• Korean Journal of Veterinary Research
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• v.62 no.2
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• pp.15.1-15.8
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• 2022

The objective of this study was to identify risk factors for repeat breeder dairy cows and their impact on reproductive performance. The characteristics of 1,504 cows, including their peripartum health, nutrition, production, and reproduction, were collected. Cows with metabolic disorder were significantly more likely (odds ratio [OR], 2.47; p < 0.001) and cows with clinical endometritis tended to be more likely (OR, 1.35; p < 0.1) to become repeat breeders than cows without metabolic disorder and clinical endometritis, respectively. Cows initially inseminated > 80 days after calving were less likely (OR, 0.78; p < 0.05) to become repeat breeders than cows initially inseminated ≤ 80 days after calving. As a result, repeat breeding in dairy cows resulted in a 90 day longer (p < 0.0001) mean interval from calving to pregnancy. In conclusion, postpartum metabolic disorder, clinical endometritis, and a short interval from calving to initial insemination were risk factors for repeat breeder dairy cows, resulting in a severely impaired reproductive performance.

• Korean Journal of Animal Reproduction
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• v.9 no.1
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• pp.66-71
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• 1985

After the induction of estrus by the PGFF2$\alpha$-GTH combination on the 118 repeat breeder cow during of 6-13 days of the estrus cycle, the effects of GTH, antibiotics, antibiotics-GTH combination were compared. The results of this study, the following conclusion were obtained: 1. The rate of estrus was reduced the administration of GTH before the administration of PGF2$\alpha$. 2. The rate of ovulation delayed was 24.6% in the group with the administration GTH, but 34.1% without the administration GTH. Duration of ovulation was shortened by GTH. 3. The impregnation induction by the administration of PGF2$\alpha$, PGF2$\alpha$-antibiotics, PGF2$\alpha$-GTH-antibiotics were 41.7%, 69.5%, 55.6% and 80.8% respectively injection in the uterus was more effective than the administration. Before or after the A.I., the above combination was most effective. 4. In antibiotics sensitivity test in vitro of the intravagina bacteria, 5.0%, 12.7% and 60.0% of bacteria were sensitive to Penicilline, Streptomycin and Gentamicin respectively.

• Journal of Embryo Transfer
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• v.30 no.1
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• pp.59-64
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• 2015

Intensive genetic selection has resulted in modern dairy cow with very high milk yields but reduced fertility, due mainly to an increase in reproductive disorders. The study was conducted to estimate the proportion of reproductive disorders among dairy cattle. The factors analyzed were; milk yield, cow parity, periparturient disorders, and reproductive status. The result of this study showed the incidence of reproductive disorders in high yielding dairy cows was prevalent. Repeat breeding was the major postpartum reproductive problem comprising (42.3%) of the samples. Higher reproductive disorders were also associated with lower parity. These disorders subsequently reduced reproductive performance by prolonged intervals from calving to first artificial insemination and from calving to pregnancy. Abnormalities in the reproductive system such as repeat breeder, silent heat, anestrous and ovarian cysts, as well as lower fertility have been recorded during the summer months (June to August). In conclusion, the study revealed that incidence of repeat breeder is mostly prevalent in dairy cows. Moreover, the incidence of reproductive disorders was higher in summer season and hence appropriate preventive and or therapeutic measures as per the type of abnormalities need to be undertaken.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.11
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• pp.1670-1676
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• 2007

Fifty repeat breeder (RB) Friesian cows were allocated to five groups of 10 cows each, to determine the effect of progesterone (P4) supplement on P4 concentrations and pregnancy rates during the periods of corpus luteum (CL) formation and development between days 2-7 and 7-12 following a spontaneous or $PGF_{2{\alpha}}$-induced estrus. Cows were artificially inseminated during $PGF_{2{\alpha}}$-induced (PGF-P4-d2 and PGF-P4-d7 groups) or spontaneous (S-P4-d2, S-P4-d7, and control groups) estrus. Progesterone-releasing intravaginal device (PRID) devoid of estrogen capsule were inserted either on d 2 (PGF-P4-d2 and S-P4-d2 groups) or d 7 (PGF-P4-d7 and S-P4-d7 groups) post-insemination and left in place for 5 days. Control cows did not receive any treatment. Blood samples were collected for progesterone analysis from all cows once daily for 4 days starting on the day of estrus (d 0) and once every 3 days thereafter until d 22. Progesterone treatment by day interaction accounted for higher plasma P4 in treated than non-treated control cows. Progesterone concentrations differed significantly (p<0.05) during metestrus (d 2 to d 7) but not during diestrus (d 7 to d 12). $PGF_{2{\alpha}}$ treatment, lactation number, service number or their interactions did not affect progesterone concentrations and pregnancy rates. Therefore, cows were grouped according to the day of P4 supplement irrespective of the $PGF_{2{\alpha}}$ treatment. Progesterone supplement on d 7 but not d 2 significantly increased (p<0.03) pregnancy rates in repeat breeding cows with four or more previous services but not in cows in their third service. In conclusion, post-insemination P4 supplement to repeat breeding cows with four or more previous services improved pregnancy rates and should be advocated when no specific reason for infertility is diagnosed. Further studies with larger numbers of repeat breeding cows under field conditions are needed to ascertain the findings of this study.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.177-184
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• 2005

