina GenCall quality score.

Proper quality control of data prior to downstream analyses is fundamental to ensure integrity of results; quality control of genomic data is no exception. While many metrics of quality control of genomic data exist, the objective of the present study was to quantify the genotype and allele concordance rate between called single nucleotide polymorphism (SNP) genotypes differing in GenCall (GC) score; the GC score is a confidence measure assigned to each Illumina genotype call. This objective was achieved using Illumina beadchip genotype data from 771 cattle (12428767 genotypes in total post-editing) and 80 sheep (1557360 SNPs genotypes in total post-editing) each genotyped in duplicate. The called genotype with the lowest associated GC score was compared to the genotype called for the same SNP in the same duplicated animal sample but with a GC score of >0.90 (assumed to represent the true genotype). The mean genotype concordance rate for a GC score of <0.300, 0.300-0.549, and ≥0.550 in the cattle (sheep in parenthesis) was 0.9467 (0.9864), 0.9707 (0.9953), and 0.9994 (0.99997) respectively; the respective allele concordance rate was 0.9730 (0.9930), 0.9849 (0.9976), and 0.9997 (0.99998). Hence, concordance eroded as the GC score of the called genotype reduced, albeit the impact was not dramatic and was not very noticeable until a GC score of <0.55. Moreover, the impact was greater and more consistent in the cattle population than in the sheep population. Furthermore, an impact of GC score on genotype concordance rate existed even for the same SNP GenTrain value; the GenTrain value is a statistical score that depicts the shape of the genotype clusters and the relative distance between the called genotype clusters.

Transcriptome analysis identifies genes and co-expression networks underlying heat tolerance in pigs

BackgroundHeat stress adversely affects pig growth and reproduction performance by reducing feed intake, weight gain, farrowing rate, and litter size. Heat tolerance is an important characteristic in pigs, allowing them to mitigate the negative effects of heat stress on their physiological activities. Yet, genetic variation and signaling pathways associated with the biological processes of heat-tolerant pigs are currently not fully understood. This study examined differentially expressed genes and constructed gene co-expression networks on mRNAs of pigs under different heat-stress conditions using whole transcriptomic RNA-seq analyses. Semen parameters, including total sperm number per ejaculate, motility, normal morphology rate, droplets, and rejected ejaculate rate, were measured weekly on 12 boars for two time periods: thermoneutral (January to May), and heat stress (July to October). Boars were classified into heat-tolerant (n = 6) and heat-susceptible (n = 6) groups based on the variation of their ejaculate parameters across the two periods. RNA was isolated from the blood samples collected from the thermoneutral and heat stress periods for gene expression analysis.ResultsUnder heat stress, a total of 66 differentially expressed genes (25 down-regulated, 41 up-regulated) were identified in heat-tolerant pigs compared to themselves during the thermoneutral period. A total of 1041 differentially expressed genes (282 down-regulated, 759 up-regulated) were identified in the comparison between heat-tolerant pigs and heat-susceptible pigs under heat stress. Weighted gene co-expression network analysis detected 4 and 7 modules with genes highly associated (r > 0.50, p < 0.05) with semen quality parameters in heat-tolerant and heat-susceptible pigs under the effects of heat stress, respectively.ConclusionThis study utilized the sensitivity of semen to heat stress to discriminate the heat-tolerance ability of pigs. The gene expression profiles under the thermoneutral and heat stress conditions were documented in heat-tolerant and heat-susceptible boars. Findings contribute to the understanding of genes and biological mechanisms related to heat stress response in pigs and provide potential biomarkers for future investigations on the reproductive performance of pigs.

Effects of fixed-time artificial insemination using triptorelin on the reproductive performance of pigs: a meta-analysis

