Chromium and energy restriction as substitutes for ractopamine in finishing gilts diet / Cromo e restrição energética em substituição a ractopamina na dieta de leitoas em terminação tardia

This study evaluated chromium supplements and energy restriction as substitutes for ractopamine in the diets of late finishing gilts. Sixty gilts were used, with initial weights of 98.87 ± 0.25 kg and final weights of 122.69 ± 10.97 kg, distributed in a randomized block design with five diets: control; yeast chromium (0.8 ppm); chromium picolinate (0.48 ppm); ractopamine (20 ppm) and energy restriction (reduction of 150 kcal of EM kg-1 of feed), with six replicates and two animals per experimental unit. Feeding diet containing ractopamine enabled better (P<0.05) feed conversion and greater weights of the hot carcass of the gilts. The diet containing ractopamine exhibited a lower (P<0.05) cost of feed per kilogram of gain and higher economic efficiency, when compared to diets containing chromium and energy restriction; these exhibited better outcomes, compared to the control diet. Diets supplemented with chromium and ractopamine resulted in a higher (P<0.05) percentage and quantity of lean meat and a higher rate of carcass bonus, when compared to the control diet and energy restriction. The energy reduction did not harm the gilts' responses, compared to the control diet. Ractopamine supplementation allowed for a better feed conversion, lower feed cost per kilogram of gain, and a higher economic efficiency index. Supplements of chromium and ractopamine increased the percentage and quantity of lean meat and the bonus index of the carcasses. Therefore, chromium picolinate and chromium yeast are potential substitutes for ractopamine for optimizing the gilts carcass characteristics.

Realizou-se este estudo com o objetivo de avaliar as suplementações de cromo e a restrição energética em substituição a ractopamina para leitoas em terminação tardia. Foram utilizadas 60 leitoas, com pesos inicial de 98,87±0,25 kg e final de 122,69 ± 10,97 kg, distribuídas em delineamento de blocos ao acaso com cinco dietas: controle; cromo levedura (0,8 ppm); picolinato de cromo (0,48 ppm); ractopamina (20 ppm) e restrição energética (redução de 150 kcal de EMkg-1 de ração), com seis repetições e dois animais por unidade experimental. A dieta contendo ractopamina proporcionou melhor (P<0,05) conversão alimentar e maior peso de carcaça quente das leitoas. A dieta contendo ractopamina apresentou menor (P<0,05) custo de ração por quilograma de ganho e maior índice de eficiência econômica em relação as dietas contendo cromo e restrição energética que, por sua vez, foram superiores em comparação a dieta controle. Dietas suplementadas com cromo e ractopamina apresentaram maior (P<0,05) percentual e quantidade de carne magra e maior índice de bonificação de carcaça em relação a dieta controle e restrição energética. Concluiu-se que a redução energética não prejudica as respostas das leitoas em relação a dieta controle. A suplementação de ractopamina possibilita melhor conversão alimentar, menor custo de ração por quilograma de ganho e maior índice de eficiência econômica. As suplementações de cromo e ractopamina expressam aumento do percentual e quantidade de carne magra e do índice de bonificação das carcaças. O picolinato de cromo e o cromo levedura são potenciais substitutos a ractopamina para otimizar as características de carcaça das leitoas.

Magrario: un nuevo genotipo para producir carne ovina de calidad / Magrario: a new genotype to produce quality sheep meat

RESUMEN En la producción de carne ovina en Argentina existe escasa tradición para la comercialización de reses de corderos pesados con bajo tenor de grasa. Un nuevo genotipo cuya marca registrada es Magrario (M) fue obtenido en el Campo Villarino de la Facultad de Ciencias Agrarias de la Universidad Nacional de Rosario (33º S, 61º O) por cruzas absorbentes de una raza tradicional en la zona, Ideal (I) (Polwarth), hacia la raza Texel (raza reconocida por producir reses magras). A partir de la población base de la tercera retrocruza se seleccionó a los machos por el Aumento Medio Diario relativo hasta los tres meses de edad y a las hembras por la fertilidad de sus madres. Se verificaron diferencias significativas en la composición de la res en lo referente a depósitos grasos de este nuevo genotipo respecto a la población fundadora I tanto en confinamiento posdestete durante dos meses como en condiciones de cría a campo. También se compararon en confinamiento corderos M con los de la raza Hampshire Down (HD) siendo los depósitos grasos significativamente superiores en esta última raza. También se analizaron cruzamientos de M con HD e I verificando un efecto semi-dominante del nuevo genotipo para reducir tenor de grasa en las cruzas. La reducción de grasa subcutánea en el Longissimus Dorsi de (MxHD) se redujo un 20%. Esta experiencia demostró que Magrario puede ser utilizado como progenitor en cruzamientos si se desea producir corderos con menores depósitos grasos en condiciones de suplementación posdestete.

