A Comparison of Diluents and Cryopreservatives for Freezing Turkey Semen

Two pre-freeze handling procedures, early cooling of turkey semen to 3–5°C. and late cooling by holding semen at 15°C., were compared in 2 replicates with respect to post-freezing sperm motility. Semen was diluted 1:5 in seven diluent cryopreservative combinations (Lake’s diluent, Lake, 1968) with 13.64 g. glycerol/100 mls. (1) and 7% ethylene glycol (2); Brown’s diluent (Brown, 1975) with 13.64 g. glycerol/100 mls. (3) and 7% ethylene glycol (4); Extender I (5), and Extender II (6) (Macpherson et al., 1969) and a diluent (7) reported by Rajamannan (1968) and frozen at 7°C. per min. to −196°C. After thawing, the samples were held at either 0° or 41°C. for 0, 2 and 4 hr. of storage. Motility scores were higher for late than early cooling at 2 (P<0.05) and 4 (P<0.01) hr. storage at 0°C. in the first replicate but there were no differences in the second replicate. Sperm motility was lower for semen held at 41°C. than 0°C. The seven diluent-cryopreservative combinations were evaluated with respect to maintaining fertility of turkey semen after freezing. Glycerol was removed after freezing before insemination. After weekly inseminations (10 hens per diluent) for 4 weeks, Extender II (6) had the highest percent fertility (P<0.05) (1 = 3.7%; 2 = 9.1%; 3 = 10.6% ; 4 = 5.6%; 5 = 9.2%; 6 = 20.7%; 7 = 6.9%). Extender II also had the longest duration of fertility (1 = 0d. ; 2 = 2d. ; 3 = 30.5d.;4 = 3.5d.; 5 = 12d.; 6 = 48d.; 7 = 15d.) and best fertility during duration (1 = 0.0%; 2 = 1.1%; 3 = 9.8%; 4 = 4.6%; 5 = 6.9%; 6 = 15.1%; 7 = 5.0%) being significantly (P<0.05) better than all others except Brown’s plus glycerol (3). In a third trial the effect of not removing glycerol from diluents 5 and 6 was compared to the best two diluents of the above (3 and 5) with the glycerol removed. There was no difference (P>0.05) with respect to percent fertility (2.0%; 4.6%; 1.4%; 2.4%, respectively), although Extender II without deglycerolization gave the highest fertility.