72 EFFECT OF SINGLE-LAYER CENTRIFUGATION WITH EQUIPURE™ ON MOTILITY KINEMATICS OF FROZEN - THAWED DONKEY SPERM

2013 ◽  
Vol 25 (1) ◽  
pp. 183 ◽  
Author(s):  
I. Ortiz ◽  
J. Dorado ◽  
D. Acha ◽  
L. Ramirez ◽  
M. Urbano ◽  
...  

Single-layer centrifugation (SLC) with EquipureTM Bottom Layer has been used to enhance the quality of stallion semen samples; however, no studies have been performed on donkeys. The aim of this study was to determine if SLC with EquipureTM Bottom Layer improves kinematic parameters on frozen–thawed donkey sperm. Semen was collected from 4 Andalusian donkeys by artificial vagina. Three ejaculates from each donkey were centrifuged with EquiproTM, supernatant was removed, and pellet was re-extended in the freezing medium GentTM to a final concentration of 200 × 106 spermatozoa per milliliter. Sperm were slowly cooled to 5°C for 2 h, loaded in 0.5-mL plastic straws, and frozen in liquid-nitrogen vapors. After at least one week of storage, straws were thawed in a water bath at 37°C for 30 s. After thawing, semen samples were divided in 2 aliquots: aliquot 1 was used as such (control) and aliquot 2 was processed by SLC using EquipureTM Bottom Layer. Computer-assisted sperm analysis was performed, and sperm kinematics total motility (%), progressive motility (%), curvilinear velocity (VCL; µm s–1), velocity straight line (VSL; µm s–1), velocity average path (VAP; µm s–1), linearity (LIN; %), straightness (STR; %), wobble (WOB; %), lateral head displacement (ALH; µm), and beat cross frequency (BCF; Hz) were statistically compared using GLM model between frozen–thawed semen samples processed or not with EquipureTM. Results were expressed as mean ± standard error. Significant differences (P < 0.05) were found between SLC-selected and unselected semen for total motility (77.44 ± 5.83 v. 58.89 ± 6.07), progressive motility (76.88 ± 4.52 v. 56.59 ± 5.44), VCL (137.50 ± 0.75 v. 133.0 ± 0.99), LIN (69.43 ± 0.31 v. 68.23 ± 0.41), STR (78.45 ± 0.29 v. 76.90 ± 0.37), WOB (85.06 ± 0.18 v. 83.91 ± 0.26), ALH (2.76 ± 0.01 v. 2.44 ± 0.01), and BCF (9.13 ± 0.05 v. 8.53 ± 0.06), respectively. No significant differences were observed for VSL (102.89 ± 0.70 v. 104.32 ± 0.95) and VAP (123.21 ± 0.71 v. 121.50 ± 0.98). Most of the computer-assisted sperm analysis parameters used in the present study have been previously identified as reliable markers of sperm motility in relation to sperm quality and fertility. It has also been reported that VCL appears to be critical for the formation of the sperm reservoir and penetration of the zona pellucida. In addition, other variables improved in the SLC-selected samples have been described as measure of progressivity (LIN, STR) and spermatozoa vigor (BCF, ALH). These preliminary results suggest an additional option for improving sperm quality in donkey semen doses. In conclusion, SLC with EquipureTM can be used to enhance kinematic parameters on frozen–thawed donkey sperm.

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
P. Perumal ◽  
S. K. Srivastava ◽  
S. K. Ghosh ◽  
K. K. Baruah

The present study was undertaken to assess the motility and velocity parameters of sperm of freezable and nonfreezable ejaculates by computer-assisted sperm analyser (CASA) such as Hamilton-Thorne Semen Analyser IVOS 11 in mithun semen. Fifty ejaculates (twenty-five ejaculates each for freezable and nonfreezable semen ejaculates) were collected from ten matured mithun bulls. CASA parameters, motility parameters such as forward progressive motility (FPM) (%), nonprogressive motility (NPM) (%), total motility (TM) (%), and static sperms (SM) (%); velocity parameters such as curvilinear velocity (VCL) (μm/sec), straight line velocity (VSL) (μm/sec), average path velocity (VAP) (μm/sec), linearity (LIN) (%), straightness (STR) (%), wobble (WOB) (%), amplitude of lateral head displacement (ALH) (μm), and beat/cross-frequency (BCF) (Hz) were measured by CASA analyser. The result revealed that these parameters varied significantly (P<0.05) between the freezable and nonfreezable ejaculates and freezable ejaculates have significantly (P<0.05) higher value than nonfreezable ejaculates. It was concluded that most of the CASA parameters were significantly lower in nonfreezable ejaculates than in freezable ejaculates in mithun and confirmed that the CASA was effective for a quick and objective analysis of motility and velocity parameters in mithun semen.


