Efficacy Of Different Protocols Of Ovulation Synchronization And Resynchronization In Argentinian Buffalo Herds

During the last years bufalo reproductive researchers have been tried to develop and apply fxed timed artifcial insemination protocols to increase pregnancy rates to maximize improvement. The objective of this paper is to evaluate the pregnancy rates of diferent protocols of synchronization (Ovsynch and progesterone implants) and resynchronization of ovulation in a meat water bufalo herd during reproductive season of 2016. 194 mature Mediterranean females, were randomly assigned to four diferent protocols, ultrasound evaluation were used to determine cyclicity (presence of corpus luteum or follicles ≥7 mm de diameter). 18 days after insemination all females were resynchronized and at day 25 ultrasound were performed, those nonpregnant females were inseminated 28 days after frst insemination. All inseminations were performed by the same technician and only one bull was used. InfoStat software was used, statistical signifcance was considered when p value was lower than α of the 5%. No statistical signifcance were found within the protocols. Early embryonic dead 50 days after IA was 3.4%. Pregnancy rate was 47.9% and 53.5% for insemination and reinsemination respectively and the fnal pregnancy rate after the adjust for early pregnancy loss 73.2%, during the 28 days of the breeding period. The results obtained allow breeders to choose the best pharmacological option to use FTAI in their herds based on their own needs to improve production without afecting pregnancy rates.Fil: Crudeli, Gustavo Angel. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Konrad, José Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: de la Sota, Rodolfo Luzbel. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias; ArgentinaFil: Yuponi, Roberto Gregorio. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Vallejos, Natalia. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Cardona Maya, Walter Darío. Universidad Nacional de Colombia; ColombiaFil: Berdugo, Jesus Alfredo. Universidad de Antioquia; Colombi

Effect of melatonin on follicular development parameters in a fixed-timed artificial insemination programme in water buffalo

It is well known that buffaloes have seasonal anoestrus and that the use of melatonin reduces the effects of season in reproduction, particularly among sheep and goats. This study evaluates the use of melatonin on water buffaloes to increase pregnancy rates in a fixed-time insemination programme. The study was conducted on an Argentinian buffalo herd, located in the Corrientes Province, during an unfavourable reproductive season. Artificial insemination cycles were performed in September and December 2018. Sixty animals were selected, and melatonin was administered to 29 females at a dose of 18 mg/50 kg. Ten days after the melatonin implant, ovulation synchronization was started. Animals were inseminated with frozen semen of a single bull. Pregnancy was evaluated by ultrasound 35 days after insemination. The pregnancy rate of the two repetitions was 34.62% for September and 6.4% for December (P=0.007). No significant differences were found in the parameters associated with follicular development and formation of the corpus luteum. Analysis of the effects of melatonin on the two replicates showed that there was no statistically significant effect of ovarian response regarding the analysed follicular development parameters. There was also no effect on pregnancy rates (17.85% vs. 20.68%; P=0.15), or on follicular development for treatment and control. In conclusion, this study was not able to demonstrate an effect of melatonin on the ovarian response of buffaloes as reported by other authors. Other factors, such as environmental conditions of subtropical areas and species specificities, may have a more significant effect on buffalo endocrinology. These factors should be evaluated to improve the results of fixedtimed artificial insemination programmes.Fil: Berdugo, Jesus Alfredo. Universidad Nacional de Colombia; ColombiaFil: Konrad, José Luis. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Yuponi, Roberto Gregorio. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Bandeo, Alexis Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Camelino, Ramon. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Cardona Maya, Walter D.. Universidad de Antioquia; ColombiaFil: Crudeli, Gustavo Angel. Universidad Nacional del Chaco Austral; Argentin