Veterinary scientists in Chile are testing a contraceptive vaccine for dogs, for use on both male and female pooches, which they say will help reduce the problem of pet over-population. Roselle Chen reports.
To help get a handle on Chile's growing dog population, scientists have come up with an inexpensive canine birth control option. Scientists from the University of Chile Veterinary and Livestock Faculty developed a vaccine from an existing formula used to sterilize pigs, as professor Leonardo Saenz explains. (SOUNDBITE) (Spanish) LEONARDO SAENZ, UNIVERSITY OF CHILE VETERINARY AND LIVESTOCK FACULTY, SAYING: "It began in Australia more or less in 1989. What we did was to take the concept of immuno-castration which already existed and we developed and improved for use in domestic animals, mainly in dogs, and to create an alternative for pigs, better than what already exists. The previous one was a vaccine by a pharmaceutical laboratory which needs two doses to take effect. In our case, only one dose is needed for the vaccine to take effect." According to Saenz, the vaccine's effect is similar to that of a surgical castration without needing the resources and subsequent care required by an operation. It's also a reversible measure based on hormonal alterations and has no side effects, unlike other forms of contraception. (SOUNDBITE) (Spanish) LEONARDO SAENZ, UNIVERSITY OF CHILE VETERINARY AND LIVESTOCK FACULTY, SAYING: "Since it is a vaccine which blocks the production of hormones, it does not function as a contraceptive but rather an immuno-castrator. The difference is that contraceptives prevent animals from going on heat. It will still engage in reproductive activity but it will not be able to fertilize. In this case, there are no hormones so there is no activity, there are no gametes so the animal is sterilized as a result of suppressed hormones. As there is a reduction in the hormonal activity, there are no side effects as is the case with hormonal contraceptives on which they put high quantities of contraceptive or hormones which induce alterations in the uterus and can be related to the appearance of some cancers. In this case that does not happen, we block that activity." Veterinary scientists hope the vaccine will help to control the growing canine population in Chile, where surgical castration is only applied in small numbers. They expect the vaccine could be administered to a group three or four times greater than those that undergo surgery. The vaccine has been patented in Chile, Europe and the United States, and is undergoing further tests in controlled conditions.