초록 ▼

Ⅳ. 연구개발결과
본 연구과제를 수행하여 얻은 결과는 다음과 같다. 제1세부과제는 돼지 사육형태(슬랏, 톱밥)와 성장단계별(자돈, 육성돈, 비육돈) 적정 사육면적 및 성장단계별(육성돈, 비육돈) 적정 사육규모를 제시코자 생산성적, 혈중 생화학성분, 스트레스호르몬 및 도체성적을 조사·분석하였다. 본 연구를 통해 사육밀도 증가에 따른 생산성적 감소와 면역력 저하, 생리적 변화가 야기됨을 밝혀내었으며, 이들 결과를 토대로 각 성장단계별, 사육형태별 적정 사육면적과 규모를 제시하였다.
제2세부과제는 우리나라 이유자돈사에 적합한

Ⅳ. 연구개발결과
본 연구과제를 수행하여 얻은 결과는 다음과 같다. 제1세부과제는 돼지 사육형태(슬랏, 톱밥)와 성장단계별(자돈, 육성돈, 비육돈) 적정 사육면적 및 성장단계별(육성돈, 비육돈) 적정 사육규모를 제시코자 생산성적, 혈중 생화학성분, 스트레스호르몬 및 도체성적을 조사·분석하였다. 본 연구를 통해 사육밀도 증가에 따른 생산성적 감소와 면역력 저하, 생리적 변화가 야기됨을 밝혀내었으며, 이들 결과를 토대로 각 성장단계별, 사육형태별 적정 사육면적과 규모를 제시하였다.
제2세부과제는 우리나라 이유자돈사에 적합한 환기방식의 제시와 더불어 온습도 변화, 공기속도 및 생산성과 자돈의 폐사율 분석을 통하여 효과를 평가하였다. 국내 이유자돈사에 적합한 환기방식은 측벽덕트입기와 측벽배기, 측벽상부입기와 지붕배기, 마지막으로 천장입기와 측벽배기방식을 제시하였다. 또한 복도와 같은 완충공간에 대한 분석 및 설계기준을 제시하였다.뿐만 아니라 이유자돈사의 환경을 통합적으로 모니터링 및 제어할 수 있는 환경관리장치를 개발하였다.
제1협동과제를 수행하여 얻은 결과는 다음과 같다. 임신돈 스톨을 개량하여 국내 소규모 농가에 적용 가능한 개량스톨을 고안하였다. 개량스톨을 통해 임신돈이 강건한 자돈을 생산하여 포유자돈의 일당증체량이 기존스톨에 비해 12% 이상 향상되고, 모돈의 재귀발정일이 약 17%감소하였다. 모돈의 평균산차를 4.0산에서 4.8산 이상으로 약 17% 증가시켰다. 또한, 후보돈의 적정 체중 및 일령에 관한 실험을 통해 초종부 체중 140∼150kg과 초종부 일령 220∼240일인 것으로 나타났다.
제2협동과제는 국내 소모성질병이 문제시 되는 25개소를 선정하여 질병발생 위험도를 분석하였고, 예방접종 개선 프로그램을 작성하였으며, 소모성 핵심 질병인 돼지써코바이러스병을 신속하게 진단할 수 있는 udPCR법을 개발하였다. 그리고 돼지 설사병의 치료효과를 높이기 위해 면역증강제를 제작하여 효능을 검정한 후 2종을 산업화하여 제품화하여 당초 계획한 연구내용을 달성하였다.

Abstract ▼

1. Title : Study on optimal stocking density and group size at the different growth stage of pig
Stocking density affects the growth performance and physiological responses of pigs. First study aimed to evaluate the optimum stocking density for improved growth performance and reduced environmenta

