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Topic:Semen Analysis

Semen analysis involves the evaluation of semen quality to assess reproductive potential and health in horses. This process typically includes the examination of several parameters such as sperm concentration, motility, morphology, and volume. Semen analysis is used in breeding programs to determine the fertility of stallions and to identify any reproductive issues. The collected data can assist in making informed decisions about breeding management and interventions. This page compiles peer-reviewed research studies and scholarly articles that explore the methodologies, findings, and implications of semen analysis in equine reproduction.
Comprehensive Integrated Analyses of Proteins and Metabolites in Equine Seminal Plasma (Horses and Donkeys).
Proteomes    July 4, 2025   Volume 13, Issue 3 33 doi: 10.3390/proteomes13030033
Wen X, Bou G, He Q, Liu Q, Yi M, Ren H.The reproductive ability of equine species is a critical component of equine breeding programs, with sperm quality serving as a primary determinant of reproductive success. In this study, we perform an integrative analysis of proteomics and metabolomics in seminal plasma to identify proteins and metabolites associated with sperm quality and reproductive ability in equine species. Methods: We utilized the CEROS instrument to assess the morphology and motility of sperm samples from three horses and three donkeys. Additionally, we statistically analyzed the mating frequency and pregnancy rates in...
Analysis of Motion Characteristics and Plasma Membrane Intactness (Viability) in Sperm from Domestic Animals.
Methods in molecular biology (Clifton, N.J.)    July 2, 2025   Volume 2954 241-259 doi: 10.1007/978-1-0716-4698-4_14
Hernández-Avilés C.Sperm quality analysis using computer-assisted sperm analysis (CASA) systems and fluorescence-based techniques has become common in the animal reproduction industry, particularly for large animals (i.e., bovine, porcine, equine). In this chapter, the methods commonly utilized in the author's laboratory to examine sperm motion characteristics via CASA and plasma membrane intactness by flow cytometry will be described. These include methods to properly dilute fresh (stallions, bulls, boars), cool-stored (stallions, boars), or frozen/thawed (stallions, bulls, boars) sperm for assessment of sperm ...
Influence of Cryopreservation on the Acrosome Reaction in Hucul Stallion Spermatozoa.
Animals : an open access journal from MDPI    June 28, 2025   Volume 15, Issue 13 1915 doi: 10.3390/ani15131915
Bugno-Poniewierska M, Bielecka M, Pietras N, Kij-Mitka B, Podstawski Z, Długosz B.The Hucul horse is a Polish primitive breed with a small population size, which highlights the importance of preserving the genetic resources. The cryopreservation of semen is essential for creating gene banks, but its effect on the acrosome reaction in Hucul stallions has not yet been investigated. The acrosome reaction is one of the most important physiological events associated with the fertilization process. Therefore, our goal was to determine the level of acrosome reaction in chilled and frozen/thawed Hucul stallion semen using the FluoAcro test and the SCA semen analysis system. We foun...
Effect of Centrifugation of Stallion Semen Through a Low Density Colloid Prior to Freezing on Sperm Cryosurvival.
Animals : an open access journal from MDPI    June 25, 2025   Volume 15, Issue 13 1881 doi: 10.3390/ani15131881
Al-Kass Z, Morrell JM, Ntallaris T.Sperm quality is adversely affected by cryopreservation due to the increased production of reactive oxygen species, which affects the integrity of sperm membranes, motility, and DNA fragmentation. Three methods for removing seminal plasma, washing (centrifuging extended semen at 800× for 10 min) and Single Layer Centrifugation with high or low density Equicoll, were used to prepare 29 ejaculates from ten stallions for freezing. Sperm quality parameters (kinematics, plasma membrane integrity, superoxide and hydrogen peroxide production, mitochondrial membrane potential, and DNA fragmentation)...
Catalase in Unexpected Places: Revisiting H2O2 Detoxification Pathways in Stallion Spermatozoa.
