FACTORS ASSOCIATED WITH USE OF PROSTAGLANDINS IN REPRODUCTIVE HERD HEALTH-PROGRAMS FOR DAIRY-COWS

Use of prostaglandin F-2 alpha products (PG) in dairy cows was studied by use of computerized reproductive herd health data compiled from 29 dairy herds in Minnesota and Wisconsin during 1983 through 1988. Trea tment with PG was recorded in 1,856 of 7,139 (26.0%) complete lactatio ns. More than 1 treatment with PG was administered in 534 of the 1,856 (28.8%) lactations in which PG were used. The proportion of lactation s in which treatment was used varied among herds and years, and was as sociated with the proportion of cows in which natural breeding was att empted and, to a lesser extent, with estrus detection index and concep tion rates; these associations were potentially modified by time betwe en veterinary herd health visits. Calving-to-treatment intervals (mean +/- so) were 100.4 +/- 55.1 days for first treatments only, and 116.2 +/- 66.1 days for all treatments. These values varied considerably am ong herds and years and among reasons for treatment. Much of the varia tion in proportions of lactations in which treatment was used and in t he time of treatment within lactations could not be accounted for with the variables included in this study, and was probably related to ind ividual considerations for each cow.