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1.
J Dairy Sci ; 84(5): 1128-39, 2001 May.
Artículo en Inglés | MEDLINE | ID: mdl-11384039

RESUMEN

The objectives of this study were to describe the relationships between milk urea concentrations and nutritional management, production, and economic variables in commercial dairy herds. Dairy Herd Improvement (DHI) test-day milk urea data, production data, and information on ration nutrient composition and feeding management programs were collected over a 13-mo period from 53 commercial Ontario dairy herds. Economic variables included gross milk revenue, feed costs, and income over feed costs. Herd mean milk urea concentrations had a positive relationship with dietary levels of crude protein (CP), rumen degradable protein (RDP), and rumen undegradable protein (RUP) and a negative relationship with dietary levels of nonfiber carbohydrates (NFC), forage:concentrate (F:C) ratio, NFC:CP ratio, and NFC:RDP ratio. These findings are consistent with experimental studies that used chemical methods of milk urea analysis. Herd mean milk urea concentration was not associated with feeding management (e.g., total mixed rations, component feeding, feeding frequency, or synchrony of forage and concentrate feeding). Herd mean milk urea was not associated with either mean milk yield or linear score. Herd mean milk urea had a positive relationship with feed costs per cow per day but was not associated with gross milk revenue per cow per day. Herds with a high mean milk urea concentration tended to have lower income over feed costs per cow per day. High herd mean milk urea concentrations were associated with higher feed costs per kilogram of milk fat but lower gross milk revenue and lower income over feed costs per kilogram of milk fat. The results of this study demonstrate that DHI milk urea measurements produced by an infrared test method offer a useful tool for monitoring the efficiency of nitrogen utilization in commercial dairy herds. The results also suggest that diets may be balanced to achieve greater efficiency of nitrogen utilization, lower milk urea concentrations, and lower feed costs, while still achieving high milk production. This may lead to improved income over feed costs.


Asunto(s)
Industria Lechera/métodos , Leche/química , Urea/análisis , Alimentación Animal/análisis , Alimentación Animal/economía , Crianza de Animales Domésticos , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Bovinos , Análisis Costo-Beneficio , Industria Lechera/economía , Fibras de la Dieta/metabolismo , Proteínas en la Dieta/metabolismo , Femenino , Lactancia , Lípidos/análisis , Proteínas de la Leche/análisis , Ontario
2.
J Dairy Sci ; 84(6): 1397-406, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11417698

RESUMEN

Dairy herd improvement test-day data, including milk urea concentrations measured using infrared test method, were collected from 60 commercial Ontario Holstein dairy herds for a 13-mo period between December 1, 1995, and December 31, 1996. The objective of the study was to describe, at the cow and the group level, the relationship between DHI milk urea concentrations and reproductive performance in commercial dairy herds. When interpreted at the cow level, there was no association between milk urea and the risk for pregnancy from an insemination occurring within the 45-d period preceding test day. However, a negative curvilinear relationship existed between milk urea and the risk for pregnancy from a first, second, or third insemination event occurring within the 45-d period following test day, with the odds for pregnancy being highest when the milk urea on the test day preceding the insemination was either below 4.5 mmol/L or greater than 6.49 mmol/L, compared with a concentration between 4.5 and 6.49 mmol/L. When interpreted at the group level, there was no association between group mean milk urea for cows between 50 and 180 DIM, and the group conception rate for cows receiving a first, second, or third insemination event in the 45-d period either preceding or following test day. Thus, while DHI milk urea measurements may be useful as a management tool to improve the efficiency of production or reduce nitrogen excretion, through helping to optimize the efficiency of protein utilization, they may have limited utility as a monitoring or diagnostic tool for reproductive performance. The results of this study suggest that good fertility may be achieved across a broad range of milk urea concentrations.