Antioxidants (Basel, Switzerland)    June 12, 2025   Volume 14, Issue 6 doi: 10.3390/antiox14060718
Medica AJ, Swegen A, Seifi-Jamadi A, McIntosh K, Gibb Z.Oxidative stress plays a critical role in regulating sperm function, yet species-specific antioxidant mechanisms remain poorly understood. This study compared hydrogen peroxide (H2O2) tolerance in horse and human sperm and investigated the roles of catalase and glutathione peroxidase (GPx) in horses. A H2O2 dose-response assay (0-2000 µM) showed that horse sperm were significantly more resistant to oxidative damage, with an IC50 for progressive motility over 14-fold higher than that of human sperm (391.6 µM vs. 27.3 µM). Horse sperm also accumulated more intracellular H2O2 without loss of m...
Advancements in microfluidic and electrophoretic techniques for stallion sperm isolation.
Reproduction, fertility, and development    June 2, 2025   Volume 37 doi: 10.1071/RD25045
Medica A, Aitken RJ, Swegen A, Gibb Z.Context Equine reproductive technologies are crucial for overcoming challenges in natural fertilisation, particularly in sub-fertile stallions and breeding programs focused on genetic conservation and performance enhancement. Assisted reproductive technologies (ARTs), such as artificial insemination (AI), intracytoplasmic sperm injection (ICSI), and in vitro fertilisation (IVF), improve fertility outcomes and enable breeding across geographical distances. Aims This review examines sperm isolation techniques used in ART, evaluating their efficacy, limitations, and potential to enhance reproduct...
Thermal comfort and seminal traits in stallion reproduction: New methods to understand these relationships.
Journal of equine veterinary science    May 27, 2025   Volume 151 105615 doi: 10.1016/j.jevs.2025.105615
Maria Feitosa Ribeiro L, Bersot Gomes JV, Hernando Ortiz Vega W, da Silva Alves A, Netto Machado M, Junio Wutke L, Raquel Quirino C....Stallion breeding is mostly based on desirable phenotypic traits, with little consideration for semen quality. Objective: To identify relationships among semen parameters in stallions using a non-invasive, integrative approach across summer and winter seasons. Methods: Twenty-four stallions were evaluated, in which semen collections, testicular thermography, and Doppler velocimetry of the testicular artery by Doppler ultrasonography were performed, in addition to the measurement of physiological, environmental, and heat stress parameters, both in winter (coat weather) and summer (T-shirt weath...
Comparative Analysis of Proteomic Characteristics in Seminal Plasma Between Horses and Donkeys.
Animals : an open access journal from MDPI    May 23, 2025   Volume 15, Issue 11 1532 doi: 10.3390/ani15111532
Wen X, Ren H, He Q, Yi M, Ulaangerel T, Bou G.Horses and donkeys, as integral members of the equine family, exhibit distinct reproductive capabilities and characteristics. Seminal plasma, the fluid component of semen, contains a variety of proteins that play critical roles in sperm function and fertility. This study aimed to systematically compare the protein profiles in the seminal plasma of horses and donkeys, thereby elucidating the molecular differences between these two species. The study utilized 4D-DIA proteomics technology to analyze seminal plasma from horses and donkeys and further validated key proteins through Western blot. Ou...
The relationship between post-thaw sperm quality parameters and blastocyst production following Intracytoplasmic Sperm Injection (ICSI) of in vitro-matured equine oocytes.
Theriogenology    May 20, 2025   Volume 244 117500 doi: 10.1016/j.theriogenology.2025.117500
Hernández-Avilés C, Ramírez-Agámez L, Love CC.In vitro production of equine embryos by Intracytoplasmic Sperm Injection (ICSI) is commonly utilized to maximize the availability of stallion sperm, particularly from stallions with limited semen supply. The relationship between standard measures of sperm quality in frozen/thawed semen (i.e., sperm motility, normal morphology, DNA quality) and embryo production after ICSI of in vitro-matured equine oocytes has not been thoroughly studied. In this study, frozen/thawed semen from 47 stallions utilized in a commercial ICSI program was analyzed for post-thaw sperm total and progressive motility (...
Metformin and rosiglitazone affect motility, lipid peroxidation and mitochondrial activity of thawed equine spermatozoa.
