Calf Talk

September, 2006

Volume 12, No. 9

VISTA -INTERVET’S NEW MODIFIED LIVE

By: Russ Schnepper, D.V.M.

Intervet’s Vista 5 SQ is an effective modified live virus vaccine. I have always said “all the modified live virus vaccines work.” What I was referring to in making this statement has to do with the way I had always used modified live vaccines in the baby calf. My primary purpose was to have the vaccine cause the calf’s own immune system to fire up and produce interferon. Interferon is mother nature’s own medicine to cure whatever ails the calf. The interferon would last for about three days and this would give the calf some protection to cover the stress of moving and meeting his new pen mates.

Until recently blood titers had been used to demonstrate immunity produced by a vaccine. This is known as humoral immunity. It is a measure of antibodies. Now there is another measure used to assess the cell mediated response, which appears to be more important in the prevention of disease than the mere presence of antibodies. Vista vaccines were able to produce cell mediated immunity to IBR, BRSV, and BVD types 1 and 2. The studies were run on colostrum deprived calves. However, the Vista SQ vaccines also produce immunity in the presence of colostral antibodies.

Intervet has a single dose claim for immunity to BRSV for out to six months post vaccination. The other vaccines, as far as I have been informed, require two doses to get immunity to BRSV. This is an important point for me, as I have had client’s calves break with acute BRSV resulting in sudden deaths in 300 to 600 pound steers, that had been given at least three doses of other brands of modified live virus vaccines.

Vista’s demonstrated ability to produce measurable levels of cell mediated immunity to both BVD types 1 and 2, in the young calf is very significant. If you have just one PI (Persistently Infected with BVD type 2 virus) calf in a group of calves, it will be shedding BVD virus every day of its life. A PI, or persistently infected, calf occurs when the calf’s dam has BVD virus circulating in her body during the first trimester of her pregnancy. The virus also gets into the uterus and subsequently into the developing fetus. The fetus itself has its own immune system developing at this time. As a result the calf’s own immune system thinks the BVD virus is part of its own body and does not make antibodies against it. It will never make antibodies against BVD nor a BVD virus vaccine for its entire life. (This is a slight over simplification, but I hope this makes it understandable.) It is very important the rest of the calves in the group have protection against type 2 BVD.

Intervet’s studies show a superior immunity develops from a subcutaneous administration of the vaccine over an intramuscular injection. Vista SQ is licenced for injection under the skin. I prefer you inject it under the skin in the neck. Incidentally studies show that vaccines injected into the skin intradermally give superior immunity with a lower dose of vaccine. Work is being done to develop needles, syringes, and a technique to do this.

Vista Once SQ is a combination of the Vista 5 virus and the Once PMH. It is now packaged in two bottles (the freeze dried vaccine powder in one and the diluent in another) rather than the old three bottle combination.

Vista 5 SQ is smoother and does not cause the calf to go through a sweat as some MLV vaccines do. I really like the new Vista SQ vaccine, and so will your calves.

Contact information for ordering information and questions about our products:

Schnepper International, Inc.

3210 County B, Platteville, WI 53818

608-348-6141, Fax: 608-348-6146