Effects of immunological castration (Improvest) on further processed belly characteristics and commercial bacon slicing yields of finishing pigs

Abstract

Objectives were to compare fresh belly characteristics, further processed belly characteristics, and commercial bacon slicing yields of immunologically castrated (IC) barrows, IC barrows fed ractopamine hydrochloride (IC+RAC), physically castrated (PC) barrows, intact males, and gilts. One hundred eighty-eight bellies from pigs housed in single sex pens (n = 48) slaughtered at 130 kg ending live weight were evaluated for flop distance, length, width, thickness, and fatty acid composition. Bellies were injected, thermally processed, and sliced according to standard protocols at a USDA federally inspected facility. Complete slices were sorted by trained plant personnel. Then, sliced bellies were individually packaged to maintain anatomical orientation. The effects of treatments were analyzed as a generalized linear mixed model with pen of pigs serving as the experimental unit for all comparisons. Belly thickness was not different (P ≥ 0.11) in bellies from IC barrows (3.74 cm) compared with bellies from IC+RAC (3.60 cm), PC barrows (3.94 cm), or gilts (3.64 cm); however, bellies were 0.42 cm thicker (P < 0.01) in IC barrows compared with intact males. Iodine value was not different (P ≥ 0.06) in bellies from IC barrows (68.26) compared with bellies from IC+RAC (69.78), PC barrows (67.55), or gilts (69.45); however, iodine value was 2.32 units less (P < 0.01) in IC barrows compared with intact males. Green weight was not different (P ≥ 0.09) in bellies from IC barrows (4.88 kg) compared with bellies from IC+RAC (5.11 kg), PC barrows (5.10 kg), or gilts (4.79 kg); however, green weight was 0.56 kg greater (P < 0.0001) in IC barrows compared with intact males. Pump uptake and cooked yield was not different (P ≥ 0.15) among treatment groups. Slicing yield (as a percentage of green weight) was decreased (P ≤ 0.01) in bellies from IC barrows (93.61%) compared with bellies from PC barrows (98.42%) or gilts (98.19%); however, slicing yield was not different (P ≥ 0.11) among bellies from IC barrows, IC+RAC, or intact males. Overall, fresh belly characteristics of IC barrows were analogous to PC barrows and gilts, but commercial slicing yields of bacon manufactured from IC barrows were less than both PC barrows and gilts.

Review: Pork belly quality, bacon properties and recent consumer trends

“…Scramlin et al (2008) observed significant increases in belly yield with positive effect on bacon quality (in terms of lean content) from pigs fed up to 5 ppm RAC even with no significant changes in belly thickness, pump uptake and belly flop. Kyle et al (2014) also supported this trend when they found that RAC addition helped to ameliorate some negative effects of IC on commercial slicing yield in pork belly regardless of the observed increase in fat unsaturation. Similarly, Leick et al (2010) observed no significant effect of RAC on pork belly quality, including thickness, width, trimmed weight, length, firmness and fat colour.…”

“…Most of these authors observed lower cooked yield, trimmed cooked weight, sliced weight (Tava´rez et al 2014) and overall slice yield percentage (Kyle et al 2014;Tava´rez et al 2014) in IC compared with PC barrows observed under the same conditions and exposure period, whereas gilt and PC barrow do not differ in slice yield percentage although gilt bellies appears softer and of higher fatty acid unsaturation than those of PC barrows (Kyle et al 2014). In terms of composition, moisture content seems to be higher, lipid content lower and lean:fat ratio higher in IC compared with PC barrows, confirming that increased lean content may be related to reduced slicing yield (Kyle et al 2014). Furthermore, considering the possibility of lower structural lipids (e.g., phospholipids) and higher lipogenic activity in belly fats compared with other fat depots, the effect of fat deposition or modification on belly quality due to dietary intake may be more pronounced in barrows than in gilts (Warnant et al 1999;Benz et al 2010;Xu et al 2010).…”

“…More recently in the literature, a digital imaging system has been employed to assess the bacon slice composition in terms of total lean and fat area. The digital images are usually analyzed with specific software where the total lean and fat areas are measured (Scramlin et al 2008;Kyle et al 2014;Tava´rez et al 2014). Aside from these, there is no available standardized bacon quality measurement technique referred to in the scientific literature.…”

“…The effect of physical (PC) and immunological (IC) castration of barrows on various pork belly and bacon characteristics has recently been reported (Boler et al 2012;Asmus et al 2014;Kyle et al 2014;Tava´rez et al 2014). Bellies from IC barrows have generally been reported to be leaner, thinner and with softer fat with higher UFA (Boler et al 2012;Tava´rez et al 2014), which may result in lower bacon-slicing yield (Kyle et al 2014).…”

“…Bellies from IC barrows have generally been reported to be leaner, thinner and with softer fat with higher UFA (Boler et al 2012;Tava´rez et al 2014), which may result in lower bacon-slicing yield (Kyle et al 2014). Most of these authors observed lower cooked yield, trimmed cooked weight, sliced weight (Tava´rez et al 2014) and overall slice yield percentage (Kyle et al 2014;Tava´rez et al 2014) in IC compared with PC barrows observed under the same conditions and exposure period, whereas gilt and PC barrow do not differ in slice yield percentage although gilt bellies appears softer and of higher fatty acid unsaturation than those of PC barrows (Kyle et al 2014). In terms of composition, moisture content seems to be higher, lipid content lower and lean:fat ratio higher in IC compared with PC barrows, confirming that increased lean content may be related to reduced slicing yield (Kyle et al 2014).…”