Journal of equine veterinary science    April 11, 2025   Volume 149 105570 doi: 10.1016/j.jevs.2025.105570
Usuga A, Vergara AK, Tobón MC, Vargas S, Rojano B, Restrepo G.Maintaining sperm energy homeostasis in vitro is very important to improve the efficacy of stallion sperm preservation. Equine spermatozoa preferentially utilize oxidative phosphorylation over glycolysis to generate ATP. Metformin and rosiglitazone are antidiabetic compounds that enhances metabolic flexibility and glucose utilization. The aim of this study was to evaluate metformin and rosiglitazone supplementation of the freezing medium on quality and oxidative status of thawed stallion semen. A total of 15 ejaculates from five horses were collected and supplemented before freezing with metfo...
Association between sperm DNA fragmentation and fertility parameters in farm animals: a systematic review and meta-analysis.
BMC veterinary research    March 26, 2025   Volume 21, Issue 1 204 doi: 10.1186/s12917-025-04652-9
Abah KO, Ligocka-Kowalczyk Z, Itodo JI, Ameh G, Partyka A, Nizanski W.Accurately predicting male fertility is crucial for the animal breeding industry due to its significant economic implications. Existing literature suggests that mammalian fertility is partially dependent on sperm DNA integrity. However, routine semen analysis often fails to detect DNA damage and does not consistently correlate with field fertility outcomes. While assessing sperm DNA integrity provides valuable biological insights, its role in diagnosing animal infertility remains uncertain. Results: This meta-analysis evaluated the association between sperm DNA fragmentation (SDF) and fertilit...
Sperm Motility Evaluation in Stallion Fresh, Cooled and Frozen Semen Using a Portable Computer-Assisted Sperm Analysis System.
Reproduction in domestic animals = Zuchthygiene    March 20, 2025   Volume 60, Issue 3 e70052 doi: 10.1111/rda.70052
Brito LFC.Semen analysis is an important laboratory diagnostic test for stallions. Evaluation of sperm motility is integral to basic semen analysis and results are important for breeding management and clinical practice. Computer-assisted sperm analysis (CASA) allows objective sperm motility evaluation and increases analytical precision. The objective of the present study was to validate a portable CASA system (AndroScope). Fresh/cooled semen samples (33 ejaculates, 18 stallions) and frozen semen (40 ejaculates and one epididymal flush, 27 stallions) were evaluated using the AndroScope and the IVOS II C...
Cryoprotective effect of zinc and gold nanoparticles during cooling and freeze-thawing on Marwari stallion sperm parameters and reactive oxygen species production.
Cryo letters    March 16, 2025   Volume 45, Issue 6 361-369 
Sultan T, Chaudhary AK, Mehta JS, Mehra R, Manuja A, Talluri TR, Bhattacharya TK.Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. Objective: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. Methods: A total of 20 ejaculates from four Marwari ...
Concentrations of arsenic (As), cadmium (Cd) and lead (Pb) in blood, hair and semen of stallions in Finland.
Journal of trace elements in medicine and biology : organ of the Society for Minerals and Trace Elements (GMS)    March 14, 2025   Volume 89 127633 doi: 10.1016/j.jtemb.2025.127633
Oztas T, Akar M, Virkanen J, Beier C, Goericke-Pesch S, Peltoniemi O, Kareskoski M, Björkman S.Heavy metal contamination poses significant environmental and health risks to both humans and animals. This study investigates the concentrations of arsenic (As), cadmium (Cd), and lead (Pb) in blood, hair, and semen samples collected from 16 breeding stallions in Western Finland to assess whether concentrations in hair and serum samples represent concentrations in semen. The analysis was conducted using an inductively coupled plasma mass spectrometry (ICP-MS) system. Results showed that hair samples exhibited the highest concentrations of heavy metals, particularly Pb and As, while semen show...
Results of the “test-freeze” approach in a commercial program of stallion sperm cryopreservation and the relationship between pre-freeze sperm quality and “freezability.”.
Theriogenology    March 3, 2025   Volume 238 117373 doi: 10.1016/j.theriogenology.2025.117373
Hernández-Avilés C, Varner DD, Ramírez-Agámez L, Samper JC, Love CC.In the current study, we report the effect of different commercially available semen freezing extenders utilized for the "test-freeze" procedure for 13 years (2010-2023) as part of a commercial program of stallion sperm cryopreservation. Ejaculates obtained from sexually active and healthy stallions (n = 124) were cryopreserved using up to five commercially available semen freezing extenders (Lactose-EDTA [LE], MFR5, CryoMax LE [CMLE], CryoMax MFR5 [CMMFR5] or BotuCrio [BC]). Post-thaw sperm motility (total motility - TM [%]; progressive motility - PM [%]; and curvilinear velocity - VCL [μm...
