Productive performance, carcass and meat quality of intact and castrated gilts slaughtered at 106 or 122 kg BW

Influence of Sex on Meat and Fat Quality from Heavy Alentejano Pigs Finished Outdoors on Commercial and High Fiber Diets

This work aimed to examine the effects of sex on meat and fat quality traits from thirty Portuguese Alentejano (AL) pigs reared in outdoor conditions. These pigs were divided into three groups and fed ad libitum. From ~40 to 130 kg LW, castrated (C group) and intact animals (I and IExp) consumed commercial diets. Until slaughter (~160 kg), C and I pigs remained on commercial diets, and IExp changed to a more sustainable experimental diet with locally produced pulses and byproducts. Samples were collected from the Longissimus lumborum (LL), Psoas major (PM), and dorsal subcutaneous fat (DSF). At ~160 kg, the PM muscle of intact pigs presented lower intramuscular fat content than that of C pigs, while total collagen was higher. Additionally, PM myoglobin was lower and lightness (L*) was higher in intact pigs. Regarding DSF, moisture and total protein contents were higher and total lipids were lower in intact than in castrated pigs, while color parameters were not significantly different. Finally, antioxidant capacity measured in the LL muscle showed an overall lower value in intact pigs. However, lipid oxidation values were not significantly different between the experimental groups and only increased with storage time. Outdoor-reared intact AL pigs produced leaner and less saturated pork and fat compared to castrated ones. Despite the lower antioxidant activity observed in the LL muscles of intact pigs, the lipid oxidative stability of cooked meat was not different among the experimental groups.

Effect of Immunocastration on Culled Sows-A Preliminary Study on Reproductive Tract, Carcass Traits, and Meat Quality

The Bísaro pig is a Portuguese autochthonous breed greatly appreciated for its meat quality and is mainly reared outdoors. Immunocastration could be a solution to avoid undesirable pregnancies and boar taint in cull sows. The present study tested three immunocastration protocols (with Improvac®) according to their reproductive cycle. The first inoculation was performed two weeks after farrowing (IM1, n = 5), at the beginning of estrus (IM2, n = 5), and one week after the end of estrus (IM3, n = 5), followed by a second administration four weeks apart. A control group (C, n = 5) was also included in the same housing conditions. The sample collection included the reproductive tract for morphometric evaluation, neck fat for the quantification of boar taint compounds, and a portion of the Longissimus thoracis et lumborum for meat quality trait assessment. The reproductive tracts from intact sows (C) were significantly heavier compared to the immunocastrated groups (p < 0.05) (1.403 kg C to 0.508 kg IM1, 0.590 kg IM2, and 0.599 kg IM3), suggesting the regression of the reproductive tract to nonstimulated conditions due to immunization against GnRH. The IM1 group exhibited significantly smaller reproductive tract measurements compared to group C for most of the evaluated segments (p < 0.05). No marked differences were observed in the meat quality traits. Therefore, immunocastration can be used in culling sows to avoid ovarian activity, and it is not detrimental to pork quality traits.

Effect of immunocastration on growth performance, gonadal development and carcass and meat quality of SuHuai female pigs

The present study was aimed to compare growth performance, gonadal development, carcass characteristic and meat quality among SuHuai entire, immunocastrated and surgically castrated female pigs. Eighty 12-week-old SuHuai gilts were randomly assigned to the following four treatment groups with four pigs per pen and five replicate pens per treatment: control (PBS injection), two-dose Improvac regimen (V2), three-dose Improvac regimen (V3) and surgical castration (S). All pigs had ad libitum access to standard diets and water. The performance and occurrence of oestrus were recorded in the trial. Backfat thickness and loin eye muscle area were recorded ultrasonically. The pigs were slaughtered to measure the weight and size of the uterus, and the weight and activity of the ovaries, to determine the serum concentrations of progesterone, and to evaluate the quality of carcass and meat. There were no significant differences in growth performance among the four groups, except for the V2, which had a better average daily feed intake (P &lt; 0.05). Carcass and meat quality were comparable among the four groups; however, the intramuscular fat in control was higher than the V2 and V3 (P &lt; 0.01). Mean ovary and uterus weights and oestrus of female pigs in V2 and V3 were significantly (P &lt; 0.01) lower than in control, but the difference between the V2 and V3 was not significant. The concentration of progesterone in the control was significantly higher than that in the V2, V3 and S (P &lt; 0.05). These results indicated that immunocastration successfully suppressed gonadal development and had no adverse effects on growth performance, or carcass or meat-quality traits in Chinese SuHuai female pigs.

