• Journal of Embryo Transfer
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• v.23 no.4
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• pp.257-261
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• 2008

The objective of present study was to investigate the effect of seasons on reproductive performance of Hanwoo and Holstein heifers. Heat stress in summer or cold stress in winter stress to Hanwoo and Holstein heifers may bring reproduction failure, which would pose an important economic loss, even around Daegwallyeong region located in high mountainous area. Seasonal differences in the serum levels of LH, FSH and progesterone ($P_4$) in response to environmental factors (hot and cold) out of 20 pubertal Hanwoo heifers in Daegwallyeong, Gangwon Province and 20 non-lactating Holstein heifers in Chonan city of Republic of Korea at 2-3 years of age were compared. Blood samples for hormonal analysis were from jugular vein after detection of estrus repeatedly over four seasons within four-week intervals (Spring: May to June, Summer: July to August, Autumn: October to November and Winter: January to February). In Hanwoo heifer population, averages of LH and FSH concentration in spring and in summer were greater compared to those in winter (p<0.05). LH or FSH levels tended to be greater (p=0.06) in spring and less (p=0.09) in winter compared to the levels in autumn. Only in summer, cattle seemed to show lower LH or FSH secretion (p<0.05). Similar to the results in Hanwoo heifers, the serum concentrations of LH and FSH in Holstein heifers decreased further by heat stress in summer when P 4 levels were high during luteal phase. The results demonstrate significant effect of summer heat on reproduction of Hanwoo or Holstein heifers. Although parameters indicating the extent of heat stress were not measured in this study, we suggest that serum hormone levels could be considered as successful indicators of summer heat stress condition for Hanwoo and Holstein heifers even under rather cool summer climate.

• Reproductive and Developmental Biology
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• v.38 no.3
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• pp.129-136
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• 2014

This study was carried out to elucidate the effect of antibiotic-free rearing system(ARS) on cortisol level, stress hormone, and fatty acid content in the edible muscle tissues, that were of M. longissimus in Hanwoo. These cattle were reared in two different systems including antibiotic-free (ARS) and conservative system (CRS). To increase the experimental reliability, the muscle samples were purchased 3 times from 3 Korean brands of beef produced with ARS or CRS. In the muscle tissue, cortisol level was significantly lower in ARS than CRS, (p=0.0176). But the levels of total saturated- and unsaturated-fatty acids were not significantly different between ARS and CRS (p>0.05). Of total fatty acids, the total saturated fatty acid tended to be greater in CRS and the total unsaturated fatty acid tended to be greater in ARS. However, of the total unsaturated fatty acids, the level of n-6 unsaturated fatty acids was significantly higher in ARS than CRS (p=0.0040). Especially, ${\alpha}$-linolenic acid (ALA) and ${\gamma}$-linolenic acid (GLA) levels were significantly higher in ARS (p<0.01). The n-6 fatty acid content and cortisol level in muscle tissue were negatively correlated at p=0.0140. In conclusion, ARS may produce beef with higher quality which contains lower cortisol and greater n-6 fatty acids, such as ALA and GLA.

• Reproductive and Developmental Biology
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• v.37 no.1
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• pp.35-40
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• 2013

The objective of this study was to investigate the effects of abnormal ovarian cycles after superovulation treatment of Holstein Donor Cows. CIDRs were inserted into the vaginas of twenty two head of Holstein cows, regardless of estrous cycle. Superovulation was induced using folliclar stimulating hormone (FSH). For artificial insemination, donor cows were injected with $PGF_2{\alpha}$ and estrus was checked about 48 hours after the injection. Then they were treated with 4 straws of semen 3 times, with 12-hour intervals. Embryos were collected by a non-surgical method 7 days after the first artificial insemination. The cows were considered to have resumed ovarian cyclicity on the day of ovulation if followed by regular ovarian cycles. Seventy two point seven percentage of the cows(16/22) had normal resumption of ovarian cyclicity(resumption within 40 days after superovulation), and 27.3%(6/22) had delayed resumption(resumption did not occur until>40 days after superovulation). Delayed resumption Type II(first ovulation did not occur until ${\geq}40$ days after superovulation, i.e. delayed first ovulation 13.6%) were the most common types of delayed resumptions. The mean numbers of total ova from < 10 and $10{\leq}$ of corpora lutea(CL) was $7.8{\pm}1.8$ and $12.7{\pm}2.7$, respectively. The number of transferable embryos differed between < 10 and $10{\leq}$ CL was $5.4{\pm}1.3$ and $8.1{\pm}3.4$, respectively. Four point five percentage of the cows(1/22) did not resumption their ovarian cyclicity until 60 days after superovulation treatment. Diverse researches on the superovulation treatment method that is suitable for high-producing Holstein donor cows would contribute to preventing ovarian cyclicity disorder, as well as to the early multiplication of cows with superior genes by increasing the utilization value of donor cows.

