Factors affecting gestation length in the Thoroughbred mare.
Abstract: In order to assist in the accurate prediction of the timing of parturition in the mare true gestation length, along with the potential effect of a number of factors, was investigated. Data from 433 Thoroughbred foal pregnancies were used. Sequential ultrasonic scanning allowed the true gestation length (fertilisation-parturition) to be ascertained, as apposed to previous work, which used the mating-parturition interval. An average gestation length of 344.1 +/- 0.49 days was evident. Colt foal pregnancies were significantly (P < 0.001) longer (346.2 +/- 0.72) than fillies (342.4 +/- 0.65). Month of birth had a significant effect on gestation length in all foals (P < 0.001). With foals born in January having the shortest gestation lengths and those born in April the longest. Mare age, year of birth, stallion age, stud farm and the interval between ovulation and mating had no significant effect. It is concluded that (i) the gestation length range (315-388 days), all resulting in viable foals is noteworthy and of clinical importance when considering the classification of dysmaturity in foals, (ii) mares carrying colt foals due to be born in the middle of the breeding season (April) are likely to have the longer gestation lengths.
Copyright 2002 Elsevier Science B.V.
Publication Date: 2002-11-06 PubMed ID: 12417119DOI: 10.1016/s0378-4320(02)00171-9Google Scholar: Lookup
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Summary
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The study aims to explore the factors that may influence the length of gestation in Thoroughbred mares. Using data from 433 pregnancies, researchers used ultrasonic scanning to accurately determine gestation length and investigated the impact of variables such as foal sex, month of birth, and mare age.
Overview of Research
- The researchers conducted a detailed study involving data from 433 Thoroughbred mare pregnancies. The main aim was to investigate how different factors impact the length of gestation.
- An accuracy method, sequential ultrasonic scanning, was used to measure the true length of gestation, from fertilisation to parturition. Prior research mainly focused on the mating-parturition interval.
- The average gestation length was determined to be around 344.1 days. However, the research highlighted a significant range, with viable foals resulting from gestation lengths of 315 to 388 days.
Findings of the Study
- The sex of the foal had a significant impact on the length of gestation. Pregnancies carrying colt foals (male) were longer, with an average length of 346.2 days, compared to fillies (female), which had a shorter gestation length of 342.4 days.
- The month of birth was found to also significantly affect gestation length. Foals born in January had the shortest gestation lengths while those delivered in April had the longest.
- Contrary to what might be expected, other variables such as the mare’s age, the year of birth, the stallion’s age, the stud farm, and the interval between ovulation and mating did not have a significant influence on the gestation length.
Conclusion and Clinical Importance
- The researchers concluded that the findings of a wide gestation length range, all resulting in viable foals, are noteworthy. Such information is particularly valuable for the classification of dysmaturity in foals.
- It has been suggested that mares carrying colt foals due to give birth in the middle of the breeding season (April) are more likely to have longer gestation lengths.
Cite This Article
APA
Davies Morel MC, Newcombe JR, Holland SJ.
(2002).
Factors affecting gestation length in the Thoroughbred mare.
Anim Reprod Sci, 74(3-4), 175-185.
https://doi.org/10.1016/s0378-4320(02)00171-9 Publication
Researcher Affiliations
- Welsh Institute of Rural Studies, University of Wales, Aberystwyth, Ceredigion, SY23 3AL, UK. mid@aber.ac.uk
MeSH Terms
- Age Factors
- Animals
- Female
- Horses / physiology
- Linear Models
- Male
- Maternal Age
- Pregnancy
- Pregnancy, Animal / physiology
- Retrospective Studies
- Seasons
- Sex Factors
Citations
This article has been cited 13 times.- Aoki T, Violin G, Jikihara T, Shibata M, Higaki S, Ozawa T, Furukawa E, Yoshioka K. Prediction of Nocturnal Foaling Using Ventral Tail Base Surface Temperature Recorded by a Wearable Device Attached to the Mare's Tail. Animals (Basel) 2026 Jan 9;16(2).
- Arafurue M, Kanno C, Sato S, Maeda Y, Takahashi F, Momozawa K, Nagano M. A retrospective study on reproduction in alpacas (Lama pacos) and cria growth after birth in Japan: the relationship between parturition and climate conditions. J Vet Med Sci 2025 Jul 7;87(7):816-820.
- Canisso IF, Amorim GBAG, Magalhaes HB. The Effect of Different Storage Temperatures over Time on the pH of Mammary Gland Secretions in Periparturient Mares. Animals (Basel) 2024 Sep 6;14(17).
- Mai Z, Fu H, Miao R, Lu C, Zhang X, Yuan Z, Ji P, Hua Y, Wang C, Ma Y, Deng H, Wei Y. Serological investigation and isolation of Salmonella abortus equi in horses in Xinjiang. BMC Vet Res 2024 Mar 15;20(1):103.
- Miller JL, Reddy A, Harman RM, Van de Walle GR. A xenotransplantation mouse model to study physiology of the mammary gland from large mammals. PLoS One 2024;19(2):e0298390.
- Aoki T, Shibata M, Violin G, Higaki S, Yoshioka K. Detection of foaling using a tail-attached device with a thermistor and tri-axial accelerometer in pregnant mares. PLoS One 2023;18(6):e0286807.
- Felici M, Sgorbini M, Baragli P, Lanatà A, Marmorini P, Camillo F. Autonomic nervous system balance in parturient mares: Spontaneous vs induced delivery. PLoS One 2023;18(3):e0283116.
- Thompson K, Taylor J, Mendez D, Chicken C, Carrick J, Durrheim DN. Willingness to adopt personal biosecurity strategies on thoroughbred breeding farms: Findings from a multi-site pilot study in Australia's Hunter Valley. Front Vet Sci 2022;9:1017452.
- Parsons Aubone AM, Bisiau CM, McCue PM, Bouma GJ. Presence of Clock genes in equine full-term placenta. J Anim Sci 2020 Apr 1;98(4).
- Smith SP, Phillips JB, Johnson ML, Abbot P, Capra JA, Rokas A. Genome-wide association analysis uncovers variants for reproductive variation across dog breeds and links to domestication. Evol Med Public Health 2019;2019(1):93-103.
- Fang L, Jiang J, Li B, Zhou Y, Freebern E, Vanraden PM, Cole JB, Liu GE, Ma L. Genetic and epigenetic architecture of paternal origin contribute to gestation length in cattle. Commun Biol 2019;2:100.
- Kuhl J, Stock KF, Wulf M, Aurich C. Maternal Lineage of Warmblood Mares Contributes to Variation of Gestation Length and Bias of Foal Sex Ratio. PLoS One 2015;10(10):e0139358.
- Phillips JB, Abbot P, Rokas A. Is preterm birth a human-specific syndrome?. Evol Med Public Health 2015 Jun 14;2015(1):136-48.
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