Abstract The objective of this work was to evaluate the effect of the interaction between feeding level (FL) and body condition score (BCS) on the reproductive parameters of Pelibuey hair sheep (Ovis aries). The experimental units (64 ewes) were randomly assigned to one of four treatments: low feeding level and low body condition score; high feeding level and low body condition score; low feeding level and high body condition score; and high feeding level and high body condition score. The effect of sheep body condition score was significant on the pregnancy and lambing rates. The effect of feeding level was significant on the ovulation, estrus returning, pregnancy, and prolificacy rates. The interaction effect between BCS and FL was significant on the ovulation, estrus returning, pregnancy, lambing, and prolificacy rates. The reproductive function is more sensitive to the better nutrition effects in sheep with a low body condition score.

Resumo O objetivo deste trabalho foi avaliar o efeito da interação entre nível de alimentação (FL) e escore de condição corporal (BCS) sobre os parâmetros reprodutivos de ovelhas de pelo Pelibuey (Ovis aries). As unidades experimentais (64 ovelhas) foram distribuídas aleatoriamente a um dos quatro tratamentos: baixo nível de alimentação e baixo escore de condição corporal; alto nível de alimentação e baixo escore nas condições corporais; baixo nível de alimentação e alto escore nas condições corporais; e alto nível de alimentação e alto escore nas condições corporais. O efeito do escore de condição corporal de ovelhas foi significativo sobre as taxas de prenhez e parto. O efeito do nível de alimentação foi significativo sobre as taxas de ovulação, retorno do estro, prenhez e prolificidade. O efeito da interação entre escore de condição corporal e nível de alimentação foi significativo sobre as taxas de ovulação, retorno do estro, prenhez, parto e prolificidade. A função reprodutiva é mais sensível aos melhores efeitos nutricionais em ovelhas com baixo escore de condição corporal.

Abstract The objective of this work was to determine the nutritional content and the degradability of the dry matter and protein of fruits of Chloroleucon mangense and Acacia cochliacantha and of a 1:1 mixture of both, offered as supplements to Rambouillet sheep. In situ ruminal degradation was evaluated in three adult rams, fitted with a rumen cannula, with different incubation times of 0, 6, 12, 24, 48, and 72 hours. Protein intestinal degradability was quantified with a three-step procedure: in situ ruminal incubation, in vitro enzymatic digestion, and abomasal-intestinal digestion. The fruits of C. mangense and A. cochliacantha contain 21 and 12% crude protein, 47 and 56% neutral detergent fiber, 31 and 43% acid detergent fiber, and 0.9 and 6.0% condensed tannins, respectively. The fruits of C. mangense showed a higher nutritional value and a higher dry matter and crude protein degradability (p<0.05) than those of A. cochliacantha and the 1:1 mixture. The amount of protein that reaches the small intestine is higher for the 1:1, which is an indicative that its tannin concentration is enough to increase the bypass protein that can be absorbed in the small intestine.

Resumo O objetivo deste trabalho foi determinar o conteúdo nutricional e a degradabilidade da matéria seca e da proteína de frutos de Cloroleucon mangense e Acacia cochliacantha e de uma mistura 1:1 de ambos, oferecidos como suplementos para carneiros Rambouillet. Foi avaliada a degradação ruminal in situ em três carneiros adultos, com colocação de uma cânula ruminal, com diferentes tempos de incubação de 0, 6, 12, 24, 48 e 72 horas. A degradação intestinal da proteína foi quantificada por meio de procedimento com três etapas: incubação ruminal in situ, digestão enzimática in vitro e digestão abomasal intestinal. Os frutos de C. mangense e A. cochliacantha contêm 21% e 12% de proteína bruta, 47% e 56% de fibra em detergente neutro, 31 e 43% de fibra em detergente ácido e 0,9 e 6,0% de taninos condensados, respectivamente. Os frutos de C. mangense apresentaram valor nutricional edegradabilidade da matéria seca e da proteína bruta (p<0,05) maiores que os de A. cochliacantha e da mistura 1:1. A quantidade de proteína que chega ao intestino delgado é maior para a mistura 1:1, o que é indicativo de que sua concentração de tanino é suficiente para aumentar a proteína não degradável no rúmen absorvida no intestino delgado.

Resumen La inducción de la lactancia en el ganado es una forma alternativa de aumentar la vida productiva de las vacas con problemas reproductivos y productivos que, de lo contrario, serían sacrificadas. Se propone un protocolo alternativo de inducción de la lactancia. En este protocolo de 21 días se aprovecha la producción de progesterona endógena y utiliza dosis bajas de estradiol para estimular el crecimiento y la función de la ubre. Se inyectaron 500 mg de somatotropina en los días uno, ocho, catorce y veintiuno a vacas (n= 5) y vaquillas (n= 4) Holstein. Se aplicó el benzoato de estradiol (3-10 mg día-1) desde el día uno hasta el día catorce. A los animales se les administró cloprostenol (500 µg) en la mañana y en la tarde del día 1, y del día 18 al 21 se les inyectó dexametasona (5 mg día-1). Se ordeñaron a las vacas y vaquillas por primera vez el día 22. No se administró progesterona exógena en ningún momento del experimento, pero el protocolo de lactancia comenzó en la fase diestro del ciclo de celo y se inyectó GnRH para inducir la formación de un cuerpo lúteo accesorio. La inducción de la lactancia fue exitosa en todos los animales y la producción de leche varió de 18.3 a 25.5 kg día-1. La producción endógena de progesterona en combinación con dosis reducidas de benzoato de estradiol es suficiente para inducir la lactancia en vacas Holstein.

