Large Proportion Of Variance Research Articles

Physically Abused Children's Adjustment at the Transition to School: Child, Parent, and Family Factors.

Childhood physical abuse predicts emotional/behavioral, self-regulatory, and social problems. Yet factors from multiple ecological levels contribute to children's adjustment. The purpose of this study was to examine the degree to which the social-emotional adjustment of physically abused children in first grade would be predicted by a set of child-, parent-, and family-level predictors in kindergarten. Drawing on a short-term longitudinal study of 92 physically abused children and their primary caregivers, the current study used linear regression to examine early childhood child (i.e., gender, IQ, child perceptions of maternal acceptance), parent (i.e., parental mental health), and family relationship (i.e., sensitive parenting, hostile parenting, family conflict) factors as predictors of first grade internalizing and externalizing symptomatology, emotion dysregulation, and negative peer interactions. We used a multi-method, multi-informant approach to measuring predictors and children's adjustment. Internalizing symptomatology was significantly predicted by child IQ, parental mental health, and family conflict. Externalizing symptomatology and emotion dysregulation were predicted by child IQ. Although a large proportion of variance in measures of adjustment was accounted for by the set of predictors, few individual variables were unique predictors of child adjustment. Variability in the predictors of adjustment for physically abused children underscores the need for individualized treatment approaches.

Additive genetic effect of APOE and BDNF on hippocampus activity

Human memory is a highly heritable polygenic trait with complex inheritance patterns. To study the genetics of memory and memory-related diseases, hippocampal functioning has served as an intermediate phenotype. The importance of investigating gene–gene effects on complex phenotypes has been emphasized, but most imaging studies still focus on single polymorphisms. APOE ε4 and BDNF Met, two of the most studied gene variants for variability in memory performance and neuropsychiatric disorders, have both separately been related to poorer episodic memory and altered hippocampal functioning. Here, we investigated the combined effect of APOE and BDNF on hippocampal activation (N=151). No non-additive interaction effects were seen. Instead, the results revealed decreased activation in bilateral hippocampus and parahippocampus as a function of the number of APOE ε4 and BDNF Met alleles present (neither, one, or both). The combined effect was stronger than either of the individual effects, and both gene variables explained significant proportions of variance in BOLD signal change. Thus, there was an additive gene–gene effect of APOE and BDNF on medial temporal lobe (MTL) activation, showing that a larger proportion of variance in brain activation attributed to genetics can be explained by considering more than one gene variant. This effect might be relevant for the understanding of normal variability in memory function as well as memory-related disorders associated with APOE and BDNF.

Board 330 - Research Abstract Simulation-Based Assessment of ECMO Clinical Specialists (Submission #442)