Asunto(s)
Bovinos/fisiología , Lactancia/fisiología , Leche/química , Reproducción/fisiología , Urea/análisis , Animales , Bovinos/metabolismo , Femenino , Inseminación Artificial/veterinaria , Ontario , Embarazo , Espectrofotometría Infrarroja , Factores de Tiempo
3.
J Dairy Sci ; 84(1): 107-14, 2001 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11210021

RESUMEN

All DHI test-day data, including milk urea concentrations measured by infrared test method, were collected from 60 commercial Ontario Holstein dairy herds for a 13-mo period between December 1, 1995, and December 31, 1996. The objectives of this study were to describe the relationships between milk urea concentrations and seasonal factors, sampling factors, cow factors, and test-day production of milk, milk fat, protein, and SCC. Milk urea was associated with month and season; concentrations were the highest from July to September. Milk urea was generally lower in first-lactation cows. Milk urea was lowest during the first 60 d of lactation, higher between 60 and 150 d in milk, and lower after approximately 150 d in milk. In herds on an alternating a.m./p.m. test schedule, milk urea was generally lower in a.m. than p.m. tests. There was a positive nonlinear association between milk urea and milk yield, fat-corrected milk, and energy-corrected milk. There was a negative nonlinear association between milk urea and both milk fat and total protein percentages. While there was a negative nonlinear association between cow-level milk urea and linear score, the study found no association between herd average milk urea and herd average linear score. The associations described in this study using Dairy Herd Improvement test-day samples from commercial dairy herds and using an infrared test to measure milk urea are generally consistent with results from studies that used individual animals housed under research conditions and chemical methods to measure milk urea. Because milk urea varies by season, month, parity group, stage of lactation, and sample type, studies should control for these variables. Because of the apparent effect of a.m. and p.m. sampling on urea concentration, producers on an alternating a.m./p.m. test schedule should test routinely to establish a herd pattern for urea and submit the same sampling time consistently or both.


Asunto(s)
Leche/química , Urea/análisis , Factores de Edad , Animales , Bovinos , Recuento de Células , Ritmo Circadiano , Femenino , Lactancia/fisiología , Modelos Lineales , Ontario , Paridad , Estaciones del Año , Espectrofotometría Infrarroja , Factores de Tiempo
4.
J Dairy Sci ; 83(3): 435-42, 2000 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10750099

RESUMEN

The objective of this study was to determine if milk samples, as they are routinely collected by Ontario Dairy Herd Improvement, would yield accurate milk urea results with an infrared assay. This investigation involved analytic validation of the infrared assay and assessment of the effect of DHI routine sample acquisition factors on milk urea results. Analytic validation of an automated milk urea assay was performed by assessing the relative accuracy and precision of milk urea results produced by the Fossomatic 4000 Milk Analyzer, an infrared method of analysis, compared with the Eurochem test, an accepted reference method. Results indicated that, when interpreted at the group level, milk urea results between the infrared method and the reference test were in good agreement. The two tests shared a similar and high level of precision. Milk urea concentrations obtained from composite (metered) milk samples, and not quarter stripping samples, were most representative of concurrent serum urea concentrations. The addition of bronopol preservative did not result in a numerically important change in milk urea concentrations. Storage of preserved metered milk samples for up to 4 d at either room temperature or by refrigeration, or for up to 3 d by freezing, did not result in changes in milk urea concentrations. We concluded that milk samples, as they are routinely collected and handled by DHI, are suitable for measurement of milk urea concentrations with the infrared method of analysis if data are interpreted at the group level.


Asunto(s)
Autoanálisis/métodos , Leche/química , Urea/análisis , Animales , Industria Lechera/métodos , Conservantes de Alimentos , Congelación , Rayos Infrarrojos , Glicoles de Propileno , Sensibilidad y Especificidad , Manejo de Especímenes/métodos , Temperatura
5.
J Dairy Sci ; 82(11): 2377-84, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10575604

RESUMEN

Dry cows and pregnant heifers from 25 farms near Guelph, Ontario, Canada were enrolled in a large, double-blind, randomized clinical trial designed to evaluate the impact of monensin on energy metabolism, health, and production. A total of 503 cows was given monensin in controlled-release capsules, and 507 cows were administered placebo capsules 3 wk before expected calving date. The effects of treatment on health were evaluated using a logistic regression model. Treatment with monensin significantly reduced the incidence of abomasal displacement (OR = 0.41-0.84) and multiple illnesses (OR = 0.38-0.89). Monensin treatment tended to reduce the incidence of clinical ketosis (P = 0.11) and the risk of being culled (P = 0.09) in the first 94 d of lactation. Reproductive performance was analyzed with both a logistic regression model for conception rate and a survival analysis for days to first breeding and days from calving to conception. Treatment with monensin had no significant effect on any measure of reproductive performance.


