The aim of this research was to model the lactation curve in dairy cows with nonlinear models (MNL) and nonlinear mixed models (NLMM), in an intensive breeding dairy farm during the period 2007-2013. In total, 22 173 data referred to biweekly milk production controls were analysed, corresponding to 1302 lactations and 668 Holstein cows. The Brody, Wood, Cobby and Wilmink mathematic models were used evaluating NLM and NLMM, considering the cow as a random effect using SAS v. 9.4 statistical package. Applying information from Akaike (AIC) and Bayesian (BIC) method, NLMM was found to be the best fit for the 305-day lactation curve. Wood mixed model was the best fit for the first calving and Wilmink mixed model for the other calvings. Likewise, production peak, days to production peak, percent productive yield by thirds during the lactation period and production at 305 days according to...

The aim of this research was to model the lactation curve in dairy cows with nonlinear models (MNL) and nonlinear mixed models (NLMM), in an intensive breeding dairy farm during the period 2007-2013. In total, 22 173 data referred to biweekly milk production controls were analysed, corresponding to 1302 lactations and 668 Holstein cows. The Brody, Wood, Cobby and Wilmink mathematic models were used evaluating NLM and NLMM, considering the cow as a random effect using SAS v. 9.4 statistical package. Applying information from Akaike (AIC) and Bayesian (BIC) method, NLMM was found to be the best fit for the 305-day lactation curve. Wood mixed model was the best fit for the first calving and Wilmink mixed model for the other calvings. Likewise, production peak, days to production peak, percent productive yield by thirds during the lactation period and production at 305 days according to...

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Con el objetivo de comparar el rendimiento de raíces reservantes, se evaluaron ocho clones de yuca (Manihot esculenta, Crantz), bajo las condiciones de suelo y clima de Iquitos. El experimento se llevó a cabo en un Diseño de Bloques al Azar, en el Campo Experimental Agrícola de la Facultad de Agronomía-UNAP, ubicado en Zúngaro Cocha a 25 km. al S.O. de la ciudad de Iquitos. De acuerdo a los resultados obtenidos se concluye que el clon "Amarilla" fue el más rendidor, seguido de los clones Z2-82 y "Zevallo negro", demostrando alta capacidad de producción.

Con el objetivo de comparar el rendimiento de raíces reservantes, se evaluaron ocho clones de yuca (Manihot esculenta, Crantz), bajo las condiciones de suelo y clima de Iquitos. El experimento se llevó a cabo en un Diseño de Bloques al Azar, en el Campo Experimental Agrícola de la Facultad de Agronomía-UNAP, ubicado en Zúngaro Cocha a 25 km. al S.O. de la ciudad de Iquitos. De acuerdo a los resultados obtenidos se concluye que el clon "Amarilla" fue el más rendidor, seguido de los clones Z2-82 y "Zevallo negro", demostrando alta capacidad de producción.

The aim of this study was to determine the effect of age at first calving (AFC) on the standardized production of milk (SMP) of the first and second lactation and interval between the first two calvings (CI) in Holstein cows of the Lima region, Peru. Records of 4215 cows from nine farms, registered in the Dairy Productivity Service of the National Agrarian University La Molina, between January 2003 and December 2012 were analysed. The information was analysed through descriptive statistics and by a mixed linear model, using SAS 9.4. The average AFC was 24.9 ± 2.3 months. The AEPP influenced on the SMP (p=0.0008), but not in the IEP (p=0.3969). Likewise, significant differences were found (p<0.01) between the two lactations, between the four seasons of the year and between the 10 years evaluated for the two variables under study. In conclusion, higher SMP and lower CI were observed at...

The aim of this study was to determine the effect of age at first calving (AFC) on the standardized production of milk (SMP) of the first and second lactation and interval between the first two calvings (CI) in Holstein cows of the Lima region, Peru. Records of 4215 cows from nine farms, registered in the Dairy Productivity Service of the National Agrarian University La Molina, between January 2003 and December 2012 were analysed. The information was analysed through descriptive statistics and by a mixed linear model, using SAS 9.4. The average AFC was 24.9 ± 2.3 months. The AEPP influenced on the SMP (p=0.0008), but not in the IEP (p=0.3969). Likewise, significant differences were found (p<0.01) between the two lactations, between the four seasons of the year and between the 10 years evaluated for the two variables under study. In conclusion, higher SMP and lower CI were observed at...

