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Viability of waste milk pasteurization systems for calf feeding systems


The objective of this study was to determine amount and composition of waste milk (WM) generated by 13 dairy farms and to measure effectiveness of on-farm pasteurizers. Waste milk was sampled bi-weekly from three farms located in North Carolina (NC) for 28 weeks and twice from ten farms in California (CA) in June 2005 and Jan. 2006. Farms ranged in size from 530 to 7000 milk cows and included a 30,000 head calf ranch. Amount of waste milk generated ranged from 2.48 – 9.84 L/calf/d. Standard plate count (SPC) of waste milk before pasteurization averaged 17 million cfu/ml on NC farms and 1.6 million cfu/ml on CA farms. Fat and protein from NC farms averaged, 3.5 and 3.2%, while CA farms averaged 4.0 and 3. 8%. Pasteurizer performance was evaluated based on SPC and alkaline phosphatase activity. Pasteurizers failed to deactiv ate alkaline phosphatase in 16%, and <5% of the time in NC and CA. California WM had lower post pasteurized SPC (13,000 cfu/ml) than NC farms (430,000 cfu/ml) A feeding trial was conducted to evaluate supplementing WM with 28% protein: 20% fat milk replacer (28:20) when WM is insufficient relative to calf demands. Calves were fed a combination of milk (M) and (28:20). Milk replacer was reconstituted at 14% DM, so that diets were isocaloric. Treatm ent (TRT) 1 calves received M for 28d and then 28:20 until weaning at 56d. Treatment 2 calves received 28:20 for 28d and then milk until weaning. Treatment 3 calves received 28:20 for the entire period. Liquid diets were fed twice daily at the rate of 5.5, 7.3 and 8.2 kg/d as fed for birth weights of <27, 27 -36 and 36<kg to provide enough energy and protein for 0.5, 0.8 and 1.0 kg/d gain . Calf body weight (BW), wither height (WH), hip heig ht (HH), hip width (HW), body length (BL), and heart girth (HG) were recorded at 1d, 28d ±3d, 35d ±3d, and 56d of age. Four periods of time were evaluated; the total period, first four weeks (P1), transition period (TP), in which calves were switching diets, and until weaning (P2). Body weight, WH, HH, HW, BL and HG gain were not different between treatments over the total period. Similarly, grain intake through 8 weeks was not different. Treatment 1 ADG was higher during TP as compared to TRT 2, which could be due to increased water retention from higher mineral content of 28:20 relative to M diets. Results of the trial demonstrated that similar growth rates through 8 weeks of age was achieved with either combination of M and 28:20 or only 28:20 when fed on an isocaloric basis.


Michael Chase Scott

Thesis submitted to the Faculty of Virginia Polytechnic Institute and State University for partial fulfillment of the requirements for the degree of Master of Science in Dairy Science (Management)

Robert E. James, Chair
Michael L. McGilliard
John F. Currin