Animals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1885
Author(s):  
José Néstor Caamaño ◽  
Carolina Tamargo ◽  
Inmaculada Parrilla ◽  
Felipe Martínez-Pastor ◽  
Lorena Padilla ◽  
...  

Genetic resource banks (GRB) preserve the genetic material of endangered, valuable individuals or genetically relevant breeds. Semen cryopreservation is a crucial technique to reach these goals. Thus, we aimed to assess the sperm parameters of semen doses from the native pig breed Gochu Asturcelta stored at the GRB of Principado de Asturias (GRB-PA, Gijón, Spain), focusing on intrinsic and extrinsic (boar, season) factors. Two straws per boar (n = 18, 8–71 months of age) were thawed, pooled, and assessed after 30 and 150 min at 37 °C by CASA (computer-assisted sperm analysis system; motility and kinematic parameters) and flow cytometry (viability, acrosomal status, mitochondrial activity, apoptosis, reactive oxygen species, and chromatin status). The effects of age, incubation, and season on post-thawing quality were determined using linear mixed-effects models. Parameters were on the range for commercial boar breeds, with chromatin status (SCSA: fragmentation and immaturity) being excellent. Incubation decreased sperm quality and functionality. The boar age did not have a significant effect (p > 0.05), but the between-boar variability was significant (p < 0.001). The season significantly affected many parameters (motility, kinematics, viability, acrosomal status, mitochondrial activity), especially after 150 min of incubation. In general, samples collected in spring and summer showed higher quality post-thawing, the lowest in winter. In conclusion, the sperm doses from the Gochu Asturcelta breed stored at the GRB-PA showed excellent chromatin status and acceptable characteristics after thawing. Therefore, boar and seasonal variability in this autochthonous breed could be relevant for cryobank management.


2018 ◽  
Vol 63 (No. 11) ◽  
pp. 429-434
Author(s):  
Zoltán Bokor ◽  
Balázs Csorbai ◽  
Levente Várkonyi ◽  
Zsolt Szári ◽  
Ferenc Fodor ◽  
...  

The effects of a simple saline solution prepared using two different pH (4.4 and 8.5) on sperm motility in burbot were investigated. Results were recorded during a 96-hour chilled storage (4°C) in 24-hour intervals. Measurements were focused on the detailed characteristics of motility using 12 parameters obtained from the Computer-assisted Sperm Analysis (CASA). Significantly higher progressive motility (pMOT), distance average path (DAP), distance curved line, distance straight line (DSL), average path velocity (VAP), curvilinear velocity, straight line velocity, and beat cross frequency (BCF) were observed with the activating solution buffered at pH 8.5 in comparison with pH 4.4. Already after 24 h a significant reduction was measured in pMOT (0 h: 49 ± 24%, 24 h: 12 ± 7%). Similar decreasing tendency was recorded only after 72 h in DAP (0 h: 26 ± 4 µm/s, 72 h: 19 ± 9 µm/s), DSL (0 h: 21 ± 5 µm/s, 72 h: 17 ± 8 µm/s), VAP (0 h: 59 ± 9 µm/s, 72 h: 43 ± 21 µm/s), and BCF (0 h: 28 ± 2 Hz, 72 h: 18 ± 10 Hz). The response of different investigated CASA parameters to different treatments varied in our experiments. According to our studies, numerous burbot sperm motility parameters are sensitive to chilled storage and to low pH of the activating solution. Our results could support the effective sperm quality assessment and successful artificial propagation process in burbot.


2018 ◽  
Vol 30 (1) ◽  
pp. 144
Author(s):  
A. Martins ◽  
F. N. Marqui ◽  
T. E. Cruz ◽  
T. I. H. Berton ◽  
D. G. Souza ◽  
...  

