The objectives of this study were to determine the efficiency of controlled
internal drug release (CIDR) to synchronize estrus in cow, and to study the success rate
of estrus synchronization and fertility responses with respect to animal’s breed, farming
system and body condition score (BCS). The study was conducted between January
2007 to December 2008 in three private farms in Gua Musang, Kelantan. The cows
aged between 3 to 7 years old were of Charolais crossbreds (n=52), Brahman crossbreds
(n=13) and Kedah-Kelantan (n=37) breed. All cows were subjected to estrus
synchronization with CIDR. On day 0, CIDR implant with estradiol benzoate capsules
were inserted into the vagina of the cow. On day 8, estradiol benzoate was injected, 24
hours prior to insemination with frozen semen provided by the Department of
Veterinary Services, Kelantan. Blood samples (10 ml) were collected by using jugular
venipuncture on day 0, 3, 7, 8, 9, 12 and 14 of the experiment. Pregnancy diagnosis was
carried out on day 60 post-insemination by rectal palpation.
Body Condition Score (BCS) for cows in intensive farm (4.59±0.22) was
significantly higher (p<0.05) when compared to cows in semi-intensive (3.76±0.14) and
integration farms (3.42±0.12). Cows in Intensive (59%) and semi-intensive (59%) farms
showed significantly higher percentage of pregnancy for fixed time insemination than
that of cows in integration farm (37%). Charolais crossbreds breed had better BCS (4.65
± 0.18) than Brahman crossbreds (4.03 ± 0.11) and Kedah-Kelantan (3.43 ± 0.09) bred,
respectively. Charolais crossbreds showed significantly higher percentage of pregnancy
to fixed time insemination (58%) when compared to Brahman crossbreds (54%) and
Kedah-Kelantan (49%) bred (p<0.05). The percentage of pregnancy for cows with BCS
4 (53%) and 5, 6, 7 (69%), were significantly higher than cows with BCS 3 (43%).
Cows with ≥ 55 days of postpartum interval had significantly higher percentage of the
estrus (75%) and pregnancy (62%) than cows with < 55 days of postpartum interval.
On day 0, progesterone level was 3.16±0.74 ng/ml for all bred of cows and
reached the peak on day 3 (12.75±1.21 ng/ml). Level of progesterone started to decline
on day 3 and the lowest level was observed on day 12 (1.37±0.48 ng/ml). Progesterone
levels on day 0 were 7.47±1.13 ng/ml, 0.52±0.09 ng/ml, and 3.13±0.92 ng/ml, for
Charolais crossbreds, Brahman crossbreds and Kedah-Kelantan breeds, respectively.
Progesterone level was highest on day 3 for Charolais crossbreds (6.21±1.25 ng/ml),
Brahman crossbreds (9.03±3.73 ng/ml) and Kedah-Kelantan (27.16±5.36 ng/ml). On
day 0, estradiol level was 3.27±0.55 pg/ml for all bred of cows and reached the peak on
day 9 (43,47±7.88 pg/ml). Estradiol levels were 0.00±00 pg/ml, 5.01±0.90 pg/ml, and
4.60±0.61 pg/ml, for Charolais crossbreds, Brahman crossbreds and Kedah-Kelantan
breeds, respectively on day 0. Estradiol level was highest on day 9 for Charolais
crossbreds (77.26±1.89 pg/ml), Brahman crossbreds (34.20±1.48 pg/ml) and KedahKelantan (27.47±4.91 pg/ml) bred
