A total of 80 pigs, representing Large White and Landrace boars and gilts were slaughtered at an average live weight of 92.3 kg (80.5 – 102.5 kg). Boars were housed in groups of five pigs per pen, and were individually fed to appetite twice daily for a period of 45 min. Gilts were housed in groups of 12 pigs per pen. The diet consisted of 21% crude protein with 3300 kcal kg−1 digestible energy. Carcasses were weighed on the slaughter floor and cooled at 1 °C for 24 h prior to dissection of the left side into fat, bone and lean. There were no significant breed-by-gender interactions for growth, carcass and meat quality traits. These pigs had low average backfat, when measured ultrasonically according to Canadian Swine Improvement Program standards on the live pig (gilts 12.3 mm, boars 10.1 mm), high average daily gain (ADG: gilts 880, boars 940 g d−1) and low age adjusted to 90 kg (gilts 148, boars 145 d). Large White boars had a lower feed conversion ratio (2.18 vs. 2.32, P = 0.015) and less feed intake per day (2.05 vs. 2.14 kg d−1P = 0.020) than did Landrace boars. There were no significant differences in dissected lean yield between breeds (P = 0.389) or genders (P = 0.148). However, gilts had greater carcass grade fat and greater lean depth measurements than did boars, such that both genders had a predicted lean yield of 51.8%. Gilts (40.8 cm2) had a larger (P < 0.001) longissimus dorsi area than boars (38.0 cm2). There were no breed effects on the lean content of the four major cuts (P = 0.20), but boars had less fat (P = 0.01) and more bone than gilts (P < 0.01). There were few consistent differences in subjective or objective meat quality traits (i.e. color, drip loss) among breeds or genders. Boars had muscle with greater moisture than gilts (P < 0.001) as well as softer fat (P = 0.016). Thus, it appears possible to produce pork of high quality from lean animals and that lean boars efficiently produce carcasses of equivalent yield and quality to carcasses produced by lean gilts. Key words: Swine, boar, carcass composition, meat quality, Landrace, Large White
Inferences on the effects of selection for feed conversion over meat quality traits in broiler