We previously reported that single layer centrifugation (SLC) with Percoll® (GE Healthcare, Uppsala, Sweden) of fresh bovine semen resulted in improved sperm progressive motility and movement, as evidenced by computer-assisted sperm analyzer (CASA) after freezing-thawing. However, no report has been found in the literature on the use of Percoll Plus® (PP; GE Healthcare), a nontoxic colloid, for the same purpose. Thus, this study aimed to verify the effects of SLC-PP before bull sperm freezing on sperm kinematics after cryopreservation. Ejaculates were collected from 3 Nellore bulls (6 from each) using an artificial vagina. After collection, the semen was assessed and pooled, and then 1 billion spermatozoa either diluted [D; 1:2 (v/v)] in freezing extender (FE, without glycerol) or undiluted (UD) was layered on top of a 9-mL column of PP (in 15-mL centrifuge tubes) at concentrations of 70% or 90% to form the 70D, 70UD, 90D, and 90UD treatment groups. Following centrifugation for 13 min at 839 × g [except for the control (C) group], the supernatant was removed and the sperm pellet diluted to 50 × 106 sperm mL−1 in FE medium plus glycerol. Then, frozen–thawed sperm samples were analysed by CASA (MMC Sperm, St. Petersburg, Russia) for the following parameters: total motility (TM, %), progressive motility (PM, %), curvilinear velocity (VCL, µm−1), straight line velocity (VSL, µm s−1), average path velocity (VAP, µm s−1), amplitude of lateral head displacement (ALH, µm), beat cross frequency (BCF, Hz), linearity (LIN, %), and straightness (STR, %). For statistical analyses, ANOVA and Student-Newman-Keuls test were used. Data are presented as mean ± SEM with P < 0.05 taken as significant. No difference was found among the groups for TM, VSL, BCF, and STR. However, the percentage of PM was higher (P < 0.05) in the SLC-selected sperm samples (values ranging from 42.0 ± 7.0 to 47.4 ± 11.4) than in C (28.8 ± 5.0), and ALH was lower in 70UD (1.6 ± 0.12) and 70D (1.7 ± 0.10) than in C (1.9 ± 0.2). Moreover, 70UD (49.0 ± 1.0), 90UD (50.0 ± 3.0), and 90D (50.0 ± 4.0) displayed higher percentage of LIN (P < 0.05) compared with C (45.0 ± 2.0) and 70D (48.0 ± 3.0). On the other hand, similar results were obtained for VCL (from 126.3 ± 8.0 to 130.0 ± 20.5) and VAP (from 82.7 ± 14.5 to 85.1 ± 6.9) in C, 70UD, and 70D, but these values differed (P < 0.05) from those for VCL in 90UD (104.6 ± 10.3) and 90D (97.2 ± 22.0) as well as for VAP in 90UD (72.2 ± 11.0) and 90D (71.8 ± 9.6). These are the first data demonstrating favourable influences of SLC with 70% Percoll Plus® to select distinct sperm subpopulations as evidenced by enhanced PM, LIN, and ALH. Thus, SLC-PP could optimize the production of frozen bull semen by decreasing the number of sperm per insemination dose, and help to circumvent limitations associated with the poor semen quality sometimes found in bulls of high genetic merit. This research was funded by FAPESP # 2015/20986-3, MasterFertility and Tairana Artificial Insemination Station, Brazil.


Animals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1993
Author(s):  
Sabrina Gacem ◽  
Jaime Catalán ◽  
Anthony Valverde ◽  
Carles Soler ◽  
Jordi Miró

In order to optimize the donkey sperm motility analysis by the CASA (Computer Assisted Sperm Analysis)-Mot system, twelve ejaculates were collected from six jackasses. Capillary loaded chamber (CLC), ISAS®D4C depths 10 and 20 µm, ISAS®D4C Leja 20 and drop displacement chamber (DDC), Spermtrack® (Spk) depths 10 and 20 µm were used. Sperm kinematic variables were evaluated using each chamber and a high-resolution camera capable of capturing a maximum of 500 frames/second (fps). The optimum frame rate (OFR) (defined according to curvilinear velocity—VCL) was dependent on chamber type. The highest OFR obtained was 278.46 fps by Spk20. Values for VCL, straight-line velocity (VSL), straightness (STR), amplitude of lateral head displacement (ALH) and beat cross frequency (BCF) were high in DDC and 10 µm depth. In both DDC 10 and 20 µm, the sperm velocities (VCL, VSL, VAP) and ALH values decreased significantly from the centre to the edges, while Wobble and BCF increased. No defined behavior was observed along the CLC. However, all the kinematic variables had a higher value in a highly concentrated sample, in both chamber types. In conclusion, analyzing a minimum of nine fields at 250 fps from the centre to the edges in Spk10 chamber using a dilution of 30 × 106 sperm/mL offers the best choice for donkey computerised sperm motility analysis.


2020 ◽  
Vol 20 (2) ◽  
Author(s):  
Rifai Mustofa ◽  
Aulia Puspita Anugra Yekti ◽  
Aryogi Aryogi ◽  
Dicky Pamungkas ◽  
Rizki Prafitri ◽  
...  

ABSTRAK. Sexing spermatozoa bertujuan untuk mengatur jenis kelamin sesuai harapan. Salah satu metode sexing adalah dengan menggunakan Sentrifugasi Gradien Densitas Percoll. Tujuan dari penelitian ini adalah untuk mengetahui berbagai parameter motilitas menggunakan Computer-assisted Sperm Analysis dan proporsi spermatozoa X dan Y menggunakan metode Sentrifugasi Gradien Densitas Percoll dengan volume awal yang berbeda. Penelitian dilakukan di Loka Penelitian Sapi Potong Grati, Pasuruan, pada bulan Januari sampai Maret 2020. Materi yang digunakan adalah Semen Sapi Peranakan Ongole berumur ±5 tahun dan bobot badan ±700 kg sebanyak 3 ekor, motilitas masa ≥ 2+ dan motilitas individu ≥ 70%. Metode yang digunakan adalah eksperimental menggunakan Rancangan Acak Kelompok (RAK) dengan 3 perlakuan volume saat sexing yaitu P1= 1 ml, P2= 1,5 ml dan P3= 2 ml dengan ulangan 11 kali. Ulangan juga berfungsi sebagai kelompok (block). Hasil penelitian menunjukkan bahwa setelah dilakukan sexing dan pendinginan hingga 5oC persentase motilitas adalah P1:71,02+10,08 %; P2: 79,63+8,65 % dan P3: 83,38+6,67 %, sedangkan motilitas progresif pada P1: 47,68+8,71%; P2: 59,61+7,26 % dan P3: 62,21+6,74%. Curvilinear Velocity (VCL) pada P1: 50,9±7,73 µm/s, P2: 55,2±5,03 µm/s dan P3: 53,2±5,97%. Straight-line Velocity (VSL) pada P1: 20,8±8,19 µm/s; P2: 21,6±6,02 µm/s; P3: 22,1±5,77 µm/s, sedangkan Average Path Velocity (VAP) pada P1: 30,2±7,82 µm/s; P2: 32,5±6,14 µm/s dan P3 : 31,5±6,18 µm/s. Linearity (LIN) pada P1: 40,2±12,26%;P2: 39,1±10,31%;P3: 39,8±7,25%. Straightness (STR) pada P1: 67,2±11,20%; P2: 65,7±10,06%;P3: 67,2±7,92% sedangkan Wobble (WOB) pada P1: 59±9,49%; P2: 58,8±8,63% dan P3: 59,1±7,74%. Kesimpulan dari penelitian adalah motilitas dan motilitas progresif spermatozoa pada sampel dengan volume awal 2 ml lebih baik dibandingkan dengan sampel dengan volume awal 1 ml dan 1,5 ml. (Characteristics of Sexing Spermatozoa Motility in Ongole Cattle with Different Initial Volume) ABSTRACT. Sperm sexing is a technique of sorting a specific type of sperm cell to fertilize the egg cell. One of the sexing methods that can be used for spermatozoa sexing is percoll gradient density centrifugation. This research aims to find out various motility parameters using Computer-assisted Sperm Analysis and the proportion of spermatozoa X and Y using density gradient centrifugation method percoll with different initial volume. The study was conducted at Grati Beef Cattle Research Station, Pasuruan, from January to March 2020. Materials of the study were Semen of 3 Filial Ongole Cattles, aged ± 5 years, with ± 700 kg body weight, mass motility ≥ 2+, and individual motility ≥ 70%. The method used was experimental using a Randomized Group Design with 3 treatment volume when sexing i.e. T0= 1 ml, T1= 1.5 ml dan T2= 2 ml with repetition 11 times. The repetition also functions as groups (blocks). The results showed that after sexing and cooling up to 5oC, the percentage of motility is T0:71.02+10.08 %; T1: 79.63+8,65 % and T2: 83.38+6.67 %. Progressive motility on T0: 47.68+8.71%; T1: 59.61+7.26 % and T2: 62.21+6.74%. Curvilinear Velocity (VCL) on T0: 50.9±7.73 µm/s, T1: 55.2±5.03 µm/s and T2: 53.2±5.97%. Straight-line Velocity (VSL) on T0: 20.8±8.19 µm/s; T1: 21.6±6.02 µm/s; T2: 22.1±5.77 µm/s. The Average Path Velocity (VAP) on T0: 30.2±7.82 µm/s; T1: 32.5±6.14 µm/s and T2 : 31.5±6.18 µm/s. Linearity (LIN) on T0: 40.2±12.26%; T1: 39.1±10.31%;T2: 39.8±7.25%. Straightness (STR) on T0: 67.2±11.20%; T1: 65.7±10.06%; T2: 67.2±7.92%. Wobble (WOB) on T0: 59±9.49%; T1: 58.8±8.63% and T2: 59.1±7.74%. The conclusion of the study is the motility and progressive motility of spermatozoa in samples with an initial volume of 2 ml is better than samples with an initial volume of 1 ml and 1.5 ml.


