scholarly journals 7 HETEROSPERMIC INSEMINATION AT TWO SPERM CONCENTRATIONS IN TIMED AI: CASA SEMEN PARAMETERS AND PREGNANCY RATES

2005 ◽  
Vol 17 (2) ◽  
pp. 154 ◽  
Author(s):  
A. Albrecht ◽  
R. Cavia ◽  
G. Larraburu ◽  
F. Garcia Migliaro ◽  
G. Brogliatti
Keyword(s):  
Artificial Insemination ◽  
Semen Analysis ◽  
Pregnancy Rates ◽  
Semen Parameters ◽  
Computer Assisted ◽  
High Concentration ◽  
Bull Semen ◽  
Motile Cells ◽  
Timed Artificial Insemination ◽  
Motility Parameters

The latest entry in the field of semen evaluation is computer assisted semen analysis (CASA). Heterospermic insemination has been used to increase pregnancy rates from low fertile bulls. The objective of this study was to evaluate, with the aid of CASA, heterospermic semen characteristics and pregnancy rates using different concentrations of bull semen in a timed artificial insemination protocol. Semen was collected from two bulls of known fertility by artificial vagina and all CASA motility parameters were evaluated individually and combined. Straws were filled using a semi-defined semen extender (Andromed, Minitüb, Tiefenbach, Germany) as follows: single bull A and single bull B (12 × 106 of progressive motile cells after thawing); Mixed bull semen: A + B (12 × 106 of progressive motile cells after thawing) and Supermix bull semen: A + B (28 × 106 of progressive motile cells after thawing). All cows received a P4 intravaginal device (DIB, Syntex, Argentina) and 2 mg of EB i.m. (Syntex) on Day 0, 500 mg cloprostenol (Estroplan, Syntex) at the time of DIB removal (Day 8), and 1 mg EB i.m. on Day 9. Fixed-time insemination (FTAI) was performed at 52 to 56 h after DIB removal. A total of 249 cows were randomly allocated to be inseminated with bulls A and B (n = 76), with Mixed A + B (n = 87), and with Supermixed A+B at a high concentration (n = 86) by a single inseminator. Pregnancy rates were evaluated at 38 days after insemination by transrectal ultrasonography. Means and standard deviations or each characteristic were calculated, compared, and statistically analyzed. The following sperm motility parameters were determined with the Ceros 12.1 sperm analyzer (Hamilton Thorne Biosciences, Inc., Beverly, MA, USA) on at least 1000 spermatozoa: velocity average path (VAP), velocity straight line (VSL), curvilinear velocity (VCL), amplitude lateral head (ALH), beat cross frequency (BCF), straightness (STR), linearity (LIN), and percentage of rapid or static cells. There were no significant differences (P > 0.05) in VAP, VSL, VCL, ALH, STR, or LIN. There was a numerically higher percentage of rapid cells in the Supermix semen. Pregnancy rate from bulls A and B was 61% and from Mixed A + B 60%, while that from Supermixed A + B was 69%. Results from the analysis indicate that semen concentration is an important element to be considered in a timed artificial insemination program. Numerically higher pregnancy rates were obtained with double semen concentration in the straw. More research is required to evaluate the interaction between different breeds within a timed artificial insemination program. This research was supported by Centro Genético Bovino de EOLIA sa and Syntex sa Argentina.

84 EVALUATION OF BULL SEMEN AT 1 H VS. 48 H OF POST-FROZEN STABILIZATION TIME

2006 ◽  
Vol 18 (2) ◽  
pp. 150
Author(s):  
G. M. Brogliatti ◽  
G. Larraburu ◽  
R. Cavia ◽  
M. E. Carini
Keyword(s):  
Liquid Nitrogen ◽  
Artificial Insemination ◽  
Semen Analysis ◽  
Computer Assisted ◽  
Stabilization Time ◽  
Bull Semen ◽  
Straight Line ◽  
Semen Extender ◽  
Lateral Head

