Guillermo Meglia | Universidad Nacional de La Pampa (original) (raw)
Papers by Guillermo Meglia
Fixed-time artificial insemination in beef cattle using CIDR-B devices, progesterone and estradiol benzoate
Theriogenology, 1999
Effects of feeding intensity during the dry period on leukocyte and lymphocyte sub-populations, neutrophil function and health in periparturient dairy cows
Veterinary Journal, May 1, 2005
The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportio... more The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportions of lymphocytes expressing CD4, CD8, WC1, B or IL2R and (3) neutrophil phagocytosis and oxidative burst activity in blood around parturition in three groups of dairy cows fed different levels of a total mixed ration during the last eight weeks before calving. All cows
α-Tocopherol concentration and stereoisomer composition in plasma and milk from dairy cows fed natural or synthetic vitamin E around calving
Mastitis in dairy production, 2005
Immunized Goat with a Conjunctival Vaccine Prevent the Abortus Despite Revaccination with the Same Strain
International Journal of Infectious Diseases, 2022
Journal of Veterinary Medicine, Series B, 2008
Cows with subclinical mastitis caused by Staphylococcus aureus were subjected to subcutaneous inj... more Cows with subclinical mastitis caused by Staphylococcus aureus were subjected to subcutaneous injections with either an extract from the root of Panax ginseng CA Meyer at a dose of 8 mg/kg body weight per day for 6 days, or with saline as a control. The injection areas were checked for adverse reactions. The daily milk production was measured before and after treatment. Blood was collected for total and differential leucocyte counts, identi®cation of lymphocyte subpopulations using¯ow cytometry, lymphocyte proliferation test, and neutrophil phagocytosis and oxidative burst assay. Quarter milk samples were collected for bacteriological analysis and somatic cell counts (SCC). After the end of treatment, the numbers of S. aureus-infected quarters and milk SCC tended to decrease in ginseng-treated cows. Phagocytosis and oxidative burst activity of blood neutrophils were signi®cantly increased 1 week after ginseng treatment, but the proliferative response of blood lymphocytes did not change signi®cantly. The number of monocytes in ginseng-injected cows was signi®cantly higher 1 week post-treatment than pre-treatment, and the number of lymphocytes was signi®cantly higher than pre-infusion at 2 and 3 weeks after ginseng treatment. Similar changes were not observed in the control group. The present ®ndings indicate that ginseng treatment can activate the innate immunity of cows and may contribute to the cow's recovery from mastitis. It is therefore suggested that ginseng has a potential as a stimulator of the immune system of dairy cows.
Valoración de aspectos productivos (carne / lana) en biotipos ovinos característicos de la región norte de La Pampa
Caracterización de las explotaciones lecheras de La Pampa
Ab Intus, Jul 29, 2020
Glándula mamaria y lactación
Efecto de la vacunación conjuntival (REV-1) contra brucelosis en cabras pre-inmunizadas durante el máximo periodo de susceptibilidad a la enfermedad
Ciencia Veterinaria, 2017
Inactivated vaccines of national production, for use in the equine, carried mostly in its formula... more Inactivated vaccines of national production, for use in the equine, carried mostly in its formulation as an adjuvant, aluminum hydroxide Al(OH)3. Nowadays there are new adjuvants potentially superior to the traditional, either with respect to an increase in the time of permanence of the antigen in the host, and the immune response that induce. In the present work was compared the action of adjuvant Emulsigen respect aluminum hydroxide, which were used in a vaccine against equine influenza. For this purpose were established two test models, horses and guinea pigs, and the immune response induced was assessed by means of the determination of antibody titers. The results showed higher titers and extended serum antibodies persistence with the vaccine adjuvanted with Emulsigen, in relation to that adjuvanted with Al(OH)3, likewise were not observed adverse reaction in the site of inoculation.
