Impact of inbreeding on fitness-related traits in the highly threatened Sorraia horse breed

Kjöllerström, H.J.; Gama, L. T.; Oom, María do Mar

doi:10.1016/j.livsci.2015.08.001

Cited by 11 publications

(14 citation statements)

References 22 publications

(33 reference statements)

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“…Demographic and genetic parameters, based on population structure by origin and based on founders and ancestors' contributions, have also been used to monitor the changes in a population over a short period of time (Boichard, Maignel, & Verrier, 1997). These principles have been applied to characterize the genetic diversity in several horse breeds, including both sport and isolated breeds (Bussiman et al, 2018;Duru, 2017;Giontella, Pieramati, Silvestrelli, & Sarti, 2018;Hamann & Distl, 2008;Hasler et al, 2011;Kjöllerström, Gama, & Oom, 2015;Onogi, Shirai, & Amano, 2017;Schurink, Arts, & Ducro, 2012;Vicente, Carolino, & Gama, 2012;Vostrá-Vydrová, Vostrý, Hofmanová, Krupa, & Zavadilová, 2016;Vostry, Vostra-Vydrova, Hofmanova, Vesela, & Majzlik, 2015). Those estimates can be in turn used to optimize breeding strategies to avoid loss of genetic diversity and enhance breeding programmes.…”

Section: Introductionmentioning

confidence: 99%

Exploring genetic diversity in an Italian horse native breed to develop strategies for preservation and management

Ablondi

Vasini

Beretti

et al. 2018

J Animal Breeding Genetics

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Genetic diversity is a key factor for both adaptation and response to selection. The loss of genetic diversity causes a decrease in individual fitness, and it has a dramatically negative effect on population lifespan in the long term. This study aimed at exploring the genetic diversity at pedigree level of the Bardigiano horse breed, which is a native breed from Italy shaped for living in rural areas. In 1977, the Bardigiano studbook was founded to preserve the breed and for improving its use for riding and draft purposes. Pedigree data contained 9,469 horses, of which 3,416 were alive. Demographic and genetic parameters were estimated on subpopulations to evaluate potential genetic diversity differences among breeding and nonbreeding animals, and animals showing different breeding values (EBVs) for an index combining 18 conformation traits. Throughout the studied period, inbreeding steadily increased, reaching in the last birth year cohort a mean value equal to 0.10. The rate of inbreeding per generation, assuming a mean generation interval of 8.74 years, was equal to 1.64%. Moreover, significant differences on both average relatedness and inbreeding among horses with high and low EBVs were shown. Our study unravelled the state of genetic diversity in the Bardigiano breed, highlighting that breeding strategies for optimizing the contribution of breeding animals in the coming generations are needed to ensure long-term survival of the Bardigiano horse breed.

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Section: Introductionmentioning

confidence: 99%

Exploring genetic diversity in an Italian horse native breed to develop strategies for preservation and management

Ablondi

Vasini

Beretti

et al. 2018

J Animal Breeding Genetics

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“…Some studies have similarly shown that inbreeding has no effect on gestation length [12,13], or foaling rate [11] in domestic horses. However, high levels of inbreeding in the endangered Przewalski and Sorraia horse breeds are associated with decreased birthing rates [2,3]. It is possible that inbreeding has no measurable effects on reproductive traits until it reaches a very high level.…”

Section: Discussionmentioning

confidence: 99%

“…Survival of twins is rare, so mares can only produce one foal a year. The long gestation period and short breeding season make the maintenance of good fertility rates in horse populations imperative to provide commercial returns for domestic breeds, and to increase the size of endangered populations [2,3].…”

Section: Introductionmentioning

confidence: 99%

“…The effects of inbreeding on reproductive traits vary between studies. Increased inbreeding levels were associated with reduced fertility in some domestic and wild horse populations [2,3,10]. Impaired ovarian function resulting from high levels of inbreeding was reported in the Przewalski's horse, the most closely related species to the domestic horse [3].…”

