The papillae (finger-like protrusions) that line the digestive tract need to be developed to allow maximum absorption of nutrients that have been broken down from feed. The stimulus for this is production of volatile fatty acids (VFAs), in particular propionic and butyric acid. These are produced when starch containing materials, like, maize and barley, are fermented in the rumen.
The breakdown of fibrous material does little to simulate papillae growth but is involved in improving the musculature of the rumen. It is physical fibre that does this, like hay and straw.
A high level of neutral detergent fibre (NDF) in calf pellets does not improve muscle tone. It can also mean less of the essential materials like grain and protein meals are included. Calves eat a very small quantity of meal in the first few weeks. It is imperative that this feed is nutrient dense, containing the best quality ingredients available.
Look at comparing price per unit of protein or per unit of ME to get a good view of what you are buying. On a dollars per tonne basis, a feed might look very appealing but it is imperative to consider why this might be. Cheap, filler raw materials are by-products and can be more likely to add to a mycotoxin risk. Young calves without a developed rumen struggle to deal with mycotoxins and can suffer from reduced feed intake, scours and a suppressed immune system.
Feed additives in calf meal play an important role. This may be a coccidiostat, Rumensin or Bovatec. These additives reduce the level of coccidia that can affect the calf but do not totally eliminate them. This allows the animal to recognise the challenge and as they get older, be able to fight it themselves. Other additives can be included such as prebiotics and probiotics. Prebiotics are a “food” source for good bacteria in the gut. Probiotics are good bacteria themselves. Using a calf feed containing a food source for good bacteria encourages their growth. The more good bacteria populating the gut, the less room there is for bad / pathogenic bacteria. In addition, the environment becomes less favourable for bad bacteria. More good, and less bad, bacteria leads to a reduction in disease challenge, reduced incidence of scours and more nutrients available for growth instead of fighting a disease challenge.