The process of cryopreservation of bull semen in liquid nitrogen at −196°C is usually carried out after 3 to 6 h of refrigeration at 4°C post-collection. To guarantee the quality of the final product, the frozen straws are evaluated after cryopreservation. The seminal samples are usually stabilized during 48 h before being analyzed (Hafez, Reproduction and Artificial Insemination in Animals, 1989); this would retard the possible commercialization. The objective of the present study was to determine motility parameters and viability of semen doses stabilized by 1 h or more than 48 h in liquid nitrogen at −196°C. A total of 122 ejaculated from 23 different adult bulls (Angus, Brangus, Braford, and Hereford) were evaluated in an artificial insemination center between January and April 2005. The semen was diluted in a semi-defined semen extender (Andromed, Minitub, Germany) and frozen in an automatic freezer (Digicool, IMV, France). Parameters of velocity average path (VAP, μm/s), velocity straight line (VSL, µm/s), amplitude lateral head (ALH, µm), linearity (LIN, %), percentage of rapid cells (RAPID, %), and viability (VIA, %) were determined by Computer Assisted Semen Analysis (CASA, HTM-ceros 12.1, Berkeley, CA, USA). The obtained results were analyzed statistically with T Student and are summarized in Table 1. The results indicate that there is no difference in the velocity of the spermatozoa evaluated 1 h or 48 h post-frozen. There is no difference in VAP, VSL, movement of amplitude lateral head (ALH), or linearity (LIN). The percentage of viable spermatozoa was not affected in either group. Statistical analysis indicates that there is no difference (P > 0.05) in any of the evaluated parameters. The results demonstrate that spermatic motility and viability of frozen bull semen could be evaluated before 48 h post-frozen. This allows reduction of the time between freezing and evaluation and immediate availability of the bull straws. Table 1. Parameters of motility and viability at 1 h vs. 48 h of post-frozen stabilization time This research was supported by Centro Genético Bovino EOLIA S.A.

scholarly journals 12 CASA PARAMETERS OF FRESH BULL SEMEN COLLECTED BY ARTIFICIAL VAGINA OR ELECTROEJACULATION IN ARGENTINA

2005 ◽  
Vol 17 (2) ◽  
pp. 156 ◽  
Author(s):  
G. Brogliatti ◽  
F. Garcia Migliaro ◽  
R. Cavia ◽  
G. Larraburu ◽  
A. Albrecht
Keyword(s):  
Semen Analysis ◽  
Glass Tube ◽  
Computer Assisted ◽  
Bull Semen ◽  
Straight Line ◽  
Beef Bulls ◽  
Semen Extender ◽  
Artificial Vagina ◽  
Lateral Head ◽  
Motility Parameters

The latest entry in the field of semen evaluation is computer assisted semen analysis (CASA). Its greatest advantages are elimination of the subjective nature of routine semen evaluation and the addition of detailed motion analysis unquantifiable by visual examination. The objective of this study was to evaluate CASA motility parameters of fresh bull semen collected by artificial vagina (AV) or electroejaculation (EE) from a total of 56 beef different bulls. Semen samples from a total of 45 beef bulls were collected by AV from winter to the end of spring (740 collections), and from 11 beef bulls by EE (120 collections) in the same period. First and second AV collections were analyzed as individual data. EE collection was performed only one. Means and standard deviations for each characteristic were calculated, compared, and statistically analyzed. A sample of the collection was diluted 1:20 in a semi-defined semen extender (Andromed, Minitüb, Tiefenbach, Germany) and held in a glass tube at 36°C for 5 min before analysis. The sample was loaded into 20-μm chambers, and six microscope fields from each chamber were analyzed. The following sperm motility parameters were determined with the Ceros 12.1 sperm analyzer (Hamilton Thorne Biosciences, Inc., Beverly, MA, USA) on at least 1000 spermatozoa:concentration (CONC), velocity average path (VAP), velocity straight line (VSL), curvilinear velocity (VCL), amplitude lateral head (ALH), beat cross frequency (BCF), straightness (STR), linearity (LIN), and percentage of rapid or statics cells. There were no significant differences (P > 0.05) in VAP, VSL, VCL, ALH, STR, LIN, and the percentage of rapid and static cells of semen collected by AV or EE. The concentration (sperm/mL) of the AV-collected sperm was significantly higher than for the sperm collected by EE. Results from the analysis indicate that semen collected by artificial vagina have motility characteristics similar to those collected by electroejaculation. More research needs to be done to evaluate motility parameters of frozen/thawed semen collected by electroejaculation and by artificial vagina. This research was supported by Centro Genético Bovino de EOLIA sa Argentina.

