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Abstract(s)
Para que uma exploração consiga atingir sucesso, um dos fatores que não pode ser desprezado é o maneio reprodutivo. Assim, o produtor deve assegurar que dispõe das melhores ferramentas e conhecimentos para que todos os seus animais consigam alcançar a melhor performance reprodutiva possível. Assim, esta dissertação tem com objetivo o estudo de fatores que influenciam o sucesso da inseminação artificial (IA) numa vacaria leiteira de alta produção. Para tal, este trabalho consiste em dois estudos observacionais retrospetivos: uma delas focada em vacas e a segunda, em novilhas. No estudo com as vacas, os fatores estudados foram o inseminador, o touro dador do sémen, a ocorrência ou não de um puerpério saudável, o intervalo de tempo entre o parto e a primeira inseminação, a condição corporal antes do início do protocolo hormonal e o número de partos de cada vaca. No estudo envolvendo as novilhas, os fatores avaliados foram a idade das novilhas, o inseminador, o macho dador do sémen e a utilização ou não de um protocolo hormonal de indução/sincronização da ovulação. Como resultados obtidos no estudo das vacas, concluiu-se que, em termos estatísticos, o número de partos de cada vaca, o touro dador do sémen e o inseminador revelaram influência significativa no resultado da IA. Verificou-se que a probabilidade de a vaca ficar gestante diminuiu nas vacas multíparas, relativamente às primíparas e que, registaram-se variações significativas nos resultados obtidos por cada inseminador e por cada touro. Apesar de os outros parâmetros não terem tido significância estatística relativamente à taxa de gestação, fatores como a ocorrência ou não de um puerpério saudável e a condição corporal antes do início do protocolo hormonal, observaram-se resultados dignos de serem discutidos. Por fim, no estudo com as novilhas não foram encontradas relações estatisticamente significativas nas relações estudadas, contudo foi na mesma possível retirar certas conclusões das relações estudadas. Na análise comparativa entre as que foram sujeitas a um protocolo hormonal de sincronização e as inseminadas após deteção de cio natural, registou-se uma quebra da fertilidade das primeiras comparativamente às segundas e, mais uma vez, foram identificadas diferenças na taxa de sucesso da IA de cada inseminador e do touro dador do sémen
ABSTRACT - The influence of some factors on the effectiveness of artificial insemination in a high-production dairy herd - In order for a farm to achieve success, one of the factors that cannot be overlooked is reproductive management. Therefore, the producer must ensure that they have the best tools and knowledge to ensure that all their animals can achieve the best possible reproductive performance. Thus, the objective of this dissertation is to study the factors that influence the success of artificial insemination (AI) in a high-production dairy herd. To do this, this work consists of two retrospective observational studies: one focused on cows and the second on heifers. In the study with cows, the factors studied were the inseminator, the bull providing the semen, the occurrence or not of a healthy postpartum period, the time interval between calving and the first insemination, the body condition before the start of the hormonal protocol, and the number of calvings for each cow. In the study involving heifers, the evaluated factors were the age of the heifers, the inseminator, the male donor of semen, and the use or not of a hormonal protocol for ovulation induction/synchronization. As for the results obtained in the study of cows, it was concluded that, statistically, the number of calvings for each cow, the bull providing the semen, and the inseminator showed a significant influence on the outcome of AI. It was found that the probability of a cow becoming pregnant decreased in multiparous cows compared to primiparous ones, and significant variations were observed in the results obtained by each inseminator and each bull. Although the other parameters did not have statistical significance regarding the pregnancy rate, factors such as the occurrence or not of a healthy postpartum period and the body condition before the start of the hormonal protocol showed results worthy of discussion. Finally, in the study with heifers, statistically significant relationships were not found in the studied relationships; however, it was still possible to draw certain conclusions from the relationships studied. In the comparative analysis between those subjected to a hormonal synchronization protocol and those inseminated after natural estrus detection, a decrease in fertility of the former compared to the latter was observed, and once again, differences in the success rate of AI were identified for each inseminator and the bull providing the semen.
ABSTRACT - The influence of some factors on the effectiveness of artificial insemination in a high-production dairy herd - In order for a farm to achieve success, one of the factors that cannot be overlooked is reproductive management. Therefore, the producer must ensure that they have the best tools and knowledge to ensure that all their animals can achieve the best possible reproductive performance. Thus, the objective of this dissertation is to study the factors that influence the success of artificial insemination (AI) in a high-production dairy herd. To do this, this work consists of two retrospective observational studies: one focused on cows and the second on heifers. In the study with cows, the factors studied were the inseminator, the bull providing the semen, the occurrence or not of a healthy postpartum period, the time interval between calving and the first insemination, the body condition before the start of the hormonal protocol, and the number of calvings for each cow. In the study involving heifers, the evaluated factors were the age of the heifers, the inseminator, the male donor of semen, and the use or not of a hormonal protocol for ovulation induction/synchronization. As for the results obtained in the study of cows, it was concluded that, statistically, the number of calvings for each cow, the bull providing the semen, and the inseminator showed a significant influence on the outcome of AI. It was found that the probability of a cow becoming pregnant decreased in multiparous cows compared to primiparous ones, and significant variations were observed in the results obtained by each inseminator and each bull. Although the other parameters did not have statistical significance regarding the pregnancy rate, factors such as the occurrence or not of a healthy postpartum period and the body condition before the start of the hormonal protocol showed results worthy of discussion. Finally, in the study with heifers, statistically significant relationships were not found in the studied relationships; however, it was still possible to draw certain conclusions from the relationships studied. In the comparative analysis between those subjected to a hormonal synchronization protocol and those inseminated after natural estrus detection, a decrease in fertility of the former compared to the latter was observed, and once again, differences in the success rate of AI were identified for each inseminator and the bull providing the semen.
Description
Dissertação de Mestrado Integrado em Medicina Veterinária, área científica de Clínica
Keywords
Fatores Inseminação artificial Novilha Vaca Factors Artificial Insemination Heifers Cows
Pedagogical Context
Citation
Prazeres JGB. 2023. A influência de alguns fatores na eficácia da inseminação artificial numa vacaria de leite de alta produção [dissertação de mestrado]. Lisboa: FMV-Universidade de Lisboa
Publisher
Universidade de Lisboa, Faculdade de Medicina Veterinária