Effects of restricted vs. step up dietary adaptation for 6 or 9 days on feedlot performance, feeding behaviour, ruminal and blood variables of Nellore cattle

Abstract

SummaryThis study was designed to determine effects of quantitatively restricted intake of the final finishing diet as a means of dietary adaptation compared with diets increasing in concentrate (step up) over periods of 6 and 9 days on feedlot performance, carcass characteristics, feeding behaviour, blood gas profile and rumen morphometrics of Nellore cattle. One hundred twenty 22-month-old Nellore bulls (352 ± 20 kg) were randomly allocated in 24 pens and fed for 84 days. The experimental design was a completely randomized block with 2 × 2 factorial arrangement of treatments: adaptation using either step up protocol for 6 days or 9 days or restriction protocol for 6 days or 9 days, where the pen (five bullocks/pen; six pens/treatment) was considered the experimental unit. Cattle adapted by step up protocol had significantly greater average daily gain throughout the study when compared to those adapted by restriction protocol, regardless of adaptation length. During the adaptation period, a greater dry matter intake fluctuation was observed for animals maintained on restriction programme when compared to those adapted to the finishing diets using step up protocol. In addition, a protocol × length interaction for rumenitis scores was observed, where the level of injuries to the ruminal wall was significantly higher for the cattle adapted by restriction protocol for 9 days and lower for animals submitted for 9 days to the step up programme. Likewise, a protocol × length interaction for mitotic index was observed, in which cattle adapted by step up protocol for 9 days had lower numbers of cells in mitosis. Thus, the step up protocol led to better feedlot performance, and based on this fact, the length of 9 days promoted better rumen epithelium adaptation of Nellore cattle to high-concentrate diets. K E Y W O R D Sconcentrate, intake, papillae, protocol, rumen

Ruminal Fermentation Pattern, Bacterial Community Composition, and Nutrient Digestibility of Nellore Cattle Submitted to Either Nutritional Restriction or Intake of Concentrate Feedstuffs Prior to Adaptation Period

“…In general, the average adaptation period in Brazilian feedlots is reported to be 16.2 days ( Pinto and Millen, 2018 ). Further work evaluating different adaptation periods ( Perdigão et al, 2017 ; Barducci et al, 2019 ; Parra et al, 2019 ) suggested that Nellore cattle should spend a minimum of 14 days adapting to a high-concentrate diet in a step-up manner, where increasing amounts of concentrate are successively added to the adaptation diet. However, the application of these guidelines is confounded by the dietary history of the incoming calves, which can differ significantly by sourcing location.…”

The Potential of Shortening the Adaptation of Nellore Cattle to High-Concentrate Diets Using Only Virginiamycin as Sole Feed Additive

“…During finishing, the cattle fed VM6 also had more meals per day and less DMI intake per meal in relation to the cattle fed VM14. Previous studies have reported that 6 days of adaptation resulted in no improvement in feedlot performance and negative effects on rumen epithelium development ( 1 , 4 ). As a result, despite the lack of VM effect on the HCW and ADG, the carcass fat deposition of the cattle fed VM6 was also negatively impacted by shortening the adaptation period.…”

“…Adaptation studies have been conducted previously in Brazil to determine the most appropriate adaptation length to highconcentrate diets for Nellore cattle (1)(2)(3)(4)(5). Based on the results of these studies, Nellore cattle should not be adapted in less than 14 days, regardless of the type of adaptation protocol adopted, corn processing method, and nutritional background.…”

Probióticos Fúngicos Na Dieta De Alto Grão Para Ruminantes

“…ISSN 2525-8761 dias, segundo recomendação de vários estudos (BROWN;PONCE;PULIKANTI, 2006;PERDIGÃO et al, 2018;BARDUCCI et al, 2019). A adaptação pode ser do tipo escada ou por restrição (PERDIGÃO et al, 2018;BARDUCCI et al, 2019 De 2005 até os dias atuais diversos trabalhos têm comprovado o aumento da eficiência, a melhoria na conversão alimentar e no acabamento da carcaça, assim como, a redução no custo de produção de ruminantes submetidos a dietas de alto grão (MANDARINO et al, 2013;OLIVEIRA et al, 2015a;FRUET et al, 2016;PARENTE et al, 2016). Esses resultados têm servido como fatores instigadores para o aumento de confinamentos de bovinos de corte em dieta de alto grão no Brasil (MANDARINO et al, 2013;PAULINO et al, 2013;VALADARES FILHO et al, 2016).…”

“…).De acordo comPerdigão et al (2018) eBarducci et al (2019) o protocolo de adaptação tipo escada consiste no fornecimento à vontade da dieta mista com aumento gradual dos ingredientes concentrados de acordo com o tempo de adaptação, que pode ser de 9 a 14 dias, até que se atinja o nível desejável de concentrado para a dieta de acabamento, que normalmente é composta com 85% de grão energético e 15% núcleo.O protocolo de adaptação tipo restrição tem como fundamento a restrição da quantidade ingerida da dieta final com aumento gradual até atingir o fornecimento ad libitum, sendo recomendado iniciar a restrição com fornecimento de 1,76% do peso corporal (PC)(BARDUCCI et al., 2019).Barducci et al (2019) avaliando os dois protocolos de adaptação, escada versus restrição, com dois períodos de adaptação, 9 e 14 dias, reforçaram a recomendaçãode Brown;Ponce;Pulikanti (2006), de utilizar, no mínimo, 14 dias de adaptação, e consideraram o protocolo escada como sendo o mais indicado, o que corrobora comPerdigão et al (2018) que verificaram melhor adaptação dos animais à dieta de alto grão utilizando o protocolo escada.…”