Academic literature on the topic 'Sheep Sheep Artificial insemination. Semen'

Sperm-sexing technology using flow cytometry is in advanced stages of development for the sperm of several species. The sorting process could compromise sperm viability and sperm require specific handling procedures both before and after sorting to maintain the integrity and function of the sorted sperm. Standard freezing protocols have been modified for post-sorting cryopreservation of sperm and frozen sperm have been successfully thawed, sorted, refrozen and subsequently used to produce offspring. The relatively low numbers of available sorted sperm have, in some cases, led to modification of artificial insemination techniques to maximise efficiency of use. Multiple ovulation and embryo transfer, or in vitro fertilisation and associated technology, may lead to the more efficient use of sexed sperm.

The complex anatomical structure of the ewe reproductive tract accompanied with low quality of frozen ram semen for artificial insemination, resulted in a challenge with regard to using superior genotypes for reproductive ovine performance. Hence, improved genetics in ovine management has not been efficiently and widely used especially in undeveloped countries. Therefore, intrauterine semen deposition by laparoscopic insemination should be adopted in the current sheep production systems. Thus, this study aimed to assess the pregnancy rate and lambing rate of ewe inseminated by laparoscopic insemination techniques using frozen-thawed semen. The research used imported frozen semen from two rams of the Lacaune breed. Ewes were grouped according to age in years (1, 2 and 4). Before insemination, the semen was examined microscopically for its motility and viability and thereafter the laparoscopic artificial insemination technique was performed to 19 Lacaune breed ewes using frozen-thawed semen. The overall pregnancy and prolificacy rates were 31.57% and 42.10% respectively. Out of 2 ewes in the 1-year age group that were inseminated, only 1 ewe lambed representing 50%. However, from 16 ewes inseminated of four-year age group, 5 ewes lambed representing 31.25%. Significant difference based on age group was not evaluated due disproportionate of the data, (such that the data included 2 ewes in one-year-old age, 1 ewe in 2-year-old age and 16 ewes in 4-year-old age). Based on the ram semen, 33.33% and 30% of the inseminated ewes were pregnant from ram A and ram B semen respectively. However, in the case of prolificacy rate, 44.44% and 40 % of the ewes lambed from using semen of ram A and B, respectively. There was no significant difference (p>0.05) in pregnancy and prolificacy rates based on semen from the two rams. In conclusion, in this research study, ram semen had no significant effect on pregnancy and prolificacy rates using laparoscopic AI on Lacaune sheep. This could be due to the fact that the rams had very good quality semen. Evaluation of ram semen, accompanied with appropriate ewe selection based on age and rightful deposition of semen could lead to better and more consistent results. Overall this could contribute to the successful application of laparoscopic artificial insemination in Lacaune sheep production systems for enhanced productivity.

There has been considerable research on techniques for artificial insemination of sheep with frozen ram semen (Maxwell, 1984). Acceptable pregnancy rates were reported following ‘two-step’ dilution and freezing of semen in P.V.C. ‘ministraws’ (Colas, 1975; Colas & Guerin, 1981); however, other workers have obtained poor fertility following cervical insemination with semen frozen in straws (Maxwell, etal. 1980; Tervit elal. 1984).

One of the major limitations to the widespread use of artificial insemination (AI) in the United Kingdom (UK) sheep industry is that with frozen-thawed semen current insemination techniques result in lowered fertility. Consequently, only fresh or liquid-chilled ram semen can be used if commercially acceptable conception rates are to be achieved.

Practical systems for the artificial insemination of sheep have been available for many years (reviewed by Maxwell, 1984). The traditional method is to separate from the flock ewes exhibiting a natural oestrus as identified by ‘teaser’ rams, and inseminate these ewes with freshly collected and diluted semen. The ewes are generally inseminated by suspension of the hindquarters over an elevated rail and deposition of the semen within the first fold of the cervix using a plastic pipette, speculum and headlamp (the cervical insemination method, Salamon, 1976).