Triptorelin (TRI), a gonadotropin-releasing hormone agonist allowing ovulation synchronization in pigs, is indispensable for fixed-time artificial insemination (FTAI) protocols. However, the effect of FTAI using TRI (FTAI-TRI) on the reproductive performance is controversial. We performed a meta-analysis to determine whether FTAI-TRI affects reproductive performance of pigs, including pregnancy rate (PR), number of pigs born alive per litter (NBA), farrowing rate (FR) and total number of pigs born per litter (TNB). A total of 37 trials from 15 studies were extracted and analysed in Stata. A weighted mean difference (WMD) with 95% confidence interval (CI) was calculated for NBA and TNB, and risk ratio (RR) with 95% CI was calculated for PR and FR. Pregnancy rate, TNB and NBA data were applied to a fixed-effect protocol, and FR data were applied to a random-effect protocol. We found that for weaned sows, the FTAI-TRI group had comparable reproductive performance to the artificial insemination (AI) following oestrus detection (EDAI) group. Fixed-time AI has many advantages, including the elimination of the need to heat-check twice daily, so that FTAI-TRI is a good substitute for EDAI. Subgroup analysis indicated that the optimal timing of triptorelin treatment was 96 h after weaning, which gave significant positive effects on PR (RR = 1.08, P = 0.000) and non-significant positive effects on TNB (WMD = 0.12, P = 0.452). Triptorelin at a dose of 100 μg showed better effects than 200 μg, with significant positive effects on PR (RR = 1.09, P = 0.005) and FR (RR = 1.06, P = 0.036). So a single dose of 100 μg was recommended. The optimal protocol was insemination at 24 h and again at 48 h after triptorelin administration if they remained in standing oestrus, and this provided a significantly higher NBA (WMD = 0.59, P = 0.013) that increased by 0.59. For gilts, the FTAI-TRI group showed decreased (not significant) PR (RR = 0.96, P = 0.127) and significantly decreased FR (RR = 0.93, P = 0.013), TNB (WMD = −0.85, P = 0.006) and NBA (WMD = −0.98, P = 0.000), which were inferior to those in the EDAI group. In conclusion, the effects of FTAI-TRI on the reproductive performance of pigs were parity-, treatment timing-, insemination timing-, and dosage-dependent. Fixed-time AI using triptorelin could effectively replace the EDAI protocol for sows, but not for gilts.

153 The effects of parity and oxytocin or prostaglandin F2α added to insemination doses on reproductive performance of pigs bred in summer

Summer is the least favourable season for swine reproduction, mainly due to long photoperiods and heat stress. Such conditions negatively impinge on the reproductive system of sows and boars, manifesting in debilitated uterine and gonadal function. This situation is exacerbated by the dilution of ejaculates in semen extender before AI. Consequently, there is a noticeable decline in piglet productivity of summer-breeding gilts and sows. The main goal of this study was to determine the effect of oxytocin (OX) or prostaglandin F2α analogue (PG) added to boar semen extender on the duration of insemination and reproductive performance of pigs bred in July and August. A total of 144 females (80 gilts and second-parity sows (G+SP) and 64 multiparous sows (M)) were divided into three groups (n=48 per group). The OX (11 G+SP and 37M) and PG (20 G+SP and 28M) groups were inseminated twice (at the onset of behavioural oestrus and 22-24h later) using semen supplemented with 20IU of OX or 5mg of PG, respectively; the controls (33 G+SP and 15M) were artificially inseminated with non-supplemented inseminate doses. Pregnancy was detected ultrasonographically on gestational day 42, and the number and viability of piglets were recorded at farrowing. Proportions were analysed using chi-square test (Brandt and Snedecor formula), and other numerical data were analysed using two-way analysis of variance and least significant difference test to determine the differences between individual mean values (SigmaPlot, Systat Software Inc.). The mean duration of first insemination was shorter (P&amp;lt;0.05) in M females (80±22s) compared with G+SP females (191±26s) inseminated with PG-supplemented semen, whereas the second insemination was shorter (P&amp;lt;0.05) in M females than in G+SP females artificially inseminated with OX-supplemented semen (93±15s compared with 192±28s). The mean pregnancy rate was lower (P&amp;lt;0.05) in control G+SP females (26/33; 85%) than in OX G+SP females (11/11; 100%). The farrowing rate was less (P&amp;lt;0.05) in control females (36/48; 75%) than in OX females (44/48; 92%), and it was less (P&amp;lt;0.05) in PG G+SP females (14/20; 70%) compared with PG M females (26/28; 93%). The M females in the OX group had more (P&amp;lt;0.05) stillborn piglets per litter compared with their G+SP counterparts (0.6±0.1 vs. 0.1±0.1). Overall, PG females had more (P&amp;lt;0.05) weak piglets per litter (1.2±0.2) compared with the control (0.5±0.2) and OX (0.6±0.2) groups. The present results reveal the occurrence of both beneficial and undesirable effects of PG and OX added to boar semen extender on reproductive performance of breeding pigs in summer. Addition of PG was associated with shorter first-insemination times in older sows compared with G+SP animals but also with lower farrowing rates in younger animals and an overall increase in the number of weak piglets at farrowing. Supplementation of OX was in turn associated with a shorter second insemination and higher pregnancy rates in young females but more stillborn piglets per litter in multiparous sows. The specific causative mechanisms of these associations remain to be elucidated.