This study was conducted to investigate the effects of recombinant bovine somatotropin (rbST) injection on conception and parturition rates in normal or repeat breeding Hanwoo. We treated 462 cows containing 79 repeat-breeding cows of multiparous and allocating 5 treatment groups. Treatment 1 (T1) was injection of 2ml saline (for pseudo treatment), T2 was one injection of rbST 250mg into the tailhead region at the estrus, T3 was twice injection of rbST 250mg both at the time of insemination and again 10 to 14 day later, T4 was once injection of rbST 500mg at insemination and T5 was twice injection of 500mg rbST both at the time of insemination and again 10 to 14day later respectively. In rbST treated groups, timed artificial inseminations (TAI) were performed fellowing estrus synchronization. 100 us GnRH was injected into the scapula region on Day 0, 25mg $PGF_2{\alpha}$ was injected on Day 7 for degeneration of corpus luteum (CL) and 100ug GnRH was injected for inducing the synchronization. The results are as fellows; When normal Hanwoo were inseminated once with rbST administration, the pregnancy rate of T2 $(67.5\pm18.48\%)$ were higher than control $(52.4\pm9.72\%)$, while the pregnancy rate of T4 $(63.3\pm5.77\%)$ were significantly higher (p.<0.05) than control $(39.3\pm12.89\%)$ in repeat breeder Hanwoo. The parturition rates of normal Hanwoo were no differences among the treatments but were significant different in repeat breeder Hanwoo (p<0.05). When the estrous was induced by Ovsynch and inseminated once with rbST administration, the pregnancy rates of T2 was $12.5\%$ higher than control in normal Hanwoo, T4 $(80.0\%)$ was highest among the treatments (p<0.05) in repeat breeder Hanwoo. When normal Hanwoo were inseminated once with rbST administration, the pregnant period was $282.7\~284.8$ days and the body weight was $25.1\~25.9kg$, there were no difference among the treatments. The ratio of sex was almost same without T4 (male vs. female=18:9). In repeat breeder Hanwoo, pregnant period was 280.4~289.3 day and body weight was $23.0\~26.6kg$, it had no difference among the treatments. The sex ratio were similar to normal Hanwoo except T4 (M : F=2 : 8). In conclusion, the pregnancy and parturition rate by once insemination could be improved by the administration of rbST 250mg in normal Hanwoo or 500mg in repeat breeder Hawoo.

• Korean Journal of Animal Reproduction
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• v.16 no.2
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• pp.175-184
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• 1992

These experiments were investigate the effects of bacterial infection of uterus and vagina during bovine embryo transferring on the development of embryo. We examined the distribution of reproductive disordered cow by akind of disease, identified the bacteria isolated from the vagina of those cows and bacterial infectin of media and its treatment with several kinds of antibiotics at that. The results obtained were summarized as follows ; 1. The total 592 reproductive disordered cows were caused by ovarian dysfunction(43.4%), ovary-uterus complication(24.5%), endometrities(17.7%), and repeat breeder(12.0%). 2. The main bacteria among 11 kinds of bacteria(113 colonies) was E. coli(38 colonies, 33.6%). Likewise, E. coli was propotioned to 23 and 22.7% among bacteria from vagina of endometritis and repeat breeder, respectively. 3. The sensitivities of viginal bacteria to pencillin and streptomycin were 6.2 and 4.4% respectively, but those to gentamycin and chloramphenicol were 22.1 and 16.8%, respectively. The similar sensitivities were found in the embryo recovery media. 4. The rates of bacterial infection of recovery medim and that of abnormal development of embryo were 75 and 80%, respectively. 5. The antibiotic sensitivity assay of ova recovery media showed gentamicin and chloramphenicol gave better results than streptomycin and penicillin. 6. The developmental rate of 1-cell stage mice embryos was 34.0% in bacterial infected culture media, but was 40.0, 58.0, 40.0 or 30.0% with the treatment of kanamycin, gentamycin, chloramphenicol, streptomycin, or penicillin, respectively.

• Korean Journal of Animal Reproduction
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• v.12 no.1
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• pp.20-23
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• 1988

The 3211 Korean native cows raised in Muan, Milyang were investigated for the purpose of finding reproductive rate of cows that retained fetal membrane for two years from April, 1981 to March, 1983. The results obtained were summarized as follows ; 1. The incidence of retained fetal membrane was found in 64 cows(1.98%). 2. The day to first estrus was similar to normal postpartum period unless concurrent genital infection occured. 3. Conception rate of cows that retained fetal membrane was 32.7%, 10.9%, 5.2% and 3.6% at the first, second, third and forth service, respectively and non pregnant cow was 47.6%. 4. Reproductive disorder of non pregnant cows was the highest in repeat breeder and the effect of treatment was very low.

