The possibility of obtaining intergeneric hybrids via White Kołuda (Anser anser L.) goose insemination with fresh and frozen-thawed Canada goose (Branta canadensis L.) gander semen

The objective of the present experiments was to produce the intergeneric hybrids of domesticated and wild goose via artificial insemination with fresh and frozen-thawed semen. The experiments were carried out during two successive goose reproductive seasons, on eight five-year-old Canada Goose (Branta canadensis L.) males used as semen donors and 16 two-year-old White Ko?uda geese designated to fertility tests. Pooled semen was collected twice a week by the dorso-abdominal massage. In freshly collected semen, ejaculate volume, color, consistency, degree of fecal or blood contamination, spermatozoa concentration, motility, and morphology were evaluated. Part of the semen collected in the first year of the experiment (Experiment 1) was used for geese insemination with fresh semen, while the remainder was frozen. In Experiment 2 all samples were subjected exclusively to freezing procedure. Geese were inseminated once a week with fresh semen in a dose of 80 μl or 160 μl, and twice a week with frozen-thawed semen in a dose of 80 μl (160 μl per wk) or 100 μl (200 μl per wk). Eggs were set weekly and incubated up to hatching.The volume of ejaculates varied from 0.100 to 0.470 ml; spermatozoa concentration from 140 to 310 million ml⁻¹; progressive movement was observed in 40 to 60% of spermatozoa; the percentage of total live spermatozoa ranged from 69.3 to 92.0%, the highest percentage (34.0-68.3) was represented by live normal spermatozoa and those with bulb-head (13.3-41.0). Cryopreservation caused a decrease in percentage of motile cells to 30%; total live spermatozoa contribution by 27.2%p, including those live normal by 15.9%p (in relation to the fresh semen), bulb-head spermatozoa by 10.9%p, and increase (by 5.9%p) in number of spermatozoa with other deformations. Goose insemination 1×/week with fresh semen containing about 10.3 million live normal spermatozoa resulted in 66.7% of fertile eggs and with dose higher by 2.8 million spermatozoa (on average) the fertility increased by 20.9%p (up to 87.6% on average). Hatchability from set and fertile eggs was 55.9% and 83.9% vs. 66.3% and 75.6%, respectively. After twice a week insemination with frozen-thawed semen containing about 10.2 million live normal cells 58.2% eggs were fertile; hatchability from set eggs was 42.8% and from fertile eggs 71.7%, while insemination dose increase by 2.7 million spermatozoa per week caused a fertilization increase by 3.8%p (62.0% on average), this increase was not statistically significant, but hatchability from the fertile eggs (95.4%), was significantly (P < 0.05) higher.The use of AI with fresh semen in the creation of intergeneric hybrids of Canada goose males and White Ko?uda females allows a high level of egg fertility to be obtained. Furthermore, one limitation which is the short reproductive season of the Canada goose may be overcome by the use of cryopreserved semen.     

Development of an artificial insemination protocol in llamas using cooled semen

The objective of this study was to design an AI protocol using cooled semen to obtain pregnancies in the llama. Each raw ejaculate was subdivided into four aliquots which were extended 1:1 with: (1) 11% lactose-egg yolk (L-EY), (2) Tris-citrate-fructose-egg yolk (T-F-EY), (3) PBS-llama serum (S-PBS) and (4) skim milk-glucose (K). Each sample reached 5°C in 2.5 h and remained at that temperature during 24 h. Percentages of the semen variables (motility, live spermatozoa) in ejaculates and samples cooled with L-EY were significantly greater than those obtained when cooling with the other extenders; therefore this extender was used (1:1) for all inseminations. Females were randomly divided into four groups (A-D) according to insemination protocol. Group A: females were inseminated with a fixed dose of 12 × 10(6) live spermatozoa kept at 37°C. Group B: females were inseminated with a fixed dose of 12 × 10(6) live spermatozoa, cooled to 5°C and kept for 24 h. Group C: females were inseminated with the whole ejaculate (variable doses), cooled to 5°C and kept for 24 h. These groups (A-C) were inseminated between 22 and 24 h after induction of ovulation. Group D: females were inseminated with the whole ejaculate (variable doses), cooled to 5°C, kept for 24 h and AI was carried out within 2 h after ovulation. Pregnancy rates were 75%, 0%, 0% and 23% for groups A, B, C and D respectively. These results indicate that it is possible to obtain llama pregnancies with AI using cooled semen and that the success of the technique would depend on the proximity to ovulation.     