Effects of N-carbamylglutamate and arginine on steroidogenesis and proliferation of pig granulosa cells in vitro

Results of in vivo studies indicate dietary N-carbamylglutamate (NCG) and arginine (ARG) can enhance reproductive performance in gilts. It was hypothesized that both NCG and ARG will alter hormone-induced estradiol (E2) production by granulosa cells (GC), explaining why these compounds could improve reproductive performance in pigs. The objective of these studies, therefore, was to evaluate the direct effects of NCG and ARG on porcine GC proliferation and steroidogenesis, using an in vitro cell culture system. The GC from small (SM; 1–5 mm) and large (LG; >5 mm) pig follicles were cultured for 2 days in 5% fetal bovine serum and 5% porcine serum-containing medium followed by 2 days in serum-free medium containing 500 ng/mL of testosterone (as an E2 precursor), and NCG or ARG at various doses in the presence of either follicle-stimulating hormone (FSH; 30 ng/mL), insulin-like growth factor-1 (IGF1; 30 ng/mL), or both. Numbers of GC were determined at the end of the experiment and concentrations of progesterone (P4) and E2 in culture medium were determined. Results indicated that LG-follicle GC were more responsive to NCG and ARG than SM-follicle GC. Specifically, in LG-follicle GC, NCG inhibited (P < 0.05) basal and FSH-induced P4 and E2 production but stimulated cell numbers; whereas ARG inhibited FSH-induced E2 production and cell numbers. In SM-follicle GC, treatment with NCG and ARG decreased IGF1 plus FSH induced P4 production, but E2 production and cell proliferation were not affected. These studies indicate that NCG and ARG may directly affect follicular function in pigs.

Production of homeobox A10 gene transgenic pigs by somatic cell nuclear transfer

Homeobox A10 (Hoxa10) gene is one of the most important candidate genes associated with the reproductive performance of humans and mice. Overexpression of Hoxa10 in mouse endometrium can increase litter size. Moreover, Hoxa10 plays a key role in regulating the embryo implantation of sows. This study aimed to generate transgenic pigs using Hoxa10 via somatic cell nuclear transfer (SCNT). We established seven Hoxa10-transgenic cell lines, and two of the cell lines were selected as nuclear donors for the transfer. A total of 1270 cloned embryos were generated and transferred to five surrogate mothers (Landrace×Yorkshire). Eight cloned male piglets were produced including one with cryptorchidism. Six transgenic piglets grew up healthy and produced 56 offspring. Finally, we obtained six transgenic male pigs and 26 transgenic positive offspring that can be used to further study the regulatory mechanism of Hoxa10 on the reproductive performance of pigs.

Reproductive performance of pigs raised by intensive management system in Abuja, Nigeria.

Background:Population growth led to an increase in the number of people raising pigs, resulting in increased demand for piglets/pigs for breeding and pork for consumption.Aim:This study was carried out to determine the reproductive performance of pigs raised by the intensive management system in Abuja, Nigeria, with a view to assist farmers in ensuring improved productivity and profitability.Materials and Methods:Using an interview-based questionnaire, data from 121 sows and 649 preweaning piglets were collected in 12 herds, from September 2017 to March 2018. Measures of reproductive and production performance assessed in this study were interfarrowing interval (IFI), number of liveborn piglets (NLB), preweaning piglet mortality (PPM), age at weaning (AAW), weaning to service interval (WSI), age at first farrowing (AFF), number of piglets weaned per litter (NPWL), and number of piglets weaned per sow per year (NPWPY).Results:The results obtained in this study were IFI 6.2±0.84 months, NLB 7.2±1.11, PPM 31%, AAW 40.2±3.12 days, NPWL 5.3±0.73, WSI 39.4±4.59 days, AFF 9.1±0.60 months, and NPWPY 8.1±1.21. The identified causes of PPM were maternal overlay 31.34%, splay leg/hypoglycemia 22.39%, cannibalism 20.40%, starvation 14.93%, and unknown cause 10.94%.Conclusion:The result showed that the reproductive performance of the sow (especially, NPWPY and PPM) needs to be improved on. There is a need to promote extension and herd health services by veterinarians and livestock personnel to potential and existing farmers in the area. This is more so because organized pig production in the studied area is relatively new and more people are establishing pig farms in the studied area.

