• Development and Reproduction
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• v.6 no.2
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• pp.123-129
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• 2002

Leptin, a product of the obese gene, is associated not only with obesity but also with female reproductive function, but it has not yet been ascertained whether leptin acts directly on the ovary or indirectly via the hypothalamus-pituitary pathway. Therefore, the object of this study was to investigate the expession of leptin and its receptor in the rat ovary by immunohistochemistry and RT-PCR during the estrous cycle. Immunohistochemistry results showed that leptin was stained in the theca cells and in part of granulosa cells in atretic follicles, whereas leptin receptor was localized in the interstitial cells and ova in preantral follicies. In particular, leptin and its receptor in atretic follicles displayed more intensive staining compared to those in normal follicles. During the estrous cycle, the mRNA expression of leptin and its receptor in the ovary was detected by RT-PCR and estradiol, progesterone, and leptin levels in the serum was measured by ELISA. The leptin level in the serum on metestrous phase was significantly higher than that on estrous phase. Similar to leptin level, progesterone level increased on metestrous phase. Leptin mRNA was not detected throughout the estrous cycle, whereas leptin receptor mRNA was expressed on all phases of estrous cycle excepting the diestrous phase. These results suggest that leptin might be directly involved in the regulation of ovarian function in rat.

• Korean Journal of Animal Reproduction
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• v.22 no.4
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• pp.341-347
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• 1998

This study was conducted to determine changes in circulating progesterone and Insulin-like Growth Factor-1(IGF-1) concentrations according to daily gain of 0.5 and 0.7 kg ; from 33 weeks of age until the onset of regular oestrus cycles in the heifer of Hanwoo. In all animals, progesterone concentrations was undetectable until just before first oestrus. A small progesterone elevation of approximately 6 days duration(based upon the mean progesterone profile) preceded the first oestrus in 13 heifers. The mean age at first oestrus of the daily gain 0.7 kg(331.0$\pm$ 15.0 days) group was earlier than those of the daily gain 0.5 kg(358.9$\pm$7.9 days) group, and the mean weight at first oestrus of the daily gain 0.7 kg(236.0$\pm$4.7 kg) group was heavier than those of the daily gain 0.5 kg(224.8$\pm$9.7 kg) group. IGF-1 concentrations from day 3 to 15 of first oestrus were higher than those of the earlier luteal stage(Day 0~1) and the luteal regression stage (Day 18~20). IGF-1 concentrations according to the growth stage (from 33 weeks to 57 weeks) increased gradually. On the basis of these results, we suggest that the onset of first oestrus in Hanwoo heifer is about 345 day of age, and progesterone concentrations are closely related to the IGF-1 concentration.

• Journal of Veterinary Clinics
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• v.27 no.6
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• pp.693-697
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• 2010

This study, conducted with four leopard cats (Prionailurus bengalensis), used time-resolved fluoroimmunoassay (TR-FIA) to analyze estradiol and progesterone concentrations in fecal samples. We measured fecal samples taken during estrus period, diestrus period, pregnancy and non-pregnancy period. During estrus (February), the mean minimum estradiol concentration was $4.02{\pm}1.9$ng/g, and the mean maximum was $86.01{\pm}35.2$ng/g (dry fecal weight). During diestrus (November), the mean minimum estradiol concentration was $4.42{\pm}1.32$ng/g and mean maximum was $15.62{\pm}6.48$ng/g (dry fecal weight). Midgestation (April), the mean minimum progesterone concentration was $427{\pm}24.49$ng/g and the mean maximum was $1490{\pm}265.27$ng/g. During non-pregnancy (November), the mean minimum progesterone concentration was $71.25{\pm}29.61$ng/g and the mean maximum was $291.75{\pm}90.30$ng/g. These results suggest that steroid hormone analysis of feces using TR-FIA is a valid method for noninvasively determining ovarian activity associated with estrus and pregnancy in leopard cats. This study will contribute to building breeding management and reproductive plans for endangered species.

• Korean Journal of Animal Reproduction
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• v.25 no.3
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• pp.251-257
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• 2001

This study was carried out to investigate the effect of breed, parity, litter size, lactating period, and estrus interval on sow productivity traits in swine. Data from 492 heads of Landrace, Yorkshire or crossbred sow which were raised at Yonam College of Agriculture from March, 1998 to July, 2000 were analyzed for this study. The total number of pigs born (TN), the number of pigs born alive (NB), and the number of pigs suckled (NS) were greater in the crossbred sows than in the purebred. In TN and NB, the 3rd to 7th parities were greater than other parities, and the 8th parity was the lowest. The number of pigs stillbirthed (NSB) and the number of runt per litter tended to increase with the increase of TN. In addition, statistical analysis showed that parity had significant effect on most of traits. The current TN had highly significant effect on TN, NB and NS of the next parity As current TN increased, TN, NB, and NS of the next parity increased. The current lactating period also affected significantly for TN, NB, and NS of the next parity The sows which had the lactating period of 20∼21 days produced the greatest TN and NB in the next parity. Weaning to estrus interval(WEI) had significant effect on TN, NB, and NSB. Among WEI groups, the WEI group of 7∼13 days was the lowest in TN, NB and NSB.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.652-657
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• 2018