Respuestas ◽  
2013 ◽  
Vol 18 (2) ◽  
pp. 16-27
Author(s):  
Leonardo Hernández-Corredor ◽  
Alexander Nivia-Osuna ◽  
Daniel Hernández-Villamizar ◽  
Jorge Alexander Rubio-Parada ◽  
Armando Quintero-Moreno

 El estudio evaluó la motilidad espermática y su efecto postdescongelación en semen caprino, en dos medios comerciales (Andromed® y TwoStep®) y diferentes protocolos de congelación (medio completo, con adicción del 10% de yema de huevo, semen centrifugado y sobrenadante seminal), se utilizaron machos de la raza alpina de la Universidad Francisco de Paula Santander Ocaña, el semen fue colectado con electroeyaculador, una vez los medios terminados y parte de los contenidos seminales enteros o centrifugados mezclados, se estabilizó por 2 horas, se envasó en pajillas de 0,5 cc y se congela en vapores de nitrógeno por 10 minutos, las pajillas se llevaron al laboratorio de Andrología de la Universidad del Zulia y por medio del sistema C.A.S.A.(Computer Assisted Sperm Análisis) se evaluaron los parámetros de motilidad como velocidad curvilínea (VCL), velocidad rectilínea (VSL), velocidad lineal (VAP), índice de linealidad (LIN), índice de rectitud (STR), índice de oscilación (ALH), Amplitud media del desplazamiento lateral de la cabeza del espermatozoide (BCF), los datos fueron analizados por medio del procedimiento GLM de SAS versión 9.0; los mejores índices de motilidad (VCL, ALH, BCF) fueron expresados enel tratamiento de contenido seminal centrifugado en medio Andromed®. (p≤0,001))La mejor progresividad espermática (VSL,LIN,STR)se presentó el tratamiento de Semen completo de caprino, criopreservado en medio comercial TwoStep®. ABSTRACT  The study evaluated the effect sperm motility and sperm post-thawing in goats, two commercial means (Andromed ® and Two Step ®) and different freezing protocols (complete medium with 10% addition of the egg yolk, semen centrifuged supernatant and seminal ), we used males of the Alpine race of the University Francisco de Paula Santander Ocaña, semen was collected with electroejaculator once finished media and part of the whole and centrifuged seminal contents mixed, stabilized by two hours, packed in 0.5 cc straws and frozen in nitrogen vapor for 10 min, the straws were taken to the laboratory of Andrology at the University of Zulia and through CASA system (Computer Assisted Sperm Analysis) were evaluated motility parameters such as curvilinear velocity (VCL), straight line velocity (VSL), linear velocity (VAP), linearity index (LIN), straightness index (STR) Oscillation Index (ALH ) average amplitude of the lateral displacement of the sperm head (BCF), the data were analyzed by the GLM procedure of SAS version 9.0, the highest rates of motility (VCL, ALH, BCF) were expressed in the treatment of seminal content centrifugation Andromed ® medium. (p ≤ 0.001)) The best progressive sperm (VSL, LIN, STR) will present the full Semen treatment goats, cryopreserved at Two Step ® commercial medium.Keywords: semen, buck, Andromed, Two step.


