The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
The Revista Brasileira de Zootecnia (RBZ) is a publication dedicated to the broad field of Animal Science. We publish high-quality, original scientific research that spans across diverse areas within the discipline. The scope of RBZ encompasses a wide range of topics, including aquaculture, biometeorology and animal welfare, forage crops and grasslands, animal and forage plants breeding and genetics, animal reproduction, ruminant and non-ruminant nutrition, meat science and muscle biology, precision livestock, and animal production systems and agribusiness.
This research was developed to estimate the energy values (TDN) of feeds, concentrate and roughage, through equations proposed by NRC (2001) and validate from the comparison among TDN values estimated by these equations and those observed in the total collection feces. Five concentrate feeds (wheat bran, soybean meal, corn ground, whole soybean and whole cotton seed) an five roughage feeds (brachiaria hay, corn silage, tifton haylage, elephant grass silage and elephantgrass) were evaluated by using 20 crossbred Holstein x Zebu steers. The procedure to validate the variables evaluated was done by adjusting models of simple linear regression using predicted and observed values. The observed and predicted value of TDN values for roughage and concentrate feeds were similar (P>0,05). It was concluded that the equations proposed by NRC (2001) were efficient to estimate the TDN values of feeds under brazilian conditions.
Validation of NRC (2001) equations for estimation of energy value of feeds in Brazilian conditions
Costa,Marcos Antonio Lana and Filho,Sebastião de Campos Valadares and Valadares,Rilene Ferreira Diniz and Paulino,Mário Fonseca and Cecon,Paulo Roberto and Paulino,Pedro Veiga Rodrigues and Chizzotti,Mário Luiz and Paixão,Mônica Lopes. Validation of NRC (2001) equations for estimation of energy value of feeds in Brazilian conditions. R. Bras. Zootec. [online]. 2005, vol.34, 1, [cited 2026-04-23], pp.280-287. Available from: <https://rbz.org.br/article/validation-of-nrc-2001-equations-for-estimation-of-energy-value-of-feeds-in-brazilian-conditions/>. ISSN 1516-3598. https://doi.org/10.1590/S1516-35982005000100032.
Costa,Marcos Antonio Lana; Filho,Sebastião de Campos Valadares; Valadares,Rilene Ferreira Diniz; Paulino,Mário Fonseca; Cecon,Paulo Roberto; Paulino,Pedro Veiga Rodrigues; Chizzotti,Mário Luiz; Paixão,Mônica Lopes. Validation of NRC (2001) equations for estimation of energy value of feeds in Brazilian conditions. R. Bras. Zootec., v.34, 1, p. 280-287. Feb. 2005. Available from: <https://rbz.org.br/article/validation-of-nrc-2001-equations-for-estimation-of-energy-value-of-feeds-in-brazilian-conditions/>. acess on 23 Apr. 2026. https://doi.org/10.1590/S1516-35982005000100032.
Costa,Marcos Antonio Lana, & Filho,Sebastião de Campos Valadares, & Valadares,Rilene Ferreira Diniz, & Paulino,Mário Fonseca, & Cecon,Paulo Roberto, & Paulino,Pedro Veiga Rodrigues, & Chizzotti,Mário Luiz, & Paixão,Mônica Lopes. (2005). Validation of NRC (2001) equations for estimation of energy value of feeds in Brazilian conditions. R. Bras. Zootec., 34(1) , 280-287. https://doi.org/10.1590/S1516-35982005000100032.
CostaMarcos Antonio Lana, FilhoSebastião de Campos Valadares, ValadaresRilene Ferreira Diniz, PaulinoMário Fonseca, CeconPaulo Roberto, PaulinoPedro Veiga Rodrigues, ChizzottiMário Luiz, PaixãoMônica Lopes. Validation of NRC (2001) equations for estimation of energy value of feeds in Brazilian conditions. R. Bras. Zootec. [Internet]. 2005 Feb [cited 2026 Apr 23]; 34(1): 280-287. Available from: https://rbz.org.br/article/validation-of-nrc-2001-equations-for-estimation-of-energy-value-of-feeds-in-brazilian-conditions/. https://doi.org/10.1590/S1516-35982005000100032.
Figure 6
Differential abundance for the species Faecalibacterium prausnitzii (A) and Megamonas funiformis (B).
