Ration advisors can rely on a large variety of models to put together animal rations for different animal types and life cycles. The available models (CNCPS, NRC, Feed into Milk, INRA, …) show high variations in their complexity, biology and cost. Understanding the nutritional concepts that form the basis for the different models is one of the main challenges of ration advisors. When done correctly it allows them to meet their customers' need with the best possible ration.

In this mini-series we aim to give an overview of the characteristics of the models that are available in BESTMIX Ration calculation as a Service.

The NRC model family

The National Research Council (NRC), published by National Academic Press (USA), has been producing a varied collection of nutritional model books. In the Nutrient Requirement publications different subcommittees of animal nutrition have attempted to transform the latest nutritional information into publications that can be applied within the feed industry. These works are updated regularly for each animal type and typically contain background articles, model equations, requirement tables, feedbank information and, usually, some kind of a freeware application of the model. Despite the freeware application, there is also a need to be able to use these models and feedbanks in market standard formulation tools like BESTMIX.  

The NRC model is an industry standard used in animal rations and as such several versions are available in BESTMIX. The model works very well in helping the user to set up rations based on the animal type, phase and genetics. With a complete modeling of the animals and impressive predictions and evaluations of nutrients and parameters it is the ideal model to easily help ration advisors to create rations for calves, swine, dairy and beef cattle. 

To help our customers we offer the following models in our software:

• Dairy: NRC2001
• Beef: NRC1984, NRC2001 and NRC2016 - coming soon
• Swine: NRC2012

1 NRC - requirements and performance predictions for ruminants

1.1 Beef

1.1.1 NRC1984

NRC1984 is still one of the most accepted standards today in feedlots or cow/calf herds. It is particularly well received because of its ease of use. It offers a simple and easy to use setup, with limited inputs (body weight, frame size, gender) to be able to optimize rations and evaluate complete feeding programs. BESTMIX Feed formulation as a Service offers the possiblity to make performance adjustments on the fly to adjust the 84 model to todays genetics and standards.

1.1.2 NRC2000

Sixteen years later the NRC committee launched an updated version for beef. An interesting feature of the NRC2000 beef model, is the capability to use two levels:

• Level 1: using tabular and static ingredient supply values, moving away from a static CP as the main protein parameter to a semi-static MP (Metabolizable Protein) value
• Level 2: offers the dynamic supply value we see in CNCPS type models as well: dynamic supply and rumen flow on energy, MP and amino acids

This makes simple least-cost formulation possible, but still allows users to have the dynamic evaluation on top of that.

Just like the NRC1984 model, it is easy to deploy in cow/calf herds and feedlot situations. But it offers some more parameters to account for breed and environmental parameters.

Remark: The original publication was introduced in 1996, but extended in 2000 to make it complete. In some cases this can get confusing. When someone talks about 1996 or 2000, we are actually talking about the same model. Adifo refers to this model with NRC2000

1.1.3 NRC2016

The newest addition to the NRC publications, Nutrient Requirements for beef – Eighth Revised Edition 2016, will soon be available in BESTMIX Feed formulation as a Service. New insights and requirements from the market have driven the committee to make a model that's complete but still usable and representative for todays' situation. NRC2016 also allows 2 levels for supply: an empirical and mechanistic approach.

1.2 Dairy

1.2.1 NRC2001

In BESTMIX Feed formulation as a Service, we offer the NRC2001 dairy model. This was the update of the previous publication of NRC1989. It is also the most recent addition in the series for Dairy Cattle. NRC2001 is a dynamic model just like NRC2000 level 2 or CNCPS, but – although published shortly after the seventh revised edition for beef – it shows a very own supply side evaluation. Rumen degradation and passage rate, protein fractions a degradation, energy and amino acid submodels are available to offer a complete requirement and evaluation side.

NRC 2001 has always been recognized for its work on the amino acid model and is very well accepted as an industry standard for MP Lysine and MP Methionine supply values. The publication came without requirements for these amino acids, but thanks to the work of Dr. Chuck Schwab and others, scientific publications are available to provide target values for these amino acids in the NRC model.

It is a dynamic model and the Amino Acid model is very specific, so hard to use in a linear optimizer. Luckily, within BESTMIX Feed formulation as a Service, we have developed an algorithm to be able to optimize with MP, NEl, RDP, RUP, MP Lysine and MP Methionine.

2 NRC requirements and performance predictions for swine

2.1 NRC2012

When it comes to swine, BESTMIX offers the NRC2012 model, one of the latest nutrient requirement publications. Least-cost formulation is easy to do and predicts the performance, economics and growth for all swine animal types (growers/finishers, starting pig or nursery, gestating and lactating sows).

All NRC models offer predictions on requirements and performance on metabolizable protein and energy, minerals and vitamins. NRC2012 is compatible with net energy as well as metabolizable energy systems. Furthermore the protein, amino acid (standardized (SID) and apparent (AID) are available) and energy has a dynamic supply side. This makes for better performance predictions that are used by BESTMIX Ration calculation as a Service to optimize the ration.

NRC advantages

1. NRC offers solutions for a wide range of animal types.
2. Updated regularly.
3. NRC committees are experienced professionals from both the industry as well as the academic world.
4. One of the main advantages of the NRC models are that they're easy to learn and use. Being less complex compared with other models allows users to discover more about the many possibilities without holding back in fear of making a mistake.
5. When it comes to beef cattle the NRC2000 beef model has a lot of similarities with CNCPS 6.5.5, this allows simple least-cost formulation whilst still allowing dynamic evaluation.
6. Nutritionists and ration advisors are constantly struggling to have all possible feedstuffs and products available in the model. The NRC models offer a solution by including an ingredient database in every publication. Although the amount of ingredients is typically smaller than CNCPS's feedbank there is still a sufficient number of ingredients and commercial products available.

NRC and BESTMIX Feed formulation / Ration calculation as a Service 

Even though NRC is a lot less complex than other models it clearly offers a lot of advantages to ration advisors. Especially the many different animal species and their life cycles offer a lot of opportunities to ration advisors. To fulfill our vision of a single "one-stop-shop" ration solution we are constantly developing and integrating other models into BESTMIX Ration calculation as a service. If you are interested in having a total solution for all your feed formulation and ration calculation needs be sure to request the BESTMIX Formulation as a Service in-depth product videos.