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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.

Objective: To describe the function of Fec, CA5A and CLSTN2 genes during ovulation in ewes. Design/methodology/approach: A search and analysis of scientific information related to Fec, CA5A and CLSTN2 genes in sheep was performed. Results: Fec, CA5A and CLSTN2 genes are involved at the ovarian level; ewes carrying the first gene were found to have increased ovulation rate, folliculogenesis and granulosa cell differentiation. CA5A stimulates an increased follicular rate and plays an important role in pre-implantation. While CLSTN2 has activity in ovarian development and growth; it also has the ability to interact with other genes involved in follicular maturation, granulosa cell differentiation and development of the ovarian follicle. Limitations on study/implications: Ewes carrying these genes increase the prolificacy rate in the flock. Findings/conclusions: The expression of these genes acts synergistically in the ovulatory process, enhancing the ovulatory response by contributing to endocrine, paracrine and molecular synchronisation, so that the maturation of the oocyte occurs, leading to ovulation.

Se estudió la respuesta de corderos Pelibuey (P), Blackbelly (BB) y Dorper x Pelibuey (DxP) a una infección experimental con nematodos gastrointestinales (NGI). Se utilizaron 21 corderos P de dos meses de edad, 15 BB de tres meses de edad, y 14 DxP de dos meses de edad, con pesos vivos (PV) de 12.0±3.2, 13.6±3.9, y 13.0±3.6 kg, respectivamente. El experimento se efectuó en dos etapas de 30 días cada una, la primera en pastoreo y la segunda en confinamiento. En ambas etapas, los corderos se infectaron con 3,000 larvas (L3) de una mezcla de NGI. Cada siete días se recolectaron muestras de heces para contar el número de huevos por gramo de heces (HPG) y sangre para medir el volumen celular aglomerado (VCA), además de registrar su PV, condición corporal (CC) y la coloración de la mucosa ocular (CMO). Los corderos BB y DxP tuvieron mayores conteos fecales (5,259±654 y 5,515±654 HPG), mientras que los P, los menores (3,252±515, P

One of the strategies to genetically improve reproductive traits, despite their low inheritability, has been the identification of candidate genes. Therefore, the objective of this study was to detect candidate genes associated with fecundity through the fixation index (FST) and runs of homozygosity (ROH) of selection signatures in Katahdin ewes. Productive and reproductive records from three years were used and the genotypes (OvineSNP50K) of 48 Katahdin ewes. Two groups of ewes were identified to carry out the genetic comparison: with high fecundity (1.3 ± 0.03) and with low fecundity (1.1 ± 0.06). This study shows for the first time evidence of the influence of the CNOT11, GLUD1, GRID1, MAPK8, and CCL28 genes in the fecundity of Katahdin ewes; in addition, new candidate genes were detected for fecundity that were not reported previously in ewes but that were detected for other species: ANK2 (sow), ARHGAP22 (cow and buffalo cow), GHITM (cow), HERC6 (cow), DPF2 (cow), and TRNAC-GCA (buffalo cow, bull). These new candidate genes in ewes seem to have a high expression in reproduction. Therefore, future studies are needed focused on describing the physiological basis of changes in the reproductive behavior influenced by these genes.

El uso de biotecnologías reproductivas, permiten mejorar la productividad de los ovinos, esto combinado con nutrición focalizada de corta duración con fuentes energéticas o proteicas pueden generar sinergia en los resultados. En las regiones tropicales, el uso de vaina de leguminosas representa una alternativa nutricional en rumiantes. Por lo que, el objetivo de esta investigación fue conocer el efecto de las vainas de dos leguminosas tropicales; Leucaena leucocephala y Guazuma ulmifolia, bajo la hipótesis de que su uso mejora la repuesta reproductiva en ovejas de pelo o lana. El experimento se realizó en el Colegio de Posgraduados, Montecillo, Texcoco, México. Se utilizaron 48 ovejas de pelo y 27 de lana, en libre pastoreo, distribuidas en 4 tratamientos, el T1 y T3 se les ofreció 350 gr de vainas de leguminosas por seis días antes del servicio, todas las ovejas se sincronizaron con progestágeno y prostaglandinas, Las variables no paramétricas se analizaron con el método de curvas de sobrevivencia Log-Rank, utilizando el procedimiento Life Test (SAS, 2011); y la comparación de medias se realizó por el método de Bonferroni (SAS, 2011). El porcentaje de celos no mostro diferencia (P0.05), mientras que horas al celo, porcentaje de gestación y prolificidad mostró diferencia (P0.05) entre tratamientos, en favor de T1 y T3. Se concluye que el uso de vainas de leguminosas en nutrición focalizada ultracorta mejora la respuesta reproductiva de ovejas.