Scrapie is the most common transmissible spongiform encephalopathy (TSE) in livestock. Natural contamination in sheep flocks is presumed to occur by maternal transmission to offspring. However, horizontal prion transmission from animal to animal exists and may be significant in sustaining and spreading contagion in the field. Artificial insemination is widely used in modern farming, and as large amounts of prion protein have been found in sheep sperm membrane, epididymal fluid and seminal plasma, horizontal transmission by this route was hypothesized since no clear information has been obtained on possible sexual transmission of TSE. We therefore tested the contamination levels of semen from scrapie-infected rams at different stages of incubation, including the clinical phase of the disease. We report here that under our experimental conditions ram semen did not transmit infectivity to scrapie-susceptible transgenic mice overexpressing the V136R154Q171 allele of the sheep prion (PRNP) gene. These results suggest that artificial insemination and natural mating have a very low or negligible potential for the transmission of scrapie in sheep flocks.

The current technique for artificial insemination (AI) of ewes during the breeding season necessitates the synchronisation of oestrus with progestagen sponges and PMSG, and involves depositing semen into the posterior cervix at a fixed time after sponge removal. Extensive field trials over a number of years in the UK have indicated that a single insemination using fresh diluted semen 56 h after sponge removal generally results in a conception rate of 70%, while conception rates following a single insemination of frozen-thawed semen 57 h after sponge removal have ranged from 19% to 34% (mean 28%). Giving two inseminations of frozen-thawed semen at 50 h and 60 h after sponge removal increased the overall mean conception rate, but only up to 48%. This inability to achieve acceptable conception rates with frozen-thawed semen nullifies many of the potential benefits of AI in sheep flocks.It is well established that the cervix presents a major barrier to sperm transport in the ewe, particularly when oestrus has been synchronised with progestagens and PMSG.

The widespread use of artificial insemination (AI) in the United Kingdom sheep industry has been limited by the poor conception rates obtained after cervical insemination of frozen-thawed semen. The major problem in this respect is the impairment of sperm transport through the cervix, particularly when AI is used in conjunction with oestrus synchronisation.Previous studies (Killeen and Caffery, 1982; Maxwell, 1984) have indicated that a laparo-scopic technique for intrauterine insemination in ewes may overcome such limitations. At the moment, however, sufficient data on the optimum time of insemination and sperm doses required to maximise fertility in British breeds are not available. The present study was conducted to establish the optimum time of intrauterine insemination using frozen-thawed semen.

Artificial insemination, especially with the use of frozen semen, is one of the important tools for embryo transfer program in sheep. The present study investigated the effects of insemination times, breeds, and two inseminators on the fertility of ewes intrauterinally inseminated with frozen–thawed ram semen imported from New Zealand. At 8 sheep farms located in Hokkaido, Japan, during the breeding season (October to December) in 2005, a total of 64 mature (1- to 6-year old) Suffolk (32 heads) and Polled Dorset (32 heads) ewes were used. The ewes were treated with controlled intravaginal drug release (CIDR containing 0.3 g progesterone; Pharmacia & Upjohn, Ltd., Auckland, New Zealand) for 12 days and an injection of 500 IU equine chorionic gonadotropin one day before CIDR removal. The fixed-time intrauterine inseminations (early: 43–46 h; late: 47–50 h) after CIDR removal were performed using the frozen–thawed semen from a Suffolk and Polled Dorset ram by two inseminators. The effects of breeds (Suffolk and Polled Dorset), fixed-time insemination times (early and late phases), and two inseminators on pregnancy (number of pregnant ewes/number of ewes inseminated, 60 days after insemination) and lambing (number of lambed ewes/number of ewes inseminated) rates were analyzed by chi-square test. The prolificacy was compared by Student's t-test, and differences were also analyzed by Tukey's omega procedure. The effect of the different farms on fertility was not examined due to the small numbers of ewes per farm. Pregnancy (60.0 and 72.4%, respectively) and lambing (60.0 and 71.4%, respectively) rates were not significantly different between Suffolk and Polled Dorset ewes. The inseminators also did not affect pregnancy (62.6 and 68.8%) and lambing (62.6 and 67.7%) rates. For the insemination times, the lambing rate tended to be higher (P ≤ 0.10) in the early insemination than in the late insemination (76.7% and 53.6%, respectively). The present results show acceptable fertility in ewes inseminated with Suffolk and Polled Dorset frozen semen imported from New Zealand. The early intrauterine insemination (43–46 h after CIDR removal) tended to result in higher fertility than the late insemination (47–50 h after CIDR removal). From 38 lambed ewes, 60 newborn lambs were produced, and this has provided new blood lines of Suffolk and Polled Dorset sheep in Japan.

