Characterizing sow feed intake during lactation to explain litter and subsequent farrowing performance.

Variation in feed intake results in nearly 20% of sows consuming less than the recommended lysine (Lys) intake for lactating sows. The Lys requirement for lactating sows is based on litter size and piglet average daily gain which influences milk production. Litter size continues to increase every year causing the need for routine reevaluation of nutrient requirements. If dietary inclusion levels are not continuously adjusted this can lead to inadequate daily Lys and energy intake and may negatively impact sow body condition and litter performance. The objective was to characterize the average daily feed intake (ADFI) of sows and define feed intake patterns and their effects on sow body weight, farrowing performance, litter performance, and subsequent farrowing performance. ADFI during lactation was recorded for 4,248 sows from 7 independent research studies. Data collection occurred from November 2021 through November 2023 at a commercial breed-to-wean facility in western Illinois. Each sow was categorized as: consistently low intake (< 5.5 kg/d) throughout the lactation (LLL); low intakes (< 5 kg/d) in the first week, then gradually increased throughout the rest of the lactation period (LHH); gradual increase in intake throughout lactation with no drop and a peak intake after day 10 of lactation (gradual); rapid increase in intake with no drop and the peak intake met before day 10 (rapid); a major drop in feed intake (> 1.6 kg decrease for ≥ 2 d) any time during lactation (MAJOR); minor drop (≤ 1.6 kg for ≥ 2 d; MINOR). Sows were also separated into low (quartile 1; ≤ 25%), average (quartile 2 through 3), or high feed intake (quartile 4; ≥ 75%) by parity (P1, P2, P3+). Sows in the LLL category were younger in parity, had the greatest preweaned mortality, weaned the lightest average pigs, and experienced the greatest loss in body weight percentage compared with sows in all other feed intake categories. Furthermore, sows in the LLL and LHH categories had one fewer subsequent pig born compared with sows in the other four categories. These data support historical findings that feed intake patterns directly contribute to current litter farrowing performance. Lactation intake patterns also influence subsequent farrowing performance. Identifying under-consuming sows that are likely Lys and energy deficient allows producers opportunities to promote consistent, adequate daily intakes to these groups and mitigate negative impacts on sow and litter performance.

This study investigated different sow feed intake patterns during lactation and average daily feed intakes within parity on current and subsequent farrowing and litter performance. Findings revealed sows that have consistently low intake throughout the lactation period have a significant reduction in average pig wean weight, a greater percentage of pre-wean mortality, and take an additional day or longer to return to estrus compared with sows that have average or above feed intake throughout the lactation period. Specifically, older parity sows were heavier, had greater feed intake, nursed heavier litters, and had litters with less preweaned mortality compared with younger parity sows. The average pig weaned weight and subsequent total pigs born improved as intake increased within parity. Prewean mortality decreased as feed intake increased within parity. These findings highlight the importance of ensuring sows are not only eating enough, but that they are consuming more than average when possible, to continually improve current and subsequent farrowing and litter performance. This study provides important information that will allow producers to target specific under-consuming sows and then promote consistent and high daily lactation intakes. Targeting these potentially nutrient-restricted sows may help reduce negative impacts on sow and litter performance.

Microbiome composition as a potential predictor of longevity in rabbits.

BACKGROUND: Longevity and resilience are two fundamental traits for more sustainable livestock production. These traits are closely related, as resilient animals tend to have longer lifespans. An interesting criterion for increasing longevity in rabbit could be based on the information provided by its gut microbiome. The gut microbiome is essential for regulating health and plays crucial roles in the development of the immune system. The aim of this research was to investigate if animals with different longevities have different microbial profiles. We sequenced the 16S rRNA gene from soft faeces from 95 does. First, we compared two maternal rabbit lines with different longevities; a standard longevity maternal line (A) and a maternal line (LP) that was founded based on longevity criteria: females with a minimum of 25 parities with an average prolificacy per parity of 9 or more. Second, we compared the gut microbiota of two groups of animals from line LP with different longevities: females that died/were culled with two parities or less (LLP) and females with more than 15 parities (HLP). RESULTS: Differences in alpha and beta diversity were observed between lines A and LP, and a partial least square discriminant analysis (PLS-DA) showed a high prediction accuracy (> 91%) of classification of animals to line A versus LP (146 amplicon sequence variants (ASV)). The PLS-DA also showed a high prediction accuracy (> 94%) to classify animals to the LLP and HLP groups (53 ASV). Interestingly, some of the most important taxa identified in the PLS-DA were common to both comparisons (Akkermansia, Christensenellaceae R-7, Uncultured Eubacteriaceae, among others) and have been reported to be related to resilience and longevity. CONCLUSIONS: Our results indicate that the first parity gut microbiome profile differs between the two rabbit maternal lines (A and LP) and, to a lesser extent, between animals of line LP with different longevities (LLP and HLP). Several genera were able to discriminate animals from the two lines and animals with different longevities, which shows that the gut microbiome could be used as a predictive factor for longevity, or as a selection criterion for these traits.

