Factors affecting gestational length in the Mangalarga Paulista breed

J R M Ferreira,M Nichi,M A Alonso,C F Guimarães,M G Meirelles,C B Fernandes

doi:10.21451/1984-3143-ar731

Abstract

The Mangalarga Paulista is a Brazilian horse breed that originated from a cross between Andalusian and Alter Real horses, and despite its national importance, no data exist regarding their gestational length. This study was conducted to determine the variation in gestation length and the influence of factors such as the sex of the foal, maternal age and parity, stallion and mating period. Retrospectively, data from 208 gestations of Mangalarga Paulista foals located in Piracaia, SP, Brazil, during the period from 1991 to 2012 were analyzed. The mean gestational length was 343.08 ± 0.66 days, with a range between 317 and 404 days. Gestation of mares carrying colts had a tendency to be longer than mares carrying fillies. Maternal parity significantly affected gestational length, with longer gestation for primiparous mares until the third gestation, shorter pregnancies between 4th and 8th gestation, and longer thereafter. Regarding mating period, mares that were mated at the end of the breeding season (January and February) had shorter pregnancies (P < 0.05). These results are of significant clinical and economic relevance for the equine industry, so that the monitoring of gestation and parturition can be performed effectively.

Highlights

Mangalarga is a Brazilian breed originated from a cross between Andalusian and Alter Real horses, both of which are from the Iberian Peninsula and they were used with the intent of producing an animal suitable for work and sport
The effect of breed on gestation length is important as a great variation can be found in the duration of pregnancy among different breeds, as reported by Allen et al (2002), who observed an effect of breed on the production of estrogens, progestogens and equine chorionic gonadotropin in Thoroughbred-in-Thoroughbred, pony-in-pony, Thoroughbred-in-pony and pony-in-Thoroughbred gestations
The gestation length observed in the present study (343.08 ± 0.66 days) was greater than reported for the breeds Lusitano and Alter Real that were the ancestors of the Mangalarga breed

Summary

Introduction

Mangalarga is a Brazilian breed originated from a cross between Andalusian and Alter Real horses, both of which are from the Iberian Peninsula and they were used with the intent of producing an animal suitable for work and sport. Other breeds were used for its final formation, including Thoroughbred, Arabian, Anglo-Arab and American Saddle Horse. According to Macpherson and Paccamonti (2011), equine gestation ranges from 320 to 362 days, contradicting a concept that only fetuses with a gestational age of 330 days would be physiologically mature. For Koterba et al (1990), gestation periods of less than 320 days or more than 365 days are considered abnormal, and these may result in the birth of immature or post-mature foals, respectively (Satué et al, 2011a)

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