Growth performance, carcass characteristics, fresh belly quality, and commercial bacon slicing yields of growing-finishing pigs from sire lines intended for different industry applications

Ambivalence towards pork belly: exploring its significance and contradictions from the perspectives of the food industry and nutritional science

Pork is the most consumed meat in South Korea, and pork belly is the preferred cut. However, pork production cannot meet the demand, leading to a heavy reliance on imports, particularly for pork bellies. In contrast, low-fat cuts face oversupply problems owing to low demand and export challenges. Pork belly fat content varies with breed, sex, growth rate, and fatty acid composition. Western countries favor higher fat saturation for processed products, whereas South Koreans prefer grilled or roasted bellies. Excessive consumption of high-fat pork cuts like pork belly, which is rich in saturated fatty acids, can increase the risk of severe diseases, highlighting the importance of reducing saturated fat intake and increasing the consumption of monounsaturated fatty acids and polyunsaturated fatty acids to mitigate these risks. The pork industry and public health sector should diversify production, promote leaner pork, and raise awareness about the implications of excessive pork consumption.

Evaluation of Improvest effects on production parameters of gilts from two different genetic sire lines

The objective was to evaluate the effects of Improvest on the performance and carcass characteristics of gilts from two different genetic sire lines and the performance of Improvest gilts with castrated male pigs. It was hypothesized that performance parameters observed for Improvest gilts would be similar to barrows, thus narrowing the performance gaps between traditionally managed gilts and barrows. Pigs were from Large White/Landrace dams and either Duroc-Pietrain (DP) or Duroc (D) sires. Females within each genetic sire line were randomized by weight to receive the first dose of Improvest (IMP) on day 25 of the study or to serve as a nontreated control (DP IMP gilt (n = 6 pens; 19 pigs/pen), D IMP gilt (n = 6 pens; 19 pigs/pen), DP CON gilt (n = 6 pens; 19 pigs/pen), D CON gilt (n = 6 pens; 19 pigs/pen). The second dose of Improvest was administered 6 wk later (i.e., day 67). Barrows did not receive Improvest (DP barrow [n = 10 pens; 19 to 20 pigs/pen], D barrow [n = 10 pens; 19 to 20 pigs/pen]). Average daily gain (ADG), average daily feed intake (ADFI), and gain-to-feed ratio (G:F) were measured at 21 d intervals throughout the duration of the study. The targeted weight for pigs to be marketed was 133 ± 2.5 kg. Carcass characteristics and loin quality parameters were evaluated on a subset of pigs (n = 283). Improvest-treated gilts of both genetic lines had increased (P ≤ 0.05) ADG and ADFI compared to untreated gilts during the post-second dose intervals with values exceeding that of barrows from day 84 to marketing. Overall, DP IMP gilts had increased (P ≤ 0.05) G:F post-second dose compared to DP CON gilts and DP barrows, yet all other treatments were similar. As pigs were marketed at a similar weight, there was no difference in the final weight, however, DP IMP gilts and DP barrows reached market weight sooner (P ≤ 0.05) than DP CON gilts (109.9 and 111.8 vs. 114.3 ± 0.8 d). Backfat and loin weight were greater (P < 0.01) in IMP gilts versus CON gilts, while IMP gilts and barrows had similar values within each respective genetic sire line. There were no differences between treatments (P ≥ 0.08) for pH and instrumental color of the loins. When the pass rate of loins (Japanese color score ≥ 3.0 and marbling ≥ 2.0) was evaluated, IMP gilts were at intermediate values between CON gilts and barrows for each respective genetic sire line. Overall, Improvest within a genetic line improved gilt carcass measurements so that they were more similar to barrows.

