Bu çalışma 10 adet pnömonili (Deney grubu I) ve 10 adet basit indigesyonlu (Deney grubu II) sığırlarda plazma tiamin HC1 konsantrasyonlarında değişiklikleri belirlemek amacıyla yapıldı. 10 adet sağlıklı sığır kontrol grubu olarak kullanıldı. Deney grubu I'deki hayvanlarda klinik olarak anoreksi, depresyon, solunum sayısında artış, muko-purulent burun akıntısı, öksürük, bronko-alveoler seslerde artış ve ruminal hareketlerde azalma gözlendi. Deney grubu Il'deki hayvanlarda en önemli klinik semptomlar anoreksi, depresyon, ruminasyon ve ruktusun olmaması ve retikulo-ruminal hareketlerde azalma idi. Her iki gruptaki sığırların ruminal sıvı bakteri ve protozoa sayısı önemli derecede azalmıştı (p

This study was carried out to determine alteration of plasma thiamine concentration in ten adult cattle with pneumonia (Experimental group 1) and ten adult cattle with simple indigestion (Experimental group II). Ten healthy cattle were used as a control (Control group). The experimental group I cattle showed anorexia, depression, increased respiration rate, muco-purulent nasal discharges, coughing, increased bronchio alveoler sounds, impaired ruminal motility. The most pronounced clinical findings in experimental group II cattle were anorexia, depression, no rumination and eruction and decreased reticulo-ruminal movements. The counts of bacteria and protozoa of ruminal fluid in both experimental group 1 and II significantly decreased (p<0.001). Plasma thiamine HO concentrations were also found to be significantly reduced in both experimental groups of cattle. The mean plasma thiamine HC1 concentrations in healthy cattle was 1.70 $\mu$ g/ml, while the plazma thiamine HC1 concentrations in experimental groups I and II were found to be 1.00 $\mu$ g6ml and 0.50 $\mu$ g/ dl, respectively. The result of the study showed that thiamine supplementation is to be consider as part of the treatment of simple indigestion and pneumonia.