Genetic variant of the sheep E2F8 gene and its associations with litter size.

The economic efficiency of sheep breeding, aiming to enhance productivity, is a focal point for improvement of sheep breeding. Recent studies highlight the involvement of the Early Region 2 Binding Factor transcription factor 8 (E2F8) gene in female reproduction. Our group's recent genome-wide association study (GWAS) emphasizes the potential impact of the E2F8 gene on prolificacy traits in Australian White sheep (AUW). Herein, the purpose of this study was to assess the correlation of the E2F8 gene with litter size in AUW sheep breed. This work encompassed 659 AUW sheep, subject to genotyping through PCR-based genotyping technology. Furthermore, the results of PCR-based genotyping showed significant associations between the P1-del-32bp bp InDel and the fourth and fifth parities litter size in AUW sheep; the litter size of those with genotype ID were superior compared to those with DD and II genotypes. Thus, these results indicate that the P1-del-32bp InDel within the E2F8 gene can be useful in marker-assisted selection (MAS) in sheep.

FecB Was Associated with Litter Size and Follows Mendel's Laws of Inheritance When It Transited to Next Generation in Suhu Meat Sheep Breeding Population.

In order to investigate the effect of FecB on litter size and growth and development traits of Suhu meat sheep and the inheritance patterns of FecB between parents and offspring in the population. In this experiment, 2241 sheep from the Suhu meat sheep population were tested for FecB using capillary electrophoresis. We combined the lambing records of 473 ewes, the growth trait records of 881 sheep at both the birth and weaning (2-month-old) stages, and the complete genealogical records of 643 lambs to analysis the distribution of FecB in the Suhu meat sheep breeding population, its effect on litter size of ewes, growth and development of lambs, and the inheritance patterns of FecB. The results showed that there were three genotypes of FecB in the Suhu meat sheep population, namely the AA genotype, AG genotype, and GG genotype. FecB in this population has a moderate polymorphism (0.25 < PIC < 0.5), and deviates from Hardy-Weinberg disequilibrium (p < 0.05). The litter size of GG genotype ewes was significantly higher than that with the AG and AA genotypes (p < 0.01). A Chi-square test showed that the inheritance patterns of FecB follows Mendel's Laws of Inheritance (p > 0.05). An association analysis of different genotypes of FecB with body weight and body size of Suhu meat sheep at birth and weaning revealed that FecB adversely affects the early growth and development of Suhu meat sheep. In summary, FecB can improve the litter size of ewes but it has negative effects on the early growth and survival rate of lambs in sheep. Therefore, FecB test results and feeding management measures should be comprehensively applied to improve the reproductive performance of ewes, the survival rate and production performance of lambs in sheep production, and thus improve the economic benefits of sheep farms.

An Identification of Functional Genetic Variants in B4GALNT2 Gene and Their Association with Growth Traits in Goats.

ß-1,4-N-acetylgalactosamine transferase 2 (B4GALNT2) is a vital candidate gene that affects the growth traits in sheep. However, whether it has the same function in goats remains to be investigated further. This study selected 348 Nanjiang Yellow goats, screened all exons, and conserved non-coding regions of the B4GALNT2 gene for single-nucleotide polymorphisms (SNPs). Our results revealed the presence of a synonymous mutation, rs672215506, within the exon of the B4GALNT2 gene in the Nanjiang Yellow goat population. The mutation resulted in a decrease in the mRNA stability of the B4GALNT2 gene. The results of SNP detection of the conserved non-coding region of the B4GALNT2 gene showed five potential regulatory SNPs in the Nanjiang Yellow goat population. Except for rs66095343, the ~500 bp fragments of the other four SNPs (rs649127714, rs649573228, rs652899012, and rs639183528) significantly increased the luciferase activity both in goat skeletal muscle satellite cells (MuSCs) and 293T cells. The genetic diversity indexes indicated low or intermediate levels for all six SNPs analyzed, and the genotype frequencies were in Hardy-Weinberg equilibrium. Association analysis showed that rs660965343, rs649127714, and rs649573228 significantly correlate with growth traits in the later stage of growth and development of Nanjiang Yellow goats. The haplotype combinations of H2H3 and H2H2 had higher body weight and greater body size. Moreover, H2H2 haplotype combinations significantly correlated with the litter size of the Nanjiang Yellow goats. The results of our study demonstrate the potential role of the B4GALNT2 gene as a functional genetic marker in the breeding programs of Nanjiang Yellow goats.

Genome-Wide DNA Methylation Analysis and Functional Validation of Litter Size Traits in Jining Grey Goats.

DNA methylation (DNAm) is associated with the reproductive system. However, the genetic mechanism through which DNAm regulates gene expression and thus affects litter size in goats is unclear. Therefore, in the present work, genome-wide DNAm profiles of HP and LP Jining Grey goat ovary tissues were comprehensively analyzed via WGBS, and RNA-Seq data were combined to identify candidate genes associated with litter size traits in the Jining Grey goat. Finally, BSP and RT-qPCR were used to verify the sequencing results of the key genes. Notably, the DNMT genes were downregulated at the expression level in the HP group. Both groups exhibited comparable levels of methylation. A total of 976 differentially methylated regions (DMRs) (973 DMRs for CG and 3 DMRs for CHG) and 310 differentially methylated genes (DMGs) were identified in this study. Through integration of WGBS and RNA-Seq data, we identified 59 differentially methylated and differentially expressed genes (DEGs) and ultimately screened 8 key DMGs (9 DMRS) associated with litter size traits in Jining Grey goats (SERPINB2: chr24_62258801_62259000, NDRG4: chr18_27599201_27599400, CFAP43: chr26_27046601_27046800, LRP1B. chr2_79720201_79720400, EPHA6: chr1_40088601_40088800, TTC29: chr17_59385801_59386000, PDE11A: chr2_117418601_117418800 and PGF: chr10_ 16913801_16914000 and chr10_16916401_16916600). In summary, our research comprehensively analyzed the genome-wide DNAm profiles of HP and LP Jining Grey goat ovary tissues. The data findings suggest that DNAm in goat ovaries may play an important role in determining litter size.

Split weaning improves pregnancy rate and embryo survival in sows mated in lactation.

Increasing piglet weaning age while maintaining the reproductive efficiency of the breeding herd depends on the ability to stimulate sows to ovulate during lactation without reducing subsequent pregnancy rates and litter sizes. The aim of this study was to determine if a reduction in piglet suckling load, either prior to or immediately after mating in lactation, altered ovarian follicle development and increased embryo survival to day 30 of gestation. Fifty-nine multiparous Large White x Landrace sows were allocated to one of three treatments; litter size maintained at 11 piglets (control); litter size reduced to seven piglets on day 18 of lactation (split wean (SW)); or litter size reduced to seven piglets at expression of lactation oestrus (oestrus split wean (OES SW)). The percentage of sows that expressed lactation oestrus did not differ between treatments (79.7 %; P > 0.05) and split weaning had minimal effects on ovarian follicle development. Pregnancy rates were higher for SW and OES SW sows, compared to control sows. Embryo survival to day 30 of gestation was higher for SW sows (73.7 %) compared with control (56.4 %) and OES SW sows (49.5 %; P < 0.05). In summary, weaning a portion of the litter prior to mating in lactation improved pregnancy rates and embryo survival.

Heat stress from current and predicted increases in temperature impairs lambing rates and birth weights in the Australian sheep flock.

Livestock heat stress threatens production, particularly in semi-arid, arid and tropical regions. Using established temperature thresholds for sheep, we modelled +1 °C and +3 °C temperature increases over the historical baseline, estimating that 2.1 million potential lambs are lost annually due to heat stress alone, increasing to 2.5 and 3.3 million, respectively, as temperatures rise. Heat stress poses risks at key periods of the reproductive cycle, with consequences across the Australian sheep flock.

A repertoire of single nucleotide polymorphisms (SNPs) of major fecundity BMPR1B gene among 75 sheep breeds worldwide.

