Quantitative study for race times in thoroughbreds on dirt and turf tracks in Brazil

This study was conducted to estimate the genetic parameters for race times on turf and dirt tracks of Thoroughbred race horses. Data used were recorded by the Turftotal Ltd. for 343,419 racing performance of 26,713 animals, from January 1992 to January 2003. The model used in analysis included random animal and permanent environmental effects, and age, post position at start, sex and race as fixed effects. The variance and covariance components and the breeding value were estimated using the MTGSAM software. Heritability estimates were 0.29 for time on dirt track and 0.25 for time on turf track, indicating a moderate association between the animals� breeding values and their phenotypic values. Although genetic and environmental variances were smaller in turf tracks, their repeatability was equal to that of dirt (0.56), in terms of the highest estimated phenotypic variance for the latter type of track. The genetic correlation between times on different tracks was high (0.70). Considering the mean breeding value of the progeny of 465 stallions with 10 or more offspring, Spearman�s correlation was 0.80, indicating that most Thoroughbred stallions produce offspring suited to both dirt and turf racing tracks.Este estudio fue conducido para estimar los parámetros genéticos de los tiempos de carrera en pistas de tierra y césped de caballos purasangres. Los datos utilizados fueron registrados por Turftotal Ltd. para 343.419 desempeños en carreras de 26.713 animales, entre enero de 1992 y enero de 2003. El modelo utilizado en el análisis incluyó animales aleatorios y efectos ambientales permanentes, y la edad, puesto en la posición de partida, sexo y raza como efectos fijos. Los componentes de varianza y covarianza y el valor genético se estimaron usando el programa MTGSAM. Los estimados de heredabilidad fueron 0,29 para el tiempo en pista de tierra y 0,25 para el tiempo en pista de césped, indicando una asociación moderada entre los valores genéticos de los animales y sus valores fenotípicos. A pesar de que las varianzas genética y ambiental fueron menores en las pistas de césped, su repetibilidad fue igual a aquella de las pistas de tierra (0,56), en términos de la más alta varianza fenotípica estimada para el último tipo de pista. La correlación genética entre los tiempos en las diferentes pistas fue alta (0,70). Considerando el valor genético promedio de la progenie de 465 sementales con 10 o más hijos, la correlación de Spearman fue 0,80, indicando que la mayoría de los sementales purasangres producen descendientes adecuados para ambas pistas de carrera (tierra y césped)

Estudio cuantitativo de los tiempos en las carreras de purasangre en pistas de tierra y césped en Brasil

This study was conducted to estimate the genetic parameters for race times on turf and dirt tracks of Thoroughbred race horses. Data used were recorded by the Turftotal Ltd. for 343,419 racing performance of 26,713 animals, from January 1992 to January 2003. The model used in analysis included random animal and permanent environmental effects, and age, post position at start, sex and race as fixed effects. The variance and covariance components and the breeding value were estimated using the MTGSAM software. Heritability estimates were 0.29 for time on dirt track and 0.25 for time on turf track, indicating a moderate association between the animals' breeding values and their phenotypic values. Although genetic and environmental variances were smaller in turf tracks, their repeatability was equal to that of dirt (0.56), in terms of the highest estimated phenotypic variance for the latter type of track. The genetic correlation between times on different tracks was high (0.70). Considering the mean breeding value of the progeny of 465 stallions with 10 or more offspring, Spearman's correlation was 0.80, indicating that most Thoroughbred stallions produce offspring suited to both dirt and turf racing tracks

Genetic evaluation of performance traits in Brazilian Quarter Horse

The aim of this study was to estimate genetic parameters for racing performance traits in Quarter Horses in Brazil. The data (provided by the Sorocaba Jockey Club) came from 3 Brazilian hippodromes in 1994-2003, with 11875 observations of race time and 7775 of the speed index (Sl), distributed in 2403 and 2169 races, respectively. The variance components were estimated by the MTGSAM program, under animal models including the random additive genetic effect, random permanent environmental effect, and the fixed effects of sex, age and race. Heritabilities for race time and the SI, for the 3 distances studied (301, 365 and 402 in), varied from 0.26 to 0.41 and from 0. 14 to 0. 19, respectively, whereas repeatabilities varied from 0.36 to 0.68 (time) and from 0.27 to 0.42 (SI) and the genetic correlations from 0.90 to 0.97 (time) and from 0.67 to 0.73 (SI)

