Effects of immunocastration on the nutrient responses, carcass traits and meat quality of growing pigs (Sus crofa domesticus)

Thesis (MScAgric)--Stellenbosch University, 2014.ENGLISH ABSTRACT: Increased consumer awareness has motivated the industry to find alternative methods to surgical castration for controlling boar taint and aggression in male pigs. Immunocastration has been identified as a solution, however; little research has been done into the nutritional requirements of immunocastrated pigs. Thus the objective of this study was to determine the optimal protein levels for immunocastrated pigs with regards to growth performance, carcass traits and yields as well as meat quality when supplemented with or without ractopamine hydrochloride (RAC). The study involved 120 male pigs following a 2 x 2 x 3 factorial design. The main effects evaluated were sex (immunocastrated versus entire), RAC supplementation (0 versus 10 mg/kg and dietary balanced protein level (7.50 {low}, 9.79 {medium} and 12.07 {high} g lysine/kg). Vaccination occurred at 16 and 20 weeks of age and from 20 weeks each pig was allocated to one of the balanced protein diets with RAC supplementation at either 0 or 10 mg/kg for the last 28 days of growth. Slaughtering occurred at 24 weeks at which time carcass traits were measured and carcasses were processed, commercial cuts were weighed, deboned and trimmed into muscle, bone and fat portions which were then weighed individually. Immunocastration increased the average daily gain, average daily feed intake, feed conversion ratio (FCR) and backfat deposition after the second vaccination. The FCR was improved by RAC supplementation, with the best FCRs seen at the medium and high balanced protein diets. Immunocastration and RAC increased live weight at slaughter and calliper backfat thickness but no differences were seen for the dressed hot carcass weight or Hennessey Grading Probe backfat thickness. Supplementation of RAC increased the percentage of the hot carcass weight, comprising of the shoulder, hindquarter, loin and belly, as well as the shoulder muscle, hindquarter muscle and loin muscle percentages, while decreasing the fat percentage of the belly and hindquarter. Chemical composition analysis of the Longissimus thoracis (LT) muscle indicated differences (p ≤ 0.05) for crude protein content but they were considered biologically negligible. The cooking loss of the LT was decreased by immunocastration and feeding medium protein. Feeding RAC decreased the a* and b* colour values and increased the Warner Bratzler shear force (WBSF) values, resulting in less red and less tender meat. Entire males fed low dietary protein had the lowest L* values, while entire males fed medium protein diets had the highest L* values. Immunocastrates fed the low protein diet had the most tender meat, whereas immunocastrates fed the high protein diet had the least tender meat. Immunocastration decreased the androstenone levels to below 0.5 μg/g fat and although it did not significantly affect the testicle size, it influenced the morphology and increased the lightness (L*), yellowness (b*) and decreased the redness (a*) of the testicle’s cut surface colour. The results from this study indicated that the balanced dietary protein requirements for immunocastrates differ both with and without RAC supplementation and thus the correct dietary protein level needs to be provided so that growth performance and leanness is not compromised. The return per carcass can also be improved by supplementing RAC, owing to improved cutting yields and lean yields of carcasses. Together, immunocastration, RAC supplementation and the correct balanced protein diet may allow pig producers to efficiently produce heavier male carcasses without boar taint while conforming to the animal welfare expectations of the consumer. However, an incentive for producers in terms of immunocastration needs to be provided by the possible modification of the current carcass classification system so that heavier immunocastrated male carcasses are not penalised.AFRIKAANSE OPSOMMING: Die toename in verbruiker bewustheid het die bedryf gemotiveer om alternatiewe metodes vir chirurgiese kastrasie te vind, terwyl beergeur en aggressie in manlike varke beheer word. Immunokastrasie is geïdentifiseer as ʼn moontlike metode, maar min navorsing is egter tot dusver gedoen om die optimale proteïen vlakke vir hierdie immunokastrate te bepaal. Min is ook bekend oor die groei prestasie, karkas-eienskappe, opbrengs asook vleiskwaliteit van immunokastrate as raktopamien hidrocholoried (RAC) tot die dieet bygevoeg word. ʼn Studie is gevolglik gedoen met 120 manlike varke in ʼn 2 x 2 x 3 faktoriaal ontwerp. Die hoof effekte wat geëvalueer was, is geslag (immunogekastreerd of intakt), RAC byvoeding (0 of 10 mg/kg) en gebalanseerde proteïenvlak (7.50 {lae}, 9.79 {medium} en 12.07 {hoë} g lisien/ kg). Inenting het plaasgevind op 16 en 20 weke ouderdom en van 20 weke was elke vark toegeken aan een van die gebalanseerde proteïen diëte met RAC byvoeding teen 0 of 10 dpm vir die laaste 28 dae van groei. Diere is geslag op 24 weke ouderdom, waartydens karkaseienskappe gemeet was. Die karkasse is vervolgens opgesny en die kommersiële snitte geweeg. Die snitte is verder verwerk en spier, been en vet is afsonderlik geweeg. Immunokastrasie het die gemiddelde daaglikse toename, gemiddelde daaglikse voerinname, voeromsetverhouding (VOV) en rugvet dikte verhoog na die tweede inenting. Die VOV is verbeter deur RAC byvoeding, met die beste VOVs waargeneem op die medium en hoë gebalanseerde proteïen diëte. Resultate het getoon dat beide immunokastrasie en RAC gelei het tot ʼn toename in lewendemassa by slag asook vernier rugvetdikte, alhoewel daar geen verskil tussen warm karkasmassa of Hennessey Grading Probe (HGP) rugvetdikte was nie. Aanvulling van RAC verhoog die skouer, agterkwart, lende en pens uitgedruk as persentasie van die warm karkasmassa. Die massa, uitgedruk as persentasie van warmkarkasmassa, van die skouerspier, agterkwartspier en lendespier is ook verhoog terwyl pensvet verlaag het. Chemiese analise van die Longissimus thoracis (LT) spier het aangedui dat die ru-proteïen inhoud verskil (p ≤ 0.05) alhoewel die verskille wat gevind was waarskynlik nie biologiese waarde het nie. Die persentasie kookverlies van die LT is verlaag deur immunokastrasie en die middel proteïenvlak-dieet. Die byvoeding van RAC het die a* en b* kleurwaardes verlaag en die Warner-Bratzler-shear-force (WBSF)-waardes verhoog, wat gelei het tot minder rooi vleis asook minder sagtheid. Intakte varke wat ʼn lae proteïen dieet gevoer was, het die laagste L* waardes getoon terwyl intakte varke wat ʼn middel proteïenvlak-dieet gevoer was die hoogste L* waardes getoon het. Immunokastrate wat ʼn lae proteïen-dieet gevoer was, het die sagste vleis gelewer, maar immunokastrate wat ʼn hoë proteïen-dieet gevoer was, het die taaiste vleis gelewer. Immunokastrasie het die konsentrasie androstenoon tot onder 0.5 μg/g vet verlaag en alhoewel dit geen betekenisvolle effek op testikel grootte gehad nie, het dit die morfologie van die testikel geaffekteer asook die ligheid (L*) en geelheid (b*) verhoog en die rooiheid (a*) van die gesnyde testikel oppervlakte verlaag. Die resultate van hierdie studie dui daarop dat die gebalanseerde proteïen vereistes vir immunokastrate verskil vir immunokastrate met en sonder RAC byvoeding. Dit is dus belangrik dat die korrekte proteïenvlak en aminosuur samestelling gevoer moet word vir die spesifieke dier onder beskouing ten einde groeiprestasie en maerheid te maksimeer. Die opbrengs per karkas kan ook verbeter word deur die byvoeding van RAC, as gevolg van die verbeterde snit-opbrengs en maer-vleis opbrengs van karkasse. Die kombinasie van immunokastrasie, RAC aanvullings asook die korrekte gebalanseerde proteïen-dieet skep die moontlikheid aan varkprodusente om swaarder beerkarkasse doeltreffend te produseer sonder die teenwoordigheid van beergeur terwyl daar terselfdertyd aan die verbruiker se dierewelsyn-wense voldoen word. Die insentief vir die produsent is egter nog afwesig en daarom is dit nodig dat die klassifikasie stelsel hersien moet word ten einde te verseker dat daar nie teen immunogekastreerde diere op die slaglyn gediskrimineer word nie

Immunocastration and its application in ram lambs

Thesis (PhD)--Stellenbosch University, 2018.ENGLISH ABSTRACT: In South Africa, Dohne Merino sheep are farmed extensively for wool and meat production. Ram lambs are typically castrated to enable easier management of mixed-sex flocks by manipulating reproduction and associated behaviour, while promoting fattening and improving meat quality. Due to various welfare concerns regarding the pain associated with castration and healing complications, the practice is under scrutiny, which necessitates producers to investigate alternatives to physical castration. International pork and beef industries have successfully applied immunocastration in commercial enterprises; however, no formal recommendations regarding its commercial application in the lamb industry are available. Improvac® was administered at two doses during the interval from weaning until slaughter and was sufficient in supressing testes growth and functioning in Dohne Merino ram lambs. Varying the interval between the two doses (two, three or four weeks) and the interval between second vaccination and slaughter (four or six weeks) did not influence growth performance or slaughter performance of ram lambs after weaning. The primary vaccine dose decreased serum testosterone concentrations, which resulted in a decrease in scrotal circumference, semen quality and seminiferous tubule size for all immunocastration vaccination schedules. Testes cut surface colour was redder and more yellow in immunocastrated than in intact rams, providing a possible on-line detection method for vaccination success after slaughter to ensure correct sex classification. An inter-vaccination period of two weeks and a six-week interval after second vaccination until slaughter, had the most pronounced and sustained effect on reproductive capacity of the rams, as well as the lowest frequency of injection site reactions. The recommended injection protocol for the commercial application of Improvac® in lambs involves subcutaneous administration on the flat surface of the shoulder area, and alternating shoulder sides per dose. Immunocastration resulted in improved welfare of ram lambs, when compared to rams castrated using the Burdizzo-method. The latter method resulted in increased serum cortisol concentrations, abnormal behaviours in response to pain experienced during the procedure, despite the use of pain mitigation, and tissue necrosis. Minor differences in offal yields were observed in immunocastrated lambs but no influence on carcass cutting yield or meat quality, other than cut surface colour, was reported. Thus, immunocastration can be considered a feasible alternative to physical castration in the commercial production of Dohne Merino ram lambs. However, further investigation is recommended into the application of immunocastration within a feedlot environment to further elucidate the effects on feed intake, nutrient requirements, differential fat deposition and behaviour in Dohne Merinos and other important meat-producing breeds in South Africa.AFRIKAANSE OPSOMMING: In Suid-Afrika word daar ekstensief met Dohne Merino skape geboer vir wol- en vleisproduksie. Ramlammers word tipies gekastreer om die bestuur van gemengde-geslags troppe te vergemaklik deur voortplanting en gepaardgaande gedrag te manipuleer, terwyl die bevordering van vetheid en vleiskwaliteit ook verbeter word. Weens verskeie welsynsbekommernisse, rakende die pyn wat verband hou met kastrasie en genesingskomplikasies, word die praktyk onder die loep geneem, wat produsente noodsaak om alternatiewe vir fisiese kastrasie te ondersoek. Internasionale vark- en bees industrieë het immunokastrasie al suksesvol in kommersiële ondernemings toegepas; daar is egter geen formele aanbevelings beskikbaar aangaande die kommersiële toepassing daarvan in die lamsbedryf nie. Twee doserings van Improvac® was toegedien tydens die interval van speen tot slag en was voldoende om testesgroei en -funksionering van Dohne Merino ramlammers te onderdruk. Wisseling van die interval tussen die twee dosisse (twee, drie of vier weke) en die interval tussen die tweede inenting en slagting (vier of ses weke), het nie die groeiprestasie of slagprestasie van ramlammers beïnvloed nadat dit gespeen is nie. Die primêre entstof dosis het serum testosteroonvlakke verminder, wat gelei het tot 'n afname in skrotale omtrek, semengehalte en seminifereuse buisie grootte vir alle immunokastrasie-inentingskedules. Die testis se gesnyde oppervlakkleur was rooier en meer geel vir die immunokastreerde ramme in vergelyking met die ongeskonde ramme, wat 'n moontlike vroeë deteksie metode bied om suksesvolle inenting na slagting te bepaal indien die inenting sukses bevraagteken word. 'n Inter-inentingsperiode van twee weke en 'n ses-week interval na die tweede inenting tot slag, het die grootste en mees volgehoue uitwerking op die voortplantingskapasiteit van die ramme, asook die laagste frekwensie van inspuitingsreaksies, gehad. Die aanbevole inspuiting protocol vir die kommersiële toediening van Improvac® vir lammers behels onderhuidse toediening op die plat oppervlak van die skouer area met die afwisseling van skouerkante per dosis. Immunokastrasie het gelei tot ‘n verbeterde welsyn van ramlammers in vergelyking met ramme wat met die Burdizzo-metode gekastreer is. Laasgenoemde metode het gelei tot verhoogde serum kortisolvlakke en abnormale gedrag in reaksie op pyn wat tydens die prosedure ervaar is, ten spyte van die gebruik van pynbeperking en weefselnekrose. Geringe verskille in afval opbrengste is waargeneem vir immunokastreerde lammers, maar geen invloed op karkas opsny opbrengs of vleiskwaliteit, behalwe gesnyde oppervlakkleur, is gerapporteer nie. Daarom kan immunokastrasie beskou word as 'n haalbare alternatief vir fisiese kastrasie tydens die kommersiële produksie van Dohne Merino ramlammers. Verdere ondersoek word egter aanbeveel vir die toepassing van immunokastrasie binne 'n voerkraalomgewing om die effekte op voerinname, voedingstof vereistes, differensiële vetdeposisie en die gedrag van Dohne Merinos en ander belangrike vleisproduserende skaaprasse in Suid-Afrika verder te verhelder

Influence of extending the pre-slaughter interval after second vaccination on the carcass cutting yield and the quality of meat from immunocastrated lambs

The influence of extending the vaccination-to-slaughter interval of immunocastrated lambs on carcass cutting yield and meat quality of the Longissimus thoracis (LT) muscle was investigated in forty Dohne Merino lambs (8.5 months old; 53.7 ± 4.8 kg). Immunocastration booster vaccination intervals of six (IC6; n = 10) and four (IC4; n = 10) weeks prior to the slaughter age were used, with two weeks between primary and secondary vaccinations. A further 10 lambs were Burdizzo-castrated at 6.5 months old (B). The control treatment remained intact (R; n = 10). Prime cutting yields, LT muscle area, LT subcutaneous fat thickness and instrumental meat quality were accessed. Both castration methods increased LT fat thickness and decreased meat CIE a* (redness) values. Extending the vaccination-to-slaughter interval of immunocastrates increased the gastrointestinal tract fat and decreased meat redness. Immunocastration of male lambs can thus be used to manipulate backfat without negatively influencing carcass weight, cutting yield or meat quality

Sensory Characteristics of Male Impala (Aepyceros melampus) Meat, Produced under Varying Production Systems and Nutrition

The objective of this study was to determine the influence of three production systems (intensive, semi-extensive and extensive) with differing nutrition on the descriptive sensory and fatty acid profiles of sub-adult (±15–18 months old) male impala longissimus thoracis et lumborum (LTL) muscles. The discriminant analysis plot showed that extensively produced impala had a sensory profile distinct from the intensive and semi-extensive system impala. Extensively produced impala had the highest sensory ratings for overall intensity, gamey, beef-like, herbaceous, and sweet-associated aroma and flavor of their meat. The intensive and semi-extensive system impala did not differ for most of the sensory attributes, except for higher ratings for gamey flavor, liver-like flavor, tenderness and mealiness, and lower ratings for residue found in semi-extensive system impala. The overall aroma and flavor intensities of impala meat in general had strong positive correlations with gamey, beef-like, herbaceous, and sweet-associated aromas and flavors; however, marketing should be adjusted depending on the nutrition received by the impala, to allow consumers to select their preferential sensory profile. Impala meat from all three production systems had low fat contents (<2%), and desirable fatty acid profiles

Physical changes during post-mortem ageing of high-value impala (Aepyceros Melampus) steaks

Antelope meat production is rapidly growing, not only due to their adaptation to marginal land usage, but also because of its favorable nutritional properties and free-range production. However, limited information is available on the meat quality and processing potential of game meat for commercial consumption. The objective of this study was to determine the ageing period to achieve maximum tenderness of longissimus thoracis et lumborum (LTL) muscles of impala. The LTL muscles of 11 male and 11 female impala were harvested, and divided into eight portions. Each portion was randomly allocated to 1, 2, 4, 6, 8, 10, 12, or 14 days of wet-ageing (4 °C) in vacuum packaging. The meat pH, color, weep loss, cooking loss, and Warner–Bratzler shear force were measured throughout ageing. Initially the ageing profile differed depending on the sex of the animal from which the muscle was harvested; however, after 8 days of ageing, maximum tenderness was reached (13.5 ± 0.91 N) and no further sex differences were seen. Ageing improved the surface color of all meat until day 8, after which discoloration occurred. Therefore, it is recommended that impala LTL steaks should be wet-aged at 4 °C for eight days to achieve maximum tenderness and minimize sex variability

Ante-and post-mortem strategies to improve the meat quality of high-value muscles harvested from farmed male common eland (Taurotragus oryx)

The effects of immunocastration, pelvic suspension and wet ageing on the meat quality of the longissimus lumborum et thoracis (LTL) and biceps femoris (BF) muscles of male common eland were evaluated. Ten subadult males were either immunocastrated (n = 5) or remained intact (n = 5) throughout a four-month growth trial, after which their carcass sides were randomly allocated to either pelvic- or Achilles-suspension. The LTL and BF were further aged for 14 days, measuring changes in the physical quality weekly. The sensory quality of the LTL and BF were determined after ageing (8/9 days, respectively). Immunocastration had minimal effects on the meat quality of male eland, but pelvic suspension decreased the shear force. All muscles reached minimum shear force after seven days of ageing, and the panellists ranked the pelvic-suspended muscles higher for tenderness traits. Incorporating pelvic suspension and wet ageing into the commercial processing of eland carcasses should be considered to improve overall meat quality

Influence of ageing on the physical qualities of the longissimus thoracis et lumborum and biceps femoris muscles from male and female free-ranging common eland (Taurotragus oryx)

The physical quality changes (pH, purge loss, cooking loss, drip loss, Warner-Bratzler shear force and CIE Lab colour) of vacuum-packaged longissimus thoracis et lumborum (LTL) and biceps femoris (BF) muscles were determined for male (n = 6) and female (n = 6) eland during a 35-day post-mortem ageing period at 4 °C. The BF and LTL muscles reached maximum tenderness (57 to 67 N) at Day 17 and 21, respectively, but could still be considered tough after ageing. Purge losses increased throughout ageing for the two muscles, respectively; however, cooking loss decreased. Meat surface colour turned brighter, more red and yellow with ageing. Initially the BF muscle was more tender, had less purge loss and higher CIE a* and b* values than the LTL, however as the ageing period progressed the differences between the muscles became less apparent. Thus, ageing improved uniformity between muscles as well as tenderness, with minor influences of sex thereon

Sex influence on muscle yield and physiochemical characteristics of common eland (Taurotragus oryx) meat

To investigate the potential of eland for meat production, the yield, physical quality and chemical composition of seven muscles were characterized from both male (n = 6) and female (n = 6) carcasses. Although carcass weights did not differ, cows had greater biceps femoris (BF), semitendinosus (ST) and supraspinatus (SS) muscle yields. The semimembranosus (SM) from cows had the greatest drip loss and were more yellow (b*) than all muscles evaluated from both sexes. Shear force measurements showed no effect of sex but large variations between muscles existed (65.5 to 97.6 N). Moisture content was greater within the BF, SS, ST and infraspinatus (IS) than the longissimus thoracis et lumborum (LTL) and SM. The LTL and IS had the lowest intramuscular fat content, while the LTL and SM muscle had the highest crude protein content. Sex had little effect on eland meat composition, showing potential for the meat of both sexes to be marketed as a lean meat source

Combined effect of dietary protein, ractopamine, and immunocastration on boar taint compounds, and using testicle parameters as an indicator of success

CITATION: Needham, T. et al. 2020. Combined effect of dietary protein, ractopamine, and immunocastration on boar taint compounds, and using testicle parameters as an indicator of success. Foods, 9(11):1665, doi:10.3390/foods9111665.The original publication is available at https://www.mdpi.comThis study investigates the combined effect of immunocastration, dietary protein level (low, medium or high) and ractopamine hydrochloride supplementation (0 or 10 mg/kg) on the adipose concentrations of androstenone, skatole and indole in pigs, and explores whether body mass, carcass fatness or testicular parameters may be indicators of boar taint in these carcasses. Immunocastration was successful in decreasing testicle functioning, and adipose androstenone and skatole concentrations, in all individuals. Immunocastration decreased testicle weight and length, seminiferous tubule circumference and epithelium thickness. Testicle tissue from immunocastrates was also paler, and less red in color, in comparison to non-castrated controls. Dietary protein level and ractopamine hydrochloride supplementation had no influence on the adipose concentration of androstenone, skatole and indole. Testicle size and color were moderate to strong indicators of androstenone and skatole concentrations in the carcasses, and thus vaccination success. Immunocastration together with the adjustment of dietary protein and ractopamine hydrochloride supplementation, is successful in preventing boar taint while maintaining growth performance.South African Pork Producers’ OrganisationSouth African Research Chairs in Meat Science Initiativehttps://www.mdpi.com/2304-8158/9/11/1665Publisher's versio

Habituation of common eland (Taurotragus oryx) to intensive routine handling, and the effect of immunocastration thereon

The temperament of captive common eland (Taurotragus oryx) during handling is crucial for their management, as they have been identified as an ideal antelope for game meat farming, and are well-represented in captive antelope populations world-wide. Generally speaking, common eland are considered undomesticated, and thus maintain their natural prey instincts, making it necessary to habituate them to routine handling. Immunocastration can be implemented as part of the herd management strategy in mixed or single-sex eland groups, and might reduce aggressive behaviour of males by blocking the production of testosterone, thereby improving docility for ease of handling. Within this study, data was collected to determine the influence of routine handling and immunocastration on the temperament of common eland during handling. Twenty-nine common eland were divided into two groups: sub-adults (n = 15; ca. 2 years old; 182.9 ± 59.37 kg) and juveniles (n = 14; ca. 6 months old; 94.18 ± 24.76 kg), and they were routinely handled every two weeks over a four-month period (10 handling events). Within each age group, females, males, and immunocastrated males were present. Immunocastration treatment was administered during the second and fourth handling events (2 mL Improvac®/ animal). During handling, animals were individually driven through the raceway and finally restrained in a squeeze chute, where routine biological samples and measurements were collected. Faecal androgen metabolite (fAM) concentrations were measured for each event, for males only. Each animal was focally sampled for specific behaviours during the handling. A temperament score was obtained by observing the general state of the animal from the point of entering the raceway, until its exit from the squeeze chute. Generalized linear mixed models tested the influence of immunocastration, week, group, fAM concentration, and body weight on the temperament score. Immunocastration did not affect the temperament score, the general state in the squeeze chute, the order of entering the handling system, and the chute exit. However, the temperament score and the state in the squeeze chute improved overtime (with animals being less nervous). Moreover, animals with low temperament scores (calmer) entered the system earlier, and exited the system calmly over the repeated handling period. The results show that routine handling through a raceway and squeeze chute system leads to habituation, and improves the ease of handling in common eland. However, immunocastration did not affect the temperament of the male common eland during handling.The Internal Grant Agency of the Faculty of Tropical AgriSciences – Czech University of Life Sciences, Prague and the Ministry of Education, Youth and Sport of the Czech Republic (MŠMT ČR):International Mobility of Research Staff at CZU Prague.https://www.elsevier.com/locate/applanimhj2022Mammal Research InstituteZoology and Entomolog