Caudal vena cava thrombosis in a dairy cow (Bos taurus) in Argentina

Caudal vena cava thrombosis (CVCT) is an acute disease secondary to ruminal lactic acidosis and rumenitis with fatal outcome in cattle fed with a high-grain diet. The aim of this paper is to describe CVCT in an adult Holstein cow from a herd in Balcarce, Buenos Aires, Argentina. Clinical signs included dyspnea, weakness, recumbence, and hemoptysis, followed by death in 3.5 days. Important necropsy findings included multiple hepatic abscesses, a septic thrombus (4.0cm x 2.0cm) in the vena cava adjacent to the liver, and a 15cm hematoma in the right lung. Histological lesions observed in the pulmonary parenchyma included suppurative pneumonia with embolic bacterial colonies and severe interstitial fibroplasia. Dissociation and degeneration of elastic fibers were observed in the pulmonary arteries, and necrotizing vasculitis was present in the caudal vena cava. We concluded that CVCT should be included in the differential diagnosis of diseases with acute respiratory signs. The preventive measures to control the CVCT include the reduction of lactic acidosis.EEA BalcarceFil: Schild, Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Instituto Nacional de Investigación Agropecuaria (INIA). La Estanzuela; UruguayFil: Armendano, Joaquín Ignacio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Universidad Nacional de Mar Del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Liboreiro, Matías. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Profesional de la Actividad Privada; ArgentinaFil: Bresky, Florencia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Morrell, Eleonora Lidia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odriozola, Ernesto Raul. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Canton, German Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentin

Controlling Endemic Neospora caninum-Related Abortions in a Dairy Herd From Argentina

After diagnosis of endemic abortions due to neosporosis in a commercial dairy farm, routes of Neospora caninum-transmission were evaluated in order to choose the best strategy for reducing its seroprevalence and related abortions. Fifty two dam-calf pairs were bled at parturition. Additionally, 22 female calves were also sampled at regular 3 month intervals until 18–22 months. N. caninum specific antibodies were assayed by IFAT. Serum samples were tested at a dilution 1:25 for calves before colostrum intake and heifers before mating and 1:100 for multiparous cows. Only serum samples from IFAT seropositive cattle involved in the evaluation of the routes of transmission were assessed by a commercial IgG avidity ELISA. Seropositive cows or heifers were artificially inseminated with semen from Hereford bulls. The progenies from these female animals were sent to a feed lot to produce meat. Different generalized linear models (GLM) were used to study the relationship between abortion, age category, and serostatus. Seropositive heifers were more likely to have a record of abortion (OR 2.7; 95% CI 1.6–4.7). Vertical transmission frequency was 55.5% (5 seropositive calves/9 seropositive cows). Horizontal transmission was 22.7% (5 female calves seroconverted at least one time/22 females calves sampled during 24 months) and these 5 female calves had low avidity. In heifers, both seroprevalence and abortion rates decreased from 22.1 and 8.4% of 475 in 2009 to 6.1 and 4.3% of 578 in 2015, respectively (p < 0.01). Over 5 years, N. caninum-seroprevalence and the related abortions in heifers decreased after the control strategy was assessed.Fil: Lagomarsino, H.. No especifíca;Fil: Scioli, Agustín. No especifíca;Fil: Rodríguez, Alejandro. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Fiorani, Franco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Bence, Ángel. Universidad Nacional del Centro de la Provincia de Buenos Aires; ArgentinaFil: García, Joaquín. No especifíca;Fil: Hecker, Yanina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gual, Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Cantón, Germán. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odeón, Anselmo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Campero, Carlos Manuel. No especifíca;Fil: Moore, Dadin Prando. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; Argentin

Controlling endemic Neospora caninum-related abortions in a dairy herd from Argentina

