Animal Reproduction (AR)
https://animal-reproduction.org/article/doi/10.1590/1984-3143-AR2023-0073
Animal Reproduction (AR)
ORIGINAL ARTICLE

Foal sex in Thoroughbred horses: related factors

Jonas Gomes Flores; Verônica La Cruz Bueno; Henrique Boll de Araujo Bastos; Sandra Mara da Encarnação Fiala Rechsteiner

http://dx.doi.org/10.1590/1984-3143-AR2023-0073 Anim Reprod, vol.21, n3, e20230073, 2024
PDF
Downloads: 0
Views: 268

Abstract

Reproductive biotechniques in the equine species have advanced in the last decade and horse breeders have started to question the possibilities of interfering in the determination of foal sex. The aim of the present study was to verify whether the variables mares and stallion’s age, side of the ovary containing the preovulatory follicle, preovulatory follicle diameter, time between breeding and ovulation, and ovulation inducing hormones influence the sex of the foal. A total of 259 reproductive cycles of 160 mares and 22 Thoroughbred stallions were used. Statistical analysis was performed using R software, including Pearson's chi-square test and logistic regression. Of the total foals born, 136 were males (52.51%) and 123 were females (47.49%). In mares that ovulated with -24h after ovulation induction, 104 foals (54.74%) were males and 86 (45.26%) were females, while in mares that ovulated with +24h, 32 foals (46.38%) were males and 37 (53.62%) were females. Stallions up to 15 years old had 44.14% (n=49) females and those over 15 years had 49.66% (n=73) females. The simple logistic regression model showed that mares and stallions under 15 years old, mares with ovulation time less than 24 hours and treated with Deslorelin had a higher probability of having male foals, but the Pearson's chi-square test showed that foals gender were not influenced by the variables studied.

Keywords

concept, equine, influence

References

Abecia JA, Arrébola F, Palacios C. Offspring sex ratio in sheep, cattle, goats and pigs: influence of season and lunar phase at conception. Biol Rhythm Res. 2016;48(3):417-24. http://doi.org/10.1080/09291016.2016.1268325.

Aurich C, Schneider J. Sex determination in horses - current status and future perspectives. Anim Reprod Sci. 2014;146(1-2):34-41. http://doi.org/10.1016/j.anireprosci.2014.01.014. PMid:24598214.

Ben-Rafael Z, Matalon A, Blankstein J, Serr DM, Lunenfeld B, Mashiach S. Male to female ratio after gonadotropin-induced ovulation. Fertil Steril. 1986;45(1):36-40. http://doi.org/10.1016/S0015-0282(16)49093-X. PMid:3080345.

Cameron EZ, Linklater WL, Stafford KJ, Veltman CJ. Birth sex ratios relate to mare condition at conception in Kaimanawa horses. Behav Ecol. 1999;10(5):472-5. http://doi.org/10.1093/beheco/10.5.472.

Cameron EZ, Linklater WL. Extreme sex ratio variation in relation to change in condition around conception. Biol Lett. 2007;3(4):395-7. http://doi.org/10.1098/rsbl.2007.0089. PMid:17439844.

Cameron EZ. Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism. Proc Biol Sci. 2004;271(1549):1723-8. http://doi.org/10.1098/rspb.2004.2773. PMid:15306293.

Edwards AW. The genetical theory of natural selection. Genetics. 2000;154(4):1419-26. http://doi.org/10.1093/genetics/154.4.1419. PMid:10747041.

Giraldo AM, Hylan D, Bondioli KR, Godke RA. Distribution of sexes within the left and right uterine horns of cattle. Theriogenology. 2010;73(4):496-500. http://doi.org/10.1016/j.theriogenology.2009.10.006. PMid:19962748.