• Journal of Embryo Transfer
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• v.22 no.1
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• pp.47-51
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• 2007

The objective of this study was to improve the reproductive ability of Thoroughbred mares with artificial estrous regulation by hormone treatments and artificial illumination. The results were as follows; Estrous detection in cycling mares which were treated $PGF_2{\alpha}$ or altrenogest administration was all 100%, and pregnancy rates were 95.2% and 71.4%, respectively. Estrous detection was 100% within March when altrenogest was administered alone or together with estradiol for non-pregnant mares in the previous year. Interval to estrous detection after altrenogest administration was 4.3 days in single administration of altrenogest and 3.7 days in combined administrations of altrenogest and estradiol, respectively Interval to ovulation after estrous detection were 2.7 and 2.5days, respectively. Pregnancy rate following single altrenogest administration was 80.0%. Estrous detection and pregnancy rates by artificial illumination in non-pregnant mares were 92.9% and 46.9%, respectively. These results show that estrous synchronization of mares during breeding season will be able to improve the pregnancy rate, and altrenogest administration in non-pregnant mares in the previous year will be able to induce early reproduction and improve pregnancy rate In racing horses.

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.642-651
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• 1998

The accuracy of ultrasonography for determining the presence of a functional corpus luteum in subestrous dairy cows was investigated, using a radioimmunoassay for progesterone in plasma. Luteal status (high or low progesterone concentrations) was diagnosed in 534 cows, using B-mode transrectal ultrasonography. Accuracy of ultrasonography was 96.3% and 88.8% in the cows with and without functional corpus luteum, respectively. In 362 cows diagnosed with functional corpus luteum by ultrasonographic examination, 20 cows were diagnosed with the non-functional corpus luteum by analysis of plasma progesterone concentrations (false positive). In 172 cows with non-functional corpus luteum by ultrasonographic examination, 13 cows were diagnosed with the functional corpus luteum based on plasma progesterone assay (false negative). Most of the corpus luteum with well-defined border and homogeneous echotexture were diagnosed with functional corpus luteum. All cows that were not detected a corpus luteum by ultrasonographic examination were diagnosed as non-functional corpus luteum. The corpus luteum of cows that were diagnosed with false positive appeared homogeneous echotexture and above 15 mm in diameter, but the corpus luteum was the non-functional corpus luteum within Day 5 (Day 0 is ovulation day) or after Day 19. The corpus luteum of cows that were diagnosed with false negative appeared heterogeneous echogenicity and below 15 mm in diameter, but the corpus luteum was the functional corpus luteum after Day 5 or around Day 17. It was concluded that accuracy of ultrasonography was excellent for determining the presence of a functional corpus luteum in subestrous dairy cows. The corpus luteum that was diagnosed with false positive or false negative was the developing or regressing states. Thus, ultrasonography was required a serial examination of two or three times accurately diagnosing these corpus luteum.