Includes bibliographical references (leaves 274-316) Examines several aspects of male reproduction in the sheep, and how these are related to fertility in the female when semen is introduced by natural mating or artificial insemination.

O melhoramento genético ovino carece de uma maior conexão genética entre os rebanhos, o que pode solucionado pelo uso mais intensivo do sêmen congelado. Entretanto, com os níveis tecnológicos atualmente disponíveis o sêmen congelado apenas pode ser empregado com eficácia diretamente no útero, dependendo de sincronização de estros e mão de obra especializada para as inseminações via laparoscopia. Uma outra alternativa é o uso de sêmen congelado com 200 milhões de espermatozóides por dose com inseminações efetuadas cerca de doze horas após a identificação do estro, preconizado para a inseminação artificial dos ovinos na Noruega pelos próprios produtores. O presente ensaio consta de uma adaptação local deste modelo com o objetivo geral de verificar a viabilidade de uso da inseminação cervical superficial com sêmen ovino congelado numa dose de 0,25 ml contendo 200 x 106 de espermatozóides em palhetas de 0,50 ml após cio natural, empregando baixo uso de insumos e mão de obra semi-qualificada. As observações foram procedidas em duas propriedades no Rio Grande do Sul, incluindo 1419 ovelhas das raças Merino, Ideal e Texel. Os resultados obtidos indicaram que as diferenças nas taxas de não retorno entre carneiros poderá ser minimizada através da utilização de outros métodos de análise e seleção de carneiros mais férteis após os procedimentos de congelamento/descongelamento, e, adicionalmente que a constatação de uma taxa de não retorno entre 25-35% nas distintas condições investigadas, permitem inferir que os sistemas investigados podem ser utilizados para interligar geneticamente rebanhos via uso de sêmen congelado.
A sheep improvement program depends on genetic connexion among flocks, which could be done by extensive use of frozen semen. However, nowadays-available technology just recommends the employment of frozen semen directly inside the uterine ambient through laparoscopy. Alternatively, there is a model recommended for Norway producers including frozen semen with 200 millions of sperms used in cervical superficial inseminations up to twelve hours from oestrus detection. The present essay is an local adaption of this system aiming to verify the viability of the employment of frozen semen for sheep reproduction in a volume of 0,25 ml, with 200 x 106 sperms in 0,50 ml straws, after natural oestrus, using low input resource and semi-qualified artificial insemination technicians. The observations were done in the two properties located at Rio Grande do Sul, including 1419 ewes from Merino, Ideal and Texel breeds. The results obtained indicate that the differences in non return rates among rams could be minimized by the employment of other methods of ram selection before the freezing procedures, and additionally the observed 25-35% non return rates in the distinct conditions investigated, permits to infer that the tested system could be useful to connect genetically the flocks using frozen semen.