The goal of this research was to evaluate the nutritive value of full-fat de-hulled sunflower seeds (DHSS) in feeding broiler chickens. Three experiments were conducted. Experiment 1 determined the proximal analysis of DHSS, the essential amino acid content, and apparent metabolizable energy (AME). In experiment 2, two diets were formulated, namely a control and a diet containing 10% DHSS. Apparent ileal digestibility (AID) of dry matter (DM), crude protein (CP), and ether extract (EE) were calculated. In experiment 3, the performances of broilers fed the two diets were evaluated in terms of the relative weights of digestive system organs, breast meat colour, growth and feed consumption. Full-fat de-hulled sunflower seeds were characterized as having 507.9 g/kg EE, 282.1 g/kg CP, 21.02 MJ/kg AME and 9.3 g/16 g N arginine. Apparent ileal digestibility of DM in the 10% DHSS diet was 658.0 g/kg, similar to that of the control diet (643.0 g/kg). Partial substitution of DHSS for soybean meal (SBM) did not affect the relative weight of digestive system organs, except for the liver. The relative weights of the liver were 17.90 g/kg bodyweight in birds fed the DHSS diet and 16.37 g/kg bodyweight (P

The objective of this study was to estimate the good-of-fitness and precision of parameters of the Gompertz-Laird, Logistic, Richards, and Von Bertalanffy growth models, using different data collection periods (DCP). Two hundred and sixty-two Mexican Creole chicks (116 females and 146 males), were individually weighed to form the following sets of data for each sex: DCP

Objective: To describe the management strategies of controlled suckling and the male effect to reduce postpartum anestrus, and to show the participation of kisspeptin to regulate the effect of both factors. Design/Methodology/Approach: A review of scientific publications was conducted, in order to show the importance of suckling and the male effect as strategies to reduce postpartum anestrus in the ewe, as well as the relation of kisspeptin with both factors. Results: Seasonal anestrus can be avoided with the use of breeds adapted to the local environment, such as Pelibuey. Postpartum anestrus occurs mainly as a result of suckling, since the latter inhibits the pulsating secretion of the gonadotropin-releasing hormone (GnRH) and the luteinizing hormone (LH). The exact path of this inhibition is unknown, although it seems that endogenous opioid peptides and kisspeptin are intermediaries. Controlled suckling and the male effect are management strategies that improve the reproductive behavior of postpartum ewes. Kisspeptin regulates the influence of the male effect through the secretion of GnRH/LH. Study Limitations/Implications: To understand the impacts of suckling and the male effect on the duration of postpartum anestrus, as well as the participation of kisspeptin in the regulation of both effects, will allow designing management strategies to improve the reproductive efficiency of the ewes. Findings/Conclusions: Controlled suckling and the male effect reduce postpartum anestrus and improve the reproductive behavior of the ewes; advancing knowledge of the kisspeptin effect could improve the effectiveness of both techniques.

Objective: To review information related with the reproductive physiology and management of white-tailed deer for reproductive specialists and producers. Design/methodology/approach: The information presented in this document relies on the review of scientific papers and on experience gained in white-tail deer production systems. Results: White-tailed deer is a species with seasonal reproduction and one of the most important hunting species in Mexico. Currently, all reproductive biotechnologies applied to small ruminants can be used in white-tailed deer. Limitations of the study/implications: Information regard the physiology and reproductive management of white-tailed deer is limited, probably due to conditions specific to its production system. Findings/conclusions: Research and publication of information regard the physiology and reproductive management of white-tailed deer is needed.

Objective: To evaluate the effect of excess fat and suckling control on postpartum reproductive activity of hair ewes. Design/Methodology/Approach: Eighty-one (81) hair ewes with average weight of 58±8 kg were used, which on postpartum day 7 were assigned to one of four treatments under a completely randomized design with 2×2 factorial arrangement. Factor A is the type of suckling [continuous suckling (CS) and suckling control (SC)] and factor B, excess fat (with or without). In CS, ewes remained with their offspring 24 hours a day (n=16). In continuous suckling plus fat (CSF), ewes remained with the offspring all day plus the addition of 8% in dietary fat (n=24). In SC, it was 30 min of suckling only twice per day (n=14). In suckling control plus fat (SCF), controlled suckling lasted 30 min, twice a day plus 8% fat (n=25). Results: The response to the treatments was similar (p > 0.05) in onset of estrus, return rate, gestation, prolificacy and fertilization; for the lambing rate variable, there were differences (p ≤ 0.05), the SCF treatment was higher (68%) compared to CS (50%) and CSF (50%), but equal (p < 0.05) to SC (57.1%). Implications: In this experiment, it was observed that the SCF treatment presented a better response, implying that controlling suckling and providing excess fat helps to restore ovarian activity sooner after lambing. Conclusions: Suckling control plus inclusion of dietary excess fat in ovulation induction protocols during early postpartum (around day 25 postpartum) can be included in routine reproductive management of flocks, improving the reproductive efficiency of hair sheep.