Introduction/Background Extracorporeal Membrane Oxygenation [ECMO] is a life-saving measure with significant risks of morbidity and mortality for critically ill patients in cardiac or pulmonary failure. Clinical specialists in the management of ECMO patients provide continuous bedside monitoring and are the first line of defense in recognizing and responding to acute and potentially catastrophic events. However, since such events are infrequent and unpredictable, an ECMO specialist with many years of experience may never have encountered one. The purpose of this study was to create simulated scenarios of critical events to enhance the training of ECMO specialists. A second goal was to assess their performance in recognizing and responding to the simulated events. The hypothesis was that more experienced individuals would outperform the less experienced. The simulations provided a hands-on, real-time approach to the challenging and complex nature of bedside ECMO emergencies. Methods Eight scenarios, designed to reflect acute events an ECMO specialist would be expected to manage included hyperventilation, air entrainment, ventricular tachycardia, hypovolemia causing venous occlusion, agitation with arterial occlusion, pneumothorax, bleeding and hemodilution. The scenarios were created and piloted by perfusionists, critical care physicians and the ECMO nurse coordinator. These scenarios represent events that have occurred while a patient was on ECMO support. Twenty five ECMO clinical specialists consented to participate in this IRB-approved study. The subjects were oriented to the manikin and the study format and participated individually. They had five minutes to complete each scenario and an in-depth debriefing was held at the Conclusion of the session. The sessions were captured on an audiovisual system. Two trained raters scored for completion of key actions and assessed a global score. Results All twenty five participants completed the scenarios. Thirteen (52%) had less than one year of experience on the ECMO team. The generalizability coefficients were moderate for both the checklist (0.41) and global scores (0.43). Large proportions of variance were attributable to the Person x Task (P x T) interaction, suggesting that performance in one scenario was poorly predicted by performance in another. Relatively little variance was attributable to the rater, or associated interactions, indicating the raters were reasonably consistent in the assignment of scores. The standardized inter-rater reliability coefficient were comparable for the checklist scores (r=0.72) and the global scores (r=0.70). For the ANOVA of both the checklist and global scoring, the group (experience) by scenario interaction was not significant indicating that any performance differences between ECMO groups were reasonably consistent across scenarios. There was a main effect attributable to group by checklist (F=4.3, p<0.05) and global score (F=8.4, p<0.015) indicating that the more experienced ECMO group outperformed the less experienced group. Participants with >1 year experience (mean=77.5, SD=17.9) outperformed those with <=1 year experience (mean=73.1, SD=14.1) by checklist scoring as well as in their global score [>1 year: (mean=7.2, SD=1.5) versus <=1 year: (mean=6.6, SD=1.4)]. There was also a main effect attributable to scenario based on checklist scores (F=6.9, p<0.01), as well as the global rating (F=4.1, p<0.01) indicating that the scenarios were not of equal difficulty. Conclusion ECMO simulation scenarios were created for acute skills training and evaluation of ECMO clinical specialists. Regarding reliability, the study revealed a great deal of task specificity, which is not unexpected with a heterogeneous group of tasks to be accomplished. Construct validity was supported by the experienced specialists outperforming the less experienced. It was also supported by participant feedback following the sessions. In their evaluations, the participants felt that the simulation scenarios were realistic, represented events that could occur in practice and were appropriate for training. These preliminary data support the simulation of ECMO critical events for training and evaluation of clinical specialists.

The Effect of Medical Students and Residents on Measures of Efficiency and Timeliness in an Academic Medical Center Emergency Department

Research regarding the effect of trainees on emergency department (ED) operations has demonstrated mixed results. In this study, the authors evaluated the effect of trainees on ED length of stay (LOS), door to medical provider (DTMP) time, and door to disposition decision (DTDD) time while accounting for covariates known to influence ED efficiency and timeliness. The authors used retrospective cohort data for ED visits to Maine Medical Center's mixed adult and pediatric ED for the calendar years 2005 through 2009. Each visit was coded indicating the type of provider conducting the visit (student-attending, resident-attending, midlevel provider, or attending group). Ordinary least squares regression analyses were performed to examine the relationships between provider groups and ED LOS, DTMP time, and DTDD time. Hierarchical regression models were constructed to control for the confounding effects of triage acuity, time of year, laboratory testing, radiographic testing, and patient characteristics. The analysis of 246,142 visits found significant intergroup differences across provider groups for each outcome (P < .001). Multiple regression modeling revealed that treatment by trainees was a significant predictor of longer LOS (medical students and residents), shorter DTMP time (residents), and longer DTDD time (medical students and residents), after controlling for covariates. Laboratory and radiographic testing accounted for a much larger proportion of variation in outcomes than did trainees. The small increases in LOS and DTDD time are balanced by the decrease in DTMP time and the intangible benefits of educating trainees.

