Reproduction and milk production are considered to be the main factors influencing the whole economy of cattle breeding. We have been monitoring the worsening reproduction related to cattle breeding for a long time. The introduction of synchronization protocols into reproductive management is a posibility to improve reproduction. The aim of my work was to detect the success rate of insemination after rut synchronization on the basis of the data analysis and to evaluate reproductive indicators. The monitoring was performed from January 2017 to June 2018. There were monitored 310 breeding Holstein cows with the yield level of 10 335 kg of milk. The data were obtained from the zootechnical records and the Farmsoft Program. The breeding reproductive level was poor. Here are following values of reproductive indicators: insemination interval - 63 days, service period - 124 days, intervening time - 407 days, intersemination interval - 35 days, insemination index - 2,63 and pregnancy after the first insemination - 33,23%. That was only the insemination interval to achieve great results because breeding cows were involved into the synchronization protocol Presynch within 31 to 38 days after birth. It was detected that cows after the synchornization program Presynch got pregnant in 36,6% after the first insemination, whereas breeding cows being inseminated for the required rut became pregnant in 28% cases after the first insemination. The percentage of pregnancy in synchronizated cows after the first insemination is almost identical to the average in the Czech Republic (37,1%). Performing hormonal therapy within Presynch increased the reproductive costs in one cow by 211 Czech crowns.

Master of Science / Department of Animal Sciences and Industry / Jeffrey S. Stevenson / Lactating dairy cows from 2 Kansas farms were used to determine the effectiveness of exogenous progesterone in the form of an intravaginal insert (controlled internal drug release; CIDR) in conjunction with an ovulation-synchronization protocol. Cows were enrolled in a Presynch + Ovsynch protocol after parturition, where they received 2 injections of PGF[subscript]2[alpha], 14 d apart (Presynch) beginning between 30 and 36 DIM. Cows (n = 155) detected in estrus after the second PGF[subscript]2[alpha] injection of Presynch were inseminated (early AI). Remaining cows were assigned randomly to be treated with the Cosynch-72 protocol (GnRH 12 d after last Presynch PGF[subscript]2[alpha] injection, PGF[subscript]2[alpha] 7 d after GnRH, and timed AI + GnRH injection 72 h later) and served as controls (n = 159), or to be treated with the Cosynch-72 protocol and receive a progesterone insert (Ovsynch + CIDR; n = 175) for 7 d between GnRH and PGF[subscript]2[alpha]. Blood was collected at d −22 and −10 (relative to TAI at d 0) to determine cycling status based on progesterone concentrations and again at d 11 post AI to determine luteal competency. Treated cows were assigned body condition scores (BCS) on d −22 and −10. Pregnancy status was confirmed by palpation of the uterus per rectum and its contents on d 38 post-timed AI and verified again 4 wk later. Treatment with the progesterone insert increased timed AI pregnancies per AI in Cosynch- 72 + CIDR-treated cows when compared with controls (38 vs. 24%), but did not differ from early AI cows (38%). Pregnancy loss was numerically less in progesterone-treated cows than in controls (4.4 vs. 11.8%). Our study shows that increased pregnancies per AI can be achieved by the use of a progesterone insert in a reduced population of cows not yet inseminated, but treated with a progesterone insert.