1026 The eighth revised edition of the Nutrient Requirements of Beef Cattle: environmental issues

Abstract The California net energy system (CNES) was the reference for the development of most energy requirement systems worldwide, such as Nutrient Requirements of Beef Cattle (NASEM, Nutrient requirements of beef cattle, 8th Revised ed, 2016) and Brazilian Nutrient Requirements of Zebu and Crossbred Cattle (Valadares Filho, S. C., L. F. C. Silva, M. P. Gionbelli, P. P. Rotta, M. I. Marcondes, M. L. Chizzotti, and L. F. Prados, BR-CORTE: nutrient requirements of zebu and crossbred cattle, 3rd ed, 2016). This review aimed to compare methods used by NASEM and BR-CORTE to estimate the energy requirements for beef cattle. The net energy requirements for maintenance (NEm) of BR-CORTE is based on empty body weight (EBW), whereas NASEM uses shrunk body weight (SBW), but the Bos taurus indicus presents 10% to 8% lower NEm than Bos taurus taurus. We have compared animals with different EBW and SBW but with same equivalent empty body weight/standard reference weight ratio (0.75), as both systems have suggested different mature weights. Both systems predicted similar net energy requirements for gain (NEg) for animals with 1.8 kg of daily gain. However, estimated empty body gain was lower for NASEM estimations when the same metabolizable energy for gain is available. For pregnancy and lactation of beef cows, the NEm and net energy requirements for pregnancy (NEp) of a Zebu cow estimated by BR-CORTE were lower than the values estimated by NASEM. Furthermore, the magnitude of differences between these systems regarding NEp increased as pregnancy days increase. The NASEM and BR-CORTE systems have presented similar values for energy requirement for lactation (0.72 and 0.75 Mcal/kg milk, respectively).

Download Full-text

Nutrient requirements of beef cattle in tropical climates

Energy and protein metabolism and nutrition ◽

10.3920/978-90-8686-891-9_7 ◽

2019 ◽

Author(s):

S.C. Valadares Filho ◽

F.A.S. Silva ◽

P.D.B. Benedeti ◽

M.F. Paulino ◽

M.L. Chizzotti

Keyword(s):

Beef Cattle ◽

Nutrient Requirements ◽

Tropical Climates

Download Full-text

AN EVALUATION OF TOTAL DIGESTIBLE NUTRIENTS, METABOLIZABLE ENERGY, AND NET ENERGY FOR THE PREDICTION OF ENERGY REQUIREMENTS FOR BEEF CATTLE IN ONTARIO

Canadian Journal of Animal Science ◽

10.4141/cjas73-073 ◽

1973 ◽

Vol 53 (3) ◽

pp. 471-477

Author(s):

D. I. DICKIE ◽

J. W. WILTON ◽

T. D. BURGESS

Keyword(s):

Beef Cattle ◽

Research Council ◽

National Research Council ◽

Domestic Animals ◽

Metabolizable Energy ◽

Energy Requirements ◽

Net Energy ◽

Nutrient Requirements ◽

National Academy Of Sciences ◽

Academy Of Sciences

Four studies and populations of beef animals were used to evaluate different methods of expressing energy requirements by comparing actual to predicted gains of bulls and steers fed in Ontario. Large differences between predicted and actual gains occurred. Based on a total of 503 animals, gains predicted by the net energy method (National Academy of Sciences–National Research Council. 1970. Nutrient requirements of domestic animals. 4. Nutrient requirements of beef cattle. (4th rev.). Nat. Acad. Sci., Publ. ISBN 0-309-01754-8; Washington, D.C.) were approximately 20% below the actual gains but exceptions within treatment groups were evident. Three hundred and twenty-five individually fed bulls were used to compare the accuracy with which gains were predicted from equations using total digestible nutrients (National Academy of Sciences–National Research Council. 1963. Nutrient requirements of domestic animals. 4. Nutrient requirements of beef cattle. Nat. Acad. Sci., Publ. 1137, Washington, D.C.) net energy (National Academy of Sciences–National Research Council. 1970. Nutrient requirements of domestic animals. 4. Nutrient requirements of beef cattle. (4th rev.). Nat. Acad. Sci., Publ. ISBN 0-309-01754-8, Washington, D.C), and metabolizable energy (Agricultural Research Council. 1965. The nutrient requirements of farm animals. No. 2. Ruminants. London, England). The metabolizable energy method predicted gains most accurately.

Download Full-text

1023 The eighth revised edition of the Nutrient Requirements of Beef Cattle: reproduction

Journal of Animal Science ◽

10.2527/jam2016-1023 ◽

2016 ◽

Vol 94 (suppl_5) ◽

pp. 490-490 ◽

Cited By ~ 1

Author(s):

R. P. Lemenager ◽

J. S. Caton ◽

M. L. Galyean ◽

L. O. Tedeschi

Keyword(s):

Beef Cattle ◽

Nutrient Requirements ◽

Cattle Reproduction

Download Full-text

Structure of a dynamic simulation model for beef cattle production systems

Canadian Journal of Animal Science ◽

10.4141/a99-020 ◽

1999 ◽

Vol 79 (4) ◽

pp. 409-417 ◽

Cited By ~ 20

Author(s):

H. Pang ◽

M. Makarechian ◽

J. A. Basarab ◽

R. T. Berg

Keyword(s):

Beef Cattle ◽

Production Systems ◽

System Optimization ◽

Sensitivity Analyses ◽

Nutrient Requirements ◽

Beef Production ◽

Cattle Production ◽

Forage Production ◽

Data Set ◽

Beef Cattle Production

A dynamic deterministic model for simulating beef cattle production systems is developed to evaluate the effects of production traits and management strategies on the bioeconomic efficiency of beef production systems. The model, named Alberta Beef Production Simulation System (ABPSS), is composed of four major submodels: herd inventory, nutrient requirement, forage production, and economic submodels. The herd inventory submodel is used to simulate population dynamics and feed requirements in the herd. The nutrient requirements submodel is mainly based on the 1996 version of the National Research Council (NRC). It is used to evaluate nutrients and feed requirements for calves and cows depending on their physiological status (maintenance, growth, lactation and gestation) and the climatic condition. The forage production sub-model is used to predict forage growth rate, cattle grazing rate, available forage biomass and total hectares required for grazing. The economic submodel measures bioeconomic efficiency, as net return per cow, by subtracting total cost from total return. The nutrient requirements predicted by ABPSS were compared with those recommended by the NRC for testing. The results that were predicted by the NRC model and ABPSS model were similar, as expected. Sensitivity analyses showed that cow mature weight, milk production, calf weaning weight and feed prices were the most critical input parameters in the model. It must be noted that the model was developed based on available experimental results and data from the literature and, due to the unavailability of a suitable data set, the model could not be validated. We suggest that the ABPSS has the potential for providing a useful method for simultaneous consideration of many factors in an integrated system, which could be helpful to beef cattle extension specialists and cow-calf production managers for assessing the potential effects of different management and selection strategies on bioeconomic efficiency. Key words: Beef cattle, simulation and modelling, production system, optimization

Download Full-text