RESUMEN
Deaths attributed to Senecio jacobaea were investigated. The animal presented was a mature bull that was lethargic and dragging its feet. The bull was euthanized and 3 other cows died. Significantly, this disease has not been documented in Ontario before, and clinical signs of icterus or hepatoencephalopathy were not observed.
Asunto(s)
Enfermedades de los Bovinos/epidemiología , Brotes de Enfermedades/veterinaria , Intoxicación por Plantas/veterinaria , Senecio/envenenamiento , Animales , Bovinos , Enfermedades de los Bovinos/diagnóstico , Resultado Fatal , Femenino , Masculino , Ontario/epidemiología , Intoxicación por Plantas/diagnóstico , Intoxicación por Plantas/epidemiologíaRESUMEN
By combining information from 2 databases, we investigated the possibility of an association between the genotype of Staphylococcus aureus causing bovine intramammary infection and dry-period cure of subclinical infection. The 1st database contained bacteriologic and cow data from a field study evaluating the efficacy in such infections of a new intramammary dry-cow therapy (DCT) containing tilmicosin phosphate, in comparison with a commercially available DCT containing benzathine cloxacillin. Isolates of S. aureus from that study were frozen and later independently analyzed by pulsed-field gel electrophoresis (PFGE) and macrorestriction DNA fingerprinting. The molecular information, summarized and published elsewhere, constituted the 2nd database. Data from 121 subclinically infected quarters of 92 cows from 40 herds were studied by univariate and multivariable regression analysis. Infection by an isolate of PFGE lineage group D was more likely than infection by an isolate of group A or F to be cured (P < 0.05). Cows infected by lineage group D had a higher linear somatic cell count score (LS) from the last Dairy Herd Improvement test before the dry period than did cows infected by the other lineage groups (P = 0.04). Although the probability of cure was significantly lower for cows with an LS at or above the mean of 5.7 for the study population (P = 0.05), when such a cow was infected with lineage group D, cure was significantly more likely (P < 0.001) than when it was infected by another lineage group. Significantly more (P = 0.02) of the infections treated with tilmicosin (74%) than of those treated with benzathine cloxacillin (53%) were cured, and significantly more (P = 0.05) of the infections by group D (81%) than of those by group A (57%) or group F (54%) were cured. However, there was no difference in cure rate for any PFGE genotype when tilmicosin phosphate was administered; when benzathine cloxacillin was administered, 87% of lineage group D isolates were eliminated, as compared with 46% of group A and 33% of group F isolates (P < 0.05). This research demonstrates that certain genotypes of S. aureus may naturally elicit a greater inflammatory response, yet be more susceptible to elimination by antibiotics in the dry period, than other genotypes.
Asunto(s)
Antibacterianos/farmacología , Mastitis Bovina/microbiología , Infecciones Estafilocócicas/veterinaria , Staphylococcus aureus , Animales , Antibacterianos/uso terapéutico , Bovinos , Recuento de Células/veterinaria , Cloxacilina/análogos & derivados , Cloxacilina/farmacología , Cloxacilina/uso terapéutico , Dermatoglifia del ADN/veterinaria , Electroforesis en Gel de Campo Pulsado/métodos , Electroforesis en Gel de Campo Pulsado/veterinaria , Genotipo , Macrólidos/farmacología , Macrólidos/uso terapéutico , Masculino , Mastitis Bovina/tratamiento farmacológico , Pruebas de Sensibilidad Microbiana , Leche/citología , Leche/microbiología , Análisis de Regresión , Infecciones Estafilocócicas/tratamiento farmacológico , Infecciones Estafilocócicas/microbiología , Staphylococcus aureus/efectos de los fármacos , Staphylococcus aureus/genética , Staphylococcus aureus/patogenicidad , Resultado del Tratamiento , Tilosina/análogos & derivados , Tilosina/farmacología , Tilosina/uso terapéuticoRESUMEN
OBJECTIVE: To determine whether insertion of an internal teat sealer (ITS) at the end of lactation would prevent development of new intramammary infections (IMIs) during the nonlactating period. DESIGN: Controlled clinical trial. ANIMALS: 939 Holstein-Friesian dairy cows from 16 herds. PROCEDURES: Results of bacteriologic culture of milk samples collected 14 days prior to the end of lactation were used to assign cows to groups (group 1 = negative results for all quarters; group 2 = positive results for > or = 1 quarter). Quarters of cows in group 1 were treated with an ITS or a single intramammary dose of cloxacillin; quarters of cows in group 2 were treated with cloxacillin in conjunction with an ITS or with cloxacillin alone. Milk samples were collected at the end of lactation and within 8 days after calving. RESULTS: Regardless of whether the outcome of interest was new IMIs caused by any pathogens, major pathogens, environmental pathogens, or streptococci other than Streptococcus agalactiae, quarters in group 2 treated with both cloxacillin and an ITS were less likely to develop a new IMI than were quarters treated with cloxacillin alone. For cows in group 1, no significant difference in risk of new IMIs was found between treatments. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that for dairy cattle with an IMI late in the lactation period, intramammary administration of cloxacillin at the end of lactation followed by insertion of an ITS enhanced protection against development of new IMIs, compared with use of cloxacillin alone.
