Alterações fisiológicas e comportamentais de bovinos de corte após o manejo de castração / Physiological and behavioral changes of beef cattle after castration management

Objetivou-se avaliar o desempenho, parâmetros fisiológicos e temperamentais de bovinos de corte não castrados ou submetidos à castração cirúrgica ou à imunocastração. O período experimental foi dividido em dois subperíodos de observações: primeiros 15 dias pós-castração (período de cicatrização) e os 25 dias seguintes à cicatrização. Nos primeiros 15 dias de avaliação, os animais não castrados obtiveram maior ganho médio diário de peso em relação aos castrados cirurgicamente. A frequência cardíaca foi maior para os animais castrados cirurgicamente, com 126,51 batimentos/minuto, em relação aos demais tratamentos. A distância de fuga foi superior para os novilhos castrados cirurgicamente, com valor de 12,22 metros. Nos 25 dias seguintes à castração cirúrgica, o ganho médio diário de peso foi superior nos bovinos castrados cirurgicamente em relação aos bovinos não castrados ou imunocastrados. A velocidade de fuga, no segundo subperíodo de avaliação, foi superior nos bovinos castrados em relação aos não castrados. O período imediato à castração, os primeiros 15 dias, prejudicou o ganho médio diário e o ganho de peso total, o que causou maior reatividade, com alterações nos parâmetros fisiológicos e temperamentais de bovinos castrados cirurgicamente em comparação com bovinos não castrados, entretanto, transcorrido o período de cicatrização, essas diferenças diminuíram ou desapareceram.(AU)

The aim of this study was to evaluate the performance, physiological and temperamental parameters of uncastrated beef cattle or those submitted to surgical castration or immunocastration, in the post-castration period. The experimental period was divided into two subperiods of observations: the first 15 days post-castration (healing period) and the 25 days following healing. In the first 15 days of evaluation, the non-castrated animals obtained a greater average daily gain of weight in relation to surgically castrated. The heart rate was higher for surgically castrated animals with 126,51 beats/minute, compared to the other treatments. The distance of escape was higher for the surgically castrated steers, with a value of 12,22 meters, when compared to the other groups studied. During the next 25 days of surgical castration, the mean daily gain of weight was higher in surgically castrated cattle than in non-castrated or immunocastrated cattle. The escape velocity, in the second evaluation subperiod, was superior in the castrated cattle, in relation to the not castrated. The immediate castration period, the first 15 days, altered the mean daily gain and the total weight gain, the physiological and temperamental parameters of surgically castrated cattle, however, after the healing period, these differences diminish or disappear.(AU)

Performance and plasma urea nitrogen of immunocastrated males pigs of medium genetic potential / Rendimiento y nitrógeno de urea en plasma de cerdos machos inmunocastrados de potencial genético medio

Objective. A study was carried out to evaluate the performance and the plasma urea nitrogen (PUN) of male pigs of medium genetic potential for lean meat deposition in carcass, which underwent immunocastration. Materials and methods. Forty-five seventy-days old Large White x Landrace crossbred were used. The pigs were distributed in a randomized design in three treatments: castrated males, females and immunocastrated males. Each treatment group was replicated three times with five pigs per replicate. The trial period was of 70 days, divided into phases of growing (70 to 110 days old) and finishing (111 to 140 days old). The pigs were weighed four times: at the beginning of the trial, at the first immunocastration vaccine dose (80 days old), at the second immunocastration vaccine dose (110 days old) and just before slaughter (140 days old). Blood samples were taken on the same day that the animals were weighed. Results. Between 80 and 110 days old, there was an increase in PUN value, only for castrated males and females. No differences were found in weight gain between the studied groups within the periods. Immunocastrated males had lower feed intake than females and these had a lower feed intake than castrated males. To 110 days old, immunocastrated animals showed feed conversion ratio similar to females and better than castrated males. However, after the second dose of the vaccine, feed conversion was similar between groups. Conclusions. The benefits of immunocastration are prominent in animals with low to medium genetic potential.

