Evaluation of vaginoscopy for the diagnosis of clinical endometritis in dairy cows

The objective of the study was to evaluate the visual assessment of vaginal discharge by vaginoscopy for the diagnosis of clinical endometritis (CE) in dairy cows. In an in vivo trial, inter- and intraobserver repeatability of vaginoscopic examination (VE) was determined and the effect of transrectal palpation and experience of the investigator evaluated. Holstein-Friesian cows (n=380) were examined by vaginoscopy between 21 and 27 d in milk by 3 investigators twice. Vaginal discharge was categorized on a 4-point classification system (0=clear mucus, 1=mucus containing flecks of pus, 2=discharge containing less than 50% pus, 3=discharge containing more than 50% pus). Cows with a vaginal discharge score (VDS) of 0 were classified as healthy, whereas cows with a VDS of 1 to 3 were classified as having CE. Vaginal discharge score on a scale from 0 to 3 has moderate intra- (Cohen's kappa coefficient, κ=0.55-0.60) and interobserver (κ=0.44) repeatability. The prevalence of CE was comparable between the 3 investigators (first VE: 42.6, 34.8, and 38.7; second VE 46.8, 36.9, and 43.7%). Transrectal palpation (relative risk=0.96-1.03) or experience of the investigator (relative risk=0.9-1.1) did not affect results of VE. In an in vitro trial, sensitivity and specificity of visual assessment were determined utilizing 33 images showing yellow and pink areas in certain percentages as a reference standard. Pus was represented by yellow areas and the mucosa, including clear mucus, by pink areas. These images were visually assessed by 30 investigators via PowerPoint presentation (experiment 1) and by 23 investigators via a simulated vaginal examination (experiment 2) utilizing the same 4-point classification system. Sensitivity was 99.6 and 96.3% and specificity was 96.7 and 90.1% in experiments 1 and 2, respectively. The results provide evidence that a visual assessment conducted by vaginoscopic examination is not perfect but can be considered a reasonable measurement of vaginal discharge and is a practical tool to distinguish healthy from diseased cows

The relationship between endometrial cytology during estrous cycle and cutoff points for the diagnosis of subclinical endometritis in grazing dairy cows

The objectives of this study were to assess the effect of the stage of estrous cycle on the percentage of endometrial polymorphonuclear cells (PMN) obtained by cytobrush to determine cutoff values for the diagnosis of subclinical endometritis under pastoral conditions, to measure the prevalence of subclinical endometritis 21 to 62d in milk (DIM), and to evaluate the effect of subclinical endometritis on reproductive performance in grazing dairy cows. The first experiment was conducted on a commercial dairy farm in Buenos Aires province (Argentina), where 17 postpartum cyclic dairy cows without clinical endometritis were selected and synchronized by Ovsynch protocol. Endometrial cytology (cytobrush technique) and blood (tail vessels) samples were obtained on d0, 4, 11, and 18 of the estrous cycle (corresponding to estrus, metestrus, diestrus, and proestrus, respectively) and used for measuring percentage of PMN and P4 concentration, respectively. The percentage of PMN was determined 3times by blinded count by 2 operators. Data were analyzed with PROC MIXED, PROC GENMOD, and PROC FREQ from SAS 9.1. The percentage of PMN did not vary with the stage of the estrous cycle. In addition, PMN counts were below any of the reported thresholds in this study (4%) for most of the cows. Therefore, the risk for false positive test results as a consequence of physiological changes in the counts of PMN during estrous cycle is low. The second experiment was conducted on 4 commercial dairy farms in Buenos Aires province (Argentina), where lactating Holstein dairy cows (n = 418) 21 to 62 DIM without clinical endometritis were studied. Samples of endometrial cytology were collected with the cytobrush technique. Data were analyzed with receiver operator characteristic curves with Sigmaplot 10.0, and with PROC GLIMMIX, PROC PHREG, and PROC LIFETEST from SAS 9.1. Cutoff values for the diagnosis of subclinical endometritis in grazing dairy cows are 8% PMN for 21 to 33 DIM, 6% PMN for 34 to 47 DIM, 4% PMN for 48 to 62 DIM, and overall 5% PMN for 21 to 62 DIM; the prevalence of subclinical endometritis 21 to 62 DIM was 17%. Finally, subclinical endometritis diagnosed at 21 to 62 DIM decreases the hazard for pregnancy (hazard ratio = 0.668; 95% confidence interval = 0.492-0.909) and increases the calving to conception interval by d30 compared with normal cows (median 95% confidence interval = 133 vs. 93, respectively).Facultad de Ciencias Veterinaria