Estudio cuantitativo de los tiempos en las carreras de purasangre en pistas de tierra y césped en Brasil

This study was conducted to estimate the genetic parameters for race times on turf and dirt tracks of Thoroughbred race horses. Data used were recorded by the Turftotal Ltd. for 343,419 racing performance of 26,713 animals, from January 1992 to January 2003. The model used in analysis included random animal and permanent environmental effects, and age, post position at start, sex and race as fixed effects. The variance and covariance components and the breeding value were estimated using the MTGSAM software. Heritability estimates were 0.29 for time on dirt track and 0.25 for time on turf track, indicating a moderate association between the animals’ breeding values and their phenotypic values. Although genetic and environmental variances were smaller in turf tracks, their repeatability was equal to that of dirt (0.56), in terms of the highest estimated phenotypic variance for the latter type of track. The genetic correlation between times on different tracks was high (0.70). Considering the mean breeding value of the progeny of 465 stallions with 10 or more offspring, Spearman’s correlation was 0.80, indicating that most Thoroughbred stallions produce offspring suited to both dirt and turf racing tracks.Este estudio fue conducido para estimar los parámetros genéticos de los tiempos de carrera en pistas de tierra y césped de caballos purasangres. Los datos utilizados fueron registrados por Turftotal Ltd. para 343.419 desempeños en carreras de 26.713 animales, entre enero de 1992 y enero de 2003. El modelo utilizado en el análisis incluyó animales aleatorios y efectos ambientales permanentes, y la edad, puesto en la posición de partida, sexo y raza como efectos fijos. Los componentes de varianza y covarianza y el valor genético se estimaron usando el programa MTGSAM. Los estimados de heredabilidad fueron 0,29 para el tiempo en pista de tierra y 0,25 para el tiempo en pista de césped, indicando una asociación moderada entre los valores genéticos de los animales y sus valores fenotípicos. A pesar de que las varianzas genética y ambiental fueron menores en las pistas de césped, su repetibilidad fue igual a aquella de las pistas de tierra (0,56), en términos de la más alta varianza fenotípica estimada para el último tipo de pista. La correlación genética entre los tiempos en las diferentes pistas fue alta (0,70). Considerando el valor genético promedio de la progenie de 465 sementales con 10 o más hijos, la correlación de Spearman fue 0,80, indicando que la mayoría de los sementales purasangres producen descendientes adecuados para ambas pistas de carrera (tierra y césped)

Avaliação do crescimento em potros da raça quarto de milha

The aim of this study was to evaluate the growth of Quarter Horse foals based on withers height, thorax perimeter, hip height, thorax width, front cannon perimeter, and thorax height measures carried on from birth to 19 months of age in 289 animals (116 males and 173 females). Sex, month and year of birth, as well as regression of animal age were included in the analysis. All effects included in the model were significant for all traits studied, except month of birth for thorax width and sex for height and width of the thorax. The phenotypic correlations among traits were positive and high, ranging from 0.87 to 0.98. For all traits the use of higher orders in the analysis model, related to the linear effect, improved the setting of growth prediction.El objetivo de este estudio fue evaluar el crecimiento de potros Cuarto de Milla con base en la alzada a la cruz,, perímetro del tórax, altura de cadera, tórax ancho, perímetro del hueso frontal de la caña, y alzada del tórax tomadas desde el nacimiento hasta los 19 meses de edad en 289 animales (116 machos y 173 hembras). Sexo, mes y año de nacimiento, así como la regresión de edad los animales se incluyeron en el análisis. Todos los efectos incluidos en el modelo fueron significativos para todos los rasgos estudiados, excepto el mes de nacimiento para anchura del tórax y sexo para alzada y anchura del tórax. La correlación fenotípica entre los rasgos fueron positivas y altas, desde 0,87 a 0,98. Para todos los rasgos la utilización de órdenes superiores en el modelo de análisis, en relación al efecto lineal, mejora de la predicción del crecimiento.O objetivo deste trabalho foi avaliar o crescimento de potros da raça Quarto de Milha a partir de medidas de altura à cernelha, perímetro torácico, altura à anca, largura do tórax, perímetro de canela, e altura do tórax realizadas do nascimento aos 19 meses de idade em 289 animais (116 machos e 173 fêmeas). Efeitos de sexo, ano e mês de nascimento, além da regressão da idade do animal à mensuração foram considerados na análise. Todos os efeitos incluídos no modelo foram significativos para todas as características estudadas, exceto mês de nascimento para largura do tórax e sexo para altura e largura do tórax. As correlações fenotípicas entre os caracteres foram positivas e de alta magnitude, variando de 0,87 a 0,98. Para as todas as características consideradas, a aplicação de ordens mais elevadas no modelo de análise, em relação ao efeito linear, melhorou o ajustamento de predição do crescimento