Successful preservation of capercaillie (Tetrao urogallus L.) semen in liquid and frozen states

Experiments on semen collection and preservation were undertaken by Wroc?aw University of Environmental and Life Sciences and Forestry Wis?a, Poland to assist in the protection of the capercaillie (Tetrao urogallus L.) and to create an ex situ in vitro cryobank. Semen was collected from 11 captive-bred males, using dorsoabdominal massage. Ejaculates once obtained were diluted 3-fold at room temperature with EK diluent and then a number of them were stored at 4 °C for 18, 24, and 48 hours, while the remaining ejaculates were equilibrated with 6% dimethylacetamide and frozen by pipetting, drop-by-drop directly onto a liquid nitrogen surface. Frozen pellets were thawed at 60 °C in a water bath after 4 to 28 mo of storage. In total, 103 individually collected ejaculates (54 stored as liquid and 49 frozen in liquid nitrogen) were of appropriate value for further processing. The volume of ejaculates varied from 30 to 240 μL; spermatozoa concentration from 70 × 10⁶ mL⁻¹ to 1950 × 10⁶ mL⁻¹. The total amount of live spermatozoa in the fresh semen varied from 85.3% to 99.0%, of which from 41.1% to 85.3% were morphologically normal. Among morphologically abnormal forms, bulb-head (5.6% to 36.0%) and midpiece deformations (1.3% to 16.6%) were the most frequent. Dilution and semen storage up to 24 h at 4 °C did not affect the semen quality, as far as motility and sperm morphology are concerned. A significant (P < 0.05) decrease in total live (94.9 vs. 91.7%) and live normal cells (66.4 vs. 56.7%) was observed after 48 h. About 30% to 40% of spermatozoa remained motile. Cryopreservation significantly decreased (P < 0.05) the total number of live and live normal spermatozoa however, in relation to the fresh semen, their average content was 44.1% and 37.4%, respectively. Significant (P < 0.05) individual differences were observed in the quality of the fresh, liquid stored and the frozen-thawed semen assessed in terms of spermatozoa motility and morphology. After a single insemination with thawed semen containing 9.7 million live normal cells, 80% fertility and 100% hatchability were achieved. The obtained results indicate for the first time that there is the potential to use liquid stored and cryopreserved capercaillie semen to support conservation measures for the maintenance of genetic diversity, as well as to increase the number of reintroduced progeny of this endangered grouse species.     

Comparison of conventional and computer-assisted semen analysis in cockatiels (Nymphicus hollandicus) and evaluation of different insemination dosages for artificial insemination

Many psittacine species are threatened in the wild and also rare in captivity. Therefore, successful conservation and breeding programs are important to save these species. Unfortunately, clutches in conservation programs are frequently infertile. Semen evaluation is beneficial to investigate the causes of infertility and is advisable before artificial insemination (AI). In this study, we analyzed the semen of cockatiels (Nymphicus hollandicus) using two different methods and investigated different insemination dosages for AI. Cockatiels (n = 30) were divided into two groups (group A: nine males; group B: six males). The males in group B were endoscopically sterilized, whereas the males in group A were used as semen donors. In the first part of the study, the semen of males in group A was evaluated by semen analysis. Semen samples were collected by the massage technique and examined using a conventional light microscope and a computer-assisted semen analyzer for comparison. Results demonstrated that the evaluations of motility, progressive motility, and sperm concentration, but not of live/dead ratio, correlated strongly for both methods. However, the results for sperm concentration, progressive motility, and live/dead ratio differed significantly. In the second part of our study, the volume and quantity of spermatozoa of the semen samples were adjusted and used for AI of females of group B. Intravaginal insemination with 250,000 spermatozoa resulted in five of 17 (29%) eggs fertilized; however, intracloacal insemination resulted in only four of 57 (7%) eggs fertilized at 232,000 and 250,000 spermatozoa but none at higher or lower dosages.     

