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PubMed1991

Morbidity of systemic lupus erythematosus: role of race and socioeconomic status.

OBJECTIVE: To determine if differences in morbidity of systemic lupus erythematosus (SLE) as measured by (1) important renal disease, (2) number of hospitalizations, and (3) neurologic disease can be explained by race, socioeconomic status (SES), or measures of compliance. DESIGN: The interrelationship of black race, SES, and the physician's assessment of compliance as risk factors for morbidity was examined in a cohort of 198 patients with SLE (179 female, 115 black). SES was measured with Nam-Powers scores for education (years), income, and job status, and source of insurance; compliance was assessed by physician global assessment and percent of protocol visits kept. Morbidity outcomes were important renal disease (creatinine level 1.5 mg/dL or greater, renal failure, nephrotic syndrome), neurologic involvement, and number of hospitalizations. SETTING: The Johns Hopkins Rheumatology Faculty Practice, in which both private and clinic patients are seen. RESULTS: Black patients had significantly lower SES on all measures (p less than 0.0001) and were also less compliant by physician global assessment (odds ratio [OR] = 0.39, p = 0.002). Univariate analyses showed that blacks had a higher frequency of important renal disease (OR = 2.07, 95% confidence interval [CI] 1.05 to 4.11) and hypertension (OR = 1.80, 95% CI 1.01 to 3.23). Important renal disease was associated with the physician global assessment of compliance (p = 0.009) and hypertension (p less than 0.001). Multiple regression models for important renal disease, including race, physician global assessment of compliance, hypertension, SES, age, and gender, identified significant associations with only physician global assessment of compliance (OR = 0.40, 95% CI 0.17 to 0.91) and hypertension (OR = 5.37, 95% CI 2.40 to 11.98); black race was not significant (OR = 1.60, 95% CI 0.68 to 3.76). The second morbidity measure, number of hospitalizations, was associated with renal disease, neurologic disease, mouth ulcers, duration of disease, and public insurance but not with black race, in the best log-linear model. Neither race, SES variables, nor physician assessment of compliance was significantly associated with neurologic disease, the third morbidity measure. CONCLUSIONS: These data fail to support an independent association of black race with morbidity in SLE; rather, they suggest that noncompliance (as measured by physician global assessment) and type of medical insurance are important factors in morbidity. Classical epidemiologic measures of SES (education, income, occupation) do not appear to be significant confounders of the relationship of race to morbidity in SLE.

Adult↗

PubMed1995

Race: a Drosophila homologue of the angiotensin converting enzyme.

We report the isolation and characterization of a putative angiotensin converting enzyme (ACE) in Drosophila, called Race. General interest in mammalian ACE stems from its association with high blood pressure; ACE has also been implicated in a variety of other physiological processes including the processing of neuropeptides and gut peristalsis. Mammalian ACE is a membrane associated zinc binding protease that converts angiotensin I (A I) into angiotensin II (A II). A II functions as a potent vasoconstrictor by triggering a G-coupled receptor system in the smooth muscles that line blood vessels. Drosophila Race is composed of 615 amino acid residues, and shares extensive sequence identity with mammalian ACE over its entire length (over 42% overall identity and greater than 60% similarity). Evidence is presented that Race might correspond to a target of the homeobox regulatory gene, zerknullt (zen). Soon after zen expression is restricted to the dorsal-most regions of the embryonic ectoderm, Race is activated in a coincident pattern and becomes associated with the amnioserosa during germ band elongation, shortening and heart morphogenesis. After germ band elongation, Race is also expressed in both the anterior and posterior midgut, where it persists throughout embryogenesis. Race expression is lost from the dorsal ectoderm in either zen- or dpp- mutants, although gut expression is unaffected. P-transformation assays and genetic complementation tests suggest that Race corresponds to a previously characterized lethal complementation group, 1(2)34Eb. Mutants die during larval/pupal development, and transheterozygotes for two different lethal alleles exhibit male sterility. We propose that Race might play a role in the contractions of the heart, gut, or testes and also suggest that Hox genes might be important for coordinating both developmental and physiological processes.

Amino Acid Sequence↗

PubMed2005

Muscle damage is linked to cytokine changes following a 160-km race.

