Search

Allotriploid oysters between Crassostrea gigas and C. angulata have been utilized in commercial culture in China. The prevalence of this allotriploids is attributed to fast growth and extensive temperature adaptability, however its drawbacks are low meat ratio and slightly restored fecundity. To tackle these problems, two types of allotetraploids were produced in a previous study. Here, a comparative assessment of the growth, survival and reproductive traits was made for genetically improved allotriploids (based on allotetraploids), traditional allotriploids, and autotriploids (C. gigas and C. angulata). The results showed that the survival rates of larvae for all crosses were >80% on day 15. Genetically improved allotriploids survived better than autotriploids during juvenile and adult stages. The whole weights, wet meat weights, and meat ratios of genetically improved allotriploids were larger than traditional allotriploids on day 390 and day 510. The condition indexes, infertile percentages and fecundity of genetically improved allotriploids were lower than C. gigas autotriploids but higher than that of traditional allotriploids. At the end of the experiment, genetically improved allotriploids (GIT1) had the largest yield (56.79 kg) among all the six crosses. Overall, this study demonstrated that GIT1 exhibited superior growth and survival characteristics, as well as higher sterility compared with traditional allotriploids, which could be used as a potential variety in northern China. • The genetically improved allotriploid oysters GIT1 survived better than autotriploids. • The total weights, wet meat weights, and meat ratios of GIT1 were larger than traditional allotriploids. • The condition indexes, infertile percentages and fecundity of GIT1 were higher than that of traditional allotriploids. • At harvest, GIT1 had the largest yield among all crosses. • The genetically improved allotriploids GIT1 can be used as a potential variety for oyster industry. [ABSTRACT FROM AUTHOR]

The ability of dry forests to deliver ecosystem services of both local and global relevance depends on the capacity of those forests to recover from constant disturbances in human-modified landscapes. Here we examine the effects posed by biomass, chronic human disturbances and aridity on the recovery of reproductive functional diversity by edible fruit plant assemblages following slash-and-burn agriculture in a Caatinga dry forest, in northeastern Brazil. The edible fruit plant assemblages were described across 24 forest stands, including regenerating stands of varying age (4 to 50 yr old) and old-growth stands, adopting a large set of reproductive traits as floral sizes, reproductive systems, and pollination systems. Such a chronosequence covered a gradient relative to aboveground biomass, aridity, and chronic anthropogenic disturbances (CAD). We observed that edible fruit plant assemblages across both regenerating and old-growth forest stands exhibited similar taxonomic diversity scores. This pattern is also figured in the recovery of reproductive traits, which is relatively fast as regenerating forest scores are generally similar or higher to those in old-growth forests. Generally, regenerating forest stands support more specialized reproductive traits and strategies than old-growth forest stands [e.g., edible fruit plants with very large flowers (>30 mm), specialized pollination systems, large fruits (>1.5 ≤3.0 mm), and medium-sized seeds (>0.6 ≤1.5 cm). However, the functional diversity of specialist reproductive traits decreased with increases in the levels of biomass and aridity, isolated, but was also impacted by the interactive effect. Considering the effects of biomass, CAD or aridity individually, we observed that biomass itself was responsible for most of the effects (42.8%), while 52.3% of the reproductive traits were negatively affected by CAD or aridity, which seems to be a major force against the recovery. [Display omitted] • Secondary forests harbor similar abundance of edible fruit plants as mature forests. • Aridity reduces the species richness of edible fruit plant assemblages. • Secondary forests harbor more specialized traits and strategies than mature forests. • The successional trajectory goes from specialized to generalist traits. • Aridity act as a strong environmental filter against regeneration. [ABSTRACT FROM AUTHOR]

