EFFECT OF hCG BEFORE, DURING AND AFTER INDUCED ESTRUS ON CONCEPTION AND PROGESTERONE IN REPEAT BREEDER COWS

Abstract

The repeat breeding syndrome in cows is the most commonly encountered and poorly understood
condition causing economic loss to the farmers. A total of 64 repeat breeder cows were treated with
0.98 mg of Tiaprost on day 10 following natural estrus and were equally divided into 4 groups as PGN,
PG-P, PG-O and PG-E and were treated with no hCG, 1500 IU hCG at 24 hrs before first Al, at first
Al and at 4 days following first Al, respectively. Sixteen untreated repeat breeder cows served as
control. In the treated cows Al was done at 72 (first Al) and 96 hrs {Second Al) after PGF20 injection. In
control group, Al was carried out twice at 24 hrs interval in natural estrus. Blood was collected at
different phases of treatment for progesterone assay. First service conception rates obtained were
43.75, 43.75, 62.50 and 37.50 percent in PG-N, PG-P, PG-O and PG-E, respectively and the same in
control was18.75 per cent. The O¥erall mean level (ng/ml) of serum progesterone at the time of natural
estrus, PGF2
a injection, induced estrus and at 2nd
, 4th and 6th day following first Al in cows which
became pregnant was 0.36±0.08, 7.19±0.46, 0.18±0.05, 1.05±0.20, 1.70±0.22 and 3.37±0.77 and
corresponding values in non pregnant cows were 0.51±0.09, 5.24±0.43, 0.23±0.03, 0.57±0.15, 0.99±0.27
and 1.62±0.26, respectively. It is concluded that PGF2a in combination with hCG at Al, improved the
conception rate in repeat breeder cows.