Voluntary waiting period and adoption of synchronized breeding (ovulation synchronization followed by timed artificial insemination) were characterized from 33 million services of Holsteins and Jerseys in Dairy Herd Improvement herds. Calving month, calving year, and parity had large effects on days to first service for both breeds. Holstein cows that calved during March and April were bred lat...

Dairy herd size is expected to increase in many European countries, given the recent policy changes within the European Union. Managing more cows may have implications for herd performance in the post-quota era. The objective of this study was to characterise spring-calving herds according to size and rate of expansion, and to determine trends in breeding policy, reproduction and production per...

The objective of this study was to evaluate effects of a daily oral drench of Propylene Glycol (PG) on fertility in dairy cows experiencing seasonal heat stress. In treatment group, cows (n=9) were treated with drenching 250 ml propylene glycol once daily from 3 to 15 days post-partum following the morning milking. Another group of cows (n=9) was selected as untreated control. The serum beta-hy...

Lactating dairy cows have unique reproductive responses compared to when they were heifers that result in distinctly different reproductive measurements and pregnancy outcomes that can be partially overcome with pharmacological strategies. These parameters include circulating progesterone and estradiol concentrations, ovulatory follicle and corpus luteum diameter, incidence of anovulation and d...

In the study, 6 donors (n=6) cow of Selenge (n=3) and Alatau breeds were selected for superovulation. Superovulation treatment artificial insemination (AI) Donor Cow Regardless estrous cycle, Insert Controlled Internal Drug Release (CIDR; Hamilton, New Zealand) to from 5th day after inserting CIDR, diminishing inject Follicle Stimulating Hormone (FSH; Kyoritsu Seiyaku Corporation, Japan.) 36IU ...

Our objective was to determine whether pregnancy rates in heat-stressed dairy cattle could be enhanced by timed embryo transfer of fresh (nonfrozen) or frozen-thawed in vitro-derived embryos compared to timed insemination. Ovulation in Holstein cows was synchronized by a GnRH injection followed 7 d later by PGF2 alpha and a second treatment with GnRH 48 h later. Control cows (n = 129) were inse...

The reproductive ability, milk-producing capacity, survival time and relationships of these parameters with telomere length were investigated in 4 groups of cows produced by somatic cell nuclear transfer (SCNT). Each group was produced using the same donor cells (6 Holstein (1H), 3 Holstein (2H), 4 Jersey (1J) and 5 Japanese Black (1B) cows). As controls, 47 Holstein cows produced by artificial...

The main objective was to determine the efficacy of using X-sorted sperm to produce embryos in vitro for transfer into lactating dairy cows. Cows were bred by timed artificial insemination (TAI) using nonsorted semen or X-sorted sperm, or they received a fresh embryo produced in vitro by fertilization with X-sorted or nonsorted sperm using timed embryo transfer (TET). Pregnancy rates at approxi...

Postpartum anestrous is one of the most important problems in the dairy industry in the world and especially in Iran. The objective of present study was to compare the efficacy of two hormonal programs for recycling of postpartum anestrous cows. For this reason, 230 Holstein cows from 4 similar dairy herds (with totally 2560 cow and unique management and feeding system) located on the suburb of...

Dairy farmers have been longing for simple and economical methods of early pregnancy diagnosis. Urine based biochemical and mineral assays could be one of those methods, owing to the ease of sample collection and relatively simple and economical assays involved. However, basic information on changes in urinary composition during early pregnancy in cattle is lacking. This study was designed to e...