The mammalian Y chromosome gene families in the ampliconic region are expressed predominantly or exclusively in the testis, and their copy number variations (CNV) are significantly associated with male reproductive traits, suggesting they have important roles in spermatogenesis and testicular development. ZNF280AY (zinc finger protein 280A, Y-linked) is a member of the zinc finger protein family and has been identified as a bovid-specific Y-chromosome gene. The current study applied a reliable quantitative real-time PCR method to estimate the CNV of ZNF280AY in 715 bulls across 21 cattle breeds and to further investigate the association of the CNV of ZNF280AY with bull reproductive traits and ZNF280AY mRNA expression levels in adult testis. The results revealed that the median copy number of ZNF280AY was 47, and the copy number varied from 11 to 154, showing significant CNV between and within the investigated cattle breeds. In addition, all 715 bulls were classified into Y1, Y2, and Y3 lineage groups based on a rapid genotyping method described previously. Pairwise comparisons indicated that bulls belonging to the Y1 lineage had a significantly lower median copy number (40) than bulls belonging to the Y2 (52) and Y3 lineages (57). Association analysis revealed that the CNV of ZNF280AY was correlated negatively with the percentage of normal sperm and sperm concentration in Holstein bulls, whereas no significant correlation was observed with ejaculation volume, total sperm count, sperm motility, postthaw motility (PTM), and scrotal circumference in Holstein and Simmental bulls. Furthermore, no correlation was observed between ZNF280AY copy number and ZNF280AY mRNA expression levels in the testis. The current study suggests that the CNV of the ZNF280AY gene family is associated with male reproductive traits and may serve as a valuable marker for early bull fertility selection in Holstein breeding programs. [ABSTRACT FROM AUTHOR]

Lysine demethylase 6A (KDM6A, also known as UTX), which belongs a type of histone demethylase, is essential for spermatogenesis and embryo development. However, in pig, the coding sequence, mRNA expression and insertion/deletion (indel) variants of KDM6A remain unclear. Herein, the open-reading frame (ORF) of pig KDM6A gene was cloned and characterized. The entire ORF sequence was 4206 bp in length encoding a deduced protein of 1401 amino acid residues. The phylogenetic tree and signatures of selection on the pig KDM6A gene were calculated, and the results revealed that the pig KDM6A gene has been under strong positively selection. Expression analysis results showed that KDM6A gene was expressed in all tissues tested both in male piglets and adult boars. Meanwhile, with testicular development, the KDM6A expression levels in testis were significantly increased. Additionally, three intronic indels of 11-bp insertion, 17-bp deletion and 16-bp insertion were identified. Association analyses revealed that the 11-bp indel was associated with testicular short perimeter (TSP) (P < 0.01), testicular long perimeter (TLP) (P < 0.01) and testicular weight (TW) (P < 0.01) in 15-day-old Yorkshire and TLP (P < 0.01) in 40-day-old Yorkshire. The 16-bp indel was associated with TLP, TSP and TW (P < 0.05) in 15-day-old Yorkshire. All these findings would provide a foundation for the further research of KDM6A gene and the application of marker-assisted selection to pig breeding. • A new open-reading frame (ORF) of pig KDM6A gene was identified. • The KDM6A gene was ubiquitously expressed and significantly increased with testicular development (P < 0.05). • Three indels were verified to associate with pig testicular morphology traits (P < 0.01). [ABSTRACT FROM AUTHOR]

