Effect of luteolysis on control of ovarian follicles using
oestradiol benzoate and progesterone in cattle
C.R. Burke, S. Morgan, B.A. Clark and F.M. Rhodes
Dairying Research Corporation Ltd, Private Bag 3123, Hamilton.
Proceedings of the New Zealand Society of Animal Production. 1998,
58: 89-91
This study aimed to determine whether progesterone from
intravaginal insertion of a CIDR device could substitute for luteal
progesterone and facilitate oestradiol benzoate (ODB)-induced control of
ovarian follicle waves in the event of luteolysis. Luteolysis was
induced by an injection of prostaglandin-F2alpha on Day 13 of the oestrous
cycle in 24 lactating dairy heifers. Concurrent treatments on Day 13
were: i) 1 mg ODB i.m. (ODB1); ii) CIDR for 6 days (CIDR); iii) 1 mg ODB
i.m. plus CIDR for 6 days (ODB1/CIDR); or, iv) 2 mg ODB i.m. plus a CIDR
for 6 days (ODB2/CIDR). Examination of the ovaries using ultrasonography
showed that oestrous cycles comprising 2 follicle waves predominated
among ODB1 and CIDR groups; whereas combination treatments produced
mostly 3-wave cycles (p<0.05). Day of ovulation was 15.4 ± 0.3, 21.2 ±
0.2 and 22.5 ± 0.2 for ODB only, CIDR only and 1 or 2 mg ODB plus CIDR
cows, respectively (p<0.01). The interval from day of emergence to
ovulation of the ovulatory follicle was less (p<0.01) in cows treated
with ODB only (6.0 ± 0.3 days), or ODB plus a CIDR (7.2 ± 0.6 days),
compared to a longer interval in those receiving a CIDR only (11.0 ± 0.8
days). These results showed that progesterone from a CIDR device was
able to facilitate ODB-induced follicle wave turnover at the time of
luteolysis in lactating dairy heifers.
Keywords: NZSAPAB;
Ovarian follicles; progesterone; oestradiol benzoate; cattle.
Last Updated 12-09-1998