Section: Introductionmentioning

confidence: 99%

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The effects of inbreeding on covering success, gestation length and foal sex ratio in Australian thoroughbred horses

et al. 2020

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Background: Horses produce only one foal from an eleven-month gestation period, making the maintenance of high reproductive rates essential. Genetic bottlenecks and inbreeding can increase the frequency of deleterious variants, resulting in reduced reproductive levels in a population. In this study we examined the influence of inbreeding levels on foaling rate, gestation length and secondary sex ratio in Australian Thoroughbred mares. We also investigated the genetic change in these traits throughout the history of the breed. Phenotypic data were obtained from 27,262 breeding records of Thoroughbred mares provided by three Australian stud farms. Inbreeding was estimated using the pedigree of each individual dating back to the foundation of the breed in the eighteenth century. Results: While both gestation length and foaling rate were heritable, no measurable effect of inbreeding on either trait was found. However, we did find that the genetic value for both traits had decreased within recent generations. A number of environmental factors also had significant effects on foaling rate and gestation length. Secondary sex ratio had only an extremely small paternal heritable effect and was not susceptible to environmental influences. Conclusions: In contrast to racing performance, inbreeding had no measurable effect on foaling rate or gestation length in Australian Thoroughbred horses. This could be because the level of inbreeding in the population examined is not high enough to show a discernible effect on reproductive traits. Populations that experience higher levels of inbreeding due to use of artificial reproductive technologies or extremely small population sizes may show a more pronounced reduction in natural foaling rate or gestation length. It is also possible that the intensive management techniques used in the Thoroughbred population masks any negative effects of inbreeding. The decrease in the genetic value of foaling rate is likely to be because horses with unfavourable genetic potential have not yet been selected out of the population. The change in genetic value of gestation length may be due to selective breeding favouring horses with shorter pregnancies. We also found that prioritising the mating of older mares, and avoiding out of season mating could lead to an increased breeding success.

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“…Increased 50 homozygosity in highly selected animals not only causes inbreeding depression (Charlesworth & 51 Willis 2009), but also fitness problems (Leroy, 2014). While it may not be an issue in current (Kjöllerström et al 2015) or Friesian horses (Ducro et al 2006). It 61 seems necessary to monitor not only the genetic distance and genetic parameters of these 62 populations, but also their usability and differences in performance.…”

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confidence: 99%

Peer Review #1 of "Horse phenotyping based on video image analysis of jumping performance for conservation breeding (v0.1)"

2019

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Background: Many horse breeds in the world are reserved as genetic resources; however, their characteristics seem to be insufficiently clarified, especially in terms of horse performance. Two jumping ability evaluation methods have been used to compare different types of performance breeds and on this basis their applicability for precision phenotyping has been determined. Methods: Jumping data of 186 young Polish Warmblood stallions (27 with an endangered status) bred for sport and multipurpose use was collected during their performance tests organised under identical environmental conditions following the same guidelines. Jumping data consisted of objective measurements of free jumping parameters and the marks for jumping. Video recordings of 514 jumps (73 records for 27 stallions with an endangered status) were collected using a digital Panasonic AG-EZ 35 camera (25 fr/sec). Filming was recorded during a free jumping test in the line on a doublebarre obstacle (100-120 cm x 100 cm). Spatial and temporal variables of the jump were measured. The analysis of variance was performed (SAS, General Linear Model and Mixed procedures) using the statistical model, which included the random effect of the horse and fixed effects of the year of test, breeding status, height of jump and the successive number of the jump for objective kinematic data. The fixed effects of the year of test and breeding status were included in the model for subjective performance test data. Results: Performance marks for free jumping were lower in the endangered group of stallions in the trainers' opinion (p≤0.05), while no statistically significant differences were found in the judges' opinions. Statistically significant differences in jumping variables were measured for the bascule points -the elevations of the withers and croup were higher in the endangered group (p≤0.001) and the take-off time was prolonged (p≤0.05), which explained the subjective evaluation. Discussion: The use of objective evaluation methods provides important information for practice, as phenotypic differences between horses may be unclear in the subjective evaluation. The objective evaluation should be used to characterise the performance potential of different breeds, because the information from the evaluators might not be consistent. SuchPeerJ reviewing PDF | Abstract 15 Background: Many horse breeds in the world are reserved as genetic resources; however, their 16 characteristics seem to be insufficiently clarified, especially in terms of horse performance. Two 17 jumping ability evaluation methods have been used to compare different types of performance 18 breeds and on this basis their applicability for precision phenotyping has been determined. 19 Methods: Jumping data of 186 young Polish Warmblood stallions (27 with an endangered 20 status) bred for sport and multipurpose use was collected during their performance tests 21 organised under identical environmental conditions following the same guidelines. Jumping data 22 consisted of objective measurements of free ...

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Impact of inbreeding on fitness-related traits in the highly threatened Sorraia horse breed

Cited by 11 publications

References 22 publications

Exploring genetic diversity in an Italian horse native breed to develop strategies for preservation and management

Exploring genetic diversity in an Italian horse native breed to develop strategies for preservation and management

The effects of inbreeding on covering success, gestation length and foal sex ratio in Australian thoroughbred horses

Peer Review #1 of "Horse phenotyping based on video image analysis of jumping performance for conservation breeding (v0.1)"

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