Monozygotic Twin Differences in Non-shared Environmental Factors Associated with Chronotype

Twin studies have highlighted that a large proportion of variability in chronotype is accounted for by individual-specific environmental factors (non-shared environmental influences). However, little research has aimed to identify specific non-shared environmental influences on chronotype. Although epidemiological studies have shed light on possible environmental influences on chronotype, a substantial amount of research has highlighted the importance of genetic influences on exposure toward specific environments, a process termed gene-environment correlation. It is possible that associations between the environment and chronotype are in part determined by genetics, rather than being purely environmental in origin. One way of exploring the contribution of purely non-shared environmental components on associations between chronotype and the environment is to use the monozygotic twin differences design. This design allows us to tease apart the influences of genetics and the environment to identify purely environmental components. One hundred eighty-nine monozygotic twin pairs (mean age 19.81 years, SD = 1.26, range = 18-22 years, 66.1% female) completed the Horne and Östberg Morningness-Eveningness Questionnaire as a measure of chronotype and questionnaires assessing the following candidate non-shared environmental influences: dependent and independent negative life events, educational attainment, employment status, relationship status, deviant peers, affiliation with deviant peers, general health, smoking, drug use, and alcohol use. Linear regression analyses indicated the presence of gene-environment correlation for the majority of associations between chronotype and candidate environmental influences. When controlling for genetic and shared environmental effects, within monozygotic twin-pair differences in chronotype were associated with within monozygotic twin-pair differences in dependent negative life events (β = -0.27, p < 0.001), educational attainment (β = -0.14, p < 0.05), smoking status (β = 0.22, p < 0.01), and drug use (β = -0.16, p < 0.01). These results suggest that some of the association between these variables is purely environmental in nature. The associations between the remaining environmental variables and chronotype, however, may be intertwined with underlying genetic factors. These findings add to our understanding of genetic and environmental mechanisms underlying the biological clock.

Genetic structure and diversity of Ukrainian red clover cultivars revealed by microsatellite markers

Polymorphism of microsatellite loci of Ukrainian red clover cultivars has been studied. 87 microsatellite alleles, which occurred in different combinations, were identified. The number of alleles ranged from 7 to 10. Microsatellite allele distribution showed that 15 alleles were common for all the red clover cultivars (17.2%). The red clover cultivars were represented by homozygous and heterozygous genotypes. The observed and expected heterozygosity ranged from 0.067 to 0.269 and from 0.225 to 0.807, respectively. An analysis of molecular variance revealed that the largest proportion of variation (68.5%) resided at the intrapopulation level. Differentiation of the Ukrainian cultivars was moderately expressed (FST = 0.07).

Total blood mercury and rubella antibody concentrations in US children aged 6–11 years, NHANES 2003–2004

BackgroundChildren are susceptible to mercury toxicity, and mercury has immunomodulatory effects. Lower folate and B-12, and higher homocysteine may represent susceptibility cofactors. A large proportion of variability in rubella immune response is attributable to environmental factors. ObjectiveThis study aimed to evaluate the interaction between total blood mercury (Hg) and nutritional and homocysteine status on rubella virus antibody concentrations. DesignCross-sectional data on rubella IgG antibody concentrations, Hg, homocysteine, methylmalonic acid (MMA, an indicator of B-12 deficiency), and folate were obtained from 2003–2004 NHANES for children aged 6–11years with rubella seropositivity (n=690). Linear regression was used to evaluate relationships between log-transformed rubella concentrations and Hg, stratified by sex, MMA≥, folate<, and homocysteine≥sample medians, adjusted for demographic and nutritional cofactors. ResultsHg was significantly positively associated with rubella antibody concentrations (β=0.24; 95% confidence interval (CI)=0.11, 0.38) in children with higher MMA, lower folate and higher homocysteine (n=110), yet inversely associated among all other children (β=−0.18; 95% CI=−0.34, −0.03) (n=580). Among the former, estimates (β) were positive across all Hg quartiles relative to the lowest (Q1) (Hg<0.30μg/L): Q2: β=0.23 (−.10, 0.56); Q3: β=0.35 (0.13, 0.57); Q4: β=0.53 (0.21, 0.84); Ptrend<0.01. ConclusionFindings are consistent with previously reported associations between Hg and measles antibody concentrations, and highlight the importance of considering dynamics between toxicant exposures, pathogens and host susceptibility.