Gutiérrez-Adán A, Oter M, Martínez-Madrid B, Pintado B, De La Fuente J. Differential expression of two genes located on the X chromosome between male and female in vitro-produced bovine embryos at the blastocyst stage. Mol Reprod Dev. 2000;55(2):146-51. http://doi.org/10.1002/(SICI)1098-2795(200002)55:2<146::AID-MRD3>3.0.CO;2-F. PMid:10618653.

Gutiérrez-Adán A, Pérez-Garnelo, Granados J, Garde JJ, Pérez-Guzmán M, Pintado B, De La Fuente J. Relationship between sex ratio and time of insemination according to both time of ovulation and maturational state of oocyte. Zygote. 1999;7(1):37-43. http://doi.org/10.1017/S0967199499000374. PMid:10216915.

Hall S, Jarrin-Yepez P, Schneider L, Klabnik-Bradford J, Riddle W, Friend W, Schnobrich M, Prado T. Influence of period between breeding and ovulation on foal sex ratio. Clin Theriogenology. 2022;14(1):18-31. http://doi.org/10.58292/ct.v14.9294.

Harlap S. Gender of infants conceived on different days of the menstrual cycle. N Engl J Med. 1979;300(26):1445-8. http://doi.org/10.1056/NEJM197906283002601. PMid:449885.

Hosmer JR, David W, Stanley L, Rodney X. Applied logistic regression. Hoboken: John Wiley & Sons; 2000. http://doi.org/10.1002/0471722146.

Hylan D, Giraldo AM, Carter JA, Gentry GT Jr, Bondioli KR, Godke RA. Sex ratio of bovine embryos and calves originating from the left and right ovaries. Biol Reprod. 2009;81(5):933-8. http://doi.org/10.1095/biolreprod.109.077727. PMid:19587332.

James WH. Evidence that mammalian sex ratios at birth are partially controlled by parental hormone levels at the time of conception. J Theor Biol. 1996;180(4):271-86. http://doi.org/10.1006/jtbi.1996.0102. PMid:8776463.

Krackow S. The developmental asynchrony hypothesis for sex ratio manipulation. J Theor Biol. 1995;176(2):273-80. http://doi.org/10.1006/jtbi.1995.0197. PMid:7475115.

Liu Y, Zhi M, Li X. Parental age and characteristics of the offspring. Ageing Res Rev. 2011;10(1):115-23. http://doi.org/10.1016/j.arr.2010.09.004. PMid:20887815.

Martinez F, Kaabi M, Martinez-Pastor F, Alvarez M, Anel E, Boixo JC, de Paz P, Anel L. Effect of the interval between estrus onset and artificial insemination on sex ratio and fertility in cattle: a field study. Theriogenology. 2004;62(7):1264-70. http://doi.org/10.1016/j.theriogenology.2004.01.002. PMid:15325553.

Navara KJ. Hormone-mediated adjustment of sex ratio in vertebrates. Integr Comp Biol. 2013;53(6):877-87. http://doi.org/10.1093/icb/ict081. PMid:23892413.

Nicolich MJ, Huebner WW, Schnatter AR. Influence of parental and biological factors on the male birth fraction in the United States: an analysis of birth certificate data from 1964 through 1988. Fertil Steril. 2000;73(3):487-92. http://doi.org/10.1016/S0015-0282(99)00576-2. PMid:10689000.

Noorlander AM, Geraedts JP, Melissen JB. Female gender pre-selection by maternal diet in combination with timing of sexual intercourse--a prospective study. Reprod Biomed Online. 2010;21(6):794-802. http://doi.org/10.1016/j.rbmo.2010.08.002. PMid:21051285.

Pinto CRF. Use of prostaglandin F2 alfa for controlling the mare’s estrous cycle. In: AAEP Annual Convention; 2013; Nashville: American Association of Equine Practitioners; 2013. v. 59, p. 337-41.

Rath D, Moench-Tegeder G, Taylor U, Johnson LA. Improved quality of sex-sorted sperm: a prerequisite for wider commercial application. Theriogenology. 2009;71(1):22-9. http://doi.org/10.1016/j.theriogenology.2008.09.027. PMid:18995893.

