Abstract
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.
종빈돈의 번식효율 증진을 위해 후보종빈돈의 성성숙일령, 첫교배일령 및 등지방 두께 등이 번식능력에 영향을 미치는 요인을 조사$.$분석하여 우수한 후보종빈돈의 조기선발에 활용코자 수행한 결과는 다음과 같다. 1. 출생계절별 첫발정일령 및 첫수정일령은 봄에 출생한 후보종빈돈은 194.14일 및 222.05일, 여름에 출생한 후보종빈돈은 163.25일 및 193.00일, 가을에 출생한 후보종빈돈은 160.25일 및 199.20일, 겨울에 출생한 후보종빈돈은 159.72일 및 190.11일로 봄에 출생한 후보종빈돈의 첫발정일령이 겨울, 가을, 여름에 출생한 후보종빈돈보다 유의적으로 늦게 나타났다(P< 0.01). 2. 등지방두께가 13∼16mm인 후보종빈돈의 첫발정일은 180.32일, 17∼20mm인 후보종빈돈은 171.24일, 21∼23mm인 후보종빈돈은 162.20일로 등지방두께가 얇을수록 첫발정일령이 지연되었으나 유의적인 차이는 인정되지 않았다. 3. 등지방두께가 13∼16mm인 후보종빈돈의 첫수정일령은 211.12일, 17∼20mm인 후보종빈돈은 202.43일, 21∼23mm인 후보종빈돈은 195.43일로 등지방 두께가 얇을수록 첫수정일령이 지연되었으나 유의적인 차이는 없었다. 4. 첫발정일령이 160일령 이하일 때에 산자수는 9.64두였으며, 161∼180일렬인 경우 10.14두, 181∼200일령인 경우 9.56두, 201일령이상인 경우 9.13두로 첫발정일령이 161∼180일이었을 때가 산자수가 가장 많았으나 유의적인 차이는 없었다. 5. 첫수정일령이 180일령 이하일 때에 산자수는 9.13두였으며, 181∼200일령인 경우 9.75두, 201∼220일령인 경우 10.13두, 221일령 이상인 경우 9.45두로 첫수정일령이 201∼220일령이었을때가 산자수가 가장 많았으나 유의적인 차이는 없었다. 6. 첫수정시 등지방두께가 13∼16mm일 때에 산자수는 9.33두였으며, 17∼20mm인 경우 9.81두, 21∼20mm인 경우 10.17두로 첫수정시 등 지방두께가 21∼23mm이었을 때가 산자수가 가장 많았으나 유의적인 차이는 없었다.
