Abstract

Gael García Quinn*, Guillermo González Iñárritu , Anthony Carlos Toro , Lupita Huerta Santana

The purpose of the study was to estimate seroprevalence of four reproductive diseases: brucellosis, bovine virus diarrhea (BVD), neosporosis and bovine respiratory rhinotracheitis (IBR) in dairy cattle in Mexico. In a stratified multi-stage design, 4,487 serum samples were collected in 182 herds from different states of Mexico. Epidemiologic and spatial information was also collected to evaluate risk factors and elaborate maps of risk. Overall seroprevalence rates were: Brucellosis 14.7% (with the Rose Bengal test) and 5.1% (with the radial immunodifusion test), BVD 78.8%, neosporosis 36.8% and IBR 73%. The highest prevalence for neosporosis (46%) and brucellosis (21.8%) was observed in the intensive system. In the familiar and double-purpose systems, the prevalence was 34 and 15.8%, respectively. No big differences were observed for IBR and BVD in the three systems, 69 to 75% for IBR and 63.9 to 87.8% for BVD. The states with the highest prevalence for brucellosis were Hidalgo (77%), Aguascalientes (36%), Guanajuato (30%), and La Laguna (Coahuila and Durango) (17%). Prevalence was low in Veracruz (1%), Chiapas (2%), and Sinaloa (3%); for BVD ranged from 55% (in the state of Sinaloa) to 98% (in the state of Aguascalientes). Prevalence for neosporosis was high in Hidalgo (55%), Guanajuato (53.7%), and Querétaro (47.9%). Risk factors associated to prevalence of brucellosis were: herd size, introduction of animals from different herds, common sheds, production system, and source of replacements. For BVD, herd size, common sheds, intensive production, and large calving intervals were significant factors. Abortion rate, use of fresh colostrum, services per conception, and intensive production were the factors associated with neosporosis. Factors significantly associated to IBR were: use of bull for breeding, and positive serology to parainfluenza virus 3. Areas of risk and probability of disease were related with areas of high density of dairy cattle.