• Korean Journal of Veterinary Research
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• v.18 no.2
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• pp.69-71
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• 1978

Thirty heads of healthy pregnant and six heads of nonpregnant Holstein Friesian cows were selected for the purpose of serum chemical analysis. The partitions studied include serum total protein and total lipid with gestation periods (2.4.6.8. and 10 Months). The results were summarized as follows: 1. The mean value of serum total protein in 2 months of pregnant group was $7.70{\pm}0.28$ (7.4~8.3) g/100ml and then showed a tendency of decrease with the progress of pregnancy, that of 10 months group was figured $7.32{\pm}0.28$ (6.9~7.8) g/100ml. 2. The mean value of serum total lipids in 2 months of pregnant group was $335.67{\pm}14.69$ (300~386) mg/100ml and then showed a tendency of increase with the progress of pregnancy, that of 10 months group was figured $399.00{\pm}11.48$ (386~443) mg/100ml.

• Biomedical Science Letters
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• v.9 no.1
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• pp.29-36
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• 2003

Progesterone levels in the blood plasma or skim milk of cows are considered to be very useful indicator fur the detection of estrus cycle and early pregnancy diagnosis. During 13 to 14 days after estrus the level of progesterone in plasma or skim milk were not different between the inseminated arid non-inseminated cows. In the pregnant cows the peak level of progesterone reached on 14th day after artificial insemination (AI), but in the absence of conceptus the level declines after the 14th day slowly, and then very rapidly towards the basal level after the 17th day. This low level persists about 4 days, including those of estrus and ovulation a highly characteristic pattern which differs so markedly from that in the pregnant cows. Progesterone levels in blood plasma or skim milk can provided a reliable diagnosis of early pregnancy and monitoring ovarian activity in cows. The mean $\pm$ standard deviation of milk urea nitrogen(MUN) and protein concentration in the cows at 9 herds were 17.7$\pm$2.35 mg/dL and 3.2$\pm$0.17%, respectively. The days of nonpregnant after parturition was shorter in the cows in which the lower level of MUN than higher level of MUN concentration.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.133-143
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• 2006

Diagnosis on reproductive failures of dairy cows by ultrasonography was performed for 151 dairy cows. To diagnose types of reproductive failures, ultrasonography (SA 600, Medison, 5.0 MHz rectal linear transducer) was carried out in combination with rectal examination. Of 151 dairy cows, pregnant cows were 13 and the cows in normal estrual cycle were 40 cows, thereby the cows with reproductive failures were 98 cows. 1. Of 98 cows with reproductive failures, the cows with ovarian diseases were 34 cows (34.7%) and the cows with uterine diseases were 41 cows (41.8%). 2. The diameter of follicle in proestrus was 1.94 cm and it was longer than that of follicle in diestrus (p<0.05). 3. The mean size of corpus luteum of pregnant cows was bigger than that of corpus luteum in normal diestrus (p<0.05). 4. The length of cystic corpus luteum was 3.26 and the width of that was 1.91 cm. The length of corpus luteum tissue was 1.95 and the width of that was 1.91 cm excluding the size of cavity in corpus luteum. 5. The mean length of follicular cyst was 3.31 and the mean width of that was 2.3 cm. 6. The mean length and width of luteal cyst was 3.45 and 2.25 cm, respectively. The mean length and width of corpus luteum tissue was 1.15 and 0.67 cm, respectively, excluding the size of cyst in the luteal cyst. 7. The width of uterine horn associated with endometritis was significantly reduced as the period after parturition was elapsed (p<0.05). The mean width of uterine horn within 40 days after parturition was 4.55 cm. These results indicated that ultrasonography is of great use for accurate diagnosis both on ovarian diseases and uterine diseases and that it is very effective to diagnose endometritis in dairy cows.