ABSTRACT Generally there is poor tradition to produce and to commercialize heavy lean lamb carcasses. To achieve a better product for the ovine meat market Ideal (Polwarth) breed ewes were backcrossed to Texel breed rams (breed recognized to reduce carcass fat). Ideal breed (I) is one of the most ordinary breeds in Argentina. However, when their lambs are reared in feedlot conditions, a high fat content is found in their lamb carcasses. After three generations of backcrosses followed by a breeding program for increase male lamb weaning weight and female fertility a new genotype was obtained for the local ovine meat production systems. This new genotype registered as Magrario (M) was obtained at Villarino Field Station of UNR (Zavalla, Santa Fe, 33º S, 61º W). It was verify that M produced more lean meat than I breed under feet lot conditions. M rams were introduced in flocks of Hampshire Down (HD) breed to evaluate lamb crosses with lean meat. Genotype M was compared under feed lot conditions with HD lambs during two months in the post weaning. Also crosses (MxHD), (MxI) and (IxHD) were evaluated in the same conditions. At the end of the experiment ultrasonic methods were used to evaluate fat depot on Longissimus dorsi. The (MxHD) showed a reduction of 20% respecting to HD. These results suggested that M genotype could be a useful paternal genotype to reduce fat depots when the aim is to produce lamb crosses under feed lot conditions in a short period of time.

Performance, carcass and meat quality of pigs submitted to immunocastration and different feeding programs.

The feed restriction of pigs aims to improve the nutrient utilization of the diet, reduce carcass fat and increase lean meat. Immunocastration is a painless, reversible technique that improves animal welfare, decreases boar taint in meat, leading to lower fat deposition and increases lean meat. This study aimed at evaluating either feeding (restricted) programs (FP) and castration categories (surgically castrated × immunocastration) in terms of pig performance, carcass traits and meat quality. Castration category and FP did not influence marbling, initial pH and drip loss in loin and ham. However, immunocastrated pigs presented lighter loins and hams with lower ultimate pH, compared to the surgically castrated pigs. The FP with lower feed volume resulted in higher ultimate pH. Immunocastrated males had a higher live weight than those surgically castrated. Also, the more the feed supply decreased, the better the feed conversion. Immunocastrates had lower carcass yields, however these pigs had their backfat thickness decreased and lean meat increased in the carcass, without affecting the loin depth.

Effect of ractopamine and conjugated linoleic acid on performance of late finishing pigs.

The dietary inclusion of feed additives to improve the carcass characteristics of the final product is of great importance for the pork production chain. The aim of our study was to evaluate the effects of the association of ractopamine (RAC) and conjugated linoleic acid (CLA) on the performance traits of finishing pigs during the last 26 days prior to slaughter. In total, 810 commercial hybrid barrows were used. Animals were distributed among treatments according to a randomised block design in a 3 × 3 factorial arrangement, with three RAC levels (0, 5 or 10 ppm) and three CLA levels (0, 0.3 or 0.6%). Pigs fed the diet with 5 ppm RAC had higher average daily feed intake (ADFI) (2.83 kg; P < 0.05) when compared with those fed 10 ppm RAC and the control diet (2.75 and 2.74 kg, respectively). Lower ADFI values (P < 0.01) were observed with the diets containing CLA compared with the control diet with no CLA (2.73 and 2.75 v. 2.85 kg/day, respectively). The average daily weight gain of pigs fed 5 and 10 ppm RAC was +148 and +173 g/dayhigher (P < 0.001), respectively, than those fed the control diet. Dietary RAC levels influenced (P < 0.001) feed conversion ratio (FCR), which was reduced as RAC levels increased, with the pigs fed 10, 5 and 0 ppm RAC presenting FCR values of 2.57, 2.71 and 3.05, respectively. FCR also improved (P < 0.05) with the inclusion of 0.6% CLA relative to the control diet (2.70 v. 2.84, respectively). There was a significant interaction between CLA × RAC levels (P < 0.01) for final BW, loin eye area (LEA) (P < 0.05) and backfat thickness (BT) (P < 0.05). The treatments containing 10 ppm RAC + 0.6% or 0.3% CLA increased LEA and reduced BT. In conclusion, the level of 10 ppm inclusion of RAC increased the overall performance parameters of pigs and therefore improved production efficiency. The combined use of RAC and CLA promoted a lower feed conversion ratio as well as better quantitative carcass traits, as demonstrated by the higher LEA and lower BT. The dietary inclusion of CLA at 0.3% improved feed efficiency, however, without affecting LEA or BT yields.

Meat quality of suckling goat raised in differents feeding systems

The objective of this work was to evaluate the effect of three breeding systems on the organoleptic quality and the physico-chemical composition of kids goat meat. Were used thirty newborn baby goats of 3.35 kg ± 0.65 kg crossed Parda Alpina x Undefined Race (SPRD) submitted to three breeding systems: Traditional system-TS; Intensive Feeding System without Concentrate- IS and Intensive Feeding System with Concentrate- IS+C. When the goats reached 12 kg, the animals were slaughtered and chemical and physical analyzes were performed in the evaluation of the meat and sensorial. The experimental design was completely randomized, submitted to analysis of variance and compared by the Tukey test and Ryan-Einot-Gabriel-Welsh at 5%. All analyzed variables were also submitted to Pearson correlation. The meat of the goats submitted to IS+C and IS presented higher intramuscular fat content and better flavor and aroma scores. A of Goats that used concentrated ration (TS and IS+C) showed a more intense red color in the meat than the animals that did not receive concentrate in their diets, besides presenting higher lipid contents in their composition, better scores for these two organoleptic characteristics. The chemical composition of goat meat in both breeding systems indicates that it is low in fat and high in moisture and therefore classified as very tender and juicy. The meat obtained from the IS+C, in general, presented better attributes than the others, believing it in the markets of meat of high quality.(AU)