Muscle damage and perceived soreness following the 160-km Western States Endurance Run were related to changes in plasma cytokines and use of nonsteroidal anti-inflammatory drugs (NSAIDS). Subjects included 60 ultramarathoners (mean+/-SE, age 45.3 +/- 1.1 years) who finished the race in under 30 h (26.3 +/- 0.4 h). Blood samples were collected the morning prior to and immediately following the race, and subjects recorded muscle soreness during the week following the race using a 10-point Likert scale (DOMS). Seven plasma cytokines were measured including IL-6, IL-10, IL-8, IL-1ra, granulocyte colony-stimulating factor (G-CSF), monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 1beta (MIP-1beta). Cytokine changes were compared between NSAID users and nonusers, and correlated with creatine phosphokinase (CPK) and DOMS. Significant increases were measured for all seven cytokines, with the greatest fold increases seen for IL-6 (125x), IL-10 (24x), and G-CSF (12x). CPK was correlated with changes in IL-6, G-CSF, IL-10, IL-1ra, and MCP-1 (r = .49-.68), (P < .001), but not IL-8 or MIP-1beta. DOMS averaged 7.1 +/- 0.3 the day after the race, and 5.0 +/- 0.3, 2.5 +/- 0.2, and 1.6 +/- 0.1 3 days, 5 days, and 7 days post-race, respectively, and each was correlated with CPK (r = .40-.63, P < .001) and changes in IL-6, G-CSF, IL-10, and MCP-1 (r = .28-.77, P < .05). A comparison of NSAID users (72% of athletes) and nonusers showed no differences in CPK or DOMS, but did reveal greater increases in five of seven cytokines in the NSAID users (P < .05). In conclusion, muscle damage in athletes competing in a 160-km race was significantly correlated with post-race DOMS and increases in five of seven cytokines. NSAID users did not experience a reduction in muscle damage or DOMS, but did have higher post-race plasma levels in five of seven cytokines.

Adult↗

PubMed2005

Assessing the role of race in quantitative measures of skin pigmentation and clinical assessments of photosensitivity.

BACKGROUND: Given the increasing demographic diversity in the United States, clarifying relationships between race, color, ethnicity, and disease processes is critical. OBJECTIVES: We sought to examine the correlation between objective measures of skin pigmentation, racial identification, and physician-diagnosed and self-reported skin phototypes. METHODS: A total of 558 participants (76 nonwhite) were evaluated. A subset underwent spectrometric readings and digital photography of the upper aspect of the inner arm. Self-identified race was compared with 7 measures of pigmentation. RESULTS: Race correlates best with physician-diagnosed skin phototype (r = 0.55, P < .01), whereas self-reported skin phototype, spectrometry, and colorimetry correlate poorly with race (r = 0.28, < 0.40, and r > -0.31, respectively, P < .01). Associations between race and subjective measures strengthen among patients with darker skin. CONCLUSION: Objective measures of pigmentation fail to correlate well with race, whereas race correlates moderately with physician-diagnosed skin phototype. Including objective methods of analyzing skin color may reduce subjective influences of race in assessing photosensitivity and potential risk for skin cancer.

Adult↗

PubMed2003

Activation of natural killer cell function in recreational athletes with paraplegia during a wheelchair half-marathon race.

OBJECTIVE: To investigate a part of the immune homeostasis in recreational athletes with spinal cord injury (SCI) during and after a wheelchair half-marathon race. DESIGN: Case-control study in an actual race. SETTING: The half-marathon division of an international wheelchair marathon race in Japan. PARTICIPANTS: Seven male wheelchair racers with SCI between T7 and L1. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Changes in the number and function of natural killer (NK) cells and the endocrine effects, including plasma catecholamines and cortisol in blood samples obtained the day before the race, immediately after it, and 1 day after the race. RESULTS: Both the percentage and absolute number of peripheral NK cells did not change significantly throughout the experiment. Mean NK cell cytotoxic activity +/- standard deviation increased significantly, from 45.5%+/-7.5% to 56.1%+/-5.1% (P<.01) immediately after the race and remained increased until the next day. Plasma adrenaline levels were increased (P<.05) immediately after the race and recovered 1 day later; the plasma concentration of cortisol did not change throughout the experiment. CONCLUSIONS: The wheelchair half-marathon race induced activation of NK cell function in recreational athletes with SCI between T7 and L1.

Adult↗

PubMed1993

A race-controlled human leukocyte antigen frequency analysis in lupus nephritis. The South-Eastern Organ Procurement Foundation.