Asunto(s)
Enfermedades de los Bovinos/prevención & control , Bovinos/fisiología , Monensina/administración & dosificación , Reproducción/efectos de los fármacos , Abomaso , Animales , Preparaciones de Acción Retardada , Método Doble Ciego , Metabolismo Energético/efectos de los fármacos , Femenino , Cetosis/prevención & control , Cetosis/veterinaria , Modelos Logísticos , Monensina/uso terapéutico , Embarazo , Gastropatías/prevención & control , Gastropatías/veterinaria
6.
J Dairy Sci ; 82(11): 2393-401, 1999 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-10575606

RESUMEN

The purpose of this study was to identify factors at the quarter and cow level that determine whether a quarter remains infected after an intramammary challenge with Staphylococcus aureus Newbould 305. A total of 135 cows were studied. Information on animal characteristics, cow-conformation, cow somatic cell count (SCC), and bacteriology, blood vitamin E levels, serology for retro-viral infections, bovine leukocyte adhesion deficiency-carrier status, and the presence of bovine lymphocyte antigens class I alleles was collected on each animal. All quarters of all cows were then challenged with Staphylococcus aureus Newbould 305. The challenge with S. aureus Newbould 305 resulted in 28 cows (20.7%) that did not establish infection in any of the quarters, 21 (15.6%) cows had 1 quarter infected, 35 (25.9%) had 2 quarters infected, 24 (17.8%) had 3 quarters infected, and 27 (20.0%) had all quarters infected. A higher prechallenge SCC decreased the risk of infection. An infection with Corynebacterium bovis prior to challenge decreased the risk of S.aureus infection. Of the bovine lymphocyte antigen alleles, the presence of the W20A allele proved to be significantly associated with a decreased risk of infection. No other factors proved to be significant.


Asunto(s)
Lactancia , Mastitis Bovina/inmunología , Infecciones Estafilocócicas/veterinaria , Alelos , Animales , Bovinos , Adhesión Celular , Recuento de Células , Susceptibilidad a Enfermedades/veterinaria , Femenino , Antígenos de Histocompatibilidad Clase I/genética , Leucocitos/fisiología , Leche/citología , Leche/microbiología , Embarazo , Factores de Riesgo , Infecciones Estafilocócicas/inmunología , Vitamina E/sangre
7.
J Am Vet Med Assoc ; 215(6): 798-804, 1999 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-10496131

RESUMEN

OBJECTIVE: To describe and evaluate hemostatic function in critically ill dogs with clinical signs of diseases that predispose to disseminated intravascular coagulation (DIC). DESIGN: Prospective case series. ANIMALS: 59 critically ill dogs (affected dogs) with clinical signs of diseases known to predispose to DIC and 52 clinically normal dogs (control dogs). PROCEDURE: Activated partial thromboplastin time (aPTT), prothrombin time (PT), thrombin clotting time (TCT), plasma fibrinogen concentration, serum concentration of fibrin and fibrinogen-related antigens (FRA), and plasma antithrombin III (AT III) activity were determined for all dogs. Results from affected dogs were compared with those of control dogs. In some affected dogs, postmortem tissue specimens were examined for evidence of microvascular thrombosis. A diagnosis of DIC was made by fulfilling at least 3 of the following criteria: 1) abnormal aPTT, PT, or TCT value, 2) low plasma fibrinogen concentration, 3) low plasma AT III activity, 4) high serum FRA concentration, or 5) low platelet count. To evaluate the severity of hemostatic dysfunction, 3 arbitrary categories (mild, moderate, and severe) were proposed. RESULTS: A diagnostic strategy based on moderate hemostatic dysfunction identified DIC in 16 of 59 (27.1%) affected dogs. The AT III activity was < 70% in 15 of 16 dogs with DIC. Microvascular thrombosis was observed in tissue specimens from 7 of 8 affected dogs. Serum FRA and plasma fibrinogen concentrations did not contribute in establishing a diagnosis of DIC. CONCLUSIONS AND CLINICAL RELEVANCE: A diagnosis of DIC can be made when hemostatic dysfunction is moderate in dogs with clinical signs of diseases associated with DIC.


