Use of Synovex-H as a Method for Androgenizing Heifers for Teaser Animals

Abstract

Detection of estrus is the most costly factor contributing to reproductive efficiency in dairy cattle (1, 2, 3). In Colorado alone, the potential economic loss from poor detection of estrus to the dairy industry is from $123 to $205 per cow per year (4). The use of teaser animals as an aid in the detection of estrus has generally been proved advantageous (5). Teaser animals are usually surgically altered intact males or androgenized females. The use of an intact male although surgically altered does not eliminate the potential of venereal disease transmission. In addition, the cost of surgical altering and time lost until the teaser animal can be used must be considered. Androgenizing heifers has proven effective. The accepted procedure has been intramuscular injections of 200 mg of testosterone every other day for 20 days plus biweekly boostering with testosterone injections (5, 6, 7). A simpler approach would be to use an implant containing testosterone to get a longer duration of activity in the androgenized heifer. This presentation will detail the preliminary results on the use of this procedure.