Objective: To review the metabolic and hormonal processes that regulate reproductive activity in dairy cattleduring the postpartum anestrus period.Design/methodology/approach: Analysis of scientific documents and systematization of information relatedto the reproductive physiology and management of dairy cattle in postpartum anestrus.Results: Postpartum anestrus is an event that occurs naturally and is necessary for restoration of the homeostasisof the cow’s body following calving. However, failure to reestablish this homeostasis actually increases itsduration and negatively affects the subsequent reproductive performance of the individual cow.Limitations on study/implications: Reproductive management decisions must be based on scientificknowledge.Findings/conclusions: Management of dairy cattle in the postpartum anestrus period should focus onreestablishment of the state of homeostasis and the subsequent reproductive activity, with nutritional andhormonal strategies implemented to induce cyclicity, ovulation and formation of the first corpus luteum in thatperiod, through application of exogenous hormones after day ten postpartum.

Objective: To describe the involvement of the interferon tau gene in the maternal recognition of pregnancy in sheep. Design/Methodology/Approach: A search and analysis of the scientific documents retrieved from the Web of Science and Scopus databases related to the functions of the interferon tau gene in the maternal recognition of pregnancy in sheep were conducted. Results: The interferon tau gene (IFNτ) participates in maternal recognition of pregnancy to avoid possible rejection of the embryo, and supports the secretion of progesterone involved in preparing the endometrium for implantation; it also inhibits myometrial motility to maintain pregnancy. IFNτ stimulates the transcription of so-called interferon-stimulated genes (ISGs), which are the effectors of cell-autonomous antiviral defense. One of the representative members of ISGs is the interferon 15-stimulated gene (ISG15) which regulates endometrial receptivity at implantation, as well as survival, growth and development of the conceptus. Study Limitations/Implications: Most embryonic losses occur between fertilization and maternal recognition of pregnancy. Understanding this issue is essential to understanding the possible causes of early pregnancy losses. Findings/Conclusions: Considerable progress has been made in the discovery of how the IFNτ and ISG15 genes act in maternal recognition of gestation in sheep

Objective: To determine the changes in seminal quality of Pelibuey and East Friesian rams during the non-breeding (long days; March-June) and breeding seasons (short days; September-December) at 19° north latitude. Design/methodology/approach: To determine changes in seminal quality over time, seminal parameters of rams, collected with an artificial vagina were evaluated over 32 weeks. An analysis of variance was performed with a completely randomized design in a 2 x 2 factorial arrangement (breed and season). Results: No differences were found within breeds or between breeds in the same season in the evaluated seminal parameters; however, differences were reported between seasons in the live weight parameters, lower in the non-reproductive season, in addition to an increased scrotal circumference and mass motility during the reproductive season. Study limitations/implications: Semen parameters estimation, in field trials, is subjective compared to computerized semen evaluation systems, it is therefore desirable to have extensive experience in semen evaluation at the field level before starting the study. To confirm the results obtained in this study, a new experiment with a larger number of experimental units is suggested. Findings/conclusions: It is concluded that in the environmental and management conditions, where the seminal evaluation took place, no differences were found between breeds, suggesting that the Pelibuey and East Friesian breeds at 19° north latitude do not decrease their seminal parameters during the non-breeding season compared to the breeding season. This suggest that these two sheep breeds are able to reproduce, in such conditions, all year round.

Objective: To describe the factors affecting male goat (buck) reproduction and the selection and management strategies to improve their reproductive efficiency. Design/Methodology/Approach: By reviewing published information, the main factors that affect the reproductive capacity of bucks and some management strategies for their reduction were described. Emphasis was on the evaluation of seminal quality, libido, and the selection of sires to be used in the herd. Results: Proper sire diet reduces age at puberty and improves testicular and seminal characteristics, as well as sexual behavior. The effect of seasonality can be improved by using melatonin implants and adequate nutrition. Study Limitations/Implications: In goat production systems, bucks are important for the production of quality livestock and the products and byproducts from this species. Understanding the impact of environmental factors such as nutrition, seasonality, and physiological processes on the reproductive capacity of bucks promotes the establishment of management strategies to better understand what is important when selecting sires as sperm donors to improve product quality and to obtain greater herd production. Findings/Conclusions: Adequate sire nutrition improves herd fertility. Seasonal reproduction affects the reproductive capacity of sires as sperm donors, yet there are management alternatives to reduce such seasonal effects on their reproductive performance.