Meat quality of suckling goat raised in differents feeding systems

The objective of this work was to evaluate the effect of three breeding systems on the organoleptic quality and the physico-chemical composition of kids goat meat. Were used thirty newborn baby goats of 3.35 kg ± 0.65 kg crossed Parda Alpina x Undefined Race (SPRD) submitted to three breeding systems: Traditional system-TS; Intensive Feeding System without Concentrate- IS and Intensive Feeding System with Concentrate- IS+C. When the goats reached 12 kg, the animals were slaughtered and chemical and physical analyzes were performed in the evaluation of the meat and sensorial. The experimental design was completely randomized, submitted to analysis of variance and compared by the Tukey test and Ryan-Einot-Gabriel-Welsh at 5%. All analyzed variables were also submitted to Pearson correlation. The meat of the goats submitted to IS+C and IS presented higher intramuscular fat content and better flavor and aroma scores. A of Goats that used concentrated ration (TS and IS+C) showed a more intense red color in the meat than the animals that did not receive concentrate in their diets, besides presenting higher lipid contents in their composition, better scores for these two organoleptic characteristics. The chemical composition of goat meat in both breeding systems indicates that it is low in fat and high in moisture and therefore classified as very tender and juicy. The meat obtained from the IS+C, in general, presented better attributes than the others, believing it in the markets of meat of high quality.

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

This study was carried out to determine the combining effects of feeding up to 15 mg kg−1 ractopamine (RAC) to physically castrated (PC) pigs or those injected with an anti-GnRF vaccine (IC), on growth performance during suckling, weaning, growing and finishing phases. Out of a total of 1,160 male piglets, 50 % were surgically castrated at age 7, while 50 % underwent immunization against GnRF on the 103rd and 136th day of life. A completely randomized design, with two treatments (PC and IC), was used from the 1st until the 60th day of life. Afterwards, 792 animals, PC and IC, selected according to overall average weight (23.3 ± 0.69 kg) were allotted based on a completely randomized block design with a 2 × 4 factorial arrangement of treatments (castration categories × RAC levels) with 9 replications (11 animals) per main combination effect. IC growing pigs improved feed conversion due to lower average daily feed intake and higher average daily gain (ADG). During the finishing phase, both RAC and immunocastration increased body weight, but the effects were independent. RAC, on its own improved ADG and feed conversion. However, pigs fed 10 mg kg−1 RAC had higher blood lactate compared to those fed lower levels, suggesting that these animals were more susceptible to stress. Muscle depth was influenced only by RAC, whereas fat thickness was lower for IC. Lean meat increased and fat decreased in the shoulder and belly of IC; RAC had a positive effect on belly lean meat only. Either immunocastration or RAC inclusion (at least 5 mg kg−1) promoted muscle gain and fat reduction in pig carcass, adding value to pork.

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

This study was carried out to determine the combining effects of feeding up to 15 mg kg−1 ractopamine (RAC) to physically castrated (PC) pigs or those injected with an anti-GnRF vaccine (IC), on growth performance during suckling, weaning, growing and finishing phases. Out of a total of 1,160 male piglets, 50 % were surgically castrated at age 7, while 50 % underwent immunization against GnRF on the 103rd and 136th day of life. A completely randomized design, with two treatments (PC and IC), was used from the 1st until the 60th day of life. Afterwards, 792 animals, PC and IC, selected according to overall average weight (23.3 ± 0.69 kg) were allotted based on a completely randomized block design with a 2 × 4 factorial arrangement of treatments (castration categories × RAC levels) with 9 replications (11 animals) per main combination effect. IC growing pigs improved feed conversion due to lower average daily feed intake and higher average daily gain (ADG). During the finishing phase, both RAC and immunocastration increased body weight, but the effects were independent. RAC, on its own improved ADG and feed conversion. However, pigs fed 10 mg kg−1 RAC had higher blood lactate compared to those fed lower levels, suggesting that these animals were more susceptible to stress. Muscle depth was influenced only by RAC, whereas fat thickness was lower for IC. Lean meat increased and fat decreased in the shoulder and belly of IC; RAC had a positive effect on belly lean meat only. Either immunocastration or RAC inclusion (at least 5 mg kg−1) promoted muscle gain and fat reduction in pig carcass, adding value to pork.(AU)

Levels of digestible lysine in diets with ractopamine for finishing pigs / Níveis de lisina digestível em dietas contendo ractopamina para suínos em terminação

The objective was to evaluate levels of digestible lysine in diets with 5ppm of ractopamine on performance and carcass characteristics of finishing pigs. Ninety-six pigs, 48 barrows and gilts with initial body weight of 83.57 ± 4.07kg, were sorted in a complete randomized design with four levels of digestible lysine (0.94; 0.96; 1.02 e 1.04%), with three replications and eight animals each. The experimental period lasted 28 days. The feed intake was reduced and feed:gain ration improved linearly with increase digestible lysine levels in diets. Final, slaughter and hot carcass weights, carcass yield, amount of lean meat and payment index increase linearly with increase of digestible lysine levels. There was no effect of digestible lysine levels on daily gain, farm to slaughter shrink and lean meat percent. In conclusion, in diets with 5 ppm ractopamine, 1.04% digestible lysine improve feed:gain ration and increase final weight, carcass weight and yield, amount of lean meat and payment index of carcass of pigs.

