Production and Characteristics of Manure from Lactating Dairy Cows in Florida

Abstract

Total quantities of urine and feces excreted daily were collected from 12 lactating Holstein dairy cows averaging 567 kg (1250 lb) on fixed feed intake averaging 20 kg (44 lb) of dry matter per day, or 16 kg (36 lb) of dry matter per day per 454 kg (1000 lb) of body weight. Amounts of total and volatile solids, acid detergent lignin, phosphorus in feces, and phosphorus in urine were determined. Cows excreted an average of 44.6 kg (98.1 lb) of raw waste, 6.08 kg (13.1 lb) of total solids in feces, and 0.16 kg (0.3 lb) of fixed solids in feces daily, expressed per 454 kg (1000 lb) of body weight. Total solids of feces represented 36.4% of the daily diet dry matter intake. These values are greater than table values developed by previous researchers and used to design dairy farm facilities. Feces to urine ratio (w/w) ranged from 1.4:1 to 1.9:1. Fecal grab samples (n = 383) from cows on commercial dairies, for which estimated daily intake of feed was available, had greater acid detergent lignin content (16.9 vs. 13.8%) and about 60% more than cows on the total collection trial (4.2 vs. 2.6%), perhaps due to some ingestion of sand on pasture. For all fecal samples fixed solids percentages were much less than table values developed by previous researchers. Differences may be due, in part, to improved genetic potential of cows, because of increased feed intake, climate, or intensive management practices. Our research also confirmed that the quantity of phosphorus (P) excreted in feces was variable, but depended on intake of dietary P.