IMMUNOPROPHYLAXIS OF CAPRINE CONTAGIOUS AGALACTIA DUE TO MYCOPLASMA-GALACTIAE WITH AN INACTIVATED VACCINE

The aim of this study was to control endemic contagious agalactia due to Mycoplasma agalactiae in a semi-extensive goat herd by means of vac cination with an inactivated vaccine. Groups of 400 goats were vaccina ted one month before and three months after parturition (group A), one month before and four months after parturition (group B), and two mon ths and one month before and three months after parturition (group C). The experiment continued over six lactations and natural infections m ere monitored clinically, immunologically and microbiologically. After the sixth lactation there were no significant clinical differences be tween groups A and B but there were significant differences between th ese two groups and group C. The levels of growth-inhibiting antibodies ranged from 1:20 to 1:80 in groups A and B and from 1:40 to 1:160 in group C. The numbers of goats excreting mycoplasmas decreased to a gre ater extent in group C than in groups A and B. A natural infection ind uced an outbreak of contagious agalactia in group B. An experimental i nfection with 10(6) cfu affected seven of 10 goats in group A (two ser iously) and two goats in group C moderately. It is recommended that th ree doses of vaccine should be administered before, and one dose after each parturition, and that the herd should be kept isolated in order to control the disease.