Effect of increasing amounts of supplemental progesterone in a timed artificial insemination protocol on fertility of lactating dairy cows

Abstract

The objectives were to evaluate the effect of supplemental progesterone during a timed artificial insemination (TAI) protocol on pregnancy per insemination and pregnancy loss. Lactating dairy cows from 2 dairy herds were presynchronized with 2 injections of PGF(2alpha) 14 d apart, and cows observed in estrus following the second PGF(2alpha) injection were inseminated (n = 1,301). Cows not inseminated by 11 d after the end of the presynchronization were submitted to the TAI protocol (d 0 GnRH, d 7 PGF(2alpha), d 8 estradiol cypionate, and d 10 TAI). On the day of the GnRH of the TAI protocol (study d 0), cows were assigned randomly to receive no exogenous progesterone (control = 432), one controlled internal drug-release (CIDR) insert (CIDR1 = 440), or 2 CIDR inserts (CIDR2 = 440) containing 1.38 g of progesterone each from study d 0 to 7. Blood was sampled on study d 0 before insertion of CIDR for determination of progesterone concentration in plasma, and cows with concentration <1.0 ng/mL were classified as low progesterone (LP) and those with concentration > or =1.0 ng/mL were classified as high progesterone (HP). From a subgroup of 240 cows, blood was sampled on study d 3, 7, 17 and 24 and ovaries were examined by ultrasonography on study d 0 and 7. Pregnancy was diagnosed at 38 +/- 3 and 66 +/- 3 d after AI. Data were analyzed including only cows randomly assigned to treatments and excluding cows that were inseminated after the second PGF(2alpha) injection. The proportion of cows classified as HP at the beginning of the TAI protocol was similar among treatments, but differed between herds. Concentrations of progesterone in plasma during the TAI protocol increased linearly with number of CIDR used, and the increment was 0.9 ng/mL per CIDR. The proportion of cows with plasma progesterone > or =1.0 ng/mL on study d 17 was not affected by treatment, but a greater proportion of control than CIDR-treated cows had asynchronous estrous cycles following the TAI protocol. Treatment with CIDR inserts, however, did not affect pregnancy at 38 +/- 3 and 66 +/- 3 d after AI or pregnancy loss.

Synchronisation of ovulation for management of reproduction in dairy cows

“…Bisinotto et al (2013) observed that incorporating Bisinotto, Ribeiro and Santos 154 two CIDR inserts during the timed AI protocol for cows without CL increased concentrations in plasma to 2.65 ng/mL and restored fertility similar to that of cows in dioestrus when the timed AI was initiated. Similar findings had been observed by Lima et al (2009b) and Denicol et al (2012). Therefore, when supplemental progesterone has to be used in high-producing cows, it is suggested that benefits to P/AI will be greater when the resulting concentrations of progesterone in blood resemble those of cows in dioestrus and, in some cases, two intravaginal devices are needed to achieve such concentrations.…”

“…The fact that the incorporation of a single progesterone insert to timed AI programmes improved P/AI in cows that lack a CL at the first GnRH injection, but not to reestablish fertility to the same level as those in dioestrus is likely related to the amount of progesterone released. The CIDR releases ∼90 mg of progesterone/day, which increases plasma concentrations in high-producing lactating dairy cows by ∼0.8 to 1 ng/mL (Cerri et al, 2009b;Lima et al, 2009b). Bisinotto et al (2013) observed that incorporating Bisinotto, Ribeiro and Santos 154 two CIDR inserts during the timed AI protocol for cows without CL increased concentrations in plasma to 2.65 ng/mL and restored fertility similar to that of cows in dioestrus when the timed AI was initiated.…”

Economics of fertility in high-yielding dairy cows on confined TMR systems

“…With 30% and 35% OD and CR, respectively, combined programmes outperformed the TAI only programme with higher values at increased levels of OD. The study concluded that with a reasonable OD rates of 50% to 60% (Lima et al, 2009;Chebel and Santos, 2010), it would be recommendable to use OD only if the expected CR was greater than 30% (greater than the expected TAI CR). In agreement with previous findings (Giordano et al, 2011), that study also found that inseminating cows detected in oestrus before completion of a synchronisation protocol and expecting a low CR has a negative effect on the overall reproductive and economic performance.…”

Diseases that Affect the Reproductive Performance of Dairy Cattle

“…The proportion of cows that remain anovular by 60 days postpartum ranges from 20% to 40% and can be as high as 60% (Lima et al, 2009 ). The severity and duration of negative energy balance postpartum is a major factor that infl uences ovarian activity and resumption of cyclicity postpartum in dairy cows.…”