Objective: To share technical aspects and recommendations to improve the reproductive and productive efficiency of dual-purpose cattle. Design/Methodology/Approach: A review of scientific articles published in journals was carried out to show the importance of some factors that limit reproduction, as well as to identify management strategies to increase the reproductive potential in dual-purpose cows. Results: The duration of postpartum anestrus is reduced by weaning calves at a few days or weeks of age, restricting suckling to short periods of the day, delaying suckling, and exposing cows to a bull during postpartum. On average, the combined effect of delayed suckling and exposure of cows to a bull reduces postpartum anestrus to less than 50 d and the calving-conception interval to 84 days. Milk production and calf weight gain also are improved without affecting postpartum weight changes in cows. Study Limitations/Implications: Extensive management of dual-purpose cattle reduces the intensive use of some reproductive biotechnologies commonly applied in other animal production systems. Findings/Conclusions: Improvement in the reproductive efficiency of dual-purpose cattle can be achieved by reducing the postpartum anestrus by using reproductive management strategies and minor modifications to common management practices.

Objective: To describe the anatomy, morphology, physiology, and reproductive characteristics of female turkeys. Design/methodology/approach: An analysis of the practical experiences of 10 years with Mexican native turkeys was conducted and complemented with scientific literature. We focused on reproductive aspects, anatomy, physiology and assisted reproduction. Results: Information on the breeding of Mexican native turkeys is scarce, few families in rural areas are dedicated to raising this poultry. Therefore, empirical knowledge on their management is being lost. The female turkey begins oviposition at 6 months of age with a body weight between 2 and 4 kg. The structures that make up their reproductive system are the ovary, developing follicles, left oviduct, and cloaca. The reproductive activity is initiated by photo receptors located in the retina and pineal gland, triggering follicle stimulating and luteinizing hormones release. Egg formation lasts from 24 to 26 hours. During the first year, females lay between 36 to 54 eggs in clutches of 12 to 18 eggs and in the second year from 30 to 45 eggs. Chloequez is prolactin induced. As for assisted reproduction, artificial insemination techniques in female turkeys are uncommon. Limitations on study/implications: Few rural families raise turkeys and since they lack economic resources, reproductive strategies are not used to improve their production. Findings/conclusions: The anatomical, morphological, physiological and reproductive characteristics of the native female turkeys from Mexico were documented. In native turkeys, artificial insemination techniques are not of common use, but their implementation may be adequate to conserve genetic material from animals with outstanding characteristics.

Objective: To describe the morphophysiology and reproductive characteristics of the male turkey. Methodology: An analysis based on the practical experiences from over 10 years with the native Mexican turkey was developed and complemented with literature reports. Results: In Mexico the production management is customs based on traditions and beliefs. In their reproductive morphophysiology, the epididymis absence stands out, as well as a rapid testicular growth during the breeding season, which is controlled by the photoperiod. Limitations of the study: Native turkey farming is practiced in backyard, in marginalized and low-resource areas that have no strategies (nutritional and reproductive) to improve their production. Conclusions: The anatomical, morphological, physiological and reproductive characteristics of the native Mexican turkey were documented. The knowledge on these characteristics will allow to develop feeding and reproductive strategies to improve the productive and reproductive performance of the native turkey and preserve their genetic resources.

Objective: To estimate the lactation curve and milk production of Pelibuey ewes andthe relationship with preweaning growth rate of the lambs.Design/methodology/approach: Forty five Pelibuey ewes were milked during 70days in Montecillo, México, in 2018, to estimate daily and total milk production. Thelactation curve was fitted with the incomplete gamma function. In addition, the effectsof type of birth and ewe weight at milking on milk production were analyzed, andcorrelations were calculated between ewe milk production and growth rate of thelambs, per week and for the entire lactation Results: A “typical” lactation curve was found, average ewe milk production for theentire lactation, weighted for the number of lambs suckling, was 131±8 L, with444±24 g d -1 . Ewe weight at milking had an effect (p

Objetivo: Evaluar los cambios en las características del eyaculado de carneros machos de pelo durante el año a 19° LN.Diseño/metodología/aproximación: Se utilizaron ocho carneros de pelo con edad de 11.5±0.5 meses y peso vivo de 62 ± 6 kg, a los cuales se les recolectó semen cada 15 d de marzo del 2013 a febrero del 2014, el periodo de evaluación se dividió en dos épocas: 1) época reproductiva (R) y 2) época no reproductiva (A). En cada eyaculado se evaluó, el volumen (V), concentración espermática (CE), movilidad masal (MM) y el porcentaje de espermatozoides vivos y anormales. Los resultados se analizaron por época utilizando el ANDEVA por medio del procedimiento GLM y comparación de medias por la prueba de Tukey; las variables ambientales se correlacionaron con las características seminales por el procedimiento CORR de SAS.Resultados: Las características seminales fueron diferentes entre épocas (P ? 0.05). El mayor V, CE, MM y porcentaje de vivos se observó durante la R (1.4 mL y 2.4 X10 9 , 4.5 y 90%, respectivamente). Se encontró correlación negativa (P ? 0.05) entre la movilidad y el fotoperiodo (-0.73).Limitaciones del estudio/implicaciones: La calidad seminal de los carneros de pelo, fuera de la época reproductiva se reduce.Hallazgos/conclusiones: A 19° LN los carneros de pelo presentan un patrón de reproducción estacional, y durante la R se encuentran las mejores características del eyaculado.

