Seropositivity for Bovine Viral Diarrhea and Enzootic Bovine Leukemia viruses in Blanco Orejinegro cattle in Colombia and infection associated-factors / Soropositividade para o vírus da diarréia viral bovina e leucemia bovina enzoótica em bovinos Blanco Orejinegro na Colômbia e fatores associados à infecção

ABSTRACT Serological controls for diseases of viral origin in animal production systems and the identification of factors associated with infections are decisive elements to establish prevention and control measures. The aim of this study was to establish the serological status for Bovine Viral Diarrhea (BVD) and Enzootic Bovine Leukemia (EBL) viruses in Blanco Orejinegro (BON) cattle from Colombia, and to identify the factors associated with seropositivity. A cross-sectional study was conducted with a total of 498 animals of all age groups and physiological states of the BON breed were selected, belonging to 14 herds located in 6 states of Colombia, in which a survey with 27 questions was conducted. By means of the chi-square test, possible factors associated with seropositivity against the 2 viruses were identified. A sample of 4 ml of blood was taken from each animal to extract plasma and make indirect Elisa tests to detect antibodies against both pathogens. General seropositivity of 27,1% was obtained for EBL, finding as factors associated with seropositivity the inadequate disposition of placental tissues after delivery of the cows and the non-performance of serological tests on new animals entering the herd. For BVD, seropositivity obtained was 50,6%, and the factors associated with seropositivity identified were having had a history of the disease in the herd, and using semen from bulls that are not known to be free for the infection. We suggest establishing control measures considering the factors associated with each viral infection to limit their expansion in the BON cattle production systems of Colombia.

RESUMO Os controles sorológicos para doenças de origem viral nos sistemas de produção animal e a identificação de fatores associados à infecção são elementos decisivos para estabelecer medidas de prevenção e controle. O objetivo deste estudo foi estabelecer o status sorológico dos vírus da Diarréia Viral Bovina (BVD) e da Leucemia Bovina Enzoótica (EBL) em bovinos Blanco Orejinegro (BON) da Colômbia e identificar os fatores associados à soropositividade. Foram selecionados 498 animais de todas as faixas etárias e estados fisiológicos da raça BON, de 14 rebanhos localizados em seis regiões da Colômbia, nos quais foi realizada uma pesquisa para identificar possíveis fatores associados à soropositividade contra os dois vírus. Foi retirada uma amostra de 4 ml de sangue de cada animal para extrair plasma e fazer testes ELISA indiretos para detectar anticorpos contra os dois patógenos. Obteve-se soropositividade geral de 27,1% para EBL, encontrando como fatores associados à soropositividade a disposição inadequada dos tecidos placentários após o parto das vacas e a não realização de testes sorológicos em novos animais que entraram no rebanho. Para a BVD, a soropositividade obtida foi de 50,6%, e os fatores associados à soropositividade identificados foram: histórico de doença no rebanho e uso de sêmen de touros que não são reconhecidos como livres da infecção. Sugerimos o estabelecimento de medidas de controle considerando os fatores associados a cada infecção viral para limitar sua expansão nos sistemas de produção de gado BON da Colômbia.

Enfermedad podal en bovinos: prevalencia y asociación con algunas variables / Podal disease in cows: prevalence and association with some variables

RESUMEN La enfermedad podal constituye uno de los síndromes más difíciles de controlar en la industria lechera. El presente estudio tuvo como objetivo cuantificar la prevalencia de enfermedad podal, evaluando su asociación con factores como raza, orden de parto y peso. Se trata de un estudio retrospectivo que utiliza los registros sanitarios y productivos de un hato lechero ubicado en el trópico alto de Colombia. Los componentes raciales presentes fueron Fl Holstein x Blanco Orejinegro, 3/4 Holstein 1/4 Blanco Orejinegro, 5/8 Holstein 3/8 Blanco Orejinegro y Holstein 100%. Se consideraron 6 órdenes de parto. La variable enfermedad podal presenta una distribución binomial. El efecto de los factores se verificó utilizando un modelo lineal generalizado, por medio de una regresión logística (PROC GENMOD SAS versión 9.4). En caso de existir diferencias significativas, se aplicó el procedimiento LSMEANS del SAS (versión 9.4) y un Odds Rattio entre los niveles que presentaron significancia. La prevalencia de enfermedad podal en el hato fue de 10,55%. Los factores de riesgo considerados fueron estadísticamente significativos: componente racial (p < 0,0009), orden parto (p < 0,0001) y peso medio de las vacas (p < 0,0001). Se observó un incremento en la prevalencia de la enfermedad asociado a la raza Holstein, orden de parto alto y bajo peso corporal. La prevalencia de enfermedad podal fue mayor en vacas Holstein puras y menor en vacas Holstein cruzadas con Blanco Orejinegro, debido a la resistencia por heterosis que la raza criolla aporta. El incremento del orden de parto al igual que el bajo peso se relacionan con una mayor prevalencia de esta enfermedad.

ABSTRACT Foot disease is one of the most difficult syndromes to control in the dairy industry. The goal of this study was to quantify the prevalence of foot disease, evaluating its association with factors such as race, calving order and weight. This is a retrospective study using the health and production records of a dairy herd located in the high tropics of Colombia. The racial components present were F1 Holstein x Blanco Orejinegro, 3/4 Holstein 1/4 Blanco Orejinegro, 5/8 Holstein 3/8 Blanco Orejinegro, Holstein 100%. 6 delivery orders were considered. The variable foot disease presents a binomial distribution. The effect of the factors was verified using a generalized linear model, by means of a logistic regression (PROC GENMOD SAS version 9.4). In the event of significant differences, the SAS LSMEANS procedure (version 9.4) and an Odds Ratio were applied between the levels that presented significance. The prevalence of foot disease in the herd was 10,55%. The risk factors considered were statistically significant: racial component (p < 0,0009), calving order (p < 0,0001) and average weight of the cows (p < 0,0001). An increase in the prevalence of the disease was observed associated with the Holstein breed, high calving order and low body weight. The prevalence of foot disease was higher in pure Holstein cows and lower in Holstein cows crossed with Blanco Orejinegro due to the resistance due to heterosis that the creole breed contributes. The increase in the delivery order as well as the low weight are related to a higher prevalence of this disease.