Brazilian Sport Horse: Pedigree Analysis of the Brasileiro de Hipismo Breed

Abstract

Brasileiro de Hipismo (BH) represents an open population that permits genetic input from breeds recognised by the World Breeding Federation for Sport Horses. The aim of this study was the genetic characterisation of the population as the first of a series aiming at the consolidating the current selection programme. The Brazilian Association of the Brazilian Sport Horse Breeders provided genealogical data from 1977 to 2011. A data bank containing 34,393 horses was analysed for population genetic parameters including: individual inbreeding (F), effective population size (Ne), effective number of founders (fe), effective number of ancestors (fa), and number of founder genome equivalents (fg). Analysis were run twice: for animals born until 1995 (PREVIOUS) and for those born in the last 15 years (15YEARS). Ne estimated via paired increase in coancestry consisted of 188.59 (±3.24) animals. fe was 466 and 222 for PREVIOUS and 15YEARS, respectively. Ancestors were represented by fa of 274 and 129. Mean F for 15YEARS was 0.6%; 1444 animals were inbred, with mean inbreeding of 3.33%. The difference found in fa and fe parameters, between PREVIOUS and 15YEARS, indicated the loss of original alleles. The increase in contribution from some founders represents the breeder's preference for a few horses, without the negative effect of high inbreeding levels. Brasileiro de Hipismo genetic variability agrees with its large based formation history, and should allow for genetic gain of heritable traits through selection.

Genetic Diversity of Lusitano Horse in Brazil Using Pedigree Information

“…When compared with the literature, the number of GE (5.7 in RP) can be considered low, but was higher than that reported in studies on Pantaneiro (0.7 GE) [15], Brazilian Sport Horse (1.7 GE) [18], Paint Horse (4.8 GE) [10], Quarter Horse (5.1) [19], and equal to Holstein (5.6 GE) [9]. However, the GE was lower than in Purebred Lusitano (9.9 GE) [2] and Old Kladruber (15.1 GE) [14].…”

“…Similar onsets of birth records have been reported in the literature for the Brazilian Campolina [17] and Mangalarga Marchador [31] horse breeds. A decline in the registration of births was observed in the 1990s for the Brazilian horse breeds Mangalarga [16], Campolina [17], Brazilian Sport Horse [18], and Mangalarga Marchador [31]. According to the last authors, the reduction in the number of registered births can be explained by the implementation of the economic plan of the Brazilian government that resulted in a cause-effect relationship due to the oscillations in the Brazilian economy.…”

“…Vicente et al [2], evaluating Lusitano horses using data collected throughout the world, obtained a GI that was similar to (TP) and the same as (RP) that of Lusitano in Brazil, indicating a possible influence of animals born in Brazil on the values of the world population. Although long, the GI is similar for all breeds in Brazil, such as Mangalarga (9.5 years) [16], Campolina (8.7 years) [17], Brazilian Sport Horse (10.8) [18], and Quarter Horse (9.6 years) [19]. The GI obtained in Europe for Andalusian (10.1 years) [8], Holstein (10.3 years) [9], and Old Kladruber (11.3 years) [14] was the same as those estimated for the Lusitano horse (Supplementary materialeTable A).…”

“…The complete or partial results of genetic diversity and population parameters are reported in the literature for various horse breeds, including Andalusian [8], Holstein [9], Paint Horse [10], Hanoverian [11], Spanish Arab Horse [12], Lipizzaner [13], and Old Kladruber [14]. In Brazil, studies were conducted on the Pantaneiro [15], Mangalarga [16], Campolina [17], Brazilian Sport Horse [18], and Quarter Horse [19] breeds.…”

Assessment of pedigree information in the Quarter Horse: Population, breeding and genetic diversity

“…In the present study, in addition to the database of ABQM, the ancestors of Brazilian QH animals registered until the mid-18th century were used, permitting to evaluate the present genetic diversity of the QH breed in Brazil. Cervantes et al (2008), Medeiros et al (2014) and Duru (2017) reported pedigree completeness in the first, second and third generations of 92.0%, 86.6% and 80.8% (Spanish Arab Horse in total population), 99.99%, 98.0% and 69.9% (Brazilian Sport Horse in reference population) and 98.2%, 96.6% and 95.0% (Turkish Arab Horse in reference population), respectively. Bartolomé et al (2011), Roos et al (2015) and Bhatnagar et al (2011) described combined average pedigree completeness of the five most recent generations of 71.2% (Spanish Sport Horse in total population), 88.0% (Holstein in reference population) and approximately 70.0% (Norwegian Fjord Horse in North America), respectively.…”