Charles Kiefer

Resposta de suínos em crescimento mantidos em diferentes temperaturas

portuguesForam utilizados 24 suinos machos castrados, distribuidos em delineamento inteiramente ao acaso composto por dois tratamentos e doze repeticoes, com o objetivo de avaliar o compor-tamento, respostas fisiologicas e o desempenho dos animais. As temperaturas medias do periodo experimental foram 21,5°C e 31,3°C, respectivamente, nos ambientes de conforto termico e de estresse por calor. Suinos sob estresse por calor permaneceram significativamente menos tempo na posicao em pe, mais tempo na posicao deitado, menos tempo no comedouro, mais tempo no bebedouro, mais tempo na posicao deitado no bebedouro e mais tempo dormindo em relacao aqueles mantidos sob conforto termico. Suinos sob estresse por calor apresentaram consumos de energia, proteina, lisina e racao, ganho de peso e conversao alimentar reduzidos e apresentaram menores pesos de orgaos, exceto do estomago, e frequencia respiratoria e temperaturas retal e de superficie aumentadas. Suinos sob conforto termico apresentaram maior eficiencia de utilizacao da proteina e energia e maiores deposicoes diarias de proteina e gordura na carcaca. Temperaturas que provocam estresse por calor afetam negativamente o comportamento de suinos em crescimento. EnglishWere used 24 castrated swine distributed in completely randomized design composed for two treatments and twelve repetitions, with the objective to evaluate the behavior, physiological responses and the performance of the animals. The average temperatures of the experimental period were 21.5°C and 31.3°C, respectively, in thermal comfort and heat stress. Swine under heat stress remain significantly little time in the position in foot, more time in the lying position, little time in the feeder, more time in the water through, more time in the lying position in the water through and more time sleeping in relation to those kept in thermal comfort. Swine under heat stress had presented energy, protein, lysine and ration intake, weight gain and feed: gain ratio reduced and had presented minor weight of organs, except of the stomach, and had presented increased respiratory frequency and rectal and surface temperatures. Swine under thermal comfort had presented greater efficiency of use of the protein and energy and greater daily protein and fat depositions in the carcass. Temperatures that provoke heat stress affects negatively the behavior of growing swine.

Níveis de ractopamina para suínos machos castrados em terminação e mantidos sob conforto térmico

The objective of this study was to evaluate the performance and the quantitative characteristics of barrows carcass maintained under thermoneutral environment and fed with diets containing different ractopamine levels. Forty-eight barrows were used, with initial weight of 67.0±2.7kg, distributed in a randomized blocks design with four ractopamine levels (0, 5, 10 and 20ppm) and six replicates with two animals each. The experimental period lasted 28 days. The average temperature recorded was 20.9±2.9°C, relative humidity was 86.7±7.3% and BGHI was 69.6±4.0. The final weight of the animals and feed intake were not influenced (P>0.05) by treatments. The ractopamine levels influenced (P 0.05) by treatments. It was concluded that the ractopamine optimal level of inclusion in the diet of barrows kept under thermoneutral environment is 20ppm.

Meta-analysis of the ractopamine levels in diets for finishing pigs

A meta-analytical study was conducted to evaluate the performance and characteristics of the carcass of finishing pigs fed with diets containing ractopamine. Eighteen experiments containing four treatments and 2.991 animals were used. The treatments were composed of 0, 5, 10 and 20 ppm of ractopamine levels. The variables of performance and the quantitative characteristics of the carcass were analyzed. The average duration of the experimental periods was 28 ± 0.32 days. The average initial and final weights were 74.7 ± 10.9 kg and 107.6 ± 9.7 kg, respectively. No effect of ractopamine levels on the feed intake, hot carcass weight, carcass length and backfat depth was observed. The ractopamine levels influenced the weight gain, the feed:gain ratio, the dressing percent, the lean meat percentage of the carcass and the loin eye area. A linear effect was verified from the lysine levels of the weight gain, gain:feed ratio, hot carcass weight, backfat depth and lean meat percentage of pigs feed diet with 20 ppm of ractopamine. Effect from the loin eye area in function from the lysine levels in the diets containing 10 and 20 ppm of ractopamine was observed. Most of the variables was not influenced by the lysine levels. Levels of 15 ppm of ractopamine optimize the swine performance, while levels of 20 ppm of ractopamine optimize the quantitative carcass characteristics. Weight gain, backfat depth and lean meat carcass percent of swine fed diets containing ractopamine are optimized with 1.0% of true digestible lysine.

Níveis de ractopamina para suínos machos castrados em terminação mantidos sob estresse por calor

Avaliaram-se o desempenho, as caracteristicas quantitativas de carcaca e as respostas viscerais de suinos machos castrados mantidos em ambiente de estresse por calor e alimentados com dietas suplementadas com ractopamina. Foram utilizados 48 animais com peso inicial de 67,3 ± 3,8 kg, distribuidos em delineamento em blocos casualizados, com quatro niveis de ractopamina (0, 5, 10 e 20 mg/kg), cada um com seis repeticoes de dois animais. O periodo experimental foi de 28 dias. A temperatura do ar foi de 31,8 ± 2,0oC, a umidade relativa foi de 72,6 ± 10,2% e indice de temperatura de globo e umidade (ITGU) de 82,7 ± 2,8. Os niveis de ractopamina nao influenciaram o consumo diario de racao, mas melhoraram a conversao alimentar e aumentaram o ganho diario de peso e o peso final dos animais. As caracteristicas quantitativas de carcaca nao foram influenciadas pelos niveis de ractopamina. Os pesos de figado e dos rins aumentaram de forma linear de acordo com os niveis de ractopamina nas dietas, ao passo que o peso dos demais orgaos e o comprimento do intestino delgado nao foram afetados pela suplementacao com ractopamina. O nivel otimo de ractopamina para melhor desempenho de suinos machos castrados sob estresse por calor e de 20 mg/kg e nao altera as caracteristicas quantitativas da carcaca.