Ciencia Veterinaria, 2017
La mastitis es una afección de la glándula mamaria que reduce la producción de leche y perjudica ... more La mastitis es una afección de la glándula mamaria que reduce la producción de leche y perjudica notoriamente la calidad composicional y sanitaria de la misma. Las mastitis infecciosas, las más frecuentemente encontradas en tambos comerciales, son producidas, en un 90 % de los casos, por bacterias de los géneros Staphylococcus y Streptococcus. El objetivo de este trabajo fue comprobar el efecto de la utilización de una vacuna a base de Staphylococcus aureus y Streptococcus agalactiae sobre la incidencia de la mastitis producida por estos agentes en vacas lecheras y su producción de leche durante los primeros 4 meses de lactancia. Se trabajó en un tambo de la zona este de La Pampa, con un lote de 62 vaquillonas, de parición de otoño. Las mismas se asignaron aleatoriamente a uno de dos tratamientos: T1 (Control) y T2 (Tratamiento). A lo largo del ensayo se descartaron 6 animales, por causas ajenas al ensayo, de manera que los grupos quedaron conformados por 28 animales cada uno. A las...
Ciencia Veterinaria, 2017
El objetivo de este trabajo fue determinar la evolución de la calidad del agua en establecimiento... more El objetivo de este trabajo fue determinar la evolución de la calidad del agua en establecimientos de la cuenca lechera de La Pampa. Se planteó la hipótesis de que los megatambos, debido a su alto número de animales (400 a 700 vacas), podrían causar una salinización del agua de bebida, por un uso excesivo de las napas, y la contaminación de las mismas, por la gran acumulación de efluentes. Se decidió compararlos con tambos medianos (lOO a 250 vacas) para evaluar el impacto de ambos modelos sobre la calidad del agua. Se trabajó con un total de 8 tambos en cada categoría. Las muestras de agua se obtuvieron semestralmente, durante 3 años consecutivos, y sobre ellas se realizaron análisis químicos (pR, Sales Totales, Dureza, Sulfatos, Cloruros, Nitratos, Nitritos, Amoníaco, Calcio, Magnesio, Flúor y Arsénico) y bacteriológicos. No pudo demostrarse, en ninguno de los dos grupos, un incremento estadísticamente significativo de la salinidad total del agua durante el período de estudio, aún...
Innocuousness and immune response of young bulls vaccinated with S19 either subcutaneously or conjunctival
Blood samples from ten Swedish dairy cows were taken one month before calving, at calving, and on... more Blood samples from ten Swedish dairy cows were taken one month before calving, at calving, and one month after calving. The blood concentration of vitamins A and E, and the trace element selenium (Se) were analysed, as well as the total and differential white blood cell counts,a nd the presenceo f CD62L and CD18 adhesionm oleculeso n blood neutrophils. The levels of vitamins A and E decreased significantly at calving, while whole blood Se increased Leukocytosisw as detectedat calving, explainedm ainly by neutrophilia.T he number of lymphocytest endedt o decreasea t calvrng.T he proportion of CD62L- neutrophilsd ecreased sisnlficantlv at this ttme
Waller K: Changes in some blood micronutrients, leukocytes and neutrophil expression of adhesion ... more Waller K: Changes in some blood micronutrients, leukocytes and neutrophil expression of adhesion molecules in periparturient dairy cows. Acta vet. scand. 2001, 42, 139-150.-Dairy cows are highly susceptible to infectious diseases, like mastitis, during the period around calving. Although factors contributing to increased susceptibility to infection have not been fully elucidated, impaired neutrophil recruitment to the site of infection and changes in the concentrations of some micronutrients related with the function of the immune defence has been implicated. Most of the current information is based on studies outside the Nordic countries where the conditions for dairy cows are different. Therefore, the aim of the study was to evaluate changes in blood concentrations of the vitamins A and E, the minerals calcium (Ca), phosphorous (P), and magnesium (Mg), the electrolytes potassium (K) and sodium (Na) and the trace elements selenium (Se), copper (Cu) and zinc (Zn), as well as changes in total and differential white blood cell counts (WBC) and expression of the adhesion molecules CD62L and CD18 on blood neutrophils in Swedish dairy cows during the period around calving. Blood samples were taken from 10 cows one month before expected calving, at calving and one month after calving. The results were mainly in line with reports from other countries. The concentrations of vitamins A and E, and of Zn, Ca and P decreased significantly at calving, while Se, Cu, and Na increased. Leukocytosis was detected at calving, mainly explained by neutrophilia, but also by monocytosis. The numbers of lymphocytes tended to decrease at the same time. The mean fluorescent intensity (MFI) of CD62L and CD18 molecules on blood neutrophils remained constant over time. The proportion of CD62L + neutrophils decreased significantly at calving. The animals were fed according to, or above, their requirements. Therefore, changes in blood levels of vitamins, minerals and trace elements were mainly in response to colostrum formation, changes in dry matter intake, and ruminal metabolism around calving. Decreased levels of vitamins A and E, and of Zn at calving might have negative implications for the functions of the immune defence. The lower proportion of CD62L+ neutrophils at calving may result in less migration of blood neutrophils into the tissues, and might contribute to the increased susceptibility to infections at this time.