A study was conducted to evaluate the effect of heat stress on the expression pattern of reproduction related genes in Malabari breed of goat. The study was conducted during 45 days using twelve 10 months to one year old Malabari goats. The goats were randomly allocated into two groups: MC (n = 6; Malabari control) and MHS (n = 6; Malabari heat stress). Goats were stall-fed with a diet composed of 60% roughage and 40% concentrate. All animals had access to ad - libitum feed and water and they were fed and watered individually. The MC goats were placed in the shaded pens while MHS goats were exposed to heat stress in outside environment between 10.00 h and 16.00 h. At the end of study period, all 12 animals were slaughtered and their uterus tissues were collected for gene expression and histopathological studies. The temperature humidity index (THI) inside shed (74.9) proved that the animals were not stressed while in the outside environment (86.5) the animals were extremely distressed. Heat stress significantly (P < 0.05) influenced the expression patterns of follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), estrogen receptor α (ESTRα), prostaglandin F2 α (PGF2α) and cyclooxygenase-2 (COX-2). However, prostaglandin E2 (PGE2) did not differed between the groups. Further, a strong positive correlation (P < 0.01) was established for THI with both FSHR gene expression. A negative correlation was also established between THI and ESTRα (P < 0.01), PGF2α (P < 0.01), PGE2 (P < 0.05) genes. However, heat stress did not influence the expression patterns of LHR ; COX-2 genes. The histopathological section of uterine epithelial cells showed degenerative changes (P < 0.05) with less differentiation in MHS group as compared to MC group. The results from the study clearly indicated that heat stress was able to alter the reproductive activity related gene expressions at uterine level and this could be an indication of reduced reproductive efficiency in Malabari goats. • Impacts of heat stress on livestock reproduction are mainly based on changes in the phenotypic rather than genotypic traits. • The study is the first of its kind to establish the impact of heat stress on reproduction related gene expression in goats. • ESTRα, PGF2α and PGE2 genes can be considered as indicators for heat stress effect on reproductive performance in goats. [ABSTRACT FROM AUTHOR]

Abstract The objective of this study was to estimate heritability as well as genetic and environmental relationships between days to first heat (DFH), days to first service (DFS), interval from calving to conception (ICC), calving interval (CI) and number of inseminations per conception (NIS) with mastitis (Mast), number of mastitis occurrence (NumMast), different measures of somatic cell count (SCC) and fat to protein ratio (F:P) in the first lactation of Holstein cows in Iran using linear and threshold animal and sire models. The 33851 first lactation records of Holstein cows from five large dairy herds with calving dates from March 2002 to September 2014 were analyzed with univariate and bivariate linear and threshold animal and sire models using Gibbs sampling methodology. Data from parity one to nine comprising 62483 records were used to conduct repeatability model analysis for reproductive traits. Heritabilities of the reproduction traits varied from 0.067 (for ICC) to 0.105 (for DFH) using linear animal models. Also, the heritabilities of udder health traits varied from 0.005 to 0.102 using different models. The repeatabilities of reproductive traits ranged from 0.110 to 0.307. In general, the genetic correlations (r g) between reproduction traits were positive and high (with the exception of r g between DFH-NIS). The r g between reproduction traits with udder health traits ranged from −0.029 to 0.359 and 0.151 to 0.584 using linear-linear and threshold-linear animal models, respectively. Generally, there was favorable r g between reproduction traits with udder health traits; therefore, selection for one set of these traits would improve the correlated traits. However, due to different (co)variance components and economic weights in each country/region, it can be recommended to investigate inclusion of both sets of these traits in breeding objectives. Highlights • Genetic parameters were estimated for some reproductive and udder health traits of Holstein cows. • Udder health traits and reproductive traits had low heritabilities using different models. • The genetic correlation between udder health traits and reproduction traits were favorable. [ABSTRACT FROM AUTHOR]

