Presynchronization of estrous cycles in dairy cows before ovsynch + CIDR and resynchronization of repeat estrus using the CIDR

Postpartum anestrus is one of the major limitations to achieving acceptable pregnancy rates. The Ovsynch protocol is an excellent tool to improve reproductive efficiency of dairy cows because it can induce estrous cycles in anestrous cows. In the first experiment, administering two PGF2 injections to lactating dairy cows 14 days apart with the second injection given 12 days before the Ovsynch protocol increased (P\u3c0.05) pregnancy rate by 10 percentage points in cycling and noncycling cows. Inserting a progesterone-releasing insert (CIDR) for 7 days during the Ovsynch protocol did not further increase pregnancy rates. In a second experiment, a resynchronization treatment consisting of a used CIDR inserted for 7 days from days 13 to 20 after insemination increased (P\u3c0.05) embryo survival from day 30 to 58 by 11 percentage points but failed to increase overall rate of return to estrus and conception rate at the second AI (first eligible estrus after first AI).; Dairy Day, 2001, Kansas State University, Manhattan, KS, 2001

Fixed-time inseminaton of suckled beef cows. 2. Cosynch and progesterone

The Cosynch protocol (GnRH 7 days before and again 48 h after PGF2 with AI at the second GnRH injection) produced pregnancy rates in suckled beef cows that exceeded 50% without heat detection and with only three handlings of all cows. The addition of an intravaginal progesterone insert to the Cosynch protocol improved pregnancy rates in two of the three breeds of cows studied

Presynchronization of estrous cycles in dairy cows before ovsynch + CIDR and resynchronization of repeat estrus using the CIDR

Postpartum anestrus is one of the major limitations to achieving acceptable pregnancy rates. The Ovsynch protocol is an excellent tool to improve reproductive efficiency of dairy cows because it can induce estrous cycles in anestrous cows. In the first experiment, administering two PGF2 injections to lactating dairy cows 14 days apart with the second injection given 12 days before the Ovsynch protocol increased (P\u3c0.05) pregnancy rate by 10 percentage points in cycling and noncycling cows. Inserting a progesterone-releasing insert (CIDR) for 7 days during the Ovsynch protocol did not further increase pregnancy rates. In a second experiment, a resynchronization treatment consisting of a used CIDR inserted for 7 days from days 13 to 20 after insemination increased (P\u3c0.05) embryo survival from day 30 to 58 by 11 percentage points but failed to increase overall rate of return to estrus and conception rate at the second AI (first eligible estrus after first AI).; Dairy Day, 2001, Kansas State University, Manhattan, KS, 2001

Anestrus in lactating dairy cows before ovulation synchronization

The incidence of anestrus in dairy cattle prior to first inseminations carried out after a minimum of 60 days postpartum ranged from 4 to 58% in first-lactation cows and 14 to 50% in older cows. Dairy cows with more days in milk, older than 2 years, and in better body condition (probably reflective of greater postpartum dry matter intakes) were more likely to cycle than thinner cows. Cows that were not cycling before the first week of insemination conceived at lower rates and took longer to become pregnant

Fixed-time inseminaton of suckled beef cows. 2. Cosynch and progesterone

The Cosynch protocol (GnRH 7 days before and again 48 h after PGF2" with AI at the second GnRH injection) produced pregnancy rates in suckled beef cows that exceeded 50% without heat detection and with only three handlings of all cows. The addition of an intravaginal progesterone insert to the Cosynch protocol improved pregnancy rates in two of the three breeds of cows studied

Presynchronization of estrous cycles in dairy cows before ovsynch + CIDR and resynchronization of repeat estrus using the CIDR

Postpartum anestrus is one of the major limitations to achieving acceptable pregnancy rates. The Ovsynch protocol is an excellent tool to improve reproductive efficiency of dairy cows because it can induce estrous cycles in anestrous cows. In the first experiment, administering two PGF2" injections to lactating dairy cows 14 days apart with the second injection given 12 days before the Ovsynch protocol increased (P<0.05) pregnancy rate by 10 percentage points in cycling and noncycling cows. Inserting a progesterone-releasing insert (CIDR) for 7 days during the Ovsynch protocol did not further increase pregnancy rates. In a second experiment, a resynchronization treatment consisting of a used CIDR inserted for 7 days from days 13 to 20 after insemination increased (P<0.05) embryo survival from day 30 to 58 by 11 percentage points but failed to increase overall rate of return to estrus and conception rate at the second AI (first eligible estrus after first AI)

Synchronizing estrus in replacement beef heifers using select synch, MGA, AND PGF2

The Select Synch protocol (GnRH at day - 7, PGF2 at day 0, AI at detected heat) was compared to protocols using either MGA + prostaglandin (Colorado system) or two injections of prostaglandin to synchronize estrus in replacement heifers at three locations. Percentage of heifers detected in heat before, during, or after the target breeding week was not different among treatments but varied in percentages among locations. Overall conception rates ranged from 64 to 69%. Pregnancy rates varied from 46 to 56% and tended to be greatest in the MGA + PGF2" treatment. Costs of these treatments ranged from $3.50 to$8 and were lowest for the MGA + PGF2 protocol

Supplemental progestin increases pregnancy rates in suckled beef cows

In two experiments, combining a source of progestin with the ovulation synchronization protocol using gonadotropin-releasing hormone plus prostaglandin F2a (GnRH + PGF2a) tended to increase or statistically increase pregnancy rates in suckled cows compared to GnRH + PGF2a alone. These improvements were accomplished without any detected estrus when cows were inseminated and received a second injection of GnRH at 48 hr after PGF2a