No abstract

Sperm cryopreservation is an important method of assisted reproductive techniques and storing genetic resources. It plays a vital role in genetic improvement, livestock industrial preservation of endangered species, and clinical practice. Consequently, the cryopreservation technique is well organized through various studies, especially on Korean native cattle (Hanwoo). However, the cryopreservation technique of Korean native brindled cattle, which is one of the native cattle species in Korea, is not well organized. Therefore, it is necessary to develop a Supplementary Table technique for the cryopreservation of Korean native brindled cattle. For this purpose, it is important to first evaluate the quality of the currently produced cryopreserved sperm of Korean native brindled cattle. In this study, we randomly selected 72 individual Korean native brindled cattle semen samples collected from 8 different region research centers and used them to evaluate sperm functions. We focused on the quality evaluation of cryopreserved Korean native brindled cattle semen following the measurement of motion kinematics, capacitation status, intracellular ATP level, sperm motility, and cell viability. Then, the values of each of the eight groups were derived from various sperm parameters of nine individual samples, including sperm motility, kinematics, cellular motility, and intracellular ATP levels, which were used to compare and evaluate sperm function. Overall, differences in various sperm parameters were observed between most of the research centers. Particularly, the deviations of motility and motion kinematics were high according to the sample. Therefore, we suggest that it is necessary to develop a standard method for the cryopreservation of Korean native brindled cattle semen. We also suggest the need for sperm quality evaluation of the cryopreserved semen of Korean native brindled cattle before using artificial insemination to attain a high fertility rate.

How do body temperature and activity change before and after parturition in pregnant cows? Changes in body temperature such as ruminal, rectal, and vaginal temperature during the parturition have been reported, but there are no results of the simultaneous observation of body temperature and activity. The aim of this study was to simultaneously confirm changes in the ruminoreticular temperature and body activity before and after parturition using the ruminoreticular bio-capsule sensor every 1 h. The 55 pregnant cows were used for the experiment, the ruminoreticular bio-capsule sensor was inserted and stabilized, and the ruminoreticular temperature and body activity were measured. The ruminoreticular temperature was lower by 0.5° from −24 h to −3 h in parturition compared to 48 h before parturition and then recovered again after parturition. Body activity increased temporarily at the time of parturition and 12 h after parturition. Therefore, the ruminoreticular temperature and body activity before and after parturition was simultaneously confirmed in pregnant cows.

Background: With unique genetic traits, Hanwoo cattle (Bos taurus coreanae) are welladapted to the Korean environment. However, their perinatal mortality rate is 2%-3%, which imposes an economic burden.Objective: Due to insufficient data on hormonal changes around parturition, the timing of parturition is often predicted subjectively; few studies have examined hormones in Hanwoo cattle. We measured the changes in various hormones around parturition, to seek an objective predictor of parturition time. Methods:In 14 female Hanwoo cattle, we measured progesterone, prolactin and cortisol concentrations daily in jugular vein blood samples, beginning 6 days before parturition until 7 days after parturition. Conception was induced in five animals using artificial insemination. Nine animals received embryo transfer.Results: During parturition, the concentration of progesterone decreased significantly in the embryo transfer group (n = 9) and in the total population (n = 14); it did not change significantly in the artificial insemination group (n = 5). Prolactin concentration increased on the day of parturition but did not differ significantly among the groups.Cortisol remained constant throughout the study course. Conclusion:We concluded that parturition time can be predicted in Hanwoo cattle using progesterone concentration. This knowledge can reduce perinatal mortality, which would help to improve farm income and animal welfare.

Background: In Korean cattle, after foot-and-mouth disease (FMD) vaccination, anovulation increases, acute immune response is stimulated.Objective: Here, we aimed to improve the fertility rate by ovulation delay caused by the foot-and-mouth disease vaccine.Methods: 160 cows (control, FMD, FMD+Gn250 and FMD+Gn500 groups, with 40 cows each) were used. We analysed the ovulation delay, ovulation rate, conception rate and acute-phase immune responses. Results:In the group vaccinated only with FMD, the average follicle size was maintained at 12 mm and ovulation was delayed. The ovulation rate of the FMD+Gn500 group (500 μg gonadotropin-releasing hormone (GnRH) injections 3 days after the FMD vaccination) was the highest at 81.8%. The ovulation rate of the FMD+Gn250 group (250 μg GnRH injections 3 days after FMD vaccination) was 54.5%, and that of the control group (not FMD vaccinated) was 53.3%. The conception rate was 52.5% (19/40) in the control group, 37.5% (15/40) in the FMD+Gn250 group, and 67.5% (27/40) in the FMD+Gn500 group. Analysis of acute-phase immune response revealed that the plasma contents of haptoglobin and serum amyloid A increased up to 7 days after vaccination against FMD in all the experimental groups, except the control group. Conclusions:We concluded that ovulation delay can be employed to improve conception rate after FMD vaccination through a modified ovulation synchronisation method with GnRH. K E Y W O R D Sconception rate, foot-and-mouth disease vaccine, gonadotropin-releasing hormone, Hanwoo (Bos taurus coreanae) cow, ovulation delay Daehyun Kim and Woo-Sung Kwon contributed equally to this work.