Litter Size Research Articles

4D label-free quantitative proteomic analysis identifies CRABP1 as a novel candidate gene for litter size in rabbits†.

In commercial rabbit breeding, litter size is a crucial reproductive trait. This trait directly determines the reproductive ability of female rabbits and is crucial for evaluating the production efficiency. We here compared differentially expressed proteins of in the ovary tissue from New Zealand female rabbits with high (H) and low (L) litter sizes by using 4D label-free quantitative proteomic technology and identified 92 differential proteins. The biological functions of these proteins were revealed through gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Most distributions of GO and KEGG were related to reproduction, growth development, and metabolism. Furthermore, a novel candidate gene cellular retinoic acid binding protein-1 (CRABP1), which was highly expressed in the L group, was selected for further biological function verification. The Cell Counting Kit-8 (CCK-8) assay and flow cytometry analysis revealed that CRABP1 can promote granulosa cell (GC) apoptosis and inhibit GC proliferation. Furthermore, qRT-PCR and western blotting analysis revealed that CRABP1 regulates the genes (HSD17B1, Wnt-10b, FSHR, TAF4B, BMP15, and BMP6) and protein (Wnt-10b) associated with steroid hormone synthesis and follicle development. The PCR product direct sequencing method revealed single nucleotide polymorphisms in the core promoter region of CRABP1. Luciferase activity assays revealed that the transcriptional activity of the GG genotype was significantly higher than that of the TT or TG genotype. Different genotypes are accompanied by changes in transcription factors, which indicates that T-359G polymorphism can regulate CRABP1 expression. In general, we identified litter size-related genes and revealed the mechanism underlying the effect of CRABP1 on litter size. CRABP1 serves as a key factor in the reproductive capacity of rabbits and can act as a molecular biomarker for the breeding of New Zealand rabbits.

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.

EFECTO DEL TAMAÑO DE CAMADA EN PRIMER PARTO Y SEGUNDO PARTO SOBRE LA PRODUCTIVIDAD ACUMULADA DE LAS CERDAS, EN UNA GRANJA COMERCIAL DE YUCATÁN, MÉXICO

<p><strong>Background.</strong> Litter size reduction at second farrowing (RSP) affects cumulative productivity per productive life of sows. <strong>Objective.</strong> To compare groups of sows according to their classification by number of piglets born alive (LNV) at first farrowing and reduction or increase of LNV at second farrowing on the number of farrowings at culling (NPD), cumulative LNV and weaned per productive life of sows in a commercial farm in the eastern zone of Yucatan, Mexico. <strong>Methodology</strong>. Data from 404 culled sows were used. Six groups of sows were established: low number of LNV at first farrowing with RSP (B-RSP), low with increased number of LNV at second farrowing (B-ISP), medium with RSP (M-RSP), medium with ISP (M-ISP), high with RSP (A-RSP) and high with ISP (A-ISP). The response variables were NPD, cumulative piglets born alive during the productive life of the sows (LNVP) and cumulative piglets weaned during the productive life of the sows (LDVP). <strong>Results.</strong> No difference was found between the different sow groups for NPD and LDVP (P>0.05). The lowest number of LNVP was obtained in sows of groups B-RSP and B-ISP (P<0.05). <strong>Conclusion.</strong> Under the conditions of this study, NPD and LDVP of sows during their stay on the farm were not affected by RSP or ISP. LNVP was not affected by reduction or increase of piglets at second farrowing in sows with small litters at first farrowing.</p>

Unveiling the Ovarian Cell Characteristics and Molecular Mechanism of Prolificacy in Goats via Single-Nucleus Transcriptomics Data Analysis.