162 FREEZING OF SEMEN FROM ENDANGERED ASTURIANA DE LA MONTAÑA BULLS IN ZWITTERONIC LIPIDS-BASED EXTENDERS

2008 ◽  
Vol 20 (1) ◽  
pp. 161 ◽  
Author(s):  
C. Tamargo Miguel ◽  
S. S. Pérez-Garnelo ◽  
P. Beltrán Breña ◽  
A. T. Palasz ◽  
J. De la Fuente ◽  
...  
Keyword(s):  
Sperm Motility ◽  
Semen Analysis ◽  
Egg Yolk ◽  
Semen Parameters ◽  
Computer Assisted ◽  
Progressive Motility ◽  
Bull Semen ◽  
Straight Line ◽  
Before And After ◽  
Arcsine Transformation

This experiment was designed to test the efficacy of 2 different preparation protocols of zwitteronic soyabean-origin lipids for the production of lipidsglycerol liposomes for use in bull semen cryopreservation. Lipids liposomes were prepared at 10% concentration in Tris buffer by 1. highpressure homogenization (Panda 2K, Parma, Italy) and then 8% glycerol were added, extender-1 (E-1); Lipids were homogenized together with glycerol, extender-2 (E-2). Bioxcell extender (E-3) was used as control. Semen was collected 3 times from 3 endangered Asturiana de la Monta�a bulls by the means of an artificial vagina. Ejaculates with at least 70% motility were processed further by a standard freezing protocol used in our AI station. Semen was diluted at 37�C with each of the 4 extenders to a concentration of 92 � 106 spermatozoa per mL, cooled to 4�C over 4 h, aspirated into 0.25-mL plastic straws (IMV Technologies, Aigle, France), frozen in a bio-freezer (IMV Technologies) in 3 steps from 4 to –140�C, and then plunged into liquid N2. Straws were thawed in a water bath at 37�C for 30 s. Sperm motility was analyzed microscopically immediately after collection, after dilution, and after 4, 24, 48, and 72 h of storage at 4�C. Post-thaw semen progressive motility was assessed microscopically, and sperm movement characteristics were analyzed by computer-assisted semen analysis (CASA) (SCA�, Microptic, Barcelona, Spain). Data were compared between extenders and bulls by 2-way ANOVA; percentages were transformed by arcsine transformation before ANOVA. Total and progressive sperm motility at 0 h after dilution ranged from 90 to 70% and was not different between extenders and bulls. There was no difference between bulls in total and progressive motility after 24 h of cold storage; however, both were significantly greater (P < 0.05) for Control (62.4 � 14.7 and 41.4 � 14.9) and E-1 (70.1 � 12 and 33.8 � 7.0) extenders than for the E-2 extender (22.5 � 17 and 1.2 � 1.3). Average post-thaw sperm motility was not different between bulls for either extender, but motility for Bioxcell (Control, 48.1 � 14.6%) and E-1 extenders (43.2 � 13.0%) were significantly greater (P < 0.05) than for E-2 extender (18.7 � 8.8%). There were no differences between bulls for all kinematic semen parameters: curvilinear (VCL), straight line (VSL), average path (VAP) velocities, linearity (LIN) and straightness (STR), evaluated by CASA before and after freezing; however, all were lower (P < 0.05) for the E-2 extender and not different between Control and E-1 extenders. Sperm movements derived from heads (VCL) and linearity of sperm(LIN), both closely related to field fertility, were in the range of 90.9 � 2.1 and 63.0 � 5.5 for E-3 (Control) extender; 99.1 � 3.4 and 49.4 � 3.5 for E-1; and 21.8 � 2.2 and 29.9 � 4.0 for E-2. In summary, zwitteronic soyabean lipid liposomes are an effective egg yolk substitute for the cryopreservation of Asturiana de la Monta�a bull semen; however, the homogenization protocol of the lipids-glycerol mixture must be improved.

24 EFFECT OF GnRH ON FIXED-TIMED ARTIFICIAL INSEMINATION PREGNANCY RATES OF WHITE-TAILED DEER

2010 ◽  
Vol 22 (1) ◽  
pp. 170
Author(s):  
J. Lambe ◽  
W. Forbes ◽  
B. M. Olcott ◽  
D. E. Sanders ◽  
R. A. Godke ◽  
...  
Keyword(s):  
Artificial Insemination ◽  
Pregnancy Rates ◽  
Transrectal Ultrasonography ◽  
Estrus Synchronization ◽  
Control Groups ◽  
Motile Cells ◽  
Timed Artificial Insemination ◽  
And Control ◽  
Uterine Body ◽  
Synchronization Protocol

