Reproductive safety of vaccination with Vista 5 L5 SQ near breeding time as determined by the effect on conception rates.

Replacement heifers (N=799; 10 to 13 months of age) were vaccinated with Vista 5 L5 SQ (Intervet; a reconstituted vaccine-bacterin product containing modified-live cultures of infectious bovine rhinotracheitis [IBR] virus, bovine viral diarrhea virus [BVDV; types 1 and 2], parainfluenza-3 virus, and bovine respiratory syncytial virus and inactivated cultures of Leptospira serovars canicola, grippotyphosa, hardjo, icterohaemorrhagiae, and pomona with a proprietary adjuvant) at either 40 plus/minus 5 days (control; n=399) or 3 days (test; n=400) before peak breeding day. By 40 plus/minus 5 days before peak breeding day, heifers in both groups had greater average titers to IBR, BVDV types 1 and 2, and four of the five Leptospira antigens assessed as compared with prevaccination titers on day -90 plus/minus 25 days. Conception rates were not affected by treatment. This study suggests that conception rates will not differ between heifers vaccinated with Vista 5 L5 SQ 3 days before breeding and those vaccinated approximately 40 days before breeding.