After diagnosis of endemic abortions due to neosporosis in a commercial dairy farm, routes of Neospora caninum-transmission were evaluated in order to choose the best strategy for reducing its seroprevalence and related abortions. Fifty two dam-calf pairs were bled at parturition. Additionally, 22 female calves were also sampled at regular 3 month intervals until 18–22 months. N. caninum specific antibodies were assayed by IFAT. Serum samples were tested at a dilution 1:25 for calves before colostrum intake and heifers before mating and 1:100 for multiparous cows. Only serum samples from IFAT seropositive cattle involved in the evaluation of the routes of transmission were assessed by a commercial IgG avidity ELISA. Seropositive cows or heifers were artificially inseminated with semen from Hereford bulls. The progenies from these female animals were sent to a feed lot to produce meat. Different generalized linear models (GLM) were used to study the relationship between abortion, age category, and serostatus. Seropositive heifers were more likely to have a record of abortion (OR 2.7; 95% CI 1.6–4.7). Vertical transmission frequency was 55.5% (5 seropositive calves/9 seropositive cows). Horizontal transmission was 22.7% (5 female calves seroconverted at least one time/22 females calves sampled during 24 months) and these 5 female calves had low avidity. In heifers, both seroprevalence and abortion rates decreased from 22.1 and 8.4% of 475 in 2009 to 6.1 and 4.3% of 578 in 2015, respectively (p < 0.01). Over 5 years, N. caninum-seroprevalence and the related abortions in heifers decreased after the control strategy was assessed.EEA BalcarceFil: Lagomarsino, Horacio. Actividad privada; ArgentinaFil: Scioli, Agustín. Actividad privada; ArgentinaFil: Rodríguez, Alejandro. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Armendano, Joaquín. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Fiorani, Franco. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Bence, Ángel. Universidad de Buenos Aires. Facultad de Ciencias Veterinarias; Argentina.Fil: García, Joaquín. Actividad privada; ArgentinaFil: Hecker, Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Gual, Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Cantón, Germán. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odeón, Anselmo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce, ArgentinaFil: Campero, Carlos. Actividad privada; ArgentinaFil: Moore, Dadín. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Effect of Dexamethasone in Neospora Caninum Seropositive Calves

The aim of this study was to evaluate the effect of Dexamethasone (DXM) on clinical parameters, absolute and differential leukocyte count, specific IgG titers, IFN-γ production and parasitemia in beef calves seropositive to Neospora caninum. Fifteen calves were assigned to four experimental groups as follow: group A: 4 sero- positive calves treated with DXM; group B: 4 seropositive calves without DXM; group C: 3 seronegative calves treated with DXM, and group D: 4 seronegative calves without DXM treatment. The absolute leukocyte count was higher in both groups A and C in the 3rd day after the first dose of DXM mainly due to a significant neutrophilia (p0.05). Similarly, IFN-γ levels did not change among experimental groups (p>0.05). DNA was de- tected in calves from groups A and B at 7 Days Post Administra- tion (dpa) and from group A at 14 dpa. Even when DXM adminis- tration induced hemotological parameter changes, no reactivation of Neospora-infection was observed according to specific IgG titers and presence of the parasite on leukocytes in naturally seropositive beef male calves.Fil: Idarraga Bedoya, S.. Universidad Nacional de Mar del Plata; ArgentinaFil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata; ArgentinaFil: Gual, Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata; ArgentinaFil: Hecker, Yanina Paola. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Leunda, M. R.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Pereyra, S.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Verna, Andrea Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Campero, C. M.. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Buenos Aires Sur. Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Odeón, Anselmo Carlos. Universidad Nacional de Mar del Plata; ArgentinaFil: Moore, Dadin Prando. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Effect of dexamethasone in Neospora Caninum seropositive calves

The aim of this study was to evaluate the effect of Dexamethasone (DXM) on clinical parameters, absolute and differential leukocyte count, specific IgG titers, IFN-γ production and parasitemia in beef calves seropositive to Neospora caninum. Fifteen calves were assigned to four experimental groups as follow: group A: 4 sero- positive calves treated with DXM; group B: 4 seropositive calves without DXM; group C: 3 seronegative calves treated with DXM, and group D: 4 seronegative calves without DXM treatment. The absolute leukocyte count was higher in both groups A and C in the 3rd day after the first dose of DXM mainly due to a significant neutrophilia (p0.05). Similarly, IFN-γ levels did not change among experimental groups (p>0.05). DNA was de- tected in calves from groups A and B at 7 Days Post Administra- tion (dpa) and from group A at 14 dpa. Even when DXM adminis- tration induced hemotological parameter changes, no reactivation of Neospora-infection was observed according to specific IgG titers and presence of the parasite on leukocytes in naturally seropositive beef male calves.Fil: Idarraga-Bedoya Samuel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Armendano Joaquin Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Gual, Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Hecker Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Leunda María Rosa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Pereyra Susana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Verna Andrea Elizabeth. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Campero Carlos Manuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Odeon Anselmo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Moore Dadin Prando. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina

Delayed type hypersensitivity induced by intradermal inoculation of a Neospora caninum tachyzoite antigen in previously exposed cattle

The aim of this study was to evaluate delayed type hypersensitivity (DTH) induced by the intradermal inoculation of a Neospora caninum tachyzoite soluble lysate in cattle previously exposed with the protozoa. Four experimental groups were selected according to the prior exposure to N. caninum antigen. All cows were intradermally injected with a N. caninum tachyzoite soluble lysate and skinfold thickness growth at the inoculation sites was measured at 0, 24, 48, 72 and 96 h post inoculation (hpi). Additionally, specific antibodies and IFN-γ production were assessed. Cows experimentally infected with live N. caninum tachyzoites and cows naturally exposed to N. caninum developed skin reactions compatible with DTH between 24 and 96 hpi (p  0.05). Furthermore, serological status of the animals was not modified due to the intradermal inoculation. The highest IFN-γ production was observed at 15 days after intradermal inoculation (p < 0.05). Therefore, these results suggest that cattle previously exposed to N. caninum develop a reaction compatible with DTH which could be useful as in vivo cell mediated immunity parameter for assessed bovine neosporosis.EEA BalcarceFil: Fiorani, Franco. Consejo Nacional de Investigaciones Científicas y Técnicas;, ArgentinaFil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Hecker, Yanina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Araoz, Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Canton, German Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Leunda, María Rosa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Pereyra, Susana Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Corva, Pablo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Odeon, Anselmo Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Moore, Prando Dadin. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentin

A comparative study of commercial ELISAs for antibody detection in the diagnostic investigation of Neospora caninum-associated abortion in dairy cattle herds in Uruguay

A pesar de su importancia, el diagnóstico etiológico del aborto en bovinos representa un desafío técnico para los veterinarios clínicos y laboratoristas, en parte debido a la dificultad de recuperar los fetos abortados en condiciones extensivas de campo. Dicha dificultad limita la posibilidad de detectar tempranamente los vientres abortados y de efectuar la investigación patológica y microbiológica de los abortos. Neospora caninum es un protozoario cosmopolita identificado como uno de los principales agentes abortigénicos en bovinos. En este estudio proponemos una aproximación seroepidemiológica para diagnosticar abortos por N. caninum en bovinos lecheros usando kits de ELISA comerciales. Se procesaron muestras de entre 12 y 93 vacas y/o vaquillonas con (casos) y sin (controles) historia reciente de aborto en 4 tambos comerciales de Uruguay. La proporción controles:casos analizados varió entre 1:1 y 4,6:1. Las muestras (n=230) fueron analizadas mediante 3 kits comerciales para la detección de anticuerpos IgG anti-N. caninum. En los 4 tambos la proporción de vacas y/o vaquillonas seropositivas por cualquier kit fue significativamente mayor en los casos respecto de los controles (odds ratio=5,13 a 36; p=0,0002 a 0,0485). La concordancia entre los kits varió de débil a fuerte (coeficiente Kappa de Cohen=0,58 a 0,83). Concluimos que, a pesar de la imperfecta concordancia entre estos kits, el empleo de todos ellos permitió arribar a conclusiones similares respecto de la asociación estadísticamente significativa entre seropositividad a N. caninum y aborto, lo que demuestra la utilidad de estos kits para la aproximación diagnóstica del aborto a nivel poblacional en condiciones de campo.Bovine abortion causes considerable economic losses to the livestock industry worldwide and is of concern for public health and food safety, given that many abortigenic infectious agents of cattle are zoonotic. Despite its importance, the etiological diagnosis of abortion in cattle is challenging both for veterinary practitioners and laboratory technicians, partly due to the difficulty in recovering aborted fetuses under extensive field conditions for pathological and microbiological diagnostic investigation, and in the early identification of aborted dams. Neospora caninum is a cosmopolitan protozoon identified as one of the main abortigenic agents in cattle worldwide. In this study we propose a comparative seroepidemiological approach for the diagnosis of abortion by N. caninum in dairy cattle. Samples from 12 to 93 cows/heifers with and without recent history of abortion (cases and controls) in four commercial dairy farms were tested. The ratio of controls to cases tested varied from 1:1 to 4.6:1. All samples (n=230) were analyzed by three commercial ELISA kits for the detection of anti-N. caninum antibodies. In all four dairy farms, the proportion of seropositive cows and/or heifers per kit was significantly higher in the cases than in the controls (Odds Ratios=5.13 to 36, p=0.0002 to 0.0485). The agreement among the three kits varied from weak to strong (Coheńs kappa coefficients=0.58 to 0.83). We conclude that, despite the imperfect agreement between these kits, all of them allowed to arrive at similar conclusions regarding the statistical association between N. caninum seropositivity and abortion, thus representing a useful tool for the diagnostic approach at the population level under field conditions.EEA BalcarceFil: da Silva Silveira, Caroline. Instituto Nacional de Investigación Agropecuaria. Estación Experimental La Estanzuela; Uruguay.Fil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina.Fil: Moore, Dadín Prando. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Cantón, Germán José. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Argentina.Fil: Macías Riosecoa, Melissa. Instituto Nacional de Investigación Agropecuaria. Estación Experimental La Estanzuela; Uruguay.Fil: Riet Correa, Franklin. Instituto Nacional de Investigación Agropecuaria. Estación Experimental La Estanzuela; Uruguay.Fil: Giannitti, Federico. Instituto Nacional de Investigación Agropecuaria. Estación Experimental La Estanzuela; Uruguay