The effect of immunocastration of male and female Duroc pigs on the morphological, mechanical and compositional characteristics of pork belly

Pork belly is an important and heterogeneous cut, characterized by its fat content. Immunocastration is an alternative to surgical castration that can modify the composition of carcasses and cuts and it can affect at its processing. This work compares the morphological, mechanical and compositional characteristics of pork belly of (1) pure Duroc pigs from surgically castrated males (CM), entire females (EF) and immunocastrated females (IF), and (2) Duroc crossbreed pigs from immunocastrated males (IM) and entire males (EM). Two trials were carried out: Trial 1, in which 36 bellies were evaluated, 12 from each sexual type, CM, EF and IF; and Trial 2, where 30 bellies were used, 15 from each sexual type, IM and EM. Results show few differences in bellies from EF and IF, while those from CM were fatter and firmer and with lower polyunsaturated fat. Bellies from IM were longer and firmer than those from EM, and their skin was thinner. IM bellies had higher saturated and lower polyunsaturated fat than those from EM. To conclude, the sex of the pigs affects belly characteristics and this could be a criterion for determining the destination of the bellies in the cutting plant. Immunocastration of pure Duroc females had a lower effect on the belly characteristics when compared to those from entire females, but some differences could be found in the fat distribution. Immunocastration of Duroc crossbred males produces firmer and thicker bellies, with a thinner skin, that could be advantageous for slicing and further processing.

A comparison of carcass characteristics, carcass cutting yields, and meat quality of barrows and gilts

Objectives of this research were to compare carcass characteristics, carcass cutting yields, and meat quality for market barrows and market gilts. Commercially-sourced carcasses from 168 market barrows and 175 market gilts weighing an average of 107.44 ± 7.37 kg were selected from 17 different slaughter groups representing approximately 3,950 carcasses. Each group was sorted into percentiles based on hot carcass weight with an equal number of barrows and gilts selected from each quartile so that weight minimally confounded parameters of interest. Carcass lean yield was determined for carcasses following fabrication (i.e. dissection of lean, fat, and bone tissue components) and meat quality measurements were evaluated at the time of fabrication (24 to 72 h postmortem) and following 14-d of postmortem storage. Data were analyzed as a randomized complete block design with carcass serving as the experimental unit, sex (barrow or gilt), the three hot carcass weight quantiles (light [<104 kg]; average [104 to 110 kg]; heavy [>110 kg]), and the interaction between sex and hot carcass weight quantile serving as fixed effects, and producer nested within slaughter event serving as a random effect. Results from the study demonstrated that gilt carcasses were leaner (3 mm less backfat thickness; 3.5 cm2 greater loin muscle area, 1.52% greater merchandized-cut yield, and 2.92% greater dissected carcass lean yield; P < 0.01) than barrow carcasses, while loins from barrows were higher quality (0.43% more intramuscular fat and slightly less shear force; P < 0.01) than loins from gilts. While this study confirms the well-known biological principle that barrow carcasses have greater levels of fat deposition and lower levels of carcass leanness when compared with gilt carcasses, this study provides a much-needed quantification of these differences for the commercial industry that will undoubtedly be useful as new technologies emerge in upcoming years.

Comparison of an advanced automated ultrasonic scanner (AutoFom III) and a handheld optical probe (Destron PG-100) to determine lean yield in pork carcasses

This study compared the accuracy of two methods for predicting carcass leanness (i.e., predicted lean yield) with fat-free lean yields obtained by manual carcass side cut-out and dissection of lean, fat, and bone components. The two prediction methods evaluated in this study estimated lean yield by measuring fat thickness and muscle depth at one location with an optical grading probe (Destron PG-100) or by scanning the entire carcass with advanced ultrasound technology (AutoFom III). Pork carcasses (166 barrows and 171 gilts; head-on hot carcass weights (HCWs) ranging from 89.4 to 138.0 kg) were selected based on their fit within desired HCW ranges, their fit within specific backfat thickness ranges, and sex (barrow or gilt). Data (n = 337 carcasses) were analyzed using a 3 × 2 factorial arrangement in a randomized complete block design including the fixed effects of the method for predicting lean yield, sex, and their interaction, and random effects of producer (i.e., farm) and slaughter date. Linear regression analysis was then used to examine the accuracy of the Destron PG-100 and AutoFom III data for measuring backfat thickness, muscle depth, and predicted lean yield when compared with fat-free lean yields obtained with manual carcass side cut-outs and dissections. Partial least squares regression analysis was used to predict the measured traits from image parameters generated by the AutoFom III software. There were method differences (P < 0.01) for determining muscle depth and lean yield with no method differences (P = 0.27) for measuring backfat thickness. Both optical probe and ultrasound technologies strongly predicted backfat thickness (R2 ≥ 0.81) and lean yield (R2 ≥ 0.66), but poorly predicted muscle depth (R2 ≤ 0.33). The AutoFom III improved accuracy [R2 = 0.77, root mean square error (RMSE) = 1.82] for the determination of predicted lean yield vs. the Destron PG-100 (R2 = 0.66, RMSE = 2.22). The AutoFom III was also used to predict bone-in/boneless primal weights, which is not possible with the Destron PG-100. The cross-validated prediction accuracy for the prediction of primal weights ranged from 0.71 to 0.84 for bone-in cuts and 0.59 to 0.82 for boneless cut lean yield. The AutoFom III was moderately (r ≤ 0.67) accurate for the determination of predicted lean yield in the picnic, belly, and ham primal cuts and highly (r ≥ 0.68) accurate for the determination of predicted lean yield in the whole shoulder, butt, and loin primal cuts.