DSP-1, the major fibronectin type-II protein of donkey seminal plasma is a small heat-shock protein and exhibits chaperone-like activity against thermal and oxidative stress.
Biochimica et biophysica acta. Proteins and proteomics    February 14, 2025   141064 doi: 10.1016/j.bbapap.2025.141064
Alim S, Cheppali SK, Pawar SS, Swamy MJ.Fibronectin type-II (FnII) proteins are major constituents in the seminal plasma of many mammals and play a crucial role in sperm capacitation. Additionally, the seminal FnII proteins from bull and horse exhibit chaperone-like activity (CLA), by acting as small heat shock proteins (shsps). The present work demonstrates that the major FnII protein of donkey seminal plasma, DSP-1 exhibits CLA with broad specificity and protects various client proteins such as alcohol dehydrogenase, lactate dehydrogenase and enolase against thermal and oxidative stress. Binding of phosphorylcholine (PrC) - the he...
The inability of spectral Doppler ultrasonography to identify stallions with testicular dysfunction.
Journal of equine veterinary science    February 4, 2025   105367 doi: 10.1016/j.jevs.2025.105367
Pozor MA, Macpherson ML, Kelleman AA, Smith H, McNaughten JW.This retrospective study aimed to validate the usefulness of spectral Doppler ultrasonography in diagnosing testicular dysfunction in stallions. The first part of the study included a pony stallion with age-related testicular degeneration (18 - 21 yrs. old). Testicular dimensions, spectral Doppler parameters of testicular blood flow, and semen parameters were obtained numerous times from this pony over four consecutive years. While testicular volume decreased dramatically, and the stallion became azoospermic, there were no changes in any of the spectral Doppler parameters of testicular blood f...
Laparoscopic Inguinal Hernioplasty with a Polyether Ether Ketone Anchoring Device in Intact Male Horses Does Not Compromise Testicular Perfusion, Sperm Production or Motility Characteristics.
Animals : an open access journal from MDPI    January 31, 2025   Volume 15, Issue 3 doi: 10.3390/ani15030402
Vitoria A, Barrachina L, Romero A, Fuente S, de Blas I, Gil L, Vázquez FJ.A new surgical technique using a polyether ether ketone (PEEK) anchoring device for testicle-sparing laparoscopic inguinal hernioplasty in stallions was described in 2023 and is known as the PEEK harpoon technique (PHT). In breeding stallions, it is essential that the surgery is effective in preventing inguinal hernia but also that it does not impair the testicular function. This study aims to evaluate whether the PHT may affect testicular function. To achieve that, changes in the testicular blood flow, sperm production and motility characteristics were assessed 28 days after use of the PHT. S...
Curcumin-loaded niosomal nanocarriers offer a promising approach to improve quality characteristics, apoptotic gene expression, and flow cytometry assessments of stallion spermatozoa after thawing.
Cryobiology    December 29, 2024   Volume 118 105188 doi: 10.1016/j.cryobiol.2024.105188
Nasiri-Foomani N, Hassani S, Najafi M, Samadi F.The optimization of cryopreservation media to reduce oxidative damage on post-thaw spermatozoa is crucial. This research aimed to assess the antioxidant properties of curcumin-loaded niosomal nanocarriers (CurLNN) on the functional characteristics, the relative expression of apoptotic genes, and flow cytometry assessments of apoptotic-like changes, reactive oxygen species production (ROS), mitochondrial membrane potential, and chromatin integrity in stallion spermatozoa following thawing. Twenty-five ejaculates were diluted in INRA96 freezing media supplemented with 20 μM of either curcumin ...
The use of sex-sorted semen in horses.
Journal of equine veterinary science    December 5, 2024   Volume 145 105251 doi: 10.1016/j.jevs.2024.105251
Samper JC, Hernandez Aviles JC, Ramirez-Agamez LF, Love CC, Gonzalez-Marin C, Fleury P, Dini P, De La Fuente A, Foss R, Campos FL, Ross PJ.The application of sex-sorted semen in horses has historically lagged the bovine industry due to differences in the reproductive physiology and grater variability in equine semen quality. Recent advancements, including SuperGen™ sorters and Ultraplus™ semen processing methods developed by STgenetics® (Navasota, Texas), have significantly improved the efficiency of the sex-sorting process and reduced the sperm damage previously reported. To facilitate the broader use sex-sorted semen in the equine industry, it is essential to address challenges such as shipping cooled semen to a central so...