Increases in litter size, which are influenced by ovulation, are responsible for between 74% and 96% of the economic value of genetic progress, which influences selection. For the selection and breeding of highly prolific goats, genetic mechanisms underlying variations in litter size should be elucidated. Here, we used single-nucleus RNA sequencing to analyze 44,605 single nuclei from the ovaries of polytocous and monotocous goats during the follicular phase. Utilizing known reference marker genes, we identified 10 ovarian cell types characterized by distinct gene expression profiles, transcription factor networks, and reciprocal interaction signatures. An in-depth analysis of the granulosa cells revealed three subtypes exhibiting distinct gene expression patterns and dynamic regulatory mechanisms. Further investigation of cell-type-specific prolificacy-associated transcriptional changes elucidated that "downregulation of apoptosis", "increased anabolism", and "upstream responsiveness to hormonal stimulation" are associated with prolificacy. This study provides a comprehensive understanding of the cell-type-specific mechanisms and regulatory networks in the goat ovary, providing insights into the molecular mechanisms underlying goat prolificacy. These findings establish a vital foundation for furthering understanding of the molecular mechanisms governing folliculogenesis and for improving the litter size in goats via molecular design breeding.

Impacts of Fiber Supplementation in Sows during the Transition Period on Constipation, Farrowing Duration, Colostrum Production, and Pre-Weaning Piglet Mortality in the Free-Farrowing System.

This study investigated how dietary fiber supplementation during the transition period in sows affects constipation, farrowing duration, colostrum production, milk yield, and pre-weaning piglet mortality in the free-farrowing system. A total of 92 Landrace × Yorkshire sows and their 1272 offspring were included in the study. Sows were divided into two groups by parity: control (n = 41) and treatment (n = 51). The control group was fed a standard lactation diet 7 days before farrowing, whereas the treatment group received the same diet with 75 g/day of a dietary fiber supplement. The dietary fiber content analyses were 4.30% and 5.53% in the control and treatment groups, respectively. Sows were fed with 3.89 ± 0.92 kg per day with a diet containing 17.8% crude protein, 3732 kcal/kg of metabolizable energy, and 1.1% lysine. Parameters including farrowing duration, litter characteristics, and the fecal condition of sows were measured. Piglet mortality rates were recorded at 3, 7, and 21 days of lactation. Sows had an average farrowing duration of 216 ± 159 min, with litter sizes of 13.8 ± 4.2 piglets per litter, and a 7.4% stillbirth rate. The treatment group showed a lower constipation rate compared to the control group (17.6% vs. 46.3%, p = 0.003). Farrowing duration did not significantly differ between groups, but the treatment group experienced a 43.6 min shorter duration. In sows with litter sizes of ≥16 piglets per litter, the farrowing duration for sows in the treatment group tended to be shorter than that of the control groups (202.0 ± 37.9 vs. 287.5 ± 41.3 min, p = 0.115). The mean colostrum intake of piglets in the control and treatment groups averaged 424.0 ± 13.7 g and 421.8 ± 12.6 g, respectively (p = 0.908). Likewise, the milk production of sows from Days 3 to 10 and from Days 10 to 17 of lactation in the treatment group (7.34 ± 0.27 and 8.76 ± 0.43 kg/day, respectively) did not differ from that of the control group (7.85 ± 0.30 and 9.55 ± 0.47 kg/day, respectively, p > 0.05). Pre-weaning piglet mortality was slightly lower in the treatment group (13.4% vs. 17.3%, p = 0.085). Across groups, piglet mortality rates within 3, 7, and 21 days were 10.3%, 11.9%, and 15.4%, respectively. Piglets with a ≤200 g colostrum intake had a higher pre-weaning mortality compared to those with a higher intake (p < 0.05), except for the 201-300 g intake (p = 0.472). In conclusion, introducing dietary fiber to sows during the transition period reduced constipation and tended to decrease farrowing duration, especially in sows with large litters. Additionally, it lowered pre-weaning piglet mortality by 3.9% in the free-farrowing system. Nonetheless, providing sows with a 75 g/day dietary fiber supplement for only 7 days before farrowing was not enough to enhance colostrum and milk production, nor did it lead to an increase in piglet colostrum consumption.

Association between polymorphisms in NOBOX and litter size traits in Xiangsu pigs.

