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Abstracts. II International Symposium on Animal Biology of Reproduction, Nov. 19-22, 2008, São Paulo, SP, Brazil. Estrous and ovulation rate after synchronization of nulliparous Anglo-nubian goats treated with increasing insulin doses E.S.P. Pinheiro, A.L. Souza, K.C. Almeida, A.C.L. Câmara, I.J. Arruda, I.M.T. Lima, V.J.F. Freitas, D.I.A Teixeira, D. Rondina Programa de Pós-Graduação em Ciências Veterinárias, Faculdade de Veterinária, Universidade Estadual do Ceará, Fortaleza, Ceará. 60740-000, Brasil. Introduction The lower reproductive response of nulliparous at first mating is a recognized limiting factor of goat husbandry. Several studies showed in adult goats that insulin administration can have a positive action on ovarian function, increasing numbers of recruited follicles and ovulation rate (1, 2). However, these studies did not appointed any evidence about the reproductive response to insulin administration in young animals. Thus, the aim of this work was to compare the response of estrous synchronization and ovulation rate in nulliparous Anglonubian goats treated with increasing insulin doses. Materials and Methods The experiment was conducted in Tauá-CE (6, 0°S and 40, 4°W). Fifteen Anglo-nubian nulliparous goats with live weight of 26.60 ± 4.70 kg (mean ± SEM) and aged between 8 and 15 months has their estrous synchronized with 60 mg MPA vaginal sponge for 10 days and 50 µg of cloprostenol on 8 th day. Goats were allocated in three groups: Insulin I (n = 5), Insulin II (n = 5) and Control (n = 5). In Insulin I and II groups, all animals were treated subcutaneously with 0.14 IU/kg BW/day and 0.2 IU/kg BW/day human long acting insulin, respectively, during three consecutive days beginning 48h before sponge removal. In control group saline solution was administrated. The goats were monitored three times a day (06:00, 12:00 and 18:00 hours) for the occurrence of estrous and mated at onset of estrous and again 24 h later, using three Anglonubian bucks of confirmed fertility. Ovulation rate was recorded 3 days after mating, using a Falco 100 ultrasound scanner (Pie Medical ® , Maastricht, Netherlands) fitted to 6/8 MHz linear-array probe. The insulin effect was analyzed by the SAS GLM procedure. Comparison between groups was performed by the Duncan test. Values were expressed as mean ± SEM. Results and Discussion All goats showed estrus after synchronization treatment. Estrus length, the interval between sponge removal and estrus onset as well as ovulation did not differ between groups (P < 0.05), with a pooled mean, respectively of 37.80 ± 1.93; 28.67 ± 2.12; 59.80 ± 2.18 hours. These data are in agreement with (1). Higher induction of estrous has been reported in insulin-treated anestrous cattle (3) and goat (2), suggesting an insulin effect on steroidogenesis. Ovulation rate was significantly (P < 0.05) higher in the Insulin I than in the Control group (2.6 ± 0.51 vs. 1.0 ± 0.2; P < 0.01), while in Insulin II group was similar to other treatments (1.6 ± 0.4). Similar findings in goats treated with insulin prior superovulation have been reported (1). The positive effect of insulin on ovarian response in low dose insulin group should be due to either an increase of gonadotrophin-dependent follicles number (4) as well as reduction of follicular atresia (5). Based on our results, we can conclude that treatment with increasing insulin doses in nulliparous goats did not affect the response to estrous synchronization; however the administration of 0.14 IU/kg BW/day produced a higher ovulation rate. References (1) Selvaraju S, Agarwal SK, Karche SD, Majumdar AC. 2003. Theriogenology, 59:1459-1468; (2) Sarath T, Mehrotra S, Agarwal SK, Varshney VP, Hoque M, Shankar U, Singh SK. 2008. Anim Reprod Sci, 108:216-225; (3) Shukla SN, Agarwal SK, Shankar U, Varshney VP, Majumdar AC. 2005. Indian J Anim Sci, 75:1135-1139; (4) Gong JG, Webb R. 1996. Anim Breed Abstr, 64:195-204; (5) Matamoros IA, Cox NM, Moore AB.1991. J Anim Sci, 69:2081-2091. E-mail: beth_saraiva@yahoo.com.br Anim. Reprod., v.6, n.1, p.225, Jan./Mar. 2009 225