Este estudo teve por objetivo avaliar os efeitos de dois diluentes comerciais, Dilutris® (SEMENCON – Produtos Agropecuários Ltda., Porto Alegre, RS, Brasil) e TQC Holding Plus® (Nutricell – Nutrientes Celulares Ltda., Campinas, SP, Brasil), na qualidade do sêmen, nas taxas de concepção utilizando inseminação artificial cervical (IAC) e por laparoscopia (IAL) e na reação inflamatória uterina após a inseminação laparoscópica. Para os testes in vitro do sêmen foram coletados seis ejaculados de dois carneiros. Cada ejaculado foi dividido em cinco frações de 0,20 mL, e acrescentado a cada fração o volume de diluidor equivalente a concentração da dose inseminante: para IAC (100x106 espermatozóides) e para IAL (40x106 espermatozóides), formando quatro tratamentos T1, T2, T3 e T4, respectivamente: Dilutris®/cervical; Dilutris®/laparoscopia; Holding®/cervical; Holding®/laparoscopia. Foram avaliadas a motilidade/ vigor, testes de termo-resistência e hiposmótico de cada fração. A motilidade e o vigor não diferiram entre os tratamentos e foram semelhantes aos verificados no sêmen fresco. No teste hiposmótico, os valores verificados no T4 e T1 foram semelhantes e não diferiram dos observados no sêmen fresco. Os valores observados nos tratamentos T2 e T3 não diferiram entre si, mas foram significativamente inferiores (P<0,05) aos verificados no T4. Os resultados do teste de TTR verificados em todos os tratamentos utilizados, foram superiores ao valor mínimo de 30% preconizado pelo CBRA. O T1 apresentou valor significativamente inferior (P<0,05) ao dos demais tratamentos. Para a inseminação artificial, 208 fêmeas tiveram o estro sincronizado com esponjas vaginais contendo 60 mg de MAP por 13 dias e aplicação de 400 UI de eCG no momento da retirada. Foram inseminadas pela via cervical (IAC) ou por laparoscopia (IAL), 54 horas e 60 horas, respectivamente, após a retirada do dispositivo intra-vaginal, com sêmen diluído com Dilutris®, Holding® ou solução fisiológica (Grupo controle). Independentemente do diluente utilizado, os índices obtidos na IAL foram superiores (P<0,05) aos obtidos pela IAC. Na IAC a taxa de gestação obtida no grupo inseminado com o diluente TQC Holding Plus® (45,6%), foi semelhante à verificada no grupo controle (48,9%). Já no grupo que foi inseminado com Dilutris®, a taxa de gestação (29%) foi inferior à obtida no grupo controle (P<0,05). Com relação aos aspectos histológicos, verificou-se um infiltrado inflamatório de neutrófilos de grau discreto a acentuado nos úteros inseminados por laparoscopia com Dilutris®, de ausente a moderado nos úteros inseminados com TQC Holding Plus®, e no grupo controle não houve presença de infiltrado inflamatório de neutrófilos. Podese concluir que na avaliação in vitro, o meio de manutenção de embriões TQC Holding Plus® não causou efeitos negativos na qualidade do sêmen, enquanto que o meio diluidor Dilutris® foi menos efetivo na manutenção da qualidade do sêmen. O local de deposição do sêmen teve influência significativa no índice de fertilidade (P<0,05). Por laparoscopia as taxas de gestação foram semelhantes independentemente do diluidor utilizado. Um maior número de avaliações uterinas são necessárias para um melhor conhecimento da reação inflamatória intra-uterina em ovinos inseminados por laparoscopia.
This study aims to assess the effects of two commercial diluents, Dilutris® (SEMENCON – Produtos Agropecuários Ltda., Porto Alegre, RS, Brazil) and TQC Holding Plus® (Nutricell – Nutrientes Celulares Ltda., Campinas, SP, Brazil), on semen quality, conception rates using Cervical Artificial Insemination (CAI) and Laparoscopic Artificial Insemination (LAI), and uterine inflammatory reactions after the laparoscopic insemination. For the in vitro tests with the semen, six ejaculates of two rams were collected. Each ejaculate was divided into five fractions of 0.20 mL, and we added to each fraction the volume of extender equivalent to the concentration of the inseminant dose: for CAI (100x106 spermatozoa) and for LAI (40x106 spermatozoa), forming four treatments T1, T2, T3, and T4, respectively: Dilutris®/cervical; Dilutris®/laparoscopy; Holding®/cervical; Holding®/laparoscopy. The motility/vigor, thermo-resistance and hypoosmotic tests of each fraction was evaluated. The motility and vigor were not different between the treatments and were similar to those verified in fresh semen. In the hypoosmotic test, the values verified in T4 and T1 were similar and were not different from those observed in fresh semen. The values observed in T2 and T3 treatments have not differed between them, but were significantly lower (P<0.05) to those verified in T4. Results of the TTR test verified in all used treatments were superior to the minimum value of 30% preconized by CBRA. T1 presented a significantly lower value (P<0.05) compared to the other treatments. For artificial insemination, 208 female had their estrus synchronized with vaginal sponges containing 60 mg of MAP for 13 days and the application of 400 UI of eCG at the moment of removal. They were inseminated by cervical via (CAI) or by laparoscopy (LAI), 54 and 60 hours, respectively, after the removal of the intravaginal device, with semen diluted with Dilutris®, Holding® or