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Fatores que influenciam a taxa de conceção em bovinos sujeitos a inseminação artificial
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Abstract(s)
O objetivo deste estudo foi avaliar a influência de alguns fatores na taxa de conceção (TC) de bovinos sujeitos a inseminação artificial (IA). Os fatores analisados foram: tipo de cio (natural ou induzido), estação do ano, ano de inseminação, sémen utilizado (raça, convencional, sexado fêmea ou SpermVital), aptidão do animal inseminado (leite ou carne), paridade (nulípara ou parípara) e exploração.
Para tal foram recolhidos dados entre Outubro de 2014 e Março de 2016, em várias explorações de leite e de carne, dos distritos de Aveiro e Coimbra, com dimensão máxima do efetivo adulto de 50 animais. Foram considerados 461 procedimentos de IA, após deteção de cio natural ou induzido por um de três protocolos: Ovsynch, Presynch ou colocação de Dispositivo de Libertação Intravaginal de Progesterona. Utilizou-se sémen das raças Frísia, Montbéliarde, Vermelho Norueguês, Pardo Suíço, Limousine, Angus, Charolês e Marinhoa. O diagnóstico de gestação foi feito por palpação retal entre os 30 e os 60 dias, tendo a confirmação ocorrido 15 a 30 dias após o primeiro diagnóstico.
Após análise estatística, apenas a paridade (p=0,004) e o tipo de sémen (p=0,005) foram considerados significativos na influência da TC. Baseado nas estimativas de odds ratio, as nulíparas obtiveram 2,319 em relação às multíparas, com TC de 62,07% vs. 47,58%, respetivamente. Para além da paridade, o tipo de sémen também influenciou a TC. De entre os tipos de sémen utilizados, sexado fêmea, SpermVital e convencional, a TC foi superior no último caso (15,38%, 41,03% e 52,29% respetivamente).
The aim of this study was to evaluate the influence of major factors in the conception rate (TC) of cattle subject to artificial insemination (IA). The studied factors were: type of heat (natural or induced), season, year of insemination, semen used (breed, conventional, sexed female and SpermVital), animal aptitude (dairy or beef), parity (nulliparous or pariparous) and inner farm factors. For such purpose, data was collected from October 2014 to March 2016, on several dairy and beef farms in the districts of Aveiro and Coimbra, with a maximum herd size of 50 animals. A total of 461 AI procedures were contemplated, after natural or induced estrus detection by three protocols: Ovsynch, Presynch or placement of an Intravaginal Progesterone release device. Semen from different breeds was used, as follows: Friesian, Montbéliard, Red Norwegian, Brown Swiss, Limousine, Angus, Charolaise and Marinhoa. Pregnancy diagnosis was made by rectal palpation between 30 and 60 days’ post-insemination, and confirmation occurred 15 to 30 days after the first diagnosis. After statistical analysis, only the parity (p = 0,004) and class of sperm (p = 0,005) were considered to significantly influence TC. Based on estimates of odds ratios, the nulliparous group obtained 2,319 compared to multiparous with TC 62,07% vs. 47,58%, respectively. Aside from parity, the type of semen also influenced TC. Among the semen classes used, female sexed, SpermVital and conventional, TC was superior in the latter case (15,38%, 41,03% and 52,29% respectively).
The aim of this study was to evaluate the influence of major factors in the conception rate (TC) of cattle subject to artificial insemination (IA). The studied factors were: type of heat (natural or induced), season, year of insemination, semen used (breed, conventional, sexed female and SpermVital), animal aptitude (dairy or beef), parity (nulliparous or pariparous) and inner farm factors. For such purpose, data was collected from October 2014 to March 2016, on several dairy and beef farms in the districts of Aveiro and Coimbra, with a maximum herd size of 50 animals. A total of 461 AI procedures were contemplated, after natural or induced estrus detection by three protocols: Ovsynch, Presynch or placement of an Intravaginal Progesterone release device. Semen from different breeds was used, as follows: Friesian, Montbéliard, Red Norwegian, Brown Swiss, Limousine, Angus, Charolaise and Marinhoa. Pregnancy diagnosis was made by rectal palpation between 30 and 60 days’ post-insemination, and confirmation occurred 15 to 30 days after the first diagnosis. After statistical analysis, only the parity (p = 0,004) and class of sperm (p = 0,005) were considered to significantly influence TC. Based on estimates of odds ratios, the nulliparous group obtained 2,319 compared to multiparous with TC 62,07% vs. 47,58%, respectively. Aside from parity, the type of semen also influenced TC. Among the semen classes used, female sexed, SpermVital and conventional, TC was superior in the latter case (15,38%, 41,03% and 52,29% respectively).
Description
Keywords
Inseminação artificial Paridade Sémen Taxa de conceção Artificial insemination Parity Semen Conception rate