The BMPR1B gene is a major determinant of sheep reproductive capacity. Previous studies revealed that Q249R (FecB) is a profound variant of BMPR1B that influences the ovulation rate and litter size in sheep. However, unlike Q249R locus, the full spectrum of single nucleotide polymorphisms (SNPs) within BMPR1B has not been extensively studied. A systematic screen of SNPs in BMPR1B would facilitate the discovery of novel variants that are associated with litter size. This study aimed to investigate SNPs in the BMPR1B gene via whole genome sequence (WGS) data from 2409 individuals of 75 sheep breeds worldwide. Herein, a total of 9688 variants were screened, among which 15 were coding variants and 8 were novel changes. Specifically, we presented the most comprehensive frequency distribution map of the well-known FecB mutation to date. Besides, among the above-mentioned SNPs, one synonymous mutation (g.30050773C > T) was found to be likely under selection and is potentially associated with fecundity in Duolang sheep. Thus, our study greatly expands the variation repertoire of the ovine BMPR1B gene and provides a valuable resource for exploring causative mutations and genetic markers associated with litter size.

The novel C268A variant of BMP2 is linked to the reproductive performance of Awassi and Hamdani sheep.

BACKGROUND: Prolificacy-associated genetic markers can be utilized to enhance litter size in the sheep breeding industry. Sheep reproduction is influenced by a multitude of genes, including bone morphogenetic protein 2 (BMP2). This study aimed to explore the potential relationship between variability in the BMP2 gene and reproductive performance in Awassi and Hamdani ewes. METHODS AND RESULTS: The genomic DNA was extracted from 99 single-progeny ewes and 101 twin ewes. Polymerase chain reaction (PCR) was employed to produce an amplicon consisting of four sequence fragments: 277 bp, 251 bp, 331 bp, and 340 bp, from exons 1, 2, 3, and 4 of the BMP2 gene, respectively. Three genotypes were identified for amplicons in exon 4 with 340-bp lengths: CC, CA, and AA. Upon analyzing the sequence of the CA genotype 382 C > A, a novel mutation was discovered in this genotype. A robust association was identified between the single nucleotide polymorphisms (SNP) 382 C > A and reproductive performance through statistical analysis. An important distinction was discovered between ewes carrying SNP 382 C > A and those carrying CC in terms of litter sizes, twinning rates, lambing rates, and days to lambing. An analysis of logistic regression revealed a significant association between litter size and the 382 C > A SNP. There was a decrease in lamb production among ewes with the CC genotype compared to those with the CA and AA genotypes. CONCLUSIONS: These results indicate that the SNP variant 382 C > A has a positive influence on the reproductive performance of Awassi and Hamdani sheep. Sheep carrying the 382 C > A SNP exhibit increased litter size and overall productivity compared to those without the SNP.

Effects of a TAML catalyst on mice exposed during pregnancy and lactation.

Tetra-amido macrocyclic ligands (TAMLs) are catalysts designed to mimic endogenous peroxidases that can degrade pollutants. Before TAMLs gain widespread use, it is first important to determine if they have endocrine disrupting properties. In this study, we evaluated the effects of the iron TAML, NT7, on hormone-sensitive outcomes in mice exposed during pregnancy and lactation, and on their litters prior to weaning. We administered NT7 at one of three doses to mice via drinking water prior to and then throughout pregnancy and lactation. Two hormonally active pharmaceuticals, ethinyl estradiol (EE2) and flutamide (FLUT), a known estrogen receptor agonist and androgen receptor antagonist, respectively, were also included. In the females, we measured pre- and post-parturition weight, length of pregnancy, organ weights at necropsy, and morphology of the mammary gland at the end of the lactational period. We also quantified maternal behaviors at three stages of lactation. For the offspring, we measured litter size, litter weights, and the achievement of other developmental milestones. We observed only one statistically significant effect of NT7, a decrease in the percentage of pups with ear opening at postnatal day 5. This contrasts with the numerous effects of EE2 on both the mother and the litter, as well as several modest effects of FLUT. The approach taken in this study could provide guidance for future studies that aim to evaluate novel compounds for endocrine disrupting properties.

The influence of parity, body condition, litter size and carbetocin administration on colostrum production and immunoglobulin levels in highly productive sows within a tropical environment.

