The effects of immunological castration and corn dried distillers grains with solubles withdrawal on growth performance, carcass characteristics, fatty acid analysis, and iodine value of pork fat depots1,2

Abstract

A total of 1,360 pigs were used in a 125-d study to determine the effects of corn dried distillers grains with solubles (DDGS) withdrawal after immunological castration (Improvest, Zoetis, Kalamazoo, MI) on growth performance and carcass fat quality of pigs. Pens of male pigs (initially 24 kg) were randomly allotted by BW and castration method (physically castrated [PC] or immunologically castrated [IC] barrows) to 1 of 3 diets with 8 replications per treatment and 27 to 29 pigs per pen. Treatments were arranged in a 2 × 3 factorial with main effects of castration method and diet (0% DDGS throughout, 30% DDGS throughout, or 30% DDGS through d 75 then no DDGS to d 125). Intact males were injected with Improvest on d 39 and 74 (IC). No castration method × diet interactions (P > 0.12) were observed for growth performance. Before the second Improvest injection (d 0 to 74), PC barrows had increased (P < 0.05) ADFI but were less efficient (P < 0.05) than intact males. After the second Improvest injection until the first marketing event (d 74 to 107), IC barrows had improved (P < 0.05) ADG and G:F compared with PC barrows. From d 0 to 107, IC barrows had improved (P < 0.05) ADG, G:F, and lower ADFI than PC barrows. The inclusion of 30% DDGS decreased (P < 0.05) G:F compared with pigs fed the control diet. For the period after the second Improvest injection (d 74 to 125), IC barrows had increased (P < 0.05) ADG, ADFI, and G:F compared with PC barrows. Overall (d 0 to 125), IC barrows had improved (P < 0.05) ADG and G:F and lower ADFI than PC barrows. The inclusion of 30% DDGS decreased (P < 0.05) G:F. Carcass yield was lower (P < 0.05) for IC than PC barrows. Pigs fed 30% DDGS throughout had decreased (P < 0.05) carcass yield; however, withdrawing DDGS from the diet on d 74 was effective at fully recovering the yield loss. Carcass fat iodine values (IV) were consistently higher (P < 0.05), regardless of fat depot or harvest time when 30% DDGS were included in the diet. Multiple 2-way interactions (P < 0.05) were detected between castration method, DDGS, depot, and time. Interactions were a result of fatty acid profiles changing more rapidly in backfat and belly fat than in jowl fat from d 107 to 125 and more dramatically in IC than PC barrows in the same period. This improvement from d 107 to 125 could be caused by the dilution of unsaturated fatty acids, specifically C18:2 and C18:3, due to rapid deposition of fat from de novo synthesis in IC barrows.

The effects of male and female immunocastration on growth performances and carcass and meat quality of pigs intended for dry-cured ham production: A preliminary study

“…In fact, Wood et al (2008) reported that at least 4 mm of difference are required to detect changes in the fatty acid profile. Moreover, in the current work, the time elapsed from the second vaccination to slaughter (54 d) could not be enough to modify fat composition according to the work of Asmus et al (2014).…”

Ractopamine supplementation improves leanness and carcass yield, minimally affecting pork quality in immunocastrated pigs

“…Liver increase in IC pigs was also reported by a number of authors (Pauly et al, 2009;Asmus et al, 2014;Boler et al, 2014;Tavárez et al, 2014;Moore et al, 2016). As PC barrows have no testes, their steroid hormones are absent, allowing the liver to function more efficiently with regard to the metabolism of compounds such as skatole, thus affecting liver activity, which could influence liver weight.…”

“…However, when pigs were immunized, they showed a tendency to have less marbling, probably because IC pigs spend most of their lives as intact males which deposit less fat (Asmus et al, 2014). IMF content was likely to decrease, especially when 5 mg kg -1 of RAC were added to the diet, probably due to rapid down regulation of the β-receptors in the fat tissue (Dunshea et al, 2005).…”

“…Given this scenario, RAC becomes more economically viable as it amplifies immunocastration benefits by allowing pigs to perform as intact males until the second vaccination (Asmus et al, 2014), altering feed intake and tissue deposition thereafter (Dunshea et al, 2013). Moreover, both practices are additive in terms of improving growth performance and carcass characteristics (Lowe et al, 2014).…”

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

“…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).…”