Reutilization of autoclaved intravaginal progesterone device for estrous induction and synchronization in Toggenburg goats

This study aimed to evaluate the efficacy of reusing autoclaved intravaginal devices on induction of estrus, ovulation and fertility in Toggenburg goats, besides to measure the plasma progesterone (P4) profile in these animals. The study was performed during the seasonal anestrous period (n=42) and in the breeding season (n=67), at the City of Piau-MG (latitude 21°35 S and longitude 43°15 W). Goats received new intravaginal progesterone devices (CN), or devices used previously during six days (C6) or 12 days (C12) and then autoclaved. Dinoprost (5 mg) latero-vulvar was administered on the day of device insertion and eCG (200 IU) latero-vulvar was done 24 h before its removal. The devices were maintained for six days in all treatments. Ten goats from each treatment were evaluated by transrectal ultrasonography (5 MHz). Blood was collected at different moments for plasma P4 analysis. There was no statistical difference (P>0.05) among the goats of three treatments on the following reproductive parameters observed during the anestrous or breeding season, respectively (average for three treatments): mean estrous induction/synchronization rate (94.9; 76.2%), mean interval from device removal to estrus (33.1 ± 11.4; 37.4 ± 16.2 h), mean duration of estrus (28.6 ± 11.8; 31.7 ± 12.8 h), mean conception rate (61.5; 50.7%), mean ovulating female rate (95.2; 66.7%), mean number of ovulations (1.7 ± 0.7; 1.5 ± 0.6), mean interval from removal to ovulation (68.4 ± 13.0; 77.3 ± 13.8 h), interval from estrus to ovulation (36.6 ± 12.6; 36.7 ± 11.2 h), mean diameter of the dominant follicle (7.4 ± 0.6; 6.7 ± 0.5 mm), co-dominant (6.8 ± 0.6; 6.2 ± 0.1 mm) and medium (7.2 ± 0.6; 6.6 ± 0.4 mm). The small initial concentrations of P4 in alltreatments seven days before device insertion (0.12 ± 0.21) or at the time of insertion (0.23 ± 0.20) may be interpreted as a consequence of reproductive seasonality. Six hours after device insertion CN treatment showed higher (P0,05) entre os três tratamentos nos seguintes parâmetros reprodutivos observados na estação de anestro e de acasalamento natural, respectivamente (valor médio dos três tratamentos): taxa média de indução/sincronização de estro (94,9; 76,2%), intervalo médio da retirada do dispositivo ao estro (33,1 ± 11,4; 37,4 ± 16,2 h), duração média do estro (28,6 ± 11,8; 31,7 ± 12,8 h), taxa média de concepção (61,5; 50,7%), taxa média de fêmeas ovulando (95,2; 66,7%), número médio de ovulações (1,7 ± 0,7;1,5 ± 0,6), intervalo médio da retirada do dispositivo à ovulação (68,4 ± 13,0; 77,3 ± 13,8 h), intervalo médio do início do estro à ovulação (36,6 ± 12,6; 36,7 ± 11,2 h), diâmetro médio do maior folículo (7,4 ± 0,6; 6,7 ± 0,5 mm), segundo maior (6,8 ± 0,6; 6,2 ± 0,1 mm) e médio (7,2 ± 0,6; 6,6 ± 0,4 mm). As baixas concentrações iniciais de P4 em todos os tratamentos sete dias antes da inserção dos dispositivos (0,12 ± 0,21) ou no momento da inserção (0,23 ± 0,20) podem ser interpretadas como reflexo da estacionalidade reprodutiva. Às 6 h após a inserção do dispositivo o tratamento CN apresentou maiores (P