Modeling and Predicting Cumulative Population of Bangladesh

The purpose of the present study is to build up some mathematical models for male and female forward cu- mulative population of Bangladesh. For this, the secondary data for population of Bangladesh have been taken from census of 2001. To check up the validity of the models, the model validation technique, cross-validity prediction power (CVPP), is employed in this paper. It is seen that male and female forward cumulative population of Bangladesh follow four parameters polynomial model. It is found that the parameters of these fitted models are highly significant with large proportion of variance explained. Moreover, these models are stable more than 99%. The stability of R 2 of these models is more than 99%. Hence, the fittings of these models are well.

Meditation and Psychological Health: Modeling Theoretically Derived Predictors, Processes, and Outcomes

Despite evidence attesting to positive psychological effects of meditation, little is known about how variance in the level of engagement with meditation actually relates to positive outcomes. This study draws on multiple traditional and contemporary theoretical frameworks to (1) uncover fundamental aspects of variability in meditation practice, (2) test the role of several primary and secondary processes believed to be responsible for positive effects, and (3) explore a range of positive and negative outcomes believed to be closely aligned with the original intended outcomes of meditation practices. Using two large (each N > 500) heterogeneous samples of meditation practitioners, this study calibrated and then cross-validated a theoretical model testing the plausibility of several causal pathways linking variation in experience with meditation to positive and negative psychological outcomes. Results showed that individual differences in meditation involve both behavioral aspects accounting for the degree of engagement, and psychological aspects incorporating the intensity or depth of this engagement. Variation in these aspects accounts for large proportions of variance in psychological health and functioning outcomes. Several factors representing attention refinement (mindfulness), changes in self-perception and outlook (transcendence), worldview (insight), and psychological development serve as plausible change mechanisms serving to transmit the effects of meditation on psychological health and functioning.

Modeling the Interrelationship of Learned Resourcefulness, Self-Management, and Affective Symptomatology

Self-regulatory skills models are important explanatory constructs for many societal applications. However, little research exists on the relative influence of different self-regulatory skills models for specific applications, with all relevant constructs considered simultaneously. This study evaluated the contributions of the self-regulatory models of learned resourcefulness and self-management to the outcome variable of affective symptomatology. Specifically, structural equation modeling was used to test whether learned resourcefulness accounts for additional variance in affective symptomatology when taking self-management into consideration. Results indicated that both learned resourcefulness and self-management accounted for a large proportion of variance in affective symptomatology, and the model in which the path between learned resourcefulness and affective symptomatology was constrained to zero provided the best fit of the data, tentatively suggesting that learned resourcefulness did not seem to add much value in terms of predicting affective symptomatology when in the presence of self-management. Implications for self-regulatory skills theory and models are discussed.

Meta‐Analysis of Susceptibility of Woody Plants to Loss of Genetic Diversity through Habitat Fragmentation

Shrubs and trees are assumed less likely to lose genetic variation in response to habitat fragmentation because they have certain life-history characteristics such as long lifespans and extensive pollen flow. To test this assumption, we conducted a meta-analysis with data on 97 woody plant species derived from 98 studies of habitat fragmentation. We measured the weighted response of four different measures of population-level genetic diversity to habitat fragmentation with Hedge's d and Spearman rank correlation. We tested whether the genetic response to habitat fragmentation was mediated by life-history traits (longevity, pollination mode, and seed dispersal vector) and study characteristics (genetic marker and plant material used). For both tests of effect size habitat fragmentation was associated with a substantial decrease in expected heterozygosity, number of alleles, and percentage of polymorphic loci, whereas the population inbreeding coefficient was not associated with these measures. The largest proportion of variation among effect sizes was explained by pollination mechanism and by the age of the tissue (progeny or adult) that was genotyped. Our primary finding was that wind-pollinated trees and shrubs appeared to be as likely to lose genetic variation as insect-pollinated species, indicating that severe habitat fragmentation may lead to pollen limitation and limited gene flow. In comparison with results of previous meta-analyses on mainly herbaceous species, we found trees and shrubs were as likely to have negative genetic responses to habitat fragmentation as herbaceous species. We also found that the genetic variation in offspring was generally less than that of adult trees, which is evidence of a genetic extinction debt and probably reflects the genetic diversity of the historical, less-fragmented landscape.