Systemic lupus erythematosus (SLE) has higher incidence and mortality rates in addition to a greater risk for nephropathy in African Americans (blacks), compared with whites. We analyzed the South-Eastern Organ Procurement Foundation (SEOPF) database from 1982 through 1986 to determine if variation in human leukocyte antigen (HLA) frequencies, beyond those normally present between the races, were associated with lupus nephritis (LN). HLA antigen frequencies in 271 black and 230 white renal transplant recipients with LN as the cause of end-stage renal disease (ESRD) were compared with 4,506 race-matched cadaveric kidney donor controls. Odds ratios (ORs) and chi-square values were computed to assess the prevalence of each HLA phenotype among the cases versus the controls separately for blacks and whites. HLA-B8 and -DR2 frequencies were increased, and HLA-DR4 frequency was decreased in cases of both races compared with race-matched controls (race-combined ORs, 1.68, 1.46, and 0.49, respectively; all P < 0.01). Race-specific analyses showed that HLA-DR6 was decreased in black cases versus black controls (OR, 0.48; P < 0.001) and HLA-DR3 was increased in white cases versus white controls (OR, 1.88; P < 0.001). HLA-B8 and DR2 are positively associated and HLA-DR4 is negatively associated with LN in patients of both races. HLA-DR3 and -DR6 demonstrate race-specificity in LN and place whites at a disadvantage relative to blacks. It is likely that non-HLA-mediated genetic factors and/or environmental factors contribute to the increased risk of nephritis observed in black patients with SLE.(ABSTRACT TRUNCATED AT 250 WORDS)

Chi-Square Distribution↗

PubMed2001

Vitamin E and exertional rhabdomyolysis during endurance sled dog racing.

Exertional rhabdomyolysis (ER) is common in sled dogs, animals with high energy expenditures that consume high fat (60% of ingested calories) diets. Associations between pre-race plasma [vitamin E] and total antioxidant status (TAS) and risk of developing ER were examined in dogs competing in the 1998 Iditarod race. Pre-race blood samples were collected from 750 dogs and a second sample was collected from 158 dogs withdrawn from the race at various times. Plasma creatine kinase activity was used to identify withdrawn dogs with ER. There was no association between pre-race plasma [vitamin E] and risk of development of ER. Dogs that developed ER started the race with higher TAS, but when withdrawn, had lower TAS than unaffected dogs and had similar pre-race [vitamin E] but higher [vitamin E] at time of withdrawal. Hence, the risk of ER in sled dogs is not affected by plasma [vitamin E] before the race.

Animals↗

PubMed2003

Mortality amongst participants in Vasaloppet: a classical long-distance ski race in Sweden.

OBJECTIVE: The aim of this study was to assess mortality amongst participants in long-distance ski races during the Vasaloppet week. We considered the 90 km races for men and 90 or 30 km for women. The vast majority of the participants in these races are not competing on the elite level. It is assumed, however, that they have to undergo regular physical training during a long period of time in order to successfully finish the race. DESIGN: The cohort study consisted of 49 219 men and 24 403 women, who participated in any of the races during 1989-1998. All subjects were followed up in the National-Cause-of-Death-Register until 31 December 1999. We computed the standardized mortality ratios (SMRs) adjusting for age and calendar year. RESULTS: Overall, 410 deaths occurred, compared with 850.6 expected, yielding an SMR of 0.48 [95% confidence interval (CI) 0.44-0.53]. Low SMRs were found in all age groups in both men and women and in all groups after categorization by finishing time and number of races. The lowest SMRs were found amongst older participants and in those who participated in several races. A decreased mortality was observed in all major diagnostic groups, namely cancers (SMR = 0.61; 95% CI 0.52-0.71), diseases of the circulatory system (SMR = 0.43; 95% CI 0.35-0.51), and injuries and poisoning (SMR = 0.73; 95% CI 0.60-0.89). For lung cancer the SMR was 0.22, but even after exclusion of lung cancer the all-cancer mortality was low (SMR = 0.72; 95% CI 0.59-0.86). CONCLUSIONS: We conclude that participants in long-distance skiing races, which demand prolonged regular physical training, have low mortality. The extent to which this is due to physical activity, related lifestyle factors, genetics or selection bias is yet to be assessed.

Adolescent↗

PubMed1988

Indicators of cell breakdown in plasma of men during and after a marathon race.

