Know more

About cookies

What is a "cookie"?

A "cookie" is a piece of information, usually small and identified by a name, which may be sent to your browser by a website you are visiting. Your web browser will store it for a period of time, and send it back to the web server each time you log on again.

Different types of cookies are placed on the sites:

  • Cookies strictly necessary for the proper functioning of the site
  • Cookies deposited by third party sites to improve the interactivity of the site, to collect statistics

Learn more about cookies and how they work

The different types of cookies used on this site

Cookies strictly necessary for the site to function

These cookies allow the main services of the site to function optimally. You can technically block them using your browser settings but your experience on the site may be degraded.

Furthermore, you have the possibility of opposing the use of audience measurement tracers strictly necessary for the functioning and current administration of the website in the cookie management window accessible via the link located in the footer of the site.

Technical cookies

Name of the cookie


Shelf life

CAS and PHP session cookies

Login credentials, session security



Saving your cookie consent choices

12 months

Audience measurement cookies (AT Internet)

Name of the cookie


Shelf life


Trace the visitor's route in order to establish visit statistics.

13 months


Store the anonymous ID of the visitor who starts the first time he visits the site

13 months


Identify the numbers (unique identifiers of a site) seen by the visitor and store the visitor's identifiers.

13 months

About the AT Internet audience measurement tool :

AT Internet's audience measurement tool Analytics is deployed on this site in order to obtain information on visitors' navigation and to improve its use.

The French data protection authority (CNIL) has granted an exemption to AT Internet's Web Analytics cookie. This tool is thus exempt from the collection of the Internet user's consent with regard to the deposit of analytics cookies. However, you can refuse the deposit of these cookies via the cookie management panel.

Good to know:

  • The data collected are not cross-checked with other processing operations
  • The deposited cookie is only used to produce anonymous statistics
  • The cookie does not allow the user's navigation on other sites to be tracked.

Third party cookies to improve the interactivity of the site

This site relies on certain services provided by third parties which allow :

  • to offer interactive content;
  • improve usability and facilitate the sharing of content on social networks;
  • view videos and animated presentations directly on our website;
  • protect form entries from robots;
  • monitor the performance of the site.

These third parties will collect and use your browsing data for their own purposes.

How to accept or reject cookies

When you start browsing an eZpublish site, the appearance of the "cookies" banner allows you to accept or refuse all the cookies we use. This banner will be displayed as long as you have not made a choice, even if you are browsing on another page of the site.

You can change your choices at any time by clicking on the "Cookie Management" link.

You can manage these cookies in your browser. Here are the procedures to follow: Firefox; Chrome; Explorer; Safari; Opera

For more information about the cookies we use, you can contact INRAE's Data Protection Officer by email at or by post at :


24, chemin de Borde Rouge -Auzeville - CS52627 31326 Castanet Tolosan cedex - France

Last update: May 2021

Menu Logo Principal Institut Agro Rennes-Angers

Home page

New concepts and technologies to increase protein feeding values for dairy cows

Determination of a new approach of proteins protection based on physic characteristics of particles and a new technique for estimating the value of food proteins.

Livestock farming has to face an increase of the demand of animal protein (milk and meat) especially in developing countries. On the other hand, it has to reduce its greenhouse gas, nitrate and ammonia emissions. A better efficiency of protein use is central for a more sustainable dairy production. A reduction of protein increases self-sufficiency and reduces nitrogen excretion, which impacts the environment such as eutrophication, acidification, due to ammonia and nitrate emissions (Van der Valt, 1988 ; Kay, 1969). A part of these emissions is linked to ruminal digestion by the microbial flora in dairy cows before intestinal digestion. To solve this problem, research has developed techniques to protect proteins and the most efficient technique was the tanning by formaldehyde, which is a reversible protection, found in 1975 (Vérité et al. 1977a et b). However, formaldehyde is a noxious molecule when used in firm therefore its utilization will be compromised in the years to come. This is why there is an interest for new techniques to protect proteins in feeds for cows to replace the tanning by formaldehyde.

3 vaches au pâturage

One option which hasn’t been considered until now to replace the formaldehyde technique is the influence of physical characteristics of particle (size, density…) on the residence time of feeds in the rumen. A rapid escape from the rumen will increase the probability to preserve proteins. As the efficiency of these new techniques of protection is difficult to evaluate using classical methods of feed evaluation, there is a need of a new methodology to evaluate the value of feeds.

Graine de soja

Towards new techniques of protein protection and new methodologies to estimate protein value

The objective of the thesis will be in the first place be to test the assumption that the physical characteristics (size, density…) of feeds particles play a role in the residence time of feeds in the rumen. Once these characteristics settled, they may be combined with one or several new techniques developed by feed industry to replace the tanning by formaldehyde. Concerning the new method of estimation of protein value of animal feed, it may be based on the response of milk protein synthesis and/or the amino acid blood rate of the cow after addition of the protected protein source in the diet of the cow.

The work will be divided in three parts:

  • The study of the physical characteristics of food particles (size, density) that would allow a rapid passage out of the rumen to limit their degradation.
  • The development of a new methodology for estimation of the protein value of feed. It will be based on the response of the production of milk protein with additional inputs of tested feed protein (integrating the variation of the response efficiency which makes this response is generally not linear).
  • Develop in collaboration with the partner (AGRIAL – feed producer) a new protein material protection technology by combining different existing technologies and data obtained on ruminal transit rate. This test will also allow a final validation of the methodology implementation.

Florence Dufreneix is working on this subject of thesis since the 1st january of 2016 for 3 years. She is supervised by Jean-Louis Peyraud and Philippe Faverdin in the team Dairy Systems.


Kay R. N. B. Digestion of protein in the intestines of adult ruminants. Symposium proceedings, 1969, Vol 28, p 140-151. [Full text]
Van der Walt J. D., Meyer J. H. F. Proteins digestion in ruminants. South African Journal of animal science, 1988, Vol 18, No 1, p 30-41. [Full text]
Vérité R., Journet M., Flechet J., Lefaivre R., Marquis B., Vérité M. Utilisation des tourteaux traités au formol par les vaches laitières. II. – Effets sur la production laitière du traitement des tourteaux et du niveau d’apport azoté au début de lactation. Annales de zootechnologie, 1977a, Vol 26, No 2, p 183-205. [Full text]
Vérité R., Poncet C., Chabi S., Pion R. Utilisation des tourteaux traités au formol par les vaches laitières. I. Aspects digestifs. Annales de zootechnies, 1977b, Vol 26, No 2, p 167-181. [Full text]


Florence Dufreneix florence.dufreneix[at] (PhD student)
Jean-Louis Peyraud jean-louis.peyraud[at] (supervisor – Inra)
Philippe Faverdin philippe.faverdin[at] (co-supervisor– Inra)
François Gautier f.gautier[at] (co-supervisor – Agrial)