A serological survey and study on the effects of Caprine Arthritis-Encephalitis Virus infection on reproductive performance of goats in the western part of Thailand

Abstract

During the period from November 2009 to January 2011, a cross-sectional serological survey was carried out in three western provinces of Thailand. A total of 1,129 serum samples from 74 randomly selected goat farms were collected and seroprevalence of antibodies to CAEV infection was determined using competitive enzyme-linked immunosorbent assay (cELISA) test. Semi-structural questionnaires were developed and presented to farm owners. Univariable analysis by Chi-square test was employed to find out the association between CAEV infection and each exposed factor. Multivariable logistic regression model was run to clarify the risk factors. A total of 67 goats (5.9%) were found seropositive with true prevalence of 5.5%. 23 farms out of 74 were found seropositve showing the prevalence of 31%. On herd prevalence, herd type (p = 0.034; OR = 5.026; 95% CI = 1.130-22.360), herd size (p = 0.006; OR = 24.065; 95% CI = 2.466- 234.788), contact with goats from other herds (p = 0.008; OR = 8.526; 95% CI = 1.762 - 41.25), and addition of new goats into herd (p = 0.044, OR = 4.396; 95% CI = 1.044 – 18.51) were observed as risk factors to CAEV infection. On individual prevalence, age of 3 years and above (p = 0.001, OR = 4.288, 95% CI = 1.809 – 10.163), herd size (p< 0.001, OR = 17.971, 95% CI = 7.787 – 41.475), and addition of new goats into herd were detected as risk factors. The results showed that CAEV infection prevailed among the goat herds in the western part of Thailand, with some risk factors to be aware of. A comparative study between two groups of animal, a seropositive and a seronegative group, regarding their reproductive performance in response to CAEV infection was performed in a CAEV seropositive dairy goat farm during the period from January 2010 to February 2011. Average number of offspring born to each group was higher in seronegative group as compared to seropositive group (1.63 vs 1.50). A significantly low (p<0.05) first conception rate was observed in seropositive group, and total conception rate was higher in seronegative group than in seropositve group (82.6% vs 50.0%). Failure to conceive during two consecutive AI was more frequent in seropositive group than in seronegative group (25% vs 13%). These findings suggested some evidence of adverse effects of CAEV infection on reproductive performance of goats and further in-depth studies with greater sample size are deemed necessary to define the influencing effects of CAEV infection on reproduction in goats more precisely.