Gonadotropin-releasing hormone immunization and castration in male pigs: effects on growth, hormonal levels, antibody titer response, testicular function, back fat, and consumers' sensory perceptions

This study investigated the effects of gonadotropin-releasing hormone (GnRH) vaccine on pig growth, carcass quality, and sensory perceptions of pork meat by Thai consumers. Male crossbred pigs (n = 30) were separated into three groups of 10 pigs each: boars, immunocastrated pigs, and surgically castrated pigs. The immunocastrated group was immunized at 13 and 19 weeks of age with GnRH vaccine (400 µg/dose). All pigs were slaughtered at 24 weeks of age. Blood samples were collected and testes size determined. Testes weight and back fat thickness were recorded at the time of slaughter, and meat samples were collected for sensory assessment by Thai consumers. Testosterone and progesterone concentration levels decreased significantly two weeks after the second dose of GnRH (p < 0.05), and the GnRH antibody titer of the immunocastrated pigs was significantly high two weeks after the second dose of GnRH (p < 0.05). GnRH vaccine significantly reduced the weight and size of testes. Thai consumers reported no significant differences in odor or flavor among meat samples from the three groups. In conclusion, immunocastration improved growth performance, removed the need for castration surgery, and avoided “boar taint” in the meat. It has also no distinct trace of the boar taint same as pork that is currently produced from physically castrated pig which is making it acceptable to consumers.

Genetic analysis of residual feed intake adjusted for fat and carcass and performance traits in a Nellore herd / Análise genética do consumo alimentar residual ajustado para gordura e de características de carcaça e desempenho em um rebanho Nelore

ABSTRACT: The study of the genetic evaluation of residual feed intake adjusted for fat (RFIFat) is important for the appropriate use of feed efficiency in selection programs. The objective was to analyze the influence of selection for RFIF at on carcass and performance traits by estimating various genetic parameters. Data were analyzed from five tests of feed efficiency, which were conducted with 677 Nellore males. Genetic evaluation was performed by Bayesian inference using an animal model via single- and two-trait analyses. Variables analyzed were dry matter intake, average daily gain, RFIFat, rib eye area, back fat thickness, rump fat thickness, marbling score, and subcutaneous fat thickness. The posterior mean distributions estimated at each analysis were used to estimate heritability of the traits and to perform various correlations. The studied traits showed high heritability estimates, and they should respond well to selection. The RFIFat presented a phenotypic correlation with carcass traits (which was next to zero), and there was also a negative genetic correlation. Additive genetic variability for RFIFat showed that selection for this trait can promote genetic gains in future generations, resulting in animals that are efficient in terms of nutrient use, and according to the genetic and phenotypic correlations, with no significant negative changes to carcass traits.

RESUMO: O estudo da avaliação genética do consumo alimentar residual ajustado para a gordura (CARFat) é importante para o uso apropriado da eficiência alimentar em programas de seleção. Objetivou-se analisar a influência da seleção para CARFat sobre características de carcaça e de desempenho, frente à estimação dos parâmetros genéticos. Foram analisados os dados de cinco provas de eficiência alimentar, com 677 machos Nelore. A avaliação genética foi realizada por Inferência Bayesiana, com modelo animal, em análises uni e bicaracterística. Foram analisadas as variáveis: ingestão de matéria seca, ganho de peso diário, CARFat, área de olho de lombo, espessura de gordura, espessura de gordura subcutânea na picanha, marmoreio e acabamento. As médias das distribuições a posteriori, estimadas em cada uma das análises, foram usadas para a estimação das herdabilidades e das correlações. As características estudadas apresentaram altas estimativas de herdabilidades, devendo responder bem à seleção. O CARFat apresentou correlações fenotípicas próximas a zero com as características de carcaça, e correlações genéticas negativas. A variabilidade genética aditiva observada para CARFat demonstra que a seleção para essa característica poderá promover ganhos genéticos nas futuras gerações, obtendo animais eficientes na utilização de alimentos e, de acordo com as correlações genéticas e fenotípicas encontradas, sem mudanças negativas significativas às características da carcaça.