Flow cytometric evaluation of sperm apoptosis in semen of silver foxes in the breeding period

The objective of the study was to evaluate cytometrically the percentage of apoptotic and necrotic spermatozoa in fresh semen of silver foxes in the breeding season. In males F3 and F4 with high percentages of early apoptotic (A+Pi−), late apoptotic (A+Pi+) and necrotic (A−Pi+) spermatozoa as well as 56–65% of living spermatozoa (A−Pi−) with progressive motility, the semen was characterised by reduced fertility. In males F1 and F2 with spermatozoa showing the motility and viability of 89–90% and high percentages of living cells that do not bind Annexin V and propidium iodide, the semen was assessed as valuable and useful for artificial insemination. Amongst 16 females of group I and II inseminated with semen from F1 and F2 males, 15 (93.75%) had multi-cub litters – on average 6.1 and 4.8, respectively. In contrast, amongst 16 females of group III and IV inseminated with semen from F3 and F4 males, only 10 (62.5%) had litters with few cubs (on average 2.6 in group III and 2.1 in group IV). Our findings explicitly indicate that semen of farm male foxes should be evaluated before the breeding season, as one of the causes of reproduction failures is likely to be a high percentage of apoptotic and necrotic spermatozoa. Thanks to flow cytometry, fresh ejaculates can be speedily evaluated and their usefulness for artificial insemination determined.     

Elimination of apoptotic spermatozoa from rabbit insemination dose using annexin V associated with the MACS technique. A preliminary study

The aim of this study was to verify whether the separation and elimination of the apoptotic fraction in rabbit semen using a MACS technique may improve sperm fertility potential and consequently rabbit kindling rate. Semen samples from 25 New Zealand White (NZW) rabbit males were collected using an artificial vagina and evaluated using the CASA system for concentration and motility. For artificial insemination the best 11 bucks were chosen based on motility parameters. Their ejaculates were mixed to make a heterospermic pool and routinely diluted in a commercial insemination diluent (MiniTüb, Tiefenbach, Germany) at a ratio of 1:6. Diluted heterospermic spermatozoa were filtered through a Sartorius filter to wash out seminal plasma, re-diluted in binding buffer (Annexin V Microbead Kit, Miltenyi Biotec, Germany) at a ratio of 1:3.66 and divided into two groups: an experimental group intended for MACS separation and control group without MACS separation. Then hormonally treated females of NZW rabbits were inseminated with fresh doses of filtered heterospermic semen (n = 27; 0.5 ml I.D. per female) and MACS separated semen (n=28; 0.5 ml I.D. per female). Separation and subsequent elimination of apoptotic spermatozoa (positive selection) from the insemination dose (after negative MACS selection) was verified under in vivo conditions on the basis of increased kindling rate in the experimental group in comparison with kindling rate in the control group (81.3% vs. 73.8%). In conclusion, elimination of apoptotic spermatozoa by the use of the MACS technique results in a slight improvement in kindling rate of rabbit does.     

Estimation of genetic parameters of semen characteristics and reproductive traits in AI boars

(Co)variance components and further genetic parameters of boar semen characteristics and reproductive traits were estimated using the REML procedure applied to multi-trait animal models. The calculations were based on data from 210,733 ejaculates stemming from 2862 AI boars and collected from 1990 to 1997 in insemination stations for boars in the Czech Republic. Equal model equations for all traits included the AI station and the breed or breed combination as fixed effects, the interval between two collections for the boar as covariable and the animal and residual effects as random effects. The following heritabilities were estimated: semen volume 0.58, sperm concentration 0.49, progressive motion of spermatozoa 0.38, abnormal spermatozoa 0.34, number of total spermatozoa 0.42, number of insemination doses 0.40, number of piglets born alive 0.08, total number of piglets born 0.05 and conception rate 0.29. Heritabilities and genetic correlations were estimated on average values for each boar.     