Abstract Lactation induction in cattle is an alternative way to increase the life span of cows with reproductive and productive issues that would otherwise be culled. An alternative lactation induction protocol is proposed. This 21-d protocol takes advantage of endogenous progesterone production and uses low doses of estradiol to stimulate udder growth and function. Holstein cows (n= 5) and heifers (n= 4) were injected with 500 mg of somatotropin on days one, eight, fourteen, and twenty-one. Estradiol benzoate (3-10 mg d-1) was applied from day one to fourteen. Cloprostenol (500 µg) was administered to the animals am and pm on d 1, and from d 18 to 21, they were injected dexamethasone (5 mg d-1). The cows and heifers were milked for the first time on d 22. Exogenous progesterone was not supplemented, but lactation protocol began in the diestrus phase of the estrous cycle and GnRH was injected to induce formation of an accessory corpus luteum. Lactation induction was successful in all animals, milk production ranged from 18.3 to 25.5 kg d-1. In conclusion, endogenous progesterone production in combination with reduced doses of estradiol benzoate is sufficient to induce lactation in Holstein cattle.

ABSTRACT 34 Alpine goats were used with the objective of evaluating the effect of energy density in the diet, on the return to postpartum ovarian activity. Three experimental groups were formed: E80: 80% of the postpartum energy requirements, E100: 100% of the requirements and E120: 120% of the requirements. The diet was provided 3 weeks before and up to 60 days after delivery. Female weight was determined every five days and the ovaries were scanned by ultrasonography twice a week to assess follicular growth. The day the females ovulated was determined by radioimmunoassay, based on the progesterone concentration. The goats in E120, observed higher weights than in E80 and E100 (P≤0.05). In E100 the first follicle presented earlier (27.09 ± 08.5 days; P≤0.05) and presented the highest percentage of ovulation (54.54%). There were no differences in the calving-ovulation interval between E100 and E120 (P <0.05). The level of energy consumption in the diet stimulates postpartum ovarian activity; however, a low percentage of animals ovulate, which may indicate that there are other factors that can condition the complete recovery of the ovary, such as suckling.

RESUMEN Se utilizaron 34 cabras Alpinas con el objetivo de evaluar el efecto de la densidad de energía en la dieta, en el retorno a la actividad ovárica postparto. Se conformaron tres grupos: E80: 80% de los requerimientos de energía en postparto, E100:100% de los requerimientos y E120: 120% de los requerimientos. La dieta se proporcionó 3 semanas antes y hasta 60 días después del parto. Se determinó el peso de las hembras cada cinco días y se escanearon los ovarios por ultrasonografía dos veces por semana, para evaluar el crecimiento folicular. Por medio de Radioinmunoanálisis se determinó el día en que las hembras ovularon, con base en la concentración de progesterona. Las cabras en E120, observaron pesos más altos que en E80 y E100 (P≤0.05). En E100 el primer folículo se presentó más temprano (27.09±08.5 días; P≤0.05) y presentó el mayor porcentaje de ovulación (54.54%). No hubo diferencias en el intervalo parto-ovulación entre E100 y E120 (P<0.05). El nivel de consumo de energía en la dieta estimula la actividad ovárica postparto; sin embargo, un bajo porcentaje de animales ovulan lo que puede indicar que hay otros factores que pueden condicionar la recuperación completa del ovario como el amamantamiento.

Abstract Mycobacterium avium subsp. paratuberculosis (MAP) is the causative agent of paratuberculosis (PTB), disease that causes a syndrome of bad nutrient absorption, weight loss and eventually death. The intestine is the main target organ where the infection develops; however, there is evidence of infection by MAP in extra-intestine sites of sheep, including mesenteric nodes and semen. The aim of the study was to identify the presence of MAP in reproductive tissue and semen of infected Pelibuey rams in clinical state of PTB. Seven rams were used in clinical PTB state and a non-infected ram by MAP of the Pelibuey breed, confirmed by serology, nPCR and bacteriological culture, with average weight and age of 57.23 ± 1.73 kg and 2.91 ± 0.17 years, respectively. The presence of MAP was identified in different tissue samples: spleen (1/7, 14.3% and 2/7, 28.6%), small intestine (3/7, 42.9% and 4/7, 57.1%) and mesenteric lymph nodes (3/7, 42.9% and 3/7, 42.9%), with nPCR and culture, respectively. It was also identified in epididymis tissue (1/7, 14.3%), Cowper gland (2/7, 28.6%) and prostate (1/7, 14.3%), using nPCR, although without detection in culture. It was identified in testicular tissue in 42.8% (3/7; culture or nPCR technique), but in 28.6% (2/7) with both techniques. Finally, the presence of MAP was identified in 42.9% (3/7) of semen samples with nPCR; however, it was not detected through culture. In conclusion, the presence of MAP was identified in lymphatic, digestive tissue, and semen; the presence of MAP was reported for the first time in epididymis, Cowper gland, prostate and testicles of infected Pelibuey rams.