The aim of this study was to explore the factors contributing to colostrum production and the levels of colostrum immunoglobulins (IgG and IgA) in contemporary highly productive sows within a tropical climate. We focused on variables such as parity number, litter size, sow body condition score (BCS), the timing of sample collection following the commencement of farrowing and the use of carbetocin during the birthing process. A total of 100 colostrum samples were collected from a group of 50 Danish Landrace × Yorkshire crossbred sows. These samples were taken at two distinct time intervals: right after farrowing (0 h) and 6 h later. The colostrum samples were classified according to the sows' parity numbers, with 33 samples originating from primiparous sows and 67 from multiparous ones. Additionally, the number of live-born piglets were categorized into three groups: 7-13, 14-17 and ≥ 18 piglets per litter. Moreover, the samples were categorized based on the use of carbetocin during the birthing process, with 34 sows experiencing natural farrowing and 66 sows receiving carbetocin. The sow's BCS was assessed through visual evaluation and palpation. The piglet colostrum consumption and the amount of colostrum produced by the sows were determined. The concentrations of IgG and IgA were determined by using the enzyme-linked immunosorbent assay (ELISA) technique. On average, the colostrum production averaged 5.5 ± 1.7 kg, with IgG and IgA concentrations averaging 54.9 ± 24.6 mg/ml and 7.6 ± 3.5 mg/ml, respectively. Primiparous sows exhibited a significant 25.2% decrease in IgG concentration within 6 h of parturition (P < 0.05), whereas no such decline was observed in multiparous sows. Furthermore, multiparous sows displayed higher colostrum yields (6.2 ± 1.5 kg and 4.3 ± 1.5 kg, respectively, P < 0.001) and IgA concentrations compared to primiparous sows (8.3 ± 3.8 mg/ml and 6.3 ± 2.6 mg/ml, respectively, P = 0.002). Furthermore, a positive correlation was observed between IgA concentrations in colostrum and the sow's BCS at both the 0-h and 6-h post-farrowing time points (r = 0.425, P = 0.002 and r = 0.315, P = 0.031, respectively). The administration of carbetocin did not yield a significant impact on the concentrations of IgG and IgA in the sows' colostrum (P > 0.05). In conclusion, during the initial 6 h after birth, colostrum IgA levels remained stable, whereas there was a noticeable decline in IgG levels, particularly among primiparous sows. The production volume of colostrum and the concentration of IgA in sows within tropical conditions were influenced by both parity number and body condition score.

Impact of litter size on the hematological and iron status of gilts, sows and newborn piglets: a comparative study of domestic pigs and wild boars.

BACKGROUND: The critically low hepatic iron stores of newborn piglets are considered to be a major cause of neonatal iron deficiency in modern breeds of domestic pig (Sus domestica). The main factor believed to contribute to this phenomenon is large litter size, which has been an objective of selective breeding of pigs for decades. As consequence, iron transferred from the pregnant sow has to be distributed among a greater number of fetuses. RESULTS: Here, we investigated whether litter size influences red blood cell (RBC) indices and iron parameters in Polish Large White (PLW) piglets and gilts. Small and large litters were produced by the transfer of different numbers of embryos, derived from the same superovulated donor females, to recipient gilts. Piglets from large litters obtained following routine artificial insemination were also examined. Our results clearly demonstrated that varying the number of piglets in a litter did not affect the RBC and iron status of 1-day-old piglets, with all showing iron deficiency anemia. In contrast, gilts with small litters displayed higher RBC and iron parameters compared to mothers with large litters. A comparative analysis of the RBC status of wild boars (having less than half as many piglets per litter as domestic pigs) and PLW pigs, demonstrated higher RBC count, hemoglobin level and hematocrit value of both wild boar sows and piglets, even compared to small-litter PLW animals. CONCLUSIONS: These findings provide evidence that RBC and iron status in newborn PLW piglets are not primarily determined by litter size, and indicate the need to study the efficiency of iron transport across the placenta in domestic pig and wild boar females.

Genetic basis of sow hyperprolificacy and litter size optimization based on a genome-wide association study.

Over the last few decades, there has been a constant increase in sow litter size, the consequences of which include parturition duration extension, an increase in the percentage of stillborn and hypoxic piglets, and increased variation in piglet birth weight, which reduces their vitality. As such, it seems clear that further increasing sow fertility will generate difficulties and costs in rearing numerous litters with low birth weights. Therefore, the current study aimed to analyze the genetic background of sow hyperprolifcacy using a genome-wide association study (GWAS). The research included 144 sows in the maternal component, divided into two equal groups. The first group (control) consisted of females giving birth to the optimal number of piglets in their third and fourth litters (14-16), while the second group (cases) included those with excessive litter size (>16). The analyzed sows were genotyped using Illumina's PorcineSNP60v2 BeadChip microarray, comprising 64,232 single nucleotide polymorphisms (SNPs). Statistical analysis using R included quality control of genotyping data and GWAS analysis based on five logistic regression models (dominant, codominant, overdominant, recessive, and log-additive) with a single SNP marker as the explanatory variable. On this basis, one SNP (SIRI0000069) was identified on chromosome seven within the EFCAB11 (EF-hand calcium binding domain 11) gene that had a statistically significant effect on sow hyperprolificacy. Additionally, ten SNPs (INRA0007631, ALGA0011600, ALGA0043433, ALGA0043428, M1GA0010535 ALGA00443338, ALGA0087116, MARC0056787, ALGA0112928, and ALGA0089047) had a relationship with the analyzed feature at a level close to significance, set at 1-5. These SNPs appear important since they are located on chromosomes on which a large number of quantitative trait loci (QTLs) and SNPs associated with reproductive characteristics, including litter size, have been identified.

Lactation body condition loss impaired conceptus development and plasma progesterone concentration at day 8 post-ovulation in primiparous sows.

The current study investigated effects of dietary amino acid (AA) availability on lactational body condition loss and metabolic status, in relation to reproductive parameters after weaning up to Day 8 post-ovulation. Primiparous sows (n = 35) were allocated to one of two lactation diets containing either low crude protein (CP, 140 g/kg) with a low percentage (8%) of slow protein in total protein (LL, n = 18) or high CP (180 g/kg) with a high (16%) percentage of slow protein (HH, n = 17). The HH diet was expected to improve AA utilization by supplying more AA, in a more gradual fashion. The diets did not affect sow body condition loss during lactation, while the HH diet tended to increase litter weight gain during the week 3 of lactation (Δ = 1.3 kg, P = 0.09). On Day 14 post-farrowing, HH diet led to higher plasma urea both pre-feeding and post-feeding (Δ = 2.3 mmol/L, P < 0.01, Δ = 2.4 mmol/L, P < 0.01, respectively), whilst plasma creatinine, NEFA and IGF-1 were similar. No dietary effects on reproductive parameters were found, however several relationships were found between body condition and reproductive parameters. Sows with higher body weight on Day 1 or Day 21 post-farrowing had greater follicle size on Day 3 post-weaning (ß = 0.03 mm/kg, P < 0.01, ß = 0.04 mm/kg, P < 0.01, respectively). At Day 8 post-ovulation, plasma progesterone concentration was negatively related to loin muscle loss (ß = -0.67 ng/ml · mm-1, P = 0.02), backfat loss (ß = -2.33 ng/ml · mm-1, P = 0.02), and estimated body fat loss (ß = -0.67 ng/ml · mm-1, P = 0.02). Both plasma progesterone and the number of corpora lutea were positively related to the energy balance during lactation (ß = 0.03 ng/ml · ME MJ-1, P = 0.01, ß = 0.01 CL/ME MJ, P = 0.02, respectively). The conceptus size at Day 8 post-ovulation was negatively related to body weight loss (ß = -0.01 mm/kg, P = 0.01), estimated body fat loss (ß = -0.02 mm/kg, P = 0.03) and estimated body protein loss (ß = -0.06 mm/kg, P = 0.04), and was positively related to the energy balance during lactation (ß = 5.2*10-4 mm/ME MJ, P = 0.01). In conclusion, body protein and fat losses during lactation reduced subsequent plasma progesterone concentration and conceptus development at Day 8 post-ovulation.

Genetic variation in the BLM gene and its expression in the ovaries is closely related to kidding number in goats.

