• Journal of Embryo Transfer
• /
• v.30 no.3
• /
• pp.189-193
• /
• 2015

Calculating break-even price of calf production is closely associated with reproductive efficiency. To determine the price, we need data from reproduction records including number of claves weaned, number of cows exposed for breeding, and annual cash coast per cow, and average weaning or market weight of claves sold and retained. Unfortunately, the data were not available in Korea native cow (Hanwoo). To evaluate the performance and the price, we collected calving interval from about 60,000 cows for last 10 years and estimated reproductive performance. Calving interval was increased 4.3% and pregnancy rate was decreased about 1.4~2.8% year-on-year. Increases in growth rates of number of cow and semen per calf supported the low reproductive performance. Finally, break-even price was calculated using estimated percent calf crop and demonstrated that growth rate of break-even price is larger than that of annual cash per cow, suggesting cow-calf profitability and financial efficiency in Korea native cow (Hanwoo) is getting worse.

• Journal of Veterinary Clinics
• /
• v.7 no.1
• /
• pp.415-418
• /
• 1990

To investigate the changes of adrenal gland associated with follicular cyst in Korean native cattle, adrenals ans ovaries were collected from 54 Korean native cattle at abbatoir. Adrenals were stained by H-E stain and they were examined under light microscope. Enlargement of adrenal cortex affecting fascicular and reticular zone appeared in cows associated with follicular cyst.

• Korean Journal of Veterinary Research
• /
• v.43 no.4
• /
• pp.667-675
• /
• 2003

The safety of Brucella abortus strain RB51(SRB51) was investigated in dairy cows and Korean native cattle of 4~7th month of gestation. From experimentally inoculated cattle, 18 of 25 (72.0%) dairy cows, and 3 of 10 (30.0%) Korean native cattle were aborted or delivered premature fetus. There were no significant differences in the incidence of abortion depending on the inoculation route (intramuscular and subcutaneous) and dosages ($1{\times}10^9$, $2.8{\times}10^9$, and $4.0{\times}10^9$ CFU). The antibodies to the SRB51 were measured by a dot blot enzyme-linked immunosorbent assay. The highest titers to SRB51 were detected between 5~7 weeks after inoculation and the specitic antibody could be detected up to 28 weeks after inoculation. The SRB51 was isolated from amnio-allantoic fluid, bronchial lymph node, mammary gland, and supramammary lymph node in 5 of 25 dairy cows during 4 weeks after either abortion or delivery. Although SRB51 was isolated from 4 of 24 aborted fetus or normally delivered calves at parturition time, it was not isolated during 4 weeks afterward. Eleven of twentyfive dairy cows showed the endometritis and/or necrosis until 6 weeks after delivery, no lesions were seen at 8 weeks after delivery and uterus from control dairy cows. The results of present study revealed that SRB51 might induce the clinical signs of brucellosis in the pregnant cattle at 4~7th month of gestation.

• Korean Journal of Animal Reproduction
• /
• v.17 no.1
• /
• pp.35-41
• /
• 1993

The study was conducted to investigate the effects on environmental factors on the reproductive performance of Korean native cattle based on the data from 13, 588 records which were surveyed from 1983 to 1992. The results obtained in this study are as follows; 1. Mean performaces of the reproductive traits were 510.2days for the age at 1st service, 525.0days for the age at 1st conception, 808.7 days for the age at 1st calving, 102.5 days for the days to 1st conception postpartum and 388.6 days of the calving inverval. The cows of Chunbuk province were tended to be bred and calved at younger age and showed shorter calving interval than those of other provinces. 2. The effect of birth year was significant for the reproductive performances, especially, in 1986~1987 when the cattle prices dropped sharply and reproductive performances were poor. 3. The times of 1st service and 1st conception of heifers calved in spring tended to be delayed. Days to 1st conception postpartum, calving interval and days to 1st service postpartum of cows calved in fall were shorter than other calving season's cows. 4. Days to 1st conception postpartum, calving interval and days to 1st service postpartum of cow's were shortened and gestation length was prolonged as the number of parity increases.

