Final answer:
The most likely cause of an increase in fibrinogen levels in cattle is inflammation, which leads to a natural increase in this clotting protein to help form blood clots in response to injury or infection.
Step-by-step explanation:
An increase in fibrinogen relative to the other plasma proteins in cattle is most often associated with inflammation. Fibrinogen is converted into fibrin during the process of coagulation, which forms a mesh capturing more platelets and erythrocytes to create a clot. This is a natural response to injury but can be exploited by pathogenic bacteria like Staphylococcus aureus, which can produce coagulase that triggers clot formation and helps the bacteria evade the immune response.
Pregnancy can also induce changes in the blood composition, which may lead to certain inflammatory responses, but a significant increase in fibrinogen levels is more directly indicative of inflammation.
The liver produces fibrinogen, accounting for about 7% of total plasma protein volume, and is essential for the clotting process. Therefore, this increase is not primarily related to issues such as inadequate production of heparin or clotting factors, excessive production of platelets, or insufficiency of other blood components like albumin or immunoglobulins.