Evaluation of frequency of antibodies against Toxoplasma gondii, Neospora caninum and Sarcocystis spp. and transmission routes in sheep from Humid Pampa, Argentina

The aim of this study was to describe the frequency of ovine specific antibodies to Toxoplasma gondii, Neospora caninum and Sarcocystis spp. and to estimate different transmission routes of these infections. One hundred and thirty Texel sheep and their 117 Texel lambs were included in the study. Serum samples were tested for antibodies to T. gondii, N. caninum and Sarcocystis spp. using IFAT. Toxoplasma gondii seroprevalence was 10.00% in sheep (IC95%: 4.80-15.20%), being higher in adult sheep (≥12 year) than in younger sheep (OR 1.30; 95% CI, 1.10-1.50). N. caninum and Sarcocystis spp. seroprevalences were 1.54% (IC95%: 0.00-5.70) and 72.09% (IC95%: 67.70-82.70), respectively, with no association between age and seropositivity in sheep (P>0.05). T. gondii seroprevalence in lambs was 4.27% (IC95%: 0.61-7.94). No association between T. gondii serological status in sheep and their lambs was detected (P = 0.07). Two T. gondii and Sarcocystis spp. seropositive lambs were euthanized and T. gondii and Sarcocystis spp. DNA was detected by PCR in their tissues. In conclusion, the increase of T. gondii seropositivity in relationship with sheep age and the lack of association between sheep-lamb serological status, suggest that horizontal infection is the main transmission route in this flock as reported before. Due to the low number of N. caninum-seropositive ewes no assumptions can be done about the impact of this parasite in this flock. According with previous reports, the main transmission route for Sarcocystis spp. in this species in the present study was horizontal.Facultad de Ciencias Veterinaria

White muscle disease in three selenium deficient beef and dairy calves in Argentina and Uruguay

White muscle disease (WMD), nutritional myodegeneration or enzootic muscular dystrophy, is a nutritional condition associated with selenium and/or vitamin E deficiency in ruminants. These elements are constituents of the major body antioxidant systems. Depletion of selenium results in oxidative damage to cardiac and skeletal muscle cells, resulting in myodegeneration and myonecrosis, typical lesions of WMD. Selenium deficiency is common in South America, but WMD is underreported. This research describes clinical, biochemical and pathological findings in two episodes of WMD associated with selenium deficiency in beef and dairy calves in Argentina and Uruguay with concurrent copper deficiency in one of them, which resulted in spontaneous calf mortality. Further studies are necessary to estimate the true incidence and economic impact of clinical and subclinical mineral deficiencies in livestock production systems in the southern cone of South America.Doença do músculo branco (DMB), miodegeneração nutricional ou distrofia muscular enzoótica é uma condição nutricional associada à deficiência de selênio e/ou vitamina E em ruminantes. Esses elementos são constituintes dos principais sistemas antioxidantes do corpo. O esgotamento de selênio resulta em dano oxidativo às células musculares cardíacas e esqueléticas, resultando em miodegeneração e mionecrose, lesões típicas da DMB. A deficiência de selênio é comum na América do Sul, mas a DMB está subnotificada. Este trabalho descreve os achados clínicos, bioquímicos e patológicos em dois surtos de DMB associados à deficiência de selênio em bezerros para carne e leite na Argentina e Uruguai com concomitante deficiência de cobre em um surto, que resultaram em mortalidade espontânea de bezerros. São necessários mais estudos para estimar a verdadeira incidência e impacto econômico das deficiências minerais clínicas e subclínicas nos sistemas de produção pecuária no sul da América do Sul.EEA Cuenca del SaladoFil: Rodriguez, Alejandro Martin. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Cuenca del Salado; ArgentinaFil: Schild, Carlos Omar. Instituto Nacional de Investigación Agropecuaria (INIA), La Estanzuela; UruguayFil: Canton, German Jose. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Riet‐Correa, Franklin. Instituto Nacional de Investigación Agropecuaria (INIA), La Estanzuela; UruguayFil: Armendano, Joaquín Ignacio. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Caffarena, Rubén Dario. Instituto Nacional de Investigación Agropecuaria (INIA), La Estanzuela; UruguayFil: Brambilla, Emilio Cesar. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: García, Juan Agustín. Universidad de la República. Centro Universitario Regional Este; UruguayFil: Morrell, Eleonora Lidia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Poppenga, Robert. University of California at Davis. School of Veterinary Medicine. California Animal Health and Food Safety (CAHFS). Laboratory; Estados UnidosFil: Giannitti, Federico. Instituto Nacional de Investigación Agropecuaria (INIA), La Estanzuela; Uruguay. University of Minnesota. College of Veterinary Medicine. Veterinary Population Medicine Department; Estados Unido