The growth and differentiation factor 9 (GDF9) intervenes in the fecundity and prolificacy of the ewe, which are important variables that participate in the reproductive efficiency of a flock. The objective of this study was to evaluate the influence of FecGE mutation of the gene GDF9 in the natural response of the manifestation to estrus, return to estrus, ovulation rate, pregnancy, lambing, prolificacy, and fecundity rate in Pelibuey ewes, during the anestrus period. The sequences of the exon 2 of the gene GDF9 were obtained from blood samples collected in Whatman™ FTA™ cards from 42 multiparous Pelibuey ewes with reproductive records. For this purpose, the quality of the sequences was analyzed and the polymorphisms and genotypes were searched for. The ewes were grouped according to their group: (a) homozygous or Embrapa (GG), (b) wild (AA), and (c) group without gene (sG). All the ewes studied manifested estrus behavior, but none showed signs of return to estrus after natural mating (p > 0.05); likewise, the pregnancy and lambing rates (p > 0.05) did not show differences between groups. However, the group GG presented higher ovulation rate, prolificacy, and fecundity rate (p < 0.05), compared to groups AA and sG. Although no differences were found in the manifestation of estrus, return to estrus, and percentage of pregnancy and lambing in females from the genotypes studied, the homozygous ewes GG presented 1.22 and 1.72 more corpus luteum (CL, p < 0.05), prolificacy of 0.7 and 0.7, and fecundity rate of 0.8 and 1.0 more lambs per ewe (p < 0.05) than the ones produced by the wild-type AA and sG groups, respectively.

The growth and differentiation factor 9 (GDF9) intervenes in the fecundity and prolificacy of the ewe, which are important variables that participate in the reproductive efficiency of a flock. The objective of this study was to evaluate the influence of FecG

Objetivo: describir la función de los genes GDF9, BMP15 y BMPR-IB en tasa ovulatoria y prolificidad en ovejas.Diseño/metodología/aproximación: Se realizó una búsqueda y un análisis de la información científica relacionada con genes de la fecundidad en ovejas, a partir de las bases de datos de la Web of Science y Scopus. Resultados: en los genes de la fecundidad, se tiene el Factor de Crecimiento y Diferenciación 9 (GDF9), la Proteína Morfogénica Ósea 15 (BMP15) y el receptor de la Proteína Morfogénica Ósea tipo 1B (BMPR1B), que pertenecen a la familia del Factor de Crecimiento Transformante tipo ß (TGFß). En la mayoría de las mutaciones encontradas en las regiones codificantes de estos genes, las ovejas heterocigotas aumentan tasa ovulatoria y prolificidad; mientras que, las homocigotas son infértiles. No obstante, algunas razas de ovinos homocigotas tienen tasas ovulatorias y prolificidad altas.Implicaciones: las mutaciones en los genes de fecundidad relacionadas con tasa ovulatoria y prolificidad, representan una gran utilidad en la implementación de programas de mejoramiento genético, paramejorar la eficiencia reproductiva y rentabilidad de los rebaños.Conclusiones: estos genes de la fecundidad participan en la proliferación, crecimiento y diferenciación de las células de la teca y granulosa, favorecen la esteroidogénesis en las células de la granulosay son fundamentales en la foliculogénesis a nivel ovario. Los genotipos heterocigotos aumentan tasa ovulatoria y prolificidad, pero las ovejas homocigotas son infértiles; sin embargo, en algunas razas, el genotipo homocigoto es fértil y con tasas ovulatoria y de prolificidad altas.

The high climatic variability of hot climates of the intertropical zone reduces cattle fertility. In dairy cows in temperates zones, the THI has been used to evaluate the temperature and relative humidity (RH) joint effect in reproduction, but its use is not recommended in all geographic zones; in hot climates, the maximum temperature (Tmax) can provide more convenient information than THI. The objective of this study was to determine the artificial insemination (AI) service seasons and their joint effect with the maximum temperature and relative humidity of the previous seven days, the service day, and posterior seven days to the AI in the tropical milking criollo (LT) heifer’s gestation. Climatic data was used to define three seasons: hot-dry (HD), hot-humid (HH), and fresh-dry (FD), and 313 artificial insemination services from 176 heifers were analyzed over fourteen years. The seasons were determined by cluster analysis. Gestation at first service (GF) was analyzed with a logistic regression model and global gestation (GG) with a mixed linear generalized model. The Tmax of previous seven days insemination $$ \hat{\beta}1= $$ − 0.20 ± 0.09 (p ≤ 0.02) in HD (p ≤ 0.02) and RH of seven days posterior insemination $$ \hat{\beta}2 $$ = − 0.08 ± 0.04 (p ≤ 0.04) in HD (p ≤ 0.01) affected GF. No effect of the Tmax and RH on the service day was observed (p > 0.05). The highest GG probabilities were higher than 0.70 in HH and FD, making those seasons the most suitable for inseminating LT heifers.