physiological solution (control group). Independently of the extender used, the obtained rates in the LAI were superior (P<0.05) to those obtained with the CAI. In CAI the pregnancy rate obtained in the inseminated group with the TQC Holding Plus® diluent (45.6%) was similar to the one verified in the control group (48.9%). In the group inseminated with Dilutris®, the pregnancy rate (29%) was inferior to the obtained in the control group (P<0.05). Related to the histological aspects, we verified a discreet to accentuated degree of neutrophils inflammatory infiltrate in the uterus inseminated by laparoscopy with Dilutris®, from absent to moderate in uterus inseminated with TQC Holding Plus®, and in the control group there was not inflammatory infiltrate of neutrophils. We can conclude that in the in vitro evaluation, the embryos maintenance means TQC Holding Plus® has not caused negative effects in the quality of the semen, while the Dilutris® extender was less effective to maintain the quality of the semen. The semen deposition site has a significant impact in the fertility rate (P<0.05). By laparoscopy the pregnancy rates were similar independently of the extender used. A larger number of uterine analyses are required for a better knowledge of the intrauterine inflammatory reaction in sheep inseminated by laparoscopy.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
O Objetivo deste estudo foi determinar o efeito da adição do surfactante lauril sulfato de sódio (Orvus es Paste OEP) e dos antioxidantes Trolox-C (6- hidroxi-2, 5,7,8-tetrametilcroman-2-acido carboxílico) e catalase ao meio diluidor, na motilidade espermática, integridade de membrana plasmática, acrossomal e mitocondrial, estádio de capacitação e geração de radicais livres no espermatozóide ovino pós-descongelação. Para isso, foram realizados dois experimentos. No Experimento 1, avaliou-se o efeito da adição do surfactante ao diluidor. O sêmen de 10 carneiros foi coletado por meio de vagina artificial e diluído para uma concentração final de 400x106 espermatozóides/mL no meio Tris-gema contendo OEP (0; 0,5 e 1%) ou no diluidor glicina-gema-leite (controle). A motilidade foi determinada pelo sistema computadorizado de análise de sêmen (CASA), a integridade de membrana pela combinação dos corantes fluorescente iodeto de propídio e diacetato de carboxifluoresceína (IP+DIC) e o estádio de capacitação pela técnica da CTC. Houve efeito significativo do tratamento em todos os parâmetros da motilidade, na integridade de membranas e na capacitação espermática. A adição de 0,5% ou 1% de OEP ao diluidor TRIS-gema aumentou significativamente (P<0,05) a motilidade, a integridade de membranas e o percentual de espermatozóides não capacitados, comparado ao controle. O diluidor TRIS 1 foi selecionado para utilização como meio base para o experimento 2. No Experimento 2, foi determinado o efeito da adição dos antioxidantes ao diluidor. O sêmen foi coletado e os seguintes tratamentos foram aplicados: T1- TRIS (controle), T2- TRO+ (diluidor T1 + Trolox, 50mM/108 espermatozóides), T3-CAT+ (diluidor T1 + catalase, 50mg/mL), T4- TRO/CAT+ (diluidor T1 + Trolox e Catalase, nas mesmas concentrações utilizadas no T2 e T3)...(Rsumo completo, clicar acesso eletrônico abaixo)
The aim of this study was to determine the effect of addition of surfactant sodium lauryl sulfate (Orvus es Paste OEP), and antioxidants, Trolox-C (6- hydroxy-2,5,7,8-tetramethylchroman-2-carboxilic acid) and catalase to an extender on the motility, plasmatic and acrosomal and mitochondrial membrane integrity, capacitation status and free radicals generation of post thaw ram spermatozoa. Two experiments were performed. In Experiment 1, the effect of addition of surfactant was evaluated. The semen was collected from ten rams by artificial vagina and it was diluted to a final concentration of 400x 106 sperm/mL in egg yolk-Tris extender containing OEP (0, 0.5 and 1%) or glycinegg yolk-milk extender (control). The sperm motility was evaluated using a computer-assisted sperm analysis (CASA); the membrane integrity was verified using the fluorescent stains (propidium iodide and carboxyfluorescein diacetate) and the capacitation status determined by CTC technique. There was a significant treatment effect in all parameters involving sperm motility, membrane integrity and spermatic capacitation. The addition of OEP 0.5% or 1% to the egg yolk-Tris extender improved (P<0.05) the motility and membrane integrity and the percentage of uncapacited spermatozoa compared to the control. Then, the TRIS 1 extender was selected to be used at experiment 2. Experiment 2: the Exp 2 aimmed to determine the effect of antioxidants addition to the extender. Semen was collected and these treatments were applied: T1 - egg yolk-Tris extender (control), T2- TRO+ (T1 extender +Trolox, 50mM/108 spermatozoa), T3- CAT+ (T1 extender + catalase, 50mg/mL) and T4 TRO/CAT+ (T1 extender + trolox and catalase on the concentrations used in T2 and T3). Motility was determined by CASA system, plasmatic and acrosomal 4 membrane integrity and mitochondrial function were evaluated with PI, FITCPSA and JC-1 association...(Complete abstract, click electronic address below)

