Abstract :
Evidence is provided of seasonal changes in the rate of DNA fragmentation dynamics of
sperm collected from goats Murciano-Granadina breed), in a Spanish Breeding Centre at
41◦N latitude. Results show that the initial assessment of sperm DNA fragmentation (T0)
was not sufficient to differentiate sperm DNA fragmentation of bucks collected at different
times of the year (Kruskal–Wallis 2.399; P = 0.493). However, when thawed semen was subsequently
incubated at 37 ◦C for periods of between 2 and 48 h, differences were recorded
in the rate of sperm DNA fragmentation (r-SDF), that are indicative of seasonal changes in
reproduction (Log Rank: Mantel–Cox; 2 = 158.6; DF = 3; P < 0.001). Goat semen collected
and cryopreserved in the Spanish winter and spring resulted in a poor post-thaw sperm
DNA longevity and recorded a r-SDF of 0.8 and 1.3 per hour, after 48 h of incubation respectively.
The r-SDF subsequently decreased to 0.16 and 0.36 per hour during summer and
autumn. It is therefore, recommended that semen samples from Murciano-Granadina goats
housed above the 40◦N latitude be collected and cryopreserved in the summer and early
autumn. This would result in a more stable DNA molecule, which is likely to improve the
reproductive success.
