The role of starch in early rumen development in calves
Palatability, protein levels and the inclusion of a coccidiostat are factors considered when choosing a calf feed, though the starch content is often overlooked. Starch plays an essential role in early rumen development, and subsequently, the ability of the young ruminant to effectively utilise high-fibre feeds like pasture.
Development of the rumen microbial population starts at birth, with exposure of the calf to bacteria in the environment, on the udder and in colostrum. This bacterial population changes rapidly over the next few weeks of the calf’s life, but importantly, once the calf begins to consume hard feed, bacterial fermentation of ingested feed produces large quantities of volatile fatty acids (VFAs). The VFAs, butyrate and propionate produced from the fermentation of starch, have been shown to positively impact the development of the finger-like papillae that line the inside of the rumen as shown in Figure One.
The development of a healthy rumen, with a high density of papillae, increases the surface area available for the absorption of VFAs. This helps the calf to maximise these valuable energy sources. A healthy rumen, packed with papillae, also helps maintain a healthy rumen pH.
Researchers² reviewed the effect of nutrient intake on the digestibility of calf feed. They concluded that the cumulative intake of non-fibre carbohydrates (NFC), which includes starch, sugars, and some other simple carbohydrates, appears to be critical in the development of digestibility of both the NFC and the complex structural fibre fractions of a feed. Research² estimated that until calves have consumed at least 15 kg of NFC, rumen development is not sufficient to allow for optimal extraction of nutrients.
A quick and simple way to assess the NFC content of a calf feed is to look at the starch content, as starch forms a large proportion of the NFC. High starch feeds contain a high level of NFC, while low starch feeds contain low levels. A quick look at the ingredients in the feed provides an indication of the NFC content of the feed. Feeds high in grains, such as Gusto calf feeds, have high starch levels and high levels of NFC. In contrast, feeds containing ingredients like palm kernel, soya hulls and DDGS, have low starch levels and are low in NFC.
To view Gusto Calf Meal in the latest Stock n' Save, go online to store.pggwrightson.co.nz.
1 J.D. Quigley. (1997). Development of the Rumen Epithelium. Retrieved from https://calfnotes.com/pdffiles/CN020.pdf.
2 Quigley, J.D., Hu, W., Knapp, J.R., Dennis, T.S., Suarez-Mena, F.X., & Hill, T.M. (2019). Estimates of calf starter energy affected by consumption of nutrients. 2. Effect of changing digestion on energy content in calf starters. Journal of Dairy Science, 102, 3, 2242-2253.
