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Objective. To determine the influence of corporal composition at delivery (CCD) on the ovarian postpartum restart (OPR) of the Holstein cow in the Andes Region in Ecuador. Materials and methods. 30 cows were produced. All of the following moments were determined: the appearing of the dominant follicle (DF), the ovulation and luteal activity; the duration of the estrous cycle, the volume of the luteum body (LC) and the progesterone concentrations (P4) on blood serum. Descriptive statisticians of the OPR variables and its indicators were compared according to the BC, by means of a t-Student test for independent samples. The relationship between the BC and the postpartum OPR through a case-control case was assessed. Results. The duration of the oestrous cycle was 23.10 days, 46.67% of the cows had regular cycles and 53.33% were abnormal cycles. The DF, the ovulation and the luteal activity were seen at 16.63, 27.76 and 41.38 after postpartum, respectively; before (p, Objetivo. Determinar la influencia de la condición corporal al parto (CCP) en el reinicio de la actividad ovárica (RAO) posparto de la vaca Holstein en la región andina de Ecuador. Materiales y métodos. Se trabajaron 30 vacas. Se determinaron el momento de aparición del folículo dominante (FD), de ovulación y de actividad luteal; la duración del ciclo estral, el volumen del cuerpo lúteo (CL) y las concentraciones de progesterona (P4) en suero sangíneo. Los estadígrafos descriptivos de las variables del RAO y sus indicadores se compararon según la CCP mediante una prueba de t-Student para muestras independientes. Se evaluó la asociación entre la CCP y el RAO posparto mediante un estudio caso control. Resultados. La duración del ciclo estral fue 23.10 días, el 46.67% de las vacas tuvo ciclos normales y el 53.33% ciclos anormales. El FD, la ovulación y la actividad luteal ocurrieron a los 16.63, 27.76 y 41.38 días posparto, respectivamente; antes (p

Tesis - Universidad CEU Cardenal Herrera (Valencia), Facultad de Veterinaria, Departamento de Medicina y Cirugía Animal, leída el 14-07-2017.

Tesis - Universidad CEU Cardenal Herrera (Valencia), Facultad de Veterinaria, Departamento de Medicina y Cirugía Animal, leída el 15-09-2016. Los folículos hemorrágicos anovulatorios (HAF) son la patología anovulatoria más común en yeguas. Dicha condición es comparable a la que padecen las mujeres (folículos luteinizados anovulatorios), siendo una causa importante de infertilidad en medicina humana. La causa exacta por la que se producen estos folículos es todavía una incógnita, pero son muchos los factores que influyen en la inhibición de la ruptura folicular. Estudios en yeguas y en otras especies han demostrado que la inhibición de la síntesis de prostaglandinas (PG) mediante administración de antiinflamatorios no esteroideos (AINEs) en el periodo periovulatorio ha producido un alto porcentaje de folículos luteinizados anovulatorios. De forma fisiológica es la hormona luteinizante (LH) la que inicia la cascada de eventos que tienen como fin la ovulación, entre los cuales está la síntesis de PG dentro del folículo preovulatorio. Otro elemento que parece estar implicado en la formación de HAF son los niveles altos de prolactina como se ha demostrado en otras especies como la rata y el conejo. Un estudio reciente obtuvo resultados similares de producción de folículos luteinizados anovulatorios en yeguas mediante la administración de sulpirida, un antagonista de la dopamina que eleva la prolactina. El objetivo de esta tesis doctoral fue valorar el efecto de la prolactina y las prostaglandinas E2 y F2α sobre la ovulación y fertilidad en la yegua. La administración de sulpirida durante el periodo periovulatorio produjo un aumento de las concentraciones plasmáticas de prolactina. Sin embargo, esta hiperprolactinemia no tuvo ningún efecto sobre la ovulación ni sobre la formación de folículos hemorrágicos anovulatorios. En yeguas tratadas con AINEs en el periodo periovulatorio, la administración intrafolicular de PGE2 y PGF2α restableció la ovulación dentro de las 12 h tras la inyección, evitando la formación de folículos luteinizados anovulatorios. Además, supuso la correcta liberación y fertilización del ovocito, ya que las yeguas quedaron gestantes. Este mismo protocolo se empleó en yeguas al inicio del estro. En la mayoría de las yeguas se produjo el colapso folicular dentro de las 12 h siguientes a la administración del tratamiento. Esta fase del estudio reafirma el papel de las prostaglandinas en el proceso de ruptura de la pared y colapso folicular y sugiere que este hecho puede suceder incluso antes de la última fase de la onda preovulatoria de LH.

