• Journal of Animal Science and Technology
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• v.61 no.2
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• pp.109-109
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• 2019

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.196-196
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• 2022

• Korean Journal of Animal Reproduction
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• v.27 no.4
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• pp.281-285
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• 2003

This study was carried out to find out the changes on serum concentrations of estradiol-17$\beta$, progesterone in primiparous Duroc, Landrace and Yorkshire sows weaned at 7 or 21 days. Also, we compared the litter size at birth and weaning among the breeds weaned after lactation for 7 or 21 days. The estradiol-17$\beta$ concentrations among the breeds were 6.9∼8.8 pg/ml and 6.4∼8.8 pg/ml after lactation for 7 or 21 days, respectively. The progesterone concentrations ranged from 0.3 ng/ml to 1.6 ng/ml. Duroc sow showed higher progesterone concentration compared with Landrace and Yorkshire sows weaned after lactation for 7 or 21 days. Also, we found out that litter size at birth and weaning, respectively, did not show any differences between day 7 and day 21 of lactation. From the facts mentioned above, it was suggested that very early weaning systems could work with no apparent adverse effect on prolificacy.

• Korean Journal of Animal Reproduction
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• v.8 no.2
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• pp.92-96
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• 1984

This study was carried out ot examine the sex ratios of offspring in swine. The sex ratios were obtained on the basis of the data from 15,892 pigs produced by 1,728 litters of Landrace, Large Yorkshire, Hampshire and Duroc breeds at National Animal Breeding Institute from 1975 to 1980. The results obtained are summarized as follows: 1. The sex ratio of total offspring was 51.47% for male and significant at 5% level, and Landrace and Duroc breeds were 51.46% and 52.27% for male and significant at 5% level, respectively, but no significant difference between the breeds. 2. The sex ratio of offspring by years was 52.74% for male and significant at 5% level in 1979, but no significant difference for other years and between years. 3. The sex ratio of offspring by seasons were a little highly 51.65% and 51.25%, for male in spring and autumn, but no significant difference, respectively. 4. The sex ratio of offspring by parities were 52.65% and 55.81% for male in groups of the 3rd to 4th and the 5th to 6th parity, and significant difference at 5% and 1% level, respectively. 5. The sex ratio of offspring by groups of litter size was 52.65% for male in 1 to 6 heads group, and significant difference at 5% level, but no significant difference between groups of litter size.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.7
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• pp.1015-1018
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• 1999

Single trait mixed models have been dominantly utilized for genetic evaluation of the reproductive traits in swine. However employing multiple trait approach may lead to more accurate genetic evaluations. For 5 litter size and litter weight traits of Danish Landrace, genetic parameters were estimated with a multiple trait mixed model. The heritability estimates were 0.02, 0.03, 0.03, 0.05, and 0.07, respectively for litter size at birth, litter size born alive, litter weight at birth, litter size at weaning, and litter weight at weaning. Negative genetic correlations were all positive. The litter weight at birth showed genetic antagonism with litter size born alive (-0.65) and litter size at weaning (-0.31), but positive with litter size at birth (0.47) and litter weight at weaning (0.31). The estimates of environmental correlations were larger than their corresponding genetic correlation estimates except for those between litter weight at birth and the other four traits. This study recommends simultaneous selection for two or more traits with multivariate mixed models in order to improve overall economic response.

• Journal of Veterinary Clinics
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• v.19 no.2
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• pp.191-194
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• 2002

The nursing vocalization of domestic pigs(Landrace$\times$Yorkshire) was investigated with respect to common features. All vocalizations uttered during nursings in 5 sows at 5 days after farrowing were recorded and 305 grunts were processed in a spectrograph. The sow's repeated grunting during nursing can be regarded as a contact call and a signal of the mother to start and synchronize the suckling behavior of the piglets. Analysis in the time domain revealed the gross structure of the call, whereas in the frequency domain the fine structure of single grunts was investigated. Nursing interval, duration of nursing behavior, duration of grunt, grunt rate per 10 seconds, fundamental frequency, 1 formant, 2 formant, 3 formant, 4 formant and spectrum were investigated. The results showed that mean interval between the nursing following one another was 25, 4.6 min and duration of nursing behavior was 3.2 $\pm$ 0.7 min. Average duration of grunt was 203.9 $\pm$ 63.6 ms. The formant contours could be identified. The nursing behavior might be disturbed by the grunts of alien sow.

