Examinando por Materia "Reproductive performance"

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Ecological aspects of three strains of entomopathogenic nematodes from the department of Lambayeque-Peru
(Cairo Egyptian Society for Biological Control of Pest, 2024-09-06) Rodas Adrianzén, Jennifher Elizabeth; Cueva Dávila, Raúl Samuel; Pérez Tesén, Edgar Darwin; Calderón Arias, Carmen Patricia; Chávez Cabrera, Alexander
Background Entomopathogenic nematodes (EPN) are used as a biological control agent for diferent insect pests in agriculture. The genera Heterorhabditis and Steinernema are the most used commercially. For an EPN species to be used as a biological controller, it is necessary to know its ecological aspects, including reproductive potential, movement capacity, and mean lethal concentration (LC50). These aspects were evaluated in three EPN strains isolated in Galleria mellonella larvae collected in the Lambayeque-Peru region, to determine if they are promising as biological controllers. The strains of EPN studied are Heterorhabditis sp. (PC9 strain), H. bacteriophora Poinar (PM10 strain), and Steinernema diaprepesi Nguyen y Duncan (SV19 strain). Results Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) had high production of infective juveniles (IJs): 217.750 and 186.800, respectively, while S. diaprepesi (SV19 strain) only reached 84.150 IJs. The movement capacity of Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) reached a depth of 15 cm to parasitize G. mellonella larvae, while S. diaprepesi (SV19 strain) only reached 10 cm. In decreasing order, the LC50 value of S. diaprepesi (SV19 strain), Heterorhabditis sp. (PC9 strain) and H. bacteriophora (PM10 strain) were: 24.03, 13.74, and 8.19 IJs/ml, respectively. Conclusions Heterorhabditis sp. PC9 and H. bacteriophora PM10 are promising a biological control agent because they present great production of IJs, great displacement capacity, and high pathogenicity against G. mellonella. Additionally, both strains present a mixed search strategy or seeker-hunter (seeker-browser).
Evaluación de índices productivos en ovinos de la raza Dhone Merino para la generación de núcleos de reproductores en la sierra sur
(Universidad Nacional Micaela Bastidas de Apurímac (UNAMBA), 2014-10-10) Gonzáles Castillo, Mario Lino; Huanca Mamani, Teodosio; Cárdenas Minaya, Oscar Efraín; Mamani, R.; Sapana Valdivia, Rómulo
En el Perú, la crisis en la crianza de ovinos y la disminución de su población a 9 523 200, se debe fundamentalmente al colapso del precio internacional de la lana y a la falta de dinamismo de los criadores de ovinos para reorientar los sistemas de producción de acuerdo a las necesidades de las tendencias del mercado. La baja rentabilidad de la lana resultó en dos tipos de consecuencias sobre el mercado de carne ovina. Por un lado, se registró una reducción importante de la población ovina de los principales países exportadores de carne ovina (Australia, Nueva Zelanda, Uruguay) y por otro, ha venido ocurriendo una mayor especialización carnicera en los sistemas laneros, mejorando los índices de producción de carne, sobre todo en el rubro carne de cordero (Salgado, 2000). El ovino Dohne Merino sintético de doble propósito introducido, fue desarrollado por el Departamento de Agricultura de Sud África usando ovejas Merino Peppin y carneros Merino Alemán de Carne. Las progenies fueron seleccionadas por alta fertilidad, rápida tasa de crecimiento de los corderos y lana fina de 19 a 22 micras de alta calidad, haciendo del Dohne Merino un productor de carne altamente eficiente (Cabaña Tres Árboles. 2005). El objetivo del presente estudio es el de evaluar los índices productivos de los ovinos de la raza Dhone Merino para la generación de Núcleos de Reproductores en condiciones de la región de Puno.
Use of seminal plasma to improve reproductive performance in alpacas (Vicugna pacos) following natural mounting
(CSIRO Publishing, 2016-01) Huanca, Wilfredo; Turin Vilca, Jesús Enrique; Mamani, Camilo; Sanchez, R.; Huanca, Willian Fahrid; Huanca Mamani, Teodosio
Alpacas are classified as induced ovulators, and an external stimulus is required for the occurrence of ovulation. The seminal plasma (SP) of camelids contains a protein identified as ß nerve growth factor with the capacity to induce ovulation and corpus luteum formation. Alpacas have a poor reproductive efficiency and high embryo mortality rate. A study was designed to evaluate the use of SP to improve reproductive performance post natural mating (Exp. 1) and with different mounting time (MT; Exp. 2). Experiment 1: Nonpregnant alpacas (n = 117) exhibiting a dominant follicle = 7 mm, detected by transrectal ultrasonography, were bred by natural mating and then assigned randomly to 1 of 3 treatments: T1 (n = 40), 1 mL of SP IM; T2 (n = 39), 1 mL of GnRH analogue (0.0042 mg of buserelin acetate), IM; and T3 (n = 38), control. Experiment 2: Nonpregnant alpacas (n = 180) exhibiting a follicle = 7 mm were assigned randomly to the following treatments: T1 (n = 30): MT 5 min; T2 (n = 30): MT 5 min + 1 mL of SP; T3 (n = 30): MT 10 min; T4 (n = 30): MT 10 min + 1 mL of SP; T5 (n = 30): MT > 15 min; T6 (n = 30): MT > 15 min + 1 mL of SP. The same male was used for mating females in T1 and T2, T3 and T4, and T5 and T6, respectively. Animals were evaluated by ultrasound with an Aloka SSD 500 (Aloka, Tokyo, Japan) and 5.0-MHz linear transducer on Day 25 for pregnancy diagnosis. In Exp. 1 the conception rate was 67.5, 51.3, and 55.3% for T1, T2, and T3, respectively (P > 0.05). In Exp. 2 the conception rate was 46.2, 67.9, 57.1, 73.3, 61.8, and 72.7% for T1, T2, T3, T4, T5, and T6 (P < 0.05) and was significantly different between T1 v. T2 and T3 v. T4. The results suggest that the use of SP could be one method to improve reproductive performance in alpacas.