• Korean Journal of Animal Reproduction
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• v.10 no.1
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• pp.49-57
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• 1986

Studies were conducted to investigate the relationship between hormone leveles and nutritional levels for improving performance of Cheju native cattle. In June 1984 a trial was initiated using 8 Cheju native calves after weaning, fed at two su, pp.ementary feeding levels (NRC 100% and 70%). The body weight, breedng performence, change in progesterone level during pregnancy and estrus cycle were evaluated. Mean body weight at 6 months of age was 155kg when fed 100% NRC ration but it was only 137kg when heifers received the 70% NRC ration. At 10, 15 and 20 months of age the body weight was 66, 160 and 115kg, respectively, showing that heifers fed the standard ration gained weight rapidly (P<0.01). Average size of the lefe ovary in the standard group was 2.1${\times}$1.6cm and right ovary was 2.6${\times}$1.8cm. However in the restricted feeding group the ovaries were found to be smaller. Diameter of graffian follicles showed a similar tendency to ovarian size in the two groups. The first oestrus in the standard feeding group a, pp.ared at 14.6 months when body weight was 265kg. Age at first calving was on average 28.9 months at a body weight of 436kg. On the other hand when heifers were fed the restricted ration the first oestrus a, pp.ared at 23.0 months at a body weight of 250kg. Average age at first calving was 38.9 months which was 10 months later than the average in the standard feeding group (P<0.01). In standard feeding group the progesterone level was 2.0ng/ml at two weeks after pregnancy and gradully increased up to 4 weeks and peaked at 18 weeks. This peak (6.4-6.5ng/ml) was maintained up to 24 weeks when progesterone level decreased until it reached 2.1ng/ml at the end of pregnancy. In the restricted group progesterone level up to 16 weeks followed a similar pattern to the standard group but there was a tendency in the restricted group to have lower progesterone levels(P<0.01). The standard and srstricted groups showed similar patterns of progesterone concentration during the oestrus cylce. There were no statistically significant differences in progesterone levels between standard and restricted groups but there was variation between induvidual animals.

• 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.

• Korean Journal of Veterinary Research
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• v.32 no.2
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• pp.259-265
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• 1992

A study was conducted to improve the reproductive performance of Korean native goats. The length of estrous cycle and plasma progesterone concentrations during each cycles were determined by both radioimmunoassay and estrus behaviours, and the results were used in the early pregnancy diagnosis. The estrous cycles were classified into the short(l8 days or shorter, average 16.7 days), normal(19 to 22 days, average 20.9 days) and long(23 days and longer, average 23.8 days)cycle. The average length of the 19 estrous cycles was 20.8 days. Plasma progesterone concentrations in 12 normal cycles were the lowest(0.10 ng/ml) at estrus, remained high from 6 to 16 days(range : 4.43~7.93 ng/ml) and drastically decreased thereafter to reach minimal concentrations at the next estrus. Plasma progesterone concentrations were measured for early pregnancy diagnosis at 0, 10 and 20 days after mating in the 12 Korean native goats. Plasma progesterone concentrations in the pregnant goats at 20 days after mating were significantly higher than in the non-pregnant goats(p<0.001). Of the 12 goats, 10 were confirmed pregnancy by both progesterone concentrations and kidding. The accuracy of the pregnancy diagnosis based on plasma progesterone concentrations was 100% for positive as well as for negative.

• Clinical and Experimental Reproductive Medicine
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• v.28 no.4
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• pp.295-300
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• 2001

Objective : To assess the effects of progesterone and acetyl-L-carnitine used after treated with Isolate�� gradient before semen cryopreservation-thawing on sperm parameters and membrane integrity. Material and Methods : From April 2001 to July 2001, ten normal male partner of couples who were visited in vitro fertilization (IVF) clinics. the semens were treated with $Isolate^{(R)}$ gradient before cryopreservation, spermatozoa was incubated with progesterone (1, 5 and $10{\mu}M$), acetyl-L-carnitine (2.5, 5 and $10{\mu}M$), or both (progesterone, $1{\mu}M$; and acetyl-L-carnitine, $5{\mu}M$) for 30 min. Results: There were no differences in sperm parameters and vital stain among isolate only treated group, progesterone (1, 5 and $10{\mu}M$), acetyl-L-carnitine (2.5, 5 and $10{\mu}M$) and both (progesterone, $1{\mu}M$; and acetyl-L-carnitine, $5{\mu}M$). But, in high concentration of acetyl-L-carnitine ($10{\mu}M$) treated group, sperm parameters and vital stain were decreased. The statistical method was used ANOVA (Kruskal-Wallis test) and p value was <0.01. Conclusions : Neither progesterone nor acetyl-L-carnitine show to be protective effect on the cryodamage assessed by sperm parameters and vital stain (eosin-Y stain) in normal sperm. High concentration of acetyl-L-carnitine ($10{\mu}M$), however, was harmful effect on cryoprevention.