Resumo: O objetivo deste trabalho foi avaliar o efeito da somatotropina bovina recombinante (rBST) e do reconstituinte metabólico Metabolase (MR) no reestabelecimento da atividade ovariana pós-parto de ovelhas Pelibuey. Noventa e quatro ovelhas, com seus respectivos cordeiros, foram distribuídas ao acaso a um dos seguintes tratamentos: T1, amamentação continua (AC); T2, AC + MR; T3, AC + rBST; e T4, AC + MR + rBST. Foram avaliados percentagem de ovulação, alterações de peso em ovelhas e carneiros, incidência do estro, início e retorno ao estro, parição, fecundidade e prolificidade. As maiores percentagens de ovulação foram registradas para AC em T1 e T2, e as menores para rBST em T3 e T4. Os tratamentos tiveram efeito significativo sobre peso dos cordeiros. As ovelhas em T3 apresentaram menor incidência de estro (52,9%), além de maior início (26,8±1,9 horas) e retorno ao estro (66,6%). A parição (86,2%) e a fecundidade (1,8±0,2) foram significativamente maiores em T2. A aplicação da rBST nas ovelhas incrementa o peso corporal dos cordeiros, em razão do aumento na produção de leite, mas afeta negativamente a atividade reprodutiva pós-parto, em razão da perda de peso corporal das ovelhas.

Abstract: The objective of this work was to evaluate the effect of recombinant bovine somatotropin (rBST) and of the metabolic restorative preparation Metabolase (MR) on the reestablishment of the post-partum ovarian activity of Pelibuey sheep. Ninety-four ewes, with their respective lambs, were randomly assigned to one of the following treatments: T1, continuous suckling (CS); T2, CS + MR; T3, CS + rBST; and T4, CS + MR + rBST. Ovulating percentages, weight changes in ewes and lambs, incidence of estrus, onset and return to estrus, calving, fecundity, and prolificacy were evaluated. The highest ovulation percentages were recorded for CS in T1 and T2, and the lowest ones for rBST in T3 and T4. The treatments had a significant effect on lamb weight. Ewes in T3 had the lowest incidence of estrus (52.9%), besides a greater onset (26.8±1.9 hours) and return to estrus (66.6%). Calving (86.2%) and fecundity (1.8±0.2) were significantly higher in T2. The application of rBST in ewes increases lamb body weight, due to increased milk production, but affects negatively post-partum reproductive activity due to the loss of ewe body weight.

ABSTRACT Biostimulation with "male effect" (ME) and its response in estrus synchronization in wool sheep was evaluated with a protocol based on the administration of prostaglandin (PGF2α) in the reproductive season. 24 Suffolk and 29 Rideau Arcott adult sheeps were used, which were randomized to one of two treatments (T): T1, n = 25: control sheep, synchronized with two applications of PGF2α with a seven-day interval, and T2, n = 28: similar to T1, but with the difference that the ram was introduced on day four, after the first administration of PGF2α, to perform ME. The estrus response, estrus onset, gestation and calving percentage, fertility, prolificacy, and fecundity were evaluated. There were no differences (P> 0.05) between the response to estrus, the percentages of gestation and calving, and fertility, among treatments. The onset of estrus, prolificacy and fecundity were higher (P <0.05) in the sheep of T2 with respect to the females of T1. We concluded that biostimulation with "male effect" in sheep synchronized with a protocol based on prostaglandins improves estrus onset, prolificacy, and fecundity in wool breeds.

RESUMEN Se evaluó la bioestimulación con “efecto macho” (EM) y su respuesta en la sincronización del estro en ovejas de lana con un protocolo basado en aplicación de prostaglandinas (PGF2α) en época reproductiva. Se utilizaron 24 ovejas adultas Suffolk y 29 Rideau Arcott, las cuales se distribuyeron al azar a uno de dos tratamientos (T): T1, n= 25: ovejas testigo, sincronizadas con dos aplicaciones de PGF2α con intervalo de siete días, y T2, n= 28: similar al T1, pero con la diferencia de que el carnero se introdujo en el día cuatro, de la primera aplicación de PGF2α, para realizar el EM. Se evaluó la respuesta al estro, inicio del estro, porcentaje de gestación, porcentaje de parición, fertilidad, prolificidad y fecundidad. No se encontraron diferencias (P >0.05) en la respuesta al estro, los porcentajes de gestación y parición, y la fertilidad entre tratamientos. El inicio del estro, la prolificidad y la fecundidad fueron mayores (P <0.05) en las ovejas del T2 con respecto a las hembras del T1. Se concluye que la bioestimulación con “efecto macho” en ovejas sincronizadas con un protocolo basado en prostaglandinas mejora el inicio del estro, la prolificidad y la fecundidad en razas de lana.

ABSTRACT Oregano oil is an aromatic used in poultry industry as a natural additive. This research was designed to quantify thymol and carvacrol in chicken breast meat. In total, 320 Broilers were fed on basal corn soybean meal diet contained crude soybean oil (CSO) or acidulated soybean oil (ASO) as a resource of energy with or without oregano oil (OO). Identification and measurement of compounds in meat was performed by gas chromatography (GC) and mass spectrometry (MS). Data obtained were transformed and analyzed parametrically, a significant increase of thymol and carvacrol was found in chicken breast meat supplemented with oregano oil (p < 0.05). Breast meat of broilers fed with oregano oil and CSO accumulated more thymol and carvacrol: 333% and 366%, respectively. Breast meat of broilers fed with oregano oil and ASO accumulated thymol, but more carvacrol: 552% and 648% respectively, compared with control. In conclusion, oregano oil supplementation in diet increased deposition of thymol and carvacrol in broiler meat.

