GONADOTHOPIN RELEASING HORMONE (GNRH) AND EQUINE CHORIONIC GONADOTROPIN (ECG) IMPROVE THE PREGNANCY RATE ON PROTOCOLS FOR TIMED-ARTIFICIAL INSEMINATION IN BEEF CATTLE
Palavras-chave:
fixed-time artificial insemination, beef cattle, estrus synchronization, GnRH, eCGResumo
O estudo teve como objetivo verificar a influência do GnRH e eCG em protocolos de IATF para melhorar a taxa de prenhez (TP) em bovinos de corte, tratados anteriormente com progesterona intravaginal de ação prolongada, em estação de monta de 90 dias. Um total de
660 fêmeas foi dividido em cinco grupos: (TAI1) injeção de 1,0mg de benzoato de estradiol
(BE) e P4 em d0, remoção de P4 e 0,075mg de prostaglandina F2a em d9, 1,0mg de BE no
d10, e TAI 32h (n = 120); (TAI2) mesmo que TAI1, mas a inclusão de 500ug de GnRH em
IA (n = 120); (TAI3) mesmo que TAI1, mas a inclusão de 400 UI de eCG no d10 (n = 120);
(TAI4) mesmo que TAI3, mas a inclusão de 500ug de GnRH em IA (n = 120); (5) não
sincronização do estro, mas servido por monta natural (MN, n = 180). Quarenta e cinco dias
após a TAI, a TAI1, TAI2, TAI3 e grupo TAI4 foram deixados com os touros por 45 d. A
prenhez foi determinada por ultrassonografia em d45 depois da TAI e em d120 após todos os
tratamentos. Não houve diferenças na TP entre os quatro protocolos de TAI em d45 (vacas:
TAI1 = 48,0%, TAI2 = 53,8%, TAI3 = 57,6%, TAI4 = 58,3%; novilhas: TAI1 = 53,3%, TAI2
= 57,1%, TAI3 = 57,1%, TAI4 = 56,2%). A TP, após a estação de monta de 90 dias foi maior
em todos os grupos de vacas TAI (P<0,0001) em comparação com MN, com exceção de
novilhas (P>0,05). As vacas e novilhas foram analisadas em conjunto, e não foram
encontradas diferenças entre os grupos. Concluiu-se que os protocolos de TAI, utilizando
GnRH ou eCG sozinho ou em conjunto, contribuem de forma significativa para melhorar a
taxa de prenhez em fêmeas bovinas, quando submetidas a um tratamento prévio com
progesterona na fase reprodutiva.
Referências
IBGE, 2010. Brazilian Institute of Geography and Statistics. Municipal Livestock Production. 2010, Brazil.
Asbia, 2012. Report of the Brazilian Association of Artificial Insemination. Brazil.
Stevenson JS. Impact of reproductive technologies on dairy food production in the dairy industry. In: Lamb GC, DiLorenzo N. (ed). Current and future reproductive technologies and world food production. 2014; Springer, New York: 115-129.
Odde KG. A review of synchronization of estrus in postpartum cattle. Journal Animal Science. 1990; 68:817-830.
Ayres H, Martins CM, Ferreira RM, Mello JE, Dominguiza JH, Souza H. Et al. Effect of timing of estradiol benzoate administration upon synchronization of ovulation in suckling Nelore (Bos indicus) cows treated with a progesterone-releasing intravaginal device. Animal Reproduction Science. 2008; 109:77-87.
Pinheiro VG, Souza AF, Pergorer MF, Satrapa RA, Ereno RL, Trinca LA, et al. Effects of temporary calf removal and eCG on pregnancy rates to timed-insemination in progesterone-treated postpartum Nelore cows. Theriogenology. 2009; 71:519-524.
Sá Filho MF, Ayres H, Ferreira RM, Marques MO, Reis EL, Silva RCP. et al. Equine chorionic gonadotropin and gonadotropin-releasing hormone enhance fertility in a norgestomet-based, timed artificial lnsemination protocol in suckled Nelore (Bos indicus) cows. Theriogenology. 2010A ; 73:651-658.