Simple and Effective Methods of Freezing Capercaillie (Tetrao urogallus L.) Semen

A continuous decline in the number and range of capercaillie (Tetrao urogallus L.) in many European countries can be observed, mostly due to habitat destruction by human activity, unecological forestry management, and increased density of natural predators. Ex situ in vitro gene banks provide a unique opportunity to preserve the genetic material for future generations. Simple and effective cryopreservation methods for capercaillie semen are discussed. Semen was collected from seven males kept in the Capercaillie Breeding Centre at Forestry Wisła in Poland. Within five minutes after collection, ejaculates were diluted with EK diluent, then divided into two parts, and subjected to two freezing procedures: in pellets and in straws. In fresh semen, ejaculate clearness, viscosity, color and volume, as well as sperm concentration, motility and morphology, were evaluated, while in frozen-thawed semen only motility and morphology of sperm were determined. Fertilizing ability of thawed semen was examined for samples frozen in straws. Significant (P<0.05) differences between individual males were found in relation to the majority of fresh semen traits: ejaculate volume averaged 102.1 µL (varying from 49.0 to 205.0); average sperm concentration was 632.5 x10⁶ mL^-1 (178.8–1257.1); percentage of live normal cells varied from 39.2 to 70.3% (58.7% on an average); percentage of motile cells ranged from 76.0 to 85.7%) and motility parameters were male dependent, as well. Both cryopreservation methods had a negative effect on morphology and motility of frozen-thawed semen; however, the straw method yielded 60.7% and the pellet method 42.5% of live cells in total in thawed semen (P<0.05), while the number of live normal (intact) cells was similar (22.4 and 22.2%, respectively). Egg fertility varied between 77.8 and 91.7% (average 84.4%). Both freezing procedures seem to be effective in obtaining acceptable viability and high fertilizing potency of thawed sperm and can be used to create a gene bank of capercaillie semen.     

The effect of DMA level on morphology and fertilising ability of Japanese quail (Coturnix japonica) spermatozoa

The effect of different levels (2, 4 or 6%) of DMA (dimethylacetamide) on the morphology and fertilising ability of unfrozen quail spermatozoa was evaluated. Semen was collected from 72 males kept individually in cages and randomly divided into four groups: Group I--control -- fresh undiluted semen (12 males) and three experimental groups (20 males each) - semen diluted 1:1 with Lake's extender and supplemented with 2% (Group II), 4% (Group III) or 6% (Group IV) of DMA (final concentration). Sperm morphology was evaluated at each step of semen preparation, i.e. in fresh and diluted semen, semen supplemented with DMA and semen that remained after insemination. For fertility tests, 36 females were divided into four groups (nine females each). Females in the control group were inseminated with 10 microl of fresh semen, in the experimental groups with 40 microl of diluted semen. Each stage of quail semen treatment had a deleterious effect on sperm morphology. The highest percentage of morphologically normal cells in semen evaluated after insemination, was observed in samples with 2% DMA, and the lowest--in samples with 6% DMA. Semen dilution and DMA addition significantly affected the fertilising potency of spermatozoa. Fertility of eggs collected from the control group (71.5% on average) was significantly higher (P相似文献   

An effective method for freezing White Italian gander semen

Efficiency of freezing method, worked out for the White Italian gander semen was evaluated by comparing motility, morphology and fertilizing ability of spermatozoa in fresh and frozen-thawed semen. A part of pooled semen, collected from 25 White Italian ganders by dorso-abdominal massage was used immediately for artificial insemination of 10 geese (the control group) with a dose of 80 microl. This insemination was performed six times at weekly intervals. The remainder of the semen was diluted 1:0.5 (v/v) with EK diluent, equilibrated for 15 min at +4 degrees C, mixed with 6% (v/v) of dimethylformamide (DMF) and frozen to -140 degrees C at a rate of 60 degrees C/min. Frozen semen was thawed in a 60 degrees C water-bath and inseminated twice weekly in a dose of 100 microl (10 females of the experimental group, 12 inseminations were made). The freezing process affected spermatozoa motility and morphology, but had no effect on their fertilizing ability. Positive movement was observed in 50-60% of the spermatozoa in fresh semen and about 40% of the frozen-thawed cells. The average percentage of total live and live normal spermatozoa decreased due to freezing from 92.2 to 68.4% and from 34.7 to 14.1%, respectively. After the fresh semen insemination with average 12 million of the live normal spermatozoa per week average fertility was 88.24%; hatchability of set eggs was 80.88% and hatchability of fertile eggs was 91.67%. For frozen-thawed semen inseminated with average 9.5 million of the undamaged spermatozoa per week, the average fertility and hatchability rate was 83.78, 73.87, and 88.17%, respectively. Fecundity rates obtained after insemination with the frozen-thawed gander semen allow for the application of the freezing technique into breeding practice, in place of natural mating or to assist natural mating in periods of lowered fertility level.     