Niosomal nanocarriers loaded with artemisinin has potential to enhance the functional characteristics of cryo-preserved equine spermatozoa.
Animal reproduction science    November 26, 2024   Volume 272 107653 doi: 10.1016/j.anireprosci.2024.107653
Abbasi A, Nouri H, Samadi F.Cryopreservation is a crucial method for the preservation of genetic materials. Nevertheless, this technique can have adverse effects due to cryo-oxidative damage. The primary objective of this study was to investigate the cryo-protective effects of niosomal nanocarriers loaded with artemisinin (NN-Art) on the functional attributes of equine spermatozoa. The parameters examined included sperm motility and kinematics through computer-assisted sperm analysis (CASA), plasma membrane integrity via the hypoosmotic swelling test, viability using the eosin-nigrosin staining technique, morphology with...
Prolonged maintenance of stallion semen by optimization of cooling conditions.
Journal of equine veterinary science    November 19, 2024   Volume 144 105243 doi: 10.1016/j.jevs.2024.105243
Guertin JE, Losano JA, Salazar S, Callaham J, Daigneault BW.Bottlenecks to the success of equine assisted reproductive technologies (ART) include suboptimal conditions for prolonged storage of stallion sperm. Shipped stallion sperm are transported in cooling devices designed to maintain temperature for up to 48 h. Increasing the storage time of cooled semen while maintaining acceptable motility would relieve logistical ART challenges. Experiments were conducted to test the hypothesis that external regulation of shipment container temperature would prolong storage time of cooled stallion semen. Initial experiments determined the effect of pre-freezing c...
Optimizing equine sperm quality: an alternative to single layer centrifugation for sperm isolation.
Reproduction & fertility    November 11, 2024   Volume 5, Issue 4 e230081 doi: 10.1530/RAF-23-0081
Medica AJ, Gibb Z, Aitken RJ.In vitro semen purification techniques have been developed that seek to mimic the in vivo selection process in order to generate the highest possible chance of oocyte fertilization following artificial insemination. Numerous methods have been developed to isolate functional spermatozoa for artificial insemination, yet only one method, single-layer centrifugation using commercial preparations like EquiPure, has been widely employed. In this study, we have introduced a novel approach for isolating spermatozoa and compared their quality to those isolated using EquiPure. The AI port system (Mempha...
Unraveling the genetic and physiological potential of donkeys: insights from genomics, proteomics, and metabolomics approaches.
Mammalian genome : official journal of the International Mammalian Genome Society    November 7, 2024   doi: 10.1007/s00335-024-10083-y
Parsad R, Bagiyal M, Ahlawat S, Arora R, Gera R, Chhabra P, Sharma U.Donkeys (Equus asinus) have played a vital role in agriculture, transportation, and companionship, particularly in developing regions where they are indispensable working animals. The domestication of donkeys marked a significant turning point in human history, as they became essential for transportation, agriculture, and trade, especially in arid and semi-arid areas where their resilience and endurance were highly valued. In modern society, donkeys are indispensable due to their diversified applications, including meat, dairy, medicine, and functional bioproducts, supporting economic, cultura...
Spermatozoal acrosome dysfunction and its role in stallion subfertility.
Journal of equine veterinary science    October 26, 2024   Volume 143 105213 doi: 10.1016/j.jevs.2024.105213
Hernández-Avilés C, Ramírez-Agámez L, Varner DD, Raudsepp T, Love CC.Cases of stallion subfertility due to acrosome dysfunction have been recognized since the 1990s. While some of these were observed in stallions with reduced sperm motility and morphology, a more severe form has been reported in stallions with normal-to-excellent sperm quality parameters, which is also uniquely observed in individuals of the Thoroughbred registry. These stallions carry a susceptibility genotype (A/A-A A in the gene FKBP6, exon 5) for Impaired Acrosomal Exocytosis (IAE). Current clinical observations from our group have identified a few highly subfertile stallions from other bre...