Highlights • Genetic evaluation for scrotal circumference in guzerat (a Bos indicus breed) beef cattle was performed. • Selection of these animals as yearlings can be performed because of the positive correlation between scrotal circumference measured at 365 days of age and those measured at older ages. • The major implication is the anticipation of selection without impairing reproductive performance of the own animal and its offspring. ABSTRACT The objectives were to obtain estimates of genetic parameters and the genetic trends and to evaluate the direct responses and those correlated to the selection for scrotal circumference (SC) measured at different ages through random regression models (RRM) and multi-trait models (MM). A total of 14,200 information of SC from 4065 Guzerat individuals, with age ranging from 200 to 550 days, were used in the analyses. Both RRM and MM were utilized considering contemporary groups, as the fixed effect, and age of the mother at calving, as the covariate. For RRM, the direct additive genetic and the permanent environment effect of the animals were modeled by Legendre polynomials, with an order of fit ranging from 2 to 5. The residual variances were modeled considering variance homogeneity, and heterogeneity assuming 2, 3, and 4 classes. The results obtained by the RRM fitted better when compared with those obtained by the MM. The model that considered two classes of residual variances and polynomials of third order for the additive genetic and the permanent environment effects was the one that best fitted the scrotal circumference data according to the age based on the Bayesian and the Akaike Information criteria. Scrotal circumference heritability using RRM ranged from 0.42 (200 days of age) to 0.60 (364 days of age) and presented a low reduction from 365 until 550 (0.55) days of age. Correlation estimates for SC at the distinct ages were high (ranging from 0.66 to 0.98) and presented a reduction as the age intervals increased (0.66 ± 0.05 for SC measured at 205 days of age vs. SC measured at 550 days of age). Genetic trends of scrotal circumference were positive (ranging from 0.048 [SC measured at 205 days of age] to 0.101 [SC measured at 550 days of age]) and significant (P < 0.0001). Using the RRM, an increase in selection response were obtained compared to MM. Based on the results, we conclude that genetic evaluation of scrotal circumference can be performed at 365 days of age utilizing the RRM. [ABSTRACT FROM AUTHOR]

• It was the first report about polyploid breeding of the interspecific hybrid iris × norrisii. We obtained pure C1 1 1 Seedlings originating from seeds produced by C0 mother plants are considered C1 generation. tetraploids through hand selfing for the putative mixoploid in C0 2 2 Seedlings originating from colchicine-treated seeds are considered C0 generation. generation. • With tetraploidization, flowers were larger (by 26%), fruits became longer (by 54%), and selfing seeds were a little wider (by 10%) and significantly longer (by 33%) in size. • It was demonstrated that the size of stomata, pollen grains, flowers, ovaries and selfing seeds can be used as an index to detect tetraploidy in I. × norrisii , given that the control diploid is derived from the same line as the tetraploid. • The synthetic tetraploids exhibited a 9.10% selfing fruit-setting rate with 100% plump seeds, thus can be used as cross materials. • From 4 x × 2 x interploidy hybridization, 4.11% plump seeds (none germinated) were obtained, indicating the potential for producing interploidy hybrids. Tetraploids have been widely regarded as important contributors to the development of prime cultivars in many horticultural groups of Iris. These tetraploid plants tend to display intense flower color, increased flower size, and larger growth vitality compared to their diploid progenitors. However, no polyploid has ever been found or induced in the interspecific hybrid Iris × norrisii. In order to obtain new, innovative polyploid germplasm in I. × norrisii , 64 pre-germinated seeds were soaked with 0.05% colchicine, of which 14 survived and 6 flowered in the first growing season. Eight tetraploids were identified from the self-fertilized progeny of one of the six adult plants. The synthetic tetraploid I. × norrisii showed greater viability and developed wider leaves with larger stomata and pollen grains than their diploid counterparts. With tetraploidization, flowers were larger (by 26%), fruits became longer (by 54%), and selfing seeds were a little wider (by 10%) and significantly longer (by 33%) in size. The synthetic tetraploids exhibited a 9.10% selfing fruit-setting rate with 100% plump seeds. Conversely, most seeds collected from the interploidy cross between tetraploids and diploids were empty, with only 4.11% being plump. As a rare Iris species capable of flowering in the first growing season, the induced tetraploid I. × norrisii offers great potential to produce more genetically diverse progenies in a relatively short time, and thus provides a foundation for further research into polyploidization in Iris. [ABSTRACT FROM AUTHOR]