Asunto(s)
Coagulación Intravascular Diseminada/veterinaria , Enfermedades de los Perros/diagnóstico , Animales , Antitrombina III/análisis , Estudios de Casos y Controles , Coagulación Intravascular Diseminada/sangre , Coagulación Intravascular Diseminada/diagnóstico , Enfermedades de los Perros/sangre , Perros , Femenino , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Fibrinógeno/análisis , Unidades de Cuidados Intensivos , Masculino , Tiempo de Tromboplastina Parcial/veterinaria , Estudios Prospectivos , Tiempo de Protrombina/veterinaria , Valores de Referencia , Tiempo de Trombina/veterinaria
8.
J Am Vet Med Assoc ; 215(6): 805-10, 1999 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-10496132

RESUMEN

OBJECTIVE: To evaluate the accuracy of point-of-care tests for the diagnosis of disseminated intravascular coagulation (DIC) in dogs and assess the correlation and agreement of results between point-of-care and laboratory tests in the evaluation of hemostatic function. DESIGN: Prospective case series. ANIMALS: 59 critically ill dogs (affected dogs) with clinical signs of diseases known to predispose to DIC and 52 clinically normal dogs. PROCEDURES: Accuracy of the point-of-care tests (activated clotting time [ACT], estimated platelet count and number of schizocytes from a blood smear, plasma total solids [TS] concentration, and the protamine sulfate test) was evaluated, using receiver operating characteristic curves and likelihood ratios. A strategy, using likelihood ratios to calculate a posttest probability of DIC, was tested with 65% used as a threshold for initiation of treatment. Results of laboratory tests (coagulogram and plasma antithrombin III activity) were used as the standard for comparison in each dog. RESULTS: ACT and estimated platelet count provided the best accuracy for detection of DIC. The plasma TS concentration, schizocyte number, and protamine sulfate test had poor accuracy. The strategy using post-test probability of DIC identified 12 of 16 affected dogs that had DIC. Estimated platelet count was correlated and had acceptable clinical agreement with automated platelet count (r = 0.70). The plasma TS (r = 0.28) concentration and serum albumin (r = 0.63) concentration were not accurate predictors of plasma antithrombin III activity. The ACT did not correlate with activated partial thromboplastin time (r = 0.28). CONCLUSIONS AND CLINICAL RELEVANCE: Strategic use of likelihood ratios from point-of-care tests can assist clinicians in making treatment decisions for dogs suspected to have DIC when immediate laboratory support is unavailable.


Asunto(s)
Coagulación Intravascular Diseminada/veterinaria , Enfermedades de los Perros/diagnóstico , Pruebas Hematológicas/veterinaria , Animales , Área Bajo la Curva , Estudios de Casos y Controles , Coagulación Intravascular Diseminada/sangre , Coagulación Intravascular Diseminada/diagnóstico , Enfermedades de los Perros/sangre , Perros , Recuento de Eritrocitos/veterinaria , Estudios de Evaluación como Asunto , Pruebas Hematológicas/normas , Antagonistas de Heparina , Unidades de Cuidados Intensivos , Funciones de Verosimilitud , Recuento de Plaquetas/veterinaria , Estudios Prospectivos , Protaminas , Curva ROC , Sensibilidad y Especificidad , Tiempo de Coagulación de la Sangre Total/veterinaria
9.
Can J Vet Res ; 63(3): 216-20, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10480465

RESUMEN

Freezing is a routine method of storage for plasma that is to be used in evaluating certain aspects of hemostatic function in many species. The purpose of this study was to evaluate the effect of storage at -70 degrees C for 6 mo on canine plasma samples. On fresh and frozen plasma from 12 clinically healthy dogs, prothrombin time, activated partial thromboplastin time, thrombin clotting time, fibrinogen determination, antithrombin III activity, fragment D and E assay, and protamine sulfate test were performed. Clinical agreement analysis was utilized to determine the effect of such storage on all assays. Individual differences detected between fresh and frozen samples were all within 2 standard deviations of the mean difference. With the exception of the activated partial thromboplastin time, storing canine plasma at -70 degrees C for 6 mo has no significant effect on hemostatic function, as assessed by these tests.