Effects of feeding intensity during the dry period on leukocyte and lymphocyte sub-populations, neutrophil function and health in periparturient dairy cows
The Veterinary Journal, 2005
ABSTRACT The objective of this investigation was to study (1) the numbers of leukocytes, (2) the ... more ABSTRACT The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportions of lymphocytes expressing CD4, CD8, WC1, B or IL2R and (3) neutrophil phagocytosis and oxidative burst activity in blood around parturition in three groups of dairy cows fed different levels of a total mixed ration during the last eight weeks before calving. All cows were fed ad libitum during the first eight weeks of lactation. Serum concentration of the acute phase protein serum amyloid A (SAA), the milk somatic cell count (SCC) and disease incidence were also recorded. Special emphasis was given to the weeks just before and just after calving as dairy cows are known to be immune suppressed during this period. Dry period diet had only minor effects on leukocyte numbers, and did not influence neutrophil phagocytosis and oxidative burst. In addition, no effect was observed on disease incidence or SAA concentrations. However, an increase in the proportion of B-lymphocytes and a decrease in the proportion of WC1+ T lymphocytes were observed after calving in cows fed high or low energy rations during the dry period, but not in cows fed a medium energy ration. The weeks just before and after parturition were characterised by neutrophilia, eosinopenia, lymphopenia and monocytosis, but time had no effect on neutrophil phagocytosis and oxidative burst. The proportions of CD4+, CD8+, B+ and IL-2R+ lymphocytes increased in early lactation relative to the mid dry period. In addition, the concentration of SAA increased dramatically at calving. The results emphasise the need for more studies to clarify the complex interactions between nutrition and immunity during the peripartum period in dairy cattle.
α-Tocopherol concentration and stereoisomer composition in plasma and milk from dairy cows fed natural or synthetic vitamin E around calving
Journal of Dairy Research, 2006
The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of ... more The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of all-rac-α-tocopheryl acetate (SynAc), RRR-α-tocopheryl acetate (NatAc), or RRR-α-tocopherol (NatAlc), from approximately 3 weeks before estimated calving until 2 weeks after calving, on the concentration of α-tocopherol and its stereoisomers (RRR-, RSS-, RRS-, RSR- and the four 2S-forms of α-tocopherol) in blood and milk. An unsupplemented group was included as control. Blood samples were collected at 3, 2 and 1 weeks before estimated calving, at calving, and 3, 7 and 14 days after calving, while milk samples were taken twice within 24 h after calving and at 7 and 14 days in milk. Overall, time and treatment had significant effects on plasma α-tocopherol with higher concentrations in NatAc than in the other groups. In addition, SynAc had higher concentrations than Control, and NatAlc tended to be higher than Control. The lowest plasma concentrations were observed at calving and 3 days af...
Pérdidas de bonificaciones por calidad higiénica-sanitaria de leche entregada en tambos de la provincia de La Pampa
Las disminuciones de las bonificaciones, debido a la cantidad y calidad de leche remitida, dismin... more Las disminuciones de las bonificaciones, debido a la cantidad y calidad de leche remitida, disminuyen en forma significativa los ingresos por venta de leche en un numero importante de productores. Por consiguiente el objetivo principal de este proyecto fue evaluar las perdidas economicas en el precio final de la leche, por disminucion de bonificaciones en la calidad composicional, higienica, sanitaria y volumen de leche entregada en tambos de la provincia de La Pampa. Para la realizacion del trabajo se utilizaron registros de volumen y analisis de composicion y calidad higienico-sanitaria de leche de tanque de 59 tambos ubicados en la cuenca lechera pampeana (Mapa 1). Se obtuvieron promedios mensuales de kilogramos de proteina, que multiplicado por el valor unitario actual de la proteina determino el valor basico sin bonificaciones. A este valor se le aplicaron bonificaciones medias para unidades formadoras de colonias (UFC), conteo de celulas somaticas (CCS), temperatura y crioscop...