The newborn ovary homeobox gene (NOBOX) regulates ovarian and early oocyte development, and thus plays an essential role in reproduction. In this study, the mRNA expression level and single nucleotide polymorphism (SNP) of NOBOX in various tissues of Xiangsu pigs were studied to explore the relationship between its polymorphism and litter size traits. Also, bioinformatics was used to evaluate the effects of missense substitutions on protein structure and function. The results revealed that NOBOX is preferentially expressed in the ovary. Six mutations were detected in the NOBOX sequence, including g.1624 T>C, g.1858 G>A, g.2770 G>A, g.2821 A>G, g.5659 A>G, and g.6025 T>A, of which g.1858 G>A was a missense mutation. However, only g.1858 G>A, g.5659 A>G, and g.6025 T>A were significantly associated with litter size traits (p < 0.05). Further prediction of the effect of the missense mutation g.1858 G>A on protein function revealed that p.V82M is a non-conservative mutation that significantly reduces protein stability and thus alters protein function. Overall, these findings suggest that NOBOX polymorphism is closely related to the litter size of Xiangsu pigs, which may provide new insights into pig breeding.

Impaired fertility in adenomyosis: a murine model reveals endometrial receptivity and progesterone resistance imbalances.

The impact of adenomyosis on reproductive health needs to be fully understood. By using a murine model, this study provides novel insights into the nuanced mechanisms associated with fertility challenges and offers a foundation for targeted interventions. This study investigates the intricate relationship between adenomyosis and reproductive health using a murine model, offering novel insights into this prevalent gynecological disorder. Adenomyosis, characterized by the invasive growth of endometrial tissue into the myometrium, is believed to negatively impact fertility. However, the challenge lies in disentangling this influence, as adenomyosis often coexists with other gynecological diseases. A tamoxifen-induced mice model presents a significant advantage by enabling the specific study of adenomyosis, devoid of confounding influences of concurrent gynecological diseases such as endometriosis. Focusing exclusively on adenomyosis, our study aims to elucidate pathogenic mechanisms underlying fertility issues, focusing on estrous cyclicity, ovarian follicle development, and overall fertility. Our findings uncover disruptions in estrous cyclicity, characterized by an increased duration of time spent in the estrus phase in adenomyosis-induced mice. These disturbances are potentially linked to observed compromised folliculogenesis and the remarkable reduction in litter number and size in mice affected by adenomyosis. Moreover, this study unveils potential drivers of subfertility such as progesterone resistance and altered endometrial receptivity. Within the uteri of mice with adenomyosis, reduced expression of the progesterone receptor and a decreased expression of two implantation-related markers (HoxA10 and integrin β3) were observed. This comprehensive examination sheds light on the nuanced complexities of adenomyosis-associated reproductive challenges, providing a foundation for targeted interventions in addressing fertility issues related to this disease.

Taxonomic, phylogenetic, and functional nestedness of mammal assemblages in the Zhoushan Archipelago, China

Abstract Nestedness is an important part of the theoretical framework of island biogeography and community ecology. However, most previous studies focused on taxonomic dimension and overlooked functional and phylogenetic nestedness. Here, we simultaneously investigated taxonomic, functional, and phylogenetic nestedness of terrestrial mammals on 39 land-bridge islands in the Zhoushan Archipelago, China. As mammals’ response to the environment may depend on their body size, we performed analyses for three mammal assemblages separately: overall species, large and medium-sized species, and small species. The taxonomic nestedness was quantified by organizing the species incidence matrix, while the functional and phylogenetic nestedness were estimated by combining the similarity of their ecological traits and phylogeny. Island characteristics (island area, three isolation indices, land use intensity, and habitat diversity) and species traits (body size, litter size, habitat specificity, geographic range size, and minimum area requirement) were used as predictors of nestedness. Overall and small species were significantly nested in 3 facets of nestedness, and results supported the selective extinction, selective colonization, and habitat nestedness hypotheses. Large and medium-sized species were functionally and phylogenetically nested when matrices were ordered by increasing distance to mainland, supporting the selective colonization hypothesis. Overall, differences in nestedness and its underlying mechanisms were detected not only in 3 facets of nestedness but also in the 3 mammal assemblages. Therefore, frameworks that incorporate taxonomic, phylogenetic, and functional nestedness can contribute to a more comprehensive understanding of nestedness processes. Additionally, it also improves our ability to understand the divergent responses of mammal assemblages to the insular environment.

Early postnatal moderate catch‑up growth in rats with nutritional intrauterine growth restriction preserves pulmonary vascular and cognitive function in adulthood.

