A new antibiotic combination for frozen bovine semen, 3. Evaluation of fertility.

Field fertility (nonreturn rate) studies were performed independently by three artificial insemination organizations to evaluate bovine semen processed for freezing using the antibiotics gentamicin, tylosin and Linco-Spectin at concentrations of 500 ug, 100 ug, and 300/600 ug, respectively, per milliliter of neat semen and per milliliter of nonglycerol portion of the extender. The antibiotic combination including penicillin, dihydrostreptomycin, polymyxin B sulfate, with/without Linco-Spectin (500 units/ml, 2000 ug/ml, 1000 units/ml and 300/600 ug/ml, respectively) was used as the control treatment. Results indicated no significant effect on seminal quality as measured by field fertility under the conditions of these experiments using heated whole milk or egg yolk-sodium citrate seminal extenders. Use of the new antibiotic combination has been adopted by Certified Semen Services.