Tiaprost (Iliren)

Luteolysis in cows using the prostaglandin F2 alpha analogue, tiaprost, and the effect of mode of administration

Thirteen cows received 0.75 mg tiaprost by subcutaneous injection during the mid-luteal phase of the ovarian cycle. Twelve underwent rapid luteolytic and continued to cycle normally as determined by milk or plasma progesterone concentrations. The other cow underwent only a transient decrease in progesterone concentrations. A further 15 cows received either a subcutaneous osmotic mini-pump containing 30 mg tiaprost , calibrated to release 0.75 mg over a 24 hour period (group 1); a subcutaneous injection of 0.375 mg tiaprost (group 2), or a subcutaneous injection of 0.375 mg tiaprost plus the osmotic mini pump (group 3). Treatment caused luteolysis in zero and one cows in groups 1 and 3 respectively. However all six cows in group 2 underwent rapid luteolysis. Although the standard therapeutic dose of tiaprost (0.75 mg) appears to be a highly effective luteolytic agent it is concluded that there may be scope for development of longer acting formulations of this compound.

Endometritis treatment with a PGF2alpha analog does not improve reproductive performance in a large dairy herd in Argentina

In Argentina, most dairy cows with endometritis are treated with prostaglandin (PGF(2alpha) or its analogs) and insemination is withheld until there are no signs of endometritis. The objective of the present study was to evaluate if this method of managing endometritis enhances reproductive performance. Three experiments were conducted over 4 years in a large farm in the west of Buenos Aires province. In Experiment 1, half of the cows diagnosed with endometritis (>1.5-fold difference in diameter of uterine horns, as determined by rectal palpation) received standard endometritis management (treatment with tiaprost, a PGF(2alpha) analog, rectal palpation every 20 days, and withholding of AI until endometritis apparently resolved) and the other half was untreated, with AI at the first estrus after the voluntary waiting period. Untreated cows were inseminated and conceived 20 days earlier than treated cows, and the pregnancy rate by Day 90 postpartum was higher in the untreated group. In Experiment 2, cows with endometritis were divided into four groups according to the severity of symptoms; within each group, cows were allocated to treatment or control, as in Experiment 1. Although first service conception rate decreased as endometritis severity increased, reproductive performance in treated versus control cows was similar to that of Experiment 1 (with no interaction due to degree of endometritis). Re-evaluation of the treated cow (to confirm uterine "normality") may have been responsible for the delay in conception in both experiments. The objective of Experiment 3 was to determine the effects of tiaprost treatment on clinically normal postpartum cows (no evidence of endometritis). Tiaprost treatment reduced the interval from calving to conception in multiparous cows, but it delayed conception and reduced the conception rate in primiparous cows. In conclusion, treatment with tiaprost impaired reproductive performance in primiparous cows (in the absence of endometritis). Furthermore, the standard treatment for endometritis (treatment with a prostaglandin analog and withholding insemination until clinical signs abated) impaired reproductive performance and increased costs.

Fertility responses and hormonal profiles in repeat breeding cows treated with insulin

The influence of insulin treatment on conception rate and endocrine profile was studied on 21 repeat breeding cows divided randomly into two groups, i.e. insulin treatment (n = 11) and control (n = 10). Cows of the insulin treatment group were injected subcutaneously with a long acting purified form of bovine insulin at 0.2 IU/kg body weight/day on days 8, 9 and 10, and then with 0.75 mg tiaprost (PGF(2)alpha) intramuscularly on day 12 of the oestrous cycle (oestrus = day 0). The cows of the control group only received 0.75 mg tiaprost was injected intramuscularly on day 12. There was no difference (P > 0.05) in the interval to the onset of oestrus and subsequent cycle length between the treatment (84.5 +/- 6.6 h and 21.2 +/- 0.6 days, respectively) and the control (72.3 +/- 5.9 h and 19.7 +/- 0.4 days, respectively) groups. First service conception rate and overall pregnancy rate did not differ (P > 0.05) between the insulin treatment group (45.4 and 63.6%) and the control group (33.3 and 40.0%). Progesterone concentration following administration of insulin increased (P < 0.05) in the insulin treated cows (2.2+/-0.4 ng/ml versus 2.9 +/- 0.4 ng/ml) but the concentration of oestradiol-17beta did not differ. The insulin concentration was higher on day 10 of the oestrous cycle (P < 0.05) in the treatment group (71.0 +/- 12.5 microU/ml versus 38.1 +/- 4.5 microU/ml). The insulin and glucose concentrations were higher (P > 0.05) in animals, which subsequently became pregnant than in non-pregnant animals. The results may indicate that there is beneficial effect of insulin on fertility in repeat breeder cattle.

Timing of ovulation and conception rate in primiparous and multiparous cows after synchronization of ovulation with GnRH and PGF2alpha

Conception rates after Ovsynch have been higher in primiparous than in multiparous cows. The objective of this study was to investigate whether this difference might be due to differences in ovulation rate or follicular size. The experiment was conducted with 136 Holstein Frisian cows from a commercial herd in Brandenburg, Germany. All cows were synchronized using Buserelin (GnRH analogue) at day -10, Tiaprost (PGF2alpha analogue) at day -3 and again GnRH at day -1. Timed artificial insemination (TAI) was carried out 16-20 h after the second dose of GnRH on day 0. Milk samples for analysis of milk progesterone were obtained on days -17, -10, -3 and at TAI. Progesterone concentrations were used to determine the stage of oestrus cycle at the start of the synchronization protocol and to investigate the presence of functional luteal tissue before treatment with PGF2alpha and TAI. All animals were examined by ultrasound at the second treatment with GnRH, at AI, 8 and 24 h after AI. Overall synchronization rate (proportion of cows with an ovulation within 40 h after GnRH) was 86.8% in primiparous and 88.2% in multiparous cows, respectively. Ovulation occurred earlier in primparous than in multiparous cows (p < 0.05) and ovulatory follicles were smaller. Conception rates were numerically higher in primiparous cows but the difference was not significant. Cows that displayed signs of oestrus on day -1 and received an additional AI on this day were more likely to conceive than cows that only received TAI 16 to 20 h after GnRH2. It is concluded that ovulation occurs earlier in primiparous than in multiparous cows after Ovsynch. However, a significant relationship between these differences and the probability of conception could not be established.

Delayed termination of third-trimester gestations in dairy cows after treatment with the PGF(2alpha)analog Tiaprost

Six dairy cows of the German Black Pied breed were treated between days 190 and 266 of gestation with 0.75 mg of the PGF(2alpha) analog Tiaprost (Iliren(R)-Hoechst). Luteolysis occurred within 24 hours, with progesterone blood levels dropping to baseline values of about 3.18 nmol/l (l ng/ml), but pregnancies were terminated by spontaneous abortions or premature parturitions only after an average of 24.2 days (range 5 to 50 days) after treatments. Four of six deliveries were premature and all deliveries were preceded by a rise in blood estrogen levels which commenced 1 to 12 days prepartum and peaked intrapartum. Unsuccessful attempts were made to induce this estrogen rise earlier by using treatments with Tiaprost, PGF(2alpha)-THAM or estradiol benzoate; treatments with a progesterone-releasing intravaginal device did not prevent the estrogen rise. Abortions and parturitions were spontaneous or by slight pulling. The placenta was retained in all six animals. Two immature fetuses were stillborn, and one immature born calf died three hours after birth.