Intrauterine growth restriction (IUGR) with rapid postnatal catch-up growth is strongly associated with pulmonary vascular dysfunction in adulthood, whereas IUGR with delayed growth in early postnatal life results in long-term brain deficits. In the present study, it was hypothesized that IUGR with early moderate catch-up growth may alleviate pulmonary vascular remodeling in adulthood without affecting memory function. An IUGR model was established by restricting maternal nutrition during pregnancy. Different growth patterns were achieved by adjusting the litter size in each group during lactation. Rats meeting the weight requirement at weaning were selected for subsequent studies at three time points (3, 9 and 13 weeks). Cognitive function was evaluated using a Y-maze. Invasive hemodynamic measurements were conducted to measure the mean pulmonary arterial pressure (mPAP). In addition, primary pulmonary artery smooth muscle cells (PASMCs) and pulmonary vascular endothelial cells (PVECs) were cultured to investigate their role in the increase in mPAP following rapid catch-up growth. The results showed that memory function deficits in the rats in the delayed growth group were associated with reduced proliferation of neural stem cells in the subgranular zone of the hippocampus. Furthermore, moderate catch-up growth at the three time points improved memory function while maintaining a normal mPAP. In adult IUGR rats experiencing rapid catch-up growth, although memory function improved, elevated mPAP and medial thickening of pulmonary arterioles were observed. Additionally, PASMCs exhibited excessive proliferation, migration and anti-apoptotic activity in the rapid catch-up group, and PVECs also displayed excessive proliferation. These results suggested that moderate catch-up growth after IUGR is a better strategy for optimal cognition and cardiovascular health in adulthood compared with rapid catch-up growth or delayed growth.

Heterothermy use in winter is associated with reduced litter size during following breeding season

Heterothermy is considered to be the most effective energy-saving strategy improving survival under natural conditions. Interspecific studies suggest that this strategy is also associated with reduced reproductive output. Yet little is known about the reproductive consequences of heterothermy use at the intraspecific level and thus its repercussions for microevolutionary processes. Moreover, as yet no study has aimed to test if litter size and juvenile mass are affected by torpor use in wild captured animals under undemanding laboratory conditions. Here we tested the hypothesis that intraspecific variation in heterothermy use is associated with different reproductive successes, being the result of the evolution of distinct life histories. We predicted that heterothermy use in winter negatively correlates with litter size and juvenile body mass during the subsequent breeding season. To test this prediction, we used yellow-necked mice from a population in which individuals consistently differ in their use of heterothermy in winter. We measured body size (head width) and body mass, basal metabolic rate, as well as metabolism and body temperature during fasting-induced torpor in wild caught mice in winter. Phenotyped mice were bred in the subsequent summer selectively – males and females with similar heterothermy characteristics were paired, the most to the least heterothermic. Dam body size, but not basal metabolism, was positively correlated with litter size (but not juvenile mass). However, when accounting for this relationship, litter size was negatively while juvenile mass was positively correlated with the average heterothermy use of a given couple. Our study indicates that heterothermy use correlates with specific life-history strategies arising from a fundamental evolutionary trade-off between survival and reproduction.

Deciphering Estrus Expression in Gilts: The Role of Alternative Polyadenylation and LincRNAs in Reproductive Transcriptomics.

The fertility rate and litter size of female pigs are critically affected by the expression of estrus. The objective of this study was to elucidate the regulatory mechanisms of estrus expression by analyzing the differential expression of genes and long intergenic non-coding RNAs (lincRNA), as well as the utilization of alternative polyadenylation (APA) sites, in the vulva and vagina during the estrus and diestrus stages of Large White and indigenous Chinese Mi gilts. Our study revealed that the number of differentially expressed genes (DEG) in the vulva was less than that in the vagina, and the DEGs in the vulva were enriched in pathways such as "neural" pathways and steroid hormone responses, including the "Calcium signaling pathway" and "Oxytocin signaling pathway". The DEGs in the vagina were enriched in the "Metabolic pathways" and "VEGF signaling pathway". Furthermore, 27 and 21 differentially expressed lincRNAs (DEL), whose target genes were enriched in the "Endocrine resistance" pathway, were identified in the vulva and vagina, respectively. Additionally, we observed that 63 and 618 transcripts of the 3'-untranslated region (3'-UTR) were lengthened during estrus in the vulva and vagina, respectively. Interestingly, the genes undergoing APA events in the vulva exhibited species-specific enrichment in neural or steroid-related pathways, whereas those in the vagina were enriched in apoptosis or autophagy-related pathways. Further bioinformatic analysis of these lengthened 3'-UTRs revealed the presence of multiple miRNAs binding sites and cytoplasmic polyadenylation element (CPE) regulatory aspects. In particular, we identified more than 10 CPEs in the validated lengthened 3'-UTRs of the NFIX, PCNX4, CEP162 and ABHD2 genes using RT-qPCR. These findings demonstrated the involvement of APA and lincRNAs in the regulation of estrus expression in female pigs, providing new insights into the molecular mechanisms underlying estrus expression in pigs.