• Journal of Animal Science and Technology
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• v.62 no.1
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• pp.14-20
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• 2020

The goal of this study was to determine an effective interval of playing a nursing sound stimulus. One hundred forty four lactating multiparous sows (Landrace; parity range: 2 to 7) and their litters (Landrace × Yorkshire) were divided into 3 block (48 each), each of which was randomly assigned to one of the four treatment groups including control which had no call stimulus (n = 12 each). The call of nursing and suckling, plus a click sound, were used as a nursing sound stimulus that was played in the intervals of 35 min (T35), 40 min (T40) and 45 min (T45) right after the first parturition in each experimental group until the day of weaning. Nursing sound stimuli did not affect the sow feed intake and back fat thickness loss. No differences were detected among treatments in the percentages of sows returning to estrus within 5 days after weaning and sows without crushed piglets. However, the piglets' weaning weight and daily weight gain in T35 and T40 groups was greater (p < 0.01) than the controlled piglets. These results suggest that a nursing sound stimulus can improve the performance of suckling piglets, and that 35 or 40 min interval of playing a nursing sound could be the effective sound stimulus for nursing sows.

• Korean Journal of Agricultural Science
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• v.46 no.3
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• pp.417-426
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• 2019

This study was conducted to evaluate seasonal effects on production performance of lactation sows reared in two different environments in South Korea. A total of 76 sows ($Landrace{\times}Yorkshire$) from the Dankook University experimental farm and 120 sows ($Landrace{\times}Yorkshire$) from a commercial farm were collected. In the current study, reduced (p < 0.01) feed intake and energy intake during lactation were observed in warm season compared with cool season in both farms. Sows in cool season had higher backfat thickness at weaning but lower back fat loss (p < 0.01) than those in warm season. The weaning to estrus interval was lower (p < 0.01) in cool season than in warm season. Piglets weaned in warm season had lower (p < 0.01) body weight (BW), body weight gain (BWG), and average daily gain (ADG) at weaning than did those weaned in cool season on the Dankook University farm, whereas the reduction effect was only observed during 0 - 21 d on the commercial farm (p < 0.01). Moreover, piglets weaned in cool season had higher BW, BWG, and ADG (p < 0.05) on both farms. In conclusion, our results indicate that warm season had very negative effects on feed intake and production performance of lactating sows and piglets.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.1081-1093
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• 2023

This study aimed to compare meat quality traits between Berkshire and crossbreed (Landrace × Yorkshire × Duroc), and to investigate the relationship between meat quality traits and fatty acid composition. 20 Berkshire and 20 crossbreed pigs were used to compare pork loin quality and to determine the relationship between measured variables. 23 variables were measured including proximate composition, pH, drip loss and cooking loss, Warner-Bratzler shear force, and fatty acid composition. Berkshire had higher moisture content, pH, water-holding capacity, saturated fatty acids, and redness than the crossbreed pig (p < 0.05). The fat content and polyunsaturated fatty acid were low (p < 0.05) in Berkshire. Correlation analysis showed a negatively correlation between moisture and fat content, and a positively correlation between saturated fatty acid and fat content. Moreover, saturated fatty acid and polyunsaturated fatty acid were negatively correlated. As a result of factor analysis and partial least square regression, saturated fatty acid and polyunsaturated fatty acid were estimated to be the main factors affecting quality characteristics of pork. Pig breed is associated with differences in meat quality, and fatty acid composition can have an effect on meat quality parameters.

• Animal Bioscience
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• v.37 no.5
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• pp.807-816
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• 2024

Objective: This study aims to identify the significant regions and candidate genes of growth-related traits (adjusted backfat thickness [ABF], average daily gain [ADG], and days to 90 kg [DAYS90]) in Korean commercial GGP pig (Duroc, Landrace, and Yorkshire) populations. Methods: A genome-wide association study (GWAS) was performed using single-nucleotide polymorphism (SNP) markers for imputation to Illumina PorcineSNP60. The BayesB method was applied to calculate thresholds for the significance of SNP markers. The identified windows were considered significant if they explained ≥1% genetic variance. Results: A total of 28 window regions were related to genetic growth effects. Bayesian GWAS revealed 28 significant genetic regions including 52 informative SNPs associated with growth traits (ABF, ADG, DAYS90) in Duroc, Landrace, and Yorkshire pigs, with genetic variance ranging from 1.00% to 5.46%. Additionally, 14 candidate genes with previous functional validation were identified for these traits. Conclusion: The identified SNPs within these regions hold potential value for future marker-assisted or genomic selection in pig breeding programs. Consequently, they contribute to an improved understanding of genetic architecture and our ability to genetically enhance pigs. SNPs within the identified regions could prove valuable for future marker-assisted or genomic selection in pig breeding programs.