Breeding control in a farm is a very important factor affecting milk productivity. Breeding management is important for the early detection of estrus, and reliable, automatic, more accurate, and faster monitoring of the timing of dairy cows is essential for farmers. This study measured the accuracy of estrus using the estrus indications, changes in activities, rumination activities, ruminal temperature, and pH. The biomedical information device S1 used in this study provided an estrus notice using the rumen temperature, pH, cow activities, and number of drinking estimations, which were inserted in the rumen through the oral route. The S2 device was used in the estrus notice for the rumen activities and cow activities. The data collected on the instrument were collected at intervals of 2 hours per day at the reference days (RD: -7~-3, +7~+ 3) +2), 7 days before insemination, and 7 days after insemination. The activities of the S1 device used in this paper increased with increasing number of insemination days (-1: $12.5{\pm}1.03/day$; 0: $12.9{\pm}1.73/day$) compared to the reference day (RD: $10.2{\pm}1.0/day$). The activities of the S2 device was also found to increase from the reference day to the insemination day (0: $63.0{\pm}3.66$) compared to the reference day (RD: $40.3{\pm}2.68$). The number of daily drinks in S1 decreased from the reference day (RD: $5.9{\pm}0.89/day$) to before the insemination day (-2: $5.6{\pm}0.98$; -1: $5.7{\pm}0.96$); +2: $6.0{\pm}0.73$). The number of daily drinks on the insemination day (0: $6.3{\pm}0.86$; +2: $6.0{\pm}0.73$) was similar to the reference day. The number of daily rumination in S2 decreased from the reference day (RD: $493.8{\pm}10.92$) to the insemination day (-1: $390.2{\pm}13.36$; 0: $354.1{\pm}16.71$).

• Journal of Embryo Transfer
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• v.18 no.1
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• pp.61-68
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• 2003

Considerable attention has been focused on the cryopreservation of semen and estrus induction in dog, as consequence of poor productivity caused by long anestrus period, in order to enhance the productivity of youngs and to preserve the breeds. The objectives of this study were to improve reproductive efficiency of artificial insemination with fresh- and frozen-semen following estrus induction in dog. Fifty infertilie dogs (age 2~3 years) were selected fur the study and divided into three different estrus induction treatment groups. Group 1 : dogs (n=15) were given clomifene (0.1 mg/kg) orally f3r five days at 12 hr intervals. Croup 2: dogs (n=15) were given bromocriptine (50 $\mu$g/kg) orally for five days at 12 hr intervals, followed by single injection intravenously of 500 IU GnRH (Croup 3, n=20) when pro-estrus occurred. After being treated, the dogs were evaluated fur the rates of estrus induction and time interval lapses from treatment to beginning of the pro-estrus. The rates of pregnancy in estrus inducted dogs mated naturally compared to those inseminated artificially with ejaculated fresh semen and frozen-thawed semen. Estrus detection was performed using the method of vaginal smear and confirmed by the plasma progesterone assay. Pregnancy was confirmed by ultrasonograpy on day 25, 35 and 55 post insemination. The ejaculated semen was exposed to a mixture of Tris extender with cryoprotectant (Trisma, 81 mM; TES, 209 mM; citric acid, 6 mM; glucose, 5 mM; glycerol, 8%) and cryopreserved gradually by slow-cooling at 17 co above the surface of liquid nitrogen (L$N_2$) for 23 min. The use of fresh semen, the pregnancy rates were observed 66.6, 66.6, 75.0 and 83.3% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. The use of frozen-thawed semen, the pregnancy rates were observed 66.6, 33.3, 50.0 and 60.0% in natural estrus, clomifene induced, bromocriptine induced and a combination of GnRH and bromocriptine, respectively. No difference was observed in the number of offspring produced among natural estrus and treated groups inseminated with fresh or frozen-thawed semen. In conclusion, there was no significant differences in the pregnancy rate of dogs between group treated with a combination of GnRH and bromocriptine and group treated clomifene or bromocriptine only. However, frozen-thawed semen can be used successfully fur artificial insemination in dog.

• 월간낙농육우
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• v.35 no.7
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• pp.156-160
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• 2015

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.06a
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• pp.1-8
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• 2006

• Proceedings of the Korean Society of Embryo Transfer Conference
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• 2006.06a
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• pp.27-45
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• 2006

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2001.02a
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• pp.400-405
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• 2001