The Implications of Changing Age and Weight at Slaughter of Heavy Pigs on Carcass and Green Ham Quality Traits

Simple Summary

Conventional rearing systems for heavy pigs intended for Italian dry-cured ham production require pigs to be slaughtered at 160 ± 16 kg and a minimum age of 9 months. With the current animal genetic trends providing progressively leaner animals, the conventional rearing system fails to provide pigs with optimal characteristics for the dry-cured ham industry. In this research, new combinations of age and weight at slaughter were explored, using different feeding conditions, as possible alternative rearing strategies for heavy pigs. Such alternative rearing strategies aimed to manipulate the growth rate of pigs, first allowing them to reach 160 ± 16 kg slaughter weight at a younger age; second, allowing pigs to maximize their slaughter weight at 9 months of age; and third, inducing slow growth in the pigs to reach the 160 ± 16 kg body weight at an older age. The first two strategies were the most promising alternatives as they improved the rate of gain, feed efficiency, and ham adiposity of the pigs. While the first strategy was the most economically convenient, the second produced the hams with the highest quality.

Abstract

Italian dry-cured ham production requires pigs to be slaughtered at 160 ± 16 kg at 9 months of age (control, C). The study explored three alternatives, based on different feeding conditions: (1) allowing pigs to express their growth potential by letting them reach 160 ± 16 kg slaughter weight (SW) at younger slaughter age (SA) (younger Age, YA); (2) allowing pigs to express their growth potential by maximizing their SW at 9 months SA (greater weight, GW); (3) increasing the SA required to reach 160 ± 16 kg SW (older age, OA). Pigs (336 C21 Goland, 95 kg initial body weight) were slaughtered on average at 257, 230, 257, and 273 d SA and 172.7, 172.3, 192.9, and 169.3 SW kg for the four treatments, respectively. C pigs had an average daily gain (ADG) of 715 g/d and feed efficiency (FE) of 0.265 (gain to feed). Compared to C, YA pigs had higher ADG (+32%), FE (+7.5%), and better ham adiposity; GW pigs had higher carcass weight (+12%), ADG (+25%), trimmed ham weight (+10.9%), and better ham adiposity. OA treatment affected ADG (−16.4%), FE (−16.6%), and trimmed ham weight (−3.6%). YA and GW could be promising alternatives to C as they improved FE and ham quality traits.

Investigation of Physicochemical and Sensory Quality Differences in Pork Belly and Shoulder Butt Cuts with Different Quality Grades

The objective of this study was to investigate the effects of quality grade (QG) on the physicochemical composition and eating quality attributes of pork belly and shoulder butt. Seventy-two growing-finishing crossbred pigs were slaughtered and their carcasses were graded according to the Korean pork carcass grading system. Based on the grading criteria, the carcasses were classified into: QG 1⁺ (n=23), QG 1 (n=23) and QG 2 (n=26) groups. At 24 h postmortem, belly and shoulder butt cuts were collected from the QG groups and used for analysis of meat quality, flavor compounds and eating quality attributes. Results showed that the variation in fat content among QG was approximately 2% in the both cut types. The QG showed no effects on all the quality traits: cooking loss, pH and color of the belly or shoulder butt (p>0.05). Thirty-five flavor compounds comprising mainly fatty acids oxidation/degradation-derived products (e.g., aldehydes) and only few Maillard reaction-derived products (e.g., sulfur-and nitrogen-containing compounds) were identified. However, the QG showed a minor effect on the flavor profiles in both the belly and shoulder butt. Regarding the sensory quality, no effects of the QG were found on all the eating quality attributes (color, flavor, juiciness, tenderness and acceptability) for both the belly and shoulder butt cuts (p>0.05). Thus, it may be concluded that the current pork carcass grading standards do not reflect the real quality and value of the belly and shoulder butt cuts.

