• Korean Journal of Animal Reproduction
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• v.17 no.1
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• pp.35-41
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• 1993

The study was conducted to investigate the effects on environmental factors on the reproductive performance of Korean native cattle based on the data from 13, 588 records which were surveyed from 1983 to 1992. The results obtained in this study are as follows; 1. Mean performaces of the reproductive traits were 510.2days for the age at 1st service, 525.0days for the age at 1st conception, 808.7 days for the age at 1st calving, 102.5 days for the days to 1st conception postpartum and 388.6 days of the calving inverval. The cows of Chunbuk province were tended to be bred and calved at younger age and showed shorter calving interval than those of other provinces. 2. The effect of birth year was significant for the reproductive performances, especially, in 1986~1987 when the cattle prices dropped sharply and reproductive performances were poor. 3. The times of 1st service and 1st conception of heifers calved in spring tended to be delayed. Days to 1st conception postpartum, calving interval and days to 1st service postpartum of cows calved in fall were shorter than other calving season's cows. 4. Days to 1st conception postpartum, calving interval and days to 1st service postpartum of cow's were shortened and gestation length was prolonged as the number of parity increases.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.489-493
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• 2003

Reproductive traits of sows are determined chiefly by the genetic background of the dam herself. Whether the breed of the serviced boars also contributes is not yet clear. A total of 8,946 litters of Landrace (L) sows from 68 farms were examined. Of these, 876, 1,260, and 6,810 litters were produced from natural mating with L, Yorkshire (Y), and Duroc (D) breeds, respectively. The birth litter size (BLS), weaning litter size (WLS), live born piglets (LBP), and survival rate % (SR), of every litter were recorded. A general linear-model procedure was followed to estimate the effects of boars' breed (B), parity (P) and B${\times}$P interaction on the reproductive traits of the sows. Results show that BLS, WLS, and LBP were all significantly (p<0.001) affected by B and P. SR% was significantly influenced by B but not by P. L sows crossbred with Y or purebred with L produced litters with higher BLS, WLS, and LBP values than those bred with D. Pure L breeding yielded litters with lower SR% than did crossbreeding with D, while the difference between SR% due to LY and that due to LD crossbreeding was not significant. The interaction of B with P was significant with respect to BLS, WLS, and LBP (p<0.001), but not SR%. No significant B effect on reproductive traits was measured in sows at their first parity; but at latter parities, LL or LY produced litters with similarly high BLS, WLS and LBP, which values were all significantly greater than those of LD litters. The breed of boar evidently affected the subsequent reproductive performance of L sows and this effect may be further manipulated by the parity effect. Breed differences in semen quality and the success of fetus development with different interactions of the genetic background with the uterus function of the sow that may contribute to these effects are discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.12
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• pp.1680-1685
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• 2002

Reproductive data collected from more than 20,000 Japanese Black cows of Hyogo and Shimane Prefectures were analyzed. Averages of age at first calving, gestation length, days open and calving interval were 25.1 mo, 289 d, 112 d and 401 d, respectively. Variance components were obtained by REML procedure and the heritability estimate of age at first calving was 0.22. In gestation length the heritability estimate was 0.40 and no permanent environmental effect was estimated. Estimated variance components of calving interval were similar to those of days open and the heritability and repeatability of calving interval were 0.05 and 0.09, respectively. Random farm effects accounted for approximately 10% of phenotypic variations in all traits. Genetic and farm correlations between age at first calving and calving interval were 0.27 and 0.39, respectively. It was found that temporary environment was an important source of variation for calving intervals of Japanese Black.

• Reproductive and Developmental Biology
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• v.34 no.1
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• pp.27-32
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• 2010

This study was conducted to estimate the effect of the breed, sire-breeds, farrowing year, farrowing season and parity on number of born alive (NBA), number of weaning (NW) and survival rates of weaning (SRW) in swine. The data were obtained from 46,704 litters of the Landrace, Yorkshire, Duroc and Cross breed farrowed from 1996 to 2005 at 142 GP are registered in Korean Animal Improvement Association (KAIA). There was highly significant effect of breed, sire breed, farrowing year, farrowing season and parity on NBA, NW, SRW (p<0.01). The result of this study could be available to genetic improvement of reproductive traits as a basic reference in Korean pig industry. To achieve the more effective improvement of reproductive traits, additional research such as genetic parameter evaluation should be performed.

• 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 Animal Science and Technology
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• v.50 no.4
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• pp.457-464
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• 2008

Heritability and genetic correlation for reproductive traits in Yorkshire pig breed were estimated using Bayesian method via Gibbs sampling. The data set consisted of 9,609 reproductive records at pig breeding farm in Korea. For estimating those parameters using Gibbs sampling, 5,000 cycles of ‘burn-in’ period were discarded among a total of 55,000 samples. Out of the remaining 50,000 samples, 5,000 estimates by each parameter were retained and used for analyses to avoid any correlation among adjacent samples. The reproductive trait considered in this study were total number of born piglets(TNB) and estimated by two different models. The estimated heritability and permanent environmental effect using Gibbs sampler were 0.12±0.020 and 10.9±1.63, respectively. Estimated genetic correlations considered parities as different traits were distributed from 0.99 to －0.13. Such results indicated that reproductive traits for sows should be considered as different traits.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.2
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• pp.179-183
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• 2002

The fragment in intron I of FSH-${\beta}$ gene was amplified by PCR. According to the polymorphism, we analyzed the distribution of FSH-${\beta}$ retroposon in different pig breeds; its inheritance pattern in Large White${\times}$Meishan reference family; and the association of FSH-${\beta}$ retroposon with litter size, female reproductive organs measurement, ultrasonic backfat and other traits. The results showed that almost each Chinese indigenous pig had the retroposon, while foreign pig breeds rarely had; the frequencies of porcine FSH-${\beta}$ retroposon were strongly associated with breeds (p<0.01); the pattern of inheritance was consistent with Mendelian fashion; total number born (TNB) and number born alive (NBA) were increased per FSH-${\beta}$ retroposon (p<0.01) with additive effects of 1.2-1.8 and 1.4-1.8 pigs/litter, respectively; between the FSH-${\beta}$ retroposon carriers and non-carriers, there was an insignificant difference in the measurement of female reproductive organs, body weight at birth, backfat thickness, loin meat height, lean meat percentage, teat number, days to 100 kg, and average daily gain.

• Journal of Animal Reproduction and Biotechnology
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• v.38 no.3
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• pp.151-157
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• 2023

Background: The potential impact of aqueous extracts from Psidium guajava leaves on the reproductive system of female rabbits was evaluated. Methods: Twenty-eight rabbits, aged five to six months were utilized. Rabbits were divided into four groups and were randomly assigned to receive one of the following oral doses of the guava leaf extracts: 0 (control group), 10, 20, or 30 mg/kg of body weight. After a treatment period of 30 days, blood was collected via jugular venipunture and the serum was extracted for the assessment of serum biochemical traits levels. The females were bred and monitored throughout their pregnancy to ascertain reproductive outcomes. Results: The results indicated that the guava leaf extract significantly increased the body weight of the rabbits during both pre- and post-pregnancy compared to the control group (p < 0.05). The litter size at three weeks post-birth, prolificity rate, FSH, LH, and protein levels were notably higher (p < 0.05) at a dose of 20 mg/kg of body weight. The viability rate three weeks post-birth increased with escalating extract doses, and the highest values were observed at doses of 20 and 30 mg/kg of body weight (p < 0.05). Conclusions: This study demonstrated that, the aqueous extract of guava leaves appears to stimulate the production of FSH, LH and enhance body weight, prolificity, and pregnancy outcomes in mammals. As such, it is suggested that a dose of 20 mg/kg body weight could be beneficial in improving the reproductive performance of female.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.51 no.2
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• pp.163-168
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• 2006

Improvement of crop yield can be achieved through understanding genetic variation in reproductive characters and its impact on yield components. The present study was performed to evaluate genetic diversity for reproductive growth characters in exotic germplasm resources and to determine the relationships between developmental and growth periods with yield and yield components in soybean cultivar groups. For phenotypic evaluation such as reproductive and agronomic traits, a total of 80 indigenous and exotic soybean cultivars collected from four different geographical regions (China, Japan, Korea, and Vietnam) were grown from May to November of 2003 at the Seoul National University Farm, Suwon, Korea ($127^{\circ}02'E$ longitude, $37^{\circ}26'N$ latitude). Most of all the characters exhibited wide range of phenotypic variation, of which pod number, seed number, and plant yield showed greater range as compared to other characters. Korean cultivar groups showed greater diversity than the other cultivar groups in seven characters. Correlation analysis showed that days to flowering (DTF) and days to maturity (DTM) had close association with agronomic traits as well as yield and yield components. Both DTF and DTM had positive correlation with the other characters except one hundred seed weight. Stepwise multiple linear regression revealed that seed and pod number were identified as being significant for plant yield. The results in this study indicated wide variation in agronomic traits including DTF and DTM, suggesting the valuable genetic resources in a soybean breeding program.

• Journal of Embryo Transfer
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• v.9 no.1
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• pp.49-52
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• 1994

This study was carried out to compare farrowing rate and litter traits for European and American lines with boar sperm frozen in straws. Farrowing rate, litter size and mean pig weght at birth and 21 days were investigated. A total of 36 gilts Landrace, Large white and Duroc were investigated at the Chungnam Provincial Animal Breeding Station. We obtained higher farrowing rate and litter traits for European line boars compared to American line boars.