• Development and Reproduction
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• v.22 no.2
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• pp.155-163
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• 2018

This study aimed to investigate changes in the activity and mRNA expression of plasminogen activators (PAs) induced by $17{\beta}$-estradiol ($E_2$), human chorionic gonadotropin (hCG), and interleukin-$1{\beta}$ ($IL-1{\beta}$) in porcine endometrial cells. Endometrial cells were isolated from the epithelium and cultured to 80% confluence. They were then treated for 24 h with $E_2$ (0.2, 2, 20, and 200 ng/mL), $IL-1{\beta}$ (0.1, 1, 10, and 100 ng/mL), and hCG (0.5, 1, 1.5 and 2 IU/mL). mRNA expressions of urokinase-type (uPA) and tissue-type (tPA) PAs were analyzed using reverse transcription PCR, and activities were measured using a PA activity assay. mRNA expressions of uPA and tPA increased with $E_2$ treatment; however, this was not significant. Similarly, treatment with hCG did not influence the mRNA expressions of PAs. Interestingly, treatment with 0.1 ng/mL $IL-1{\beta}$ significantly reduced the mRNA expression of uPA, but did not affect that of tPA. Treatment with 2, 20, and 200 ng/mL $E_2$ increased PA activity compared with the control group; treatment with 0.1 and 1 ng/mL $IL-1{\beta}$ significantly increased PA activity compared with the other $IL-1{\beta}$ treatment groups, whereas treatment with 10 and 100 ng/mL $IL-1{\beta}$ decreased. Treatment with 2 IU/mL hCG increased PA activity compared with the other treatment groups, although there were no significant differences between the hCG and control groups. In conclusion, the activity and mRNA expression of PAs were differently regulated by the hormone/cytokine and its concentration in porcine endometrial cells. Therefore, understanding PA regulatory mechanisms may help to improve the reproductive potential of domestic animals.

• Journal of Life Science
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• v.23 no.8
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• pp.1064-1072
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• 2013

Circadian rhythm is controlled by hormonal oscillations governing the physiology of all living organisms. In mammals, the main function of the pineal gland is to transform the circadian rhythm generated in the hypothalamic suprachiasmatic nucleus into rhythmic signals of circulating melatonin characterized by a largely nocturnal increase that closely reflects the duration of night time. The pineal gland has lost direct photosensitivity, but responds to light via multi-synaptic pathways that include a subset of retinal ganglion cells. Rhythmic control is achieved through a tight coupling between environmental lighting and arylalkylamine-N-acetyltransferase (AANAT) expression, which is the rhythm-controlling enzyme in melatonin synthesis. Previous studies on the nocturnal expression of AANAT protein have described transcriptional, post-transcriptional, and post-translational regulatory mechanisms. Molecular mechanisms for dependent AANAT expression provide novel aspects for melatonin's circadian rhythmicity. Extensive animal research has linked pineal melatonin for the expression of seasonal rhythmicity in many mammalian species to the modulation of circadian rhythms and to sleep regulation. It has value in treating various circadian rhythm disorders, such as jet lag or shift-work sleep disorders. Melatonin, also, in a broad range of effects with a significant regulation influences many of the body's physiological functions. In addition, this hormone is known to influence reproductive, cardiovascular, and immunological regulation as well as psychiatric disorders.

• Korean Journal of Environmental Biology
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• v.32 no.4
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• pp.271-285
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• 2014

Aluminum flows into the river from the abandoned mine leachate, industrial wastewater, and sewage and is responsible for acute toxicity in aquatic organisms. Recently, the number of reports have indicated the increased toxicity in a variety of aquatic organisms' due to the aluminum toxicity. In this study, we reviewed the toxicity of aluminum on aquatic invertebrates, fishes and amphibians and suggested the guideline for management of aluminum residues in aquatic environment and strategies for aluminum toxicity evaluation. In aquatic animals aluminum complexes evoke gill dysfunction primarily, the cytotoxicity, genotoxicity, oxidative stress, disruption of endocrine function, reproductive success, metabolism and homeostasis. Notably, at environmentally relevant concentration, aluminum complex can alter the hormone levels in fish in acidic condition. Further, since the solubility of aluminum is higher in the acidic and basic conditions, thus it is likely that the toxic effects of aluminum may not only occur in acidic water near the abandoned mines but also in lakes and rivers, where pH is raised by algal bloom.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.376-383
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• 2003