2021 ◽  
Vol 33 (2) ◽  
pp. 116
Author(s):  
Y. Pirosanto ◽  
A. Molina ◽  
M. Valera ◽  
J. Dorado ◽  
E. Terán ◽  
...  

Reproductive performance is one of the key factors in livestock production. It is well known that reproductive traits are influenced by several genetic factors, such as the increase of individual inbreeding levels, which are associated with changes in sperm motility and shape in several species. In horses, the increase in inbreeding is a common problem because of the reduction in effective population size and the increase in selection intensity observed in several breeds. However, studies assessing the effect of high levels of inbreeding on the sperm quality of stallions are scarce. In the present study, we aimed to determine the effect of increased inbreeding levels and age on the sperm motility patterns of Purebred Spanish horses (PRE). We performed kinetic characterisation of 557 sperm samples of 82 PRE stallions aged between 3 and16 years, using computer-assisted sperm analysis (Androvision™, Minitube). We evaluated 5 parameters in 6 different fields per sample: curved line velocity (VCL, µm/s), velocity average path (VAP, µm/s), velocity straight line (VSL, µm/s), amplitude of lateral head displacement (ALH, µm), and beat-cross frequency (BCF, Hz). We determined the pedigree-based inbreeding coefficient (Fped) based on ∼300,000 PRE pedigree records to evaluate the inbreeding effect. Individuals were separated into 2 groups: highly inbred (n=339) and lowly inbred (n=218) according to an F value of 12.5%. Differences between groups were analysed using a generalized linear model. The analysis did not show significant differences (P&gt;0.05) in the variables analysed with respect to the age of stallions. However, VAP, VCL, and AHL were lower in highly inbred than in lowly inbred animals (P&lt;0.05), suggesting less velocity and amplitude of head displacement. In the case of BCF, no significant differences (P&gt;0.05) were observed between the two study groups. In conclusion, age did not affect sperm quality parameters in the age group of stallions analysed. In addition, we demonstrated that high inbreeding coefficient reduced the mean velocity and trajectory pattern of spermatozoa in PRE.


2017 ◽  
Vol 62 (No. 6) ◽  
pp. 227-233 ◽  
Author(s):  
J. Šichtař ◽  
A. Nehasilová ◽  
O. Šimoník ◽  
F. Bubeníčková

The aim of the study was to evaluate the effect of two different extenders on sperm characteristic before equilibration and post-thaw in the endangered Old Kladruber stallions. Also, the response of individual stallions to the extenders used was tested. Semen was collected from six stallions every other day within one week. After centrifugation of the collected sperm-rich fraction, the supernatant was removed and sperm pellets were divided to two aliquots; these were diluted either with Gent (Minitube, Germany) or privately manufactured lactose-EDTA-egg yolk extender (Lact). Three cryopreserved insemination doses (IDs) from each extender (Gent and Lact) were prepared for each stallion from one collection (108 samples from six stallions in total). As a parameter of quality, the motility (computer assisted sperm analysis), viability (fluorescence staining), and morphology (eosin/nigrosine staining) were evaluated after dilution with freezing extenders (fresh) and after thawing (frozen-thawed). The different effects of chosen extenders on the quality of fresh semen were only manifested in higher kinematic parameters of sperm when the Lact extender was used. However, in frozen-thawed samples, the Gent extender yielded significantly better results in all of the evaluated parameters. The representation of sperm subpopulation was significantly influenced by extender in fresh as well as frozen-thawed samples; moreover, we found a significant effect of freezing on the distribution of these subpopulations. The response of individual stallions to chosen extenders was evident in the different quality of fresh as well as frozen-thawed IDs; Gent extender yielded better frozen-thawed IDs. Based on our results, among others describing quality parameters of ejaculate in endangered Old Kladruber stallions, we can recommend using Gent extender for the production of frozen-thawed IDs.  


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