賴永裕 李世昌 張秀鑾 黃鈺嘉 吳明哲
GENERATION INTERVAL OF MEAT PRODUCTION IN BREED REGISTRATION OF PIGS
Y. Y. Lai, S. C. Lee, H. L. Chang, Y. C. Huang and M. C. Wu
Livestock Research Institute, Council of Agriculture, Executive Yuan
Registration on meat production of growing pigs must be tested at the Boar Test Station and the pig was granted from the growth performance test. A total of 11,812 head of granted pigs with registration on meat production was analyzed with their birth dates from 1983/1/1 to 2003/3/6 and there were 5,643 head of Duroc (D), 4,110 head of Landrace (L), 2,014 head of Yorkshire (Y) and 45 head of Hampshire (H). They were progeny of 2,897 and 6,684 blood registered boars and sows, respectively. Blood registered boar or sow can be proved as meat registered breeding stock when three of the corresponding progeny receiving meat registration from the Test Station. However, the three progeny must come from three different litters either from paternal half siblings or maternal half siblings. There were 999 boars and 139 sows having the progeny proof on meat production. Generation interval was then calculated from both birth dates between parent and offspring. When paternal siblings used, the mean generation interval were 809, 815, 888 and 758 days in D, L, Y and H boar, respectively. The corresponding intervals were 1,332, 1,472 and 1,506 days in D, L and Y sows, respectively. None of H sows received meat registration. Results concluded that paternal siblings for meat registration in D, L and Y boars were 1.5 years lesser than that of maternal siblings. However, there were still cases of maternal siblings with a generation interval of 2 years or less and were 669, 704 and 638 day in D, L and Y sows, respectively. In paternal siblings, the corresponding interval could be even shorter and less than one year, which were 346, 337 and 350 days of generation interval in D, L and Y breed, respectively. It confirmed that one year one generation on meat production via mass selection program could be done.
Key words: Registration, Growth, Selection.