Determining thresholds for the diagnosis of subclinical endometritis in Argentina

La endometritis subclínica (ES) afecta negativamente a la reproducción de las vacas de tambo al aumentar el intervalo entre partos. Para su diagnóstico, se debe tomar una muestra citológica del útero y determinar el porcentaje de neutrófilos (PPMN) que se encuentra superficialmente en el endometrio. Distintos PPMN han sido utilizados como puntos de corte de diagnóstico en vacas estabuladas. No es posible extrapolar datos de explotaciones intensivas a las condiciones argentinas de producción, tampoco el uso de valores de corte arbitrarios, debido a que se pueden llegar a interpretar en forma errónea los resultados arribando a diagnósticos incorrectos. Por lo tanto, el objetivo de este trabajo fue determinar la prevalencia de la ES diagnosticada por la técnica de CB en Argentina y buscar los niveles de corte que se correspondan con una disminución de la eficiencia reproductiva. Se muestrearon y evaluaron 487 vacas con flujo vaginal normal entre 21 y 62 días postparto (dpp). Los datos fueron analizados por SAS y SigmaPlot. Las curvas ROC (acrónimo de Característica Operativa del Receptor) obtenidas arrojaron valores de corte de 8, 6, 4 y 5 PPMN para los intervalos 21-33, 34-47, 48-62 y 21-62 dpp respectivamente. Las vacas con ES tuvieron menor tasa de concepción al primer servicio (16,2%) y tuvieron 29 días más de abiertas comparados con vacas sin ES.Subclinical endometritis (SE) adversely affects the reproduction of dairy cows by increasing the number of days open. For diagnosis of subclinical endometritis, it is necessary to take a cytological sample of the uterus and determine the percent of neutrophils (PPMN) present at the endometrial surface. Different percentages have been used as diagnostic cutoffs in dairy cows. It is not possible to extrapolate data of intensive productions to Argentine pastoral conditions, or to use arbitrary cutoff values. This could result in erroneous interpretation of results and misdiagnosis of subclinical endometritis. The aim of this study was to validate cytobrush technique in our country and find cutoff values which correspond to a real decline in reproductive efficiency. For this work 487 cows with normal vaginal discharge between 21 and 62 days postpartum (dpp) were sampled and subclinical endometritis was diagnosed. Data were analyzed by SAS and Sigma Plot. ROC (Receiver Operating Characteristic) curves generated cutoff values of 8, 6, 4 and 5 PPMN for the intervals 21-33, 34-47, 48-62 and 21-62 dpp, respectively. Cows with subclinical endometritis had a 16.2% reduction in first conception rate and had 29 more open days than cows without subclinical endometritis.Fil: Madoz, Laura Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Teriogenología. Cátedra de Reproducción Animal; ArgentinaFil: Plöntzke, J.. Freie Universitat Berlin (freie Universitat Berlin); AlemaniaFil: Albarracín, D.. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Cátedra de Patología Especial; ArgentinaFil: Drillich, M.. Universidad de Medicina Veterinaria; AustriaFil: de la Sota, Rodolfo Luzbel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Veterinarias. Instituto de Teriogenología. Cátedra de Reproducción Animal; Argentin

The relationship between endometrial cytology during estrous cycle and cutoff points for the diagnosis of subclinical endometritis in grazing dairy cows