La Donovanosis es una enfermedad ulcerativa crónica y progresiva que ataca por lo común la región genital, es producida por el Calymmatobacterium granulomatis, bacteria Gram negativa. La Azitromicina ha emergido como la droga de elección para su tratamiento. Se presenta un caso de Donovanosis en un varón de 46 años, quien tenía relaciones heterosexual y homosexual, el cuál presento papula anal que evoluciono a una úlcera crónica, le realizan el diagnostico de tumoración anorrectal a descartar una neoplasia anorrectal y le realizan colostomía. El retardo en la sospecha clínica en un área no endémica concluyo con su diagnóstico con un extendido en lámina para microscopia con coloración Giemsa.

The pustulose ark, Anadara tuberculosa, is considered as an emblematic species of the east Pacific mangrove ecosystem. The decline of its populations is of increasing preoccupation, in particular in Peru. The use of hatchery-produced larvae for stock enhancement or aquaculture is attractive but raises strong criticisms from an ecological point of view, as it could conduce to loss of genetic diversity in wild populations and favor the disease spreading from hatcheries to the environment. In this works, spat production through traditional aquaculture/biotechnology technologies was associated with pathogen molecular diagnostics and with genetic diversity estimation to produce specific pathogen-free (SPF) larvae from genetically characterized populations. All PCR and nested-PCR diagnostics of common bivalve pathogens, such as Bonamia, Martelia, Perkinsus and OsHV1, led to negative results fo...

The aim of this study was to determine the antimicrobial resistance of 176 Escherichia coli strains isolated from broiler chicken organs. The strains were challenged with beta-lactam, quinolones and fluoroquinolones, observing resistance to beta-lactam antibiotics (97.7%) and quinolones (86.7%). The results showed that 71.6% of the isolates phenotypically expressed the production of extended spectrum beta-lactamases (ESLB). By PCR, resistance genes for beta-lactams blaTEM, blaSHV, blaCTX-M1 and Amp-C and resistance genes for quinolones qnrA, qnrB, qnrS were determined. The genes Amp-C (74%), blaCTX-M (65%), blaSHV (65%), blaTEM (50%), qnrB (86.4%) and qnrS (11.9%) were found. The qnrA gene was not evident in the samples analysed. The results obtained revealed a large percentage of resistance to the studied antibiotics and the presence of resistance genes in isolates from poultry for huma...

The aim of this study was to determine the antimicrobial resistance of 176 Escherichia coli strains isolated from broiler chicken organs. The strains were challenged with beta-lactam, quinolones and fluoroquinolones, observing resistance to beta-lactam antibiotics (97.7%) and quinolones (86.7%). The results showed that 71.6% of the isolates phenotypically expressed the production of extended spectrum beta-lactamases (ESLB). By PCR, resistance genes for beta-lactams blaTEM, blaSHV, blaCTX-M1 and Amp-C and resistance genes for quinolones qnrA, qnrB, qnrS were determined. The genes Amp-C (74%), blaCTX-M (65%), blaSHV (65%), blaTEM (50%), qnrB (86.4%) and qnrS (11.9%) were found. The qnrA gene was not evident in the samples analysed. The results obtained revealed a large percentage of resistance to the studied antibiotics and the presence of resistance genes in isolates from poultry for huma...

Spherical titanium barium nanoparticles with an average size about 100 nm in the tetragonal crystal phase were obtained by peroxide synthesis. To prevent their agglomeration and reduce the toxic effect, the surface of nanoparticles was chemically modified with sodium oleate and chitosan. Influence of surface modification by these compounds on agglomeration of nanoparticles in aqueous solutions, their spectral features, as well as generation of the second optical harmonic were investigated.