Comparisons between intake values observed and predicted by nutritional systems for confined nellore cattle

Aline Maria Soares Ferreira,Carina Carina Ubirajara De Faria,Egleu Diomedes Marinho Mendes,Ester Ferreira Felipe,Simone Pedro Da Silva

doi:10.14393/bj-v37n0a2021-54149

Aline Maria Soares Ferreira, Carina Carina Ubirajara De Faria + Show 3 more

Open Access

https://doi.org/10.14393/bj-v37n0a2021-54149

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Abstract

This study compared the dry matter intake (DMI) of Nellore heifers and bulls in the feedlot, predicted by the BR-Corte (2010 and 2016) and NRC (2000) nutritional systems. Hence, two experiments were conducted in a completely randomized design. The first one used 47 Nellore bulls, not castrated, with an average initial weight of 413 kg, and 19 months of age. The second experiment used 24 Nellore heifers with an average initial weight of 300 kg and 23 months of age. The accuracy and approximation of the DMI estimates by the nutritional systems were adjusted with the simple linear regression model and the root mean square error of prediction (RMSEP). The DMI was 8.06 kg day-1 for Nellore heifers and 11.54 kg day-1 for bulls, which are higher than the values predicted by the nutritional systems. The NRC (2000) and BR-Corte (2010 and 2016) underestimated DMI in 20.84, 20.09, and 19.35% for heifers and 28.07, 16.20, and 11.78% for bulls, respectively. It was concluded that the BR-Corte 2010 and 2016 were the most suitable models to estimate the DMI of Nellore heifers and bulls for higher precision and accuracy.

Highlights

Dry matter intake (DMI) is the most important variable that affects animal performance
The accuracy and approximation of the dry matter intake (DMI) estimates by the nutritional systems were adjusted with the simple linear regression model and the root mean square error of prediction (RMSEP)
The DMI was 8.06 kg day-1 for Nellore heifers and 11.54 kg day-1 for bulls, which are higher than the values predicted by the nutritional systems

Summary

Introduction

Dry matter intake (DMI) is the most important variable that affects animal performance. According to Mertens (1994), 60 to 90% of variations in animal performance are explained by consumption and only 10 to 40% by the effects attributed to the nutritional value characteristics of feed, such as digestibility This means that maximizing animal performance requires understanding the feed intake of animals, which is an extremely difficult variable to obtain using mathematical models because it is affected by numerous factors related to animal diet, environment, and management, among others. Nutritional systems such as the National Research Council (NRC), Agricultural and Food Research Council (AFRC), Cornell Net Carbohydrate and Protein System (CNCPS), and BR-Corte have produced empirical models to estimate intake. The predominant genetic group in Brazil is Zebu, with a high number of Nellore animals, and the BR-Corte system developed models to estimate consumption in Zebu and crossbred animals

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