Prolonged incubation of frozen-thawed equine spermatozoa for in vitro fertilization: A preliminary study using low temperature and INRA96 medium.
Reproduction in domestic animals = Zuchthygiene    October 14, 2024   Volume 59 Suppl 3 e14593 doi: 10.1111/rda.14593
Luis-Calero M, Muñoz-García CC, Fernández-Hernández P, Macías-García B, González-Fernández L.A protocol for conventional in vitro fertilization (IVF) in horses using fresh semen has been described, using a prolonged incubation in FERT-TALP medium (22 h) at 38.2°C in the presence of penicillamine, hypotaurine and epinephrine (PHE). Our work aimed to develop a protocol that maintains quality parameters in frozen-thawed equine spermatozoa incubated for 22 h in the presence of PHE using different media (FERT-TALP and INRA96) and incubation temperatures (30 and 38.2°C). Twelve frozen ejaculates from four stallions were thawed and then incubated in either FERT-TALP or INRA96 with PHE...
Effect of refreezing extender on stallion sperm quality and embryo production after intracytoplasmic sperm injection.
Theriogenology    October 9, 2024   Volume 231 29-35 doi: 10.1016/j.theriogenology.2024.10.006
Brito LFC, Felix MR, Linardi RL, Martinez de Andino EV, Balamurugan NS, Hernández-Avilés C, Hinrichs K.Intracytoplasmic sperm injection (ICSI) is a valuable assisted reproduction technology in clinical practice, especially when semen availability is limited. Since the number of sperm required per ICSI cycle is much less than the number of sperm available in a standard straw of frozen semen, refreezing semen at lower sperm concentrations could yield multiple straws for ICSI use. However, there is little data on the effect of sperm refreezing on ICSI outcomes, especially on the effect of extender used for refreezing. The objective of the present study was to evaluate the effect of refreezing exte...
Effect of protein acetylation on capacitation of stallion sperm.
Journal of equine veterinary science    September 18, 2024   Volume 142 105195 doi: 10.1016/j.jevs.2024.105195
Aguiar LH, Pinto CRF.Sperm capacitation is considered the main factor limiting conventional in vitro fertilization (IVF) in horses. A recent scientific breakthrough in sperm processing for IVF in horses has resulted in embryos and foals being produced; however, various aspects of the IVF process remain to be fully elucidated. Lysine acetylation has been shown to play a role in sperm capacitation in several species and the objective of this study was to detect and evaluate this process in the horse. Ejaculates of two stallions were collected and incubated in different conditions with deacetylase inhibitors to induc...
Pre- and Post-Thaw Addition of L-Carnitine and Pyruvate: Effect on Stallion Sperm Parameters.
Reproduction in domestic animals = Zuchthygiene    September 15, 2024   Volume 59, Issue 9 e14720 doi: 10.1111/rda.14720
Caldevilla M, Ferrante A, Neild DM.The addition of antioxidants to cryopreservation media reportedly improves sperm post-thaw quality and reproductive performance after artificial insemination. Therefore, the objectives of this study were to evaluate if the addition of L-carnitine and pyruvate to freezing media, or their addition to samples after thawing, improves the post-thaw quality of equine spermatozoa. Thus, in Experiment 1, stallion semen samples were cryopreserved in: (1) EDTA-glucose-based extender with 20% egg yolk and 5% dimethylformamide (EDTA control); (2) skim milk-based extender with 20% egg yolk and 5% dimethylf...
Factors affecting pregnancy rates in mares bred with cryopreserved semen.
Journal of equine veterinary science    August 14, 2024   Volume 141 105167 doi: 10.1016/j.jevs.2024.105167
Pasch L, Stefanovski D, Dobbie T, Lewis G, Turner RM.Historically, 8 × 0.5 ml straws, containing approximately 800 million sperm and 250 million progressively motile sperm were provided as a single 'breeding dose' of cryopreserved stallion semen. With the use of deep horn artificial insemination, there is a trend to reduce the number of 0.5 ml straws sold as a breeding dose, sometimes down to as little as one straw. Our aims were to determine if the number of straws provided as a breeding dose, as well as other mare, stallion and management factors, have an impact on pregnancy outcome in mares inseminated with cryopreserved semen. Unexpectedly,...