Plasma indicators of muscle cell leakage and of hemolysis were studied in 23 runners before and after a marathon race. Blood samples were drawn from an antecubital vein the morning before the race (baseline), at 3 p.m., i.e., 2 h before the start, on arrival, 12 and 36 h, and 7 days later. Compared with the baseline values, the plasma creatinine phosphokinase MM and MB subfractions, aldolase and glutamicoxaloacetic transaminase activity were increased immediately after the race, rose further 12 h after the marathon, and remained elevated the race, rose further 12 h after the marathon, and remained elevated 36 h and 7 days later. The plasma lactate dehydrogenase activity and myoglobin concentration were increased on arrival and returned to the pre-race activity 7 days after the marathon. Compared with the pre-race values, the plasma haptoglobin concentration was decreased immediately and 12 h after the marathon. Our data show that indicators of muscle cell leakage and of hemolysis in plasma, withdrawn after a marathon race, remained elevated for up to 7 days after the race.

Adult↗

PubMed1996

Relationships between exhaustive mood state and changes in stress hormones following an ultraendurance race.

To investigate how the pituitary-adrenal and sympathetic nervous hormones change in psychologically exhaustive states following an ultraendurance race, the Profile of Mood States (POMS), plasma ACTH, beta-endorphin, adrenaline, noradrenaline, and serum cortisol were measured in 29 male athletes two days before, immediately after, and one day after a triathlon. Psychological exhaustion was defined as possessing low POMS vigour and high fatigue immediately post-race. Eleven subjects met the criteria for the exhaustive group, and another ten were placed in the vigour group, which possessed high vigour regardless of fatigue score and the remaining eight subjects were excluded from analysis because they did not satisfy experimental protocol. Student's t-tests revealed no significant group differences in age, race time, pre-race POMS and hormone values. Immediately post-race, serum cortisol and plasma adrenaline did not differ between groups. However, significantly lower levels of plasma beta-endorphin (p = 0.03) and noradrenaline (p = 0.05), and relatively lower levels of plasma ACTH (P = 0.08) immediately post-race were observed in the exhaustive group when compared with the vigour group. We conclude that pituitary and sympathetic nervous hormone reactivity is attenuated following ultraendurance race in athletes showing psychological exhaustion and this is independent of race performance.

Adrenocorticotropic Hormone↗

PubMed2002

Race and sex differences in the refusal of cardiac catheterization among elderly patients hospitalized with acute myocardial infarction.

BACKGROUND: Prior studies have reported race and sex differences in cardiac catheterization use after acute myocardial infarction (AMI). It is unclear whether race or sex differences in procedure refusal may contribute to this difference. We sought to determine whether cardiac catheterization refusal rates differ by patient race or sex. METHODS: We evaluated medical records of 74,745 Medicare beneficiaries hospitalized for AMI between January 1994 and February 1996 to ascertain refusal of cardiac catheterization during hospitalization. Patient race and sex were evaluated for their association with cardiac catheterization refusal adjusting for patient, physician, and hospital characteristics. RESULTS: The cardiac catheterization refusal rate in the overall cohort was 2.92% (95% CI 2.80%-3.04%). Race and sex differences in cardiac catheterization were observed after multivariate adjustment, with white women (odds ratio [OR] 1.28), black men (OR 1.34), and black women (OR 1.37) more likely to refuse cardiac catheterization than white men (OR 1.00). Relative differences in refusal were associated with only modest absolute differences in risk-standardized rates of cardiac catheterization refusal; rates were lowest for white men (2.55%), and higher for white women (3.21%), black men (3.36%), and black women (3.38%, P <.001 for global comparison). CONCLUSIONS: Patient race and sex were associated with cardiac catheterization refusal among elderly patients hospitalized with AMI. However, absolute race and sex differences in rates of procedure refusal were small, suggesting that race and sex differences in cardiac catheterization refusal provide only a partial explanation of observed differences in cardiac procedure use.

Black or African American↗

PubMed1998

A race-specific insertion of transposable element IS801 in Pseudomonas syringae pv. phaseolicola.

