Reproductive parameters associated with the genetic improvement are influenced by the breed and the selection program in Spanish horses

ANTONIO MOLINA ALCALÁ; MERCEDES VALERA; MARINA SOLÉ; SEBASTIÁN DEMYDA PEYRÁS

Tours

Conferencia; 18th International Congress on Animal Reproduction; 2016

International Congress on Animal Reproduction

Reproductive efficiency in horses is usually described as low due to several limits in natural and assisted reproductive techniques. Furthermore, the incompatibility between their purpose or main activity andgestation development also contributes to an increased range of reproductive parameters, especially in mares. By that reason, reproductive parameters in horses should be evaluated and characterized considering the influence of several productive traits and situations.Despite this particular situation, some reproductive traits such as generation interval (GI, the average age of parents at the birth of their progeny kept for reproduction) or age of the stallion (AFFS) and mare (AFFM) at the first foal, have a major influence on the development and efficiency of horse breeding programs.Due to this, the objective of the present study was to evaluate the influence of the type of use and the breed of the animal in classical four-way GI (sire-son, sire-daughter, mare-son and mare-daughter), AFFS and AFFM obtained in the Spanish horse industry according to different fitness purposes: sport performance (Anglo-Arab horse ? AAH; Pura Raza Español ? PRE; Pura Raza Menorquín ? PRMe, Spanish Sport Horse ? SSH and Spanish Trotter Horse - STH), saddle (Arab horse ? AH) or meat production (Burguete - BUR). To estimatethese parameters, data from 21,203 foal births of the last 20 years in the seven horse populations were analyzed and processed with the ENDOG program (v. 4.8).GI obtained intervals ranged from 8.65 (BUR) to 13.72 (TRO) for the sire-son, 8.59 (BUR) to 13.42 (TRO) for the sire-daughter, 9.26 (PRE) to 11.52 (TRO) for the mare-son, and 9.09 (PRE) to 11.57 (TRO) for the mare daughter. The average AFFS were between 5.69 (BUR) and 10.97 (TRO), and the average AFFM were between6.27 (PRMe) and 11.01 (AAH). In general, the reproductive traits analyzed were lower for those breeds selected for meat production such as BUR, and highest for those breeds with sport performance orientation (TROT, AAH). The age at first foal was lower in comparison with the four-way GI studied for all breeds, although differences were less pronounced for BUR, denoting an increased production and lower selection intensity.Our study determined that reproductive parameters are highly influenced by the breed and the selection objective in the analyzed populations. Therefore, these parameters should be carefully used in order to characterize the reproductive efficiency and to define the reproductive management of such populations.These results also suggest that for those breeds with sport performance breeding programs (PRE, PRMe and SSH), intensity of selection is higher, affecting negatively the reproductive efficiency. The difference between the first foal and first foal kept for reproduction is higher in those sportive breeds, looking for greater reliability for the selection of future breeding horses.