Parámetros y valores genéticos para características de composición corporal, área de ojo del lomo y grasa dorsal medidos mediante ultrasonido en la raza Brahman / Genetic parameters and values for body composition traits, rib eye area and back fat measured by ultrasound in Brahman cattle

El ganado Brahman en Colombia es el de mayor participación como raza pura paraproducción de carne, y tiene gran influencia en el ganado comercial. Hasta el momento, Asocebu ha realizado evaluaciones genéticas para características de crecimiento,pero aún no se han realizado para características de la canal. El objetivo de este trabajo fue determinar parámetros genéticos (heredabilidades y correlaciones), y valores genéticos(DEP) para área de ojo del lomo (AOL), grasa dorsal (GD), profundidad del músculo glúteo medio (PMGM) y grasa del anca (GA). Fueron medidos por medio de ultrasonido un total de 934 animales puros, hijos de 164 toros que se encontraban en un rango de edad de 15 a 18 meses. Para los análisis se crearon grupos contemporáneos teniendo en cuenta la época, el sexo y el manejo alimenticio. Se realizó un análisis univariado usando un modelo reproductor, teniendo en cuenta el grupo contemporáneo (animales del mismo sexo, de la misma época y en el mismo manejo alimenticio), la edad fue tomada como covariable y la finca fue incluida en el modelo. Las heredabilidades fueron 0,37 ± 0,11; 0,29 ± 0,10; 0,26 ± 0,10 y 0,11 ± 0,09 para AOL, GD,PMGM y GA respectivamente. Las DEP para AOL variaron de -2,84 a 3,43; para GD de -0,372 a 0,235; para PMGM de -0,187 a 0,235, y para GD de -0,176 a 0,298. Las correlaciones genéticas fueron positivas y altas indicando que la selección por musculatura no afecta el grado de acabado. Este trabajo mostró que en ganado Brahman puro existe variación genética para las características medidas por ultrasonido relacionadas con la canal, lo cual permitirá tenerlas en cuenta en el programa de mejoramiento genético de la raza Brahman en Colombia.

The Brahman cattle in Colombia is the beef cattle of greater participation as a purebreed and has greater influence over the commercial cattle. Until now Asocebu has done Genetic Evaluations for growth traits, but has not done yet for carcass traits. The objective of this work was to determinate genetic parameters (Heritabilities and correlations)and genetic values (DEP’S) to rib eye area (REA), back fat (BF), gluteus medius muscledepth of gluteus medius muscle (GMMD) and rump fat (RF). Measurements of 934progenies that were between 15 to 18 months of age of 164 Brahman sires were takenby ultrasound. To perform the analysis was create contemporary groups taking into account (animals of the same sex, same season and same feed managemen). Univariate analysis was performed using a Sire Model taking into account contemporary group(animals of the same sex, same season and same feed management), age as a covariableand the farm effect was included in the model. The estimates of heritabilities were 0.37±0.11, 0.29 ±0.10, 0.26 ±0.10 y 0.11 ±0.09 to REA, BF,GMMD and RF respectively. The EPD’S to REA oscillated of -2.84 to 3.43 cm2, for BF of -0.372 to 0.235 mm, for GMMD of -0.187 a 0.235 cm and RF of -0.176 a 0.298 mm. The genetic correlations were positives and highs indicating that the genetic selection by musculature does notaffect the fat endpoint. This work showed that in Pure Brahman cattle exist genetic variation for the carcass characteristics measures by ultrasound and this will allow include them into Genetic Improvement Program from Asocebú Colombia.

Características de carcaça de suínos de três linhagens genéticas em diferentes idades ao abate / Carcass characteristics from three swine stocks in different slaughters ages

O objetivo deste trabalho foi estudar as características da carcaça de suínos de diferentes linhagens genéticas, em diferentes idades ao abate. Foram utilizados 88 suínos por linhagem, fêmeas e machos castrados, com idade e peso médio iniciais de 74 dias e 30kg, respectivamente, pertencentes a três linhagens genéticas distintas, designadas de AgroceresPic, Dalland e Seghers. A etapa experimental foi dividida em quatro fases (Crescimento I, Crescimento II, Terminação I e Terminação II). Ao final de cada etapa, foram abatidos 60 animais (10 por linhagem/sexo), para as caracterizações: Peso (PCQ) e Rendimento de Carcaça Quente (RCQ), Área de Olho de Lombo (AOL) e Espessura de Toucinho (ET). Na análise dos resultados foi utilizado um delineamento inteiramente casualizado com desdobramento dos graus de liberdade em esquema fatorial 4 x 3 x 2, sendo quatro idades ao abate (90, 119, 150 e 186 dias), três linhagens (AgroceresPic, Dalland e Seghers) e dois sexos (fêmea e macho castrado), com 10 repetições por tratamento, sendo utilizado o pacote PROC MIXED do Softwear SAS. Os valores médios de peso vivo apresentaram diferença entre as linhagens e interação entre fase e linhagem (P<0,05). Os valores médios das demais variáveis estudadas apresentaram diferença e a interação (P<0,05) entre fase, linhagem e sexo, sendo que de maneira geral as principais diferenças ocorreram a partir da fase de Terminação I, em que as fêmeas das linhagens AgroceresPic e Dalland apresentaram melhores resultados (P<0,05) de RCQ (80,4 e 80,7 por cento, respectivamente) em comparação com os machos (78,8 e 78,7 por cento, respectivamente) e além disso as fêmeas Dalland apresentaram valores superiores (P<0,01) de AOL e ET (45,7cm² e 11,4mm x 38,3cm² e 18,3mm). Conclui-se que as linhagens genéticas avaliadas apresentaram características de carcaça muito interessantes para o mercado atual e que as fêmeas suínas podem ser utilizadas em programas que visem o abate de animais mais pesados.

The aim of this research was to study the carcasses characteristics of swine sire lines from different slaughter weights. In this study were used 88 castrated piglets (castrated males and females) per sire line (AgroceresPic, Dalland and Seghers), with initial age of 74 days and live weight of 30kg. The experiment was divided in four phases (Growing I, Growing II, Finishing I and Finishing II). Sixty animals were slaughtered (10 by stock/sex) at the end of each experimental phase to determine the post mortem measurements: Carcass Weight (CW), Hot Carcass Yield (HCW), Loin Eye Muscle Area (LMA) and Back Fat Thickness (BT). This study was conducted using a completely randomized design, with treatments in complete factorial 4 x 3 x 2, being 4 slaughters ages (90, 119, 150 and 186 days), 3 sire lines (AgroceresPic, Dalland and Seghers) and 2 sexes (female and male castrated) with 10 repetitions by treatment. The PROC MIXED from the Software SAS was applied for statistical analysis. The mean values for Live Weight present difference (P<0.05) sire line and interaction between phase and stock. The mean values for the other studied variables presented significant differences and interaction between phase, sire line and gender, remarking that in general the major differences occurred after the phase Finishing I, where the females of AgroceresPic and Dalland tended to present better results (P<0.05) of HCW (80.4 and 80.7 percent, respectively) than the castrated males (78.8 and 78.7 percent, respectively) and the females Dalland were better than the castrated males (P<0.01) on LMA and BT values (45.7cm² and 11,4mm x 38.3cm² and 18.3mm). It can be concluded that the all sire lines studied presented interesting carcass characteristics for the actual market, and that the females can be used in programs aimed at animals with more slaughter weights.

Heredabilidad estimada y comparación de genotipos puros en porcinos de las razas Duroc, Landrace y Yorkshire y en cruces recíprocos de las razas Landrace y Yorkshire, para grasa dorsal y peso a 154 días / Estimated Heritability and Comparison of Pure Genotypes in Pigs of Duroc, Landrace and Yorkshire Breeds and Reciprocal Crosses of Landrace and Yorkshire Breeds for Back Fat and Weight to 154 Days

Se utilizaron 2776 registros de cerdos, entre 1996 y 2002, de los cuales: 698 fueron Duroc, 276 Landrace, 443 Yorkshire, 1049 Landrace-Yorkshire y 309 Yorkshire-Landrace para evaluar la grasa dorsal a 105 kg de peso y peso a 154 días. Para el peso a 154 días, se observó efecto de los factores: año, raza y sexo, y las interacciones año por raza, año por sexo y año por raza por sexo. Los cerdos Landrace fueron más pesados, no se encontró diferencia entre los animales Duroc y Yorkshire; los machos fueron más pesados que las hembras. Para grasa dorsal se encontró efecto de: año, raza y sexo, y en las interacciones año por raza y año por raza por sexo. La raza con mayor cantidad de grasa fue la Duroc y la de menor, la Yorkshire. El cruce Yorkshire-Landrace fue más pesado y menos grasoso que el Landrace-Yorkshire. La heredabilidad para peso a 154 días fue de 0,26; 0,50 y 0,45 para Duroc, Landrace y Yorkshire respectivamente; para grasa dorsal, la heredabilidad fue 0,32; 0,18 y 0,53.

Were used 2776 records of growing pigs from 1996 to 2002, of which 698 was Duroc, 276 Landrace, 443 Yorkshire, 1049 Landrace-Yorkshire and 309 Yorkshire-Landrace to evaluate back fat to 105 kg and weight to 154 days. For weight effects as age, breed, sex, and the interactions age by breed, age by sex and age by breed and by sex. Landrace pigs were heavier but there wasn’t difference between Duroc and Yorkshire animals. The male were heavier than females. Also for back fat effects as age, breed, sex and the interactions age by breed and age by breed and by sex. The fattiest breed was Duroc and the breed with leaner back fat was Yorkshire. The cross Yorkshire-Landrace was heavier but fattier than Landrace-Yorkshire. The heritability for weight to 154 days was 0.26, 0.50 and 0.45 to Duroc, Landrace and Yorkshire respectively. For back fat the heritability was 0.32, 0.18 and 0.53.