• Korean Journal of Veterinary Research
• /
• v.29 no.2
• /
• pp.75-81
• /
• 1989

The levels of the serum and colostral total protein and immunoglobulins of the Korean native cows immediately after parturition and colostrum-conferred passive immune status of the Korean native calves were studied, and the results obtained were summerized as follows: The mean total protein, total immunoglobulin, IgG, IgM, and IgA concentrations in sera of 10 Korean native cows immediately after parturition were $6.8{\pm}0.4g/dl$, $24.39{\pm}3.41mg/ml$, $19.49{\pm}2.70mg/ml$, $4.56{\pm}1.14mh/ml$, and $0.35{\pm}0.08mg/ml$ respectively. And the mean total protein, total immunoglobulin, IgG, IgM, and IgA concentrations in colostrum were $15.0{\pm}1.1g/dl$, $116.13{\pm}23.07mg/ml$, $101.51{\pm}22.59mg/ml$, $9.46{\pm}1.99mg/ml$, and $5.17{\pm}1.59mg/ml$ respectively. The mean concentrations of total protein and immunoglobulins in colostrum were 2.1 times to 14.8 times higher than those in serum. The mean concentrations of total protein, total immunoglobuln, IgG, IgM, and IgA in sera from 211 Korean native calves at 2 days old were $6.7{\pm}0.9g/dl$, $35.74{\pm}9.56mg/ml$, $29.06{\pm}8.07mg/ml$, $4.91{\pm}2.99mg/ml$, and $1,9{\pm}0.99mg/ml$ respectively. Although the calves had been suckled the dam's colostrum, each of calves was considerably various in levels of serum total protein and immunoglobulins and 16.1 percent of the calves were in a state of hypoglobulinemia.

• Reproductive and Developmental Biology
• /
• v.37 no.1
• /
• pp.23-27
• /
• 2013

This study was carried out to investigate the influence of artificial insemination (AI) failure in 1,619 Korean native cows at Gangwon East area, Korea. The average AI failure rate was 37.02% in the cows and the highest rate was 40.85% in Yangyang-city. Based on the parity in the cows, the AI failure rate was 49.14% and 29.91% in the first and fifth parity cows, respectively. Whereas cows until fifth parity were decreased in AI failure, cows with sixth or more parity showed an upturning AI failure trends with the increasing of parity number. AI failure rate incidence according to the rump fat thickness measured by ultrasound was 28.9% and 33.4% at 5 mm to 10 mm and over than 15 mm, respectively. There was a positive correlation (0.2186) between AI failure rate of mother and that of their offspring cows. That is, offspring of dams with high AI failure rate showed also higher AI failure than those of dams having lower AI failure rate. In conclusion, these results indicate that the AI failure rate was closely related to the rump fat thickness, parity number, and conception rate of mother cows. In addition, these results might strengthen the basis to improve the reproductive performance in Korean native cows.

• Korean Journal of Animal Reproduction
• /
• v.8 no.2
• /
• pp.87-91
• /
• 1984

This study was conducted to determine the optimum time and the insemination site of frozen in Cheju native cows, and 660 cows first service inseminated with rectovaginal methods by 3 skillful technicians as 3 districts near Cheju City and Sogwipo City areas obtained the following results. Optimum time for insemination was 16-20 hours after the onset of estrus and 80.6% of 67 conceived to first insemination. In the rectovaginal technique used widely at present conception rate for the palpation of ovaries showed 6.6% (index) higher than that of non-palpation. Conception rate of the insemination site; the intra-uterine horn, intra-uterus, just inside the cervix and depositing in mid-cervix were 62.5, 78.4, 74.6, and 80.9% respectively, however, there was no difference in conception rate between cervical and uterine deposition of forzon semen except for the intra-uterine horn.