The dependence of the growth rate and meat content of young boars on semen parameters and conception rate

Boars have a decisive impact on the progress in pig production, however, there is no recent information about the optimal growth parameters during the rearing period for modern breed later used in artificial insemination (AI) stations. Therefore, the objective of the research was to conduct semen parameter and conception rate analyses on the basis of growth rate and meat content assessments made during the rearing of AI boars of different genotypes. The study was carried out between 2010 and 2014 and included 184 boars in five breed combinations: 46 Polish Large White, 50 Polish Landrace, 27 Pietrain, 36 Duroc×Pietrain and 25 Hampshire×Pietrain. Boars were qualified by daily gains and meat content assessment (between 170 and 210 days of life). A total number of 38 272 ejaculates were examined (semen volume (ml), spermatozoa concentration (×10⁶ ml⁻¹), total number of spermatozoa (×10⁹) and number of insemination doses from one ejaculate (n)). The fertility was determined by the conception rate (%). Semen volume, spermatozoa concentration and conception rate (P<0.01), followed by the total number of spermatozoa and insemination doses (P<0.05) were characterized by the highest variability in relation to breed of boars. The effect of daily gains was reported for spermatozoa concentration, number of insemination doses, conception rate (all P<0.01) and total number of spermatozoa (P<0.05). The peak of growth for spermatozoa concentration, total number of spermatozoa, insemination doses and conception rate was achieved for 800 to 850 g gains. Meat content affected semen volume, number of insemination doses and conception rate (P<0.05). Rearing boars while maintaining daily gains at the 800 to 850 g level and 62.5% to 65% meat content helps AI stations to increase the efficiency and economic profitability, and the number of insemination doses to increase by up to 300 doses/boar within a year. The analyses of growth parameters may help increase the efficiency and economic viability of AI stations.     

Conception rates following intrauterine insemination of European (Dama dama dama) fallow deer does with fresh or frozen-thawed Mesopotamian (Dama dama mesopotamica) fallow deer spermatoza

A total of 121 European fallow deer does, being either parous ( n = 15) or nulliparous ( n = 106), were treated with intravaginal progesterone impregnated controlled internal drug release (CIDR) devices for 14 days. The does were divided into three treatment groups and inseminated in utero by laparoscopy, at approximately 65 hours after CIDR device removal, with 25 × 10⁶ fresh Mesopotamian ( n = 40), 25–35 × 10⁶ frozen-thawed Mesopotamian ( n = 41) or 30–32.5 × 10⁶ frozen-thawed European ( n = 40) fallow deer spermatozoa. The semen used had been collected, from two Mesopotamian and two European fallow deer bucks, by electroejaculation under general anaesthesia. Pregnancy was diagnosed by rectal ultrasonogrdphy on Day 50 after insemination.
There were no apparent differences in the quality of ejaculates between the two subspecies of fallow deer. The volume of semen and the total number of spermatozoa ranged between 0.6–1.2 ml and 2.11–4.95 × 10⁹ per ml of semen, respectively. Evaluation of frozen-thawed spermatozoa revealed post-thaw motility rates between 50–70%. The overall conception rate was 65.3%. A higher conception rate was observed following insemination with European than Mesopotamian frozen-thawed spermatozoa (75% vs. 53.7%, respectively, P < 0.05). Insemination with fresh Mesopotamian spermatozoa increased the conception rate to a level not significantly different from that observed following insemination with European frozen-thawed spermatozoa (67.5% vs. 75%, for fresh Mesopotamian and frozen-thawed European semen, respectively).     