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

β-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.

72 Comparison of Myotonic, Kiko, and Spanish Sires for Meat Goat Doe-Kid Traits

Abstract Myotonic goats are a small-framed heritage breed known for the condition myotonia congenita which causes a prolonged contraction of their muscles when startled. There is a potential for them to be utilized in commercial meat goat systems within the United States. This study evaluated the effect of Myotonic sires on kid preweaning and doe reproductive traits across a 2-yr period. Myotonic (n = 6) and Kiko (n = 5) sires were bred to a group of 72 Kiko-influenced does and produced 139 kids. Myotonic (n = 6) and Spanish (n = 4) sires were bred to a group of 53 Spanish-influenced does and produced 123 kids. Sire breed comparisons were made within doe group. Kids were weighed at birth and weaning (3 months of age). Within both doe groups, litter size affected (P &amp;lt; 0.05) weaning weight but not birth weight, whereas kid sex influenced (P &amp;lt; 0.05) both birth and weaning weights. Doe age affected (P &amp;lt; 0.05) birth and weaning kid weights in the Kiko group but did not influence (P &amp;gt; 0.05) kid weights within the Spanish group. Myotonic- and Kiko-sired kids did not differ (P &amp;gt; 0.05) for birth (2.81 ± 0.11 vs 2.81 ± 0.11 kg, respectively) and weaning (16.43 ± 0.65 vs. 16.92 ± 0.61 kg, respectively) weights. Likewise, Myotonic- and Spanish-sired kids did not differ (P &amp;gt; 0.05) for birth (2.66 ± 0.13 vs. 2.89 ± 0.13 kg, respectively) and weaning weights (14.96 ± 0.62 vs. 15.37 ± 0.61 kg, respectively). There was no effect (P &amp;gt; 0.05) of sire breed on ADG and survivability among kids within either doe group. Doe age did not influence (P &amp;gt; 0.05) litter weight at birth but did influence (P &amp;lt; 0.05) litter weight at weaning within the Kiko group. Doe age had no effect (P &amp;gt; 0.05) on these litter traits within the Spanish group. Myotonic and Kiko sires did not differ (P &amp;gt; 0.05) for birth (4.09 ± 0.25 vs. 4.43 ± 0.25 kg, respectively) and weaning (23.66 ± 1.51 vs. 23.69 ± 1.50 kg, respectively) litter weights. Litter weight at birth did not differ (P &amp;gt; 0.05) for Myotonic and Spanish sires (4.09 ± 0.15 vs. 4.44 ± 0.15 kg, respectively). Myotonic sires produced lighter (P &amp;lt; 0.05) litters at weaning than Spanish sires (21.10 ± 0.79 vs. 23.61 ± 0.92 kg). Service sire breed did not influence (P &amp;gt; 0.05) litter size at birth and weaning nor kidding and weaning rates within either doe group. Sire breed did not consistently affect preweaning kid traits nor doe reproductive traits. Myotonic sires did not significantly reduce birth and weaning kid weights compared with Kiko and Spanish sires in this preliminary study.