RESUMEN El aceite de orégano es un aceite aromático usado en la industria avícola como un aditivo natural. Esta investigación fue diseñada para cuantificar el timol y carvacrol en carne de pechuga de pollo. En total, 320 pollos fueron alimentados con una dieta a base de maíz-pasta de soya, utilizando aceite de soya crudo (CSO, por sus siglas en inglés) o aceite de soya acidulado (ASO , por sus siglas en inglés) como fuente concentrada de energía, con o sin aceite de orégano (OO, por sus siglas en inglés). La identificación y cuantificación de los compuestos en la carne fueron realizadas con cromatografía de gases y espectrometría de masas. Los datos obtenidos fueron transformados y analizados paramétricamente, un incremento significativo de timol y carvacrol fue encontrado en pechuga de pollo suplementada con aceite de orégano (p < 0.05). La carne de pollos alimentados con aceite de orégano y CSO acumuló timol, pero más carvacrol: 333% y 366%, respectivamente. La carne de pollos alimentados con aceite de orégano y ASO acumuló timol, pero más carvacrol: 552% y 648%, respectivamente, comparado con el Testigo (sin aceite de orégano). En conclusión, la adición de aceite de orégano a la dieta incrementa la deposición de timol y carvacrol en carne de pollo.

Abstract In animal reproduction, natural methods like male effect (ME) and the action of neuroexcitatory amino acids accelerate puberty and induce ovulation in ewe lambs. In this study it was found that the biostimulation of the ewe and the neurotransmitter action of amino acids of a commercial energy tonic (CET, Metabolase®) may change the pulse frequency of luteinizing hormone (LH) and induce ovulation in prepubertal ewes. The objective was to evaluate the ME and CET action to induce ovulation and characterize the preovulatory peak of LH in prepubertal Pelibuey ewes. The experimental design included two factors (CET and ME) on two levels each (without: wo, and with: w). The treatments were randomized to 46 ewes: T1 (n = 12) control group: ewes without CET and without ME (woCETwoME), T2 (n=12) ewes with CET and without ME (wCETwoME), T3 (n=10) ewes without CET and with ME (woCETwME) and T4 (n=12) ewes with CET and with ME (wCETwME). Ovarian activity (OA) and the ovulation rate (OR) were evaluated by laparoscopy. The characteristics of the preovulatory peak of LH were evaluated in response to ME to confirm the first ovulation. The action of the CET, the male effect as well as their interaction, did not increase (p>0.05) the number of ovarian follicles of different diameters. The male effect and its interaction with the energy tonic increased (p≤0.05) the OR (woCETwME: 0.70 and wCETwME: 0.75). The response of the preovulatory peak of LH was similar (p>0.05) in ewes with ME with or without CET (wCETwME: 91.7 % and woCETwME: 70.0 %). The male effect and its interaction with CET induce the preovulatory LH peak and the first ovulation in prepubertal Pelibuey ewes.

Resumen En la reproducción, los métodos naturales como el efecto macho (EM) y la acción de los aminoácidos neuroestimuladores aceleran la pubertad e inducen la ovulación en corderas. En el presente estudio se consideró que la bioestimulación del carnero y la acción neurotransmisora de los aminoácidos, en un reconstituyente energético comercial (REC, Metabolase®), podrían modificar la frecuencia de pulsos de la hormona luteinizante (LH) e inducir la ovulación en ovejas prepúebres. El objetivo fue evaluar el EM y la acción del REC para inducir la primera ovulación y caracterizar el pico preovulatorio de LH en ovejas Pelibuey prepúberes. El diseño experimental fue con un arreglo de dos factores (REC y EM) en dos niveles cada uno (sin: s; con: c) y los tratamientos fueron asignados al azar a 46 ovejas: T1 (n=12) testigo, ovejas sin REC y sin EM (sRECsEM); T2 (n=12) ovejas con REC y sin EM (cRECsEM); T3 (n=10) ovejas sin REC y con EM (sRECcEM); y T4 (n=12) ovejas con REC y con EM (cRECcEM). La actividad ovárica (AO) y la tasa ovulatoria (TO) se evaluaron por laparoscopía. Las características del pico preovulatorio de LH se evaluaron en respuesta al EM para confirmar la primera ovulación. La acción del REC, el efecto macho, así como su interacción, no aumentaron (p>0.05) la cantidad de folículos ováricos de diferente diámetro. El efecto macho y su interacción con el REC aumentaron (p≤0.05) la TO (sRECcEM: 0.70 y cRECcEM: 0.75). La respuesta del pico preovulatorio de LH fue similar (p>0.05) en las ovejas con EM con o sin REC (cRECcEM: 91.7 % y sRECcEM: 70.0 %). El efecto macho y su interacción con el REC inducen el pico preovulatorio de LH y la primera ovulación en ovejas Pelibuey prepúberes.

