Sincronização de cio de vacas mertolengas e inseminação artificial a tempo fixo com sémen de touro brahman
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2011
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O maior rendimento num efectivo de bovinos de carne são os vitelos. O cruzamento de Bos indicus com Bos taurus tem vindo a ser praticado em vários Países como os EUA e o Brasil. A descendência daqui resultante mostra vantagens em relação às raças puras, desde a sua criação, que exige poucos custos, até ao maior lucro proveniente da sua venda. Assim, torna-se interessante explorar esta prática em Portugal onde o custo de produção é significativamente mais alto.
A fim de evitar perdas de tempo na detecção de cio e permitir a aplicação de Inseminação Artificial a Tempo Fixo, hoje em dia são frequentemente utilizados protocolos de sincronização de cio e ovulação.
Este trabalho teve como objectivo avaliar a influência da gonadotrofina coriónica equina, associada a uma progesterona e prostaglandina na sincronização do estro e da ovulação, sobre a taxa de sincronização e fertilização em vacas de carne Mertolengas (Bos taurus) IATF com sémen de touro de Brahman (Bos indicus).
Foram seleccionadas 20 vacas Mertolengas cíclicas e com uma condição corporal entre 2 e 3,5 (escala de 1 a 5, Houghton et al., 1990).
No dia 0 foi implantado a todos os animais um implante intravaginal de progesterona (CIDR®; 1,9g; Pfizer). No dia 8 administrou-se prostanglandina F2α (Dinolytic®; 5ml; IM; Pfizer). No dia 9 foi aplicada Gonadotrofina Coriónica (Intergonan® 6000UI; IM; Intervet) e o CIDR® (Pfizer) foi retirado. No dia 11 de tratamento, em horário pré-estabelecido, 48horas após a injecção de eCG foi realizada inseminaçao artificial de todos os animais com sémen de touro Brahman.
A sincronização de cio neste estudo teve uma taxa de sucesso de 90% (18/20) e uma taxa de concepção de 40% (8/20). Com o cruzamento destas duas raças é esperado criar uma descendência capaz de produzir vitelos de boa qualidade e com o menor custo possível.
The main sources of income to a herd of beef cattle are the calves. Cross breeding of Bos indicus and Bos taurus has become a growing tendency in countries such as the USA and Brazil due to the advantages that the offspring hold against pure breeds which include the low cost of livestock farming and higher level of profit from sales. Putting this concept in practice could be an interesting alternative for farming in Portugal, where costs are significantly higher. Estrus sychronization protocoles are frequently used to control ovulation so that the females can be bred and artificially inseminated at approximately the same time. The aims of this dissertation were to evaluate the influence of equine chorionic gonadotropin associated with progestin and prostaglandin on estrus and ovulation sychronization as well as fertilization success rates in Mertolenga (Bos taurus) beef cattle time inseminated with Brahman (Bos indicus) bull semen. 20 Mertolenga females exhibiting regular estrous cycles, with a body score between 2 and 3,5 (on a scale from 1 to 5, Houghton et al., 1990) were selected. Estrous synchronization using the intravaginal device CIDR® (1,9g;Pfizer) consists of placing the progestin device in the vagina on day 0, giving an injection of prostaglandin F2α Dinolytic® (5ml; IM; Pfizer) on day 8 and on day 9 administering an Chorionic Gonadotropin injection Intergonan® 6000UI (IM; Intervet) on removal of the intravaginal device. On day 11, 48 hours after the eCG injection, all females were artificially inseminated with Brahman bull semen. Estrus synchronization rates of this study were of 18/20 (90% success rate), while conception rates were of 8/20 (40% success rate). The hope in the near future is to provide good quality offspring at the lowest possible cost through the crossing of these two breeds.
The main sources of income to a herd of beef cattle are the calves. Cross breeding of Bos indicus and Bos taurus has become a growing tendency in countries such as the USA and Brazil due to the advantages that the offspring hold against pure breeds which include the low cost of livestock farming and higher level of profit from sales. Putting this concept in practice could be an interesting alternative for farming in Portugal, where costs are significantly higher. Estrus sychronization protocoles are frequently used to control ovulation so that the females can be bred and artificially inseminated at approximately the same time. The aims of this dissertation were to evaluate the influence of equine chorionic gonadotropin associated with progestin and prostaglandin on estrus and ovulation sychronization as well as fertilization success rates in Mertolenga (Bos taurus) beef cattle time inseminated with Brahman (Bos indicus) bull semen. 20 Mertolenga females exhibiting regular estrous cycles, with a body score between 2 and 3,5 (on a scale from 1 to 5, Houghton et al., 1990) were selected. Estrous synchronization using the intravaginal device CIDR® (1,9g;Pfizer) consists of placing the progestin device in the vagina on day 0, giving an injection of prostaglandin F2α Dinolytic® (5ml; IM; Pfizer) on day 8 and on day 9 administering an Chorionic Gonadotropin injection Intergonan® 6000UI (IM; Intervet) on removal of the intravaginal device. On day 11, 48 hours after the eCG injection, all females were artificially inseminated with Brahman bull semen. Estrus synchronization rates of this study were of 18/20 (90% success rate), while conception rates were of 8/20 (40% success rate). The hope in the near future is to provide good quality offspring at the lowest possible cost through the crossing of these two breeds.
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Orientação: Dário Guerreiro
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INSEMINAÇÃO ARTIFICIAL VETERINÁRIA, BOVÍDEOS, VETERINÁRIA, ARTIFICIAL INSEMINATION OF ANIMALS, BOVIDS, VETERINARY MEDICINE, MESTRADO INTEGRADO EM MEDICINA VETERINÁRIA, MEDICINA VETERINÁRIA, REPRODUÇÃO ANIMAL, ANIMAL BREEDING