Quantifying variation and chemical correlates of bladderwrack quality - herbivore population makes a difference

1. Herbivory is an ecologically and evolutionarily strong interaction in marine littoral communities. However, among-host variation in quality for herbivores has not been documented comprehensively in these systems although it is a pre-requisite for selection through herbivory, and assuming an additive genetic component, for evolutionary responses. Host quality is composed of a multitude of plant traits and can thus be measured all-inclusively only in terms of herbivores' performance. In geographically structured interactions, herbivore populations may show differentiation of the traits related to host use ability, with consequent among-population variation in performance and its correlates with host traits. 2. We reared the herbivorous isopod Idotea baltica from three local populations on 30 distinct clones of its major host species, the brown alga Fucus vesiculosus. We further screened a wide array of metabolites, water content and toughness of the host clones and correlated those with the herbivore performance. 3. Food consumption of herbivores differed among host clones in all herbivore populations indicating that herbivory can generate phenotypic selection for algal traits through selective feeding. 4. The dependency of herbivore growth rate on host clone varied among the herbivore populations; among-clone variation was the highest in the herbivore population having the highest average growth rate. 5. Accordingly, the covariation patterns of algal traits with herbivore performance differed among herbivore populations. Proteinic amino acids enhanced and phlorotannins impaired growth rate but differently so depending on the population. The herbivore population having the highest average growth rate was also most sensitive to phlorotannins. Toughness of the thallus reduced growth rate in the population having on average the smallest body size and lowest growth rate. 6. That the variation in host quality explained a large proportion of variance in herbivore performance suggests that plant chemistry and structural characteristics may act as selective agents for herbivore traits and play a fundamental role in ecological differentiation of herbivore populations.

Genetic Variation and Population Structure of Arabidopsis lyrata ssp. lyrata (Brassicaceae) along the Eastern Seaboard of North America

Arabidopsis lyrata ssp. lyrata is widespread but edaphically restricted, which suggests that the dispersal ability and level of genetic exchange among populations might be limited. We assessed levels of genetic diversity and population differentiation within and among six A. lyrata ssp. lyrata populations from along the eastern seaboard of the United States by examining variation at nine microsatellite loci among 233 individuals. These data were also evaluated to assess any relationship between geographic and genetic distance and correlation of genetic diversity with population size. Measures of genetic diversity across all 9 microsatellite loci were high in most populations. Genetic diversity, as measured by number of alleles, was generally higher in the Maryland and New York populations, as compared with the southern most sampled populations in Virginia. Genetic differentiation among regions was highly significant and large (FST = 0.47). This was supported by several analyses, suggesting that there is little gene flow among the regions sampled. There was a strong positive correlation between geographic and genetic distance, which is indicative of the pattern of isolation-by-distance. Population size correlated with the number of alleles within populations, supporting population genetic theory that larger populations harbor greater genetic diversity. Wright's FST and genetic structure analysis also provided evidence of genetic partitioning at small (<100 m) geographic distances between two areas sampled within one locality. These results indicate that the largest proportion of variation was explained by within population differences and may have implications for the conservation of this widespread but fragmented taxon.

The Effects of an Instructional Intervention on Dual Language Development Among First-Grade Hispanic English-Learning Boys and Girls: A Two-Year Longitudinal Study

ABSTRACT In this article, we explore oral and reading development in Spanish and English for a sample of 70 first grade Hispanic English-learning boys and girls receiving a longitudinal English intervention and a comparison group of 70 boys and girls. Students were assessed at the outset of kindergarten and first grade, and the exit of first grade. Results showed that, on average, treatment students scored significantly better in dual oracy and Spanish literacy than control students. Girls demonstrated a faster rate in dual reading comprehension than did their boy counterparts. When the effects of treatment and gender were jointly examined, it is apparent that the treatment effect contributed to a larger proportion of variance compared to gender.