Two experiments were carried out to evaluate selenium and vitamin E (Se-VE) in Pelibuey ewes. The application of Se-VE took place two days before progesterone (P) was no longer provided. The onset of estrus, the number of corpus luteum, fertility, lambing, fecundity and prolificacy were recorded. In the first experiment, 125 females were used and randomly assigned to one of eight treatments. P (T1; n = 12), P + Se-VE (T2; n = 12), P + Equine chorionic gonadotropin (eCG; T3; n = 12), P + Directed feeding (AD; T4; n = 12), P + Se-VE + eCG (T5; n = 12), P + Se-VE + AD (T6; n = 12), P + eCG + AD (T7; n = 12) and P + Se-VE + eCG + AD (T8; n = 12). Later, a ninth treatment was added (T9, Without drugs (SF), n = 29). In the second experiment, 178 females were used and randomly assigned to one of the following treatments. P (TI; n = 62), P + Se-VE + eCG (T2; n = 62) and SF (T3; n = 54). Data were analysed with a Chi-square test for variables in percentages, and with an analysis of variance for quantitative variables. In the first experiment, the beginning of estrus was different (p < 0.05) for T3 and T5. T9 was different from the other treatments (p < 0.05) for fertility, lambing and fecundity. In the second experiment, T2 was different (p < 0.05) for the onset of estrus. T2 and T3 were different (p < 0.05) for fertility, lambing and fecundity. It is suggested that the administration of Se-VE + eCG may be used as a strategy to improve estrus synchronisation and to homogenise its appearance in less time, without decreasing the reproductive efficiency of the Pelibuey ewes.

Se realizaron dos experimentos con la finalidad de evaluar el selenio y la vitamina E (Se-VE) en ovejas Pelibuey. La aplicación de Se-VE se realizó dos días antes del retiro de la progesterona (P). Se observó el inicio de estro, número de cuerpos lúteos, fertilidad, parición, fecundidad y prolifícidad. En el primer experimento se utilizaron 125 hembras asignadas al azar a uno de ocho tratamientos. P (T1; n = 12), P + Se-VE (T2; n = 12), P + Gonadotropina coriónica equina (eCG; T3; n = 12), P + Alimentación dirigida (AD; T4; n = 12), P + Se-VE + eCG (T5; n = 12), P + Se-VE + AD (T6; n = 12), P + eCG + AD (T7; n = 12) y P + Se-VE + eCG + AD (T8; n = 12). Posteriormente se adicionó un noveno tratamiento (T9, Sin fármacos (SF), n = 29). En el segundo experimento se utilizaron 178 hembras asignadas al azar a uno de los siguientes tratamientos. P (TI; n = 62), P + Se-VE + eCG (T2; n = 62) y SF (T3; n = 54). El análisis de datos se realizó mediante pruebas de Chi-cuadrada para las variables en porcentaje, y análisis de varianza para las variables cuantitativas. En el experimento uno, el inicio al estro fue diferente (p < 0.05) para T3 y T5. El T9 fue diferente del resto de los tratamientos (p < 0.05) para fertilidad, parición y fecundidad.En el experimento dos T2 fue diferente (p < 0.05) para el inicio del estro. El T2 y T3 fueron diferentes (p < 0.05) para fertilidad, parición y fecundidad Se sugiere que la administración de Se-VE + eCG puede utilizarse como una estrategia para mejorar la sincronización de estros y homogenizar su presentación en un menor tiempo, sin disminuir la eficiencia reproductiva de las ovejas Pelibuey.

Con el fin de determinar la tasa de manifestación del estro y la tasa de gestación en vaquillas Criollo Lechero Tropical (CLT), sincronizadas con una dosis baja (12,5 mg) de PGF2α. Cincuenta y cuatro vaquillas CLT cíclicas fueron asignadas al azar a 2 tratamientos: a) Dosis baja (DB; n=27): inyección intramuscular (IM) de 12,5 mg PGF2α; y b) Dosis completa (DC, n=27; grupo control): inyección IM de 25 mg PGF2α. Desde 12 h después de la PGF2α y durante 5 días se realizó detección de estros cada 4 h por 30 min para determinar el inicio y final del estro, su duración y la tasa de manifestación del estro. Las vaquillas recibieron inseminación artificial (IA) 12 h pos-estro detectado y fueron monitoreadas por ultrasonografía transrectal cada 4 h desde el final del estro hasta la ovulación para determinar el tiempo y tasa de ovulación. Las vaquillas que repitieron calor recibieron una segunda IA. Se diagnosticó la gestación 45 días pos-IA. La tasa de manifestación del estro y de ovulación fue 100% en ambos tratamientos. No hubo diferencia significativa (P>0,5) entre tratamientos en el tiempo de inicio del estro y de ovulación, duración del estro y tasa de gestación a primer servicio de IA. La tasa de gestación a segundo servicio de IA y la tasa de gestación general fueron significativamente mayores (P<0,05) para DB que para DC (77,7% y 74 vs 30% y 37%), respectivamente. La sincronización con dosis baja de PGF2α resultó en aceptable tasa de gestación general en vaquillas CLT, lo que significa menor costo del programa de sincronización