Qinghai fine-wool sheep is a Chinese domestic sheep breed developed by complex crossing. We established a stable genetic core population of twin lambs through artificial intervention. However, few studies have been done on the genetic fecundity of breeding varieties, probably because of the long-term nature and complexity of the work. Selection signatures associated with reproductive traits were identified by whole-genome sequencing of ewes with stable litter size differences to select candidate genes related to the increase in litter size in this breed. Several genes associated with reproductive traits were found through genome annotation, such as prostaglandin E1 receptor (PTGER1), Growth hormone receptor (GHR), and fibroblast growth factor 9 (FGF9) with significant enrichment in the phosphatidylinositol-3-kinase/Akt (Pi3k-Akt) and Ras signaling pathways, and neuroactive ligand-receptor interaction, suggesting that these pathways may affect fertility regulation. Notably, one synonymous mutation (g. 33661895 T > C) specific to the high-prolificacy group was identified in the GHR gene. In summary, this study provides a new opportunity to improve sheep fertility and provides a scientific scheme for the establishment of a productive core group. • Selection signatures associated with reproductive traits were identified by ewes with stable litter size differences to select candidate genes. • PI3K-Akt, Ras signaling pathways, and neuroactive ligand-receptor interaction pathways may affect fertility regulation. • One synonymous mutation (g. 33661895 T > C) specific to the high-prolificacy group was identified in the GHR gene. [ABSTRACT FROM AUTHOR]

The number of egg-laying is an important indicator of reproduction performance in poultry breeding. To investigate the relationship between the function of Angiotensin-converting enzyme ( ACE ) and egg-laying performance of Taihang chicken, the mRNA and protein expression and single nucleotide polymorphism (SNP) of ACE were detected. Analysis of ACE bioinformatics and association analysis of polymorphisms were then performed. The polymorphisms analysis of ACE showed that three SNP loci (g.5066812A>C, g.5080076G>A, and g.5072728A>G) were detected in 800 Taihang chickens with egg-laying records. Association analysis of egg-laying found that ACE g.5066812A>C mutation was significantly associated with the egg-laying performance of Taihang chickens (P < 0.05), and the individuals with the g.5066812A>C mutation showed significantly increasing egg-laying. The mRNA expression was significantly higher in individuals with the AA genotype mutation than those with the AC and CC genotypes (P < 0.01), and the expression of ACE protein levels was consistent with the mRNA expression. Bioinformatics analysis indicated that these mutations affected the secondary and tertiary structure of ACE. This study provides new insights into ACE affecting chicken egg production and some basis for improving the egg production rate of Taihang chickens. [ABSTRACT FROM AUTHOR]

Artificial illumination is an important exogenous factor in the control of many physiological and behavioral processes in the management of layers. The objective of this study was to examine the effect of monochromatic light on reproductive traits, fertility, and quality of eggs of local mountainous laying hens of China. Five hundred fifty-two19-wk-old hens were randomly divided into 4 groups, with each group consisting of 138 birds. Feed and water were provided ad libitum. Light treatments were control white (mini-incandescent light bulbs), blue (480 nm), green (560 nm), and red (660 nm). Birds maintained under green light produced fewer eggs than other groups. The red light group had a greater egg shape index than other groups and had greater fertility and hatchability than other groups. Egg weight was affected by light wavelength, but the rate of egg production was not. The ratio between egg components can be changed by the light source without changing the egg weight. Egg quality was the best for hens exposed to the green light. [ABSTRACT FROM PUBLISHER]

