제주지역 랜드레이스, 요크셔, 두록 및 버크셔 품종에 대한 계절, 산차, 품종이 정액 품질에 미치는 영향과 경제형질 분석

Abstract

The livestock industry in Jeju Island has proliferated exponentially because of its best geographic and climatic conditions. The island because of its special geographical location, has impeded the influx of foreign animal diseases, and due to blessed natural condition of clean air, water and mild climate, maintains the best condition to produce high quality pork. The declaration of Jeju provincial government for the Swine Epidemic-Free (swine fever, foot and mouth disease, Aujeszky's disease) Zone in December 1999, and the Cattle Plague-Free (brucellosis, TB disease) Zone in December 2003 have enhanced the brand values of tangible and intangible animal products and have raised the stability in the livestock industry. The genetic improvement of breeding pig along with increaseing income is an important aspect for the livestock sector. To accomplish these objectives, Livestock Promotion Agency (LPA), Jeju Province established swine station in 1997. The LPA has produced genetically superior pigs and evaluated their breeding potential and supplied proven boars and liquid semen to the pig farms in Jeju Island. Performance test of breeding pig has been widely used as an important tool for the genetic improvement of breeding pig in the world's major pig producing countries. Performance testing for the breeding value has greatly contributed to pig industry in Jeju Island. The genetic evaluation through performance test of breeding pig has been an essential process in order to maximize the use of high-capacity breeding pigs. The present study was carried out to analyze the effects of season, parity and breed on the semen quality and the economics traits of Landrace, Yorkshire, Duroc and Berkshire, and to get the basic data for systematic selection and breeding of pigs. Studies comprised experiments for three topics and the results obtained in the study are summarized as follows: Experiment 1. Influence of breed and season on the semen quality of boar The main objective of this study was to investigate the phenotypic variability of the semen ejaculate volume and sperm motility in Berkshire, Duroc, Landrace and Yorkshire breeds and the effects of breed and seasonal variations. A total of 5,214 records for the semen quality data from LPA, Jeju Province were obtained and analysed using GLM procedure in SAS statistical package. A general linear model used in this analysis included two fixed effects of the month of year and breed, and one random error term. The results obtained in the study are summarized as follows: 1）All the fixed effects, breed and season on the semen quality included in the statistical model were significant (p〈0.01). 2) The range of least-squares means for the effect of month on the semen quality were 250.1∼314.1ml for volume of semen, 260.1∼337.7×106/ml for sperm concentration, 78,031.7∼86,484.9×106 for number of sperms per ejaculate and 83.6∼92.2% for motility. The volume of semen were the highest amount in winter and the least amount in summer, and their difference of least squares means was significant (p〈0.01). 3) The range of least-squares means for the effect of breed on the semen quality were 270.4∼305.9ml for volume of semen, 266.2∼299.7×106/ml for sperm concentration, 71,238.6∼90,153.6×106 for number of sperms per ejaculate and 86.7∼91.0% for motility. For the volume of semen, Landrace breed produces the highest amount of 305.9ml and the difference of amount between any other breed, Berkshire, Duroc or Yorkshire shows significancy (p〈0.01). 4) The simple correlation coefficients between the traits of semen quality were -011 between volume of semen and sperm concentration, 0.57 between volume of semen and number of sperms per ejaculate, 0.71 between sperm concentration and number of sperms per ejaculate, 0.38 between sperm concentration and motility, 0.25 between number of sperms per ejaculate and motility and -0.06 between volume of semen and motility. Experiment 2. Effect of season, parity and breed on the litter size of berkshire, duroc, landrace and yorkshire sows To estimate the effect of breed, season and parity on the litter size, Data for the litter size were collected on 14,778 farrowings from 2,252 sows of Berkshire, Duroc, Landrace and Yorkshire breeds between 2000 and 2014 at the LPA, Jeju Province. The pigs were divided into four groups (four seasons); Spring (March-May), Summer (June-August), Autumn (September-November) and Winter (December-February). The statistical model for the litter size included four fixed effects of year, season, parity, breed, and one random effect of sow within breed, and a random error term. The analysis of variance using GLM procedure, SAS, was used to test these effects on the litter size. The results obtained are summarized as follows: 1) All four fixed effects of year, season, parity, breed on the litter size of sows were significant (p〈0.01). 