The objectives of this study were to assess the effect of the stage of estrous cycle on the percentage of endometrial polymorphonuclear cells (PMN) obtained by cytobrush to determine cutoff values for the diagnosis of subclinical endometritis under pastoral conditions, to measure the prevalence of subclinical endometritis 21 to 62d in milk (DIM), and to evaluate the effect of subclinical endometritis on reproductive performance in grazing dairy cows. The first experiment was conducted on a commercial dairy farm in Buenos Aires province (Argentina), where 17 postpartum cyclic dairy cows without clinical endometritis were selected and synchronized by Ovsynch protocol. Endometrial cytology (cytobrush technique) and blood (tail vessels) samples were obtained on d0, 4, 11, and 18 of the estrous cycle (corresponding to estrus, metestrus, diestrus, and proestrus, respectively) and used for measuring percentage of PMN and P4 concentration, respectively. The percentage of PMN was determined 3times by blinded count by 2 operators. Data were analyzed with PROC MIXED, PROC GENMOD, and PROC FREQ from SAS 9.1. The percentage of PMN did not vary with the stage of the estrous cycle. In addition, PMN counts were below any of the reported thresholds in this study (4%) for most of the cows. Therefore, the risk for false positive test results as a consequence of physiological changes in the counts of PMN during estrous cycle is low. The second experiment was conducted on 4 commercial dairy farms in Buenos Aires province (Argentina), where lactating Holstein dairy cows (n = 418) 21 to 62 DIM without clinical endometritis were studied. Samples of endometrial cytology were collected with the cytobrush technique. Data were analyzed with receiver operator characteristic curves with Sigmaplot 10.0, and with PROC GLIMMIX, PROC PHREG, and PROC LIFETEST from SAS 9.1. Cutoff values for the diagnosis of subclinical endometritis in grazing dairy cows are 8% PMN for 21 to 33 DIM, 6% PMN for 34 to 47 DIM, 4% PMN for 48 to 62 DIM, and overall 5% PMN for 21 to 62 DIM; the prevalence of subclinical endometritis 21 to 62 DIM was 17%. Finally, subclinical endometritis diagnosed at 21 to 62 DIM decreases the hazard for pregnancy (hazard ratio = 0.668; 95% confidence interval = 0.492-0.909) and increases the calving to conception interval by d30 compared with normal cows (median 95% confidence interval = 133 vs. 93, respectively).Facultad de Ciencias Veterinaria

A systems biology approach to bovine fertility and metabolism: Introduction of a glucose insulin model

To counteract the antagonistic relationship between milk yield and fertility in dairy cow, a deeper understanding of the underlying biological mechanisms is required. For this purpose, we study physiological networks related to reproduction and metabolism in dairy cows. We interactively develop dynamic, mechanistic models by fitting the models to experimental data and mechanistic knowledge. We have already developed models for potassium balance and hormonal regulation of fertility in the dairy cow, which will briefly be reviewed here. The main focus of this article is a glucose-insulin model currently developed by us. This model links the bovine hormonal cycle and the potassium balance to glucose and thus to energy metabolism. The models can be applied in scientific research, education, experimental planning, drug development and production on farms

Exploration of different wave patterns in a model of the bovine estrous cycle by Fourier analysis

Cows typically have different numbers of follicular waves during their hormonal cycle. Understanding the underlying regulations leads to insights into the reasons for declined fertility, a phenomenon that has been observed during the last decades. We present a systematic approach based on Fourier analysis to examine how parameter changes in a model of the bovine estrous cycle lead to different wave patterns. Even without any biological considerations, this allows to detect the responsible model parameters that control the type of periodicity of the solution, thus supporting experimental planning of animal scientists

Integrating nutritional and reproductive models to improve reproductive efficiency in dairy cattle

