Phenotypic and genetic analysis of reproductive traits in horse populations with different breeding purposes

Abstract

Reproductive traits have a major influence on the economic effectiveness of horse breeding. However, there is little information available. We evaluated the use of reproductive traits as selection criteria in official breeding programs to increase the reproductive efficiency of breeding studs, analysing 696 690 records from the pedigree data of eight Spanish horse populations, with different breeding purposes. The reproductive parameters studied in both sexes were age at first foaling (AFF), age at last foaling, average reproductive life and generational interval. In the females, the average interval between foaling (AIF) and interval between first and second foaling were also studied. There were clear differences between sexes and breeds, which may be due to management practices, breeding purposes and the status of the populations, rather than to differences in actual physiological conditions. Riding mares were the most precocious (AFF, 1937.64 to 2255.69 days) and had a more intensive reproductive use (AIF, 625.83 to 760.07 days), whereas sires used for meat production were the most precocious males (AFF, 1789.93 to 1999.75 days), although they had a shorter reproductive life (1564.34 to 1797.32 days). Heritabilities (0.02 to 0.42 in females and 0.04 to 0.28 in males) evidenced the genetic component of the reproductive traits, with Sport Horses having the higher average values. These results support the selection by AFF to improve reproductive aspects because of its medium–high heritability and its positive correlations with other important reproductive traits. The inclusion of the AIF is also recommended in sport populations, because this determines the length of the breaks between foaling and conditions the reproductive performance of the dams, as well as their selective intensity, genetic gain and genetic improvement. It is therefore an important economic parameter in breeding studs.

Genetic Structure Analysis of the Pura Raza Español Horse Population through Partial Inbreeding Coefficient Estimation

“…The mean F (7.51%) and AR (11.31%) values obtained in this work were lower than the values reported in the same breed by Valera et al [21], F = 8.48% and AR = 12.25%, Cervantes et al [22] F = 8.20% and Gomez et al [23] F = 8.20%. This is mainly because these authors did not include data from the two last decades, when over 70% of the PRE population was born and when management by breeders and the breeding program have become a key part of conservation genetics, aimed at avoiding matings with high levels of inbreeding [24].…”

Systematic Analysis of Breed, Methodological, and Geographical Impact on Equine Sperm Progressive Motility

“…Breed variations in equine PM reported here are consistent with literature reporting whereby Arabian stallions exhibit greater PM compared to warmblood and light horse breeds [ 28 , 39 , 40 ]. In mares, reports suggest reproductive genes involved in oocyte maturation, development, and function differ amongst Spanish breeds alongside certain fertility traits [ 41 , 42 ]. Evidence of breed differences in reproductive traits indicates significant differences in equine PM may be a function of genetic factors.…”

Breeding Strategies to Optimize Effective Population Size in Low Census Captive Populations: The Case of Gazella cuvieri

“…In these gazelle populations, their age varied from 4.88 (La Lajita) to 6.36 years (Almería). However, in other species, such as the horse, the generation interval could be up to 12 years [33], while species such as rabbit may have a generation interval of about one year [34]. In populations with a longer generation interval, the main objective of a conservation program would be to keep the genetic variability as much as possible to ensure the survival of the species in a reasonable period of time.…”