• Journal of Embryo Transfer
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• v.22 no.2
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• pp.115-119
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• 2007

This study was carried out to investigate the effects of hormones (progesterone, and combination of progesterone and estradiol) on the reproductive performance of dairy cattle. The intravaginal CIDR was inserted in the vagina of cow on day 14 post-insemination to stimulate progesterone secretion with and without estradiol. The CIDR was removed on the day of next expected estrus. The cows for control group were not treated with CIDR or hormones. Conception rate, estrus interval, estrus intensity and serum progesterone were measured. Conception rates in control, CIDR without estradiol and CIDR treated cows were 15.4, 38.9 and 60%, respectively. Estrus interval in cows treated with CIDR was 26.5 days compared with 37.1 and 48.5 days in control and CIDR without estradiol treated cows. Estrus signs were more intense in cows treated with CIDR compared with control and CIDR without estradiol treated cows. Pregnant cows treated with CIDR showed higher serum progesterone concentration than pregnant and non-pregnant cows in control group. Particularly, serum progesterone was significantly higher in CIDR treated pregnant cows compared to non-pregnant cows at days 1, 2 and 6 of gestation. It may be concluded from present results that CIDR treatment is better than CIDR without estradiol to improve conception rate in dairy cattle.

• Proceedings of the KSAR Conference
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• 2001.03a
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• pp.73-73
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• 2001

This study was to examine whether the vitrified, one-step diluted and direct transferred Hanwoo IVM/IVF/IVC blastocysts can be successfully survived in vivo and they were succeeded into the live birth. For vitrification, blastocysts were serially exposed in glycerol (G) or/and ethylene glycol (EG) mixtures [10% (v/v) G for 5 min, 10% G plus 20% EG (v/v) for 5 min, and 25% G plus 25% EG (v/v) for 30 sect] which is diluted in 10% FBS added D-PBS. Thawing of straw was carried out in air for 10 sec and then in water bath of $25^{\circ}C$ for 20 sec. One-step dilution within the straw was done in water bath of $25^{\circ}C$ for 1 min. Vitrified and one-step diluted embryos were directly transferred into 36 (natural or hormone induced synchronized) recipient cows in 6 areas of Kyungsang Buk-Do. Pregnancies were confirmed at first when recipient cows did not return to the subsequent estrus cycle, and later by manual palpation per rectum on day 45, 90 and then living calves were derived into parturition. Overall pregnancy was 33.3%(12/36), However, higher pregnancy was obtained when the recipients exhibited estrus one day earlier than the age of transferred embryos (53.3 vs 25.0-27.3%), irrespective of synchronization methods. Also, parous recipients became pregnant higher than nulliparous heifers, And, there were not different in pregnancy rates by the aspect of corpus luteum (CL) quality of recipients (good, 29.4; fair, 37.5; poor, 33.3%). One hundred eight of frozen-thawed Hanwoo blastocysts were directly transferred into 36 recipient cows. In 12 of pregnant cows, 3 cows were aborted and 9 cows were calved [single, 66.7% (6/9): twin, 33.3% (3/9)]. Total embryo implantation rate was 11.1% (12/108). However, 9 Hanwoo calves were lived. Therefore, these results demonstrate that direct transfer technique of vitrified and one-step diluted bovine blastocysts can be applied easily and effectively with the higher pregnancy rate on field trial without the equipment and embryological skills.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.11
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• pp.1828-1832
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• 2018

Objective: Environmental change is one of the stressful events in livestock production. Change in environment disturbs cow behavior and cows require several days to regain a stable behavioral pattern. Sleeping posture (SP) and lying posture (LP) have been used as indicators for animal that are relaxed and well-acclimated to their environment. The aim of this study was to examine the time required by Japanese black cows for stabilization of SP and LP after moving into new environment. Methods: Seven pregnant Japanese black cows were used. Cows were moved into new tie-stall shed and their sleeping and lying posture measured 17 times during 35 experimental days. Both SP and LP were detected by accelerometer fixed on middle occipital and hip-cross, respectively. Daily total time, frequency, and average bout of both SP and LP were calculated. Results: Daily SP time was the shortest on day 1 and increased to the highest on day 3. It then decreased until day 9, after that stabilized about 65 min/d till the end of experiment. Daily LP time changed in same manner as daily SP time. The average SP bout was the longest on day 1, and then decreased to stable level on day 7. On the other hand, the average LP bout was the shortest on day 1, and it increased to stable level on day 7. Conclusion: These results showed that pregnant Japanese black cows needed 1 week to stabilize their SP. However, there were different change patterns between the average SP and LP bout, even though the change pattern of daily SP and LP time were similar.

