Abstract :
The objectives of the study were to determine a practical method of using predetermined
sexed semen in Sika deer (Cervus nippon). Semen was collected by electro-ejaculation from
two Sika stags and transported to the laboratory and separated into X- and Y-chromosomebearing
sperm after analysis and re-analysis (using a modified high-speed cell sorter), or
control (unsorted) semen. Eighty-four Sika hindswere inseminated with 2.8×107 unsorted
(control) or 2.3×106 sorted (X or Y) frozen-thawed semen via intra-uterine laparoscopy
58–66 h after removal of intra-vaginal progesterone-impregnated CIDR devices and the
administration of 330 IU PMSG at the time of CIDR removal. No significant differences in
the post-thaw motility of control (43.4±4.4%), X- (45.3±4.5%) and Y-sorted (43.5±3.2%)
samples were recorded. The sorted frozen-thawed sperm (X, 72.5±6.4%: Y, 75.2±5.5%)
recorded significantly (P < 0.05) more intact acrosomes following thawing than the unsorted
frozen-thawed (68.2±10.2%) sperm. The individual Sika stags had no effect on the postthaw
sperm motility. Sorted frozen-thawed sperm demonstrated a significantly shorter
survival time after thawing than the control sperm (P < 0.05). The number of Sika hinds
pregnant following insemination with unsorted or control thawed sperm was significantly
higher (33/42; 78.6%) than for hinds inseminated with either X- (5/11; 45.5%) or Y-sorted
sperm (15/31; 48.4%). Ultimately 14 out of the 15 calves produced by Sika hinds inseminated
with Y-sorted sperm were male (92.9%) and 5/5 calves (100%) from Sika hinds inseminated
with X-sorted spermwere female. The sex ratio of the calves born to hinds inseminated with
sex-sorted sperm significantly (P < 0.05) deviated for the 48.5% (female, 16/33) and 51.5%
(male, 17/33) in the control group. All calveswere born between 230 d and 243 d of gestation.
Male and female calves in the control group had similar birth andweaningweights as calves
from hinds inseminated with X- or Y-sorted sperm. In conclusion it can be said that normal
calves of the predicted sexmay be produced after intra-uterine insemination conducted by
laparoscopy with low numbers of sex-sorted cryopreserved Sika sperm.