In order to determine estrus manifestation and pregnancy rates in Tropical Milking Criollo (CLT) heifers synchronized to estrus with a low dose (12,5 mg) of PGF2α fifty-four cyclic virgin CLT heifers were randomly assigned to two treatments: 1) Low dose (DB; n=27): i.m. injection of 12,5 mg PGF2α; and 2) Complete dose (DC, n=27; control group): i.m. injection of 25 mg PGF2α. From 12 h after PGF2α and during five days estrus was detected every 4 h for 30 min to determine the start and end of estrus, estrus duration and estrus manifestation rate. Heifers were artificially inseminated (IA) 12 h after estrus detection and were monitored by transrectal ultrasonography every 4 h from the end of estrus until ovuation to determine time and rate of ovulation. Repeat breeder heifers received a second IA service. Pregnancy was diagnosed 45 days after IA. Estrus manifestation and ovulation rates were 100% in both treatments. No significant (P>0.0%) difference was found among treatments for time of estrus and ovulation, estrus duration or pregnancy rate at first IA service. Pregnancy rate at second IA service and overall pregnancy rate were significantly (P<0.05) higher for DB than for DC (77.7% and 74% vs 30% and 37%), respectively. Estrus synchronization with a low dose of PGF2α resulted in an acceptable overall pregnancy rate in CLT heifers, which is reflected in a lower cost of the estrus synchronization program

Se evaluó la tasa de desarrollo de blastocistos bovinos producidos in vitro utilizando medio de cultivo convencional para embriones bovinos y medio de cultivo para producción in vitro (PIV) de embriones humanos. Se obtuvieron ovocitos de ovarios de vacas Cebú sacrificadas en matadero. Los folículos ováricos fueron aspirados y los complejos cumulus-ovocitos (CCO) con al menos dos capas de células del cumulus intactas fueron madurados durante 22 a 24 h. Posteriormente, los CCO fueron fertilizados con semen bovino descongelado y coincubados por 20 a 24 h. Los presuntos cigotos fueron cultivados por 48 h en medio KSOM o en medio HTF modificado. En los días 3 y 5 post-fertilización in vitro (FIV), los embriones fueron cambiados a gotas nuevas de KSOM o de IVC-Two/IVC-Three. Para ambos cultivos, en el día 3 post-FIV se determinó la tasa de división y entre los 7 a 9 días post-FIV, se evaluó el desarrollo embrionario a etapa de blastocisto. La tasa de maduración in vitro fue 89,7%. La tasa de división fue 82,3% para ovocitos cultivados en KSOM y de 80,1% para ovocitos cultivados en HTF (P>0,05). La tasa de desarrollo de blastocistos fue 31,6% para embriones cultivados en KSOM y 29,5% para embriones cultivados en HTF/IVC-Two/IVC-Three (P>0,05). En conclusión, las tasas de desarrollo in vitro de blastocistos bovinos fueron similares para los embriones cultivados en un medio convencional para PIV de embriones bovinos y para los embriones cultivados en medios utilizados para PIV de embriones humanos, por lo que ambos tipos de medios pueden utilizarse para la PIV de embriones bovinos con resultados aceptables.

The objective of this study was to evaluate the blastocyst development rate for in vitro produced bovine embryos using either the conventional culture medium for bovine embryos or culture media used for the in vitro production (IVP) of human embryos. Oocytes were obtained from ovaries of slaughtered Zebu cows. Ovarian follicles were aspirated and the cumulus-oocytes complexes (COC) with at least two layers of intact cumulus cells were matured for 22 to 24 h. Following that, COC were fertilized with frozen-thawed bovine semen and coincubated for 20 to 24 h. The presumptive zygotes were cultured for 48 h in KSOM medium or modified HTF medium. On days 3 and 5, post-in vitro fertilization (IVF) embryos were placed into new drops of KSOM or IVC-Two/IVC-Three. For both culture types, the cleavage rate was determined on day 3 post-IVF and the embryo development rate to blastocyst stage was evaluated on days 7 to 9 post-IVF. In vitro maturation rate was 89.7%. Cleavage rate was 82.3% for oocytes cultured in KSOM and 80.1% for oocytes cultured in HTF (P>0.05). Blastocyst development rate was 31.6% for embryos cultured in KSOM and 29.5% for embryos cultured in HTF/IVC-Two/IVC-Three (P>0.05). In conclusion, in vitro blastocyst development rates were similar for both the embryos cultured in the conventional medium for IVP of bovine embryos and the embryos cultured in media used for the IVP of human embryos, thus, both types of media can be used for the IVP of bovine blastocysts with acceptable results.

