Influence of Caprine Arthritis Encephalitis Virus infection on milk production of French Alpine goats in Croatia

We have investigated the influence of infection with Caprine Arthritis Encephalitis Virus (CAEV), developed clinical arthritis and recorded subclinical mastitis on the length of lactation, milk yield and its composition per lactation. The study was carried out on the sample of 808 goats of French Alpine breed from production farms in Croatia. Samples of blood were taken for serological tests and milk samples for subclinical mastitis detection. Presence of clinical arthritis was noted by inspection and palpation of the joints. Lactation and production data were collected by Croatian Agricultural Agency. The influence of infection status for CAEV and clinical arthritis, separately, were tested on milk yield, length of lactation and milk composition (fat, protein and lactose) using GLM procedure for models including the year of measurement, lactation number of the animal and subclinical mastitis record. CAEV was serologically confirmed in 53.72 % of the total number of goats. From the total sample 23.08 % were infected with CAEV with confirmed subclinical mastitis of bacteriological etiology. In addition, 22.47 % of the total sample had clinical arthritis. Of the total sample 16.95 % were CAEV infected and with diagnosed clinical arthritis. Influence of virus infection was confirmed on all of the analyzed traits, with lower production results. Clinical arthritis had significant influence on decrease in most of analyzed traits, exceptions being total milk, fat amount (%) and lactose content (%) and amount (kg). Diagnosed subclinical mastitis was not found to be significant influence in models of duration of lactation, or fat, protein and lactose content (%).