During the fall 2008 breeding season in Louisiana, 2 synchronization protocols for fixed-timed artificial insemination (FTAI) in White-tailed deer were assessed. The objective was to determine if GnRH at FTAI improved pregnancy rates in White-tailed deer. White-tailed does (n = 35) with a mean body weight of 65.8 kg (range: 54.0 to 79.8 kg) and average age of 5.9 years (range: 1.5 to 9.5 years) were stratified by weight, age, and last fawning date into 2 groups. Treatment and control synchronization protocols were randomly assigned to each group. Does were synchronized with a CIDR-G device for 14 d and were then subjected to either FTAI 60 hpost-CIDR removal (control, n = 17) or 100 μg (i.m) injection of GnRH at FTAI 60 h post-CIDR removal (treated, n = 18). At insemination (AI), insemination pipette placement score (IP; 0 = at cervical os to 3 = within uterine body), mucous scores (clear/cloudy, viscous/nonviscous, or no secretions), vulva assessments (hyperemic/nonhyperemic and swollen/not swollen), and sperm progressive motility were recorded. Does were inseminated with frozen-thawed sperm (5 × 107 progressively motile cells pre-freeze) from 2 fertile bucks stratified across each treatment group. Starting 28 d following AI, intact bucks (ITB) were introduced into both groups for natural mating. Pregnancy was determined via transrectal ultrasonography 73 or 80 d postinsemination. Does, confirmed pregnant via ultrasonography, had fawns within the reported gestation range of 187 to 222 days. Placentomes were visualized and measured in AI pregnancies (range: 32.7 to 56.2 mm in length), whereas pregnancies derived from ITB presented no identifiable placentomes. However, crown-rump measurements were obtainable from ITB pregnancies (range: 13.4 to 21.7 mm). Five does were not included in the final analyses as they were either lost to predators or removed because of illness. IP (1.4 ± 0.24 v. 1.3 ± 0.30; P = 0.671), mucous classifications (3.0 ± 0.35 v. 2.5 ± 0.39; P = 0.311), vulva assessments (2.1 ± 0.29, 1.7 ± 0.23; P = 0.223), and sperm motility (1.6 ± 0.16, 1.7 ± 0.22; P = 0.829) were not different for pregnant and nonpregnant AI does, respectively. Treatment did not affect AI pregnancy rates (53 v. 27%) or fecundity rates (1.6 v. 1.3 offspring/doe) for the GnRH treated and control groups, respectively. Addition of GnRH to a 14-day estrus synchronization protocol did not result in significantly higher pregnancy rates compared with controls. More studies are needed to determine the effect of GnRH on White-tailed pregnancies following FTAI protocols. We have demonstrated that differentiating pregnancies derived from AI and ITB could be accomplished by utilizing transrectal ultrasonography as early as 73 d postinsemination in White-tailed does.

P–100 Metabolic, hormonal, and inflammatory status in sub-fertile men with obesity and diabetes

2021 ◽  
Vol 36 (Supplement_1) ◽  
Author(s):  
S Abbasihormozi ◽  
A Kouhkan ◽  
A Shahverdi ◽  
A Parhizkar ◽  
Z Zolfaghary ◽  
...  
Keyword(s):  
Semen Analysis ◽  
Metabolic Changes ◽  
Semen Parameters ◽  
Computer Assisted ◽  
Obesity And Diabetes ◽  
Hormonal Dysfunction ◽  
Hs Crp ◽  
Type 2 Diabetic