226 Abstracts. II International Symposium on Animal Biology of Reproduction, Nov. 19-22, 2008, São Paulo, SP, Brazil. Preovulatory follicle dynamics in Toggenburg goats after treatment with intravaginal implants of progesterone for 6, 9 or 12 days P.M.P. Nascimento 1 , F.Z. Brandão 1 , P.F.V. Pereira 1 , A.P. Oliveria 2 , J.H.M. Viana 3 , J.F. Fonseca 4 1 Universidade Federal Fluminense, Niterói - 24.230-340, RJ; 2 EPAMIG, Belo Horizonte, MG ; 3 Embrapa Dairy Catlle, Juiz de Fora, MG; 4 Embrapa Goats, Sobral, CE, Brasil. Introduction The use of ultrasound in reproduction made the daily monitoring of ovarian follicular development during estrous cycle possible, demonstrating the growth and regression patterns of antral follicles, and allowed a clear understanding of the process of recruitment, selection and follicular dominance in cattle (1,3) and sheep (2). The aim of this study was to evaluate the preovulatory follicular dynamics in goats, after hormone treatment at the anoestrus period for the induction and synchronization of estrus. Material and Methods Nulliparous and pluriparous (lactating or not) Toggenburg goats, with mean weight of 47.37 ± 1.75 and 3.65 ± 0.15 of body score condition (1 to 5 range), were selected and equally distributed into three groups: Treatment 1 (n = 10); treatment 2 (n = 10) and treatment 3 (n = 10). The animals remained with the intravaginal progesterone device (CIDR ®, Pfizer - New Zealand) for 6, 9 or 12 days, respectively. At the moment of insertion of the device they received 1ml of prostaglandin (Lutalyse®, Pharmacia Corporation-USA) paravulvar and 24 hours before the device withdrawal 200U.I. (IM) equine chorionic gonadotropin (Novormon®, Syntex – Argentina) was given. The preovulatory dynamics was monitored using a portable ultrasound device equipped with an adapted 5 MHz probe, at 8-hour intervals (08:00 a.m., 04:00 p.m. and 00:00 a.m.) from the moment of CIDR withdrawal until the confirmation of ovulation. The position and number of ovarian follicles were recorded, and the diameter of antral follicles larger than 3.0 mm measured. Data from each animal was recorded on individual cards. Results and Discussion There was a higher incidence of ovulations in the right ovary in all treatments. The 9 day treatment presented larger (p < 0.05) follicles at the moment of the CIDR withdrawal. As the follicle growth rate, follicle size at ovulation and number of ovulations were similar among treatments (p > 0.05), the difference in dominant follicle size at CIDR withdrawal resulted in a shorter interval to ovulation in the 9 day treatment. This difference may be related to the moment of the follicle emergence when the insertion of the device, and also the follicle turnover period in goats (Table 1). Table 1. Preovulatory follicle dynamic characteristics in each treatment. Parameter Treatment 12 days 9 days 6 days Follicular diameter at the time CIDR withdrawal (mm) 5.6 ± 0.9 a 6.7 ± 0.88 b 5.6 ± 0.7 a Follicular diameter at the time ovulation (mm) 7.1 ± 0.6 a 7.2 ± 0.56 a 6.7 ± 0.6 a Interval CIDR withdrawal – ovulation (h) 37.1 ± 9.3 a 21.9 ± 5.8 b 38.5 ± 8.3 a Growth follicular rate (mm/day) 1.0 ± 0.5 a 0.5 ± 0.9 a 0.7 ± 0.5 a % of ovulation in right ovary 64.0 a 62.0 a 69.0 a Total of ovulations 1.8 ± 0.9 a 1.3 ± 0.5 a 1.6 ± 0.5 a a,b Means followed by different letters, in the same line, differ (p < 0.05). References (1) Coutinho GTRM, Viana JHM, Sá WF, et al. 2007. Avaliação ultra-sonográfica da dinâmica folicular e lútea em vacas da raça Guzerá. Arq Bras Med Vet Zootec, 59:1089-1096; (2) Evans ACO, Duffy P, Hynes N, et al. 2000. Waves of follicle development during the estrus cycle in sheep. Theriogenology, 53:699-715; (3) Ginther OJ, Wiltbank MC, Friche PM, et al. 1996. Selection of the dominant follicle in cattle. Biol Reprod, 55:1187-1194. E-mail: paulampn@gmail.com Anim. Reprod., v.6, n.1, p.226, Jan./Mar. 2009
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