La respuesta inmunitaria contra los agentes infecciosos involucra una compleja interaccion entre ... more La respuesta inmunitaria contra los agentes infecciosos involucra una compleja interaccion entre diferentes tipos de celulas y sus productos, que culmina con la eliminacion del agente infeccioso o la muerte del animal. En el caso especifico de los bovinos lecheros, la mastitis sigue siendo una enfermedad con elevada incidencia y que ocasiona un elevado costo a la produccion lechera. Hay momentos, durante el ciclo productivo del animal, donde la susceptibilidad a dicha enfermedad es mayor. Por lo tanto, los objetivos de la presente revision son hacer una breve descripcion de los mecanismos inmunitarios y no inmunitarios implicados en la defensa de la glandula mamaria de los bovinos y remarcar la existencia de los periodos clave de elevada susceptibilidad a la mastitis
Evaluación de la efectividad de una vacuna contra Mastitis por staphylococus aureus streptococus agalactiae en vacas lecheras
La mastitis es una afeccion de la glandula mamaria que reduce la produccion de leche y perjudica ... more La mastitis es una afeccion de la glandula mamaria que reduce la produccion de leche y perjudica notoriamente la calidad composicional y sanitaria de la misma. Las mastitis infecciosas, las mas frecuentemente encontradas en tambos comerciales, son producidas, en un 90 % de los casos, por bacterias de los generos Staphylococcus y Streptococcus. El objetivo de este trabajo fue comprobar el efecto de la utilizacion de una vacuna a base de Staphylococcus aureus y Streptococcus agalactiae sobre la incidencia de la mastitis producida por estos agentes en vacas lecheras y su produccion de leche durante los primeros 4 meses de lactancia. Se trabajo en un tambo de la zona este de La Pampa, con un lote de 62 vaquillonas, de paricion de otono. Las mismas se asignaron aleatoriamente a uno de dos tratamientos: T1 (Control) y T2 (Tratamiento). A lo largo del ensayo se descartaron 6 animales, por causas ajenas al ensayo, de manera que los grupos quedaron conformados por 28 animales cada uno. A las...
Fixed-time artificial insemination in beef cattle using CIDR-B devices, progesterone and estradiol benzoate
Theriogenology, 1999
Effects of feeding intensity during the dry period on leukocyte and lymphocyte sub-populations, neutrophil function and health in periparturient dairy cows
Veterinary Journal, May 1, 2005
The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportio... more The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportions of lymphocytes expressing CD4, CD8, WC1, B or IL2R and (3) neutrophil phagocytosis and oxidative burst activity in blood around parturition in three groups of dairy cows fed different levels of a total mixed ration during the last eight weeks before calving. All cows
α-Tocopherol concentration and stereoisomer composition in plasma and milk from dairy cows fed natural or synthetic vitamin E around calving
Mastitis in dairy production, 2005
Immunized Goat with a Conjunctival Vaccine Prevent the Abortus Despite Revaccination with the Same Strain
International Journal of Infectious Diseases, 2022
Journal of Veterinary Medicine, Series B, 2008
Cows with subclinical mastitis caused by Staphylococcus aureus were subjected to subcutaneous inj... more Cows with subclinical mastitis caused by Staphylococcus aureus were subjected to subcutaneous injections with either an extract from the root of Panax ginseng CA Meyer at a dose of 8 mg/kg body weight per day for 6 days, or with saline as a control. The injection areas were checked for adverse reactions. The daily milk production was measured before and after treatment. Blood was collected for total and differential leucocyte counts, identi®cation of lymphocyte subpopulations using¯ow cytometry, lymphocyte proliferation test, and neutrophil phagocytosis and oxidative burst assay. Quarter milk samples were collected for bacteriological analysis and somatic cell counts (SCC). After the end of treatment, the numbers of S. aureus-infected quarters and milk SCC tended to decrease in ginseng-treated cows. Phagocytosis and oxidative burst activity of blood neutrophils were signi®cantly increased 1 week after ginseng treatment, but the proliferative response of blood lymphocytes did not change signi®cantly. The number of monocytes in ginseng-injected cows was signi®cantly higher 1 week post-treatment than pre-treatment, and the number of lymphocytes was signi®cantly higher than pre-infusion at 2 and 3 weeks after ginseng treatment. Similar changes were not observed in the control group. The present ®ndings indicate that ginseng treatment can activate the innate immunity of cows and may contribute to the cow's recovery from mastitis. It is therefore suggested that ginseng has a potential as a stimulator of the immune system of dairy cows.
