Duration of ractopamine supplementation in diets for finishing gilts maintained under high temperature environment/Duracao da suplementacao de ractopamina em dietas para leitoas em terminacao mantidas sob alta temperatura ambiente

• Published in: Ciência rural 2011-02, Vol.41 (2), p.337
• Main Authors: da Silva, Elizangela Alves, Kiefer, Charles, de Moura, Mariana Souza, Bunzen, Silvano, dos Santos, Alexandre Pereira, Silva, Camilla Mendonca, Nantes, Clariana Leon
• Format: Article
• Language: Spanish
• Subjects: Legal fees
• ISSN: 0103-8478

The study was conducted to evaluate the duration of the supplementation of ractopamine in the diet of finishing gilts maintained under high temperature environment. Forty eight females, with initial weight of 70.4 [+ or -] 2.6kg were used. The pigs were distributed in randomized blocks design of six treatments (supplementation of ractopamine for 0, 7, 14, 21, 28 and 35 days pre-slaughter) and four replications, each experimental unit consisted of two animals. The final weight and daily feed intake were not affected (P>0.05) by treatments. The weight gain increased and the feed conversion decreased linearly (P0.05) by duration of supplementation of ractopamine in the diet. The weights of the lungs, heart, liver, kidneys and spleen were not modified (P>0. 05) by treatments. It was concluded that inclusion of 20ppm of ractopamine in the diet of finishing gilts maintained under high temperature environment during 28 days maximizes the response of daily gain and during 35 days maximizes the response to feed conversion. However, the inclusion of the additive does not alter the quantitative characteristics of carcass and does not affect the development of the viscera. Key words: additives, carcass characteristics, distribution of energy, performance. Este estudo foi realizado com o objetivo de avaliar a duracao da suplementacao de ractopamina na dieta de leitoas em terminacao, mantidas sob alta temperatura ambiente. Foram utilizadas 48 leitoas com peso inicial de 70,4 [+ or -] 2,6kg, distribuidas no delineamento de blocos ao acaso, com seis tratamentos (suplementacao de ractopamina por 0, 7, 14, 21, 28 e 35 dias pre-abate) e quatro repeticoes, sendo a unidade experimental constituida por dois animais. O peso final e o consumo de racao diario nao foram influenciados (P>0,05) pelos tratamentos. O ganho de peso aumentou e a conversao alimentar reduziu linearmente (P0,05) pela duracao da suplementacao de ractopamina na dieta. O peso