46 Use of soy hull as a supplement during late gestation and lactation for landrace hair sheep ewes in a forage-based system

Abstract Forage-based production systems can be limiting in providing adequate nutrition as the result of seasonal fluctuations in forage quality and quantity, especially during periods of increased nutritional demands such as late gestation and lactation. This study evaluated the use of an agro-byproduct supplementation (soy hull) to fill these demands. Barbados Blackbelly (BB) and St. Croix (STX) hair sheep ewes were bred November 1 in a 25-d breeding season in two single-sire groups to like breed sires, and initially managed as one group. Pregnant ewes (n = 36) were allocated, balanced by breed, parity and fetal numbers to either a corn/soybean (CS) or soy hull (SH) supplementation starting the last trimester of pregnancy. Ewes rotationally grazed predominantly fescue pastures subdivided into 6 sections (0.13 ha) using electro-netting (3 sections of 6 ewes per supplement type). Ewes were supplemented at either 0.75% BW (late gestation) or 1.5% BW (lactation) using a single group feeder per section. Ewes lambed on pasture and lambs were weaned at approximately 63 d. Lambs had access to the supplement provided to their dams. Data were collected on ewe BW changes and reproductive performance, and analyzed in a model with supplement type and breed as main effects. Results are presented as LSM. Supplement type had no effect on ewe prepartum (54.7 kg), postpartum (47.3 kg) and weaning BW (44.7 kg), whereas BW was consistently heavier in STX than BB ewes. Ewe late gestation (61 g/d) and lactation ADG (-51 g/d) were not affected by supplement type though breeds differed (P &amp;lt; 0.01) in lactation ADG (BB: -14 vs STX: -78 g/d). Lambing performance was also not affected by supplement type with 1.97 lambs born live, and 1.69 lambs weaned per ewe. There was a supplement type by breed interaction (P &amp;lt; 0.05) for number of lambs weaned with STX ewes receiving SH having a larger litter size at weaning than ewes receiving CS (1.40 vs. 2.10 lambs per ewe) with no difference in BB ewes (1.71 vs. 1.50 lambs per ewe, respectively). Neither litter birth (6.14 kg) and weaning weights (19.9 kg) nor litter ADG (233 g/d) were affected by supplement type. Litter BW was significantly greater (P &amp;lt; 0.01) in STX than BB (6.85 vs 5.18 kg), but not different at weaning. Lamb birth and weaning weights were not affected by supplement type, though preweaning ADG tended (P &amp;lt; 0.1) to be greater in CS than SH (162 vs. 142 g/d). Data indicate that substituting SH for a more traditional corn-based supplement in landrace hair sheep ewes managed in a pasture-based system did not affect ewe growth, reproductive performance, and lamb performance. Agro-byproduct supplementation should be explored further for use in sustainable, forage-based sheep production systems.

74 Effect of grazing native warm season grasses on parasitism and growth in weaned Katahdin lambs

Abstract Parasitism in lambs during the post-weaning period has effects on growth, survival, and sheep enterprise profitability. Opportunities to minimize exposure to infective larvae during this period may reduce clinical effects and improve lamb performance. Native warm season grasses (NWSG) offer increased growth during summer months and taller plants that allow grazing at greater heights. The objective here was to evaluate NWSG as a forage for post-weaning development of lambs in spring lambing, forage-based systems. Over 2 yr, Katahdin lambs (Yr 1, n = 30; Yr 2, n = 31) were managed at a producer farm in the piedmont region of North Carolina. Beginning 2 wk post-weaning, lambs were randomly assigned to graze on either NWSG (Big Bluestem and Indiangrass) or cool season grass (CSG, Kentucky 31 Tall Fescue base) pasture. Lambs were continuously grazed for 70 d in Yr 1 and 55 d in Yr 2. Fecal egg count (FEC), FAMACHA score, and body weight (BW) were measured every two weeks. Lambs were dewormed at FAMACHA ≥ 3. Forage analysis was conducted at the start and end of the grazing period. Statistical analysis were performance using the PROC Mixed procedure of SAS. Lambs in each group were raised in similar litter sizes and sire and sex were evenly distributed between groups. Fecal egg count and growth estimated breeding values (EBV) were similar between NWSG and CSG groups. In Yr 1 and 2, no differences were observed in FEC between grazing groups (P &amp;gt; 0.05). However, FEC did increase in both groups throughout the grazing period (P &amp;lt; 0.05). In Yr 1, no differences were observed in total BW gain (P = 0.74). However, in Yr 2, lambs grazing CSG had greater total BW gain than the NWSG group (P &amp;lt; 0.05). In both years, there were no differences in the percentage of lambs requiring deworming (Yr 1, P = 0.36; Yr 2, P = 0.47) but lambs requiring treatment had greater FEC EBVs (P &amp;lt; 0.05). Nutrient quality of NWSG pasture was reduced compared with CSG pastures. Total digestible nutrients and crude protein were less in NWSG compared with CSG pastures (Yr 2: 61.5% vs. 63.9% and 8.9% vs. 13.6%, respectively) and neutral detergent fiber was greater (Yr 2: 74.1% vs. 65.2%, respectively) resulting in decreased nutrient availability for NWSG group. While NWSG may provide additional biomass for summer grazing, rapid maturity rates may limit nutrient availability for lambs resulting in decreased growth performance despite similar levels of parasitism. Lamb FEC EBV may have a role in parasite resistance and deworming requirements regardless of forage type. Thus, genetics must be considered along with grazing management as part of an integrated parasite management plan.