Objetivou-se avaliar níveis de lisina digestível em dietas contendo 5 ppm de ractopamina sobre o desempenho e características quantitativas de carcaça de suínos em fase de terminação. Foram utilizados 96 suínos, sendo 48 machos castrados e 48 fêmeas, com peso inicial de 83,57 ± 4,07kg, distribuídos em delineamento inteiramente ao acaso, com quatro níveis de lisina digestível (0,94; 0,96; 1,02 e 1,04%), com três repetições de oito animais cada. O período experimental teve duração de 28 dias. O consumo de ração diário reduziu e a conversão alimentar melhorou linearmente de acordo com o aumento dos níveis de lisina digestível das dietas. Os pesos final, de frigorífico e de carcaça quente, o rendimento de carcaça, a quantidade de carne magra e o índice de bonificação aumentaram linearmente de acordo com o aumento dos níveis de lisina digestível. Não houve efeito dos níveis de lisina digestível sobre o ganho de peso diário, perda de peso durante o transporte e a porcentagem de carne magra da carcaça. Concluiu-se que, em dietas contendo 5ppm de ractopamina, o nível de 1,04% de lisina digestível melhora a conversão alimentar e aumenta o peso final, o peso e o rendimento de carcaça, a quantidade de carne magra e o índice de bonificação das carcaças dos suínos.

Levels of digestible lysine in diets with ractopamine for finishing pigs / Níveis de lisina digestível em dietas contendo ractopamina para suínos em terminação

The objective was to evaluate levels of digestible lysine in diets with 5ppm of ractopamine on performance and carcass characteristics of finishing pigs. Ninety-six pigs, 48 barrows and gilts with initial body weight of 83.57 ± 4.07kg, were sorted in a complete randomized design with four levels of digestible lysine (0.94; 0.96; 1.02 e 1.04%), with three replications and eight animals each. The experimental period lasted 28 days. The feed intake was reduced and feed:gain ration improved linearly with increase digestible lysine levels in diets. Final, slaughter and hot carcass weights, carcass yield, amount of lean meat and payment index increase linearly with increase of digestible lysine levels. There was no effect of digestible lysine levels on daily gain, farm to slaughter shrink and lean meat percent. In conclusion, in diets with 5 ppm ractopamine, 1.04% digestible lysine improve feed:gain ration and increase final weight, carcass weight and yield, amount of lean meat and payment index of carcass of pigs.(AU)

Objetivou-se avaliar níveis de lisina digestível em dietas contendo 5 ppm de ractopamina sobre o desempenho e características quantitativas de carcaça de suínos em fase de terminação. Foram utilizados 96 suínos, sendo 48 machos castrados e 48 fêmeas, com peso inicial de 83,57 ± 4,07kg, distribuídos em delineamento inteiramente ao acaso, com quatro níveis de lisina digestível (0,94; 0,96; 1,02 e 1,04%), com três repetições de oito animais cada. O período experimental teve duração de 28 dias. O consumo de ração diário reduziu e a conversão alimentar melhorou linearmente de acordo com o aumento dos níveis de lisina digestível das dietas. Os pesos final, de frigorífico e de carcaça quente, o rendimento de carcaça, a quantidade de carne magra e o índice de bonificação aumentaram linearmente de acordo com o aumento dos níveis de lisina digestível. Não houve efeito dos níveis de lisina digestível sobre o ganho de peso diário, perda de peso durante o transporte e a porcentagem de carne magra da carcaça. Concluiu-se que, em dietas contendo 5ppm de ractopamina, o nível de 1,04% de lisina digestível melhora a conversão alimentar e aumenta o peso final, o peso e o rendimento de carcaça, a quantidade de carne magra e o índice de bonificação das carcaças dos suínos.(AU)

Carcass characteristics and qualitative attributes of pork from immunocastrated animals.

An investigation was carried out to assess the carcass characteristics and meat quality aspects of immunocastrated male pigs of medium genetic potential for lean meat deposition in carcass (53 to 55%). When the crossbred Large White x Landrace pigs (n = 45) were 70 days old, they were distributed in a totally randomized design in three treatments (castrated males, females and immunocastrated males) with three replicates of five animals. The pigs were slaughtered when they were 140 days old. Carcass temperature and pH were recorded twice, at 45 min and 24 h after slaughter. The carcasses were evaluated for hot and cold carcass yield, commercial cuts yield, length and depth, back fat thickness, loin eye area and lean meat percentage. The Longissimus dorsi muscle was extracted for analysis of color (L*, a*, b*), exudate loss, cooking loss and centesimal and sensorial analysis of the meat. There were no significant differences for the evaluated parameters between castrated males, immunocastrated males and females, except for backfat thickness between the 7th and 8th thoracic vertebra and the point P2 (lower for immunocastrated males) and carcass temperature at 45 min post slaughter (higher in immunocastrated males), however, this did not interfer with the rate of pH decrease post mortem and the meat quality. The results from this research did not indicate a benefit of immunocastration on carcass characteristics of pigs of medium genetic potential for lean meat deposition in carcass, when compared to surgical castration.

Restrição alimentar para suínos machos castrados e imunocastrados em terminação

The objective of this study was to evaluate the performance and carcass quantitative characteristics of barrows and immunocastrated swine fed ad libitum or under quantitative feeding restriction. Two hundred and forty animals were used, with initial weight of 91.49±3.26kg, distributed in a randomized blocks design, in a factorial scheme 2x2 (two management and two food categories), with four replicates of 15 pigs each. Pigs submitted to dietary restriction had lower consumption (P 0.05) than those fed ad libitum. Feed intake did not differ (P>0.05) between castrated and immunocastrated. Pigs fed ad libitum had higher (P 0.05) weight gain over those submitted to restriction. The immunocastrated showed higher weight gain (P 0.05) than castrated. There was an interaction (P 0.05) between management and categories for feed, in which the restriction improved castrated pigs. Immunocastrated had better (P 0.05) feed conversion compared to castrated, regardless of feed management. There was no interaction (P>0.05) among the factors on carcass traits. The restriction did not affect (P>0.05) carcass traits. Immunocastrated pigs had lower (P 0.05) back fat thickness and higher percentage of lean meat. Dietary restriction improves feed conversion of castrated pigs. The dietary restriction affects weight gain and does not affect carcass characteristics of barrows and immunocastrated. Immunocastrated pigs have higher performance, lower back fat thickness and a higher percentage of lean meat compared to the castrated.

O objetivo do trabalho foi avaliar o desempenho e as características quantitativas de carcaça de suínos machos castrados e imunocastrados, sob alimentação à vontade ou restrição quantitativa. Foram utilizados 240 animais, com peso inicial de 91,49±3,26kg, distribuídos em delineamento experimental de blocos ao acaso, em esquema fatorial 2x2 (dois manejos alimentares e duas categorias), com quatro repetições e 15 suínos cada. Suínos sob restrição alimentar apresentaram consumo inferior (P 0,05) em relação aos alimentados à vontade. O consumo de ração não diferiu (P>0,05) entre castrados e imunocastrados. Suínos alimentados à vontade apresentaram maior (P 0,05) ganho de peso em relação àqueles sob restrição. Os imunocastrados apresentaram ganho de peso superior (P 0,05) aos castrados. Houve interação (P 0,05) entre manejo e categorias para conversão alimentar, em que a restrição melhorou a conversão alimentar dos castrados em relação aos imunocastrados. Além disso, os imunocastrados apresentaram melhor (P 0,05) conversão alimentar em relação aos castrados, independente do manejo alimentar. Não houve interação (P>0,05) entre os fatores sobre as características de carcaça. A restrição não afetou (P>0,05) as características de carcaça. Machos imunocastrados apresentaram menor (P 0,05) espessura de toucinho e maior percentual de carne magra na carcaça. A restrição alimentar melhora a conversão alimentar de machos castrados. A restrição alimentar piora o ganho de peso e não altera as características de carcaça dos machos castrados e imunocastrados. Suínos imunocastrados apresentam desempenho superior, menor espessura de toucinho e maior percentual de carne magra em relação aos castrados.

Restrição alimentar para suínos machos castrados e imunocastrados em terminação

The objective of this study was to evaluate the performance and carcass quantitative characteristics of barrows and immunocastrated swine fed ad libitum or under quantitative feeding restriction. Two hundred and forty animals were used, with initial weight of 91.49±3.26kg, distributed in a randomized blocks design, in a factorial scheme 2x2 (two management and two food categories), with four replicates of 15 pigs each. Pigs submitted to dietary restriction had lower consumption (P 0.05) than those fed ad libitum. Feed intake did not differ (P>0.05) between castrated and immunocastrated. Pigs fed ad libitum had higher (P 0.05) weight gain over those submitted to restriction. The immunocastrated showed higher weight gain (P 0.05) than castrated. There was an interaction (P 0.05) between management and categories for feed, in which the restriction improved castrated pigs. Immunocastrated had better (P 0.05) feed conversion compared to castrated, regardless of feed management. There was no interaction (P>0.05) among the factors on carcass traits. The restriction did not affect (P>0.05) carcass traits. Immunocastrated pigs had lower (P 0.05) back fat thickness and higher percentage of lean meat. Dietary restriction improves feed conversion of castrated pigs. The dietary restriction affects weight gain and does not affect carcass characteristics of barrows and immunocastrated. Immunocastrated pigs have higher performance, lower back fat thickness and a higher percentage of lean meat compared to the castrated.

O objetivo do trabalho foi avaliar o desempenho e as características quantitativas de carcaça de suínos machos castrados e imunocastrados, sob alimentação à vontade ou restrição quantitativa. Foram utilizados 240 animais, com peso inicial de 91,49±3,26kg, distribuídos em delineamento experimental de blocos ao acaso, em esquema fatorial 2x2 (dois manejos alimentares e duas categorias), com quatro repetições e 15 suínos cada. Suínos sob restrição alimentar apresentaram consumo inferior (P 0,05) em relação aos alimentados à vontade. O consumo de ração não diferiu (P>0,05) entre castrados e imunocastrados. Suínos alimentados à vontade apresentaram maior (P 0,05) ganho de peso em relação àqueles sob restrição. Os imunocastrados apresentaram ganho de peso superior (P 0,05) aos castrados. Houve interação (P 0,05) entre manejo e categorias para conversão alimentar, em que a restrição melhorou a conversão alimentar dos castrados em relação aos imunocastrados. Além disso, os imunocastrados apresentaram melhor (P 0,05) conversão alimentar em relação aos castrados, independente do manejo alimentar. Não houve interação (P>0,05) entre os fatores sobre as características de carcaça. A restrição não afetou (P>0,05) as características de carcaça. Machos imunocastrados apresentaram menor (P 0,05) espessura de toucinho e maior percentual de carne magra na carcaça. A restrição alimentar melhora a conversão alimentar de machos castrados. A restrição alimentar piora o ganho de peso e não altera as características de carcaça dos machos castrados e imunocastrados. Suínos imunocastrados apresentam desempenho superior, menor espessura de toucinho e maior percentual de carne magra em relação aos castrados.

Restrição alimentar para suínos machos castrados e imunocastrados em terminação / Feeding restriction to finishing barrows and immunocastrated swine

O objetivo do trabalho foi avaliar o desempenho e as características quantitativas de carcaça de suínos machos castrados e imunocastrados, sob alimentação à vontade ou restrição quantitativa. Foram utilizados 240 animais, com peso inicial de 91,49±3,26kg, distribuídos em delineamento experimental de blocos ao acaso, em esquema fatorial 2x2 (dois manejos alimentares e duas categorias), com quatro repetições e 15 suínos cada. Suínos sob restrição alimentar apresentaram consumo inferior (P<0,05) em relação aos alimentados à vontade. O consumo de ração não diferiu (P>0,05) entre castrados e imunocastrados. Suínos alimentados à vontade apresentaram maior (P<0,05) ganho de peso em relação àqueles sob restrição. Os imunocastrados apresentaram ganho de peso superior (P<0,05) aos castrados. Houve interação (P<0,05) entre manejo e categorias para conversão alimentar, em que a restrição melhorou a conversão alimentar dos castrados em relação aos imunocastrados. Além disso, os imunocastrados apresentaram melhor (P<0,05) conversão alimentar em relação aos castrados, independente do manejo alimentar. Não houve interação (P>0,05) entre os fatores sobre as características de carcaça. A restrição não afetou (P>0,05) as características de carcaça. Machos imunocastrados apresentaram menor (P<0,05) espessura de toucinho e maior percentual de carne magra na carcaça. A restrição alimentar melhora a conversão alimentar de machos castrados. A restrição alimentar piora o ganho de peso e não altera as características de carcaça dos machos castrados e imunocastrados. Suínos imunocastrados apresentam desempenho superior, menor espessura de toucinho e maior percentual de carne magra em relação aos castrados.

The objective of this study was to evaluate the performance and carcass quantitative characteristics of barrows and immunocastrated swine fed ad libitum or under quantitative feeding restriction. Two hundred and forty animals were used, with initial weight of 91.49±3.26kg, distributed in a randomized blocks design, in a factorial scheme 2x2 (two management and two food categories), with four replicates of 15 pigs each. Pigs submitted to dietary restriction had lower consumption (P<0.05) than those fed ad libitum. Feed intake did not differ (P>0.05) between castrated and immunocastrated. Pigs fed ad libitum had higher (P<0.05) weight gain over those submitted to restriction. The immunocastrated showed higher weight gain (P<0.05) than castrated. There was an interaction (P<0.05) between management and categories for feed, in which the restriction improved castrated pigs. Immunocastrated had better (P <0.05) feed conversion compared to castrated, regardless of feed management. There was no interaction (P>0.05) among the factors on carcass traits. The restriction did not affect (P>0.05) carcass traits. Immunocastrated pigs had lower (P<0.05) back fat thickness and higher percentage of lean meat. Dietary restriction improves feed conversion of castrated pigs. The dietary restriction affects weight gain and does not affect carcass characteristics of barrows and immunocastrated. Immunocastrated pigs have higher performance, lower back fat thickness and a higher percentage of lean meat compared to the castrated.

Simulação técnico-econômica da inclusão de ractopamina em dietas de suínos em terminação / Technical-economic simulation of ractopamine inclusion in diets for finishing pigs

Foi realizada simulação técnico-econômica a partir de resultados de publicações para avaliar a inclusão de ractopamina em dietas de suínos em terminação. Foram utilizados 18 artigos, que avaliaram níveis de 0, 5, 10 e/ou 20ppm de ractopamina na dieta, totalizando 2.991 animais. A partir dos resultados técnicos das publicações avaliadas, foram geradas equações que foram utilizadas na simulação do desempenho técnico-econômico. Verificou-se que os custos independem do sistema de receitas do produtor e oscilam de 3 a 6ppm de ractopamina adicionada à dieta. O lucro máximo foi obtido com os níveis de 10 e 12ppm de ractopamina, respectivamente, para os sistemas de receita por peso vivo e por bonificação. Os resultados evidenciam melhor desempenho econômico da utilização de ractopamina, na dieta dos suínos em terminação, pelo sistema de receita por bonificação. As análises de sensibilidade para a variação na receita dos produtores apresentam valores ótimos de 9 a 12ppm de ractopamina, com oscilação de até R$ 49,00/cabeça entre os cenários testados.(AU)

A technical-economic simulation was performed based on results from publications for assessing the inclusion of ractopamine in the diet of finishing pigs. Eighteen articles were used, which assessed levels of 0, 5, 10, and/or 20ppm of ractopamine in the diet, totalizing 2,991 animals. Based on the results obtained in these technical publications, equations were used for the simulation of the technical-economic performance. From this study, it was established that the costs are independent of the system of revenue of the producer and range from 3 to 6ppm of ractopamine added in the diet. The maximum profit was obtained with the levels of 10 and 12ppm of ractopamine, respectively, for the systems of revenue per body weight and per bonus. The results show a better economic performance with the use of ractopamine in the diet of finishing pigs, by the system of revenue per bonus. Analyses of sensitivity of changes in the revenue of producers presented optimal values of 9 to 12ppm of ractopamine, with a range of up to R$ 49.00 per capita between the tested scenarios.(AU)