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The aim of the present study was to assess the in vitro and in vivo viability of sperm cells following the addition of diluent in the refrigeration process of sheep semen and the fertilization of oocytes following the insemination of superovulated ewes. In Experiment I, three ejaculates from each of three Dorper breeders were used, collected with an artificial vagina during three repetitions with three-day intervals. The macroscopic and microscopic characteristics of the semen were analyzed before and after the pooling, analyzing sperm concentration, DNA integrity and acrosome integrity as well. The pooled semen was divided into five equal parts. Dilution was performed (1:3, semen:diluent) to establish the diluent groups: Equimix (DI), Laiciphos Green Ovine (DII), FR 4 (DIII), Equimix-Yolk [Equimix with 20% egg yolk (DIV)] and Tris-Yolk (DV; control). Each group was subdivided in quadruplicate, refrigerated and kept at 4 °C until the evaluations (MIP, vigor, DNA integrity and acrosome integrity), corresponding to 0, 12, 24, 36 and 48 hours. In the in vitro assessments, DI exhibited the greatest drop in MIP at 12 h in comparison to the other groups (p<0.05). At 24 h, DII, DIV and DV exhibited the highest MIP (p<0.05), with no significant differences between one another (p>0.05). At 48 h, DII and DV were superior to the other groups (p<0.05). Regarding vigor, DII and DV had higher values (p<0.05) than DI and DIII at 12 hours and DIV had the highest values at 24 hours (p<0.05). In all groups, there was total preservation of DNA integrity and a high number of spermatozoids with intact acrosomes for all the intervals studied. In Experiment II, the same collection method and processing of the ejaculates from the three Dorper breeders were performed. A pool was formed of the threeejaculates of each animal, divided into two equal parts at a 1:3 proportion in order to establish the experimental groups: Equimix-Yolk (DI) and Tris-Yolk (DII; control). Each group was subdivided into two aliquots: fresh – F (F-DI and F-DII), which was used immediately; and refrigerated – R (R-DI and R-DII), which was kept at 4 °C for a storage time of 24 hours. Laparoscopic inseminations were preformed with an inseminate volume of 0.25 mL per uterine horn, which was when the ovary evaluations were performed. Thirty-nine embryo harvesting procedures were performed, 19 using refrigerated semen and (R-DI and R-DII) and 20 using fresh semen (F-DI and F-DII). In the in vivo test, a general rate of 71.0% (237/334) of fertilized structures was obtained, 59.3% (198/334) of which were viable embryos. There was no significant variation (p>0.05) between the types of semen and diluents. Among the total number of embryos, 86.4% exhibited quality Grades I and II, with the refrigerated semen of R-DI obtaining the best percentage (100%)(p<0.05). The ovarian status at the time of insemination affected fertilization, as better results were obtained for the fresh semen of F-DI when the ovary was ovulating. For F-DII, this status exhibited a smaller number of fertilized structures (p<0.05). At the end of the experiments, it was concluded that both the Laiciphos Green Ovine and Tris-Yolk can be used in the conservation of semen at 4 °C for 48 hours, whereas Equimix added with 20% egg yolk is recommended for use in semen storage (4 °C) of up to 24 hours. The refrigeration of ovine semen at 4 °C for 24 hours is viable for use inembryo transference programs. Equimix added with 20% egg yolk resulted in a fertilization rate and embryo quality similar to the traditional Tris-Yolk.