The isolation and cloning of a random amplified polymorphic DNA-polymerase chain reaction (RAPD-PCR) band specific for Pseudomonas syringae pv. phaseolicola race 1 allowed us to design a pair of primers that amplify 1.2-kb race 1-specific and 2.7-kb race 2-specific fragments, providing a rapid method for the identification of races by standard PCR methods. Restriction analysis revealed identical endonuclease sites in both fragments but the race 2 fragment contains a 1.5-kb insertion, identified as transposable element IS801 by sequence comparison. One complete and one partial open reading frame (ORF), each with a high probability of encoding a protein, have been identified in the 1.2-kb fragment common to both race 1 and race 2 sequences. As IS801 disrupts the partial ORF in the race 2 fragment, the complete sequence of this ORF has been obtained as well as its promoter region. The possibility that it may encode an avirulence gene is discussed as well as the role of transposable elements in pathogen evolution.

Base Sequence↗

PubMed1996

Kinematics of cross-country ski racing.

This study investigated the evolution of skiing velocity, cycle length, and cycle rate in elite and subelite skiers during cross-country ski races. Senior male cross-country skiers engaged respectively in a 30-km skating race (N = 34) or a 50-km classical race (N = 27) were videotaped as they skied two different sections of 30 m, a 7 degrees uphill, and a flat section. In the skating race, most skiers used the offset technique on uphill and the 2-skate on flat, while the preferred techniques during the classical race were the diagonal stride for uphill and double-poling on flat. Results demonstrated that faster skiers had longer cycle lengths than slower skiers except for the flat sections of the classical race. Cycle rate was not different between skiers of different performance levels in any circumstances or races. Decreased velocity observed during the second half of the skating race was almost entirely due to a decrease in cycle length. We conclude that slower athletes should emphasize extending cycle length during their technical training. Therefore, skiers should place an emphasis on strength and power training to increase their kick and pole pushes and enhance cycle length.

Biomechanical Phenomena↗

PubMed2004

Managing the evolution of Bacillus thuringiensis resistance in natural populations of the European corn borer, Ostrinia nubilalis: host plant, host race and pherotype of adult males at aggregation sites.

The European corn borer (ECB) consists of at least two, genetically differentiated host races: one feeding on maize, the other feeding on mugwort and hop. It is unclear to what extent individuals feeding on these, or other host plants, contribute to natural ECB populations. The mechanisms underlying the genetic differentiation between both races are not well understood; they may include sexual attraction via different pheromone blends (E or Z) and differences in the location of mating sites. We caught adult males with traps baited with the E or the Z blend at hop, maize, and 'mixed' sites. We determined their probable host race by allozyme-based genetic assignment, and the photosynthetic type of their host plant by stable carbon isotope analysis. Most individuals caught in Z traps had emerged from a C(4)-type plant and belonged to the maize race, whereas most individuals caught in E traps had emerged from C(3)-type plants and were but weakly differentiated from the hop-mugwort race, suggesting a strong, though not absolute, correspondence between host plant, host race and pherotype. We also found that although spatial segregation may contribute to genetic isolation between host races, moths of both host races may be present at a given location. Regarding the management of Bacillus thuringiensis (Bt) maize, our results indicate that, at least at the present study sites, it is unlikely that any wild or cultivated C(3)-type plant species could be a source of susceptible individuals that would mate randomly with Bt-resistant Z-C(4) moths emerging from Bt-maize fields.

Adaptation, Physiological↗

PubMed1989

Increase of chalcone synthase mRNA in pathogen-inoculated soybeans with race-specific resistance is different in leaves and roots.

Soybeans (Glycine max [L.] Merr.) respond to pathogens by producing isoflavonoid-derived phytoalexins. Chalcone synthase (CHS) is the first enzyme of the flavonoid/isoflavonoid biosynthetic pathway. We investigated changes in the steady state levels of CHS mRNA and other specific mRNAs at increasing times after inoculation in two different race-specific interactions, one between leaves and the bacterium Pseudomonas syringae pv glycinea (Psg), and one between roots and the fungus, Phytophthora megasperma f. sp. glycinea (Pmg). The amount of CHS mRNA increases significantly in soybean leaves inoculated with an avirulent race of Psg but not with a virulent race or water. In contrast, the increase in CHS mRNA is similar in roots inoculated with zoospores of either an avirulent or virulent race of Pmg. CHS mRNA increases significantly in pathogen inoculated roots but not in uninoculated controls. Hydroxyproline-rich glycoprotein (HRGP) has been observed by others to increase in wounded or pathogen-inoculated plants. We report here that HRGP mRNA levels are greater in roots inoculated with an avirulent Pmg race than with a virulent race, but inoculation with either race causes a significant increase in HRGP mRNA with respect to controls. Calmodulin or ubiquitin mRNA do not increase in either uninoculated or inoculated roots and leaves. The possibility that race-specific resistance in soybeans is expressed differently in different organs of the plant is discussed.