1. Title : Study on optimal stocking density and group size at the different growth stage of pig
Stocking density affects the growth performance and physiological responses of pigs. First study aimed to evaluate the optimum stocking density for improved growth performance and reduced environmental stress in pigs at different growth stages. A total of 1,590 crossbred (Landrace×Yorkshire×Duroc) pigs were housed on a slatted floor and assigned to one of four treatments for each growth stage (stage 1, 11 to 25 kg body weight; stage 2, 25 to 45 kg body weight; stage 3, 45 to 65 kg body weight; stage 4, 65 to 85 kg body weight; stage 5, 85 to 110 kg body weight) with 3 replicates per treatment. The average daily gain (ADG) decreased significantly with increased stocking density (P<0.01 or 0.001) for all growth stages except Stage 2 (P = 0.159). The differences in ADG between the lowest and highest stocking densities were 110.7%, 113.5%, 110.3%, 114.8%, and 117.0% for Stages 1 to 5, respectively. ADFI was not significantly affected by stocking density at Stages 1 to 4; however, at Stage 5 there was a linear effect of stocking density on ADFI(P = 0.001). The FCR showed results similar to ADG. Serum IgG was not influenced by stocking density, but serum cortisol increased as stocking density increased. The highest serum cortisol level was observed in T3 at Stages 2 to 5 (linear relations 0.022, 0.001, and 0.103 in Stages 2, 4, and 5, respectively; quadratic relations 0.011, 0.003, and 0.028 in Stages 2 to 4, respectively). Proinflammatory cytokines increased in a significant linear manner at every growth stage in pigs reared at a high stocking density (P<0.05), although some cytokines showed only a marginal increase (P<0.1) or no significant difference(TNF-α in stages 1 and 3 and IL-6 in stages 2 to 4; P > 0.1). It is concluded that high stocking density induces environmental stress and a cellular immune response resulting in retarded growth performance. It is suggested that the optimal stocking density for the different growth stages of pigs are as follows: 0.24, 0.44, 0.64, 0.78, and 0.80 m²/pig for body weights of 11 to 25, 25 to 45, 45 to 65, 65 to 85, and 85 to 115 kg, respectively.
Second study determined the effects of space allowance on the performance, carcass grade and physiological variables of pigs reared in a sawdust fermentative pigsty. A total of 699 crossbred (Landrace×Yorkshire×Duroc) pigs were housed in a sawdust fermentative pigsty and assigned to one of three treatments at different growth stages (early grower pigs weighing 15 to 40 kg, EGP; late grower pigs weighing 40 to 75 kg, LGP; finisher pigs weighed 75 to 110 kg, FP) with 3 replicates. The three space allowances for each growth stage were as follows: 0.40, 0.55, and 0.70 m²/head for EGP, 0.55, 0.70, and 0.85m²/head for LGP, and 0.85, 1.00, and 1.15m²/head for FP. The feed intake in EGP was significantly decreased with increasing stocking density. In LGP, the ADG of pigs reared at a high stocking density decreased linearly, whereas the FCR increased significantly. The final body weight, ADG, and feed intake in FP were lower with the small space allowance than the large space allowance. The carcass weight and backfat thickness were significantly higher with an increasing space allowance. The serum immunoglobulin G (IgG) levels declined significantly with increasing stocking density in all of the growth stages. The results of this study suggest that the space allowance for maximizing the growth performance and immune response of pigs in a sawdust fermentative pigsty is 0.55,0.70, and 1.00 m²/pig for the body weight ranges of 15 to 40 kg, 40 to 75 kg, and 75 to 110 kg, respectively.
Third study determined the effects of group size on the performance, carcass grade and physiological variables of pigs reared in a sawdust fermentative pigsty. A total of 180 crossbred (Landrace×Yorkshire×Duroc) pigs were assigned to one of two treatments (20 heads/pen or 40 heads/pen) at different growth stages (grower pigs weighing 30 to 60 kg; finisher pigs weighing 60 to 100 kg) with 3 replicates. Growth performances were not affected by group size. And no significant difference in carcass characteristic between 20 and 40 heads/pen group in finisher pigs. The serum tumor necrosis factor-alpha (TNF-α) level was significantly lower in 40 heads/pen than 20 heads/pen(P<0.01). In conclusion, if all pigs could freely access feeders and nipples, and space allowances for pig are equal, this study suggest that the group size within a pen do not affect the growth performance.
2. Title : Development of feeding technology and ventilation systems to increase the rate of rearing of weaned pigs
The 1st year study was conducted to give the basic information for ventilation systems of weaned pig house to establish the acceptable ventilation system in Korea. A total of 11 farms were surveyed in this study and 1 more farm in each province was regionally selected. The general information, inlet and outlet ventilation system, alley in house, space allowance of weaned pigs and manure management were surveyed. Space allowance of weaned pig in 82% of surveyed farms met the legal standard. Side wall inlet and outlet ventilation system were 82% and 73% of surveyed farms, respectively. Moreover, 73% farms have alley in the pig house to control temperature of inlet air. In this survey, both planar slot and circular duct inlet system and side wall fan outlet system could be a favorable ventilation system in weaned pig house. The 2nd year study was conducted to collect basic data about the effect of buffering zone installation in weaned pig house. Buffering zone was installed either inside or outside of pig house to compare changes of temperature, humidity and air velocity of pig room. The body weight and mortality of weaned pigs in house with buffering zone was also measured. There was no difference in temperature, humidity and air velocity between inside and outside buffering zone. Mortality of weaned pig in house with buffering zone was drastically decreased compare to pigs in house without buffering zone that could be useful to maintain constant temperature and decrease mortality. The ICT based environment control device applicable in piglet house was newly developed. This device could be successfully operated to maintain stable temperature with automatic monitoring of temperature, humidity, fan, heater, drinker and electric power status.
