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Mass Balance of Nitrogen Loading <br /> Nitrate loading calculations for properties: <br /> Definition:Au is the abbreviation for animal unit.One animal unit represents 1000 lbs. of body weight. <br /> Nitrogen content of manure from dairy cattle: <br /> Classification of cow: Lbs. N per Au <br /> Lactating cows . 56 lbs. <br /> Dry cows&Bred heifer .45 lbs. <br /> Heifers .45 lbs. <br /> Calves .45 lbs. <br /> Baby calves .45 lbs. <br /> Animal units for typical Holstein dairy cattle,generally accepted by the State Water Quality Control Board: <br /> Lactating cow 1.4 Au's <br /> Dry cow/breed heifer 1.12 Au's <br /> Heifer(1 yr:bred) 1.02 Au's <br /> Calves(3 mo,1 yr.) .49 Au's 'l <br /> Baby calves .29 Au's <br /> Nitrogen Production Calculations <br /> Projected animal units: Animals A.U.'s each A.U.'s <br /> Lactating cows 3000 1.4 4200 <br /> Dry cows and bred heifers 2073 1.12 2322 <br /> Heifers(1 yr,breeding) 528 1.02 539 <br /> Calves 1585 0.49 777 <br /> Baby calves 528 0.29 153 <br /> Nitrogen Production <br /> Flushed Freestdls <br /> Type of Animal A.U.'s Ib of N/day N/day <br /> Lactating cows 4,200 0.56 2,352 <br /> Dry cows and bred heifers 0 0.45 0 <br /> Heifers(1 yr:breeding) 0 0.45 0 <br /> Calves 0 0.45 0 <br /> Baby calves 0 0.45 0 <br /> Total lbs. N per day before losses 2,352 <br /> Flushed Feed Lane <br /> Lactating cows 0 0.56 0 <br /> Dry cows and bred heifers 2,322 0.45 1,045 <br /> Heifers(1 yr:breeding) 539 0.45 242 <br /> Calves 777 0.45 349 <br /> Baby calves 153 0.45 69 <br /> Total lbs.N per day before losses 1,706 <br />