Publicação
Comparison of the effect of dephereline versus buserelin on the synchronization of ovulation for fixed-time artificial insemination in Holstein Friesian cows
| Resumo: | The use of GnRH and its analogues on the precursors of today’s synchronization protocols for dairy cattle date back to the 1960s, and numerous studies have been conducted since then to understand and optimize their function. The present clinical study was divided into two parts; in the first section (n=663), two treatment groups were formed to compare the effect of two GnRH analogs —dephereline and buserelin — on synchronization for fixed-time artificial insemination in Holstein Friesian cows; the second section (n=398) aimed to evaluate and compare the effect of buserelin, as well as two different doses of dephereline, when administered on the 6th day after artificial insemination (AI), in non-repeat breeders (number of artificial inseminations less than or equal to 3) and repeat breeders (number of artificial inseminations greater than 3). In the first section of the clinical trial, the conception rate obtained was the same (32.7%) for both dephereline and buserelin-treated cows; no statistically significant differences were found in the conception rate between the two treated groups (Chi-square; P=0.89). Similarly, there were no significant differences in the conception rate for the group of primiparous cows (P=0.87) nor for the group of multiparous cows (P=0.95). In the second part of the trial, for non-repeat breeders, the conception rate was: 34.6% for cows injected with buserelin, 37% for the group injected with dephereline, 30.8% for cows injected with 2.5 times the therapeutic dose of dephereline, and 28.6% for the group injected with saline solution. Regarding repeat breeders, the conception rate obtained was: 27.1% for the group treated with buserelin, 25.5% for cows injected with dephereline, 26.7% for cows treated with 2.5 times the single dose of dephereline, and 29.8% for animals injected with saline solution. There were no significant differences between the four treatments used in conception rate, both for non-repeat breeders (P=0.8) and repeat breeders (P=0.98). The effect of other variables on the conception rate was also evaluated in both parts of the clinical trial, highlighting the negative effect associated with the number of lactations (P=0.02). This study concluded that although different treatments did not reveal significant differences in conception rate, the difference in costs between the two drugs may justify their use and bring economic advantages |
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| Autores principais: | Reis, Beatriz Santos Mestre Rosa |
| Assunto: | Buserelin Dephereline Fertility GnRH Synchronization protocols Buserelina Deferelina Fertilidade GnRH Protocolos de sincronização |
| Ano: | 2025 |
| País: | Portugal |
| Tipo de documento: | dissertação de mestrado |
| Tipo de acesso: | acesso aberto |
| Instituição associada: | Universidade de Lisboa |
| Idioma: | inglês |
| Origem: | Repositório da Universidade de Lisboa |
| Resumo: | The use of GnRH and its analogues on the precursors of today’s synchronization protocols for dairy cattle date back to the 1960s, and numerous studies have been conducted since then to understand and optimize their function. The present clinical study was divided into two parts; in the first section (n=663), two treatment groups were formed to compare the effect of two GnRH analogs —dephereline and buserelin — on synchronization for fixed-time artificial insemination in Holstein Friesian cows; the second section (n=398) aimed to evaluate and compare the effect of buserelin, as well as two different doses of dephereline, when administered on the 6th day after artificial insemination (AI), in non-repeat breeders (number of artificial inseminations less than or equal to 3) and repeat breeders (number of artificial inseminations greater than 3). In the first section of the clinical trial, the conception rate obtained was the same (32.7%) for both dephereline and buserelin-treated cows; no statistically significant differences were found in the conception rate between the two treated groups (Chi-square; P=0.89). Similarly, there were no significant differences in the conception rate for the group of primiparous cows (P=0.87) nor for the group of multiparous cows (P=0.95). In the second part of the trial, for non-repeat breeders, the conception rate was: 34.6% for cows injected with buserelin, 37% for the group injected with dephereline, 30.8% for cows injected with 2.5 times the therapeutic dose of dephereline, and 28.6% for the group injected with saline solution. Regarding repeat breeders, the conception rate obtained was: 27.1% for the group treated with buserelin, 25.5% for cows injected with dephereline, 26.7% for cows treated with 2.5 times the single dose of dephereline, and 29.8% for animals injected with saline solution. There were no significant differences between the four treatments used in conception rate, both for non-repeat breeders (P=0.8) and repeat breeders (P=0.98). The effect of other variables on the conception rate was also evaluated in both parts of the clinical trial, highlighting the negative effect associated with the number of lactations (P=0.02). This study concluded that although different treatments did not reveal significant differences in conception rate, the difference in costs between the two drugs may justify their use and bring economic advantages |
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