The effects of using acidogenic Top Chlor in close-up dry period on urine pH, blood calcium concentration and spectral peak bands of chlorine ion with protein fraction

Adding anions from anionic salt such as calcium chloride, ammonium chloride, calcium sulfate and magnesium sulfate to the prepartum diet reduced the incidence of postpartum hypocalcemia in dairy cow but reduced feed intake. Top Chlor ™ is an acidifying coproduce which inducing mild metabolic acidosis and improving the palatability of prepartum diet. This study was conducted to evaluate the effects of Top Chlor ™ on urine pH, blood calcium concentration and chlorine ion binding with protein fraction of feed. Close-up cows (255 days of gestation) in a dairy farm, were randomly divided into two groups of control (non-anionic salt, n=30) and treatment (Top Chlor ™, n=30). Urine and Serum samples were collected before calving and also at the time of partition, 24 and 48 hours after calving. Molecular structural changes of Top Chlor ™ were studied by infrared spectroscopy and X-ray diffraction. The data were analyzed by mixed procedures of SAS software. The urine pH of cows that consumed Top Chlor™ decreased significantly (6.56 vs. 8.15, P<0.05). Cows that fed Top Chlor ™ before calving had higher blood calcium concentrations within 24 hours of calving (8.38 vs. 7.32 mg/dl, P<0.05). Serum phosphor concentration decreased in cows receiving control diet at 24 hours before calving (4.48 vs. 5.97 mg/dl, P <0.05). Serum magnesium concentration was not significant (P˃0.05). X-ray diffraction analysis showed that organic structures and amino acids were coordinated with magnesium in 6-aqueous magnesium complexes with different states. Also, the molecular structure studies showed that during the processing of Top Chlor™, free NH2 compounds in amino acid structures bonded with chlorine ions and NH3Cl complex was formed. The results of the study showed that the Top Chlor™ has a suitable acidifying power and this improved the postpartum blood calcium concentration of dairy cow. Also, the results of FTIR showed that chlorine ion has bonded with the protein part of the feed.