Asunto(s)
Criopreservación , Hemostasis , Manejo de Especímenes/veterinaria , Animales , Enfermedades de los Perros/diagnóstico , Perros , Pruebas Hematológicas/veterinaria
10.
J Dairy Sci ; 82(2): 272-9, 1999 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-10068948

RESUMEN

Dry cows and pregnant heifers from 25 farms near Guelph, Ontario, Canada were enrolled in a large double-blind, randomized clinical trial that was designed to evaluate the impact of monensin on energy metabolism, health, and production. A total of 503 cows was given monensin in controlled-release capsules, and 507 were administered placebo capsules 3 wk prior to the expected calving date. The effects of treatment on milk production and milk components at the first three Dairy Herd Improvement (DHI) tests were evaluated using repeated measures analysis of variance. Treatment with monensin increased milk production, but this effect was dependent on body condition score prior to calving. Cows that were classified as thin (score of < or = 3.0) did not have increased production in response to monensin treatment. Cows with fair body condition (score of 3.25 to 3.75) produced significantly more milk at the second DHI test (+0.85 kg), but cows that were fat (score of > or = 4.0) produced significantly more milk than did controls for all three DHI tests (+1.25 kg) in early lactation. Monensin significantly increased projected 305-d milk production in cows from herds at increased risk of ketosis. Treatment with monensin had no significant effect on either milk fat percentage or milk protein percentage.


Asunto(s)
Bovinos/fisiología , Lactancia/efectos de los fármacos , Leche/química , Monensina/farmacología , Animales , Composición Corporal , Preparaciones de Acción Retardada , Método Doble Ciego , Metabolismo Energético/efectos de los fármacos , Femenino , Estado de Salud , Lípidos/análisis , Proteínas de la Leche/análisis , Monensina/administración & dosificación , Placebos , Embarazo
11.
Equine Vet J Suppl ; (30): 438-42, 1999 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-10659296

RESUMEN

The plasma proteins are a significant contributor to the total weak acid concentration as a net anionic charge. Due to potential species difference, species-specific values must be confirmed for the weak acid anionic concentrations of proteins (Atot) and the effective dissociation constant for plasma weak acids (Ka). We studied the net anion load Atot of equine plasma protein in 10 clinically healthy mature Standardbred horses. A multi-step titration procedure, using a tonometer covering a titration range of PCO2 from 25 to 145 mmHg at 37 degrees C, was applied on the plasma of these 10 horses. Blood gases (pH, PCO2) and electrolytes required to calculate the strong ion difference ([SID] = [(Na(+) + K(+) + Ca(2+) + Mg(2+))-(Cl(-) + Lac(-) + PO4(2-))]) were simultaneously measured over a physiological pH range from 6.90-7.55. A nonlinear regression iteration to determine Atot and Ka was performed using polygonal regression curve fitting applied to the electrical neutrality equation of the physico-chemical system. The average anion-load Atot for plasma protein of 10 Standardbred horses was 14.89 +/- 0.8 mEq/l plasma and Ka was 2.11 +/- 0.50 x 10(-7) Eq/l (pKa = 6.67). The derived conversion factor (iterated Atot concentration/average plasma protein concentration) for calculation of Atot in plasma is 0.21 mEq/g protein (protein-unit: g/l). This value compares closely with the 0.24 mEq/g protein determined by titration of Van Slyke et al. (1928) and 0.22 mEq/g protein recently published by Constable (1997) for horse plasma. The Ka value compares closely with the value experimentally determined by Constable in 1997 (2.22 x 10(7) Eq/l). Linear regression of a set of experimental data from 5 Thoroughbred horses on a treadmill exercise test, showed excellent correlation with the regression lines not different from identity for the calculated and measured variables pH, HCO3 and SID. Knowledge of Atot and Ka for the horse is useful especially in exercise studies and in clinical conditions to quantify the mechanisms of the acid-base disturbances occurring.


Asunto(s)
Proteínas Sanguíneas/química , Caballos/sangre , Equilibrio Ácido-Base , Animales , Femenino , Concentración de Iones de Hidrógeno , Masculino , Condicionamiento Físico Animal , Deportes
12.
J Dairy Sci ; 81(11): 2866-73, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9839228

RESUMEN

A total of 1010 dry cows and pregnant heifers was randomly selected from 25 dairy farms near Guelph, Ontario, Canada to receive either a controlled-release capsule of monensin or a placebo at 3 wk prior to expected calving. Serum samples were obtained at the time of treatment administration, and both serum and milk samples were collected at wk 1, 2, 3, 6, and 9 postcalving. The threshold used to define subclinical ketosis was selected a priori at a concentration of > or = 1200 mumol/L of beta-hydroxybutyrate. Using this threshold, the prevalence and incidence of subclinical ketosis were significantly reduced (50%) by monensin treatment. The duration of subclinical ketosis for cows that had been treated with monensin was also shorter than that for cows treated with the placebo. Monensin treatment significantly reduced the incidence of subclinical ketosis when the threshold was defined using higher concentrations of serum beta-hydroxybutyrate (1400 and 2000 mumol/L). In addition, monensin significantly reduced the prevalence of positive milk ketone tests.


