| Article ID: | iaor20002126 |
| Country: | United Kingdom |
| Volume: | 61 |
| Issue: | 1 |
| Start Page Number: | 17 |
| End Page Number: | 31 |
| Publication Date: | Jul 1999 |
| Journal: | Agricultural Systems |
| Authors: | Huirne R.B.M., Dijkhuizen A.A., Kristensen A.R., Mourits M.C.M., Galligan D.T. |
| Keywords: | programming: dynamic |
A farmer exercises control over the heifer rearing unit in two main areas: a nutritional plane of growth and the moment of insemination. The two management controls interact with biological aspects of growth thereby influencing future profitability of the dairy heifer. A dynamic programming model was developed to optimize these decisions for individual heifers, using the hierarchic Markov process (HMP) technique. HMP provides a method to model a wide variety of heifer calves, differing in age, season, body weight, reproductive status and prepubertal growth level. Under Dutch conditions the optimal rearing strategy resulted in an average calving age of 22.6 months at a calving weight of 564 kg. Faced with the scarcity of exact information on the interrelationships of rearing strategies with the productivity of the dairy replacement, the strength of this heifer model lies in the field of the sensitivity analyses by providing valuable information regarding the critical components of heifer rearing.