Desempenho de bovinos Nelore e ½ Angus/Nelore adaptados em confinamento por 9 ou 14 dias
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Data
2016-03-03
Autores
Watanabe, Daniel Hideki Mariano [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O objetivo deste estudo foi avaliar os efeitos da duração do período de adaptação à dieta de alto teor de concentrado sobre o desempenho, comportamento ingestivo, características de carcaça, saúde do rúmen e digestibilidade do amido, FDN e MS em bovinos Nelore e ½ Angus/Nelore terminados em confinamento. Setenta e dois bovinos machos (com 313,5 kg ± 24,5 em média), não castrados, 36 da raça Nelore e 36 ½ Angus/Nelore, provenientes de sistema de recria em pasto, foram aleatorizados e mantidos em 24 baias (3 animais por baia) de chão batido (24 m² e 2,0 m de cocho por animal), de acordo com os tratamentos: bovinos Nelore adaptados por 9 dias, bovinos Nelore adaptados por 14 dias, bovinos ½ Angus/Nelore adaptados por 9 dias, e bovinos ½ Angus/Nelore adaptados por 14 dias, constituindo-se assim delineamento experimental em blocos casualizados em arranjo fatorial 2 × 2 (2 grupos genéticos e 2 durações do período de adaptação) com medidas repetidas no tempo, as quais foram tomadas de acordo com a variável analisada. Cada tratamento foi composto por 6 baias, as quais foram consideradas as unidades experimentais neste estudo. Após 9 ou 14 dias de adaptação, os animais receberam a ração final com 86% de concentrado. No início do período experimental e a cada 28 dias todos os animais foram pesados. A IMS foi medida todos os dias, para então calcular-se ganho de peso diário e conversão alimentar. Da mesma forma, os animais foram submetidos a avaliações de ultrassonografia no início e no final do período de confinamento para avaliação da deposição de músculos e gordura na carcaça, sendo abatidos em frigorífico comercial após 89 dias de alimentação, alcançando peso vivo final médio de 446,2 kg. Amostras de epitélio ruminal e ração, sobra e fezes foram coletadas para avaliações de saúde ruminal e digestibilidade dos nutrientes, respectivamente. Animais ½ Angus/Nelore apresentaram melhor (P<0,05) desempenho produtivo, eficiência alimentar e características de carcaça que os da raça Nelore. Foi observado (P<0,05) interação para escore de rumenites, onde animais Nelore adaptados por 14 dias apresentaram o maior escore. Bovinos adaptados em 14 dias apresentaram (P<0,05) seleção contra às partículas maiores que 19,0 mm e seleção a favor das partículas menores que 1,18 mm. Animais adaptados por 9 dias apresentaram flutuação da IMS maior (P<0,05) que os adaptados em 14 dias durante o período de adaptação. Conclui-se que o tempo de adaptação mais seguro para adaptar ambos genótipos foi de 14 dias e que o genótipo de melhor desempenho para confinamento foi o ½ Angus/Nelore.
The objective of this study was to evaluate the length of adaptation period to high concentrate diets on performance, feeding behavior, carcass traits, rumen health and starch, NDF and DM digestibility of Nellore and ½ Angus/Nellore cattle finished in feedlot. Seventy-two yearling bulls (313.5 kg ± 24.5 on the average), 36 Nellore and 36 ½ Angus/Nellore, backgrounded on pasture were randomly allocated and kept in 24 pens (3 animals/pen) with concrete floor (24 m² and 2,0 m bunk per animal) according to the treatments: Nellore adapted for 9 days, Nellore adapted for 14 days, ½ Angus/Nellore adapted for 9 days, and ½ Angus/Nellore adapted for 14 days, characterizing a randomized block design with a 2 x 2 factorial arrangement of treatments (2 genotypes and 2 lengths of adaptation period) with repeated measures over time according to the dependent variable measured. Each treatment was composed by 6 pens which was considered the experimental unit to this study. After 9 or 14 days of adaptation, yearling bulls received the finishing diet containing 86% concentrate. At the beginning of experimental period and every 28 days, yearling bulls were weighted. Dry matter intake was measure every day, and average daily gain and feed efficiency were calculate. Likewise, the deposition of muscle and fat were evaluate by ultrasound at the beginning and at the end of the study where the yearling bulls were slaughter in a commercial abattoir after 89 days of feed reaching average live body weight of 446.2 kg. Samples of rumen epithelium, diet, refusals and feces were collected for analysis of rumen health, and nutrients digestibility, respectively. Animals ½ Angus/Nellore presented better (P<0.05) performance, feed efficiency and carcass traits than the Nellore. Interaction (P<0.05) to rumenitis was observed, where Nellore adapted in 14 days presented the higher score. Yearling bulls adapted in 14 days presented (P<0.05) selection against particles higher than 19.0 mm and selection in favor of the particles lower than 1,18 mm. Animals adapted in 9 days showed higher DMI variation (P<0.05) than the adapted in 14 days during the adaptation period. Thus, it is possible to concludes that the most security adaptation length to both genotypes is the 14 days and the better genotype to feedlot performance is the ½ Angus/Nellore.
The objective of this study was to evaluate the length of adaptation period to high concentrate diets on performance, feeding behavior, carcass traits, rumen health and starch, NDF and DM digestibility of Nellore and ½ Angus/Nellore cattle finished in feedlot. Seventy-two yearling bulls (313.5 kg ± 24.5 on the average), 36 Nellore and 36 ½ Angus/Nellore, backgrounded on pasture were randomly allocated and kept in 24 pens (3 animals/pen) with concrete floor (24 m² and 2,0 m bunk per animal) according to the treatments: Nellore adapted for 9 days, Nellore adapted for 14 days, ½ Angus/Nellore adapted for 9 days, and ½ Angus/Nellore adapted for 14 days, characterizing a randomized block design with a 2 x 2 factorial arrangement of treatments (2 genotypes and 2 lengths of adaptation period) with repeated measures over time according to the dependent variable measured. Each treatment was composed by 6 pens which was considered the experimental unit to this study. After 9 or 14 days of adaptation, yearling bulls received the finishing diet containing 86% concentrate. At the beginning of experimental period and every 28 days, yearling bulls were weighted. Dry matter intake was measure every day, and average daily gain and feed efficiency were calculate. Likewise, the deposition of muscle and fat were evaluate by ultrasound at the beginning and at the end of the study where the yearling bulls were slaughter in a commercial abattoir after 89 days of feed reaching average live body weight of 446.2 kg. Samples of rumen epithelium, diet, refusals and feces were collected for analysis of rumen health, and nutrients digestibility, respectively. Animals ½ Angus/Nellore presented better (P<0.05) performance, feed efficiency and carcass traits than the Nellore. Interaction (P<0.05) to rumenitis was observed, where Nellore adapted in 14 days presented the higher score. Yearling bulls adapted in 14 days presented (P<0.05) selection against particles higher than 19.0 mm and selection in favor of the particles lower than 1,18 mm. Animals adapted in 9 days showed higher DMI variation (P<0.05) than the adapted in 14 days during the adaptation period. Thus, it is possible to concludes that the most security adaptation length to both genotypes is the 14 days and the better genotype to feedlot performance is the ½ Angus/Nellore.
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Palavras-chave
Acidose, Comportamento, Digestibilidade, Genótipo, Rúmen, Acidosis, Behavior, Digestibility, Genotype, Rumen