The mare is a seasonally polyestrus breeder. In early spring, the mare enters a "transition period" between the anovulatory season and the first ovulation of the year. This period is characterized by irregular estrus cycles and high incidence of regressing dominant follicles. There is a belief that pregnancy rates resulting from the first ovulation of the season is lower than in subsequent ovulations, however this has never been studied critically. Progestagens are often used as an aid to manage the transition period. The objective of this study was to compare pregnancy rates of mares from the first ovulation of the year with: (a) mares on their second or subsequent ovulations and (b) mares with progesterone-primed first ovulations. A total of 136 thoroughbred mares were used in the study. The mares were classified into four groups: (1) mares mated at the first ovulation of the year (n=46); (2) mares mated in the first ovulation of the year after removal of a previously inserted progesterone device (CIDR) (n=29); (3) mares mated at the second or more ovulations of the year after prostaglandin-induced estrus (n=50); and (4) mares mated after spontaneous return to estrus (n=11). Pregnancy rates were not different in any of the groups studied: 65.2, 75.9, 76 and 72.7 for groups 1-4 respectively (P>0.05). Group 1 mares had the lowest response to hCG treatment which resulted in the highest number of services per cycle (P

Luteolysis is a key event in cattle reproduction. A standard dose of exogenous PGF(2α) will induce full luteolysis in the majority of cows with a matured corpus luteum (CL). However, this will not occur in cows with a CL

Early embryonic loss (EEL) negatively affects the reproductive efficiency of equine reproduction. A sign of future EEL is when the embryo proper (EP) fails to develop within the embryonic vesicle after 30 days of gestation. The earlier the identification of impending EEL, the earlier the mare can be rebred to allow a second chance of pregnancy. The objectives of this study were to determine the percentage of embryonic vesicles with a visible EP at 18-28 days of gestation and to study the association between the presence/absence of the EP at different days of gestation and the future viability of the pregnancy. A total of 1,256 pregnancies were identified and followed by transrectal B-mode ultrasonography 12-45 days post ovulation in mares of the same Thoroughbred farm. The identification of the EP was attempted once during days 18-28. Pregnancy reconfirmation was performed on days 35-45. The percentage of vesicles with an EP increased gradually from days 18 (2.8%) to 21 (86.9%) (P 71%) on day 20 of gestation. The lack of a positive identification of an EP from day 20 onward is associated with a higher EEL rate.

The development of hemorrhagic anovulatory follicles (HAF) involves luteinization and hemorrhage of the follicle. This is observed on ultrasound as an increase in the echogenicity of the granulosa layer and formation of echoic particles in the antrum. The inhibition of prostaglandin synthesis with flunixin meglumine (FM) during the periovulatory period induces ovulatory failure with development of luteinized unruptured follicles (LUF). These two types of anovulatory follicles appear to share similar ultrasound features but they have not been compared critically. The following endpoints: follicle diameter, follicular contents score, interval from hCG administration to beginning of follicular hemorrhage, interval from hemorrhage to organization of follicular contents, and cycle length were studied and compared in mares with HAF (n = 11) and LUF (n = 13). The objective of this study was to elucidate whether these two unruptured follicles have a consistent clinical pattern of development and therefore can be considered as part of the same anovulatory syndrome. None of the endpoints analyzed differed significantly between HAF and LUF. However, there was a greater individual variation in HAF as compared with LUF in regards to interval from hCG to hemorrhage, follicular diameter at the administration of hCG, and beginning of hemorrhage. In conclusion, HAF share a similar cascade of ultrasound characteristics with the experimentally induced LUF. This finding may provide new insights in elucidating the pathogenesis of HAF.

The association between use of hormone treatments to induce estrus and ovulation and the incidence of hemorrhagic anovulatory follicles (HAFs) was studied in a mixed population of mares (Equus caballus) during two breeding seasons in a commercial breeding clinic. Mares treated with cloprostenol (CLO) were more likely to develop HAFs than were mares with spontaneous cycles (P0.001) or those treated with human chorionic gonadotropin alone (P=0.08). There was no significant effect of season on the incidence of HAFs. The mean (+/-SEM) interval from CLO treatment to beginning of HAF development was 6.1+/-0.5 d. Age of mares with HAF cycles was not different (12+/-1.3 yr; P0.05) from that of mares with ovulatory cycles (10.5+/-1.5 yr).

Reproductive records of the entire lives of two mares with abnormally high incidence of multiple ovulation and hemorrhagic anovulatory follicles were analyzed retrospectively. Chi-square analysis was used to test statistically the effect of cloprostenol, a prostaglandin F2 analog, on the incidence of multiple ovulations, hemorrhagic anovulatory follicles, and its ultrasonographic appearance. A total of 319 estrous cycles during a 17-year period were analyzed. Cycles induced with cloprostenol were more likely ( P

Although the ovulatory effects of prostaglandins are well documented in several domestic species including horses, there has been little attention paid to the use of this ovulatory effect for clinical purposes. Mares often grow large follicles during the luteal phase that may or may not ovulate before progesterone levels decline. Clinical observations of administering prostaglandins in disestrous mares with large follicles suggest that there may be a negative correlation between follicular diameter and interval from treatment to ovulation. The objectives of this study were twofold: to investigate the cloprostenol dose rate effect on interval to ovulation and to confirm the negative correlation between follicular diameter and interval to ovulation. The hypothesis tested was that high doses of cloprostenol given in diestrous to mares with larger follicles would induce ovulation more rapidly than in mares given lower doses or with smaller follicles. To test the hypothesis, a total of 1,234 estrous cycles were induced with different doses of cloprostenol (ranging from 8.75 to 625 mu g). All mares had at least one follicle of 28 mm or larger. Dominant follicles were followed by transrectal ultrasound examinations every other day until ovulation was detected. There was a significant effect of dose (P < .000) and follicular diameter (P < .000) on the interval from treatment to ovulation. The shortest mean interval (2.4 days) was observed after administration of 625 mu g in mares with follicles 36mm or larger, whereas the longest (4.9 days) occurred after 8.75 mu g in follicles to 28 to 31 mm.

