A study was conducted to determine whether concurrent administration of
vaccines for reproductive diseases and an
anthelmintic, given immediately prior to estrus synchronization with a
progestogen, would affect subsequent estrous response and fertility in beef heifers. Two hundred ninety-five yearling crossbred beef heifers on 3 ranches in Oregon and Kansas were assigned to 1 of 2 treatments. Control heifers were vaccinated and dewormed 30 d prior to the anticipated breeding. Treated heifers received the same vaccination and deworming products 9 d prior to breeding. All heifers in both groups were treated with
norgestomet (
Syncro-Mate-B) for 9 d to synchronize estrus. The administered
vaccine consisted of modified live virus for
infectious bovine rhinotracheitis,
parainfluenza and bovine viral
diarrhea, with 5-way
bacterin for
leptospirosis and
bacterin for
vibriosis. Heifers were also administered
ivermectin or
fenbendazole for deworming. Heifers exhibiting synchronized estrus were artificially inseminated and subsequently exposed to fertile bulls. Pregnancy status was determined at a later date by palpation per rectum. Vaccination and deworming at the time of treatment with
progestogen compared with immunizing and deworming 30 d prior to breeding did not impair the expression of behavioral estrus. The percentage of treated heifers conceiving to AI or natural service did not differ from that of the respective control heifers. These data suggest that vaccination, deworming and synchronization of estrus with
norgestomet can be performed simultaneously without any detrimental effects upon occurrence of behavioral estrus or fertility.