Feed formulation: Models and methods

Ruminant nutritionists in the private sector serve both the animal feed manufacturing industry and companies that supply products and services to feed manufacturers and livestock producers.

- By Stephen Slippers

The models and methods they use for their primary task-feed formulation - align with the specific sector in which they operate (Table 1). However, in practice, the range of available software extends beyond what is listed in Table 1, particularly when considering smaller manufacturers and service providers.

Most computer models and feed formulation software rely on but a few feed evaluation systems. These include the American National Academies of Sciences, Engineering, and Medicine (NASEM) system, the Cornell Net Carbohydrate and Protein System (CNCPS) developed by Cornell University in the United States, and the intestinal digestible protein (DVE)/CVB/ Schothorst system from the Netherlands.

In South Africa other evaluation systems, such as those from France, Scandinavia, and Germany, are occasionally used, though on a much smaller scale. The non-linear systems employed primarily simulate the digestive system and metabolic processes of ruminant species. These systems include specialised submodels for dairy and beef cattle (covering both extensive grazing and feedlot operations) as well as small stock, such as sheep and goats.

Efficient simulation models

These simulation models are uniquely designed to integrate information about animals, including bodyweight, body condition, and fat concentration, alongside productivity metrics such as milk production, milk composition, and growth rates.

The models also incorporate data on the production environment, including temperature, humidity, and feeding systems (e.g., total mixed ration [TMR] versus pasture-based systems). Other key factors integrated into the models include kraal conditions, pen and camp sizes, milking frequency per day, walking distances between pens or camps and the milking parlour, and terrain slopes.