• Asian-Australasian Journal of Animal Sciences
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• v.17 no.9
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• pp.1223-1226
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• 2004

Previously candidate gene approach revealed estrogen receptor (ESR) locus was associated with increased litter size. In this study, PvuII polymorphisms of ESR gene was detected by PCR-RFLP, and ESR locus was evaluated for its association with reproductive tracts components in the Large $White{\times}Meishan$ ($LW{\times}M$) F2 offspring. Ninety seven gilts with reproductive tracts components records and 136 offspring with performance traits records were genotyped and the results were used to estimate allele substitution effects. The results showed that two alleles (A and B) were identified, and 121 bp fragments were observed for the AA genotype and 65 bp and 56 bp fragments for the BB genotype; the length of uterine body (LUB) of BB gilts were significantly shorter than AA gilts', the additive effect was -1.762 cm; the uterine weight (UW) of AB gilts were significantly lighter than AA gilts' with the additive effect -18.058 g; no significant associations of ESR alleles with ovulation rate (OR), length of uterine horn (LUH), length of uterine cervix (LUC), weight of two ovaries (OW), volume of uterine lumen (VUL), length of oviduct (LO) were observed. BB genotypes gilts need significantly less days to 100 kg ($D_{100kg}$) than AA genotypes (p<0.01), the additive effect was per copy of B allele. Allele B is also favorable for average daily gain (ADG), with additive effect 0.015 kg/d (p<0.05). There was no difference between genotypes for backfat thickness at the 13th rib (SF13), loin meat height (ELMH), and loin meat percentage was estimated (ELMP), individual birth weight (IBW) and teat number (TN).

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.249-255
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• 2003

These studies were performed to improve the reproductive efficiency of gilts and we investigated the effects of puberty periods, first mating time and backfat thickness and will adapt to these results for early selection of excellent gilts. The main results were as follows; 1. First heats on birth season were showed 194.14 day, 163.25 day, 160.25 day and 157.92 day at birth of spring, summer, autumn and winter, respectively and birth of spring was significantly latest among other seasons (p<0.01). 2. First service on birth season were revealed 222.05 day in spring, 193.00 day in summer, 199.20 day in autumn and 190.11 day in winter. birth of spring was significantly latest among others (p<0.01). 3. First heat period of cadidated gilt had 13∼16 mm backfat thickness was 180.32 day, 171.24 day in 17∼20 mm and 162.20 day in 21∼23 mm and was showed delay in thin backfat gilts. There was no differences among backfat thickness. 4. First service of cadidate gilt had 13∼16mm backfat thickness was 211.12 day, 202.43 day in 17∼20 mm and 195.43 day in 21∼23 mm and was showed delay in thin backfat gilts. There was no differences among backfat thickness. 5. The litter size were 9.64 in gilts under 160 day of first heat, 10.14 in 161∼180 day, 9.56 in 181∼200 day and 9.13 in over 201 day. There showed the largest litter size in 161∼180 day of first heat but was no differences. 6. The litter size in gilts under 180 day of first service was 9.13, 9.75 in 181∼200 day, 10.13 in 201∼220 day and 9.45 in over 221 day. There showed the largest litter size in 201∼220 day of first service but was no differences. 7. The litter size of gilt had 13∼16 mm backfat thickness on first service was 9.33, 9.81 in 17∼20 mm and 10.17 in 21∼23 mm and was showed delay in thin backfat gilts. There was no differences among backfat thickness.

• Journal of Embryo Transfer
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• v.23 no.3
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• pp.217-222
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• 2008

In previous studies, we reported that sow which was transferred OPS-freezing embryos not able to deliver a piglet (Kim et al, 2004). This study was conducted to investigate a possibility of gilt as recipients which produce piglets after transfer of OPS-freezing embryos. All transferred embryos were prepared by in vitro production (IVP) system. In vitro culture (IVC) medium used glucose-free NCSU23 supplemented with 5mM sodium pyruvate, 0.5 mM sodium lactate and 4 mg/ml bovine serum albumin for 2 days at $39^{\circ}C$. From day 3 of IVC, 10% fetal bovine serum albumin was added to the culture medium. In preparing of freezing embryos, embryos were treated with 7.5 $\mu g/ml$ cytochalasin-B for 30 min and centrifuged at $13,000{\times}g$ for 13 min. And then, embryos were exposed sequentially to an ethylene glycol (EG) solution, aspirated into open pulled straw (OPS), and plunged or thawed into the liquid nitrogen. In embryo transfer (ET), we used two kinds of type (surgical method vs. non-surgical method). In surgical method of embryo transfer, $55\sim65$ embryo were transferred in both uterine horn of two recipient gilts by plastic straw. Non-surgical method which is like artificial insemination was performed on three gilts. Each 140 frozen embryos were transferred to two gilts and 40 fresh embryos to one gilt. Pregnancy establishment was shown one recipient at 45 days after ET. However, the one recipient was also aborted at 58 days after ET. These results suggest that gilts can be considered as a candidate of recipients for OPS-freezing embryo transfer.

• Journal of Embryo Transfer
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• v.18 no.3
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• pp.257-262
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• 2003

These studies were performed to improve the reproductive efficiency of gilts and we investigated the effects of nursing periods after parturition and backfat thickness will adapt to these results for early selection of excellent gilts. The main results were as follows; 1. The backfat thickness in sows nursing for 17∼21 days was 19.19 mm, and 16.52 mm in 22∼26 days and longer nursing period affected significantly the backfat thinner (p<0.01). 2. The recurrence of estrus in sows nursing for 17∼21 days was 5.76 day and 5.62 day in 22∼26 days and there was no difference between nursing periods. 3. The recurrence of estrus in sows had 13∼16 mm backfat thickness was 5.69 day, 5.67 day in 17∼20 mm and 5.75 day in 21∼23 mm and there was no difference among backfat thickness. 4. The concentration of plasma estradiol were 28.49 pg/$m\ell$ in parturition, 12.39 pg/$m\ell$ in weaning and 16.52 pg/$m\ell$ in return of estrous. The concentration ot plasma progesterone were 1.50 ng/$m\ell$ in parturition, 0.69 ng/$m\ell$ in weaning and 0.94 ng/$m\ell$ in return of estrous. The concentration of plasma cortisol were 57.74 ng/$m\ell$ in parturition, 43.01 ng/$m\ell$ in weaning and 47.89 ng/$m\ell$ in return of estrous. There showed the highest level of estradiol, progesterone and cortisol in parturition.