Effects of sire line, birth weight and sex on growth performance and carcass traits of crossbred pigs under standardized environmental conditions

A variety of available terminal sire lines makes the choice of terminal sire line complex for the pig producer. Higher birth weights are important for subsequent growth performance and selection for this trait is also necessary in sire lines. The aim was to investigate the effect of sire line, birth weight and gender on growth performance, carcass traits and meat quality. In total 3844 crossbred pigs from Camborough Pig Improvement Company (PIC) dams matched with either a Synthetic (A) or Piétrain (B) sire line were used. Pigs from line A grew faster (p<0.01), showed higher feed intake (p<0.01) and reached a higher final body weight (p≤0.01), but they had a similar efficiency (p=0.179). Leaner carcasses and heavier primal cuts (p<0.001) were observed in pigs from line B. Carcasses from pigs sired by line A had higher meat quality (p<0.001). Males had a higher growth rate (p≤0.05) but had a poorer feed efficiency (p<0.01). Heavier birth weight pigs and females had leaner, higher value carcasses with heavier primal cuts (p<0.001) compared to middle and low birth weight females or males. Sire line by sex interactions was significant for growth (p≤0.05) and carcass traits (p<0.001). Interaction between sire line and birth weight classes were only detected for loin depth (p<0.01). Line A is preferable if the numbers of fatting pigs per fattening place and year should be improved, and line B is an option to increase leanness and carcass primal cuts.

Effect of porcine reproductive and respiratory syndrome virus infection and soy isoflavone supplementation on carcass cutability and meat quality of pigs

The objective was to evaluate the effects of porcine reproductive and respiratory syndrome virus (PRRSV) infection and dietary soy isoflavone (ISF) supplementation on carcass cutability and meat quality of commercial pigs. Barrows (21 d of age) were randomly allotted to experimental treatments that were maintained throughout the study: noninfected pigs received an ISF-devoid control diet (CON, n = 22) and infected pigs received either the control diet (PRRSV-CON, n = 20) or that supplemented with total ISF in excess of 1,500 mg/kg (PRRSV-ISF, n = 25). Pigs were penned by treatment, with six pigs within a pen. Following a 7-d adaptation, weanling pigs were inoculated once intranasally with either a sham-control (phosphate buffered saline [PBS]) or live PRRSV (1 × 105 tissue culture infective dose [TCID]50/mL, strain NADC20). Pigs were maintained on experimental diets for 166 d after inoculation and then slaughtered (192 or 194 d of age; approximately 120 kg body weight [BW]). At 1-d postmortem, left sides were separated between the 10th and 11th rib for the determination of loin eye area (LEA), backfat (BF) thickness, and loin quality (ultimate pH, instrumental color, drip loss, visual color, marbling, and firmness). Loin chops were aged 14 d postmortem prior to Warner-Bratzler shear force (WBSF) determination. Belly width, length, thickness, and flop distance were determined. Data were analyzed as a one-way ANOVA with pig as the experimental unit. Carcass yield, LEA, BF, and estimated lean percentage did not differ (P > 0.26) among treatments. Loins from CON pigs had increased ultimate pH (P = 0.01), reduced L* scores (P = 0.005) coupled with darker visual color scores (P = 0.004), were firmer (P < 0.0001), and exhibited reduced drip loss (P = 0.01) compared with PRRSV-CON and PRRSV-ISF pigs. However, WBSF did not differ (P = 0.51) among treatments after 14 d of aging. Bellies from CON pigs were more firm compared with bellies from PRRSV-CON and ISF pigs (P < 0.01). These data suggest PRRSV infection did not alter carcass characteristics but may have marginally reduced loin and belly quality. Supplementation with dietary soy isoflavones did nothing to mitigate the detrimental effects of PRRSV infection.