• Journal of Veterinary Clinics
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• v.1 no.1
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• pp.33-40
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• 1984

The number of dairy cows diagnosed and treated at Hyup-dong Animal Hospital from July 1983 to June 1984 was amounted to 3,073 heads of Holstein breed and the result of analysis of diseases was as follows : 1. In the topographic diagnostic categories, 41.23% of all cases involved the urogenital system and were observed most prominent. Next were digestive system (22.10%), general and regional (14.55 %), respiratory system (8.20%) and musculoskeletal system (7.06%) in decreasing order. 2. In urogenital system 50.20% of all diagnosis involved metritis and this were most prominent disease. Next were repeat breeder(15.31%), retained placenta (12.79%) and ovary disfunction(9.40 %) in decreasing order. 3. In digestive system 36.82% of all diagnosis involved enteritis and were most prominent. Next were abomasal displacement (29.31%), lumen indigestion (20.32%) and lumen bloat (9.57%) in decreasing order 4. In general and regional diseases, 52.80% of all diagnosis involved ketosis and were most prominent. Next were milk fever (25.50%), downer cow (5.82%) and omphalitis (4.47%) in decreasing order. 5. In respiratory system, 82.54% of all diagnosis involved upper respiratory tract infections and were most prominent. Next were pneumonia (15.87%). 6. In musculoskeletal system, 49.31% of all diagnosis involved foot rot and were most prominent. 7. In milk secreting system, 61.64% of all diagnosis involved mastitis and ere most prominent. Next were stenosis of teat canal (16.35%). 8. Among the individual disease entities, endometritis marked 20.7%, enteritis 8.13%, ketosis 7.68% upper respiratory tract infection 6.77%, repeat bheeder 6.31%, retained placenta 5.27%, abomasal displacement 4.69%, and lumen impaction 4.49%, respectively of total 3,073 cases in decreasing order.

• Current Research on Agriculture and Life Sciences
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• v.4
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• pp.102-108
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• 1986

This study was carried out to examine the effects of seasonality, age, abnormalities of reproductive tract and the frequency of superovulatory treatments on the superovulatory responses and rate of pregnancy in repeat breeder for embryo transfer. Thirty eight eggs were obtained from 6 donors by flushing the uterine horns and 33 embryos were transfered to 33 recipients. (29 holstein heifers, 3 holstein cows and 1 Korean native heifer). From this study, the following results could be obtained: 1. It seemed that spring (Feb.-Apr.) was the better season than any others to produce good embryos. Rate of pregnancy decreased significantly after August because of low heating rate. 2. Rate of pregnancy in the cows with normal reproductive tract showed much better superovulatory responses (80%) than the cows with abnormal reproductive tract (33%), as expected. 3. 8 years old cows produced higher rater of pregnancy than 4 years old cow (79.3 vs 50), and also in superovulatory responses, 8 years old cows showed slightly better results than 4 years old cow. 4. The number of ovulated eggs and rate of pregnancy in the repeated superovulatory treatment more than once were 41 eggs and 85.7%, and those of the donors treated the first superovulatory treatment were 32 eggs and 68.4%, respectively. 5. These results are showing the possibility that utilizing the repeat breeders as donors in embryo transfer could be able to elevate their economic values.

• Korean Journal of Veterinary Research
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• v.37 no.4
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• pp.925-934
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• 1997

This study was directed at inducing the production of antibodies by immunizing heifers with bovine sperm antigen and on measuring the serum antibodies using indirect immunofluorescence assay(IFA) and agglutination test. The effect of antisperm antibodies on fertilizing capacity of bovine spermatozoa was evaluated. 1. Three heifers between 12- and 15- month old were immunized with bovine spermatozoa or phosphate-buffered saline. In heifers immunized with bovine spermatozoa serum IgG level was highest between 3 weeks and 5 weeks postimmunization detected by IFA. The antibody levels persisted through week 7 and slowly declined until week 20 and then antisperm antibodies were localized on spermatozoa. The fluorescent antisperm antibodies were detected at 2~20 weeks and at 6~9 weeks postinoculation on acrosome and tail, respectively. Among 21 sera from repeat breeder cows, only one cow has shown positive antisperm antibody response detected by IFA. 2. In spite of vital rate of bovine sperm after swim-up was not significantly affected by different concentration of antisperm antibodies in sera, the numbers of bovine sperm after swim-up were significantly reduced in proportion to the increased concentration of antibodies. Above 1/512 dilution of antibody neither influence on vital rate and numbers of bovine sperm nor sperm agglutination after swim-up. The study has also shown that the vital rate and number of sperm after swim-up and capacitation were also significantly reduced by the addition of antisperm antibodies. Although antisperm antibodies did not influence on the acrosome reaction rate of sperm during swim-up, did significantly reduce the sperm acrosome reaction rate after capacitation. The studies have resulted that the bovine antisperm antibodies can prevent the sperm motility by agglutination and block the capacitation and acrosome reaction of bovine sperm.