Stallion spermatozoa selected by single layer centrifugation are capable of fertilization after storage for up to 96 h at 6°C prior to artificial insemination

Table 1 Outcome of artificial insemination with SLC-selected sperm doses stored for 48–96 hours (n = 16)

Mare	Stallion	Time of AI after semen collection and SLC (h)	Sperm dose (x10⁶)	Conceptus detected by ultrasound	Age of spermatozoa at time of ovulation (h)
1	B	48	500	Yes	65
2	D	48	500	Yes	60
3	F	48	500	No	83
4	F	48	500	Yes	83
5	F	48	500	Yes	60
6	A	72	500	No	113
7	A	72	500	No	AI after ovulation(< 12 h)
8	C	72	500	Yes	87
9	B	72	500	Yes	80
10	D	72	500	Yes	112
11	E	72	350**	Yes	AI after ovulation(< 12 h)
12	F	72	500	No	120
13	B	96	500	Yes (twins)	111
14	C	96	500	Yes	110
15	C	96	500	Yes	110
16	C	96	500	No	156

One additional mare, inseminated with semen from stallion A at 48 h after SLC, had already ovulated for more than12 h by the time of AI. She did not become pregnant, which may have been due to the interval between ovulation and AI.
** only 350 x10⁶ spermatozoa were available from stallion E.

ISSN: 1751-0147