*4.3.1.5. Haptoglobin*

*4.3.1.3. Alpha1*

Alpha<sup>1</sup>

Alpha<sup>1</sup>

*4.3.1.4. Serum amyloid A*

viral diarrhea virus [166, 167].

*-fetoprotein*

116 Ruminants - The Husbandry, Economic and Health Aspects

metabolism of bilirubin [150, 151].

substances and immune factors, including alpha<sup>1</sup>



Smith et al. [152] have demonstrated that the concentrations of AFP in fetal bovine plasma reach the highest values in the 3–4th of fetal period, which is followed by significant decrease until birth. A decrease of the values of AFP in the first hours of life was obtained by Bader et al. [149] that may represent the physiological effect on the fetal tissues changing from an intrauterine to an extrauterine environment, with decrease in the production of fetal proteins in the liver. Lee et al. [153] concluded that following the initial decrease of the values of AFP within hours after birth, the concentrations of AFP tend to stabilize during the rest of the first week, and then decrease rapidly. On the other hand, Tóthová et al. [122] found a marked increase of AFP concentrations 1 day after colostrum intake, with following gradual decrease of values up to day 30 of life. The relatively higher values of AFP after birth may be associated with its synthesis (not ceasing entirely at birth) by fetal hepatocytes that continue during the early postnatal period [154]. Furthermore, colostrum contains many non-nutrient

the increased concentrations of AFP in calves 1 day after colostrum intake [155].

medicine, the possible use of AFP as disease marker was not yet evaluated.


Serum amyloid A (SAA) is a small hydrophobic protein that belongs to the family of apolipoproteins associated with high density lipoprotein [157]. Different isoforms of SAA are expressed constitutively at different levels in response to inflammatory stimuli [158]. During inflammation, SAA1 and SAA2 are expressed principally in the liver, whereas SAA3 is induced in many distinct tissues, including the mammary gland [159]. The fourth isoform, SAA4, does not respond to external stimuli [160]. The main functions of SAA are the reverse transport of cholesterol from tissue to hepatocytes, opsonization, inhibition of phagocyte oxidative burst, and platelet activation [136]. The M-SAA3 isoform found in colostrum stimulates the production of mucin from intestinal cells and thus helps to prevent bacterial colonization [161].

In ruminants, SAA belongs to major acute-phase proteins which increases more in acute rather than in chronic conditions [162]. Intense changes in the concentrations of SAA were reported in dairy cows with various inflammatory diseases, including cows with endometritis, mastitis, as well as in lame cows [163–165]. It was raised also in cattle experimentally infected with *Mannheimia haemolytica* and bovine respiratory syncytial virus, or with bovine Haptoglobin (Hp) is a glycoprotein that consists of two α and two β chains, connected by disulfide bridges [173]. In the circulation, Hp is highly polymerized, having a molecular weight of approximately 1000–2000 kDa, and exists also as a polymer associated with albumin [174]. The primary function of Hp is to bind free hemoglobin released from erythrocytes and thereby inhibits its oxidative activity [175]. The Hp-hemoglobin binding also reduces the availability of the heme residue from bacterial growth [176].

Many studies have indicated the significance of Hp as a clinically useful parameter for measuring the occurrence and severity of inflammatory responses in cattle with various diseases, including mastitis, enteritis, peritonitis, pneumonia, as well as endocarditis [136, 177]. Higher concentrations of Hp were found also by Sheldon et al. [178] in cows with uterine bacterial contamination. In addition, Hp was detected in ewes as prognostic indicator of ovine dystocia [179]. Gonzalez et al. [180] studied the possible use of acute-phase proteins as markers of subacute ruminal acidosis in goats. They found a moderate increase of Hp concentrations during the induction period, while SAA did not change. In a further study, Gonzalez et al. [181] determined the effect of fasting-induced pregnancy toxemia on the concentrations of acute-phase proteins in goats. They found a significant increase only in the concentrations of Hp, but not in other acutephase proteins. The changes of some inflammatory markers were evaluated also in goats around kidding [182]. Their results suggest that an increase of inflammatory indicators (mainly Hp) before kidding may be related to the changes in the energy balance status around parturition.
