Serum amyloid A concentrations in lungs and blood in calves with respiratory disease: association with clinical signs

Abstract

Bovine respiratory disease (BRD) is a multifactorial disease complex that causes major economic losses to farmers worldwide due to high morbidity and mortality. Several viral agents are considered to be primary cause of BRD, but more often than not, secondary bacterial agents are involved in the disease. Mycoplasma are also a major agent in BRD as primary or secondary factor. Environment plays a role as a catalyst to the disease. The present study was done to investigate the correlation of serum amyloid A (SAA) measured from tracheobronchial lavage (TBL) and clinical signs of BRD as well as the correlation of SAA measured from TBL fluid and SAA measured from blood serum. Samples were collected and clinical examination was performed in 10 calves during two times three weeks apart from 40 herds in all-in all-out calf-rearing farms in Finland. In total study included samples from 396 calves. Only those samples where all information was available were included in this study (450 samples, 234 from the first and 216 from the second time). There was significant positive association found between serum amyloid A measured from tracheobronchial lavage fluid and nasal discharge during the 1st sampling time. During the 2 nd time sampling nasal discharge was not significant anymore but fever showed tendencies of positive association. SAA measured from serum was higher during both sampling times compared to SAA measured from TBL fluid. Local and systemic SAA did not correlate.

Veiste hingamisteede haigus (bovine respiratory disease, BRD) on paljude põhjustega haiguste kompleks, mis põhjustab suure haigestumuse ja suremuse tõttu põllumajandustootjatele kogu maailmas suurt majanduslikku kahju. BRD peamiseks põhjuseks peetakse mitut viirustekitajat, kuid enamasti on haigusega seotud sekundaarsed bakteriaalsed tekitajad. Ka mükoplasmad on primaarse või sekundaarse tegurina olulised BRD tekitajad. Keskkond mängib rolli haiguse katalüsaatorina. Käesolevas uuringus määrati hingamisteede haigusega vasikate trahheobronhiaalse loputuse (TBL) vedeliku ja vere seerumi amüloid A (SAA) sisaldus ning selgitati nende võimalikke seoseid esinevate kliiniliste tunnustega. Samuti uuriti lokaalse ja süsteemse SAA omavahelist seost. Proovid koguti ja kliiniline läbivaatus viidi läbi 10 vasikaga 40 karjast 38 Soome vasikakasvatusfarmis kahel korral kolme nädalase vahega. Kokku oli uuringus 396 vasikat. Antud uuringusse kaasati nende vasikate proovid kellelt oli olemas täielikud andmed (kokku 450 proovi, 234 esimesest ja 216 teisest korrast). Esimesel proovivõtul leiti märkimisväärne positiivne seos TBL vedeliku SAA ja ninanõre esinemise vahel. Sellist seost ei ilmnenud teisel proovivõtmise ajal, kuid siis oli palavikuga esinemisega olulisusele lähedane positiivne seos. Seerumist mõõdetud SAA oli mõlema proovivõtu ajal kõrgem võrreldes TBL vedelikust mõõdetud SAA-ga. Lokaalne ja süsteemne SAA ei olnud omavahel seoses.