Multilayer perceptron and support vector regression models for feline parturition date prediction

A crucial challenge in feline obstetric care is the accurate prediction of the parturition date during late pregnancy. The classic simple linear regression (SLR) model, which employed the fetal biparietal diameter (BPD) as the single input feature, was frequently applied for such prediction with limited accuracy. Since Multilayer Perceptron (MLP) and Support Vector Regression (SVR) are now two of the most potent scientific regression models, this study, for the first time, introduced such models as the new promising tools for feline parturition date prediction. The following features were candidate inputs for our models: biparietal diameter (BPD), litter size, and maternal weight. We observed and compared the performance results for each model. As the best-performed model, MLP delivered the highest coefficient score (0.972 ± 0.006), lowest mean absolute error score (1.110 ± 0.060), and lowest mean squared error score (1.540 ± 0.141), respectively. For the first time in this study, BPD, litter size, and maternal weight were considered the essential features for the innovative MLP and SVR modeling. With the optimized model parameters and the described analytical platform, further verification of these advanced models in feline obstetric practices is feasible.

Apgar scores in puppies following the induction of etomidate compared with alfaxalone or propofol for cesarean section.

The Apgar score is a useful assessment of neonatal viability in dogs. The Apgar score in puppies born by cesarean section can be lower than vaginal delivery because all anesthetic drugs can cross the placenta. Therefore, anesthetic drugs with minimal cardiorespiratory effect and rapid elimination are recommended for cesarean section. The present study aimed to compare Apgar scores in puppies born after the induction of etomidate, alfaxalone or propofol, and those maintained with isoflurane inhalation during cesarean section. Thirty-six bitches were equally divided in the three anesthetic drug groups. Modified Apgar scores were assessed at 5, 15, and 60 min after delivery. Intraoperative vital signs and Apgar scores were compared using a linear mixed model and adjusted pairwise comparisons using Bonferroni analysis. A total of 125 puppies were included in this study. Age, body weight, litter size, type of surgery, delivery time, anesthetic and surgical duration, and intraoperative vital signs did not significantly differ between the groups. Puppies in the alfaxalone and propofol groups had significantly higher Apgar scores than the etomidate group in both elective and emergency surgery. In elective surgery, Apgar scores at 5 min after delivery did not differ significantly between groups. At 15 and 60 min after delivery, Apgar scores in the etomidate group were significantly lower than those in the other groups. In emergency surgery, Apgar scores were significantly lower in the etomidate group than in the alfaxalone group at all time points. Induction with alfaxalone and propofol resulted in better outcomes with higher Apgar scores and neonatal viability than etomidate. Therefore, alfaxalone and propofol should be used as anesthetic induction drugs in both elective and emergency cesarean sections.

Disrupting Maternal Behavior and Inducing Cannibalism Due to Valproic Acid: An Unexplored Insight.

