TY - JOUR
T1 - A dairy herd model for use in whole farm simulations
AU - Rotz, C. A.
AU - Mertens, D. R.
AU - Buckmaster, D. R.
AU - Allen, M. S.
AU - Harrison, J. H.
N1 - Funding Information:
The authors appreciate the assistance received in model development from L. D. Satter and R. E. Muck, U.S. Dairy Forage Research Center, Madison, Wisconsin, J. R. Black, Michigan State University, East Lansing, and C. J. Sniffen, Miner Agricultural Research Institute, Chazy, New York. The work was primarily supported by the USDA Agricultural Research Service with further support from the Michigan Agricultural Experiment Station and a grant from the USDA National Research Initiative Competitive Grants Program award number 94-37502-0970.
PY - 1999/12
Y1 - 1999/12
N2 - A dairy herd submodel was created for integration with other farm submodels to form DAFOSYM, a dairy farm simulation model. The herd submodel determines the best mix of available feeds to meet the fiber, energy, and protein requirements for each of six animal groups. The groups are early-, mid-, late-, and nonlactating cows, heifers over 1 yr old, and younger heifers. Feed intake, milk production, and manure dry matter and nutrient (N, P, and K) excretions are functions of the nutrient content of the diets. Required feed characteristics include crude protein, rumen degradable protein, acid detergent insoluble protein, net energy of lactation, neutral detergent fiber, total digestible nutrients, P, and K concentrations. Feed intake is predicted with fill and roughage units. These units are functions of feed neutral detergent fiber adjusted for particle size distribution and the relative rate of ruminal digestibility or physical effectiveness of the fiber. The herd submodel predicted feed intakes, nutrient requirements, diets, and manure excretions similar to those recommended or measured for dairy animals. When integrated with other farm components in DAFOSYM, the comprehensive model provides a useful tool for evaluating the long-term performance and economics of alternative dairy farm systems.
AB - A dairy herd submodel was created for integration with other farm submodels to form DAFOSYM, a dairy farm simulation model. The herd submodel determines the best mix of available feeds to meet the fiber, energy, and protein requirements for each of six animal groups. The groups are early-, mid-, late-, and nonlactating cows, heifers over 1 yr old, and younger heifers. Feed intake, milk production, and manure dry matter and nutrient (N, P, and K) excretions are functions of the nutrient content of the diets. Required feed characteristics include crude protein, rumen degradable protein, acid detergent insoluble protein, net energy of lactation, neutral detergent fiber, total digestible nutrients, P, and K concentrations. Feed intake is predicted with fill and roughage units. These units are functions of feed neutral detergent fiber adjusted for particle size distribution and the relative rate of ruminal digestibility or physical effectiveness of the fiber. The herd submodel predicted feed intakes, nutrient requirements, diets, and manure excretions similar to those recommended or measured for dairy animals. When integrated with other farm components in DAFOSYM, the comprehensive model provides a useful tool for evaluating the long-term performance and economics of alternative dairy farm systems.
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U2 - 10.3168/jds.S0022-0302(99)75541-4
DO - 10.3168/jds.S0022-0302(99)75541-4
M3 - Article
C2 - 10629832
AN - SCOPUS:0033256683
SN - 0022-0302
VL - 82
SP - 2826
EP - 2840
JO - Journal of dairy science
JF - Journal of dairy science
IS - 12
ER -