• Journal of Embryo Transfer
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• v.12 no.1
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• pp.75-90
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• 1997

This study was carried out to establish the techniques for producing the calves of genetically superior Korean Native cattle by transfer of frozen-thawed embryos. The effects of some factors related to embryo recovery following superovulation and pregnancy rate following transfer of frozen-thawed embryos were evaluated. Also calving state was investigated. The results obtained were as follows ; The mean number of total and transferrable embryos recovered per superovulated cow was 8.72 and 4.90, respectively, from a total of 72 superovulations using 34 donor cows. There were no significant differences in the number of total or transferrable embryos recovered per superovulated cow between products of follicle stimulating hormone (FSH), years, seasons, and collection numbers. The pregnancy rate was found 44.44% following transfer of frozen-thawed embryos of Korean Native cattle to a total of 180 recipient cows including 82 Angus, 27 Charolais, 62 Hereford and 9 Korean Native cows. The pregnancy rate was significantly (P<0.05) higher in the transfer of excellent (42.99) and good embryos (40.17%), compared with fair (5.90%) grade embryos. And the pregnancy rate was significantly (P<0.05) higher in the transfer of embryos of morula stage (43.86%) than blastocyst stage (15.51%). But there were no significant differences in pregnancy rates between natural and induced estrus estrus asynchrony of 1 days, breeds, and parities of recipient cows. The normal calving rate of 80 pregnant cows following transfer of frozen4hawed em-bryos was 87.5% and the other 10 pregnant cows showed abortion during the period from pregnancy diagnosis at 50~60 days to calving. The average gestation length of normally delivered recipients was 288.50 days and the average birth weight of 70 calves born was 24.22 kg. The gestation length was significantly (P<0.05) shorter in the recipients delivering female calves (286.70 days) than males (289.39 days). But there were no significant differences in gestation tength and birth weight of calves born between the recipient breeds.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1254-1260
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• 2003

The purpose of this study firstly was conducted to establish a radioimmunoassay (RIA) of estrone sulfate ($E_1S$), secondly to monitor the reproductive status of dairy cows using their urine samples. Urine and blood samples were collected in series within a day from four pregnant Holstein-friesian cows to evaluate the relationship between $E_1S$ levels in blood and urine with or without urinary creatinine basis. The urine was then collected biweekly from three cows in estrous and those artificially inseminated; collection from pregnant cows was made on a monthly basis. Results indicated that sensitivity for the $E_1S$ RIA was 5 pg/tube and the recovery rate was 100%. The daily urinary creatinine concentrations fluctuated within a day, but changes were slighter in midday, whereas the changes of concentrations of $E_1S$ in urine were relatively smaller. The concentrations of serum $E_1S$ during the estrous cycle were undetectable due to the limitation of assay, but the urinary $E_1S$ level could be measured with no obvious changes during the cycle. The urinary $E_1S$ levels increased remarkably around 7.7 to 8.3 ng/ml, 80 to 100 days after pregnancy but the serum $E_1S$ levels did not elevate until 120 to 150 days. The level of $E_1S$ increased gradually during pregnancy and eventually reached its peak before parturition at around 40 ng/ml and finally decreased to its basal level 2 days postparturition. During pregnancy, $E_1S$ concentrations of urine increased earlier than those in blood. The correlation coefficients between urinary and serum $E_1S$ concentration during pregnancy and postparturm were higher than those adjusted with creatinine (creatinine ratio). The concentrations of $E_1S$ in urine could be maintained unchanged for 8 days storing the samples in room temperature, which was extended to 8 days when the samples were pretreated by boiling for 30 minutes or treated with autoclave. In conclusion urinary $E_1S$ concentrations can be used directly for monitoring the pregnant status and fetal viability of dairy cows and can assist accurate confirmation of pregnancy in cows at least 80 to 100 days after insemination much earlier than by serum $E_1S$.