Rezagholizadeh A, Gharagozlou F, Akbarinejad V, Youssefi R. Left-sided ovulation favors more male foals than right-sided ovulation in Thoroughbred mares. J Equine Vet Sci. 2015;35(1):31-5. http://doi.org/10.1016/j.jevs.2014.11.001.

Rorie RW, Lester TD, Lindsey BR, McNew RW. Effect of timing of artificial insemination on gender ratio in beef cattle. Theriogenology. 1999;52(6):1035-41. http://doi.org/10.1016/S0093-691X(99)00192-2. PMid:10735110.

Sakai N, Endo A. Effects of induced ovulation by pregnant mare’s serum and human chorionic gonadotropin on the sex ratio of mouse fetuses. Gamete Res. 1987;16(4):319-22. http://doi.org/10.1002/mrd.1120160406. PMid:3506919.

Saltz D, Rubenste D. Population dynamics of a reintroduced asiatic wild ass (equus hemionus) herd. Ecol Appl. 1995;5(2):327-35. http://doi.org/10.2307/1942025.

Samper JC, Morris L, Peña FJ, Plough TA. Commercial breeding with sexed stallion semen: reality or Fiction? J Equine Vet Sci. 2012;32(8):471-4. http://doi.org/10.1016/j.jevs.2012.06.018.

Santos MM, Maia LL, Nobre DM, Oliveira JF No, Garcia TR, Lage MC, de Melo MI, Viana WS, Palhares MS, da Silva JM Fo, Santos RL, Valle GR. Sex ratio of equine offspring is affected by the ages of the mare and stallion. Theriogenology. 2015;84(7):1238-45. http://doi.org/10.1016/j.theriogenology.2015.07.001. PMid:26234461.

Sartorelli EM, Mazzucatto LF, de Pina-Neto JM. Effect of paternal age on human sperm chromosomes. Fertil Steril. 2001;76(6):1119-23. http://doi.org/10.1016/S0015-0282(01)02894-1. PMid:11730737.

Scoggin CF. Not just a number: effect of age on fertility, pregnancy and offspring vigour in thoroughbred brood-mares. Reprod Fertil Dev. 2015;27(6):872-9. http://doi.org/10.1071/RD14390. PMid:25786411.

Silk JB. Local resource competition and facultative adjustment of sex ratios in relation to competitive abilities. Am Nat. 1983;121(1):56-66. http://doi.org/10.1086/284039.

Smith JM. A new theory of sexual investment. Behav Ecol Sociobiol. 1980;7(3):247-51. http://doi.org/10.1007/BF00299371.

Stone BA, Alex A, Werlin LB, Marrs RP. Age thresholds for changes in semen parameters in men. Fertil Steril. 2013;100(4):952-8. http://doi.org/10.1016/j.fertnstert.2013.05.046 PMid:23809502.

Trivers RL, Willard DE. Natural selection of parental ability to vary the sex ratio of offspring. Science. 1973;179(4068):90-2. http://doi.org/10.1126/science.179.4068.90. PMid:4682135.

Wilcox AJ, Weinberg CR, Baird DD. Timing of sexual intercourse in relation to ovulation: effects on the probability of conception, survival of the pregnancy, and sex of the baby. N Engl J Med. 1995;333(23):1517-21. http://doi.org/10.1056/NEJM199512073332301 PMid:7477165.

Zarutskie PW, Muller CH, Magone M, Soules MR. The clinical relevance of sex selection techniques. Fertil Steril. 1989;52(6):891-905. http://doi.org/10.1016/S0015-0282(16)53148-3. PMid:2687028.
 

Submitted date:
06/02/2023

Accepted date:
06/03/2024

66ad1392a953951c6f6ce964 animreprod Articles
Links & Downloads
1984-3143 (Electronic) 1806-9614 (Printed)
Anim Reprod ©2024 All rights reserved.

Anim Reprod

Share this page
Page Sections