• Asian-Australasian Journal of Animal Sciences
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• v.11 no.4
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• pp.416-421
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• 1998

The objective of this study was to investigate the responsiveness of hypophysis and gonads to synthetic GnRH among noncycling Murrah buffalo heifers at 24 months of age. The plasma FSH, LH, estradiol and progesterone levels were measured in blood samples collected at 1 hour before and upto 18th day subsequent to the administration of GnRH ($(200 {\mu}g)$) or saline (2 ml). The pretreatment levels of plasma FSH, LH estradiol and progesterone among GnRH treated heifers (N = 6) were $11.55{\pm}0.57ng/ml$, $0.68{\pm}0.06ng/ml$, $19.84{\pm}0.82pg/ml$ and $0.45{\pm}0.07ng/ml$ respectively. A quick elevation of FSH (p < 0.01) and LH (p < 0.05) within 5 min of GnRH administration was observed in all the heifers. The peak FSH ($74.97{\pm}18.63ng/ml$) and LH ($3.09{\pm}0.54ng/ml$) level was obtained at 30 min of GnRH administration. The elevated level of plasma estradiol on 5th to 18th day, FSH on 7th to 9th day (n = 3) and the progesterone on 13th to 18th day (n = 2) of GnRH injection was obtained. The study indicates that gonads of buffalo heifers at 24 months of age are responsive of GnRH induced gonadotropin release for folliculogenesis and luteal tissue formation

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.9
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• pp.1268-1273
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• 2003

Sixty postpartum lactating Friesian cows in 3 treatments at a commercial dairy farm were used to study the effect of using progesterone supplementation with GnRH and PGF2$\alpha$ synchronization with and without timed AI on fertility during summer. Cows in treatment1($Tr_1$) and treatment2 ($Tr_1$) were fitted with progesterone releasing intravaginal device (PRID) device and injected with 10 g GnRH agonist on $51{\pm}3$ d postpartum (pp). Seven days later, PRID was removed and cows received 25 mg PGF2$\alpha$. Two days later, $Tr_1$ cows received another injection of 10 g GnRH and timed AI 16-20 h later. Control cows received only 25 mg PGF2$\alpha$ $58{\pm}3d\;pp$. $Tr_2$ and control cows were AI at detected estrus. Serum progesterone for all cows was determined on days of injection, AI and 21, 23 and 28 d postinsemination. Pregnancy rates from first AI based on serum P4 concentrations on d 21, 23 and 28 postinsemination (50, 40 and 35%) and that based on rectal palpation 40-45 d postinsemination (30, 15 and 15% for $Tr_1$, $Tr_2$ and control cows, respectively) did not differ among the three groups. Whereas, pregnancy rate at 120 d pp for $Tr_1$ (65%) was higher (p<0.05) than that in $Tr_2$ (30%) or control (30%). The overall pregnancy rate was not significantly different (90, 90 and 75% for $Tr_1$, $Tr_2$ and control, respectively). Days open for cows in $Tr_1$ ($100.3{\pm}9$) was less (p<0.03) than that in $Tr_2$ ($130.9{\pm}9$) or control ($135.1{\pm}10$). Results indicate that using PRID device with Ovsynch program had significantly increased pregnancy rate and decreased days open compared to AI at detected estrus after synchronization with GnRH, PRID and PGF2$\alpha$ or synchronization with one injection of PGF2$\alpha$.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.6
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• pp.862-867
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• 1999

The present study was undertaken to determine the effect of administration of exogenous progesterone early in gestation on uterine levels of IGF-I mRNA and on embryo survival at day 25 of gestation in the pig. Forty-one prepubertal gilts were induced into oestrus with PG600 and artificially inseminated at their subsequent naturally occurring oestrus. Gilts were then randomly assigned to one of three groups. Gilts in the two treatment groups were injected intramuscularly with 50 mg of progesterone either from day 2 to 14 (N=14) or from day 4 to 14 (N=15) after breeding while those in the control group (N=12) were given corn oil (0.5 ml) from day 2 to 14. Between days 25 and 28 of gestation, gilts were slaughtered and reproductive tracts were recovered. Endometrial tissue (1 g) was collected and analysed for IGF-I mRNA levels using a reverse transcription-polymerase chain reaction, Progesterone treatment, starting either on day 2 or 4 after breeding, neither significantly increased embryo survival rate by day 25 of gestation nor altered IGF-I mRNA levels in uterine tissue. However, across all samples, the IGF-I mRNA level in the uterus was highly correlated with embryo survival rate (r=0.8193, p<0.01), supporting the involvement of IGF-I in the regulation of porcine embryo development.