• This is the first study using machine learning methods applied to genomic-enabled classification in beef cattle breeding, particularly for stayability. • Genomic-enabled classification does not depend on parametric assumptions to select better animals under a genomic approach in situations that involve traditional "non-normal" traits. • Artificial intelligence models are recommended for genomic-enabled classification of stayability in beef cattle. Stayability (STAY) is a binary trait with significant value economically. It measures both the cow's reproductive performance and longevity simultaneously. Thus, STAY is one of the most important female selection criterion in Nellore beef cattle breeding programs. The "success" for STAY is defined as the ability of a cow to stay in the herd up to 76 months of age and to have at least three calve. Despite its importance, STAY has not been investigated under a machine learning (ML) framework, which might allow to intuitively capture linear and nonlinear relationships (e.g., non-additive effects) between a response variable and other predictor variables. In this study, we compared different ML tools using a genome-enabled approach to classify daughters (non-genotyped animals but with STAY records) of genotyped sires. In total, 44,626 STAY records from daughters of 559 bulls genotyped with the 777K SNP panel were available for this study. The genotyped data were subdivided into three SNP sets based on the top-ranked effect on STAY: 1K-, 3K-, and 5K-SNP panels. The following ML algorithms were evaluated: AdaBoost (ADA), Naïve Bayes (NB), Decision Tree (DT), Deep Neural Network (DNN), k-Nearest Neighbors (NN), Multi-Layer Perceptron Neural Network (MLP), and Support Vector Machine (SVM). The analyses were performed using free Scikit-learn for the Python programming language. No relevant improvements in the learning process of the evaluated algorithms were observed when the number of SNPs in the genotype dataset was increased (i.e., 1K-, 3K-, or 5K-SNP panel). In short, NB outperformed the other algorithms considering, for example, the balanced accuracy (0.62 ± 0.01) and sensitivity (0.56 ± 0.02) metrics. In conclusion, the use of the 1K-SNP panel allowed efficient genomic classification and the NB algorithm outperformed the other methods as indicated by various classification metrics. To best of our knowledge, this is the first study using ML and genome-enabled classification of STAY in beef cattle. [ABSTRACT FROM AUTHOR]

Abstract: Bone morphological protein 7 (BMP7) has been proposed to be an osteoinductive protein. Recent data have shown that BMP7 also plays a crucial role in the growth and development, and physiological function of reproductive system. To date, studies have shown an association between the BMP gene family and reproduction in many populations, but few studies have completely described this association in sow. In the present study, three sow breeds were screened out to investigate the genetic effects of the BMP7 gene. Using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and DNA sequencing, three single nucleotide polymorphisms (SNPs) (g.35161T>C, g.35175T>C and g.35216C>T) were identified in intron 2 of the BMP7 gene. Associations between the three SNPs and the number of piglet born alive (NBA), litter weight at birth (LBW), total number of piglet born (TNB) and litter weight at 21 days were analyzed using association analysis. Among the three SNPs, g.35161T>C was significantly associated with NBA and LBW (p <0.05), and the litter weight at 21 days (p <0.01). These results suggest that g.35161T>C is a potential candidate gene locus for litter size traits and the BMP7 gene might be associated with the quantitative trait locus (QTL) controlling the litter size. These data will provide a background for more extensive characterization of the BMP7 gene. [Copyright &y& Elsevier]

Abstract: A previous cDNA microarray study showed that the prolactin (PRL) gene may be involved in the duck ovarian follicle development and egg formation process. The purpose of this study was to investigate the relationship between PRL genotypes of single nucleotide polymorphism (SNP) and reproductive traits of Tsaiya ducks. Primer pairs for the coding regions in the PRL were designed based on the duck genomic sequence database. Polymorphisms were detected by polymerase chain reaction (PCR)-single strand polymorphism (SSCP) and were verified by DNA sequencing. Six novel SNPs (T233C, T295C, G309T, C381A, G3941T and A3975C) were identified in the 1972bp region of duck PRL gene, and all of them were located in non-coding regions. Single SNP-trait association analysis showed that each SNP was associated with at least one duck reproductive trait (P <0.05). Haplotype combinations constructed on these SNPs were associated with egg weight at 40 weeks of age (EW40), fertility rate (FR) and maximum duration of fertility (MDF) (P <0.0001). In particular, diplotype H1H2 had positive effect on EW40, whereas it had negative effect on FR and MDF (P <0.05). Positive effects of the diplotype H1H5 were observed for FR and MDF, but a negative effect was observed for EW40 (P <0.05). This suggested that the PRL gene plays an important role in the regulation of egg weight and fertility-related traits and could be a potential marker in a marker assisted selection program during duck balancing selection. Further investigations on more duck populations with large sample sizes are needed to confirm this finding. [Copyright &y& Elsevier]