2) The range of estimates for the effect of year on the litter size were 9.4∼11.3 piglets. The litter size was the highest in 2010 but the lowest in 2013. 3) The least-squares means for the effect of season on the litter size were 10.44 in Spring, 10.66 in Summer, 10.14 in Autumn and 10.26 in Winter. The litter size was not significantly different between Autumn and Winter (p〉0.05). 4) The least-squares means for the effect of breed on the litter size were 8.9 in Berkshire, 9.9 in Duroc, 11.4 in Landrace and 11.3 in Yorkshire. The litter size was the highest in Landrace, but Berkshire breed showed the lowest value compared to other breeds. 5) The range of least-squares means for the effect of parity on the litter size were 9.3∼11.3 piglets from first through tenth parity. The litter size increased from first through fourth parity but decreased from fifth through tenth parity. Experiment 3. Fixed factor affecting economic traits in swine breeding stock To determine the factors affecting swine economic traits of final weight, eye muscle area, days to 90kg, daily weight gain, backfat thickness, and meat percentage the performance data were collected from 21,734 pigs of Berkshire, Duroc, Landrace and Yorkshire breeds which were performance-tested at the LPA, Jeju Province from 2000 to 2014. The growth performance records of swine breeding stock were analysed using a statistical model with five fixed effects of year, season, sex, parity, breed, a random effect of dam, a regression term of litter size, and a random error term. Analysis of variances using GLM procedure, SAS, were performed to test factors affecting the performance traits. The results obtained are summarized as follows: 1) All five fixed effects of year, season, sex, parity, breed and a regression term of litter size were significantly affecting the growth performance traits of breeding stock (p〈0.01). Results indicates that these fixed effects are the important factors in the genetic evaluation of breeding stock. 2) The regregation coefficients for the effect of litter size were estimated as -0.46g for final weight, 0.05㎠ for eye muscle area, 0.512 days for days to 90kg, -2.85g for daily weight gain, but for the backfat thickness and meat percentage there were no significantly of litter size (p〉0.05). 3) The range of least-squares means for the effect of year were 83.1∼ 125.0kg for final weight, 27.2∼31.8㎠ for eye muscle area, 536.3∼647.6g for daily weight gain and 10.3∼13.7㎜ for backfat thickness. 4) The range of least-squares means for the effect of season were 94.3∼ 98.9kg for final weight, 28.7∼29.2㎠ for eye muscle area, 585.6∼605.5g for daily weight gain, 12.2∼12.7㎜ for backfat thickness and 59.0∼ 59.4% for meat percentage. 5) The least-squares means for the effect of sex were 94.8kg for final weight, 29.70㎠ for eye muscle area, 157.8 days for days to 90kg, 577.0g for daily weight gain, 13.1㎜ for backfat thickness, 58.6% for meat percentage in female and 99.9kg for final weight, 28.3㎠ for eye muscle area, 152 days for days to 90kg, 610.0g for daily weight gain, 11.7㎜ for backfat thickness and 59.7% for meat percentage in male. 6) The range of least-squares means for the effect of parity were 90.6∼ 101.6kg for final weight, 28.7∼29.3㎠ for eye muscle area, 153.4∼157.4 days for days to 90kg, 578.7∼598.4g for daily weight gain, 12.2∼12.8㎜ for backfat thickness and 58.5∼59.5% for meat percentage. 7) The range of least-squares means for the effect of breed were 84.0∼ 103.8kg for final weight, 28.4∼29.7㎠ for eye muscle area, 151.5∼161.5 days for days to 90kg, 553.8∼613.0g for daily weight gain, 11.4∼14.0㎜ for backfat thickness and 57.5∼60.0% for meat percentage. 8) The partial correlation coefficients while controlling for the performance testing period were -0.31 between final weight and eye muscle area, -0.98 between final weight and days to 90kg, 0.31 between eye muscle area and days to 90kg, 0.99 between final weight and days to 90kg, -0.15 between backfat thickness and daily weight gain and -0.69 between backfat thickness and meat percentage.