3. Title : Development of sow feeding system and environment for improving MSY
The objective of the present study was to investigate the effects of age and weight at puberty, feeding style and energy levels on reproductive performance of swine. At the first experiment, a total of 68 crossbred sows (Landrace × Yorkshire) were allotted to one of three treatments over six consecutive parities. During the first parity, sows were assigned to three weight groups at the first puberty (light: 130 to 140 kg, Medium: 140-150 kg and heavy: 150 to 160 kg). At mating and d 109 gestation, back-fat thickness were greater (p<0.05) in heavy sows at first, second and third parities. Heavy sows lost more backfat (p<0.05) than light sows in lactation time. Feed intake and weaning-to-estrus interval of sows showed no difference among the groups. Weaned piglets body weight was greater in medium weight sows than heavy sows. At the second experiment, a total of 86 crossbred sows (Landrace × Yorkshire) were allotted to one of three treatments over six consecutive parities. During the first parity, sows were assigned to three age groups at the first puberty (A1: <220 d, A2: 220 to 240 d and A3: >240 d). At mating and d 109 gestation, back-fat thickness were greater (p<0.05) in A3 group sows at first, second and third parities. Sows in A3 and A2 groups lost more backfat (p<0.05) than sows in A1 group in lactation time. Feed intake and weaning-to-estrus interval of sows showed no difference among the groups. At the third experiment, a total of 32 crossbred sows (Landrace × Yorkshire) were allotted to two treatments over six consecutive parities. Sows were assigned to two kinds of stalls: Common commercial Stalls and free access stalls (FAS).At mating, weaning and d 109 gestation, back-fat thickness were similar between the groups. Sows in FAS treatment were heavier at mating time in the sixth parity and they tended to loss less weight at lactating in first and second parities. Feed intake of sows in FAS group was greater at the third parity (p<0.05). At weaning, back-fat thickness changes were lesser (p<0.05) in group housed sows than that of sows in stalls. The number of piglets at weaning, growth rate and average daily gain were greater (p<0.05) in group housed sows than that of sows in stalls. During gestation, walking duration was more (p<0.05) in group housed sows. Group housed sows had lesser (p<0.05) farrowing duration and greater (p<0.05) eating time than that of sows in stalls. Result obtained in present study indicated that sows with ≥20 mm back-fat thickness at 107 days had better reproductive performance. Additionally, group housing of sows during last five week of gestation improved the performance and behavior and reproductive efficiency of sows. The fourth experiment, a total of 40 crossbred developers sows (Landrace × Yorkshire) were allotted to two treatments over six consecutive parities. Developer sows were assigned to two different levels of energy (High: 3300 kcal/kg, Low: 3200 kcal/kg). At d 109 of gestation, body weight of developer sows were greater (p<0.05) with high energy diet. Gestation body weight gain, lactation backfat loss, age at first estrus and age at AI tended to be greater in sows in high energy diet group. Initial litter weight was significantly greater in sows with higher energy level in the diet however, the final litter weight ant weaning was similar. The information gained in the present series of experiments shows that the best age of gilts for mating is 220 to 240 days old with an average weight of 140 to 150 kg. Sows in FAS groups showed a relatively better performance than sows in common stalls. The low energy diet in developer sows diet showed a similar final litter performance compared with the high energy diet, however, the initial litter weight of low energy diet was less than sows in high energy group. Therefore it can be recommended to use the low energy diet in developer sows.
4. Title : Development of control and prevention program for pig wasting diseases
In this study, we investigated the outbreak pattern of porcine wasting diseases that caused a tremendous economic losses in Korean pig production, and developed a control and management program for the wasting diseases. Results of disease monitoring in Korean pig farms were showed that majority of the tested farms suffered with enteric diseases, such as colibacillosis and rota virus infection in suckling-weaned periods, and porcine respiratory disease complex (PRDC) in growing-fattening periods. For the rapid and reliable diagnosis for major pig wasting pathogen, porcine circovirus 2 (PCV2), we developed a noble direct polymerase chain reaction (dPCR) and loop-mediated isothermal amplification assay (LAMP). The dPCR and LAMP assay were confirmed to be useful for the rapid detection of PCV2 in various field samples and expected to be a alternative method for convention molecular diagnostic assay. An immue-enhancing management program using commercial immune-enhancing products were confirmed to be effective for preventing enteric diseases in suckling piglets in field trials. A basic vaccination program was documented for current Korean pig farms, which was adjusted to suit the current situation of pig disease outbreak patterns in Korea. And we selected some effective antibiotics for Salmonella and E. coli isolated from tested farms and recommended for the treatment of the bacterial enteritis.