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.

The effect of climatic factors on ovarian activity and reproductive behavior (RB) was evaluated in 46 Bos indicus cows kept under grazing conditions. Temperature-humidity index (THI) was used as an indicator of stress and divided in alert, damage and emergency levels. Fat thickness (FAT) was taken during the last trimester of gestation (LTG) to approximately 90d postpartum (PP). At 30d PP animals received a progesterone (P4)-releasing device (CIDR) which was withdrawn 9d later. Ovarian activity was assessed by blood progesterone on days 21, 24, 27, 30, 49, 51, and 54 PP. Animals were divided into three groups, higher, and moderate RB and non-behavior. Sixty percent presented a THI >74 increasing dramatically from June to September up to >78. During LTG, animals lost 27% of their body reserves contrasting to PP where an increase of 2.6% (P=0.002) was observed. The percentages of cyclic and non-cyclic animals were 57 and 43%, respectively (P> 0.05). Seventy-two percent displayed RB and 28% were non-behavior (P

This study tested whether the intravenous application of kisspeptin can stimulate the pulsatile secretion of LH in suckling ewes during postpartum anestrus. Ten days after lambing, Pelibuey ewes were allocated among two groups: (1) continuous suckling (n = 8), where the lambs remained with their mothers, and (2) restricted suckling (n = 8), where the mothers suckled their lambs twice daily for 30 min. On Day 19 postpartum, the ewes were individually penned with ad libitum access to water and feed and given an indwelling catheter in each jugular vein. On Day 20, 4 mL of blood was sampled every 15 min from 08:00 to 20:00 h to determine LH pulse frequency. At 14:00 h, four ewes in each group received 120 μg of kisspeptin diluted in 3 mL of saline as a continuous infusion for 6 h, the remaining four ewes in each group received only saline. The interaction between kisspeptin and suckling type did not affect LH pulse frequency (p &gt, 0.05). Before kisspeptin administration, pulse frequency was similar in all groups (1.50 ± 0.40 pulses per 6 h, p &gt, 0.05). With the application of kisspeptin, pulse frequency increased to 3.50 ± 0.43 pulses per 6 h (p ≤ 0.014), so the concentration of LH (1.11 ± 0.14 ng mL−1) was greater in kisspeptin-treated ewes than in saline-treated ewes (0.724 ± 0.07 ng mL−1, p ≤ 0.040). The frequency of LH pulses was greater with restricted suckling than with continuous suckling (2.44 ± 0.29 versus 1.69 ± 0.29 pulses per 6 h, p ≤ 0.040). We conclude that intravenous application of kisspeptin increases the pulsatile secretion of LH in suckling ewes and that suckling might reduce kisspeptin neuronal activity, perhaps explaining the suppression of ovulation. Moreover, the effects of kisspeptin and suckling on pulsatile LH secretion appear to be independent, perhaps operating through different neural pathways.

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

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.

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.

To evaluate the response of the “male effect” and “temporary weaning” on the synchronization of post-partum ovarian activity in Pelibuey ewes, an experiment was carried out using 78 Pelibuey ewes with suckling lambs. The ewes were separated from their offspring for 48 hours and randomly assigned to one of four treatments derived from the arrangement of two factors, “male effect” and “temporary weaning”, each at two levels. Treatments were: T1 (n = 20) control ewes, without “male effect” and without “temporary weaning”); T2 (n = 19) ewes without “male effect” and with “temporary weaning”; T3 (n = 20) ewes with “male effect” and without “temporary weaning”; and T4 (n = 19), ewes with “male effect” and with “temporary weaning”. The response to oestrus, return to oestrus, gestation rate and lambing rate were analysed using logistic regression. The onset of oestrus was analysed using survival curves. No significant differences were found for lambing rate and prolificacy among treatments. “Temporary weaning” (T2) and “male effect” (T3) did not influence the response to oestrus, rate and duration of return to oestrus, or gestation rate and fertility, and was similar to the control group (T1). The interaction of “male effect” with “temporary weaning” (T4) increased the response to oestrus, reduced the rate and duration of return to oestrus, and the gestation rate, but increased fertility. Synchronizing post-partum ovarian activity with “male effect” and “temporary weaning” reduces the onset of oestrus and the rate of return to oestrus, but increases the response to oestrus and fecundity in Pelibuey ewes.Keywords: Biostimulation, progestogens, prolificacy, prostaglandins, suckling

