Pre-TAI protocol strategies to increase reproductive efficiency in beef and dairy cows

Ovulation synchronization protocols are well established in beef and dairy cows. However, the protocol response rate is around 70-90%. In beef cows, factors such as inadequate nutrition and calf presence negatively impact the response of progesterone (P4)/estradiol-based ovulation synchronization protocols by interfering with GnRH release and consequently reducing LH pulsatility and final follicular development. In dairy cows, protocols based on GnRH and prostaglandin (Ovsynch) are the most widely used in the world. However, the efficiency of Ovsynch is dependent on the presence of a large follicle at the time of administration of the first GnRH. In these ovulation synchronization protocols, pre-synchronization protocols (Prostaglandins, Double Ovsynch and P4synch) are usually attempted in an effort to increase responses. Thus, the objective of this review was to discuss pre-ovulation synchronization strategies (administration of injectable P4 or energetic/protein supplementation or presynchronization with intra-vaginal progesterone devices) aiming to increase the LH pulsatility in beef cows or induce the formation of a GnRH-responsive follicle at the beginning of the Ovsynch protocol in dairy cows.

Pre-TAI protocol strategies to increase reproductive efficiency in beef and dairy cows

Ovulation synchronization protocols are well established in beef and dairy cows. However, the protocol response rate is around 70-90%. In beef cows, factors such as inadequate nutrition and calf presence negatively impact the response of progesterone (P4)/estradiol-based ovulation synchronization protocols by interfering with GnRH release and consequently reducing LH pulsatility and final follicular development. In dairy cows, protocols based on GnRH and prostaglandin (Ovsynch) are the most widely used in the world. However, the efficiency of Ovsynch is dependent on the presence of a large follicle at the time of administration of the first GnRH. In these ovulation synchronization protocols, pre-synchronization protocols (Prostaglandins, Double Ovsynch and P4synch) are usually attempted in an effort to increase responses. Thus, the objective of this review was to discuss pre-ovulation synchronization strategies (administration of injectable P4 or energetic/protein supplementation or presynchronization with intra-vaginal progesterone devices) aiming to increase the LH pulsatility in beef cows or induce the formation of a GnRH-responsive follicle at the beginning of the Ovsynch protocol in dairy cows.(AU)

Exame ginecológico e acompanhamento reprodutivo em éguas / Gynecological examination and monitoring reproductive in mares

O exame ginecológico na espécie equina é de extrema importância para aumentar a eficiência reprodutiva dos animais, aproveitar suas características desejáveis e intensificar o melhoramento genético. Porém, a influência do fotoperíodo acarreta variações na incidência das ovulações nas éguas durante o decorrer do ano. Assim, o acompanhamento reprodutivo para predição da ovulação, utilização de hormônios ebiotecnologias torna-se essencial. Este trabalho aborda aspectos morfológicos dos órgãos genitais, aspectos da fisiologia reprodutiva e dinâmica folicular de éguas.

The gynecological examination in the equine species has an extreme importance to increase the reproductive efficiency of the animals, take the advantage of its desirable characteristics and intensify the genetic improvement. However, an influence of the photoperiod causes variations in the incidence of ovulation in the mares during the course of the year. Thus, reproductive monitoring for ovulation prediction, use of hormones and biotechnologies becomes essential. This work deals with themorphological aspects of the genital organs, the reproductive physiology and the follicular dynamics of mares.