10.5680/MCPB007
Danesh Mesgaran, Sadjad
Sadjad
Danesh Mesgaran
Kuhla, Björn
Björn
Kuhla
Baumont, René
René
Baumont
Cantalapiedra-Hijar, Gonzalo
Gonzalo
Cantalapiedra-Hijar
Noziére, Pierre
Pierre
Noziére
Lund, Peter
Peter
Lund
Humphries, David
David
Humphries
Dijkstra, Jan
Jan
Dijkstra
Nutrient digestibility and balance studies
PUBLISSO
2020
ScholarlyArticle
636 Animal Husbandry
Ruminants, Bovine, Cattle
2020-12-21
en
Creative Commons Attribution 4.0 International
The nutritional value of a feed for cattle depends on its nutrient and energy contents, the extent of rumen fermentation and degradation, and the post-ruminal digestibility. Efficiency of digestion depends on different factors, for example, the apparent digestibility (estimated by subtracting the nutrients contained in faeces from the nutrients contained in dietary intake – unlike true digestibility where the endogenous and microbial amount is taken into account and corrected in final outcome) usually decreases when the level of intake increases. This decrease is due to a more rapid passage of feed through the rumen-intestinal tract, which reduces the retention time and thus the time for fermentation, digestion and absorption. Additionally, various processing techniques, which alter the physical form of feed e.g., drying, grinding, freezing, heating, or pelleting, can change the fermentation and digestibility characteristics. Chemical processing techniques, such as treatment with NaOH and/or NH3, and biological additives, such as bacterial additives or enzymatic compounds, can also alter nutrient digestibility in cattle. Different methods at the in vivo, in vitro or in situ level are available to measure the digestibility of nutrients. The total collection method in vivo, also known as a conventional digestion trial, is the most accurate method, but is time-consuming and costly to carry out. However, there are in vitro and in situ methods, which are inexpensive and can produce outcomes correlated to in vivo results. Digestion with microorganisms and/or gas production techniques are among the common in vitro methods introduced in the 1960s and 1970s. Some researchers have concluded that the in situ nylon bag method ensures a more standardised and repeatable alternative to the in vitro techniques, but it requires the use of fistulated animals. Both microbial digestion and nylon bag techniques are based on the disappearance of the substrate i.e., can be measured gravimetrically, whereas the gas production method focuses on the appearance of fermentation end products.
Chapter of the Living Handbook Methods in cattle physiology and behaviour – Recommendations from the SmartCow consortium
Horizon 2020
https://doi.org/10.13039/501100007601