A comparison of female and castrate pigs slaughtered at weights above and below 120 kg on carcass traits, intramuscular fat and fatty acid composition of carcasses intended for dry-cured ham and shoulder production

The objective of this trial was to study the impact of slaughter weight (SW) class: heavy (≥120 kg) or light (&lt;120 kg) on carcass fatness, development of main lean cuts and fat composition in barrows and gilts intended for dry-cured ham and shoulder elaboration. A total of 181 Duroc × (Landrace × Large White) pigs was used, being 94 barrows and 87 gilts. Carcasses from barrows had lower ham compactness but higher shoulder:ham weight ratio than those from gilts. The allometric growth coefficient of ham was higher in gilts whereas those for shoulder, loin and shoulder/ham were higher in barrows. An interaction sex × SW class was found for carcass fatness; the increase of fat thickness was higher in barrows than in gilts in light SW class but higher in gilts than in barrows in heavy SW class. In addition, the allometric growth coefficients for ham, loin and shoulder:ham ratio were higher in light than in heavy pigs. Percentage of rejected carcasses at slaughterhouse, due to lack of fat thickness, was higher for females than for barrows and for light than for heavy pigs. Sex and SW class had no effect on intramuscular fat content. However, more saturation was found in fat (intramuscular) from barrows and in that (subcutaneous) from light pigs. It can be concluded that carcasses from barrows are commercially more suitable than those from gilts and heavy SW might be more interesting when animals are intended for Teruel dry-cured ham and shoulder production.

Diet composition and slaughter age up to 24weeks have minimal impact on pork eating quality of loin steaks and silverside roasts from female pigs

Female crossbred pigs were randomly allocated at 16weeks of age to one of three dietary treatments (A: corn and soybean meal; B: wheat and canola meal; C: wheat and sorghum) matched for digestible energy (13.6MJ DE/kg) and total lysine (0.93-0.95%) and fed for 4, 5 or 8weeks, respectively, prior to slaughter. Loin (M. longissimus thoracis et lumborum) and silverside (M. biceps femoris) were obtained from 20 pigs per dietary treatment group and prepared into steaks and roasts, respectively, for consumer evaluation with ageing treatments of 7 and 28days post-slaughter allocated within muscle. Neither dietary treatment/age at slaughter nor ageing treatment influenced sensory traits of either cut. Intramuscular fat levels were also not influenced by dietary treatment. Higher (P<0.001) fail rates for silverside roasts compared with loin steaks indicate that different interventions are needed at a cut level to optimise pork eating quality consistency and consumer expectations.

Regrouping of pigs by body weight at weaning does not affect growth performance, carcass quality or uniformity at slaughter of heavy weight pigs

We studied the influence of pen uniformity at weaning (7.5 ± 0.6 kg vs. 7.5 ± 1.2 kg body weight (BW ± SD)) and sex on growth performance during the nursery (7.5 to 27.3 kg BW) and the fattening (27.1 to 130.5 kg BW) phases and carcass quality of barrows and castrated females (CF). During the nursery phase, pigs from the more uniform pens had lower feed efficiency (P = 0.05) than pigs from the less uniform pens. Also, barrows had higher average daily feed intake (ADFI) (P < 0.05) and average daily gain (P < 0.001) and better feed efficiency (P < 0.001) than CF. During the fattening phase, initial pen uniformity did not affect growth performance of the pigs but barrows tended (P = 0.08) to have higher ADFI and worse feed efficiency than CF. Trimmed primal cut yield tended to be higher for the more uniform pigs and better for barrows than for CF (P = 0.09). It is concluded that regrouping of the pigs at weaning according to uniformity of BW did not affect growth performance or carcass quality of the pigs at slaughter. Castrated females might be used as an alternative to barrows for the production of carcasses destined to the dry-cured industry.