Ractopamina em dietas para suínos machos imunocastrados, castrados e fêmeas

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) 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.

Energia líquida e ractopamina para leitoas em terminação sob altas temperaturas ambientais

The objective of this paper was to assess net energy (NE) levels and ractopamine in the diet of finishing gilts maintained under high temperature environment (29.5±2.3°C). Forty gilts were used, with initial weight of 69.3±2.8kg, distributed in a randomized block design, in a factorial scheme 2x4 (0 and 20ppm of ractopamine; and 2,300; 2,424; 2,548 and 2,668kcal/kg NE kg-1 of feed), and five replications and one animal each. There was interaction (P<0.05) between NE levels and ractopamine, and the inclusion of 20ppm of ractopamine in the diets containing 2,548 and 2,668kcal reduced (P<0.05) backfat thickness and increased (P<0.05) the percentage of lean meat of carcasses. The use of ractopamine improved (P<0.05) feed gain ratio and increased (P<0.05) the amount of lean meat in carcasses. It was concluded that ractopamine at a dose of 20ppm provides benefits in performance and carcass traits of gilts under heat stress and this effect is more positive in diets containing higher energy levels (2,548 and 2,668kcal of NE kg-1).

Exigência de metionina mais cistina digestíveis para suínos machos castrados mantidos em ambiente de alta temperatura dos 30 aos 60 kg

Fifty barrows (30.10 ± 0.48 kg to 60.08 ± 0.49 kg live weight were assigned to a completely randomized blocks design, with five digestible methionine plus cystine levels (0.448, 0.490, 0.531, 0.573, and 0.615%), five replicates and two animals per experimental unit, to evaluate the requirement of digestible methionine plus cystine The digestible methionine and cystine levels of the diet influenced the average daily gain that increased in a linear way. However, the linear response plateau model was what best adjusted the data that stabilized in a plateau starting from the level of 0.527% of digestible methionine plus cystine. The feed:gain ratio decreased in a quadratic way with the treatments, until the estimated level of 0.551%. It was not observed the effect of the treatments on the feed intake. The digestible methionine plus cystine intake increased linearly with the increase digestible methionine plus cystine levels in the diet. Effect of the treatments was verified on the protein deposition that increased quadraticaly until the level of 0.551%, while no effect was observed on fat deposition. It was concluded that digestible methionine plus cystine requirements for barrows maintained in high environmental temperature from 30 until the 60 kg are 0.527 and 0.551% of diet, correspondent to digestible methionine plus cystine:digestible lysine ratio of 63.5 and 66%, respectively, to highest weight gain and better feed:gain ratio and highest protein deposition in the carcass.

Lisina digestível em dietas de baixa proteína para frangos de corte tipo caipira de um aos 28 dias

The inclusion of different percentages of digestible lysine in low-protein diets was evaluated for male and female free-range broiler chickens, from 1 to 28 days. We used 792 female and 792 male naked neck chickens a day in a completely randomized 2x6 factorial scheme (sex x percentages of digestible lysine: 0.85, 0.90, 0.95, 1.00, 1.05 and1.10%) with six replicates of 22 broilers. No interaction of sex versus lysine was found. Superiority was observed (P 0.05) in food conversion.In the chemical composition of the carcass, only thepercentage of mineral matter was influenced (P<0.05) bydigestible lysine levels.It was concluded that the level of 0.85% for type redneck broiler meets the nutritional requirement of digestible lysine in diets containing lower protein concentrations.

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) between castrated and immunocastrated. Pigs fed ad libitum had higher (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.

Níveis de energia líquida e ractopamina para leitoas em terminação sob conforto térmico

This research was conducted to evaluate the net energy and ractopamine levels in the diet of finishing gilts kept under thermal comfort conditions. Forty gilts were used, with initial weight of 67.4 ± 3.4 kg, distributed in a randomized blocks design in a 2 × 4 factorial scheme composed of two levels of ractopamine, 0 and 20 ppm, combined with net energy levels of 2,300; 2,424; 2,548 and 2,668 kcal/kg of feed, with five replications, considering each animal per experimental unit. The experimental period lasted 28 days. Air temperature, relative humidity, black globe temperature, and black globe temperature and humidity index were 21.5 ± 2.8oC, 91.7 ± 6.8%, 21.7 ± 2.9oC and 70.1 ± 3.7, respectively. There was interaction between net energy levels and ractopamine, once the inclusion of 20 ppm of ractopamine in diets with 2,668 kcal of net energy/kg of feed resulted in a decrease in backfat thickness and consequently an increase in lean meat percentage and in carcass allowance index. The inclusion of 20 ppm of ractopamine caused an increased in daily weight gain, improved feed gain ratio, providing higher hot carcass weight and increasing the lean meat amount in carcasses. Diets supplemented with 20 ppm of ractopamine improve the performance and increase meat production of finishing gilts. Ractopamine is ineffective in reducing fat deposition and increasing the percentage of lean meat in the carcass of gilts fed with diets containing low concentration of energy. The level of 2,300 kcal of net energy/kg diet meets the nutritional requirement of finishing gilts under thermal comfort.