Silveira EF, Kozicki LE, Segui MS, Weiss RR, Santos, IW, Bertol MAF. Comparison of long-term progesterone-based protocol on reproductive performance of prepubertal and pubertal beed heifers. Archives Veterinary Science. 2014; 19(1):1-6.
Borges LFK, Ferreira R, Siqueira LC, Boherer RC, Borstmann JW, Oliveira JFC, Gonçalves PBD. Artificial insemination system without estrous observation in suckled beef cows. Ciencia Rural. 2009; 39(2):496-501.
Ereno RL, Barreiros TRR, Seneda MM, Baruselli PS, Pegorer MF, Barros CM. Pregnancy rate of lactating Nelore cows treated with progesterone associated with temporary calf removal or application of equine chorionic gonadotropin. Brazilian Journal Animal Science. 2007; 36(5):1288-1294.
Meneghetti M, Sá Filho, OG, Peres, RFG, Lamb GC, Vasconcelos JLM. Fixed-time artificial insemination with estradiol and progesterone for Bos indicus cows I: Basis for development of protocols. Theriogenology. 2009; 72:179–189.
Pencai W.F, Kozicki LE, Costa, CEMP, Silva NL, Molleta JL, Motta JBO. Induction of estrus in postpartum crossbred cattle beef after use of different weaning protocols. Vet. Zoot. 2011; 45(1):53-62.
Gottschall CS, Almeida MR, Tolotti F, Magero J, Bittencourt HR, Mattos RC et al. Gregory, R.M. Evaluation of the reproductive performance at beef cows submitted to FTAI from application of GnRH, manifestation of estrus, reusing intravaginal devices and body condition score. Acta Science Veterinariae. 2012; 40(1):1-10.
Sá Filho OG, Meneghetti M, Peres RFG, Lamb GC, Vasconcelos JLM, Fixed-time artificial insemination with estradiol and progesterone for Bos indicus cows II: Strategies and factors affecting fertility. Theriogenology. 2008; 72:210-218.
Baruselli PS, Marques MO, Carvalho NAT, Madureira EH, Campos Filho EP. Effect of different protocols for fixed-time artificial insemination on reproductive performance of lactating beef cows. Revista Brasileira Reprodução Animal. 2002; 26:218-221.
Demeterco D, Henry DD, Mercadante VRG, Lamb GC, Gaievski FR, Weiss B, et al. The Effects of Intramuscular or Intravenous Injections of Gonadotropin Releasing Hormone at Fixed-Time Artificial Insemination on Pregnancy Rates of Bos Indicus Beef Cows. Brazilian Archives of Biology and Technology. 2014; 57(3):361-366.
Nascimento AB, Souza AH, Guenther JN, Costa FP, Sartori R, Wiltbank MC. Effects of treatment with human chorionic gonadotrophin or intravaginal progesterone-releasing device after AI on circulating progesterone concentrations in lactating dairy cows. Reprod Fertil Dev. 2013; 25(5):818-824.
Torres Jr JR, Melo WO, Elias AKS, Rodrigues LS, Penteado L, Baruselli PS. Technical and economic considerations on assisted reproduction in cattle. Revista Brasileira Reprodução Animal. 2009; 33:53-58.
Brazilian College of Animal Reproduction. (CBRA). Manual for andrological exam and evaluation of animal semen. 1998; 2 ed. 85 p.
SAS Institute Inc., Cary, NC, USA, 2003.
Dias CC, Wechsler FS, Day ML, Vasconcelos JL. Progesterone concentrations, exogenous equine chorionic gonadotropin, and timing of prostaglandin F(2alpha) treatment affect fertility in postpuberal Nelore heifers. Theriogenology. 2009; 72:378-385.
Peres RF, Claro Jr I, SÁ Filho, OG, Nogueira GP, Vasconcelos JL. Strategies to improve fertility in Bos indicus postpubertal heifers and nonlactating cows submitted to fixed-time artificial insemination. Theriogenology. 2009; 72(5):681-689.
