Impact of harvest weight on the relative growth performance and carcass characteristics of progeny of two swine sire lines

Abstract Text:  The relative performance of the progeny of 2 sire lines was evaluated with a total of 2784 pigs in a commercial wean-to-finish facility to determine the impact of sire line and gender on growth performance and carcass characteristics of pigs sent for harvest at 4 harvest weights (111, 125, 138, and 145 kg).  Separate studies were conducted within each harvest weight (HW); each study used a RCBD with a 2 x 2 factorial arrangement of treatments: 1) Sire Line (A vs. B) and 2) Gender (Barrows vs. Gilts).  Pigs were housed from weaning (6.7 ± 0.31 kg BW) to the respective HW in groups of 29 with ad libitum access to feed and water.  Within each HW, pigs were sent for harvest in 4 groups over a 5-wk period at a commercial facility and standard carcass grading measures were collected.  Final pen mean BW for the 4 studies were 111.1 ± 2.95, 122.0 ± 2.23; 134.5 ± 2.56, and 141.6 ± 2.63 kg, respectively.  Barrows had greater (P < 0.05) overall ADG and ADFI, and 10^th rib backfat depth but similar (P > 0.05) overall G: F than gilts at all HW.  The two sire lines had similar (P > 0.05) ADG at the 2 lighter HW; Line A grew faster (P = 0.004) than Line B at HW of 138 kg (22.7 g/d) and tended to grow faster (P = 0.09) at HW of 145 kg (13.6 g/d).  Line A had lower (P < 0.05) ADFI than Line B at the 2 lighter HW [1.83 vs. 1.87 kg/d (SEM 0.028) at 111 kg; 1.92 vs. 1.97 kg/d (SEM 0.035) at 125 kg] but at the 2 heavier HW there was no difference (P > 0.05) between the lines for ADFI.  Line A had greater (P < 0.05) G:F than Line B at all HW except at 138 kg HW, where there was no difference (P > 0.05) between the lines.  Carcass yield was lower (P < 0.05) for Line A than B at the 2 heavier HW [74.8 vs. 75.2 % (SEM 0.15) at 138 kg HW; 74.8 vs. 75.5 % (SEM 0.10) at 145 kg HW]; however, at the 2 lighter HW the lines had similar (P > 0.05) carcass yield.  Line A had lower (P < 0.05) 10^th rib backfat depth but similar (P > 0.05) Longissimusmuscle depth at all HW.  These results suggest that when evaluating sire lines for growth and carcass characteristics the final BW can influence the difference between the lines.

Keywords:

Pig, sire line, harvest weight