• Asian-Australasian Journal of Animal Sciences
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• v.30 no.3
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• pp.347-354
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• 2017

Objective: The effects of the pre- and postpartum supplementation of cows with Se on their plasma P4 concentrations after calving were investigated. Methods: Thirty-four Holstein cows were used to investigate the effects of dietary selenium supplementation on the postpartum recovery of the luteal function in cows. Selenium-rich yeast (containing 300 ppm selenium) was mixed with total mixed ration fed to 17 pregnant cows from 30 days before they were due to calve (10 g yeast daily) to 100 days after calving (20 g yeast daily). The control cows (n = 17) were fed the same amount of ordinary yeast. The cows' plasma progesterone concentrations were determined every two days using an enzyme immunoassay after calving. Results: Feed intake (total digestive nutrient, crude protein), milk production, body weight and the biochemical properties of blood plasma did not differ between the two groups; however, the plasma selenium concentrations of the supplemented animals were significantly greater than those of the controls at and after calving. The postpartum plasma progesterone concentrations of the selenium-yeast-supplemented group increased earlier than those of the control group. Moreover, during the estrus cycle after the 3rd ovulation or ovulation with estrus between 60 to 80 days after calving, the selenium-supplemented cows exhibited greater progesterone concentrations than the control cows. Conclusion: Selenium supplementation promotes the postpartum progesterone production of cows.

• Journal of Animal Science and Technology
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• v.63 no.6
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• pp.1265-1274
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• 2021

Two field experiments were conducted to improve the conception rate of Hanwoo cow. The first experiment aimed to investigate the physiological condition of Hanwoo cows on estrus, including metabolic profiles and body condition score (BCS). The second experiment investigated the effect of a novel estrus detector on the artificial insemination (AI) conception rate for Hanwoo cows. For the first experiment, 80 Hanwoo cows (2.5 ± 0.10 of parity), approximately one month before estrus, were housed in 16 pens and offered the experimental diets twice daily with free water access. The BCS were recorded, and blood was collected from the jugular veins just before AI. The collected blood was used to measure physiological conditions, such as metabolite and hormone levels. For the second experiment, each cow was equipped with a neck-mounted estrus detector collar, which had a sensor connected through the internet. Approximately one month before estrus, three hundred sixty Hanwoo cows (2.4 ± 0.21 of parity) were assigned into groups with or without W-Tag collar treatments. The animals were managed the same as in the first experiment. The pregnancy rate reached 55% in the first experiment. The concentration of luteinizing hormone (LH) was higher (p < 0.012; 1.56 vs. 1.08 ng/mL) in cows that were not pregnant (NPG) than in cows that were pregnant (PG) after AI. The BCS and other concentrations of metabolites and hormones in the blood were not different in both NPG and PG cows. The ranges of estrogen, LH, and follicle-stimulating hormone for PG cows were 11.9 to 39.0 pg/mL, < 0.25 to 1.98 ng/mL, and < 0.50 to 0.82 ng/mL, respectively. In the second experiment, cows with the estrus detector had lower days open (p < 0.001; 78.1 vs. 84.8 d), insemination frequency (p < 0.001; 1.26 vs. 2.52), and return of estrus (p < 0.001; 70.9 vs. 79.1 d) than those in cows without the estrus detector. In conclusion, the present study indicated that lower LH concentration just before AI potentially increased the pregnancy rate of Hanwoo cows. Furthermore, the application of estrus detectors to Hanwoo cows could improve the conception success rate for AI.