When and where do dairy cows defecate and urinate?

The accumulation of urine and feces can be responsible for many cow and environmental problems. Despite this, little is known about the factors affecting defecation and urination. In the first experiment, the occurrence of defecation and urination behaviors of 48 lactating Holstein cows was observed [days in milk (DIM)=144.7±38.0 d, body weight (BW)=667.1±72.0kg, parity=2.8±2.3] in freestalls over 48h. In the second experiment, defecation and urination by 29 lactating Holstein dairy cows were observed (DIM=62±22.1 d, BW=590±70.0kg, parity=2±1.3) in another freestall barn over a period of 5 d and related to cow activity and feeding behavior. In both experiments, based on total occurrence of eliminative behaviors, cows mainly defecated (experiment 1: 33.4±2.0%; experiment 2: 42.3±3.1%) and urinated (experiment 1: 28.2±2.5%; experiment 2: 42.7±4.0%) in the feed alley and while occupying a stall (defecation: experiment 1: 28.5±1.0%; experiment 2: 26.2±3.0%; urination: experiment 1: 42.2±1.5%; experiment 2: 39.9±3.8%). Occupying a stall included lying, standing in the stall, or standing with 2 feet in the stall and 2 feet in the alley. In both experiments, differences were found between cows in frequency of defecation (experiment 1: 9.8±4.2/d, range=3 to 20; experiment 2: 15.4±4.3/d, range=6 to 36) and in frequency of urination (experiment 1: 7.0±3.1/d, range=2 to 18; experiment 2: 9.3±2.8/d, range=3 to 19). Large differences between cows were observed in the frequency of defecation and urination, but these were not correlated with parity, milk production, BW, DIM, or dry matter intake.