Rossa LAF, Bertan CM, Almeida AB, Gaspar PS, Mazza PH, Binelli M.et al. Effect of eCG or estradiol benzoate associated to norgestomet on conception rate at inseminated postpartum beef cows. Brazilian Journal Veterinary Research Animal Science. 2009; 46(3):199-206.
Sá Filho MF, Torres-Júnio JR, Penteado L, Gimenes LU, Ferreira RM, Ayres H. et al. Equine chorionic gonadotropin improves the efficacy of a progestin-based fixed-time artificial insemination protocol in Nelore (Bos indicus) heifers. Animal Reproduction Science. 2010b; 118(2-4), 182-187.
Sá Filho MF, Crespilho AM, Santos JE, Perry GA, Baruselli PS. Ovarian follicle diameter at timed insemination and estrous response influence likelihood of ovulation and pregnancy after estrous synchronization with progesterone or progestin-based protocols in suckled Bos indicus cows. Animal Reproduction Science. 2010c ; 120(1-4):23-30.
Sá Filho MF, Baldrighi JM, Sales JNS, CrepaldiGA, Carvalho JBP, Bo GA. Induction of ovarian follicular wave emergence and ovulation in progestin-based timed artificial insemination protocols for Bos indicus cattle. Animal Reproduction Science. 2011; 129:132-139.
Sales JN, Crepaldi, GA, Girotto RW, Souza AH, Baruselli PS, Fixed-time AI protocols replacing eCG with a single dose of FSH were less effective in stimulating follicular growth, ovulation, and fertility in suckled-anestrus Nelore beef cows. Animal Reproduction Science. 2011; 124(1-2):12-18.
Colazo MG, Bó GA, Illuminat H, Meglia G, Schmidt EE, Bartolomé J. Fixed-timed artificial insemination in beef cattle using CIDR-Bdevices, progesterone and estradiol benzoate. Theriogenology. 1999; 51:404.
Cutaia L, Moreno D, Villata ML, Bó G. Synchrony of ovulation in beef cows treated with progesterone vaginal devices and estradiol benzoate administered at device removal or 24 hours later. Theriogenology. 2001; 55:408.
Mialot JP, Constant F, Dezaux P, Grimard B, Deletang F, Ponter AA. Estrus synchronization in beef cows: comparison between GnRH+PGF2alpha+GnRH and PRID+PGF2alpha+eCG. Theriogenology. 2003; 60(2):319-330.
Small JA, Colazo MG, Kastelic JP, Mapletoft RJ. Effects of progesterone presynchronization and eCG on pregnancy rates to GnRH-based, timed-AI in beef cattle. Theriogenology. 2009; 71(4):698-706.
Souza AH, Viechnieski S, Lima FA, Silva FF, Araújo R, Bó GA. et al. Effects of equine chorionic gonadotropin and type of ovulatory stimulus in a timed-AI protocol on reproductive responses in dairy cows. Theriogenology. 2009; 72(1):10-21.
Suplicy M, Suplicy Filho H, Kozicki LE, Breda JC, Weiss RR, Segui MS, Reduction of the interval calving-conception by use of hormonal protocols and fixed-time artificial insemination dairy cows. Archives Veterinary Science. 2012; 17:57-62.
Silva RCP, Rodrigues CA, Marques MO, Ayres H, Reis EL, Nichi M. et al. Effect of eCG and GnRH treatments in bos indicus cows submitted to fixed-time artificial insemination. Acta Science Veterinariae. 2004; 32:221.
Azeredo DM, Rocha DC, Jobim MIM, Mattos RC, Gregory RM. Estrous induction and synchronization in beef heifers and their effects on the pregnancy rate and at their performance on the second reproductive season. Ciencia Rural. 2007; 37:201-205.
Downloads
Publicado
Como Citar
Edição
Seção
Licença
Este obra está licenciado com uma Licença Creative Commons Atribuição-NãoComercial 4.0 Internacional.