Influence of different altitudes on productive and reproductive performance of pigs

Upgraded (Hampshire × Indigenous, 270) pigs were distributed to 9 families each in 10 villages situated at different altitudes in Nagaland with 1 male and 2 female pigs/family. Significant higher body weight was recorded at high altitudes, i.e. Porba, Chare and Kohima villages as compared to foothills villages like Murise. Average litter size and weight at birth and weaning were 7.65, 5.17, 5.99 and 10.13 kg, respectively, with furrowing of 60%. Minimum and maximum age at sexual maturity and age at first conception ranged between 7.51 to 7.89 and 8.65 to 9.00 months, respectively. The age at first furrowing and gestation period ranged from 12.48 to 12.77 months and 114 to 117 days, respectively. It can be concluded that body weight gain, litter size and weight at birth and weaning, age at sexual maturity, first conception and gestation period were within the normal range at various altitudes but higher than the indigenous pigs.

TRIENNIAL REPRODUCTION SYMPOSIUM: Developmental programming of fertility.

The 2015 Triennial Reproduction Symposium focused on developmental programming of fertility. The topics covered during the morning session included the role of the placenta in programming of fetal growth and development, effects of feeding system and level of feeding during pregnancy on the annual production cycle and lifetime productivity of heifer offspring, effects of litter size and level of socialization postnatally on reproductive performance of pigs, effects of postnatal dietary intake on maturation of the hypothalamic-pituitary-gonadal axis and onset of puberty in heifers, effects of housing systems on growth performance and reproductive efficiency of gilts, and effects of energy balance on sexual differentiation in rodent models. The morning session concluded with presentation of the American Society of Animal Science L. E. Casida Award for Excellence in Graduate Education to Dr. Michael Smith from the University of Missouri, Columbia, who shared his philosophy of graduate education. The afternoon session included talks on the role of epigenetic modifications in developmental programming and transgenerational inheritance of reproductive dysfunction, effects of endocrine disrupting compounds on fetal development and long-term physiology of the individual, and potential consequences of real-life exposure to environmental contaminants on reproductive health. The symposium concluded with a summary talk and the posing of 2 questions to the audience. From an evolutionary standpoint, programming and epigenetic events must be adaptive; when do they become maladaptive? If there are so many environmental factors that induce developmental programming, are we doomed, and if not, what is or are the solution or solutions?

Reproductive performance in pigs reared under organic conditions compared with conventionally reared pigs

BackgroundTo achieve a competitive reproductive performance in organic pig farming is a major challenge for this farming practise. Practices and research data regarding conventional pig production are not always applicable to organic production, why field studies are needed to identify differences in performance between organic and conventional pig farms in order to identify areas for improvement.ResultsPerformance data for one year was collected from 5 organic herds that had more than 30 sows in production and used a computerized recording system, and data from five nearby conventional farms with more than 30 sows and the same recording system were used as a comparison. In total data from 4697 farrowings were analyzed. In the organic pig herds, there were a higher total number of piglets born per litter (p=0.001), a higher number of piglets stillborn per litter (p<0.001), but a tendency (p<0.06) to lower number of weaned pigs per litter and longer nursing period (p<0.001) and farrowing interval (p<0.001).ConclusionsThe reproductive performance was lower in the organic herds and the variation in reproductive performance among the organic herds was larger than among the conventional ones, suggesting options for improvement in the organic herds.