Semen bovino congelado: efecto de su conservación a -80°C

La historia de la criopreservación de semen abarca más de seis décadas. El descubrimiento de la posibilidad de conservar las gametas en nitrógeno líquido sentó las bases de lo que hoy en día se conoce como la industria de la inseminación artificial. Pero, existen ciertas limitantes dado que, a -196ºC, una proporción importante de espermatozoides no sobreviven o pierden alguna de sus funciones. Además, el nitrógeno líquido es costoso y su provisión no está siempre garantizada. Este hecho suele causar inconvenientes dado que la conservación del semen congelado en un termo sin un nivel adecuado de nitrógeno, produce un aumento de la temperatura que puede dañar a los espermatozoides de manera irreversible. Teniendo en cuenta lo expresado, surge la idea de este proyecto cuyo objetivo general es evaluar la conservación del semen congelado en un freezer mecánico a -80°C, como método alternativo al que se basa en la utilización de nitrógeno líquido. Se prevé desarrollar dos secciones experimentales, dotadas cada una de ellas de dos experimentos. A tal fin, se utilizarán 434 dosis de semen congelado en pajuelas, provenientes de ocho toros de razas productoras de carne de origen británico. Al momento del inicio de los estudios, el semen se encontrará almacenado en un termo con nitrógeno líquido a -196ºC. En la Sección Experimental I se estudiará el efecto de la temperatura de conservación (Experimento 1) y de la extensión del período de conservación (Experimento 2). En este experimento se estudiará también la factibilidad de retornar el semen al nitrógeno líquido 48 h antes de su descongelación, a los efectos de facilitar el trabajo a campo. Se evaluarán los siguientes parámetros: motilidad espermática a las horas 0 y 3 posdescongelación, morfología, número de espermatozoides con motilidad progresiva / dosis inseminante, vitalidad espermática, permeabilidad de membrana e integridad acrosomal. En primera instancia, se efectuará una evaluación subjetiva siguiendo la metodología de trabajo que se utiliza de rutina en nuestro laboratorio. Posteriormente, los resultados obtenidos serán corroborados utilizando un sistema de análisis asistido por computación, disponible en la Facultad de Ciencias Veterinarias de la UBA. En la Sección Experimental II se estudiará el efecto de la conservación del semen a -80°C sobre la producción in vitro de embriones, procediendo a evaluar los porcentajes de segmentación al día 2 y de mórulas y blastocistos a los días 6 y 7 a 9, respectivamente (Experimento 3). Por último, con la finalidad de evaluar el comportamiento del semen congelado, conservado a -80ºC en programas de IATF, se inseminarán 200 vaquillonas y se determinará mediante ultrasonografía, el porcentaje de preñez al día 30 posinseminación (Experimento 4).Fil: Simonetti, Ignacio Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Armendano, Joaquín. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Callejas, Santiago Saul. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaFil: Cabodevila, Jorge Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias; ArgentinaJornadas de Investigación y Posgrado: El desafío de visibilizar la CienciaTandilArgentinaUniversidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinaria