Influence of sex and castration on growth performance and carcass quality of crossbred pigs from 2 Large White sire lines1

Abstract

In total, 360 pigs slaughtered at 125 kg of BW and destined for the dry-cured industry were used to study the influence of sex and castration [immunocastrated males (IMC), surgically castrated males (CM), and intact females (IF)] in 2 terminal Large White sire lines [Top York (TY) and Tempo (TE)] on growth performance and carcass and meat quality. The female line was Large White × Landrace. The IMC pigs were immunized against gonadotropin-releasing factor (GnRF) with Improvac at 78 (experimental d 16) and 126 (experimental d 64, 48 d before slaughter) d of age. Each of the 6 treatments was replicated 6 times (10 pigs/pen). Through the day of the first Improvac injection (62 to 78 d of age), IMC and IF grew at a slower rate (P < 0.001) than CM with no differences (P = 0.95) in feed intake. The CM had greater G:F than IF, with IMC being intermediate (P < 0.01). From 78 to 126 d of age (between Improvac injections), the IMC pigs ate less feed (P < 0.001) and grew at a slower rate than CM, with IF being intermediate. The IMC pigs were more feed efficient than IF, and both were more efficient than CM (P < 0.001). However, from 126 to 174 d of age (from the second Improvac injection to slaughter), IMC pigs grew at a faster rate (P < 0.001) and were more efficient (P < 0.001) than IF and CM. Overall, IMC and CM pigs grew at a faster rate (P < 0.01) than IF, and IMC were more efficient than the other sexes (P < 0.001), but had reduced (P < 0.001) carcass yield compared with CM and IF. The IMC and IF pigs also had less (P < 0.001) backfat depth than CM. Intact females had greater (P < 0.01) loin yield but less intramuscular fat than IMC and CM and greater (P < 0.05) fresh and trimmed ham yields than CM, with IMC being intermediate. Crossbreds from TE sires grew at a faster rate (P < 0.001) than crossbreds from TY sires, but no differences (P = 0.23 and 0.14, respectively) were found for feed intake or efficiency. Crossbreds from TY produced greater (P < 0.05) fresh and trimmed ham yield, but less (P < 0.01) loin yield and intramuscular fat content than crossbreds from TE. In conclusion, IMC pigs are more efficient, but have less carcass yield than CM and IF. The intramuscular fat content is least for IF and similar for IMC and CM. Crossbreds from TE sires were larger and had greater intramuscular fat content, but slightly less trimmed ham yield compared with crossbreds from TY sires. Immunocastrated pigs can replace CM for the production of heavy pigs destined for the dry-cured industry. Because of increased carcass weight, crossbreds from TE sires may have an advantage over crossbreds from TY sires.

Effect of immunocastration in group-housed commercial fattening pigs on reproductive organs, malodorous compounds, carcass and meat quality

“…This is in agreement with our previous study (Škrlep et al, 2010), whereas Gispert et al (2010) and Morales et al (2010) reported intermediate position of IC compared to SC and EM for IMF in semimembranosus and gluteus medius muscle, respectively. Studies comparing only IC and SC reported either no difference (Morales et al, 2011) or lower LD intramuscular fat in IC (Boler et al, 2011). If the deposition of IMF is related to other fat depots, such as leaf fat, LEA fat, and neck intermuscular fat, a similar pattern is observed, i.e.…”

“…There are not many studies dealing with the immunocastration effect on meat quality. They show for the most part the absence of any effect on pH 24 (Pauly et al, 2009;Gispert et al, 2010;Škrlep et al, 2010;Boler et al, 2011;Morales et al, 2011;), drip loss or colour (Pauly et al, 2009;Škrlep et al, 2010;Boler et al, 2011). On the other hand, some reports indicate IC to have darker meat than SC (Silveira et al, 2008), lighter than EM or lower drip loss than SC (Miclat-Sonaco et al, 2008).…”

Field experience with surgical castration with anaesthesia, analgesia, immunocastration and production of entire male pigs: performance, carcass traits and boar taint prevalence

“…These observations are in line with the studies conducted by Lundstrom et al, (2009) and Bonneau (1998) who indicated that the advantage of lean meat growth when shifting towards EM pigs may have decreased because of selection for leaner pig breeds. None of the studies on the interaction between genotype and castration method on carcass quality published thus far showed any significant interactions (D'Souza and Mullan, 2003;Morales et al, 2011 and. When shifting towards the production of immunocastrates or EM, it is relevant for the farmers to consider whether it is appropriate to continue with the current genetic line or whether it would be economically beneficial to change to lines characterised by a lower lean meat percentage and higher DG.…”

The effect of single-gender and mixed rearing on growth performance, backfat thickness and meat quality in crossbred growing-finishing pigs

“…Regarding the gender effect, barrows grew faster and had lower feed conversion ratio than gilts had been demonstrated by previous study (Morales et al, 2011). Meanwhile, Ellis et al (1996) reported that carcass yield was greater for gilts than castrates.…”