Bloom (BLM) helicase plays an important role in DNA replication and the maintenance of genome integrity. BLM protein deficiency, which plays a vital role in the sperm-egg union and germ-cell development during reproduction, can lead to severe DNA damage in goats. However, the effect of BLM protein deficiency on goat litter size has not been reported. Herein, we studied the association between the genetic variation in the BLM gene and the number of kids per litter in Guizhou white goats. We explored differences in the expression of the BLM protein in the follicles of single and multi-kid nanny goats. We also analyzed the effects of dysregulated BLM gene expression on the proliferation and apoptosis of ovarian granulosa cells and the expression of genes related to follicle development in goats. Five single nucleotide polymorphism (SNP) loci, including the non-synonymous mutations g.38179 A > G, g.40626 G > C and g.89621 T > G; the intron synonymous mutation g.56961 G > A and the exon synonymous mutation g.65796 C > T were found in the BLM gene. All SNPs loci were in Hardy-Weinberg equilibrium, and correlation analysis showed that the g.65796 C > T and g.89621 T > G loci polymorphism was strongly associated with litter size in the first three litters (P < 0.05). The diplogenotype Hap 2/2 (AAGGAACCTT) showed no significant difference in litter size between different births, indicating that the diploid genotype is stable in different litter sizes. Bioinformatics analysis showed that three non-synonymous mutation loci (p.T488A, p.A662S, and p.S1373A) could affect BLM protein stability, and mutations in p.T488A and p.S1373A led to changes in amino acid polarity and associated interactions. qPCR results showed that the expression level of the BLM gene in the uterus and ovaries of TT genotype nanny goats was significantly higher than that of GG genotype nanny goats. Indirect immunofluorescence assay (IF) showed that the BLM protein was significantly overexpressed in both the primordial and growing follicles of nanny goats with multiple kids (P < 0.01). Disrupting BLM gene expression in the ovarian granulosa cells down-regulated the expression of the Cyp19A1 gene. It also significantly inhibited the proliferation of follicles and induces early apoptosis of the granulosa cells. These findings confirm that polymorphism in the BLM gene is closely related to the littering traits of Guizhou white goats, and it affects the reproductive performance of nanny goats by regulating the development of the oocytes and granulosa cells. This work provides new evidence on the regulatory effect of the BLM gene on the litter size of nanny goats.

Effect of split weaning on follicle development and oocyte quality in multiparous sows.

Increasing piglet weaning age while maintaining the reproductive efficiency of the breeding herd depends on being able to stimulate sows to ovulate during lactation without reducing subsequent pregnancy rates and litter sizes. Embryo survival is affected by the quality of the oocytes shed at ovulation, and oocyte quality is profoundly impacted by the follicular environment in which the oocyte matures. This study determined the effect of reducing suckled litter size from 11 to 7 piglets on day 18 of lactation on the ovarian follicular environment and oocyte developmental competence at day 21 of lactation. Thirty-nine, Large White X Landrace sows (parity 3.2 ± 0.2; mean ± SEM; range 2-6) had their litter size either maintained at 11 piglets (control); or reduced to seven piglets on day 18 of lactation (split wean (SW)). Sows were slaughtered on day 21 of lactation and ovaries were collected for analysis of follicular fluid composition and in vitro blastocyst development rates. There was no effect of split weaning on fertilisation rate and development to blastocyst stage; however, a greater proportion of blastocysts from control sows were classified as early blastocyst stage. Furthermore, follicular fluid concentrations of oestradiol were higher in SW sows. Together, these results indicate split weaning prior to mating in lactation alters the ovarian follicular environment and while blastocyst development rates were unaffected, embryos from control sows may be of poorer quality as indicated by a delay in development.

Semen Protein CRISP3 Promotes Reproductive Performance of Boars through Immunomodulation.

Semen proteins play an important role in male reproductive performance and sperm fertilization ability and can be used as potential biomarkers to evaluate male fertility. The role of cysteine-rich secretory protein 3 (CRISP3) in male reproduction remains unknown. This study aimed to investigate the role of CRISP3 in the reproductive performance of boars. Our results showed that the CRISP3 protein content was significantly and positively correlated with boar fertility, sow delivery rate, and litter size. CRISP3 is highly expressed in the bulbourethral gland of adult boars and is enriched in the seminal plasma. It is localized in the post-acrosomal region of the sperm head and migrates to the anterior end of the tail after capacitation. The CRISP3 recombinant protein did not affect sperm motility and cleavage rate, but it significantly downregulated the mRNA expression of inflammatory factors IL-α, IL-1ß, and IL-6 and the protein expression of IL-α and IL-6 in lipopolysaccharide (LPS)-induced RAW264.7 cells, indicating that CRISP3 has an immunomodulatory function. In conclusion, our study suggests that semen CRISP3 protein levels positively correlate with reproductive performance, which may be achieved by regulating immune responses in the female reproductive tract.

Sow hematological parameters in late pregnancy and an investigation as to whether these parameters are predictors of stillbirths in a Canadian sow herd.

