Factors influencing gestation length in Mares in the Tiaret region, Algeria.

Overview

• This study investigates the length of pregnancy in Barb and Arabian mares in Algeria’s Tiaret region and identifies factors that influence how long mares carry their foals before giving birth.

Research Context and Importance

• Gestation length is an important aspect of managing horse breeding programs because it affects planning for foaling and the health of both mare and foal.
• Despite its importance, data on gestation duration in Barb and Arabian mares, especially under Algerian environmental and management conditions, is limited.
• This research contributes to filling that gap by providing locally relevant data and insights.

Study Objective

• The primary goal was to measure the gestation length in mares kept at the National Stud Farm of Tiaret, Algeria.
• The study also aimed to analyze how different factors might influence this gestation length, including:
• Breed (Barb vs. Arabian)
• Year of mating
• Month when mating occurred
• Mare’s age
• Parity (number of previous pregnancies)
• Reproductive status (specific health or physiological conditions of the mare)
• Stallion used for mating
• Sex of the foal

Methodology

• Data were collected on 133 mares over three years (2021–2024) at a national stud farm.
• Gestation length was recorded as the number of days from mating to foaling, with variability documented.
• A multivariable linear mixed model was used to analyze how each factor influenced gestation length, allowing the study to control for several variables simultaneously.
• The statistical model also included the stallion as a random effect to estimate its contribution to variance in gestation length.

Key Findings

• The average gestation length was approximately 332.5 days, with a considerable range from 300 to 361 days, indicating natural variation among mares.
• The analysis revealed that:
• Breed had a significant influence on gestation length, suggesting genetic or physiological differences between Barb and Arabian mares affect pregnancy duration.
• Reproductive status also significantly affected how long mares carried their foals, potentially reflecting health or condition-related factors impacting pregnancy duration.
• Other factors, including year and month of mating, mare age, parity, and foal sex, did not show a statistically significant impact on gestation length.
• The effect of the stallion was minor, explaining just about 5.1% of the variability, which means stallion genetics or influence has limited impact on gestation length in this population.

Conclusions and Implications

• This study highlights breed and reproductive status as the primary determinants of gestation length in mares under the specific conditions of the Tiaret region.
• Understanding these influences helps breeders and veterinarians improve reproductive management by anticipating the likely timing of foaling more accurately.
• Since stallion effect and other factors showed little influence, breeding management can focus more on mare-related characteristics for predicting gestation duration.
• The findings may assist in developing tailored healthcare, nutritional programs, and breeding schedules that optimize mare and foal health and breeding efficiency in Algeria and similar contexts.