Preliminary studies on cryopreservation of hare (Lepus europaeus Pallas, 1778) semen

In the last decades, a significant decrease in hare population has been observed; for this reason, the aim of the study was to check if hare semen could be preserved in liquid nitrogen, with an extender used for rabbit semen. The results should provide a basis for creating a gene bank of the species. Ten ejaculates (volume above 0.4 ml, percentage of motile spermatozoa above 75%, spermatozoa concentration above 250 x 10(6) ml), obtained with electroejaculation method from four males, were frozen in an extender of the following composition: Tris (3.028 g), citric acid (1.675 g), glucose (1.25 g), dimethylsulphoxide (DMSO) (4.5%, v/v), egg yolk (17%, v/v) and distilled water to 100.00 ml. The motility of post-thawing spermatozoa was 40.50+/-7.97%, percentage of spermatozoa with normal acrosomes 76.10+/-3.69% and percentage of live spermatozoa 35.05+/-4.21%. Based on the properties of freezing-thawing semen, the hare semen can be successfully preserved in extender used for rabbit semen.     

The importance of porcine sperm parameters on fertility in vivo

It would be desirable to use semen parameters to predict the in vivo fertilizing capacity of a particular ejaculate. In animal production, an ejaculate is divided into multiple doses for artificial insemination (AI); therefore, it would be economically beneficial to know the functional quality (i.e., fertility) of the semen before it is inseminated. To identify a predictive assay of the fertilizing capacity of a porcine ejaculate, we performed 4 rapid assays of sperm quality (motility, viability, physiological status as assessed by chlortetracycline fluorescence, and ATP content) on samples from 9 ejaculates, before and after a thermal stress test (42.5 degrees C, 45 min). These parameters were subsequently correlated with in vivo fertility resulting from AI with 2 sperm doses, 3 x 10(9) or 0.3 x 10(9) motile cells in 70 mL (optimal or suboptimal sperm number per insemination, respectively) from these same ejaculates. No parameter was correlated to the fertility rates obtained after inseminating with the optimal semen doses, either before or after the thermal stress test (P > 0.05). However, with respect to the animals inseminated with the suboptimal semen dose, sperm motility (the percentage of motile spermatozoa as assessed visually by microscopy) prior to thermal stress was well-correlated to fertility rates (r = 0.783, P = 0.01). The percentage of spermatozoa displaying the chlortetracycline Pattern AR (acrosome reaction) was also statistically related to fertility (r = 0.05, P = 0.04), but the biological importance of this relationship is questionable given the small variation among ejaculates (range: 0 to 2%). No other sperm parameter was significantly related to fertility rates in this group (P > 0.05). These data, therefore, indicate that sperm motility is a useful indicator of sperm fertilizing capacity in vivo. Moreover, to identify a predictor of semen fertility it is critical that the number of spermatozoa used during insemination is sufficiently low to detect differences in sperm fertilizing efficiency.     

French field results (1985-2005) on factors affecting fertility of frozen stallion semen