Post-partum anestrus is a problem on farms, and its duration depends on the frequency and intensity of suckling which affects reproduction and production efficiency to become a determining economic factor. The aim of this study was to determine the post-partum reproductive response in ewe to a "male effect" with an ovulation induction protocol of five days using progesterone and the application of a metabolic restorative (MR; Metabolase ®). One hundred and twenty females were randomly assigned to one of four treatments: T1: Continuous suckling (CS; n = 29), T2: CS + MR (n = 29), T3: CS + Male Effect (ME; n = 32), and T4: CS + MR + ME. The percentage of females in ovulation, weight changes among females and lambs, the onset of estrus, calving, fecundity, and prolificacy were also determined. The ovulation percentage was higher in CS + ME and CS + MR + ME (75.0 and 73.3%) than in the other treatments. Weight changes in females and lambs were different among periods. The onset of estrus was similar for CS and CS + MR (25.9 ± 1.9 and 25.7 ± 0.7 h, respectively). The calving percentage was higher for CS + MR (86.2%) than other treatments. Male presence positively affected the postpartum cyclic ovarian re-establishment and the metabolic restorative could even improve the fertility of hair ewes in continuous suckling with similar hormone protocol Keywords : Male effect, metabolic stimulation, post-partum anestrus

En este estudio se analizó la respuesta reproductiva de las ovejas de pelo al efecto del amamantamiento y a un protocolo de sincronización posparto (PP) con hormonas, así como el efecto del carnero. Aisladas de los carneros, 96 ovejas fueron clasificadas aleatoriamente al parto en dos grupos (n=48): un primer grupo con amamantamiento continuo por 18 horas (Ac) y un segundo grupo de lactancia controlada con amamantamiento por 30 min 2 veces día-1 (Lc). En el día 35 PP se les colocó a las ovejas un CIDR (Controlled Internal Drug Release) por 10 días, 48 horas antes de retirarlo se les aplicó 7,5 mg de dinoprost y se probó el efecto del carnero (Ca) 48 h antes y al momento de retirar el CIDR. Se determinó el contenido de progesterona (P4) por RIA a los 30, 35, 50, 55 y 64 días PP. Las ovejas fueron inseminadas vía intrauterina con laparoscopio abdominal 12 a 15 horas después de iniciado el estro. Las variables de respuesta fueron: porcentaje de ovulación antes de los 35 días PP, hora de inicio del estro, tasa de gestación, prolificidad, fecundidad y pesos de las ovejas y sus crías. La información obtenida fue analizada mediante regresión logística y de Poisson, prueba de chi cuadrado, curvas de supervivencia y análisis de medidas repetidas. El porcentaje de ovejas que ovularon antes de los 35 días PP fue mayor (p0,05) entre tratamientos. El peso de los corderos fue mayor (p

To evaluate the use of equine follicular fluid (EFF) in a single-reduced dose on the synchronisation of oestrus in Boer×Nubian goats, the following experimental treatments were applied: Goats in group T1 (FGA, n=10) were synchronised in oestrus by intravaginal sponges impregnated with 45 mg FGA (Chronogest-MSD) for 12 days; group T2 (T2, FGA + eCG, n=16) goats were synchronised as in T1, plus 400 IU eCG, 48 h before sponge withdrawal; T3 goats (FGA + PGF2α, n=11) received the sponge as T1 plus an i.m. dose of PGF2α (1 ml, Prosolvin-MSD) 48 h before sponge withdrawal; T4 (FGA + EFF, n=19) animals received the sponge as T1 plus 2 ml EFF at sponge withdrawal and finally, group T5 (FGA + PGF2α + EFF, n=10) was like T3 plus 2 ml EFF at sponge withdrawal. Presentation: onset and duration of oestrus were recorded, and fertility, prolificacy and fecundity were calculated. All females showed oestrus. The onset of oestrus was different (P < 0.01), T4 and T5 goats showing a delay (50.5±4.9 and 48.2±2.0 h for T4 and ...