Valoración de aspectos productivos (carne / lana) en biotipos ovinos característicos de la región norte de La Pampa
Caracterización de las explotaciones lecheras de La Pampa
Ab Intus, Jul 29, 2020
Glándula mamaria y lactación
Efecto de la vacunación conjuntival (REV-1) contra brucelosis en cabras pre-inmunizadas durante el máximo periodo de susceptibilidad a la enfermedad
Ciencia Veterinaria, 2017
Inactivated vaccines of national production, for use in the equine, carried mostly in its formula... more Inactivated vaccines of national production, for use in the equine, carried mostly in its formulation as an adjuvant, aluminum hydroxide Al(OH)3. Nowadays there are new adjuvants potentially superior to the traditional, either with respect to an increase in the time of permanence of the antigen in the host, and the immune response that induce. In the present work was compared the action of adjuvant Emulsigen respect aluminum hydroxide, which were used in a vaccine against equine influenza. For this purpose were established two test models, horses and guinea pigs, and the immune response induced was assessed by means of the determination of antibody titers. The results showed higher titers and extended serum antibodies persistence with the vaccine adjuvanted with Emulsigen, in relation to that adjuvanted with Al(OH)3, likewise were not observed adverse reaction in the site of inoculation.
Ciencia Veterinaria, 2017
La mastitis es una afección de la glándula mamaria que reduce la producción de leche y perjudica ... more La mastitis es una afección de la glándula mamaria que reduce la producción de leche y perjudica notoriamente la calidad composicional y sanitaria de la misma. Las mastitis infecciosas, las más frecuentemente encontradas en tambos comerciales, son producidas, en un 90 % de los casos, por bacterias de los géneros Staphylococcus y Streptococcus. El objetivo de este trabajo fue comprobar el efecto de la utilización de una vacuna a base de Staphylococcus aureus y Streptococcus agalactiae sobre la incidencia de la mastitis producida por estos agentes en vacas lecheras y su producción de leche durante los primeros 4 meses de lactancia. Se trabajó en un tambo de la zona este de La Pampa, con un lote de 62 vaquillonas, de parición de otoño. Las mismas se asignaron aleatoriamente a uno de dos tratamientos: T1 (Control) y T2 (Tratamiento). A lo largo del ensayo se descartaron 6 animales, por causas ajenas al ensayo, de manera que los grupos quedaron conformados por 28 animales cada uno. A las...
Ciencia Veterinaria, 2017
El objetivo de este trabajo fue determinar la evolución de la calidad del agua en establecimiento... more El objetivo de este trabajo fue determinar la evolución de la calidad del agua en establecimientos de la cuenca lechera de La Pampa. Se planteó la hipótesis de que los megatambos, debido a su alto número de animales (400 a 700 vacas), podrían causar una salinización del agua de bebida, por un uso excesivo de las napas, y la contaminación de las mismas, por la gran acumulación de efluentes. Se decidió compararlos con tambos medianos (lOO a 250 vacas) para evaluar el impacto de ambos modelos sobre la calidad del agua. Se trabajó con un total de 8 tambos en cada categoría. Las muestras de agua se obtuvieron semestralmente, durante 3 años consecutivos, y sobre ellas se realizaron análisis químicos (pR, Sales Totales, Dureza, Sulfatos, Cloruros, Nitratos, Nitritos, Amoníaco, Calcio, Magnesio, Flúor y Arsénico) y bacteriológicos. No pudo demostrarse, en ninguno de los dos grupos, un incremento estadísticamente significativo de la salinidad total del agua durante el período de estudio, aún...
Innocuousness and immune response of young bulls vaccinated with S19 either subcutaneously or conjunctival
Blood samples from ten Swedish dairy cows were taken one month before calving, at calving, and on... more Blood samples from ten Swedish dairy cows were taken one month before calving, at calving, and one month after calving. The blood concentration of vitamins A and E, and the trace element selenium (Se) were analysed, as well as the total and differential white blood cell counts,a nd the presenceo f CD62L and CD18 adhesionm oleculeso n blood neutrophils. The levels of vitamins A and E decreased significantly at calving, while whole blood Se increased Leukocytosisw as detectedat calving, explainedm ainly by neutrophilia.T he number of lymphocytest endedt o decreasea t calvrng.T he proportion of CD62L- neutrophilsd ecreased sisnlficantlv at this ttme
Waller K: Changes in some blood micronutrients, leukocytes and neutrophil expression of adhesion ... more Waller K: Changes in some blood micronutrients, leukocytes and neutrophil expression of adhesion molecules in periparturient dairy cows. Acta vet. scand. 2001, 42, 139-150.-Dairy cows are highly susceptible to infectious diseases, like mastitis, during the period around calving. Although factors contributing to increased susceptibility to infection have not been fully elucidated, impaired neutrophil recruitment to the site of infection and changes in the concentrations of some micronutrients related with the function of the immune defence has been implicated. Most of the current information is based on studies outside the Nordic countries where the conditions for dairy cows are different. Therefore, the aim of the study was to evaluate changes in blood concentrations of the vitamins A and E, the minerals calcium (Ca), phosphorous (P), and magnesium (Mg), the electrolytes potassium (K) and sodium (Na) and the trace elements selenium (Se), copper (Cu) and zinc (Zn), as well as changes in total and differential white blood cell counts (WBC) and expression of the adhesion molecules CD62L and CD18 on blood neutrophils in Swedish dairy cows during the period around calving. Blood samples were taken from 10 cows one month before expected calving, at calving and one month after calving. The results were mainly in line with reports from other countries. The concentrations of vitamins A and E, and of Zn, Ca and P decreased significantly at calving, while Se, Cu, and Na increased. Leukocytosis was detected at calving, mainly explained by neutrophilia, but also by monocytosis. The numbers of lymphocytes tended to decrease at the same time. The mean fluorescent intensity (MFI) of CD62L and CD18 molecules on blood neutrophils remained constant over time. The proportion of CD62L + neutrophils decreased significantly at calving. The animals were fed according to, or above, their requirements. Therefore, changes in blood levels of vitamins, minerals and trace elements were mainly in response to colostrum formation, changes in dry matter intake, and ruminal metabolism around calving. Decreased levels of vitamins A and E, and of Zn at calving might have negative implications for the functions of the immune defence. The lower proportion of CD62L+ neutrophils at calving may result in less migration of blood neutrophils into the tissues, and might contribute to the increased susceptibility to infections at this time.
Effects of feeding intensity during the dry period on leukocyte and lymphocyte sub-populations, neutrophil function and health in periparturient dairy cows
The Veterinary Journal, 2005
ABSTRACT The objective of this investigation was to study (1) the numbers of leukocytes, (2) the ... more ABSTRACT The objective of this investigation was to study (1) the numbers of leukocytes, (2) the proportions of lymphocytes expressing CD4, CD8, WC1, B or IL2R and (3) neutrophil phagocytosis and oxidative burst activity in blood around parturition in three groups of dairy cows fed different levels of a total mixed ration during the last eight weeks before calving. All cows were fed ad libitum during the first eight weeks of lactation. Serum concentration of the acute phase protein serum amyloid A (SAA), the milk somatic cell count (SCC) and disease incidence were also recorded. Special emphasis was given to the weeks just before and just after calving as dairy cows are known to be immune suppressed during this period. Dry period diet had only minor effects on leukocyte numbers, and did not influence neutrophil phagocytosis and oxidative burst. In addition, no effect was observed on disease incidence or SAA concentrations. However, an increase in the proportion of B-lymphocytes and a decrease in the proportion of WC1+ T lymphocytes were observed after calving in cows fed high or low energy rations during the dry period, but not in cows fed a medium energy ration. The weeks just before and after parturition were characterised by neutrophilia, eosinopenia, lymphopenia and monocytosis, but time had no effect on neutrophil phagocytosis and oxidative burst. The proportions of CD4+, CD8+, B+ and IL-2R+ lymphocytes increased in early lactation relative to the mid dry period. In addition, the concentration of SAA increased dramatically at calving. The results emphasise the need for more studies to clarify the complex interactions between nutrition and immunity during the peripartum period in dairy cattle.