La finalidad del presente estudio fue determinar el efecto del amamantamiento en la duración del intervalo parto-primera ovulación (IPPO), los cambios de peso corporal (CPC) posparto de las hembras y la ganancia diaria de peso (GDP) y mortalidad (M) de los corderos durante los primeros 90 d posparto en la raza Pelibuey. Cuarenta y dos ovejas multíparas con sus crías se asignaron al azar a uno de tres tratamientos: amamantamiento continuo (AC; n=16), amamantamiento restringido (AR; n= 16) y destete precoz (DP; n= 10). Los corderos en AC permanecieron con sus madres las 24 h del día con amamantamiento ad libitum; en AR, los corderos amamantaron durante 30 min al día (08:00 a 08:30); y en DP, las crías se separaron de sus madres desde los 7 d de nacidos sustituyéndose la alimentación con sustituto de leche. Para eliminar el efecto confundido de la época del año en los resultados obtenidos en el manejo del amamantamiento, se integró un grupo testigo con ovejas no gestantes (OV; n= 15). La eliminación del amamantamiento con el destete total (DP) de los corderos a los 7 d de edad aumentó el número de ovejas que ovularon antes de los 56 d posparto, disminuyó el IPPO y la pérdida de peso de las ovejas (P<0,05), disminuyó la GDP de las crías y aumentó la M de los corderos respecto a AC y AR (P<0,05). El AR disminuyó el IPPO con respecto a AC, mejoró la GDP y disminuyó la M de los corderos con respecto a DP (P<0,05). El AR parece ser el mejor sistema de manejo para un adecuado desarrollo del cordero y reiniciar la actividad reproductiva de las ovejas durante los primeros tres meses posparto.

It was studied the effects of suckling on ewe parturition-first ovulation period (IPPO), changes in post-parturition body weight (CPC), and lamb daily weight gain (GDP) and mortality (M) during the first 90 d postpartum. Forty-two multiparous Pelibuey ewes with lambs were randomly assigned to one of three suckling treatments: continuous suckling (AC; n=16), restricted suckling (AR; n=16) and early weaning (DP; n=10). Ewes and lambs in AC stayed together 24 h a day nursing ad-libitum, ewes and lambs in AR stayed together for only 30 min a day (from 08:00 to 08:30) to nurse, and lambs in DP were permanently separated from their mothers at day 7 after lambing and fed with a milk formula. A blank treatment consisting of non-pregnant ewes (OV; n=15) was included to remove the effect of season on treatments. Early weaning at day 7 after birth increased the number of ewes ovulating during the first 56 days postpartum, decreased the IPPO and weight lost of ewes (P<0.05), decreased lamb GDP and increased M relative to AC and AR (P<0.05). AR decreased the IPPO compared to AC, improved lamb GDP and decreased M compared to DP (P<0.05). Restricted suckling appears to be a better system for raising lambs and restore reproductive activity of ewes during the 3 month postpartum period.

L-arginine is a substrate of the enzyme nitric oxide synthase for production of nitric oxide (NO), which has an influence in reproductive physiology, while fish oil inhibits the production of NO. Therefore, an study was performed about the effects of a supplement (for 3 d) of L-arginine (A) (for 3 d) and fish oil (AC) on the onset of estrus (E), percentage of estrus (PE), ovulatory rate (TO), percentage gestation (PG) and prolificity (PR) in hair sheep ewes treated (12 d) with 40 mg of fluorogestone acetate (AFG) using an impregnated polyurethane sponge inserted into the vagina. The treatments were the following: P=progesterone oil alone (n=7); AFG+eCG=40 mg fluorogestone acetate (12 d) + 400 IU equine chorionic gonadotropin (eCG; n=8); AFG+A=AFG+300mg kg-1 A (n=10); AFG+AC=AFG+ 6 % AC (n=11); AFG+A+AC (n=8). E was different (p<0.05) in ewes treated with AFG+eCG with 33.20±3.9 h. PE was not different among ewes treated with AFT + eCG, AFG+A and AFG+AC, but it was different (p<0.05) from that of those treated with AFG+A+AC and those treated with P alone. TO among ewes was different (p<0.05) for AFG+A (1.70±0.13), AFG+A+AC (1.80±0.13), AFG+AC (1.60±0.16) corpora lutea per ewe vs AFG+ECG (1.50±0.19) and P (1.40±0.25). PG was different (p<0.05) en AFG+eCG 100% (8/8) and AFG+AC 90.9 % (10/11) vs AFG+A 70.0 % (7/10) and AFG+A+AC 87.5 % (7/8) and P 28.6 % (2/7). PR was different (p<0.05): the largest number of lambs per ewe was obtained with AFG+A (1.7±0.18) and the smallest number with AFG+A+AC (1.1±0.14). There was no difference in PR among the ewes treated with P (1.5±0.50), AFG+eCG (1.4±0.18) and AFG+AC (1.4±0.16). The ewes treated with AFG+A and AFG+AC showed reproductive characteristics similar to those treated with AFG+ eCG and better characteristics than those treated with P alone. There was a negative interaction in PR with the supplement A+AC. A apparently influences the reproductive behavior of hair sheep ewes.