Asunto(s)
Enfermedades de los Bovinos/prevención & control , Cetosis/veterinaria , Monensina/uso terapéutico , Ácido 3-Hidroxibutírico/sangre , Animales , Bovinos , Femenino , Cetosis/sangre , Cetosis/prevención & control , Placebos , Embarazo , Estaciones del Año
13.
J Dairy Sci ; 81(9): 2354-61, 1998 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-9785226

RESUMEN

The effects of monensin on the energy metabolism of dairy cows in early lactation were investigated in a large clinical trial that was randomized and double-blinded. A total of 1010 Holstein cows and first lactation heifers were allocated to receive a controlled-release capsule of monensin or a placebo at 3 wk prior to expected calving date. Treatments were randomized across 25 dairy farms located near Guelph, Ontario, Canada. Serum samples obtained at the time of treatment administration and at wk 1, 2, 3, 6, and 9 postcalving were analyzed for beta-hydroxybutyrate, glucose, aspartate aminotransferase, urea, total protein, calcium, and phosphorus. Cows were also assigned a body condition score at the time each sample was obtained. Monensin treatment significantly reduced serum beta-hydroxy-butyrate concentrations at wk 1, 2, and 3 postpartum and significantly raised serum glucose concentrations during wk 1 and 2 of lactation. In addition, monensin treatment significantly reduced the loss of body condition score and decreased serum activity of aspartate aminotransferase during the postpartum period. Concentrations of serum urea were significantly higher during wk 2 and 3 postpartum for the cows that were treated with monensin. Monensin treatment had no effect on the concentrations of calcium, phosphorus, or total protein.


Asunto(s)
Bovinos/fisiología , Metabolismo Energético/efectos de los fármacos , Monensina/administración & dosificación , Ácido 3-Hidroxibutírico/sangre , Animales , Aspartato Aminotransferasas/sangre , Glucemia , Composición Corporal , Preparaciones de Acción Retardada , Método Doble Ciego , Femenino , Lactancia/fisiología , Monensina/uso terapéutico , Placebos , Periodo Posparto , Embarazo , Urea/sangre
14.
Can Vet J ; 38(11): 713-8, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9360791

RESUMEN

Serum beta-hydroxybutyrate (BHB) levels were determined for 1333 dairy cows in various stages of lactation and parity on 93 dairy farms in Ontario. The data were collected in a cross-sectional manner, as part of the 1992 Ontario Dairy Monitoring and Analysis Program. The median serum BHB was 536 mumol/L for all cows, with a range of 0 to 5801 mumol/L. When subclinical ketosis was defined as a serum BHB level of 1200 mumol/L or higher, the prevalence of ketosis for cows in early lactation (< 65 days in milk (DIM)) was 14.1%. Prevalences for mid lactation (65-149 DIM), late lactation (> 149 DIM), and dry cows were 5.3%, 3.2%, and 1.6%, respectively. The mean serum BHB was significantly higher in the early group compared with each of the other 3 groups (P < 0.05). There was a trend of increasing prevalence with increasing parity across all stages of lactation. Only the difference between the parity-1 group and the parity-4 and greater group was statistically significant (P < 0.05). Both test-day fat percent and test-day protein percent were significantly associated with subclinical ketosis. However, test-day fat percent and test-day protein percent, used alone or in combination, were not useful screening tests for identifying cows with subclinical ketosis.


Asunto(s)
Hidroxibutiratos/sangre , Cetosis/veterinaria , Ácido 3-Hidroxibutírico , Animales , Bovinos , Enfermedades de los Bovinos/sangre , Enfermedades de los Bovinos/diagnóstico , Enfermedades de los Bovinos/epidemiología , Estudios Transversales , Grasas de la Dieta/metabolismo , Femenino , Cetosis/sangre , Cetosis/diagnóstico , Cetosis/epidemiología , Lactancia , Proteínas de la Leche/metabolismo , Ontario/epidemiología , Paridad , Prevalencia
16.
J Am Vet Med Assoc ; 210(1): 65-71, 1997 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-8977651