Gender-Specific Oxidative Stress Parameters

The aim of the present study was to examine the association of proteins that regulate iron transport/storage content and acute phase response with oxidative stress in male and female athletes. Serum ferritin, transferrin, soluble transferrin receptor, C-reactive protein, interleukin-6 and oxidative stress parameters (reactive oxygen metabolites, superoxide anion, advanced oxidation protein products, lipid hydroperoxides, superoxide-dismutase and pro-oxidant-antioxidant balance) were determined in 138 athletes (73 females and 65 males). A general linear model indicated significant gender differences between athletes in terms of reactive oxygen metabolites (307.48 ± 61.02 VS. 276.98 ± 50.08; P=0.030), superoxide-dismutase (114.60 ± 41.64 VS. 101.42 ± 38.76; P=0.001), lipid hydroperoxides (149.84 ± 38.95 VS. 101.43 ± 39.26; P<0.001), pro-oxidant-antioxidant balance (512.40 ± 148.67 VS. 413.09 ± 120.30; P=0.002), advanced oxidation protein products (1.49 ± 0.30 VS. 0.91 ± 0.25; P<0.001) and superoxide (2.61 ± 0.36 VS. 2.22 ± 0.35; P=0.001), which were all significantly higher in females. Multivariate analysis of covariance indicated gender (P<0.001), training experience (P=0.004), C-reactive protein (P=0.002), soluble transferrin receptor (P=0.004) and transferrin (P<0.001) as significant covariates. Gender accounted for the largest proportion of variability for all oxidative stress parameters (46.3%) and female athletes were more susceptible to oxidative stress. Iron transport and storage proteins (transferrin and ferritin), but also acute phase reactants, were negatively related factors for oxidative stress. In conclusion, variation in the ferritin level may contribute to the different oxidative stress level between the sexes.

The effects of psychopathology on subjective experience of side effects of antipsychotics in patients with schizophrenia

This study was conducted to delineate the relationship between self-reported side effects and psychopathology in schizophrenia patients. Patients with schizophrenia completed the Liverpool University Neuroleptic Side Effects Rating Scale for subjective side effects and were evaluated with the Positive and Negative Syndrome Scale for their psychopathology. Based on a series of multiple linear regression analyses, we derived a model accounting for the relationships among the specific domains of psychopathology and red herring (RH) items of the Liverpool University Neuroleptic Side Effects Rating Scale in predicting subjective side effects. The model with anxiety/depressive symptoms and RH serving as mediators between positive symptoms and side effects was found to show good fit. Positive symptoms caused mostly anxiety symptoms and tendency to report RH items, whereby resulting in over-generalized reporting of subjective side effects. However, a large proportion of variance of side effects was explained by RH, which was only partially explained by positive symptoms alone. Therefore, patients with severe levels of positive and anxiety/depressive symptoms may be prone to nocebo-like effects of antipsychotics. Studies that include acute stage patients presenting severe levels of these symptoms should not rely only on the subjective report of side effects but also apply objective measures.

Quality of life in depression: An important outcome measure in an outpatient cognitive–behavioural therapy group programme?

Studies have shown that psychiatric patients have significantly impaired quality of life (QOL) in comparison to community samples who are not suffering a mental illness. Despite an increase in research in the mental health field, there still remains little consensus as to the merit of using such questionnaires within a mental health population. There is a concern that QOL is redundant with affective state and symptomatology. We investigated the usefulness of the Quality of Life Enjoyment and Satisfaction Questionnaire-short form (QLESQ-SF) in a depressed outpatient sample receiving time-limited, standardized group cognitive-behavioural therapy. QLESQ-SF ratings were examined at admission and 10-week endpoint in an intention-to-treat (N = 212) and completers (N = 164) sample. QLESQ-SF ratings and symptom ratings (Beck Depression Inventory-II; Beck Anxiety Inventory) improved significantly over time. Hierarchical regression analyses revealed that, although affective state and change in symptomatology were significantly correlated with QOL and change in QOL, a large proportion of variance was unexplained. These results are inconsistent with the theory of measurement redundancy. QOL appears to be a useful measure that provides additional treatment outcome information distinct from affective state and symptomatology.