α-Tocopherol concentration and stereoisomer composition in plasma and milk from dairy cows fed natural or synthetic vitamin E around calving
Journal of Dairy Research, 2006
The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of ... more The aim of this study was to compare the effects of supplementing dairy cows with 1000 IU/day of all-rac-α-tocopheryl acetate (SynAc), RRR-α-tocopheryl acetate (NatAc), or RRR-α-tocopherol (NatAlc), from approximately 3 weeks before estimated calving until 2 weeks after calving, on the concentration of α-tocopherol and its stereoisomers (RRR-, RSS-, RRS-, RSR- and the four 2S-forms of α-tocopherol) in blood and milk. An unsupplemented group was included as control. Blood samples were collected at 3, 2 and 1 weeks before estimated calving, at calving, and 3, 7 and 14 days after calving, while milk samples were taken twice within 24 h after calving and at 7 and 14 days in milk. Overall, time and treatment had significant effects on plasma α-tocopherol with higher concentrations in NatAc than in the other groups. In addition, SynAc had higher concentrations than Control, and NatAlc tended to be higher than Control. The lowest plasma concentrations were observed at calving and 3 days af...
Pérdidas de bonificaciones por calidad higiénica-sanitaria de leche entregada en tambos de la provincia de La Pampa
Las disminuciones de las bonificaciones, debido a la cantidad y calidad de leche remitida, dismin... more Las disminuciones de las bonificaciones, debido a la cantidad y calidad de leche remitida, disminuyen en forma significativa los ingresos por venta de leche en un numero importante de productores. Por consiguiente el objetivo principal de este proyecto fue evaluar las perdidas economicas en el precio final de la leche, por disminucion de bonificaciones en la calidad composicional, higienica, sanitaria y volumen de leche entregada en tambos de la provincia de La Pampa. Para la realizacion del trabajo se utilizaron registros de volumen y analisis de composicion y calidad higienico-sanitaria de leche de tanque de 59 tambos ubicados en la cuenca lechera pampeana (Mapa 1). Se obtuvieron promedios mensuales de kilogramos de proteina, que multiplicado por el valor unitario actual de la proteina determino el valor basico sin bonificaciones. A este valor se le aplicaron bonificaciones medias para unidades formadoras de colonias (UFC), conteo de celulas somaticas (CCS), temperatura y crioscop...
La respuesta inmunitaria contra los agentes infecciosos involucra una compleja interaccion entre ... more La respuesta inmunitaria contra los agentes infecciosos involucra una compleja interaccion entre diferentes tipos de celulas y sus productos, que culmina con la eliminacion del agente infeccioso o la muerte del animal. En el caso especifico de los bovinos lecheros, la mastitis sigue siendo una enfermedad con elevada incidencia y que ocasiona un elevado costo a la produccion lechera. Hay momentos, durante el ciclo productivo del animal, donde la susceptibilidad a dicha enfermedad es mayor. Por lo tanto, los objetivos de la presente revision son hacer una breve descripcion de los mecanismos inmunitarios y no inmunitarios implicados en la defensa de la glandula mamaria de los bovinos y remarcar la existencia de los periodos clave de elevada susceptibilidad a la mastitis
Evaluación de la efectividad de una vacuna contra Mastitis por staphylococus aureus streptococus agalactiae en vacas lecheras
La mastitis es una afeccion de la glandula mamaria que reduce la produccion de leche y perjudica ... more La mastitis es una afeccion de la glandula mamaria que reduce la produccion de leche y perjudica notoriamente la calidad composicional y sanitaria de la misma. Las mastitis infecciosas, las mas frecuentemente encontradas en tambos comerciales, son producidas, en un 90 % de los casos, por bacterias de los generos Staphylococcus y Streptococcus. El objetivo de este trabajo fue comprobar el efecto de la utilizacion de una vacuna a base de Staphylococcus aureus y Streptococcus agalactiae sobre la incidencia de la mastitis producida por estos agentes en vacas lecheras y su produccion de leche durante los primeros 4 meses de lactancia. Se trabajo en un tambo de la zona este de La Pampa, con un lote de 62 vaquillonas, de paricion de otono. Las mismas se asignaron aleatoriamente a uno de dos tratamientos: T1 (Control) y T2 (Tratamiento). A lo largo del ensayo se descartaron 6 animales, por causas ajenas al ensayo, de manera que los grupos quedaron conformados por 28 animales cada uno. A las...