Asunto(s)
Antibacterianos/uso terapéutico , Cloxacilina/uso terapéutico , Industria Lechera/métodos , Glándulas Mamarias Animales , Mastitis Bovina/prevención & control , Animales , Bovinos , Terapia Combinada/veterinaria , Femenino , Lactancia , Glándulas Mamarias Animales/microbiología , Glándulas Mamarias Animales/patología , Mastitis Bovina/epidemiología , Leche/citología , Leche/microbiología , Factores de RiesgoRESUMEN
The purpose of this study was to 1) estimate the herd prevalence of contagious mastitis pathogens in bulk milk from Prince Edward Island (PEI) dairy farms, 2) determine the association between bulk milk culture results and mean bulk milk somatic cell count (BMSCC), and 3) investigate the agreement of repeated bulk milk cultures. Three consecutive bulk milk samples were obtained at weekly intervals from all 258 PEI dairy herds and were cultured using routine laboratory methods. Cumulative prevalence of Staphylococcus aureus, Streptococcus agalactiae, and Mycoplasma spp. (M. bovis and M. alkalescens) was 74%, 1.6%, and 1.9%, respectively. Bulk milk somatic cell count of Staph. aureus-positive herds was higher than that of negative herds. Agreement for Staph. aureus isolation between 3 consecutive tests was moderate (kappa = 0.46). Mycoplasma bovis and M. alkalescens in bulk milk are being reported for the 1st time in PEI ever and in Canada since 1972.
Asunto(s)
Industria Lechera/normas , Mastitis Bovina/epidemiología , Mastitis Bovina/microbiología , Leche/citología , Leche/microbiología , Animales , Bovinos , Recuento de Células/veterinaria , Femenino , Mastitis Bovina/diagnóstico , Infecciones por Mycoplasma/epidemiología , Infecciones por Mycoplasma/veterinaria , Prevalencia , Isla del Principe Eduardo/epidemiología , Sensibilidad y Especificidad , Infecciones Estafilocócicas/epidemiología , Infecciones Estafilocócicas/veterinaria , Infecciones Estreptocócicas/epidemiología , Infecciones Estreptocócicas/veterinariaRESUMEN
The dry period has great implications on overall health and productivity in the subsequent lactation. Many anatomic, physiologic, and immunolgic changes are occurring for both the cow and the mammary gland during this time. These changes need to be understood and taken into consideration when assessing and implementing health management programs that involve this crucial time period. Specifically, nutritional and immunologic requirements of the individual cow need to be considered. The occurrence of many peripartum diseases is significantly influenced through nutritional and metabolic parameters that can be strongly influenced, controlled, and monitored in the dry period. From an udder-health perspective, the goal of the dry period can be met by recommending administration of DCT to all quarters of all cows at the end of lactation. As research continues to explore and define shortcomings of this approach and as scrutiny of the prophylactic use of antibiotics increases, however, novel approaches to preventing and eliminating IMI may become more readily available. These approaches offer new methods to improve upon and redefine what should be realistic goals of the dry period and afford an opportunity for continued improvement of udder health in today's dairy herds.
Asunto(s)
Antibacterianos/uso terapéutico , Mastitis Bovina/prevención & control , Animales , Antibacterianos/administración & dosificación , Bovinos , Femenino , Lactancia , Glándulas Mamarias Animales/microbiología , Mastitis Bovina/epidemiología , Paridad , Periodo Posparto , Embarazo , Factores de RiesgoRESUMEN
The purpose of this study was to evaluate the usefulness of the California mastitis test (CMT) to detect an intramammary infection caused by a major mastitis pathogen in early lactation cows. The gold standard used for comparison was bacteriological culture of single milk samples. The sensitivity (82.4%) and specificity (80.6%) of a positive CMT were highest on the 4th day of lactation.