Grazing behavior, diet selection and weight gain of heifers (with or without social models) were assessed in an unfamiliar site containing high plant diversity. The study was performed within a tropical forest ecosystem containing a mixture of grass forb/herb, shrub and tree species. Ten inexperienced crossbred Bos taurus × Bos indicus heifers (7 ± 1 months old) were randomly assigned to one of two groups: naive or naive + social model (sm) and two experienced heifers (16 months old) were assigned to the second group. Naive heifers were bottle-nursed from days 2 to 90 after birth and began grazing at 1 month of age in tropical grass monocultures, while experienced animals had been foraging in sites containing a high diversity of plant species for 3 months prior to the study. Each group grazed in separate paddocks for a 12-week period during the rainy season, and animals were observed using focal sampling from 7:00 to 19:30 h to assess diet composition based on bite counts. Weight gain was assessed every 14 days. Paddocks contained from 1481 to 1789 kg/ha of herbaceous dry matter, enough to support the heifers throughout the study without affecting diet selection. Shrub and tree cover ranged from 55.2 to 58.4% across treatments. Bites per minute were adjusted to a log-scaled quadratic-plateau model and the curves showed no differences between treatments (P = 0.756). However, diet composition differed between groups (P

Con la finalidad de estudiar si la administración de la Somatotropina Bovina Recombinante (bST) dos días antes del retiro del progestágeno, tiene efecto en la sincronización de estros, inicio del estro, fertilidad, prolificidad y tipo de parto en ovejas Pelibuey, a 180 ovejas de 4,0 ± 0,32 años de edad, se les inserto un dispositivo intravaginal impregnado con progesterona (CIDR P4 0,3 g), por nueve días. Dos días antes del retiro del dispositivo, las ovejas se asignaron aleatoriamente a uno de tres tratamientos: T1 = CIDR(n=60); T2= CIDR+ 250 mg de bST (n= 60) y T3= CIDR+300 UI eCG 48 horas antes del retiro del progestágeno (n= 60). La respuesta en la sincronización de estros, fertilidad y prolificidad no fue diferente (p>0,05) entre tratamientos. el tiempo a inicio del estro fue menor (p

Se realizaron dos exp erimentos con la nalidad 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 cuerp os lúteos, fertilidad, parición, fecundidad y prolicidad. En el primer exp erimento se utilizaron 125 hembras asignadas al azar a uno de o cho 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 exp erimento se utilizaron 178 hembras asignadas al azar a uno de los siguientes tratamientos. P (T1; 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 eciencia reproductiva de las ovejas Pelibuey.

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 × 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 conPNDR (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.

Las ovejas originarias de latitudes tropicales, como la Pelibuey, pueden ovular continuamente, pero se desconoce si esa actividad continúa a mayores latitudes. Ovejas Pelibuey continuas (grupo 1, n=15) y estacionales (grupo 2, n=15) fueron expuestas durante 90 d (21 de diciembre de 2002 al 21 de marzo de 2003) a un fotoperiodo inhibitorio (16hL/8hO), similar al de latitudes altas (56°), utilizando una cámara de luz controlada. La actividad ovárica se evaluó mediante la concentración plasmática de progesterona en muestras tomadas dos veces por semana, desde una semana antes de la aplicación del fotoperiodo hasta dos meses después de concluir el tratamiento. Se comparó el número de días con actividad ovulatoria (prueba de t) y el porcentaje de hembras con actividad ovulatoria ( #967;2) entre ambos grupos. Las ovejas mantuvieron su actividad durante 75.5+11.8 y 73.3+13.6 d para los grupos continuas y estacionales (p0.05). Hubo anestro en 60% del grupo continuo y 66.6% del grupo estacional (p0.05). Se concluye que las ovejas Pelibuey seleccionadas como continuas no son sensibles a los cambios del fotoperiodo en una latitud de 19° N. Sin embargo, al exponerlas a un fotoperiodo más amplio, activan el mecanismo neuroendocrino que controla el anestro estacional.

Se estudió el efecto del amamantamiento retrasado sobre la ganancia de peso pre-destete (GDP) y consumo de leche (CL) de becerros, así como el efecto en la duración del periodo parto-primera ovulación (IPPO), número total de folículos (NTF), diámetro (DF), tamaño (TF) y tasa de crecimiento (TC) del folículo de mayor tamaño, producción de leche (PL) y cambios de peso corporal (CPC) de las vacas durante 100 días posparto. Treinta vacas con su becerro en un sistema de doble propósito fueron repartidas aleatoriamente en tres modalidades de amamantamiento: tradicional (AT), controlado (LC) y retrasado (AR). Las vacas en AT y AR fueron ordeñadas a fondo en los cuatro cuartos de la ubre y a las vacas en LC solo se ordeñaron tres. Terminado el ordeño, los becerros en AT permanecieron con su madre por 8h, mientras que en LC y AR lo hicieron por 30min u 8h postordeño, respectivamente, antes de separarlos. La GDP fue similar en AR y AT (p0,05) pero menor que AT (p0,05) excepto para PL total. Las vacas AR produjeron 3,2kg/día de leche más que LC (p0.05), but fewer did in group AT (P0.05) except for total PL. Cows in AR produced 3,2kg/day more milk than LC (P0,05) mas menor que AT (p0,05) exceto para PL total. As vacas AR produziram 3,2kg/dia de leite mais que LC (p