Physically effective fiber changes nutrient levels of total mixed ration and fecal parameters in beef feedlots

• Published in: Ciência rural Vol. 51; no. 5
• Main Authors: Cunha, Gabriel Santos Persiquini, Maia, Moises de Aguiar, Fernandes, Luís Miguel Gonçalves, Geraseev, Luciana Castro, Chaves, Amália Saturnino
• Format: Journal Article
• Language: English; Portuguese
• Published: Santa Maria Universidade Federal de Santa Maria Centro de Ciencias Rurais 01.01.2021; Universidade Federal de Santa Maria
• Subjects: AGRONOMY; Animals; Beef; Carbohydrates; Cattle; Corn; Dry matter; Evaluation; Factory farming; Farms; Feces; Feedlots; Feeds; fiber effectiveness; Intensive farming; Mathematical models; Nutrient content; Parameters; Particle size; Particle size distribution; pH effects; Proteins; Separators; Size distribution; Sorghum; Starch; Total mixed rations; amido; starch; fiber effectiveness; tamanho de partícula; particle size distribution; fibra efetiva
• ISSN: 0103-8478; 1678-4596; 1678-4596
• DOI: 10.1590/0103-8478cr20200663

This study evaluated the effects of the physically effective fiber (peNDF) content on nutrient composition of the total mixed ration (TMR), orts and fecal parameters in 15 commercial beef feedlots. The particle size distribution of TMR was measured adopting Penn State Particle Size Separator (PSPS). Samples were evaluated for dry matter (DM), ash, ether extract (EE), crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and starch content. Fecal samples were also evaluated for pH and score. The feedlots were categorized into peNDF<20% and peNDF ≥ 20%. Data were analyzed by a model that included fixed effects of treatment and covariates (sex and genetic groups). Levels of DM, CP, EE and starch were lower in TMR with peNDF ≥ 20% (P<0.05). Fecal dry matter was higher and morning fecal pH was lower for TMR with peNDF<20% (P<0.05). Physically effective fiber changed nutrient levels in TMR, orts, fecal pH and DM. So, using PSPS and fecal parameters are practical and indirect tools for measuring fecal starch and assessing the effectiveness of the diet supplied to ruminants. RESUMO: O objetivo desse estudo foi avaliar o teor de fibra fisicamente efetiva (FDNfe) de dietas totais e seus efeitos nos nutrientes da dieta, das sobras e nos parâmetros fecais de bovinos de corte em 15 confinamentos comerciais. As amostras da dieta foram separadas utilizando a peneira Penn State Particle Size Separator (PSPS). As amostras foram analisadas quanto aos teores de matéria seca (MS), matéria mineral (MM), extrato etéreo (EE), proteína bruta (PB), fibra em detergente neutro (FDN), fibra em detergente ácido (FDA) e amido. Nas amostras de fezes também foram avaliadas o escore e pH fecal. Os confinamentos foram categorizados em dois tratamentos: FDNfe<20% e FDNfe≥20%. Os dados foram analisados por um modelo que incluiu os efeitos de grupo e covariável (sexo e grupo genético). Os teores de MS, PB, EE e amido foram menores nas dietas com FDNfe≥20%(P<0,05). A MS fecal foi maior e pH fecal matinal foi menor nas dietas com FDNfe<20% (P<0,05). Sendo assim a efetividade da fibra alterou os nutrientes da dieta total e sobras, bem como as variáveis pH e MS fecal. Com isso, o uso de PSPS e parâmetros fecais são ferramentas práticas e indiretas para medir o amido fecal e a efetividade da dieta em confinamentos de bovinos comerciais.