Abstract: Proline-rich nuclear receptor coactivator (PNRC)1 is a member of a new family of nuclear receptor coactivators capable of potentiating the transcriptional activity of nuclear receptors. The objective was to investigate the relationship between PNRC1 genotypes of single nucleotide polymorphism (SNP) and reproductive traits in ducks. Brown Tsaiya ducks (N = 305) from two lines, a control line with no selection and the selected line, were used. Polymerase chain reaction-single strand polymorphism and DNA sequencing were done to screen polymorphisms of the PNRC1 gene. A novel SNP (G98T) in 3′-untranslated region of the PNRC1 gene was identified and resulted in two genotypes, GG and GT. The frequencies of genotype GG and allele G were higher in both lines investigated. Regarding egg weight at first egg (EWFE), based on SNP trait association analysis, ducks with the GG genotype had a 4.48 g per egg greater egg weight at first egg when compared with ducks of the GT genotype in the control line (P < 0.05). In addition, this SNP was associated with the hatchability rate (HR) in the selected line; ducks with the GT genotype had a 6.70% higher hatchability rate than those with the GG genotype (P < 0.05). Therefore, we inferred that the PNRC1 gene could be a candidate locus or linked to a major gene that influenced egg weight-related and hatchability traits in Tsaiya ducks. Further investigations on additional duck populations with larger sample sizes are needed to confirm these results. [Copyright &y& Elsevier]

The objective of this study was to investigate relationships between reproductive traits in heifers and cows and yield traits for Holsteins in Japan. Insemination and lactation records for cows calved between 1990 and 2003 in Hokkaido region were obtained. Age at first service, age at conception, and conception rate for first service were calculated for heifers. Days from calving to first service, days open, and conception rate for first service were calculated for first- and second-parity cows. The yield traits used were 305-d milk, fat, and protein yields. A threshold animal model was applied for the conception rate for first service, and a linear animal model was applied for the other traits. Single-trait and 2-trait genetic analyses were performed by the Bayesian method using Gibbs sampling. Heritability estimates ranged from 0.027 to 0.051 for conception rate for first service, and from 0.074 to 0.128 for the other reproductive traits. If the relationships of other traits were not considered, days from calving to first service was favorable to genetic selection for reproductive traits because of relatively high heritability and because it can be available earlier than the days open. Genetic correlations among reproductive traits were high, especially in cows. The genetic correlations between reproductive traits for heifers and those for cows were lower than the genetic correlations between reproductive traits for first parity and those of second parity, suggesting that reproductive traits for heifers should be evaluated separately from reproductive traits for cows. Genetic correlations between yield and reproductive traits in cows were antagonistic. In contrast, genetic correlations between reproductive traits for heifers and yield traits were slightly desirable. Depending on the reporting rate of insemination records for heifers and the results of investigations for relationships with productive maturity, selection by reproductive traits for heifers will enable the improvement of reproductive performance without a loss in genetic progress for yield traits. [ABSTRACT FROM AUTHOR]

