VIe CONG. INTERN. REPROD. ANIM. INSEM. ARTIF., PARIS, 1968, VOL. !

TABLE 5

Effect of age of bovine semen during storage at about -79°C on
fertility and on embryonic mortality as estimated by the 46-167
day nonreturn difference (Expt. 11, 1962-63).

     

Age of semen : e RREk, Teye) Ag;l?thi:
insem, at 167 days, % A feraiia. &
< | month 8,543 66.4 13.4
1-2 months 50,235 68.0 10.0
2-3 months 40,767 67.8 9.3
3-4 months 23,648 67.8 9.0
4-5 months 14,120 66.7 9.1
5-6 months 9,088 66.4 9.2
> 6 months 30,031 54.7 13,1
Total 176,432 65.4 10.3
TABLE 6

The decrease in fertility (mean difference in 167-day nonreturns
between 1-2 month storage and > 6 month storage) on aging of semen
at about -79°C for the months in the year of insemination (cow
response) and of semen collection (bull response).

Cow response Bull response
Month Decrease on > Decrease on >
6 mo. storage 6 mo. storage
January 13.8 7.0
February 13.8 11.8
March 16.6 8.4
April 1325 S
May 12.8 16,8 %**
June 13.2 Y65 155
July FI=3 20,92~
August 14.4 F4 2280
September 1'ed eNihr s
October 1551 15.7%%
November 14.6 12.8
December 14.7 8.9
Total insem. 174,307 176,432
Mean decrease 133 1353

*¥p = 0,01 that difference from mean is not due to chance.

1203