Objetivo. Se realizó un estudio para evaluar el rendimiento y la concentración de urea en plasma (PUN) de los cerdos machos de medio potencial genético de carne magra en la canal sometidos a la inmunocastración. Materiales y métodos. Se utilizaron 45 cerdos de 70 días de edad Landrace x Large White. Los animales se distribuyeron en un diseño completamente al azar con tres tratamientos: machos castrados, hembras y machos inmunocastrados. Cada tratamiento consistió en tres repeticiones, con cinco animales por réplica. El período experimental fue de 70 días, divididos en las etapas de crecimiento (70 a 110 días de edad) y terminación (111 a 140 días de edad). Los cerdos fueron pesados cuatro veces: al inicio del experimento, en la primera dosis de vacuna de inmunocastración (80 días de edad), en la segunda dosis de la vacuna de inmunocastración (110 días de edad) y antes de el sacrificio (140 días de edad). Las muestras de sangre se recogieron en el mismo día en que se pesaron los animales. Resultados. Entre 80 y 110 días de edad, hubo un aumento en la cantidad de PUN, sólo para machos castrados y hembras. No hubo diferencias en la ganancia de peso entre los grupos en ninguno de los períodos estudiados. Machos inmunocastrados tuvieron menor consumo de alimento que las hembras y éstas mostraron un menor consumo que los machos castrados. En 110 días de edad, los animales inmunocastrados mostraron la conversión de alimento similar a las hembras y mejor que los machos castrados. Sin embargo, después de la segunda dosis de la vacuna, la conversión alimenticia fue similar entre los grupos. Conclusiones. Los beneficios de inmunocastración son prominentes en animales con bajo a médio potencial genético.

Avaliação técnico-econômica de suínos machos imuno e cirurgicamente castrados / Technical-economic evaluation of imuno and surgically castrated male pigs

Realizou-se este estudo com o objetivo de avaliar o desempenho técnico-econômico e determinar a lucratividade, por meio da análise de sensibilidade econômica, de suínos machos imuno (IM) e cirurgicamente castrados (MC). Foram realizados dois experimentos, em delineamento inteiramente casualizado, composto por dois tratamentos (IM e MC), com oito repetições de 10 animais cada, totalizando 160 suínos por experimento. Verificou-se que suínos IM apresentam menor consumo de ração e melhor conversão alimentar nas fases de crescimento em relação aos MC. Na fase de terminação, suínos IM apresentam melhor ganho de peso, conversão alimentar, rendimento de carcaça e porcentagem de carne em relação aos MC. A utilização de IM aumenta a lucratividade na produção de suínos. A análise de lucratividade entre suínos IM e MC deve considerar todas as fases de criação, uma vez que o desempenho diferencial dos suínos não castrados na fase de crescimento influencia economicamente os resultados da produção.

This study was conducted to evaluate the technical and economic performance and determine profitability through the economic sensitivity analysis of immune (IM) and male pigs surgically castrated (SC). Two experiments were conducted in a completely randomized design, consisting of two treatments (IM and SC) with eight replicates of 10 animals each, totaling 160 pigs per experiment. It was found that IM pigs have lower feed intake and feed conversion during the growth phases in relation to SC. In the finishing phases, IM have better weight gain, feed conversion, carcass yield and lean meat percentage in relation to SC. The use of IM increases the profitability in pig production. The analysis of profitability differential between IM and SC should consider all stages of creation, since the differential performance of not castrated pigs during growth influences economic results of production.

Incidência da carne PSE (pale, soft, exsudative) em suínos em razão do tempo de descanso pré-abate e sexo / Resting time pre-slaughter and sex on the incidence of PSE (pale, soft, exsudative) meat in pigs

Avaliou-se o efeito do período de descanso pré-abate e do sexo sobre a incidência de carne PSE (pale, soft, exudative) em suínos. Foram realizadas três visitas a abatedouro comercial, nas quais se mensurou o pH das carcaças (n=2128) aos 45 minutos após o abate, de lotes compostos por fêmeas, machos castrados cirurgicamente e machos imunocastrados e de lotes mistos (fêmeas e machos castrados cirurgicamente), submetidos a período de descanso que variou de duas a 16 horas. Carcaças com pH45≤5,8 foram classificadas como PSE, e com pH45>5,8 como normais. Em função do número de animais avaliados dentro de cada categoria, estimou-se a frequência de carne PSE. A incidência total de carne PSE foi de 10,1%, sendo maior nos lotes de animais imunocastrados (13,5%) quando comparados aos lotes de fêmeas (8,6%) ou de machos castrados cirurgicamente (8,5%). Períodos de descanso menores que seis horas e acima de 14 horas aumentaram a incidência de carne PSE. Período de descanso entre seis e oito horas minimizaram a ocorrência de carnes PSE.

Were evaluated the effect of lairage pre-slaughter and sex on the incidence of PSE (pale, soft and exudative) meat in pigs. There were three visits to a commercial slaughterhouse, in which the pH of carcasses (n=2128) was measured at 45 minutes after slaughter of lots consisting exclusively of females, males castrated surgically, males immunologically castrated and mixed lots (females and castrated surgically) underwent a resting time, and time between the shipment and slaughter ranged from two to 16 hours. Carcasses with pH45≤5.8 were classified as PSE and with pH45>5.8 as normal. Depending on the number of animals evaluated in each category we estimated the frequency of PSE. The overall incidence of PSE meat was 10.1%, higher in lots of animals immunocastrated (13.5%) compared to lots of females (8.6%) or castrated males (8.5%). Resting time of less than six hours and up to 14 hours increased the incidence of PSE meat. Resting time between six and eight hours minimized the occurrence of PSE meat.

Ractopamina em dietas para suínos machos imunocastrados, castrados e fêmeas / Ractopamine in diets for immunocastrated, barrows and females

O objetivo do trabalho foi avaliar o desempenho e as características quantitativas de carcaça de suínos machos imunocastrados, castrados e fêmeas, na fase de terminação, alimentados com dietas contendo 10ppm de ractopamina. Foram utilizados 120 animais, com peso inicial de 99,1±5,3kg, distribuídos em delineamento de blocos ao acaso, em esquema fatorial 2 x 3 (dois níveis de ractopamina, 0 e 10ppm e três sexos), cinco repetições com quatro animais cada. A inclusão de 10ppm de ractopamina na dieta melhorou (P<0,05) a conversão alimentar dos suínos, independentemente do sexo. A inclusão de ractopamina prejudicou (P<0,05) o ganho de peso dos machos imunocastrados e aumentou (P<0,05) o ganho de peso dos machos castrados e das fêmeas, sem, no entanto, afetar (P>0,05) as características quantitativas de carcaça dos suínos. O sexo foi determinante para o desempenho e as características quantitativas de carcaça; as fêmeas apresentaram rendimento de carcaça quente superior (P<0,05) aos machos imunocastrados, que apresentaram rendimento superior (P<0,05) aos machos castrados. Os machos imunocastrados e as fêmeas apresentaram maior (P<0,05) percentual de carne magra em relação aos machos castrados. Os resultados desta pesquisa evidenciam a necessidade de estudos visando à adequação dos níveis nutricionais das dietas contendo ractopamina para suínos imunocastrados.

The objective of this study was to evaluate the performance and the quantitative characteristics of carcass of immunocastrated, barrows and females in the finishing phase fed with diets containing 10ppm of ractopamine. One hundred and twenty animals were used, with initial weight of 99.1±5.3kg, distributed in a randomized blocks factorial design in 2 x 3 (two ractopamine levels, 0 and 10ppm and three sex), five replicates of four animals each. The inclusion of 10ppm of ractopamine in the diet improved (P<0.05) feed conversion in pigs, independent of sex. The inclusion of ractopamine damaged (P<0.05) the weight gain of the immunocastrated and increased (P<0.05) the weight gain of the barrows and the females, without, however, affect (P>0.05) quantitative carcass characteristics of pigs. The sex was determining factor in performance and carcass quantitative traits and the females had higher (P<0.05) hot carcass yield for immunocastrated male and they have yield above (P<0.05) the barrows. Immunocastrated males and females had higher (P<0.05) percentage of lean meat for barrows. The results of this study highlight the need for studies to adjust the nutrient levels of diets containing ractopamine to immunocastrated pigs.

Induction of castration by immunization of male dogs with recombinant gonadotropin-releasing hormone (GnRH)-canine distemper virus (CDV) T helper cell epitope p35

Immunocastration is a considerable alternative to a surgical castration method especially in male animal species for alleviating unwanted male behaviors and characteristics. Induction of high titer of antibody specific for gonadotropin-releasing hormone (GnRH) correlates with the regression of testes. Fusion proteins composed of canine GnRH and T helper (Th) cell epitope p35 originated from canine distemper virus (CDV) F protein and goat rotavirus VP6 protein were produced in E. coli. When these fusion proteins were injected to male dogs which were previously immunized with CDV vaccine, the fusion protein of GnRH-CDV Th cell epitope p35 induced much higher antibody than that of GnRH-rotavirus VP6 protein or GnRH alone. The degeneration of spermatogenesis was also verified in the male dogs immunized with the fusion protein of GnRH-CDV Th cell epitope p35. These results indicate that canine GnRH conjugated to CDV Th cell epitope p35 acted as a strong immunogen and the antibody to GnRH specifically neutralized GnRH in the testes. This study also implies a potential application of GnRH-based vaccines for immunocastration of male pets.