Embryonic vesicle growth in the mare is easily monitored by ultrasound. Apart from pregnancy diagnosis, assessment of the embryonic vesicle in practice is also useful to evaluate its viability. Although subject to individual variation, embryo growth rate follows a constant pattern in the early stages of development in relation to embryonic age. Previous studies have shown a significant effect of some factors routinely used in practice, such as post-ovulation insemination and embryo transfer, on embryonic growth and the time in which the vesicle is first detected. This study attempts to confirm previous results in different settings and characterise the causes for this delay in growth. A total of 159 pregnancies from different mating protocols: (1) pre-ovulation natural mating, (2) pre-ovulation natural mating and transfer into recipient mares, (3) post-ovulation natural mating, and (4) post-ovulation AI with frozen/thaw spermatozoa were evaluated ultrasonographically from day 12 to 19 of pregnancy and vesicle diameters recorded. Regression analysis between embryonic vesicle diameters and embryonic ages was performed for each group and mean vesicle diameter at different age periods among groups were tested for statistical difference with a general linear model of variance. There was no significant difference between groups 1 and 2 (P=0.73) or between groups 3 and 4 (P=0.71). However both pre-ovulation groups (1 and 2) had larger vesicle diameters (P

Follicular diameter is used as a guiding tool to predict ovulation in the mare. However, the great range in preovulatory follicular diameter makes prediction of optimal breeding time based on follicular diameter unreliable. Uterine edema pattern is also useful to determine the best time to breed, since intensity of edema tends to dissipate as ovulation approaches, however, not every mare follows this pattern. The aims of this study were to assess the repeatability of preovulatory follicular diameter and uterine edema pattern in two consecutive spontaneous cycles and to determine how induction treatments (hCG, PGF(2)alpha and GnRH analogues) influence them. Fifty-three mares were followed during two consecutive cycles and scanned three times a day from 2 to 3 days before ovulation. During the first cycle, mares had a spontaneous ovulation and in the consecutive cycle mares received either: (a) no hormonal treatment; (b) 1500 IU hCG; (c) 125-250 microg Cloprostenol or (d) 2.1 mg Deslorelin implant. Mares ovulated consistently from similar follicular diameters in two consecutive spontaneous cycles (r=0.89; P

Se seleccionaron 64 llamas hembras sin cría al pie y en condiciones reproductivas óptimas. El criterio de selección se basó en la presencia de un folículo dominante ³7mm, detectado por ecografía transrectal.Alas hembras seleccionadas se les aplicó 5mg deLH (LutropinV) para realizar una sincronización de la emergencia de una nueva onda folicular, confirmándose 12 días después la presencia de un nuevo folículo dominante (³7 mm). Los animales fueron entonces distribuidos al azar en cuatro grupos. Alos primeros tres grupos se les inyectó 2 ml vía i.m. de plasma seminal de llama, alpaca y toro, y al cuarto grupo (control) se le aplicó PBS (suero básico fosfatado). La ocurrencia de ovulación se evaluó dos días después, encontrándose que las tratadas con plasma seminal de llamas y alpacas tuvieron una tasa de ovulación del 100%, las tratadas con plasma seminal de toro de 25% y ninguna en el grupo control. Al noveno día post tratamiento se midió el tamaño del cuerpo lúteo, encontrándose que no existe diferencia significativa entre los grupos tratados. En base a los resultados se puede señalar que la administración intramuscular de plasma seminal de llama, alpaca y en menor grado de toro, induce la ovulación en las llamas hembras y favorece la formación de un cuerpo lúteo de características propias de la especie., Female llama without calf at foot, in good reproductive conditions and bearing a follicle ³7 mm in the ovaries, detected by ultrasonography, were selected (n = 64). All animals were administered 5 mg of LH(Lutropin V) to synchronize the newly emergent follicular wave.Asecond ultrasonography evaluation was done 12 days later to confirm the presence of a dominant follicle (³7mm) and then, animalswere randomlydistributed into four groups. The first three groups were i.m. injected (2 ml)with llama, alpaca and bull seminal plasma, respectively, and the fourth group was injected with PBS (phosphate basic serum) and remained as control. The occurrence of ovulation was evaluated two days later.All animals injectedwith llama and alpaca seminal plasma ovulated, whereas only 25% of llamas treated with bull seminal plasma, and none of the control group ovulated. The size of the corpus luteum 9 days after treatment did not vary among the treated groups. The results indicated that the i.m. administration of llama and alpaca seminal plasma, and in lesser degree, the bull seminal plasma induce ovulation in the llama and allow the growth of a corpus luteum to a size proper of these species.