Neste estudo objetivou-se avaliar a viabilidade in vitro e in vivo das células espermáticas após a adição de diluente no processo de refrigeração do sêmen ovino, e na fertilização de oócitos após inseminação de fêmeas ovinas superovuladas. No Experimento I foram utilizados três ejaculados de cada um dos três reprodutores Dorper, coletados com vagina artificial a intervalo de 3 dias, em três repetições. As características macro e microscópicas do sêmen foram analisadas antes e após a formação de um pool, além da concentração espermática, integridade do DNA e do acrossoma. O pool foi dividido em cinco partes iguais, procedeu-se com a diluição (1:3, sêmen:diluente) para constituir os respectivos grupos de diluentes: Equimix (DI), Laiciphos Green Ovine (DII), FR 4 (DIII), Equimix-Gema – Equimix com 20% gema de ovo (DIV) e Tris-Gema (DV; controle). Cada grupo foi subdividido em quadruplicata, refrigerado e mantido a 4 °C até as avaliações (MIP, vigor, integridade do DNA e do acrossoma) correspondendo a 0, 12, 24, 36 e 48 horas. Nas avaliações in vitro do sêmen o DI apresentou maior queda de MIP às 12 h em relação aos demais grupos (p<0,05). Às 24 h os grupos DII, DIV e DV apresentaram a melhor MIP (p<0,05), não divergindo (p>0,05) entre si, enquanto que às 48 h o DII e o DV foram superiores (p<0.05) aos demais. Com relação ao vigor, os grupos DII e o DV apresentaram valores superiores (p<0,05) ao DI e DIII a partir das 12 horas e ao DIV a partir das 24 horas (p<0,05). Em todos os grupos de diluentes houve a preservação total da integridade do DNA e alto índice de espermatozóides com acrossoma intacto, para todos os intervalos avaliados.Para o Experimento II foi utilizada a mesma técnica para colheita e processamento dos ejaculados de três reprodutores Dorper. Formou-se um pool com três ejaculados de cada animal, dividiu-se em duas partes iguais diluídas na proporção 1:3 para constituir os respectivos grupos experimentais: Equimix-Gema (DI) e Tris-Gema (DII; controle). Cada grupo foi subdividido em outras duas alíquotas: fresco – F (F-DI e F-DII), que foi usado imediatamente, e refrigerado – R (R-DI e R-DII), mantido a 4 °C por 24 horas de armazenamento. Foram realizadas inseminações laparoscópicas, com volume inseminante de 0,25 mL por corno uterino, momento em que foram realizadas as avaliações dos ovários. Foram realizados 39 procedimentos de colheitas de embriões, em 19 foram utilizados sêmen refrigerado (R-DI e R-DII) e em 20 sêmen fresco (F-DI e F-DII). No teste in vivo obteve-se uma taxa geral de estruturas fertilizadas de 71,0% (237/334), sendo 59,3% (198/334) de embriões viáveis, o que não variou significativamente (p>0,05) entre os tipos de sêmen e de diluentes. No total dos embriões, 86,4% apresentaram qualidade de grau I e II, sendo o sêmen refrigerado do R-DI o de melhor percentual (100%) (p<0,05). O “status” ovariano no momento da inseminação interferiu na fertilização, observado-se melhores resultados para o sêmen fresco do F-DI quando o ovário se encontrava em ovulação. Para o F-DII, este status foi o que apresentou menor quantidade de estruturas fertilizadas (p<0,05). Ao final dos experimentos pode-se concluir que: o diluente Laiciphos Green Ovine, da mesma forma que o Tris-gema, pode ser utilizado na conservação do sêmen a 4 °C por 48 horas; enquanto o Equimix, acrescido de 20% de gema de ovo, recomenda-se que seja utilizado no armazenamento do sêmen (4 °C) por até 24 horas. É viável a refrigeração do sêmen ovino a 4°C por 24 horas para a utilização em programas de transferência de embriões; e que o diluidor Equimix, acrescido de 20% gema de ovo, resultou em taxa de fertilização e qualidade embrionária similares ao tradicional Tris-Gema.