Valproic acid (VPA) is the most widely used chemical to develop the preclinical model of autism spectrum disorder (ASD). However, in addition to inducing autism, it causes different teratogenic effects like teeth malformation, tail kink, and abnormal body growth in offspring. So far, no study has explored VPA-induced maternal misbehavior, miscarriage, and maternal cannibalism. We aimed to determine the cannibalistic effects of VPA in pregnant female Wistar rats and VPA's influence on causing miscarriage frequency. Our study was conducted on pregnant Wistar rats. On gestation day (GD) 12.5, they were treated with VPA (600 mg/kg intraperitoneal) dissolved in saline at 250 mg/mL concentration. The observations were mean litter size, mean male/female pups, mean mortality, maternal cannibalism, mean number of pups alive, cannibalism of malformed pups, miscarriage, survival analysis of pups, and odds and risk ratio were calculated for deaths observed in both study (control and VPA-treated) groups. The study was conducted till the weaning period. VPA-exposed pregnant females portrayed significantly decreased litter size (P<0.0001), significantly higher cannibalistic behavior (P=0.0023), and significantly higher cannibalism of malformed pups (P=0.0484) than the control group. VPA had caused complete pregnancy loss (miscarriage) in 5 pregnant females. Moreover, the VPA group's mortality percentage (P=0.0019) was significantly higher than the control group. Overall, VPA has marked teratogenic effects (anatomical and morphological changes in offspring) with maternal behavior disruption, which causes cannibalism in Wistar female rats. The current manuscript findings can aid in investigating the novel mechanisms involved in maternal behavior disruption during the development of the VPA autism model.

Screening of Litter-Size-Associated SNPs in NOX4, PDE11A and GHR Genes of Sheep.

In previous studies, NOX4, PDE11A and GHR genes have been screened as important candidate genes for litter size in sheep by using the GWAS method; however, neither their effects on litter size nor the loci associated with litter size have been identified. In this study, three candidate loci (c.1057-4C > T in NOX4, c.1983C > T in PDE11A and c.1618C > T in GHR) were first screened based on our previous resequencing data of 10 sheep breeds. After the three loci were genotyped using Sequenom MassARRAY technology, we carried out population genetics analysis on the three loci and performed association analysis between the polymorphism of the three loci and the litter size of sheep. The results of population genetics analysis suggested that c.1057-4C > T in NOX4 and c.1983C > T in PDE11A may be subject to natural or artificial selection. The results of association analysis indicated that litter size was significantly associated with c.1057-4C > T in NOX4 and c.1983C > T in PDE11A (p < 0.05) in Small Tail Han sheep, and there was no significant interaction effect between the two loci on the litter size. In summary, c.1057-4C > T in NOX4 and c.1983 C > T in PDE11A can be considered candidate molecular markers for improving litter size in sheep.

Astragalus root increases Treg and Th17 involvement in embryo implantation and pregnancy maintenance by decreasing CTLA-4+ Tregs.

Maintenance of pregnancy is highly dependent on the maternal immune system. High levels of regulatory T cells (Tregs) accumulate in the maternal placenta to suppress immunoreactivity against fetal antigens. We assessed whether Astragalus root (AsR) and AsR-containing Kampo medicines modulate immunoreactivity and thereby increase mouse litter size. AsR-exposed murine splenocytes exhibited significantly increased IL-2 secretion. In AsR-exposed mice, total Tregs were significantly increased, whereas cytotoxic T lymphocyte antigen 4 (CTLA-4)-positive Tregs were decreased in AsR-exposed mice. Tregs express IL-2 receptor subunit alpha and are activated by IL-2. CTLA-4 interacts with B7 expressed in antigen-presenting cells (APCs) with high affinity, and CTLA-4/B7 signaling plays a critical role in inhibiting APC activity, thereby suppressing CD4+ T cell proliferation and activation. The decrease in CTLA-4+ Tregs in AsR-exposed mice is thought to induce an increase in CD4+ T cells, leading to increased IL-2 secretion from CD4+ T cells followed by Treg activation. Th17 cells prevent trophoblast apoptosis, resulting in trophoblast invasion into the decidua. AsR increases Th17 cells, thereby inducing dose-dependent increases in litter size. Although Keishikaogito (KO)- and Ogikenchuto (OK)-exposed mice exhibited increased IL-2 secretion and splenic Tregs, KO also increased CTLA-4+ Tregs. Therefore, KO promoted immunosuppression by increasing CTLA-4+ Tregs, which induced a decrease in Th17 and exerted little effect on litter size. Therefore, an increase in both Tregs and Th17 cells can be considered necessary for embryo implantation and pregnancy maintenance.