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Authors
Advisor(s)
Abstract(s)
As características do sémen depende de fatores genéticos, individuais, ambientais e
comportamentais. As técnicas de recolha, de preservação e de inseminação artificial (IA)
influenciam a taxa de fertilidade pós-IA. Nos caprinos, a preservação do sémen apresenta uma
dificuldade extra relativamente à preservação de sémen de outras espécies de interesse
zootécnico. O seu plasma contém enzimas que interagem com os diluidores seminais à base de
gema de ovo e de leite desnatado e que podem prejudicar a integridade da membrana
plasmática, a mobilidade e a viabilidade dos espermatozóides, ou seja, que podem afetar
negativamente a taxa de fertilidade pós-IA. Neste sentido, vários autores sugerem que o sémen
dos bodes deve ser lavado (remoção do plasma seminal) antes deste ser refrigerado ou
congelado.
O presente trabalho foi desenvolvido com o objetivo de estudar os efeitos da raça (Serrana
vs. Preta de Montesinho) e da lavagem do sémen (cabras Pretas de Montesinho) sobre a taxa de
fertilidade pós-IA cervical com sémen refrigerado. Ele foi realizado em Bragança (Portugal), nas
Quintas de Santa Apolónia e do Pinheiro Manso, entre 3 de abril e 8 de junho de 2023. Para o
efeito foram utilizadas 26 cabras da raça Serranas, ecótipo transmontano, e 35 cabras da raça
Preta de Montesinho, respetivamente, com idades entre 2-9 e 1-6 anos. Como dadores de sémen
foram utilizados 4 bodes, 2 Serranos, ecótipo transmontano, e 2 Pretos de Montesinho. Foram
avaliados os efeitos do estado fisiológico inicial das cabras (cíclicas ou anéstricas), da resposta ao
tratamento de controlo reprodutivo, das características seminais e do efeito da lavagem do
sémen sobre a taxa de fertilidade pós-IA com sémen refrigerado.
Na primeira quinzena de abril todas as cabras Serranas e Pretas de Montesinho estavam
cíclicas. Todas elas responderam ao tratamento de controlo reprodutivo. A qualidade do sémen
dos bodes Serranos afetou a taxa de fertilidade. O mesmo não sucedeu com o sémen dos bodes
Pretos de Montesinho. Quarenta e um dias pós-IA, 88,5% das cabras Serranas e 85,7% das cabras
Pretas de Montesinho estavam gestantes. A raça não condicionou a taxa de fertilidade. Na raça
Preta de Montesinho, a lavagem do sémen pré-refrigeração não influenciou a taxa de fertilidade.
Semen characteristics depend on genetic, individual, environmental and behavior factors. Semen collection, preservation and artificial insemination (AI) techniques influence the post-AI fertility rate. In goats, semen preservation presents an additional difficulty compared to other farm species’ semen preservation. Its seminal plasma contains enzymes that interact with seminal extenders based on egg yolk and skimmed milk, harming membrane integrity and sperm motility and viability and reducing fertility rate. Consequently, several researchers suggest that buck semen should be washed (removal of the seminal plasma) previous to cooling or freezing. The main goal of this work was to study the effects of breeds (Serrana vs. Preta de Montesinho) and semen washing (Preta de Montesinho) on the fertility rate post-cervical AI with cooled semen. It was conducted in Braganza (Portugal) between April 3 and June 8, 2023, using 26 Serrana, ecotype Transmontano, and 35 Pretas de Montesinho goats, aging between 2-9 and 1-6 years, respectively. Two bucks of each breed were used as semen donors. The effects of the initial physiological state (cycling or non-cycling), the response to reproductive control treatment, the semen characteristics and the semen washing on the fertility rate post-AI with cooled semen were evaluated. In the first fortnight of April, all Serrana and Preta de Montesinho goats were cycling. All of them responded to the reproductive control treatment. Semen characteristics affected the fertility rate of the Serrana but not the Preta de Montesinho goats. Forty-one days post-AI, 88.5% of the Serrana and 85.7% of the Preta de Montesinho goats were pregnant. Breeds had no effect on the fertility rate. In the Preta de Montesinho breed, semen washing had no effect on the fertility rate.
Semen characteristics depend on genetic, individual, environmental and behavior factors. Semen collection, preservation and artificial insemination (AI) techniques influence the post-AI fertility rate. In goats, semen preservation presents an additional difficulty compared to other farm species’ semen preservation. Its seminal plasma contains enzymes that interact with seminal extenders based on egg yolk and skimmed milk, harming membrane integrity and sperm motility and viability and reducing fertility rate. Consequently, several researchers suggest that buck semen should be washed (removal of the seminal plasma) previous to cooling or freezing. The main goal of this work was to study the effects of breeds (Serrana vs. Preta de Montesinho) and semen washing (Preta de Montesinho) on the fertility rate post-cervical AI with cooled semen. It was conducted in Braganza (Portugal) between April 3 and June 8, 2023, using 26 Serrana, ecotype Transmontano, and 35 Pretas de Montesinho goats, aging between 2-9 and 1-6 years, respectively. Two bucks of each breed were used as semen donors. The effects of the initial physiological state (cycling or non-cycling), the response to reproductive control treatment, the semen characteristics and the semen washing on the fertility rate post-AI with cooled semen were evaluated. In the first fortnight of April, all Serrana and Preta de Montesinho goats were cycling. All of them responded to the reproductive control treatment. Semen characteristics affected the fertility rate of the Serrana but not the Preta de Montesinho goats. Forty-one days post-AI, 88.5% of the Serrana and 85.7% of the Preta de Montesinho goats were pregnant. Breeds had no effect on the fertility rate. In the Preta de Montesinho breed, semen washing had no effect on the fertility rate.
Description
Mestrado dupla diplomação com o Instituito Federal de Ciência, Tecnologia e Educação do Sul de Minas Gerais
Keywords
Cabras Serranas Pretas de Montesinho Sémen Lavagem Taxa de fertilidade