Animal and objective: The objectives of this study were to produce hematological reference intervals for late-pregnancy sows and to assess whether there were associations between sow hematological end points and the number of stillborn pigs. Procedure: Whole blood was collected from 272 healthy pregnant sows ~1 wk before farrowing, and complete blood (cell) counts and hemoglobin determinations were obtained. Sows were monitored during farrowing, and litter characteristics, including number of stillborn piglets, were recorded. Results and conclusion: Values for red blood cells, hemoglobin, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular concentration, platelets, and white blood cells were significantly higher in Parity 1 sows compared to older sows. The mean (± SD) litter size was 14.5 ± 3.4 pigs, with 1.5 ± 2.0 stillborn pigs per litter. There was no significant association between any hematological end point (except white blood cell counts) and the likelihood of a stillborn piglet in a litter. There was a relationship between parity and stillbirth (P < 0.05), with higher-parity sows being more likely than younger sows to produce a stillborn piglet. Although it had been reported that anemic sows were more likely to have stillbirths, perhaps the relatively high mean hemoglobin concentration of sows in this study resulted in the lack of a relationship.

Paramètres hématologiques des truies en fin de gestation et enquête visant à déterminer si ces paramètres sont des prédicteurs de mortinatalités dans un troupeau de truies canadien. Animal et objectif: Les objectifs de cette étude étaient de produire des intervalles de référence hématologiques pour les truies en fin de gestation et d'évaluer s'il existait des associations entre les paramètres hématologiques des truies et le nombre de porcelets mort-nés. Procédure: Du sang total a été collecté auprès de 272 truies gravides en bonne santé environ 1 semaine avant la mise bas, et une numération cellulaire complète et des déterminations d'hémoglobine ont été obtenues. Les truies ont été surveillées pendant la mise bas et les caractéristiques de la portée, y compris le nombre de porcelets mort-nés, ont été enregistrées. Résultats et conclusion: Les valeurs des globules rouges, de l'hémoglobine, du volume corpusculaire moyen, de l'hémoglobine corpusculaire moyenne, de la concentration corpusculaire moyenne, des plaquettes et des globules blancs étaient significativement plus élevées chez les truies de parité 1 que chez les truies plus âgées. La taille moyenne (± ET) des portées était de 14,5 ± 3,4 porcs, avec 1,5 ± 2,0 porcs mort-nés par portée. Il n'y avait aucune association significative entre un quelconque paramètre hématologique (à l'exception du nombre de globules blancs) et la probabilité d'avoir un porcelet mort-né dans une portée. Il y avait une relation entre la parité et la mortinatalité (P < 0,05), les truies ayant une parité plus élevée étant plus susceptibles que les truies plus jeunes de produire un porcelet mort-né. Bien qu'il ait été rapporté que les truies anémiques étaient plus susceptibles d'avoir des mortinatalités, la concentration moyenne d'hémoglobine relativement élevée des truies dans cette étude a peut-être entraîné l'absence de relation.(Traduit par Dr Serge Messier).

Detection of polymorphisms in six genes and their association analysis with litter size in sheep.

Litter size in sheep is a complex trait controlled by micro-effective polygenes. APAF1, CLSTN2, CTH, PLCB1, PLCB4, and CHST11 are all involved in mammalian reproduction. However, the effects of these genes on litter size in sheep are still unclear. Therefore, in this study, we used Sequenom MassARRAY® SNP assay technology to type the single nucleotide polymorphisms (SNPs) loci of six genes in five sheep breeds. The results showed that most sheep breeds contain three genotypes at each locus. Then, we conducted population genetic analysis on the SNPs of six genes and found that the polymorphic information content in all sheep breeds ranged from 0 to 0.37, and most sheep breeds were in Hardy-Weinberg equilibrium (p > 0.05). In addition, association analysis in Small Tail Han sheep indicated that the rs399534524 locus in CLSTN2 was highly associated with first parity litter size, and litter size in ewes with CT genotype was higher than that in ewes with CC genotype or TT genotype. Furthermore, the rs407142552 locus in CTH was highly associated with second parity litter size in Small Tail Han sheep, and litter size in ewes with CT genotype was higher than that in ewes with TT genotype. Finally, we predicted the CTH and CLSTN2 protein interaction network and found that HTR1E, NOM1, CCDC174 and ALPK3 interact with CLSTN2 and have been reported as candidate genes related to litter size in sheep. These results suggest that they may be useful genetic markers for increasing litter size in sheep.