• Journal of Practical Agriculture & Fisheries Research
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• v.4 no.1
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• pp.110-118
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• 2002

This study was conducted to investigate the physiology of optimal reproductive age in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. Thirty two cows were devided into 4 groups of treatments : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months of age and 0.5kg daily gain). The days of the first heat of treated cows were 263.3±6.4 days and average weight was 181.1±11.3kg. The conception rates of first insemination were 25%(T1) and 75%(T4), and the number of insemination of T3 and T4(both 1.5) was lower than those of T1 and T2(2.3 and 2.4), respectively. With regard to estrus return after the first parturition, T1, T2, T3 and T4 showed 66.2,76.7, 62.4 and 68.5 days, respectively, indicating the average days of estrus return was 65.7. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 began to be detected after 12months. Only 5(15.6%) out of 32cows showed normal estrus cycle and ovulation before 12 months. During the peri-parturition period, P4 concentration was rapidly decreased and there was no detection of P4 from parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results imply that the optimal reproductive age of Hanwoo heifers would be around at the 14 months of age, 110cm height and 265kg weight.

• Korean Journal of Animal Reproduction
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• v.26 no.2
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• pp.193-199
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• 2002

This study was conducted to investigate the optimal physiologic mating time in Hanwoo for protection to decrease of reproductivity and improvement of production of offspring. We observed 32 cows that were devide into 4 parts of treatment : T1(12 months of age and 0.5kg daily gain), T2(12 months of age and 0.8kg daily gain), T3(15 months of age and 0.5kg daily gain) and T4(18 months and 0.5kg daily gain). The first heat of treated cows was 263.3$\pm$6.4 days and average weight was 181.1$\pm$11.3kg. It was revealed the conception rates of first insemination were 25%(T1), 75%(T4) and number of insemination of T3 and T4(both 1.5) was lower than T1 and T2(2.3 and 2.4). In return of estrus after heifer's first parturition, they(T1, T2, T3 and T4) showed 66.2 days, 76.7 days, 62.4 days and 68.5 days respectively and the average was 65.7 days. Plasma progesterone(P4) concentration was nearly the same during the observation periods of treated cows and P4 was released just after 12 months. Only 5 cows (15.6%) in 32 were showed normal estrus cycle and ovulation before 12 months. Before and after parturition, P4 concentration was decreased fastly and then there was no detection of P4 from after parturition to 40 days after milking. P4 would be released again on 45 day after parturition. The results were summarized as that the optimal mating time of Hanwoo heifers was decided by the 14 months of age, 110 cm height and 265kg weight.

• Korean Journal of Animal Reproduction
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• v.5 no.1
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• pp.73-79
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• 1981

This study was conducted to find out the effects of estrogen and progesterone on body weight, uterine weight and serum prolactin levels on the growing female rats which were ovariectomized. For this purpose, 125 heads of rats (Wistar-Imamichi strain), 28 days old, were devided into 5 groups; OVariectomy(Ovx.), ovariectomy treated with estrogen(Ovx.+Est.), ovariectomy treated with progesterone(Ovx.+Prog.), ovariectomy treated with estrogen and progesterone(Ovx.+Est.+Prog.) and control group. Twenty-five heads of rats were arranged to each group, and changes of body weights were weekly checked. On the other hand, every 5 heads of rats in each group were sacrificed at 1, 2, 3, 4 and 5 weeks after treatments with time elapse for measuring concentrations of serum prolactin and for investigating the weights of ulterus. Prolactin concentrations in the serum were analyzed by radioimmunoassay. The results obtained are as follows; 1. The body weights were increased slightly in Ovx. in comparison with Ovx.+Prog., Ovx.+Est.+Prog., Ovx.+Est. and control groups, but there were not significant among the compared groups at all observation times. 2. The uterine weights in all treatment groups were decreased significantly (P<0.01) compared with control groups at all observation times. But the weights in Ovx. and Ovx.+Prog. groups were lower than those in Ovx.+Est. and Ovx.+Est.+Prog.. 3. Serum prolactin concentrations were increased slightly in control group in comparison with other groups at 1 and 2 weeks increased slightly in control group in comparison with other groups at 1 and 2 weeks after treatment. But compared with control group, the concentrations Ovx.+Est. and Ovx.+Est.+Prog. were high level, and those in other groups were low level in the order of Ovx. and Ovx.+Prog. groups at 3, 4 and 5 weeks after treatment. There were not significant among the compared groups at all observation times. 4. The results obtained in this study suggest that when ovariectomized rats receive 1$\mu$g estrogen and 3mg progesterone daily, that had no effect on body weight and serum prolactin concentrations while significantly effect on the weight of uterus.