Successful reproduction requires coordination among neural, endocrine and nutritional systems leading to ovulation, insemination and a uterine environment that allows embryonic growth and attachment. These processes are a function of genetics, dietary nutrient composition and intake, and housing and climate. We lack a systems biology approach to study and define the control of reproduction in the dairy cow. Pregnancy rates in the best managed herds only approach 25 to 30%, and may be due to the multifactorial nature of reproductive processes (McNamara, 2010). Lower fertility increases the cost for insemination because of low reproduction performance and remains a primary reason for culling cows in the first three weeks of lactation (Chagas et al., 2007). Additional days the cow is not pregnant beyond the optimal time post-calving are costly to the dairy producer. Low fertility has often been blamed on high rates of milk production, but this is not the only factor affecting reproduction (Sangsritavong et al., 2002). There are three major systems of reproduction that can be affected by genetics, nutrition and management: the hypothalamic-pituitary axis controlling initialization of cycling, the follicular development in the ovary leading to ovulation; and the successful fertilization and growth of an embryo in the uterine environment. Thus, the goal is to improve reproduction efficiency while decreasing any environmental impacts. Better nutritional management, genetic selection for fertility, and more attention to success can improve reproductive efficiency. In order to do all this efficiently, biosystems models can be of great efficacy

The relationship between endometrial cytology during estrous cycle and cutoff points for the diagnosis of subclinical endometritis in grazing dairy cows

The objectives of this study were to assess the effect of the stage of estrous cycle on the percentage of endometrial polymorphonuclear cells (PMN) obtained by cytobrush to determine cutoff values for the diagnosis of subclinical endometritis under pastoral conditions, to measure the prevalence of subclinical endometritis 21 to 62 d in milk (DIM), and to evaluate the effect of subclinical endometritis on reproductive performance in grazing dairy cows. The first experiment was conducted on a commercial dairy farm in Buenos Aires province (Argentina), where 17 postpartum cyclic dairy cows without clinical endometritis were selected and synchronized by Ovsynch protocol. Endometrial cytology (cytobrush technique) and blood (tail vessels) samples were obtained on d 0, 4, 11, and 18 of the estrous cycle (corresponding to estrus, metestrus, diestrus, and proestrus, respectively) and used for measuring percentage of PMN and P4 concentration, respectively. The percentage of PMN was determined 3 times by blinded count by 2 operators. Data were analyzed with PROC MIXED, PROC GENMOD, and PROC FREQ from SAS 9.1. The percentage of PMN did not vary with the stage of the estrous cycle. In addition, PMN counts were below any of the reported thresholds in this study (4%) for most of the cows. Therefore, the risk for false positive test results as a consequence of physiological changes in the counts of PMN during estrous cycle is low. The second experiment was conducted on 4 commercial dairy farms in Buenos Aires province (Argentina), where lactating Holstein dairy cows (n = 418) 21 to 62 DIM without clinical endometritis were studied. Samples of endometrial cytology were collected with the cytobrush technique. Data were analyzed with receiver operator characteristic curves with Sigmaplot 10.0, and with PROC GLIMMIX, PROC PHREG, and PROC LIFETEST from SAS 9.1. Cutoff values for the diagnosis of subclinical endometritis in grazing dairy cows are 8% PMN for 21 to 33 DIM, 6% PMN for 34 to 47 DIM, 4% PMN for 48 to 62 DIM, and overall 5% PMN for 21 to 62 DIM; the prevalence of subclinical endometritis 21 to 62 DIM was 17%. Finally, subclinical endometritis diagnosed at 21 to 62 DIM decreases the hazard for pregnancy (hazard ratio = 0.668; 95% confidence interval = 0.492–0.909) and increases the calving to conception interval by d 30 compared with normal cows (median 95% confidence interval = 133 vs. 93, respectively).Fil: Madoz, Laura Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clínica. Cátedra de Reproducción Animal; ArgentinaFil: Giuliodori, Mauricio Javier. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Ciencias Básicas. Cátedra de Fisiología; ArgentinaFil: Jaureguiberry, María. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clínica. Cátedra de Reproducción Animal; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Plöntzke, J.. Private practice; AlemaniaFil: Drillich, M.. University of Veterinary Medicine; AustriaFil: de la Sota, Rodolfo Luzbel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de la Plata. Facultad de Ciencias Veterinarias. Departamento de Clínica. Cátedra de Reproducción Animal; Argentin