L-arginina es el sustrato de la enzima óxido nítrico sintetasa para la producción de óxido nítrico (NO), el cual influye en la fisiología reproductiva, mientras que el aceite de pescado inhibe la producción de NO. Por tanto, se estudiaron los efectos de un suplemento (por 3 d) de L-arginina (A) y aceite de pescado (AC) en el inicio del estro (E), porcentaje de estros (PE), tasa ovulatoria (TO), porcentaje de gestación (PG) y prolificidad (PR) en ovejas de pelo tratadas (12 d) con 40 mg de acetato de fluorogestona (AFG) impregnada en esponja de poliuretano vía intravaginal. Los tratamientos fueron: P=sólo progesterona oleosa (n=7); AFG+eCG=40 mg acetato de fluorogestona (12 d) + 400 UI gonadotropina coriónica equina (eCG; n = 8); AFG+A=AFG + 300 mg kg-1 A (n=10); AFG+AC = AFG + 6 % AC (n=11); AFG+A+AC (n=8). El E fue diferente (p<0.05) en las ovejas del AFG+eCG con 33.20 ± 3.90 h. El PE no fue diferente entre las ovejas de AFG+eCG, AFG+A y AFG+AC, pero diferente (p<0.05) con respecto a AFG+A+AC y P. La TO entre las ovejas fue diferente (p<0.05) para AFG+A (1.70±0.13), AFG+A+AC (1.80±0.13), AFG+AC (1.60±0.16) de cuerpos lúteos por oveja vs AFG+eCG (1.50±0.19) y P (1.40±0.25). El PG fue diferente (p<0.05) en AFG+eCG 100 % (8/8) y AFG+AC 90.9 % (10/11) vs AFG+A 70.0 % (7/10) y AFG+A+AC 87.5 % (7/8) y P con 28.6 % (2/7). La PR fue diferente (p<0.05): el mayor número de corderos por oveja se obtuvo con AFG+A (1.7±0.18) y el menor número con AFG+A+AC (1.1±0.14), no hubo diferencia en PR entre las ovejas de P (1.5±0.50), AFG+eCG (1.4±0.18) y AFG+AC (1.4±0.16). Las ovejas tratadas con AFG+A y AFG+AC presentaron características reproductivas similares a aquellas de AFG+eCG y mejor que con P. Hubo una interacción negativa en la PR con el suplemento de A+AC. Aparentemente A influye en el comportamiento reproductivo de la oveja de pelo.

The influence of nutrition on ovarian function can be measured through changes in metabolic hormone levels and the superfamily of growth factors, but its relative importance and paths of action need to be determined. In the present study, 32 adult goats (7/8 Saanen-Alpina x 1/8 Criollo) were exposed to a divergent feeding period of 40 d to form two groups with low (LBC) and high (HBC) body condition (BC). The experiment included 40 d pre and 15 d post-ovulation. Goats received 70 % and 100 % of the nutritional requirements; the base diet was ground alfalfa hay plus a non-degradable protein supplement in rumen (NDPR): 0 g and 103.95 g. Both body weights in fasting and the BC were taken at the beginning of the study and every 15 d. Two applications with cloprostenol were used to synchronize the estrus of goats; 24 h after the second application, in pre-ovulatory follicular phase, 16 goats (four goats per treatment) were selected for two blood samplings and to detemine the serum concentration of the IGF-I through RIA. The total ovarian activity (TOA) was evaluated through ultrasonagraphy, registering the number of corpus luteum (CLN), total follicles (TF), antral follicles (AF), TOA-1 (CLN+TF) and TOA-2 (CLN+AF). The supplement with NDPR increased CLN and TF (p<0.01), TOA-1, TOA-2 and IGF-I (p<0.01), and there was a positive correlation (p<0.05) of IGF-I with NDPR (R = 0.53) and with BC scoring (R=0.51). For HBC there was a higher response in TOA-1 (p<0.05), TOV, CLN, AF, TOA-2 and IGF-I (p<0.01). It is concluded that in adult female goats a supplement with NDPR and a good BC in the stage prior to mating, improves the ovarian response and is positively related to an increase in the circulating levels of IGF-I.

La influencia de la nutrición en la función ovárica es mediada por cambios en niveles de hormonas metabólicas y de la superfamilia de factores de crecimiento, pero su importancia relativa y rutas de acción necesitan ser dilucidadas. En el presente estudio se usaron 32 cabras adultas (7/8 Saanen-Alpina x 1/8 Criollo), con un periodo de alimentación divergente de 40 d para formar dos grupos con condición corporal (CC) baja (CCB) y alta (CCA). El experimento tuvo 40 d pre y 15 d post-ovulación. Las cabras recibieron 70 % y 100 % de los requerimientos nutricionales; la dieta base fue heno de alfalfa molido más un suplemento de proteina no degradable en rumen (PNDR): 0 g y 103.95 g. Los pesos corporales en ayuno y la CC fueron registrados al inicio del estudio y cada 15 d. Dos aplicaciones con cloprostenol fueron usadas para inducir el celo de las cabras; 24 h después de la segunda aplicación, en fase folicular preovulatoria, 16 cabras (cuatro cabras por tratamiento) fueron seleccionadas para dos muestreos sanguíneos y determinar la concentración sérica del IGF-I mediante RIA. La actividad ovárica total (AOT) se evaluó mediante ultrasonografía, registrando el número de cuerpos lúteos (CLT), folículos totales (FT), folículos antrales (FA), AOT-1 (CLT + FT) y AOT-2 (CLT + FA). El suplemento con PNDR aumentó CLT y FT (p<0.05), AOT-1, AOT-2 e IGF-I (p<0.01) y hubo una correlación positiva (p<0.05) de IGF-I con PNDR (R=0.53) y con la calificación de la CC (R=0.51). Para CCA hubo una mayor respuesta en AOT-1 (p<0.05), VOT, CLT, FA, AOT-2 e IGF-I (p<0.01). Se concluye que en cabras adultas un suplemento con PNDR y una buena CC en la etapa previa al empadre, mejora la respuesta ovárica y se relaciona positivamente con un aumento en los niveles circulantes de IGF-I.