PGF&lt;SUB&gt;2&amp;alpha;&lt;/SUB&gt;投与量が豚の発情周期および繁殖成績におよぼす効果

PGF&lt;SUB&gt;2&amp;alpha;&lt;/SUB&gt;投与量が豚の発情周期および繁殖成績におよぼす効果

Semen controlled-release capsules allow a single artificial insemination in sows

Controlled-release capsules containing boar spermatozoa were developed to extend the preservation time of spermatozoa and maximize the efficiency of a single artificial insemination. A large trial (4245 sows) was performed with these capsules using double/triple conventional artificial insemination as a control. The effect of treatment on pregnancy diagnosis, delivery, and born piglets was investigated, with allowance being made for considering season, spermatozoa amount, and the weaning-to-estrus interval as confounding variables. The same pregnancy rate and prolificacy were obtained by two insemination techniques, and a higher parturition frequency was reached with capsules. The reproductive performance in pigs has therefore been optimized by a single instrumental insemination with controlled-release capsules.

Effects of a trichothecene, T-2 toxin, on proliferation and steroid production by porcine granulosa cells

Fusarium mycotoxins, such as trichothecenes and zearalenone, are produced by molds and contaminate a large variety of grains and feedstuffs worldwide. Mycotoxins of Fusarium fungi include the trichothecenes, deoxynivalenol and T-2 toxin (T2), and zearalenone, and have been implicated in poor reproductive performance in pigs. However, direct ovarian effects of T2 toxin have not been reported. Therefore, porcine granulosa cells (GC) from small follicles (1–5 mm) were cultured for 2 days in 5% fetal bovine serum and 5% porcine serum-containing medium followed by 2 days in serum-free medium containing various doses of FSH, insulin-like growth factor-I and T2 (at various doses/combinations) to evaluate the influence of T2 on steroid production and cell proliferation. T2 at 1, 3, 30 and 300 ng/mL completely inhibited FSH plus IGF-I-induced estradiol production, whereas 0.3 ng/mL of T2 inhibited estradiol production by 40%. Progesterone production was less sensitive to the inhibitory effects of T2 with 0.3 ng/mL having no effect and 1 ng/mL inhibiting progesterone production by only 30%. At 30 and 300 ng/mL, T2 completely inhibited FSH plus IGF-I-induced progesterone production. The impact of T2 on the dose–response to IGF-I (0, 3, 10 and 30 ng/mL) was also evaluated; T2 blunted the stimulatory effect of 3–30 ng/mL of IGF-I on steroid production and cell proliferation. Serum-induced granulosa cell proliferation was decreased ( P < 0.05) by 40% after 1 day and by 56% after 2 days of T2 treatment. The present studies indicate for the first time that T2 may be able to alter in growth of the granulosa layer within ovarian follicles in addition to their effect on steroidogenesis. In conclusion, T2 has potent direct dose-dependent effects on granulosa cell proliferation and steroidogenesis. These direct ovarian effects could be one mechanism whereby contaminating Fusarium mycotoxins in feedstuffs could impact reproductive performance in swine.

Genetic parameters for litter size and weight at different parities in Iberian pigs

Genetic progress for reproductive performance in pigs is limited by mothering ability. It is a critical aspect for dam lines, in which litter weight at weaning could be included with litter size in the selection goal. Our objective was to investigate in Iberian pigs the genetic basis of the number of alive born piglets (NBA) and the litter weight at 21days (LW21) over the successive parities (t). Records for NBA were available from 6,775 litters born from 1,893 sows of the Torbiscal line, and LW21 records proceeded from 1,431 sows and 2,963 litters without crossfostering. Genetic parameters were estimated using an animal model with repeatability, a multi-trait animal model, and a random regression model. Estimated values of heritabilities for NBA and genetic correlations between parities confirm a partially different genetic control of prolificacy at parity 1 and at later parities. Results for LW21 indicate that this trait may be partially controlled by different genes at the first two parities and at the later ones. Estimated genetic parameters for NBA (t = 1), NBA (t &gt;/= 2), LW21 (t /= 3) were: heritability, hE2 = 0.15, 0.12, 0.22 and 0.15, respectively, and coefficient of permanent environmental effects, pE2 = 0.05, 0.02 and 0.24, respectively for the three last traits. The values of genetic correlations ranged from 0.44 to 0.84. A multitrait approach would be useful to estimate accurate genetic parameters, and to improve the low persistency of reproductive performance in the later parities of Iberian sows.