• Journal of Embryo Transfer
• /
• v.12 no.2
• /
• pp.203-209
• /
• 1997

This study was carried out to compare the actual size(length and height) of ovaries, follicles and corpora lutea of Korean native cow with those on sonograms. We used 3 different probes(3.5 MHz abdominal probe, 6.5 MHz transvaginal probe and 5.0 MHz transrectal probe) and a calipher for measurements of ovaries, follicles and corpora lutea on sonograms and actual size. Under water immersion, 157 ovaries were scanned with 3 probes and measured in actual size and compared each other. The average height and width of ovaries of Korean native cows were 17.40$\pm$3.99 and 34.23$\pm$6.02mm, respectively. In comparison of height, length of ovaries and preovulation follicles, we found that image with a transvaginal probe was nearly the same as the actual size(p<0.01), but with an abdominal probe the image was appeared larger than the actual size. In measurement(diameter) of preovulation follicles the transvaginal probe was proven to be more accurate to the actual size than other probes and in corpus luteum measurement all probes were accurate. In the comparison of number of follicles by different size ranges, there was no statistical difference in the count of follicles over 10 mm in diameter between the transvaginal probe and naked eyes.

• Korean Journal of Animal Reproduction
• /
• v.13 no.1
• /
• pp.1-6
• /
• 1989

A field survey was conducted to obtain the data on reproductive performation of Korean native cattle. The data for this study were taken from 6,461 breeding records of cows raising at general farms in 8 Hanwoo(native cattle) pure breeding areas from June, 1984 through November, 1985. The recycling rate within 30 days, 31 to 60 days, and 61 to 90 days postpartum was 7.5%, 40.0%, and 32.8%, and it amounted to 80.3%, while the non-recyling rate up to 120days postcalving was 8.4%. Conception rate according to insemination(AI) frequencies was 65.7% at 1st AI, 21.3% at 2nd AI, and 8.4% at 3rd AI, respectively. It amounted to 95.4% up to 3rd AI. Clving rate during the spring time was the highest, 39.6%, and tended to be reduced according to summer(31.6%), autumn (16.3%), and winter (12.5%). Spring and summer were the highest seasons for pregnancy and their gestation rates are 33.7% in spring and 39.2% in winter, respectively. The days from calving to estrus and conception, and calving interval of the cows, which calved two or three times, tended to be reduced. However, the more parities, the more they are extended. According to parities, gestation length and services per conception showed irregular tendencies.

• Journal of Embryo Transfer
• /
• v.27 no.3
• /
• pp.133-139
• /
• 2012

This study was carried out to develop the useful inducing method of estrus for Korean native cows. Under the condition of estrus induction by administering $PGF_{2{\alpha}}$ for the cows in which corpus luteum (CL) in ovaries was detected by ultrasonography, ovarian responses and the changes of progesterone ($P_4$) concentration against $PGF_{2{\alpha}}$ compared with conception rate were observed in cows and heifers. In inducing estrus administering $PGF_{2{\alpha}}$. to the cows which has corpus luteum in ovaries, ovarian reponses, the changes of progesterone concentration, and conception rate were identified and compared. The results attained from the studies were as follows. Significant decreases of CL in size over time after $PGF_{2{\alpha}}$ administration were detected in both cow and heifer groups (p<0.001), but not different between groups in the CL regression rate (p>0.05). In addition, the percentage changes relative to the plasma $P_4$ concentration on day 1 after $PGF_{2{\alpha}}$ treatment were decreased to below 1ng/ml. The growth rate of follicle was observed as 31% on day 1 and 42% on day 2 in cows, and 34% on day 1 and 97% on day 2 in heifers, resulting that growth of heifers are faster than that of cows (p<0.05). The conception rate after $PGF_{2{\alpha}}$ treatment were 60.5% and 64.2% in cows and heifers, respectively. It also indicated that the conception rate after estrus observation with $PGF_{2{\alpha}}$ injection was as high as 66.6% while that with timed-artificial insemination (TAI) regardless of the estrus observation was 56%, which means the pregnancy rate of artificial insemination after estrus observation was higher than that of TAI (p<0.05). In the result of all above, there were significant decreases in CL size and the plasma $P_4$ concentration by days but rapid growth in follicles, which has no differences in cows and heifers. The conception rate was commonly high after estrus observation and more than 50% under TAI.