Mesquite pod meal as an additive increases milk total solids, lactose, fat and protein content in dairy cows

The objective was to evaluate the intake, digestibility, milk yield and composition of cows fed mesquite pod meal (MPM). Five crossbred dairy cows, with an average body weight of 450 ± 5 kg and producing 10 ± 1 kg of milk/day were distributed in a 5 × 5 Latin square arrangement with five periods of 20 days each, comprised of 15 days for adaptation to the experimental diets (T1 = 0%, T2 = 1.5%, T3 = 3.0%, T4 = 4.5% and T5 = 6.0% MPM) and 5 days for data collection. Variables were assessed by analysis of variance and regression at P < 0.01 and P < 0.05 of significance, using the Student's test. Animals were kept on pastures and the concentrates were provided at 6 kg/animal divided in two meals per day. The inclusion of 3.0% mesquite pod meal did not affect the intake, digestibility of nutrients and milk yield, but it changed milk composition. The dietary inclusion of 3.0% mesquite pod meal as a palatability enhancer increases the percentage of milk solids, lactose, fat and protein. Therefore, mesquite pod meal can be included in diets for dairy cows to improve the nutritive value of milk.

Daily ingestion of tetracycline residue present in pasteurized milk: a public health problem

The objective of this study was to evaluate (qualitatively and quantitatively) the occurrence of antibiotic residue in pasteurized milk in Brazil. Pasteurized milk samples (n = 252) were collected monthly from Nov. 2010-Oct. 2011 from 21 commercial establishments (brands). A screening test (Delvotest® SP-NT) was applied to those samples. In positive (n = 19) and/or suspect samples (n = 24), we quantified oxytetracycline (OTC) and tetracycline (TC) by high-performance liquid chromatography with diode array detector (HPLC-DAD). OTCs were detected in all positive samples and TCs in six. In the 24suspected samples, OTCs were detected in 23 and TCs were not found in 8. Of the milk brands evaluated (n = 21), the presence of antibiotic residue was not detected in 4; in the other brands, both positive and suspect samples were verified. Results indicate the presence of antibiotic residue above legal limits. According to actual milk consumption in Brazil (441 mL/kg BW/day), in only 9 of the 17 brands of milk with antibiotic residue, the estimated daily intake was at or less than the maximum recommended by the European Union. The screening test used was effective to identify the presence of antibiotic residue (OTC and TC), confirmed by HPLC-DAD. The OTC is the predominant antimicrobial used by dairy farmers. Ingestion of contaminated milk by OTC and TC can increase the resistance of microorganisms to antibiotics.