Protocols for fixed time artificial insemination and reproductive efficiency of dairy cows and heifers

Na busca de biot?cnicas economicamente vi?veis para a melhoria da efici?ncia reprodutiva na pecu?ria, objetivou-se com este trabalho avaliar diferentes protocolos de insemina??o artificial em tempo fixo (IATF) em vacas mult?paras e observar o efeito do mesmo protocolo comparando mult?paras e prim?paras observando-se a influ?ncia do horm?nio fol?culo estimulante (FSH-p) na IATF. Os tratamentos utilizados foram TControle, TFSH e TFNOV, que consistiram nos seguintes protocolos: TControle (n=35) - Dia 0, inser??o de dispositivo intravaginal de progesterona e aplica??o de 2 mg de benzoato de estradiol, intramuscular (IM); dia 8, retirada do dispositivo e aplica??o de 0,53 mg de PGF2? e 1 mg de benzoato de estradiol, IM; dia 10, IATF realizada 44 h ap?s a retirada do dispositivo; TFSH (n=36) - similar ao TControle, por?m com aplica??o no dia 8 de 15 mg de FSH-p; TFNOV (n=24)- similar ao TFSH, por?m utilizando-se novilhas. Ao final do trabalho observou-se que houve efeito (P0,05). Houve diferen?a (P0,05) entre protocolos, PV e ECC no retorno ao estro, na cobertura com o touro e prenhez acumulada. N?o houve efeito (P>0,05) entre os protocolos e retorno ao estro e as taxas de prenhez na IATF, cobertura do touro e acumulada. Mesmo o uso do FSH-p n?o influenciando a efici?ncia reprodutiva, a taxa de prenhez acumulada foi satisfat?ria em ambos tratamentos. Conclui-se a IATF como interessante biot?cnica para o uso na produ??o animal; por?m, ? importante que haja um bom acompanhamento nutricional dos animais, em raz?o da rela??o entre nutri??o e reprodu??o.Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES)Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2010.ABSTRACT In search of biotechnical economically feasible to improve reproductive efficiency in livestock, aimed to evaluate with this work different protocols for TAI in multiparous cows and observe the effect of the same protocol when comparing multiparous and primiparous cows and observing the influence of FSH-p in TAI. The treatments consisted of: TControl (n=35)- Day 0, insertion of intravaginal progesterone device and application of 2 mg estradiol benzoate, intramuscular (IM), Day 8, removed from the device and application of 0.53 mg PGF2? and 1 mg estradiol benzoate, IM; Day 10, TAI performed 44 h after removal of the device; TFSH (n=36)- similar to TControl, but with the application on day 8 of 15 mg of FSH-p; TFNOV (n=24)- similar to TFSH but using heifers. At the end of the work observed that was an interaction (P 0.05). There were difference (P 0.05) between protocols, body weight and body condition on return to estrus in coverage with the bull and accumulated pregnancy. There was no effect (P> 0.05) between the protocols and return to estrus and pregnancy rates of TAI, the bull and the accumulated coverage. Even the use of FSH-p does not influence the reproductive efficiency, the cumulative pregnancy rate was found satisfactory in both treatments, thus concludes the TAI as interesting biotech for use in animal production, but it is important to have a good nutritional monitoring of animals, because the relationship between nutrition and reproduction