Reproduction in horses encompasses the biological processes and mechanisms involved in the breeding and development of equine offspring. This includes the study of reproductive anatomy, physiology, and endocrinology in both mares and stallions. Key areas of interest include the estrous cycle, ovulation, conception, gestation, and parturition. Researchers also examine factors influencing fertility, reproductive technologies such as artificial insemination and embryo transfer, and management practices that impact reproductive success. This page compiles peer-reviewed research studies and scholarly articles that explore the physiological, genetic, and environmental aspects of equine reproduction.
The objective of this study was to enhance the in vitro sperm quality and in vivo fertility of frozen-thawed equine semen by the addition of l-carnitine (LC) to post-thawed semen. Different concentrations of LC were added to thawed samples to obtain four treatments control and 0.5, 1 and 2 mM LC. In the in vitro experiments, sperm motility and kinematics, membrane integrity and intracellular calcium ion concentration ([Ca ] ) were investigated, and the antioxidant bioactivity of LC was assessed by measuring hydrogen peroxide and nitrite concentrations (NO ). The fertility rate was assessed v...
Within the veterinary world, data regarding the surgical management of hypospadias is lacking. Reports within equines have documented resective phallectomy procedures rather than urethral reconstruction. This case report documents the first ever urethroplasty for an equine hypospadias, performed by a consultant paediatric surgeon. The urethroplasty was achieved by applying the same surgical principles mastered from paediatric urology to a horse. The indication for surgery was contact dermatitis of the hind-leg, which impaired the thoroughbred foal's racing potential. Methods: A single stage ur...
This Opinion piece is offered as a cursory overview of sperm development, function, and transport through the eyes of an equine veterinarian. My professional background is predominantly clinical in nature, but my fascination with sperm function and preservation has led to a fairly sizeable review of the scientific literature over the years in hopes of extracting laboratory findings that have application to my daily activities in the clinical arena. Spermatozoa are quite unique among cellular types with regard to both form and function, and represent the only endogenously derived cell type that...
Equine arteritis virus (EAV) is the causative agent of equine viral arteritis (EVA), a respiratory and reproductive disease of equids. There has been significant recent progress in understanding the molecular biology of EAV and the pathogenesis of its infection in horses. In particular, the use of contemporary genomic techniques, along with the development and reverse genetic manipulation of infectious cDNA clones of several strains of EAV, has generated significant novel information regarding the basic molecular biology of the virus. Therefore, the objective of this review is to summarize cur...
In this study, 198 donor mares of different breeds, ages, and reproductive category were inseminated with fresh, cooled and frozen or frozen and cooled semen at the embryo transfer station or in private artificial insemination centers during 10 breeding seasons. The results of this activity were retrospectively analyzed by Pearson Chi-square test and logistic regression to evaluate factors affecting multiple ovulations, embryo recovery, embryo quality, and embryo diameter. Out of the 661 cycles, 937 ovulations were recorded (mean ovulations/cycle: 1.42 ± 0.58). Ovulation rate and incidence of...
Serum anti-Müllerian hormone (AMH), a marker of equine cryptorchidism, is detectable in intact and cryptorchid stallions but not in geldings because it is secreted from Sertoli cells. A 4-year-old uncastrated Thoroughbred racehorse had no visible testes; therefore, the horse was considered a bilateral cryptorchidism. However, the serum AMH was undetectable (<0.08 ng/ml). Human chorionic gonadotrophin (hCG) stimulating test result indicated that the horse was a gelding. The results of sex chromosomal analysis and sequence analysis of SRY gene suggested that the horse was a genetically-intac...
Cain JL, Norris JK, Swan MP, Nielsen MK.The microbiome plays an important role in health, where changes in microbiota composition can have significant downstream effects within the host, and host-microbiota relationships can be exploited to affect health outcomes. Parasitic helminths affect animals globally, but an exploration of their microbiota has been limited, despite the development of anti-Wolbachia drugs to help control infections with some filarial nematodes. The equine ascarids, Parascaris spp., are considered the most pathogenic nematodes affecting juvenile horses and are also the only ascarid parasite to have developed wi...
Arroyo LG, Gomez DE, Moore A, Papapetrou M, Lillie BN.Our objective was to determine whether equine herpesviruses 1 (EHV-1) viral nucleic acids could be detected immediately after foaling from nasal and vaginal swabs, whole blood, and placental tissue of healthy mares. Unassigned: Nasal and vaginal swabs, EDTA blood, and placental tissue (296 samples) were collected from 74 clinically healthy postpartum broodmares within 24 h after giving birth to live, clinically healthy foals. All samples were tested (PCR) for nucleic acids of neuropathogenic and non-neuropathogenic strains of EHV-1, and all were negative. Unassigned: As EHV-1 was not detected ...
Kern-Allely C, Scott D, Magzamen S, Duncan C.Air pollution is a major global health threat that is expected to worsen, yet its effects on domestic animals remain poorly understood. The objective of this scoping review was to synthesize existing evidence on associations between ambient air pollutants and health outcomes in domestic animals and to identify gaps to guide future research. Unassigned: A scoping review was conducted following the Arksey and O'Malley framework and Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews guidelines with 2 search databases (PubMed and Web of Science) using ...
Thompson JR, Barcalow S, Stark A, Scoggin KE, Conley AJ, Loux SC.Luteinizing hormone (LH) plays a pivotal role in equine reproductive physiology, yet its measurement has traditionally relied on radioimmunoassays (RIA), which present safety, accessibility, and regulatory challenges. This study evaluates the use of a commercially available pregnant mare serum gonadotropin (PMSG) enzyme-linked immunosorbent assay (ELISA) as an alternative for quantifying circulating LH in horses. Given the 100% peptide identity between equine LH and PMSG, we hypothesized that the PMSG ELISA would detect LH with high specificity and sensitivity. Blood samples from healthy, cycl...
de Araujo EAB, Papa FO, de Oliveira Baldini PH, de Paula Freitas-Dell'Aqua C, de Oliveira SN, Silva LFMC, Junior LRPA, Rodrigues LT, Monteiro GA.Despite advances in the method, equine semen cryopreservation still leads to a marked decline in sperm quality, partly attributed to oxidative stress, which motivates the search for lipophilic antioxidants capable of stabilizing the plasma membrane during cooling and freezing. This study performed three experiments to evaluate butylated hydroxytoluene (BHT) as an additive to commercial skim milk-based (Botu-Sêmen) and egg yolk-based (Botu-Crio) extenders. In Experiment 1, a dose-response curve (0.5, 1.0, and 1.5 mM) was performed using stallion semen to assess toxicity and establish a safe ...
Verstraete MH, Kuijpers F, Holl W, Norris J, van Heule M, Martin-Pelaez S, Heard C, Uribe-Salazar J, Armien A, Conley A, De Spiegelaere W....The endometrium is a hormonally responsive tissue that undergoes cyclic remodeling. Although endometrial organoids have been established in several species, detailed characterization remains limited. Here, we assessed the structural and molecular fidelity of equine endometrial organoids across reproductive cycle stages and during extended culture. Organoids were generated from biopsies collected during estrus and diestrus and analyzed using histology, immunohistochemistry, electron microscopy, and bulk- and single-cell RNA sequencing. Organoids formed polarized cystic structures composed of co...