Caracterização da variabilidade de genes relacionados à fertilidade de machos e ao temperamento em eqüinos da raça brasileira Mangalarga

The aims of the present study were to propose a PCR-RFLP genotyping method for the AJ_315378:c.110A>G and AB_264325:c. 771G>C SNPs in the equine CRISP1 and HTR1A genes, respectively, as well as to characterize these and another polymorphism, AB_098561:c.1470G>A of the SLC6A4 gene, in order to provide a basis for future studies investigating the association between DNA markers and traits of interest in this breed. For this, 151 Mangalarga horses of both sexes, representatives of the population of the Sate of São Paulo, Brazil, were used. PCR-RFLP was found to be adequate for the genotyping of the SNPs AJ_315378: c.110A>G of the CRISP1 and AB_264325:c.771G>C of the HTR1A. However, the polymorphism of the CRISP1 probably does not occur in Mangalarga horses, a fact impairing association studies of this marker with traits related to male fertility. The estimative of the population genetic parameters obtained for the polymorphisms AB_264325:c.771G>C of the HTR1A and AB_098561:c.1470G> A of the SLC6A4 in the studied sample discourage the conduct of research addressed the association between markers and traits related to temperament

Marked assisted selection for horses racing performance

Although equines have participated in the forming and development of several civilizations around the world since their domestication 6,000 years ago in comparison to other species that have zootechnical interest, few researches have been done related to animal breeding area, especially in Brazil. Some reasons for that are difficulties associated with the species as well as operational aspects. However, developments in genetics in the last decades contributed to a better understanding of the traits related to reproduction, heath, behavior and performance of domestic animals, including equines. Recent technologies as next generation sequencing methods and the high density chips of SNPs for genotyping allowed some advances in the researches already done. These researches used basically the candidate gene strategy, and identified genomic regions related to diseases and syndromes and, more recently, the performance in sport competition and specific abilities. Using these genomic analysis tools, some regions related to race performance have been identified and based on this information; genetic tests to select superior animals for racing performance have started to be available in the market.</p

Morphological and Genomic Differences Between Cutting and Racing Lines of Quarter Horses

To investigate morphological and genomic differences between cutting and racing lines of Quarter Horses, 120 racing and 68 cutting animals of both sexes, registered at the Brazilian Association of Quarter Horse Breeders, were used. Blood samples were collected, and the following physical traits were measured: weight; height at withers; body length; length of the shank, pastern, rump, head, and neck; and chest, shank, and hoof circumference. For analysis of genomic differences, 54,602 single-nucleotide polymorphisms (SNPs) were genotyped using the Equine SNP50 BeadChip, and the quality of individual and SNP genotype data were evaluated. The fixation index, FST, was used to identify genome regions that were altered in the lines by selection. The results showed significant differences between the lines in all physical traits. Quality control led to the exclusion of four cutting animals with a call rate of <0.95. After filtering, 12,544, 13,815, and 13,370 SNPs were excluded for the whole population (n = 184), the 120 racing animals, and the 64 cutting animals, respectively. The number of informative polymorphisms detected in each line and in the whole population indicated that the Equine SNP50 BeadChip can be used in genetic studies of Quarter Horses. The fixation index, FST, identified 2,558 genome regions that may have been modified by divergent selection. © 2013 Elsevier Inc