Stärkelsenedbrytningens betydelse för mjölkkors konsumtionsmönster och mjölkproduktion
Feed intake in dairy cows is regulated by a variety of factors influencing hunger and satiety.
One of the regulation systems includes the short chain fatty acids produced during feed
degradation in the rumen. Starch can be digested either in the rumen where short chain fatty
acids are produced or in the small intestine where glucose is the end product. Since glucose
does not have the same effect on satiety that short chain fatty acids have, the site of starch
digestion might be an important factor that affects feed intake and milk production. The aim
of this study was to investigate the effects of site of starch digestion on feeding behaviour
(feed intake, consumption time, and eating frequency) and milk production.
Because feeding behaviour is closely connected to the cows? environment, the study also
included observations of behaviour.
Three different feed rations were compared. They were all total mixed rations that were
formulated to have the same nutritional composition except for the ruminal starch
degradability. To achieve three different levels of ruminal starch degradability different starch
sources were used:
? Feed A: Wheat, barley and oats ? 92 % ruminal starch degradation
? Feed B: Wheat, barley and maize ? 76 % ruminal starch degradation
? Feed C: Maize and peas ? 61 % ruminal starch degradation.
The experimental design was a change-over design with three periods using 48 dairy cows in
mid-lactation. To get information about individual feeding behaviour, special feeding
equipment was used that automatically registered all feeding visits that the cows performed
during the experiment. The visits within a derived time-span were first grouped into meals,
and then feeding behaviour was studied per meal and per day (24 h). Data were analysed with
an Analysis of Variance (Mixed Effect Model, SAS vers. 8.2). During the later part of the
feeding trial two different behaviour studies were made. One study included the cows?
activity and the other was a study of the cause of cows terminating feeding visits.
Feed intake per meal was not significantly affected by treatment but there were significant
period effects (p