Abstract Study question To evaluate the association between sperm functionality parameters and biochemical, hormonal, and inflammatory indices in obese and diabetic men. Summary answer Metabolic changes,hormonal dysfunction,and the presence of inflammatory mediators might be considered possible mechanisms in the development of sub-fertility in obese and diabetic sub-fertile men What is known already Although the higher prevalence of subfertility in obese and diabetic men during the reproductive age is evident, the mechanisms by which obesity and diabetes mellitus (DM) cause male infertility are not entirely understood. Several pathways might be involved in the role of obesity in semen quality, thereby inducing alterations in hormonal profiles, abnormal lipid metabolism, and possibly the formation of inflammatory cytokines, ultimately leading to impaired sperm function Study design, size, duration We enrolled normal weight (BMI&lt;25 kg/m2) and non-type–2 diabetic (control=40), obese and non- type–2 diabetic (obese=40), non-obese and type–2 diabetic (Lean-DM=35), and obese and type–2 diabetic (Obese-DM=35) sub-fertile men, aged 20–50 years, referring to Royan infertility clinic (Tehran, Iran) from March to September 2014 Participants/materials, setting, methods After enrollment and receiving informed consent, all men underwent face-to-face private interviews. The obesity-associated markers, insulin resistance, beta-cell function, hormonal and lipid profile, inflammatory indices, and semen analysis were assessed in four experimental groups. Semen analysis was examined after 2–5 days of sexual analysis).abstinence based on WHO-recommended methods by CASA system (computer-assisted sperm Main results and the role of chance Main results and the role of chance: Our finding showed that diabetic markers were significantly increased in two diabetic groups, while obesity indices were markedly increased in two obese groups. Conventional sperm parameters were significantly lower in obese DM, lean DM, and obese groups compared with the control (p &lt; 0.05). Serum levels of total testosterone (TT) and sex hormone-binding globulin (SHBG) were significantly lower in men with obesity and DM compared with the control (p &lt; 0.05).There was a significant difference in the concentration of high-sensitivity C-reactive protein (hs-CRP) among four experimental groups. Moreover, serum leptin was significantly increased in obese DM, lean DM, and obese groups. Serum insulin levels had a positive correlation with metabolic-associated indices (WC, BMI, FBS,HbA1c,and HOMA-IR), as well as hs-CRP levels, whereas it had a negative correlation with count, motility, and morphology. There is also a negative association between metabolic-associated indices (WC, BMI, FBS, HbA1c, and HOMA-IR) and semen parameters. Limitations, reasons for caution It was better to evaluate inflammatory biomarkers be examined in other tissues Wider implications of the findings: The results of this study demonstrated the association of metabolic changes, hormonal dysfunction, and inflammatory responses with the semen parameters of sub-fertile men with obesity and diabete. Trial registration number Not applicable

86 MOTILITY AND VIABILITY OF BULL SEMEN DURING 24 HOURS OF STORAGE AT 4°C

2006 ◽  
Vol 18 (2) ◽  
pp. 151
Author(s):  
M. E. Carini ◽  
R. Cavia ◽  
G. Larraburu ◽  
G. M. Brogliatti
Keyword(s):  
Storage Time ◽  
Semen Analysis ◽  
Computer Assisted ◽  
Bull Semen ◽  
Multiple Comparison Test ◽  
Straight Line ◽  
Semen Extender ◽  
One Way Anova ◽  
Velocity Average ◽  
Lateral Head

Currently, cryopreservation process of fresh bull semen is carried out between 3 and 6 hours of refrigeration at 4°C post-collection (Hafez, 1989). However, it is sometimes difficult when the cryopreservation process is not available at the site of collection. The objective of this study was to determine seminal motility and viability in samples maintained at 4°C during 24 hours. A total of 98 ejaculates from 23 adult bulls (Angus, Brangus, Braford and Hereford) were collected and diluted in a semi-defined semen extender (Andromed, Minitüb, Tiefenbach, Germany) and stored at 4°C. Parameters of velocity average path (VAP, µm/s), velocity straight line (VSL, μm/s), amplitude lateral head (ALH, μm), linearity (LIN, %), percentage of rapid cells (RAPID, %), percentage of slow and static cells (SL/ST, %), and viability (VIA, %) were determined by Computer Assisted Semen Analysis (CASA, HTM-ceros 12.1, Berkeley, CA, USA). Measurements were done at 6, 9, 12, and 24 h. The obtained results were analyzed statistically with one-way ANOVA and Dunnet Multiple Comparison Test and are summarized in Table 1. There were no significant differences (P > 0.05) in the VAP, RAPID, or SL/ST during 24 h of storage at 4°C. Measurements were significantly different (P < 0.01) for VSL and VIA at 24 h. Measurements of ALH were increased from 12 h (P < 0.01) and consequently, LIN decreased at the same time (P < 0.01). These results suggest that there are no differences in velocity, except in VSL at the end of the storage time. The type of movement of the spermatozoa change, because ALH increases and the trajectory loses linearity. A decrease in viability suggests that from 24 h of storage, the membrane of the spermatozoa becomes more susceptible. More research needs to be done to evaluate the competence of this time-storage semen in the artificial insemination trial. Table 1. Parameters of motility and viability of semen maintained at 4°C during 24 h This research was supported by Centro Genético Bovino de EOLIA S.A.