RESUMEN

OBJECTIVE: To investigate causes of seizure disorders in cats. DESIGN: Case series. ANIMALS: 30 cats referred to the Ontario Veterinary College for recurrent seizures. PROCEDURES: Signalment and seizure pattern were evaluated. Diagnostic procedures included physical, neurologic, and fundic examinations; CBC; serum biochemical analyses, including determination of pre- and postprandial bile acid concentrations; urinalysis; serologic assays for FeLV and feline immunodeficiency virus, feline infectious peritonitis, and Toxoplasma gondii, magnetic resonance imaging of the brain; CSF analysis; and neuropathologic examination of euthanatized cats and of surgical biopsy specimens. RESULTS: All cats were found to have structural brain diseases; nonsuppurative meningoencephalitis of unknown cause was found in 14 cats, feline ischemic encephalopathy in 6, meningioma in 2, polycythemia vera with secondary brain lesions in 2, posttraumatic epilepsy in 1, and cerebral abscess in 1. A definitive diagnosis could not be reached in 4 cats. CLINICAL IMPLICATIONS: The most common cause of seizures in cats is structural brain disease. Structural brain lesions often can be detected on the basis of seizure pattern and results of neurologic examination. Cerebrospinal fluid analysis and brain imaging are essential to determine the cause of these lesions. Causes of seizures found in the cats of this study differ from those reported to be the most common. Nonsuppurative meningoencephalitis of unknown origin appears to be a frequent cause of neurologic disorders in cats, including seizure disorders. Feline ischemic encephalopathy appears to exist in a milder form than the classic disease and may be a common cause of seizures in cats.


Asunto(s)
Encefalopatías/veterinaria , Enfermedades de los Gatos/diagnóstico , Convulsiones/veterinaria , Animales , Ácidos y Sales Biliares/sangre , Recuento de Células Sanguíneas/veterinaria , Análisis Químico de la Sangre/veterinaria , Encéfalo/patología , Encefalopatías/complicaciones , Encefalopatías/diagnóstico , Isquemia Encefálica/complicaciones , Isquemia Encefálica/diagnóstico , Isquemia Encefálica/veterinaria , Enfermedades de los Gatos/etiología , Gatos , Líquido Cefalorraquídeo/química , Líquido Cefalorraquídeo/citología , Femenino , Imagen por Resonancia Magnética/veterinaria , Masculino , Meningoencefalitis/complicaciones , Meningoencefalitis/diagnóstico , Meningoencefalitis/veterinaria , Examen Neurológico/veterinaria , Recurrencia , Convulsiones/diagnóstico , Convulsiones/etiología , Urinálisis/veterinaria
17.
J Am Anim Hosp Assoc ; 31(4): 307-11, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7552662

RESUMEN

A retrospective study was undertaken to determine the prevalence of hypoalbuminemia in dogs with hypoadrenocorticism. During a 94-month interval, 17 of 44 dogs (38.6%) with hypoadrenocorticism were found to have hypoalbuminemia. When compared to all dogs with hypoalbuminemia (9.8%) observed in the hospital population during this same interval, there appeared to be a significant association between canine adrenocortical insufficiency and hypoalbuminemia. The pathogenesis of the hypoalbuminemia in this study is speculative; possible mechanisms include gastrointestinal blood loss, protein-losing enteropathy, malassimilation, or decreased albumin synthesis. Renal protein loss was not supported by routine urinalysis findings.


Asunto(s)
Insuficiencia Suprarrenal/veterinaria , Enfermedades de los Perros/etiología , Albúmina Sérica/deficiencia , Insuficiencia Suprarrenal/sangre , Insuficiencia Suprarrenal/etiología , Animales , Análisis Químico de la Sangre , Enfermedades de los Perros/sangre , Perros , Femenino , Masculino , Prevalencia , Estudios Retrospectivos
18.
Can Vet J ; 34(6): 360-4, 1993 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17424241

RESUMEN

A retrospective study was performed in order to assess the relationship between serum calcium and serum albumin concentrations in domestic animals. Results of 9041 canine, 1564 feline, 2917 equine, and 613 bovine serum samples from hospitalized patients were examined by regression analysis. Subpopulations of cases with concurrent elevations in creatinine or that were less than six months of age were evaluated separately. Statistically significant linear relationships between calcium and albumin concentrations were established for each species (p <0.05). The coefficients of determination (r(2)) were 0.169 for dogs, 0.294 for cats, 0.222 for horses, and 0.032 for cattle. The correlation coefficients (r) computed were: dogs = 0.411, cats = 0.543, horses = 0.471, cattle = 0.182. Neither increases in creatinine concentration nor juvenile age appreciably influenced the relationship between calcium and albumin concentrations. Interspecies variation was marked, and a strong correlation between calcium and albumin concentrations was not established in any species.

