Abstract:
The objectives of this study were to identify cows with follicular cysts and study the efficacy of CIDR (Progesterone=1.9g) treatment against ovarian follicular cysts in Japanese Black and Hoistein cows. Forty-one cows from Kagoshima Prefecture and Miyazaki Prefecture were initially identified by rectal palpation to have follicular cysts. These were randomly allocated into three groups where group 1 (n=29) were treated with CIDR for 7 days, group 2 (n=11) treated with CIDR for 14 days, and group 3 (n=1) as the control group where no CIDR was inserted. After removal of CIDR, all animals received an intramuscular injection of 25 mg PGF_<2α>. Fifteen out of 41 cows were confirmed to have follicular cysts after plasma progesterone determination by radioimmunoassay, as they had a pre-treatment progesterone concentration of<1ng/ml. Four Holstein cows were treated with 7 days of insertion. The plasma progesterone concentration increased significantly (P<0.01) after CIDR treatment i. e. day 0 (0.32±0.22ng/ml) to day 21 (3.96±1.99ng/ml). Eight Japanese Black cows with a pre-treatment mean plasma progesterone concentration of 0.32±0.26ng/ml were treated with CIDR for 7 days where 7 of them (87.5%) had an increased post-treatment progesterone concentration of 3.66±1.54ng/ml (P<0.01). Three Japanese Black cows treated with 14 days of CIDR insertion had pre-treatment and post-treatment progesterone concentrations of 0.35±0.14ng/ml and 2.40±1.86ng/ml, respectively (P=0.09). Fourteen out of fifteen ovarian follicular cyst cases had increased progesterone levels 14 days after CIDR removal (post-treatment period), 11 cows (73.3%) came to estrus 2-6 days after removal of the CIDR device and ovulation of a dominant follicle occurred with following formation of the corpus luteum. The overall success rate of CIDR treatment against ovarian follicular cysts (increase in plasma progesterone concentration>1ng/ml) was 93.3% in both treated groups.
