|
|
||||||||
University of Nebraska, Lincoln 68583-0908
Abstract
Mass selection for an index of increased postweaning average daily gain and decreased backfat thickness was practiced for five generations. Litter size and weight for 221 gilt litters, birth weight and nipple number for 2,242 piglets and weaning weight at 42 d of age for 2,111 pigs were recorded. Carcass measurements were taken on 331 pigs. Differences between means of the lines (select control) were regressed on cumulative selection differential of the index. These regression coefficients were negative (P > .10) for total number born, number born alive, number weaned per litter, nipple number and carcass backfat thickness. Coefficients were positive (P > .10) for individual pig and litter weights at birth and weaning and for the carcass traits of length, longissimus muscle area and percentage of ham and loin. Absolute values of realized genetic correlations of index with traits evaluated were all .35 or less except the correlation with carcass backfat, which was -.84. None of these was significant; therefore, index selection for lean growth should have little effect on litter size and weight but may have a beneficial effect on carcass backfat.
1 Published as Paper No. 6990 Journal Series., Nebraska Agric. Exp. Sta.
2 Present address: Univ. Hawaii, Hilo 96720.
4 Present address: Booneville, IA 50038.
This article has been cited by other articles:
![]() |
A. Rosendo, L. Canario, T. Druet, J. Gogue, and J. P. Bidanel Correlated responses of pre- and postweaning growth and backfat thickness to six generations of selection for ovulation rate or prenatal survival in French Large White pigs J Anim Sci, December 1, 2007; 85(12): 3209 - 3217. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. B. Petry, J. W. Holl, and R. K. Johnson Responses to 19 generations of litter size selection in the NE Index line. II. Growth and carcass responses estimated in pure line and crossbred litters J Anim Sci, July 1, 2004; 82(7): 1895 - 1902. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |