Factores de riesgo para la incidencia de mastitis clínica en ganado lechero de Costa Rica
Archivos
Fecha
2015-06-08
Autores
Vargas, Bernardo
Mora, María Gabriela
ROMERO-ZUÑIGA, JUAN JOSE
Camacho, Jorge
Título de la revista
ISSN de la revista
Título del volumen
Editor
Universidad Nacional, Costa Rica
Resumen
Se realizó un estudio observacional retrospectivo para evaluar posibles factores de riesgo,
relacionados con la vaca y su entorno, sobre la
ocurrencia de primeros eventos de mastitis clínica en ganado lechero de Costa Rica. Se contó
con información de 313 406 lactancias, 101 125
vacas y 288 hatos. La frecuencia relativa de
mastitis a nivel poblacional fue de 11,6%, con
variaciones desde 0,3% hasta 70,7% entre los
hatos. La tasa de incidencia poblacional fue de
4,65 casos por cada 10 000 días a riesgo en la
lactancia, con oscilaciones entre 0,092 y 5,7 para
los diferentes hatos. Mediante regresión logística se evaluaron posibles factores de riesgo que
afectan la incidencia de mastitis. Se exploraron 2
modelos mixtos lineales generalizados (GLMM),
sin (modelo base) y con (modelo alternativo)
efectos de lactancia previa. Los factores fijos con
efecto significativo fueron: zona agroecológica,
grupo racial, año, número y mes de parto, periodo de lactancia, duración y producción de leche
en lactancia previa e historial previo de mastitis.
Las categorías de mayor vs. menor propensión a
contraer mastitis fueron, respectivamente: zona
bosque seco tropical (OR Odds ratio:11,03) vs.
bosque húmedo tropical (OR:0,97), grupo racial
Jersey×Pardo Suizo (OR:1,67) vs. Pardo Suizo
(OR: 1), partos en años previos a 1995 (OR:2,19) vs. posteriores a 2010 (OR:1), número de parto
4 (OR:1,19) vs. primer parto (OR:0,54), mes de
parto Marzo (OR:1,25) vs. Octubre (OR:0,95),
periodo de lactancia 1-30 días (OR:104) vs. 391-
420 días (OR:0,94). En covariables, un incremento de 30 d en longitud de la lactancia anterior se
asoció con OR de 1,04 y un incremento de 1000
kg en producción en la lactancia previa se asoció
con un OR de 1,17. Estos hallazgos pueden ser
útiles para el desarrollo de protocolos preventivos
enfocados a reducir la incidencia de mastitis en
los grupos de mayor riesgo.
Risk factors for clinical mastitis in dairy cattle of Costa Rica. A retrospective observational study was conducted to evaluate risk factors related to the cow and its environment on the occurrence of early events of clinical mastitis in dairy cattle of Costa Rica. Data on 313 406 lactations from 101 125 cows and 288 herds was available. The relative frequency of mastitis at the population level was 11.6%, ranging from 0.3% to 70.7% between herds. The population incidence rate was 4.65 cases per 10 000 days at risk in lactation, ranging from 0.092 to 5.7 between herds. Logistic regression was used to evaluate potential risk factors affecting incidence of clinical mastitis. Two generalized linear mixed models (GLMM) were explored, without (base model) and with (alternative model) effects from previous lactation. The fixed factors with significant effect were: agroecological zone, racial group, year, number and month of calving, stage of lactation, duration and milk production in previous lactation, and history of mastitis in previous lactation. Categories with higher vs. lower propensity to mastitis were, respectively: tropical dry forest (OR Odds ratio: 11.03) vs. tropical rainforest (OR: 0.97), breed type Jersey×Brown Swiss (OR: 1.67) vs. Brown Swiss (OR: 1), birth-year before 1995 (OR:2.19) vs. after 2010 (OR: 1), fourth parity (OR:1.19) vs. first parity (OR: 0.54), month of calving March (OR: 1.25) vs. October (OR: 0.95), stage of lactation 1-30 days (OR:1.04) vs. 391-420 days (OR: 0.94). In covariates, an increase of 30 d in the previous lactation length was associated with an OR of 1.04 and an increase in production of 1000 kg in the previous lactation was associated with an OR of 1.17. These findings may be useful for the development of preventive protocols aimed at reducing the incidence of mastitis in groups with a higher risk.
Risk factors for clinical mastitis in dairy cattle of Costa Rica. A retrospective observational study was conducted to evaluate risk factors related to the cow and its environment on the occurrence of early events of clinical mastitis in dairy cattle of Costa Rica. Data on 313 406 lactations from 101 125 cows and 288 herds was available. The relative frequency of mastitis at the population level was 11.6%, ranging from 0.3% to 70.7% between herds. The population incidence rate was 4.65 cases per 10 000 days at risk in lactation, ranging from 0.092 to 5.7 between herds. Logistic regression was used to evaluate potential risk factors affecting incidence of clinical mastitis. Two generalized linear mixed models (GLMM) were explored, without (base model) and with (alternative model) effects from previous lactation. The fixed factors with significant effect were: agroecological zone, racial group, year, number and month of calving, stage of lactation, duration and milk production in previous lactation, and history of mastitis in previous lactation. Categories with higher vs. lower propensity to mastitis were, respectively: tropical dry forest (OR Odds ratio: 11.03) vs. tropical rainforest (OR: 0.97), breed type Jersey×Brown Swiss (OR: 1.67) vs. Brown Swiss (OR: 1), birth-year before 1995 (OR:2.19) vs. after 2010 (OR: 1), fourth parity (OR:1.19) vs. first parity (OR: 0.54), month of calving March (OR: 1.25) vs. October (OR: 0.95), stage of lactation 1-30 days (OR:1.04) vs. 391-420 days (OR: 0.94). In covariates, an increase of 30 d in the previous lactation length was associated with an OR of 1.04 and an increase in production of 1000 kg in the previous lactation was associated with an OR of 1.17. These findings may be useful for the development of preventive protocols aimed at reducing the incidence of mastitis in groups with a higher risk.
Descripción
Palabras clave
COSTA RICA, MASTITIS BOVINA, GANADO DE LECHE, BOVINE MASTITIS, BOVINE CATTLE, MEDICINA CLÍNICA VETERINARIA, CLINICAL VETERINARY MEDICINE