Simulação técnico-econômica da inclusão de ractopamina em dietas de suínos em terminação / Technical-economic simulation of ractopamine inclusion in diets for finishing pigs

Foi realizada simulação técnico-econômica a partir de resultados de publicações para avaliar a inclusão de ractopamina em dietas de suínos em terminação. Foram utilizados 18 artigos, que avaliaram níveis de 0, 5, 10 e/ou 20ppm de ractopamina na dieta, totalizando 2.991 animais. A partir dos resultados técnicos das publicações avaliadas, foram geradas equações que foram utilizadas na simulação do desempenho técnico-econômico. Verificou-se que os custos independem do sistema de receitas do produtor e oscilam de 3 a 6ppm de ractopamina adicionada à dieta. O lucro máximo foi obtido com os níveis de 10 e 12ppm de ractopamina, respectivamente, para os sistemas de receita por peso vivo e por bonificação. Os resultados evidenciam melhor desempenho econômico da utilização de ractopamina, na dieta dos suínos em terminação, pelo sistema de receita por bonificação. As análises de sensibilidade para a variação na receita dos produtores apresentam valores ótimos de 9 a 12ppm de ractopamina, com oscilação de até R$ 49,00/cabeça entre os cenários testados.

A technical-economic simulation was performed based on results from publications for assessing the inclusion of ractopamine in the diet of finishing pigs. Eighteen articles were used, which assessed levels of 0, 5, 10, and/or 20ppm of ractopamine in the diet, totalizing 2,991 animals. Based on the results obtained in these technical publications, equations were used for the simulation of the technical-economic performance. From this study, it was established that the costs are independent of the system of revenue of the producer and range from 3 to 6ppm of ractopamine added in the diet. The maximum profit was obtained with the levels of 10 and 12ppm of ractopamine, respectively, for the systems of revenue per body weight and per bonus. The results show a better economic performance with the use of ractopamine in the diet of finishing pigs, by the system of revenue per bonus. Analyses of sensitivity of changes in the revenue of producers presented optimal values of 9 to 12ppm of ractopamine, with a range of up to R$ 49.00 per capita between the tested scenarios.

Lysine requirement of starting barrows from two genetic groups fed on low crude protein diets

A trial was carried out to determine the lysine requirement for starting barrows fed on ideal protein concept-based diets. Thirty-two pigs from a commercial crossbred genetic group (CCGG, BW=15.9 ± 1.4 kg) and 32 pigs from a dam line one (DLGG, BW= 14.8 ± 1.0 kg) were used. Pigs were allotted to 4 treatments with diets containing increasing levels of total lysine (0.80, 1.00, 1.20 and 1.40 percent). Methionine+cystine, threonine and tryptophan were adjusted according to ideal protein profile. Data from performance, plasma urea nitrogen (PUN) and carcass composition were analyzed. CCGG showed higher daily feed intake, daily weight gain, PUN and protein:fat ratio in carcass, while DLGG showed higher fat carcass content and nitrogen retention. Fat content and protein:fat ratio in carcass for CCCGG and PUN and crude protein carcass content for DLGG showed quadratic response to increasing total lysine levels. Derivations of the quadratic equations indicated the total lysine requirement for CCGG starting barrows is 1.15 percent and for DLGG starting barrows is 1.09 percent.

Foi realizado um trabalho com o objetivo de determinar a exigência em lisina para suínos castrados em fase inicial, alimentados com dietas formuladas de acordo com o conceito de proteína ideal. Trinta e dois suínos provenientes de cruzamento comercial (CC, PV = 15,9 kg) e 32 suínos provenientes de linhagem materna (LM, PV= 14,8 kg) foram alimentados com quatro dietas contendo níveis crescentes de lisina total (0,80; 1,00; 1,20 e 1,40 por cento). Metionina + cistina, triptofano e treonina foram adicionados às dietas para manter constante o padrão de proteína ideal. Foram analisados dados de desempenho, nitrogênio da uréia plasmática (NUP) e carcaça. Suínos do grupo CC apresentaram maior consumo diário de ração, ganho diário de peso, NUP e relação proteína: gordura na carcaça, enquanto que os animais do grupo LM apresentaram maiores teores de gordura na carcaça e retenção de nitrogênio. Teor de gordura e relação proteína:gordura na carcaça para o grupo CC e NUP e teor de proteína bruta na carcaça para o grupo LM apresentaram resposta quadrática aos níveis de lisina. Derivações das equações indicaram a exigência de lisina total de suínos machos castrados do grupo cruzamento industrial de 1,15 por cento e do grupo linhagem materna de 1,09 por cento.

Efeitos do incremento de fibra dietética sobre a digestibilidade, desempenho e características de carcaça: I. suínos em crescimento e terminação1 / Effects of increasing dietary fiber on digestibility, performance andcarcass characteristics: I. growing and finishing gilts

Objetivando avaliar os efeitos de ração fibrosa sobre parâmetros de digestibilidade dos nutrientes, dedesempenho produtivo e de características de carcaça, realizou-se o presente experimento, utilizando 24suínos mestiços, durante as fases de crescimento e terminação, em delineamento blocos inteiramentecasualizados. Os animais foram alimentados à vontade com rações isonutrientes contendo incrementosde 0 ou 8% de fibra em detergente neutro (FDN), obtidas através da inclusão de 0 ou 10% de feno de“coast-cross” (Cynodon dactylon). Na fase de crescimento, os tratamentos diferiram para a digestibilidadeda matéria seca, energia bruta, proteína bruta e fibra em detergente ácido com piora nos valores para aração com 8% de FDN. Na fase de terminação, houve diferença na digestibilidade para matéria seca,energia bruta, proteína bruta, fibra em detergente neutro e fibra em detergente ácido com redução nosíndices para a ração com 8% de FDN. A inclusão de 8% de FDN não alterou o peso corporal final, ganhode peso, conversão alimentar, rendimentos de carcaças quente e fria, rendimento de carne magra e áreade olho de lombo. Os resultados indicaram que o contínuo oferecimento de relativamente baixo teor deFDN alterou a digestibilidade dos componentes dietéticos da ração. Entretanto, como os parâmetrosreferentes ao desempenho animal e às características de carcaça não foram comprometidos, vislumbrasereal possibilidade de emprego de moderadas quantidades de materiais fibrosos na alimentação desuínos, nas fases de crescimento e terminação.

This work aimed to evaluate the effects of fibrous ration on parameters of nutrient digestibility, animal performance and carcass characteristics, using 24 crossbred gilts during growing and finishing phases in a completely randomized design experiment. The animals were fed ad libitum with isonutrients rations containing increments of 0 or 8% neutral detergent fiber (NDF), obtained through the inclusion of 0 or 10% coast cross grass hay (Cynodon dactylon). In the growing phase, treatments were different for dry matter, energy, crude protein and acid detergent fiber digestibilities with worsening in the valuesfor ration with 8% NDF. In the finishing phase, differences were detected on digestibility of dry matter, energy, crude protein, neutral detergent fiber and acid detergent fiber with reduction on the rate for the ration with 8% of NDF. The inclusion of 8% NDF had no effect upon final body weight, weight gain, feed conversion, yield of hot and chilled carcass, yield of lean meat and loin eye area. The results pointed out that continuous feeding of relatively low content of NDF altered the digestibility of dietary components of the meal. However, as animal performance and carcass characteristics were not compromised, it can be foreseen that moderate quantities of fibrous feedstuff can actually be used for feeding of gilts during the growing and finishing phases.

Effects of increasing dietary fiber on digestibility, performance and carcass characteristics: I. growing and finishing gilts / Efeitos do incremento de fibra dietética sobre a digestibilidade, desempenho e características de carcaça: I. suínos em crescimento e terminação

This work aimed to evaluate the effects of fibrous ration on parameters of nutrient digestibility, animal performance and carcass characteristics, using 24 crossbred gilts during growing and finishing phases in a completely randomized design experiment. The animals were fed ad libitum with isonutrients rations containing increments of 0 or 8% neutral detergent fiber (NDF), obtained through the inclusion of 0 or 10% coast cross grass hay (Cynodon dactylon). In the growing phase, treatments were different for dry matter, energy, crude protein and acid detergent fiber digestibilities with worsening in the valuesfor ration with 8% NDF. In the finishing phase, differences were detected on digestibility of dry matter, energy, crude protein, neutral detergent fiber and acid detergent fiber with reduction on the rate for the ration with 8% of NDF. The inclusion of 8% NDF had no effect upon final body weight, weight gain, feed conversion, yield of hot and chilled carcass, yield of lean meat and loin eye area. The results pointed out that continuous feeding of relatively low content of NDF altered the digestibility of dietary components of the meal. However, as animal performance and carcass characteristics were not compromised, it can be foreseen that moderate quantities of fibrous feedstuff can actually be used for feeding of gilts during the growing and finishing phases.

Objetivando avaliar os efeitos de ração fibrosa sobre parâmetros de digestibilidade dos nutrientes, de desempenho produtivo e de características de carcaça, realizou-se o presente experimento, utilizando 24 suínos mestiços, durante as fases de crescimento e terminação, em delineamento blocos inteiramente casualizados. Os animais foram alimentados à vontade com rações isonutrientes contendo incrementos de 0 ou 8% de fibra em detergente neutro (FDN), obtidas através da inclusão de 0 ou 10% de feno de coast-cross (Cynodon dactylon). Na fase de crescimento, os tratamentos diferiram para a digestibilidade da matéria seca, energia bruta, proteína bruta e fibra em detergente ácido com piora nos valores para a ração com 8% de FDN. Na fase de terminação, houve diferença na digestibilidade para matéria seca, energia bruta, proteína bruta, fibra em detergente neutro e fibra em detergente ácido com redução nos índices para a ração com 8% de FDN. A inclusão de 8% de FDN não alterou o peso corporal final, ganho de peso, conversão alimentar, rendimentos de carcaças quente e fria, rendimento de carne magra e área de olho de lombo. Os resultados indicaram que o contínuo oferecimento de relativamente baixo teor de FDN alterou a digestibilidade dos componentes dietéticos da ração. Entretanto, como os parâmetros referentes ao desempenho animal e às características de carcaça não foram comprometi