Evaluation of large White and Duroc boars as terminal sires under two different feeding regimes

Abstract

Large White and Duroc semen was used to form a three-breed cross from Large White x Norwegian Landrace dams. A pair of sibs from each litter was fed ad libitum and a further pair on a time-based scale at the Meat and Livestock Commission testing station at Stirling, Scotland. A total of 241 litters was tested. At the end of testing the pigs were slaughtered and standard carcass measurements were made. One side of the carcass of each of a sample of 60 pigs was fully dissected. The Duroc progeny grew faster and had better food conversion efficiency than the Large White progeny when fed ad libitum but there was no difference between the breeds when feeding was restricted. The Large White progeny produced a better trimming yield and were slightly longer. There was no significant difference in fat depths. The proportions of lean, fat and bone tissues did not differ greatly between the breeds although the Large White progeny had slightly more lean tissue and the Duroc progeny were more heavily boned and had more intermuscular fat. The Duroc terminal sires gave an economic advantage of £1·70 per pig when fed ad libitum but a loss of £0·35 when fed to a restricted scale. This was primarily due to the superior growth rate and food conversion efficiency of the Duroc progeny when fed ad libitum.

Evaluation of the Duroc in comparison with the Landrace and Large White as a terminal sire of crossbred pigs slaughtered at 85 kg liveweight

“…On an ad libitum feeding regimen, however, Duroc crosses grew faster (81 g/day) than Large White crosses and this was mainly the result of a higher voluntary feed intake (190 g/day). In a more recent investigation (Simpson et al 1987), which was an extension of that of Sutherland et al (1984) to evaluate more sires, the result agreed with those of the previous study.…”

“…Other studies where restricted feeding was adopted, have reported a similar effect (Madsen et al 1983;Sutherland et al 1984;Sigvardsson & Andersson 1985) but in some the breed difference, as in the present analysis of farm data, was not statistically significant (McGloughlin et al 1986;Simpson et al 1987). Differences in killing-out percentage in favour )f Duroc crosses over those sired by Large White or Landrace boars have also been recorded on ad ribitumfeeding, but they have generally been smaller than obtained on restricted feeding and not statistically significant (Sutherland et al 1984;Simpsonetal.1987).…”

“…Sutherland et al (1984), however, found larger eye muscle areas in cross-section in Duroc crossbreds when they were fed to scale and this was also observed in the present restricted feeding trial. However, this effect Was not observed in the extension of the study of Sutherland et al (1984) conducted by Simpson et al (1987) or in the analysis offarm data here where the pigs were on arestricted feeding regimen. Furthermore, relative to other breeds, a large 'eye muscle' area in crosssection is not a notable feature of the Duroc breed (Smith & Pearson 1986,1987.…”

“…Here the effect was a reduction of 1-3 mm with scale-fed pigs and less when the feeding regimen was ad libitum. In European studies, several workers have reported no differences in the backfat measurements of Durocand Landrace-or Large White-crosses (Sutherland et al 1984;McGloughlin et al 1986;Simpson et al 1987). Where backfat depths have been reported as being relatively lower (McGloughlin et al 1986) or higher (Madsenetal.…”

Effect of the proportion of Duroc genes in crosses with Large White and Landrace pigs on the characteristics of seasoned Parma ham

“…The effect of the Duroc breed has been extensively studied, in particular with regard to growth performance, carcass and meat quality for light (Simpson et al, 1987;Edwards et al, 1992;Liu et al, 1999;Blanchard et al, 1999) and heavy pig production (Fabbri and Bergonzini, 1979;Santoro et al, 1981;Geri et al, 1983;Bittante et al, 1989;Caleffi and Broccaioli, 1990;Bittante et al, 1990;Bonomi et al, 1991;Franci et al, 1994 a;Franci et al, 1994 b;Bittante et al, 1993;Sabbioni et al, 2002 a), fat composition (Franci et al, 1995;Sabbioni et al, 2002 b) and cured ham characteristics (Bittante et al, 1991;Bonomi et al, 1992;Gallo et al, 1994;Franci et al, 1996).…”