Results on procedures for freezing stallion semen and the subsequent fertility during 20 years are presented. The present system applied in French National Stud includes: (1) a freezing protocol (dilution in milk, centrifugation and addition of freezing extender (INRA82+egg yolk (2%, v/v)+glycerol (2.5%, v/v) at 22 degrees C, a moderate cooling rate to 4 degrees C and freezing at -60 degrees C/min in 0.5-ml straws); (2) selection of ejaculates showing post-thaw rapid motility >35%; and (3) an insemination protocol (mares examined once daily, two AI of 400 x 10(6) spermatozoa 24 h apart before ovulation, sufficient number of straws to have the possibility to perform six AI of 400 x 10(6) total spermatozoa, i.e. 2.4 x 10(9) total spermatozoa available per mare per season). This system was applied to >110 stallions per year, the average post-thaw motility of ejaculates was 50% (>1800 ejaculates) before selection. The semen freezability was defined as the number of selected ejaculates divided by the total number of ejaculates frozen. Of the stallions, 5, 4, 5, 21 and 64% had semen freezability of 0-10, 10-33, 33-60, 60-90 and over 90%, respectively. Per-cycle pregnancy rate was 45-48% (>1500 mares per year, 1.8 cycles per mare) and foaling rate 64%. In comparison, per-cycle pregnancy rate and foaling rate of mares hand-mated to stallions were 57-59% and 64%, respectively. The average number of straws used was 32-35 (1.75 x 10(9) total spermatozoa) per mare per season. According to our results and the literature, the most important factors for improving fertility of frozen equine semen include: (1) a low concentration of glycerol (2-3.5% final concentration); (2) a suitable base extender for freezing like Lactose-Glucose EDTA or INRA82; (3) a post-thaw motility >30-35%; and (4) a sufficient number of spermatozoa per mare per season (1.5-2 x 10(9) total spermatozoa for two to three cycles) divided into small units. Numbers of spermatozoa, lower than 750.10(6) total spermatozoa per cycle, could result in lower per-cycle pregnancy rate with higher additional costs for management of mares. Because there are no particular regulations on quality and quantity of equine semen in the European Community, there is a need for the uniformity of information about frozen semen. A codification is suggested, based on the number of spermatozoa available per mare per season, the post-thaw motility and the final glycerol concentration.     

Sources of spermatozoa loss during collection and artificial insemination of horses

During artificial insemination of horses, it is important to accurately estimate the number of spermatozoa in each insemination dose. However, little research exists regarding sources of spermatozoa loss during collection and artificial insemination. Therefore, spermatozoal losses were quantified in the dismount loss (187.6×10(6)±62.5×10(6)spermatozoa), gel fraction (179.8×10(6)±61.7×10(6)spermatozoa), and the collection receptacle (136.1×10(6)±26.9×10(6)spermatozoa). Spermatozoal losses were examined in the centrifuge tube (25.8×10(6)±2.1×10(6)spermatozoa), AI pipette during the air removal (90.9×10(6)±8.5×10(6)spermatozoa), and spermatozoa remaining in the AI pipette after insemination (342.9×10(6)±21.4×10(6)spermatozoa). The average cumulative loss was 14.2±2.9% of the total spermatozoa ejaculated with approximately half of the loss due to the process of semen collection and half due to the process of artificial insemination. Spermatozoa retained in the AI pipette, after insemination with extended semen, represented the greatest source of loss.     

Effects of dead spermatozoa on motion characteristics and membrane integrity of live spermatozoa in fresh and cooled-stored equine semen

The aim of this study was to determine if dead spermatozoa reduced motility or membrane integrity of live spermatozoa in fresh and cooled-stored equine semen. Three ejaculates from each of three stallions were centrifuged and virtually all seminal plasma was removed. Spermatozoa were resuspended to 25 x 10(6) spermatozoa/ml with EZ-Mixin CST extender and 10% autologous seminal plasma, then divided into aliquots to which 0 (control), 10, 25, 50, or 75% (v/v) dead spermatozoa were added. Dead spermatozoa preparations contained 25 x 10(6) spermatozoa/ml and 10% seminal plasma from pooled ejaculates of the three stallions, in EZ-Mixin CST extender. Spermatozoa were killed in the pooled ejaculates by repeated freezing and thawing, then stored at -20 degrees C until warmed to 37 degrees C and mixed with aliquots of fresh spermatozoa to be cooled and stored in an Equitainer for 24h. Motion characteristics (% total motility (MOT), % progressive motility (PMOT), and mean curvilinear velocity (VCL)) for fresh and 24h cooled samples were determined using a computerized spermatozoal motion analyzer. The presence of up to 75% dead spermatozoa did not adversely affect MOT or PMOT of live spermatozoa in either fresh or cooled-stored semen. However, VCL and the percentage of membrane-intact spermatozoa were reduced compared to control samples when 75% (v/v) dead spermatozoa were added. Membrane integrity, as assessed by staining with carboxyfluoresein diacetate-propidium iodide, was highly correlated (r>0.8; P<0.001) with MOT and PMOT in both fresh and cooled-stored semen samples. Results of this study have application to the processing of both cooled and frozen equine semen.     