19.
Can J Vet Res ; 57(1): 9-13, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8431806

RESUMEN

Alterations of acid-base status, and fluid and electrolyte balance subsequent to exercise in Thoroughbred racehorses in North America have not been well-characterized. Des-cribed here are the results of an observational study conducted to characterize changes in fluid and electrolytes following strenuous exercise of 16 Thoroughbreds under routine training conditions. Changes following strenuous exercise were determined for the following variables: serum concentrations of sodium (Na), potassium (K), chloride (Cl) and protein; pH of blood; osmolality of plasma and urine; body weight; and, fractional urinary excretion (FE) of Na, K and Cl. The following changes occurred during exercise: increased concentration of Na in blood; increased FE of Na; decreased concentration of Cl in blood; decreased FE of Cl; increased urinary and plasmal osmolality; weight-loss; decreased pH of blood; and, increased concentration of lactic acid. The concurrent decreased concentration of chloride in plasma and acidemia in these horses differed from the hypochloremic, metabolic alkalosis previously described among endurance horses. Acidemia was attributed to production of lactic acid by anaerobic glycolysis.


Asunto(s)
Caballos/metabolismo , Condicionamiento Físico Animal , Esfuerzo Físico/fisiología , Equilibrio Hidroelectrolítico , Equilibrio Ácido-Base , Animales , Proteínas Sanguíneas/análisis , Electrólitos/sangre , Electrólitos/orina , Femenino , Hematócrito/veterinaria , Caballos/sangre , Caballos/orina , Concentración de Iones de Hidrógeno , Lactatos/sangre , Ácido Láctico , Masculino , Concentración Osmolar , Pérdida de Peso
20.
Am J Vet Res ; 54(1): 60-8, 1993 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-8427473

RESUMEN

Characteristic alterations in the serum and urine biochemical profiles of Doberman Pinschers with congestive heart failure (CHF) resulting from idiopathic dilated cardiomyopathy were determined. We compared these alterations with those observed in 2 other models of CHF: rate overload induced by rapid ventricular pacing in dogs, and biventricular hypertrophy and dilatation induced in turkey poults by furazolidone toxicosis. Serum and urine biochemical changes in both models of CHF in dogs were mild to moderate in degree, and were moderately consistent. They could be attributed to secondary neurohumoral, hepatic, and renal effects of heart failure. The most marked and consistent changes observed were mildly decreased anion gap that developed, in part, because of decreased serum sodium concentration, moderately increased catecholamine concentrations, moderate lactaciduria, hyposthenuria, and mildly increased urea concentrations and liver enzyme activities. In birds with furazolidone cardiomyopathy, we observed mild increases in serum urate concentration, liver and muscle enzyme activities, but moderately increased sodium concentration with decreased chloride concentration. In the pacing and furazolidone models, in which CHF was rapidly induced, moderate to marked hypoproteinemia was attributable to decreases in albumin and globulin concentrations. Using the avian model we found that the hypoproteinemia could be largely attributed to blood volume expansion, and to a lesser extent, inanition. Development of hypoalbuminemia during rapid ventricular pacing and furazolidone treatment may contribute to the effects of rate overload or drug toxicity in the pathogenesis of CHF, because hypoalbuminemia may contribute to altered hemodynamics and neuroendocrine system activation. Our data indicate that clinical biochemical analysis of serum and urine may be useful for assessing progression of CHF.


Asunto(s)
Enfermedades de los Perros/metabolismo , Furazolidona/toxicidad , Insuficiencia Cardíaca/veterinaria , Enfermedades de las Aves de Corral/metabolismo , Pavos/metabolismo , Animales , Estimulación Cardíaca Artificial/veterinaria , Enfermedades de los Perros/sangre , Enfermedades de los Perros/orina , Perros , Femenino , Insuficiencia Cardíaca/etiología , Insuficiencia Cardíaca/metabolismo , Masculino , Enfermedades de las Aves de Corral/inducido químicamente
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