Segregation analyses performed for many livestock species indicate a mixed inheritance model of reproductive traits. Additionally, depending on the population, a given trait can be determined by a number of genes with large effects. Genetic backgrounds of hatch-ability and fertility in poultry are still not known sufficiently. The objectives of this study are to verify the hypothesis on segregation of single genes (1 vs. 2) affecting fertility and hatchability and to estimate a heritability of these traits. Records from 2,040 and 2,015 dams from full-pedigreed strains of Rhode Island Red (R33) and New Hampshire (N88) from a pedigree farm were analyzed. The percentage of fertilized eggs and the percentage of the eggs hatched of fertilized eggs were registered for dams only. Fertility was checked by candling on the eighth day of incubation. To obtain a binomial phenotypic scale, 10 eggs per dam were included into the analysis. Animal single-trait threshold models were used for the analysis of data. The first model included the effects of 2 single genes, 2 fixed effects of year and season, additive polygenic effects, and permanent environmental effects. In the second model, only 1 single gene effect was included. Additionally, the analysis based on the polygenic threshold model was also performed. The Gibbs sampling procedure was used. The significance of single gene effects was verified by highest posterior density regions. The obtained results clearly gave evidence for the segregation of 1 major gene for hatchability in strain R33. Furthermore, the mixed inheritance model can also be suggested for fertility in this strain. After the analysis, the polygenic heritabilities were very low (<0.11), whereas major polygenic heritability ranged from 0.05 to 0.12. [ABSTRACT FROM AUTHOR]

Variance components and breeding values were estimated for 3 reproductive traits in a pure line of White Leghorn laying hens. The traits were proportion of fertile eggs of eggs set, proportion of first quality chicks of eggs set, and proportion of first-quality chicks of fertile eggs. A total of 3,020 hens were tested up to 3 times over a period of 7 d. For the definition of the traits, each egg was scored for each trait either as 0 or 1. To account for the binomial distribution of the data, a Bayesian animal threshold model implemented in a Gibbs sampler was applied that considered the record of each egg set as a repeated observation of the hen. The estimated heritability was 0.067, 0.126, and 0.136 for the traits proportion of fertile eggs of eggs set, proportion of first quality chicks of eggs set, and proportion of first-quality chicks of fertile eggs, respectively, and the SE were small. It was shown that the heritability estimates were substantially higher from their expected values based on linear models. This results in a higher genetic progress and consequently favors the applied Bayesian threshold model for a genetic evaluation of binomial distributed reproductive traits. [ABSTRACT FROM AUTHOR]

Abstract: Improvement of female fertility has become of fundamental importance for profit maximization in the beef cattle herds. Consequently, animal breeding programs in Brazil have applied selection effort to traits related to reproduction as for scrotal circumference (SC), which is already incorporated to the selection routine of the breeders. However, studies have reported no favorable genetic correlation (r g) of SC with some fertility traits. Recently, stayability (STAY) has been used as means to better indicate and improve female fertility. Values for r g of STAY with reproductive and productive traits are not available in literature. Therefore, the objectives of the present study are to analyze the r g between SC and STAY and STAY with weight at 550 days (W550) in Nelore cattle. Data set of 55,682, 28,507 and 59,750 animals for STAY, SC and W550, respectively, were analyzed using two-trait animal model based on Gibbs sampling algorithm. The estimate of posterior r g between STAY and SC was 0.07±0.03, which can be considered as low and suggesting that STAY does not have sensible relation with SC. The r g of STAY and W550 was 0.15±0.01, considered low, although positive. It means that selection for W550 should not negatively affect STAY. [Copyright &y& Elsevier]

The objective of the present study was to determine the possibility of using stayability (STAY) of dams as a selection criterion for fertility in the Nelore breed. STAY was defined as whether or not a cow calved in a herd at a specific age or after this age given that she had calved at an earlier age. The specific ages studied were 5 (STAY5), 6 (STAY6) and 7 (STAY7) years. Data on 53 271, 46 011 and 41 517 animals were analyzed for the respective ages. The Method R was used to estimate the variance components and a maximum threshold a posteriori model was used to predict the genetic values. The analyses provided h2 estimates of 0.117±0.003, 0.122±0.004 and 0.171±0.005 for STAY5, STAY6 and STAY7, respectively. The ease with which the trait can be recorded and the h2 estimates indicate that the use of this trait as a selection criterion can contribute to increased dam fertility. [Copyright &y& Elsevier]