Housing Wealth, Financial Wealth and Consumption in China

AbstractThe paper investigates the relationship between changes in asset wealth and the trend movements of household consumption in urban China. Using the vector error correction cointegration model, we demonstrate that there is a unique long‐run cointegrating relationship between household consumption, disposable income, financial wealth and housing wealth in urban China. We find that housing wealth is the only factor that restores the long‐run equilibrium relationship when the cointegrated system is disturbed by an external shock. In addition, our permanent–transitory variance decomposition analysis indicates that nearly all variance in the movement of consumption is permanent, supporting the classical random walk hypothesis of consumption behavior. However, a large proportion of variance in the short‐run movements of housing wealth is found to be transitory.

Hypertriglyceridemia: phenomics and genomics

Hypertriglyceridemia is a common complex metabolic trait that is associated with increased atherosclerosis risk, presence of the metabolic syndrome and, with extreme elevation, increased risk of pancreatitis. Hierarchical cluster analysis using clinical and biochemical features of the Frederickson hyperlipoproteinemia types can generate hypotheses for molecular genetic studies. High throughput resequencing of individuals at the extremes of plasma triglyceride concentration has shown that both rare genetic variants with large effects and common genetic variants with moderate effects explain a relatively large proportion of variation. Very recent progress using high-density sets of genome-wide markers have identified additional genetic determinants of plasma triglyceride concentrations, albeit within largely normolipidemic subjects and with small effect sizes. Phenomic evaluation of patients with hypertriglyceridemia might help to clarify genotype-phenotype correlations and responses to interventions.

Genetic associations of sow longevity with age at first farrowing, number of piglets weaned, and wean to insemination interval in the Finnish Landrace swine population1

The objective of the study was to estimate genetic parameters for length of productive life (LPL), and determine its genetic correlation with age at first farrowing (AFF), number of piglets weaned at first farrowing (NW), and first wean-to-insemination interval (W2I) in the Finnish Landrace swine population. Data from the Finnish national litter recording scheme were utilized to estimate the genetics of LPL, and genetic associations between LPL, AFF, NW, and W2I. Data from the Finnish Landrace sow records were utilized from farms that farrowed more than 20 gilts annually from 2000 through 2005. The data set included information from 11,222 sows, all of which had AFF and NW information available. The sows producing the records evaluated were daughters of 1,267 sires, and there were 3,684 animals in the pedigree when all of the sires were traced back to founder animals. All data were obtained from FABA Breeding (Vantaa, Finland). Multivariate Bayesian analysis of Gaussian, right censored Gaussian, and categorical traits was utilized to estimate (co)variance parameters of LPL, AFF, NW, and W2I of the sow. From these traits, AFF and NW were treated as Gaussian, LPL as right-censored Gaussian, and W2I as categorical traits. Estimated posterior means of heritabilities were 0.22, 0.16, 0.09, and 0.08 for LPL, AFF, NW, and W2I, respectively. A relatively large proportion of variance due to farm-year interaction was observed (posterior means of f(2) ranged between 0.03 and 0.26). The LPL was moderately genetically correlated with NW and AFF (posterior means were -0.20 and 0.36, respectively), whereas no clear association was found between W2I and LPL. Favorable genetic correlations between AFF and W2I and between NW and W2I were also observed. Additionally, an unfavorable genetic correlation between AFF and NW was observed in the present data set. Because LPL is genetically associated with other economically important prolificacy traits, it should be included in a multiple trait swine breeding value estimation system.