Milk pH and heat stability of heifers fed sorghum and tannic acid levels

The introduction of food containing phenolic compounds (tannins) in animal feeding can give many benefits as antioxidants in biological systems and food products, and still have antimicrobial effects on plasma lipid deposition, muscle and visceral factors that can alter the life span milk and dairy products. This research objective was to evaluate the milk pH and heat stability of crossbred heifers fed ground sorgh um and tannic acid levels. The experiment was conducted in the Animal Science cattle sector from the Department of Agricultural Sciences Center UFPB, Campus II, Areia - Paraíba Brazil. Was used 05 crossbred heifers Dutch / Zebu in similar ages, stage of lactation and production. The treatments consisted of 6 kg of feed containing; 3kg sorghum, 1kg of corn, 1.5kg of soy and 0.5kg of wheat, and 0%, 1.3%, 2.6%, 3.9% and 5.2% tannic acid adding, and forage was offered corn silage. The treatments were constituted by a 5x5 Latin square design, each treatment consisted of 20 days, totaling 100 days. The milk was collected at the final of each square time, pasteurized and stored in bottles at the refrigerator. The heat stability was performed adding solutions made by ethanol and distilled water to the milk. The analysis of pH and heat stability were performed daily. The pH analyzes were stable during 10 days that remained in the refrigerator after pasteurization, falling on average 0.06 points to the last evaluation date, the samples pH average was 6.64, this pH indicates a high quality milk. The heat stability fell down by 5% over the period of 10 days of storage, where all started stable in solution of 85% on day 10 and 80%, with no difference between treatments. The results demonstrate that treatment with tannin didn't influenced the stability by heat or pH of the analyzed heifers milk, and that milk produced by them have an excellent quality, above the recommended by the Brazilian agriculture ministry that is 72%.