137 Assessment of fertilizing ability of Merino ram semen cold stored up to 48h by heterologous IVF of bovine oocytes

2019 ◽  
Vol 31 (1) ◽  
pp. 194 ◽  
Author(s):  
D. A. Galarza ◽  
M. Ladrón de Guevara ◽  
P. Beltrán-Breña ◽  
M. J. Sánchez-Calabuig ◽  
A. López-Sebastián ◽  
...  
Keyword(s):  
Semen Analysis ◽  
Skim Milk ◽  
Semen Parameters ◽  
Computer Assisted ◽  
Cleavage Rate ◽  
Straight Line ◽  
Fertilizing Ability ◽  
Pronuclear Formation ◽  
Bovine Oocytes

The use of cold-stored ram semen has been applied in sheep AI programs, because it preserves its fertilizing ability similar to fresh. Besides, the heterologous IVF has been successfully employed to assess semen fertilizing ability in several species. Hence, we aimed to evaluate the fertilizing ability of ram semen cold stored up to 48h at 5°C by assessing heterologous IVF using bovine oocytes. Fifteen pools of 3 normospermic Merino ram (2-7 years) ejaculates were collected using artificial vagina, diluted to 200×106 spermatozoa mL−1 with ultra-heat-treatment-based extender (skim milk-6% egg yolk) and cold stored up to 48h. In vitro matured zona-intact bovine oocytes were subjected to heterologous IVF using fresh semen (FS, n=707), semen cold stored to 24h (CS24, n=832) or semen cold stored to 48h (CS48, n=611). In parallel, homologous IVF (control, n=1356) and parthenogenesis (parth control non-fertilized oocytes, n=334) were performed. Ram non-selected and selected (BoviPure, Nidacon International, Mölndal, Sweden) semen parameters were evaluated by computer-assisted semen analysis. Sperm-oocyte interaction was assessed at 2.5h post-insemination (hpi) by evaluating the number of bound spermatozoa, whereas penetration and polyspermy were evaluated after 12 hpi. Presumptive zygotes were fixed and stained with Hoechst 33342 at 18, 20, 22, 24 and 26 hpi to assess pronuclear formation using phase contrast and confocal microscopy. Cleavage rate was evaluated in all groups at 48 hpi. Data obtained from 5 replicates were analysed using one-way ANOVA. Data was expressed as mean±standard error of the mean. In terms of sperm storage time, non-selected semen showed a significant decrease (P&lt;0.05) for CS24 and CS48 compared with FS on progressive motility [SPM (%): 52.30±4.1 and 36.9±5.5v. 71.3±1.6] and straight-line velocity (mm s−1: 132.2±6.1 and 109.7±6.3v. 176.7±4.3), respectively. However, selected semen showed a decrease (P&lt;0.05) only for CS48 when compared with CS24 or FS on SPM (35.6±3.9v. 56.1±6.91 and 59.3±2.6) and straight-line velocity (83.5±4.4v. 105.3±6.5 and 110±2.0), respectively. No differences were observed between heterologous IVF groups in all parameters evaluated. Homologous IVF showed a higher percentage of penetration only when compared with heterologous FS group (44.4±6.8v.12.5±4.5%; P&lt;0.01). The polyspermy was higher in heterologous CS24 group when compared with homologous IVF (11.4±3.4v. 3.8±2.2; P&lt;0.05). The homologous IVF group, as expected, showed the higher percentage of pronuclear formation at 18 hpi compared with heterologous IVF with FS (67.3±5.8v. 35.2±5.6%), CS24 (72.1±4.5 v. 37.2±5.7%) and CS48 (63.0±6.0 v. 27.0±5.6%), respectively (P&lt;0.001). Likewise, cleavage rate was higher in homologous group compared with heterologous IVF and parthenogenetic groups for FS (78.3±2.6.8v. 46.3±3.2 and 7.0±2.3%), CS24 (78.4±2.6 v. 48.3±3.2 and 4.9±2.0%), and CS48 (78.4±3.3 v. 43.3±3.5 and 4.3±1.2%), respectively (P&lt;0.001). In conclusion, Merino ram semen cold stored up to 48h maintains its fertilization ability to the same extend as fresh and can be used for sheep crossbreeding programs.

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