Risk factors associated with enzootic bovine leukosis in Boyacá and Cundinamarca municipalities, Colombia.

Background: Enzootic bovine leukosis (EBL) is a lymphoproliferative disorder caused by the bovine leukemia virus (BLV), a virus of the Retroviridae family. The infection is distributed worldwide, and a high percentage of animals infected by the BLV are asymptomatic and act as carriers of the virus in many cattle populations. Aim: To identify the risk factors associated with EBL in the municipalities of Boyacá and Cundinamarca (Colombia). Methods: A simple descriptive cross-sectional study with random sampling was conducted. A total of 1,140 blood samples were taken from cattle (females and males) from the municipalities of Chiquinquirá, Ubaté, and San Miguel de Sema of different breeds and age groups. The samples were processed using the commercial ELISA SERELISA® BLV Ab Mono Blocking kit (sensitivity 97%, specificity 98%). The data were processed with the statistical programs WinEpi and Epi Info® version 7.2.4.0, estimating the prevalence ratio, implementing the chi-square test (p ≤ 0.05) and logistic regression. Results: A true prevalence (TP) and apparent prevalence (AP) of 23.61% and 22.7% in Ubaté, 19.22% and 18.1% in Chiquinquirá, and 15.61% and 14.3% in San Miguel de Sema, respectively, were established. Bovines 2-4 years old were the most prevalent in Ubaté and Chiquinquirá (37.5% and 21.21%, respectively), while in San Miguel de Sema individuals >4 years had the highest percentage of antibodies (18.3%). The Holstein breed had a higher prevalence in Ubaté and San Miguel de Sema (26.02% and 19.67%), and crossbreeds were more BLV-seroprevalence in Chiquinquirá (20.20%). In Ubaté, re-use of needles was identified as a risk factor, contaminated blood in needles is considered one of the main routes of transmission. On the other hand, manual milking was identified as a risk factor in San Miguel de Sema. Conclusion: The non-implementation of an individual needle per animal in Ubaté; the Holstein breed and manual milking in San Miguel de Sema were identified as risk factors for the presence of antibodies against the disease. EBL prevention and control plans should be established that focus on the implementation of management and sanitary practices based on herd biosecurity.

Serodiagnosis and Risk Factors Associated with Infectious Agents of Reproductive Diseases in Bovines of Chiquinquirá, District of Boyacá (Colombia).

The productivity of cattle farms is affected by infectious and noninfectious factors that generate economic losses and cause reproductive failure represented by low conception rates, embryonic mortality, abortions, and fetal mummification. The infectious agents that most impact the reproductive health of the bovine species from conception to birth are bovine herpesvirus type 1 (BoHV-1) causing infectious bovine rhinotracheitis (IBR), bovine viral diarrhea virus (BVDV), bovine parainfluenza virus type 3 (PI3), Neospora caninum and Leptospira spp. The objective of this study was to diagnose the presence of BoHV-1, bovine viral diarrhea (BVD), PI3, Neospora caninum, and Leptospira spp. by serology and identify the risk factors associated with infectious agents of reproductive interest in bovines of Boyacá (Colombia). A descriptive cross-sectional study was developed, with simple random sampling, where a sample size of 601 female cattle of Holstein, Jersey, and Normande breeds of different age groups was determined. Blood samples were taken and processed using the indirect ELISA technique (SYNBIOTICS®, SERELISA® BVD p80 Ab Mono Blocking, Ingezim R.12.NC.K, PRIMACHECK VPI-3®) and the MAT test for the diagnosis of bovine leptospirosis. The data were processed with the statistical program Epi Info™. The highest apparent seroprevalence was established for infectious bovine rhinotracheitis (61.1%), followed by BVD (37.6%), PI3 (40.9%), neosporosis (51.1%), and leptospirosis (14.8%). Variables such as age >4 years and Holstein breed for IBR and >4 years for BVD were established risk factors. Considering our results, we suggest implementing prevention and control plans that include vaccination as a prophylactic measure and biosecurity tools that reduce the probability of contagion and transmission of pathogens.

Seroprevalence of bovine viral diarrhea virus (BVDV) in cattle from Sotaquirá, Colombia.

Worldwide distributed Bovine Viral Diarrhea Virus (BVDV) represents a high risk of infection in most bovine farms, in which it is associated with gastrointestinal, respiratory, and reproductive diseases. The purpose of this research was to establish the seroprevalence and the main risk factors associated with the presentation of BVDV in the municipality of Sotaquirá, Colombia. Samples were taken from 1000 cattle of Holstein, Ayrshire, Jersey, Normande Gyr and Holstein x Gyr. Epidemiological surveys were implemented, reproductive and management variables were taken into consideration. Indirect ELISA was performed to detect specific antibodies against BVDV using the commercial kit SERELISA® BVD p80 Ab Mono Blocking. The overall seroprevalence of antibodies against BVDV was 42.5% (425/1000), where the Gyr breed (59.1% apparent prevalence (AP); 60.3% real prevalence (PR)) and the age group > 4 years (53.0% PA; 54.4% PR) presented the highest seroprevalences. A significant statistical association was found for the breed, age, management practices evaluated and the presentation of PI3 (p ≤ 0.05). Age group > 4 years, Normande breed, presentation of PI3 and grazing lease were established as risk factors associated with BVDV in the herds. These infections are mainly associated with dairy cattle and herds with many animals, so it is important to consider vaccination plans as a preventive system and follow up on the most common diseases.