Proportion of males with lower fertility spermatozoa estimated from heterospermic insemination

This study was designed to evaluate the proportion of males with spermatozoa detectably less fertile than the spermatozoa from other males. Previously unpublished and published data from heterospermic trials involving insemination with equal numbers of spermatozoa and resulting in at least 11 offspring from each pair of males were analyzed. The proportion of pairs in which the males sired equivalent numbers of offspring were 0.42, 0.18, 0.33 and 0.09 for trials with fresh boar semen, liquid-stored boar semen, frozen bull semen and fresh rabbit semen, respectively. The calculated proportion of males with less fertile spermatozoa were 0.36, 0.57, 0.42 and 0.70, respectively. Although these differences in fertility would not be apparent in some management systems, a high proportion of ejaculates had spermatozoa that were detectably less fertile.     

Sperm morphology is better in the second ejaculate than in the first in domestic cats electroejaculated twice during the same period of anesthesia

Several species produce ejaculates of inferior quality after a period of sexual abstinence, but the frequency of semen collection has thus far not been shown to affect sperm morphology in felids. The aim of this study was to determine whether sperm morphology and motility would differ between 2 ejaculates collected from the same cat within a short interval. Fifteen male domestic cats were anesthetized and then electroejaculated twice, with a 5- to 10-min interval between treatments. A standardized electroejaculation regimen was used with 80 stimuli, from 2 to 5 V, for each ejaculate. The first ejaculates contained significantly higher (P < 0.05) proportions of distal droplets, coiled tails and immotile spermatozoa than the second ejaculates, which contained significantly higher proportions of morphologically normal spermatozoa (40.9 vs 54.6%) but a lower sperm count (39.0 x 10(6) vs 5.2 x 10(6)). The higher proportions of defective spermatozoa and the lower motility in the first ejaculate than in the second were probably due to the aging of spermatozoa in the epididymis. These results show that the second ejaculate collected within a short interval has better sperm morphology and motility than the first and that this should be considered when evaluating semen quality in the domestic cat and when collecting cat semen to be used for artificial insemination or to be frozen for storage.     

Deep intra-uterine artificial inseminations using cryopreserved spermatozoa in beluga (Delphinapterus leucas)

Artificial insemination (AI) with liquid-stored spermatozoa and sperm cryopreservation using directional freezing (DF) have been successful in the beluga. This study built on this foundation to develop a deep intra-uterine AI technique with frozen-thawed semen in beluga. Forty-two ejaculates from one male were cryopreserved using DF technology and subsequently used for 10 insemination attempts with seven females. Percentage pre- and post-thaw progressive motility and viability were (mean ± SD) 73.0 ± 12.2, 38.4 ± 8.8, 88.0 ± 0.1, and 59.3 ± 15.7%, respectively. A series of GnRH injections (3 x 250 μg, IV, 1.5 to 2 h apart) were used to induce ovulation, once a growing follicle >2.5 cm in diameter was visualized via trans-abdominal ultrasonography. Artificial insemination was performed at 30.1 ± 3.8 h post-initial GnRH injection with semen deposited in the uterine horn, 92.6 ± 16.2 cm beyond the genital opening using a flexible endoscope. The external cervical os (cEOS) was located beyond a series of 5 to 10 vaginal rings, 44.8 ± 9.3 cm from the external genital opening. The internal bifurcation of the uterus was 27 ± 6.8 cm beyond the cEOS. Ovulation occurred at 8.5 ± 7.6 h post-AI. Two of 10 inseminations (20%) resulted in pregnancy. The first pregnancy resulted in twins; both calves were born 442 d after AI, with one surviving. The second pregnancy is ongoing. These findings represent the first successful application of AI using frozen-thawed semen in beluga, and are important examples of how assisted reproductive technologies can provide tools for the global management of threatened species.