RESUMO
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).
Assuntos
Doenças dos Bovinos/patologia , Endometrite/veterinária , Endométrio/patologia , Ciclo Estral/fisiologia , Neutrófilos/patologia , Animais , Argentina , Bovinos , Indústria de Laticínios , Endometrite/diagnóstico , Endometrite/patologia , Reações Falso-Positivas , Feminino , Fertilização/fisiologia , Herbivoria , Lactação , Contagem de Leucócitos , Período Pós-Parto , Gravidez , Progesterona/sangue , Reprodução/fisiologiaRESUMO
The objective of this study was to evaluate the prevalence of clinical endometritis and its impact on reproductive performance in grazing dairy cattle in Argentina to compare data with previous reports from herds kept in confinement housing systems. A total of 243 Holstein dairy cows from three commercial dairy farms in Buenos Aires Province (Argentina) were examined for the signs of clinical endometritis 18-38 days postpartum (dpp) by external inspection and manual vaginal examination. Vaginal discharge was scored into the categories VDS 0 (transparent, clear mucus), VDS 1 (mucupurulent discharge), VDS 2 (purulent discharge) and VDS 3 (purulent discharge with fetid odour). Cows diagnosed with VDS 1 to VDS 3 were regarded as affected with clinical endometritis and cows with VDS 0 as free of clinical endometritis. All cows were re-examined 14 days later following the same examination protocol. Prevalence of clinical endometritis 18-38 dpp was 35% and decreased to 18% at re-examination. Cows with no palpable ovarian structures or periparturient disorders were at higher risk for clinical endometritis. Hazard for pregnancy was significantly lower in cows with purulent or fetid odour discharge compared with reference cows with no discharge (HR=0.49; p=0.01), resulting in a lower proportion of cows pregnant by 360 dpp (66% vs 78%). Furthermore, the number of services per pregnancy was higher for cows with clinical endometritis than for cows without clinical endometritis (4.4 vs 3.1; p=0.04). Cows with clinical endometritis were 1.6 times as likely to be culled as cows with no signs of clinical endometritis. In conclusion, the prevalence and the impact of clinical endometritis in a pasture-based, extensive dairy production system in Argentina were similar to previously published data from dairy farms with confinement production systems.
Assuntos
Doenças dos Bovinos/epidemiologia , Endometrite/veterinária , Reprodução , Animais , Argentina/epidemiologia , Bovinos , Doenças dos Bovinos/diagnóstico , Indústria de Laticínios , Endometrite/diagnóstico , Endometrite/epidemiologia , Feminino , Gravidez , Descarga Vaginal/veterináriaRESUMO
Recently several studies have reported that subclinical endometritis impairs reproductive performance in cattle. Most of the studies were conducted in western industrialized countries under intensive housing conditions. The objective of the present study was to determine the prevalence of subclinical endometritis and its impact on reproductive performance outcomes in clinically healthy postpartum dairy cows in a pasture-based extensive dairy farming system in Argentina. Lactating Holstein cows (n=201) at 18-38 days postpartum (dpp) from three commercial dairy farms in Buenos Aires Province, Argentina, were examined for signs of clinical endometritis by external inspection and manual vaginal examination. Only cows without signs of clinical endometritis i.e. no vaginal discharge were enrolled in this study and examined for subclinical endometritis using the cytobrush technique. Cows with ≥5% polymorphonuclear cells (PMN) in the cytological sample were regarded as affected by subclinical endometritis. All cows were reexamined 14 days later following the same examination protocol. Prevalence of subclinical endometritis 18-38dpp was 38% and decreased to 19% at reexamination. The proportion of cows pregnant at first service was 29% and proportion of cows pregnant at 360pp was 73% and 75% in cows with subclinical endometritis and those without, respectively. The probability of conception at first service, hazards of insemination and pregnancy, respectively, were not affected by subclinical endometritis. Primiparous cows had a greater chance for insemination (HR=0.66; 95% CI=0.47-0.92) and pregnancy (HR=0.63; 95% CI=0.45-0.90) than multiparous cows. In conclusion subclinical endometritis did not affect reproductive performance outcomes in a pasture-based, extensive dairy farming system in Argentina.