title: Relationship between final temperature, thaw rate, and quality of bovine semen.
abstract: Relationships between thaw rate, thaw bath time, and initial bath and final seminal temperature with coefficients of determination .99 and .97 were: bath time = -.01 + 220.25(1/thaw rate); initial bath temperature = final seminal temperature - 7.29 + 390.05 (1/bath time). Ejaculates from 10 bulls were split and processed in egg yolk-citrate-glycerol, egg yolk-Tris-glycerol, and whole milk-glycerol. All semen was packaged and frozen in .5-ml French straws at -196 degrees C. Sixteen thaw treatments consisted of factorial combinations of four final seminal temperatures and four thaw rates. Treatments were assessed by post-thaw acrosomal integrity after 3-h 37 degrees C incubation. Seminal quality improved with increasing final seminal temperature up to 31 degrees C and did not differ between 31 and 44 degrees C for any of the extenders. A slow thaw rate (3 degrees C/s) resulted in inferior quality for all extenders, and rates 11, 19, and 27 degrees C/s resulted in similar quality for citrate and milk extended semen. Acrosomal integrity was most for 19 degrees C/s in Tris extended semen. A significant factorial interaction existed for Tris and milk extended semen. Predicted acrosomal response of 57.7% across all extenders was at optimum final seminal temperature and thaw rate 37 degrees C and 18 degrees C/s. Bath temperature and bath time determine optimum thaw rate and final temperature of semen packaged in French straws and thus maximize seminal quality.
mesh_terms: D000177:Acrosome / Q000502:physiology; D000818:Animals; D002417:Cattle; D002951:Citrates; D019343:Citric Acid; D005298:Fertility; D005615:Freezing; D008297:Male; D008892:Milk; D008954:Models, Biological; D012044:Regression Analysis; D012661:Semen / Q000502:physiology*; D012662:Semen Preservation / Q000662:veterinary*; D013696:Temperature; D013997:Time Factors; D014325:Tromethamine
chemical_list: D002951:Citrates; D014325:Tromethamine; D019343:Citric Acid