To establish the differential diagnosis and treatment method in bovine ovarian cysts, specially ovarian cysts with corpus luteum, serum progesterone concentration, rectal palpation and ultrasonography for measuring the cystic wall thickness and diameter of cyst and corpus luteum were investigated from 1,188 dairy cows with ovarian cysts. The plasma progesterone concentrations were 0.3$\pm$0.4 (mean$\pm$SD) ng/ml in 629 cows with follicular cysts, 3.7$\pm$1.1 ng/ml in 431 cows with luteal cysts, and 3.8$\pm$1.2 ng/ml in 128 cows with coexist of ovarian cysts and corpus luteum, respectively. The cystic wall thickness by ultrasonography were 1.6$\pm$0.4 mm in 629 cows with follicular cysts, 4.2$\pm$1.5 mm in 431 cows with luteal cysts, and 1.6$\pm$0.6 mm in 128 cows with coexist of ovarian cysts and corpus luteum, respectively. The days from initial treatment to insemination in follicular cysts were 28.1$\pm$6.9 days in treatment of GnRH alone, 15.9$\pm$2.9 days in combination of GnRH and dinoprost, and 15.1$\pm$3.1 days in combination of GnRH and cloprostenol. The percentages of cows conceived within 100 days after initial treatment were 61 %, 68% and 73% in treatment of GnRH alone, combination of GnRH and dinoprost, and combination of GnRH and cloprostenol, respectively. The days from initial treatment to insemination in luteal cysts were 3.8$\pm$0.6 days in treatment of dinoprost alone and 3.8$\pm$0.7 in cloprostenol alone. The percentages of cows conceived within 100 days after initial treatment were 69.5% and 68.5% in treatment of dinoprost and cloprostenol, respectively. The days from initial treatment to insemination in coexist of cysts and corpus luteum were 3.7$\pm$0.7 days in treatment of dinoprost alone and 3.8$\pm$0.6 in cloprostenol alone. The percentages of cows conceived within 100 days after initial treatment were 87% and 84% in treatment of dinoprost and cloprostenol, respectively. These results suggest that the best choice for treatment agents in ovarian cysts were combination of GnRH and PGF$_2$$\alpha$ in follicular cysts, and the PGF$_2$$\alpha$ in luteal cysts and in coexist of cysts and corpus luteum, respectively. In conclusion, it is suggest that ultrasonography is useful diagnostic tool for diagnosis and selection of treatment remedy in cystic ovaries of bovine.

• Journal of Embryo Transfer
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• v.28 no.4
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• pp.315-318
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• 2013

This study was conducted to investigate the changes of hormone levels of serum progesterone (P4) and estradiol-$17{\beta}$ (E2) in sows of Landrace (L), Yorkshire (Y) and F1 (L ${\times}$ Y) (respectively n=3) with excellent ability, and to provide a baseline data for improving reproductive performance. In this experiment, the sows at the age of 12 months or more were used. The sows were fed by two way methods, one is conventional methods and the other is 3 days-flushing feed before estrus. Each pig's blood was collected in 3, 6, 9, 12, 15 and 18 days after the estrus for the analyses of P4 and E2. Serum was separated by centrifugation for 15 min. with 3,000 rpm. Progesterone and estradiol-$17{\beta}$ were measured by immunochemical assay (ELIZA test). In conventional feeding, serum progesterone levels were significantly (p<0.01) higher in F1 than in L and Y. No significant differences in P4 concentrations were seen between the L and Y of sows. Serum E2 levels were similar the serum progesterone levels. In the case of flushing feed, the tendency of hormonal changes were similar to conventional methods. But almost of hormonal levels were a little higher than that of conventional methods. P4 level of L and Y in flushing feed were significantly different (p<0.01). Serum E2 level of Y in flushing feed was significantly different among the breeds (p<0.01). These results were similar to the tendency of hormonal changes in general sows and moreover, flushing feed is known to develop the swine production, these results proved the fact of the methods. And these results suggested that more studies about hormonal changes in sows according to seasonal and nutritional factors should be needed.