Evaluation of the risk factors influencing the spread of caseous lymphadenitis in goat herds.

Epidemiological studies on caseous lymphadenitis were carried out in Poland in 1996 and 2002 among goat herds covered by a milk recording program. Between-herd seroprevalence was 13.2% in 1996 and increased to 62.5% in 2002. The average size of seropositive herds was statistically significantly higher than that of seronegative ones, however there was no statistically significant difference in the age between the herds. A statistically significant prevalence ratio (PR) was identified and relevant attributable risk for exposed animals (AR(exp)) was calculated for the following risk factors: presence of seropositive males in a herd (PR = 8.350; AR(exp) = 0.651), presence of superficial abscesses in animals (PR = 6.142; AR(exp) = 0.620), presence of respiratory signs (PR = 2.900; AR(exp) = 0.393), presence of animals in poor condition in a herd (PR = 2.774; AR(exp) = 0.390) and occurrence of reproductive failures in a herd (PR = 1.798; AR(exp) = 0.230). Purchase of animals from abroad, mastitis and husbandry conditions (housing system, grazing system, hygienic conditions) were not shown to be statistically significant risk factors.