Journal Article↗

PubMed2006

Phylogeographic patterns of host-race evolution in Tephritis conura (Diptera: Tephritidae).

Host-race evolution is a prime candidate for sympatric speciation because host shifts must take place in the presence of both hosts. However, the geographic context in which the shift takes place may have strong allopatric or peripatric components if the primary host within a localized area is scarce or even goes extinct. Inference of the relative importance of the geographic mode of speciation may be gained from phylogeographic imprints. Here, we investigate the phylogeography of host races of the tephritid fly Tephritis conura from sympatric, parapatric and allopatric populations of Cirsium heterophyllum and Cirsium oleraceum (Asteraceae) in Europe, for addressing the age and direction, and the geographic context of host-race formation. Haplotype networks of the host races differed significantly in molecular diversity and topology. However, host-race haplotypes were nested within the same network, with a central haplotype H1 being the most common haplotype in both host races. C. heterophyllum flies were genetically more diverse and substructured than flies from C. oleraceum, suggesting that the latter is the derived race. The phylogeographic imprint indicates either that C. heterophyllum flies colonized C. oleraceum during range expansion or that heterophyllum flies went extinct in an area where oleraceum flies persisted (followed by re-immigration). These imprints are in concordance with peripatric diversification, probably in the European Alps and related to the last ice age, where the host-race diversification was largely completed before the postglacial range expansion on C. oleraceum to current areas of sympatry and parapatry with C. heterophyllum.

Animals↗

PubMed2005

Phenotypic and genetic parameter estimates for racing traits of Arabian horses in Turkey.

The racing records for Arabian horses used in the study were obtained from the Turkish Jockey Club. The traits used in the study were racing time, best racing time, rank, annual earnings, earnings per start, log annual earnings and log earnings per start. Genetic parameters were estimated by the restricted maximum likelihood (REML) procedure using the DFREML program. The effects of age, sex and origin of horse were significant for each trait. The effect of year was significant on time and earning traits, but not rank. The effect of month on time traits was also significant. Heritability estimates of the entire data set were 0.280, 0.281, 0.069, 0.139, 0.174, 0.152 and 0.171 for racing time, best racing time, rank, annual earnings, earnings per start, log annual earnings and log earnings per start respectively. Estimates of repeatability varied from 0.349 to 0.500 for racing time, from 0.430 to 0.524 for best racing time and from 0.129 to 0.171 for rank depending on the data set used in the analyses. Best racing time was the most appropriate trait for selection in this study, as this might lead to genetic improvement than other traits.

Age Factors↗

PubMed2006

The use of a random regression model to account for change in racing speed of German trotters with increasing age.

In a genetic analysis of German trotters, the performance trait racing time per km was analysed by using a random regression model on six different age classes (2-, 3-, 4-, 5- and 6-year-old and older trotters; the age class of 3-year-old trotters was additionally divided by birth months of horses into two seasons). The best-fitting random regression model for the trait racing time per km on six age classes included as fixed effects sex, race track, condition of race track (fitted as second-order polynomial on age), distance of race and each driver (fitted as first-order polynomial on age) as well as the year-season (fitted independent of age). The random additive genetic and permanent environmental effects were fitted as second-order polynomials on age. Data consisted of 138,620 performance observations from 2,373 trotters and the pedigree data contained 9,952 horses from a four-generation pedigree. Heritabilities for racing time per km increased from 0.01 to 0.18 at age classes from 2- to 4-year-old trotters, then slightly decreased for 5 year and substantially decreased for 6-year-old horses. Genetic correlations of racing time per km among the six age classes were very high (rg = 0.82-0.99). Heritability was h2 = 0.13 when using a repeatability animal model for racing time per km considering the six age classes as fixed effect. Breeding values using repeatability analysis over all and within age classes resulted in slightly different ranking of trotters than those using random regression analysis. When using random regression analysis almost no reranking of trotters over time took place. Generally, the analyses showed that using a random regression model improved the accuracy of selection of trotters over age classes.

Aging↗