Adjusted model for Jersey
The model for Jersey dairy cows in NorFor has been adjusted in the 3, May 2023 release. Digestibility of a ration in Jersey cows is now more similar to the digestibility in Holstein dairy cows. Before, diets to Jersey cows were often limiting in protein balance in the rumen (PBV), had a surplus of metabolizable protein (amino acids absorbed in the small intestines, AAT) and low crude protein. The model has been changed so estimated feed intake capacity for Jersey cows now has increased slightly, also passage rates of nutrients through the rumen and microbial efficiency has been adjusted.
The user will notice that when optimizing rations for Jersey cows it will result in slightly higher daily dry matter intake, up to 1 kg DM more per cow, and it is easier to reach the optimisation settings, e.g. minimum of PBV of 10 g/kg DM and maximum of rumen load index (RLI) of 0.6. Most of the rations will result in PBV between 7 and 10 g/kg DM, AAT will be close to 15 g/MJ and with a crude protein concentration of 160 to 170 g per kg DM.
This adjustment will be found in the feed ration calculation (FRC) version 2.15 and one-day feeding control (OFC) version 1.43 and is available for all users of NorFor Feed Ration Optimizer (NFRO), DMS, Optifôr, IndividRAM, TypFoder and FoderOpti.