Dairy cow defecation and urination frequency and spatial distribution in relation to time-limited grazing Frank W. Oudshoorn a, ⁎ , Troels Kristensen b , Esmaeil Shahrak Nadimi a a Aarhus University, Faculty of Agricultural Sciences, Department of Agricultural Engineering, Schüttesvej 17, DK-8700 Horsens, Denmark b Aarhus University, Faculty of Agricultural Sciences, Department of Agroecology, Research Centre Foulum, P.O. Box 50, DK-8830 Tjele, Denmark Received 11 May 2006; received in revised form 22 February 2007; accepted 22 February 2007 Abstract The objective of this paper was to investigate the effect of limited grazing time on urination and defecation frequency, spatial distribution of excrement in the paddock, and the resulting nitrogen balance at animal and field level. During a 6-week period in early summer, 60 Holstein Frisian dairy cows (31.0 ± 5.4 kg ECM) were randomly allocated to three different treatments, with grazing at clover-grass pasture during daytime for 4, 6.5 or 9 h daily. Indoor feeding, with a mixture of roughage and concentrates (13% crude protein), was restricted for treatment 4 and 6.5 h to the amount the 9-h treatment could eat. Cows allowed grazing at pasture for 4 h moved more rapidly during pasture, moved longer distance per active hour and used a higher proportion of the time eating, both at pasture and indoor, than the cows allowed longer time at pasture. Limiting the grazing time had no influence on the urination (mean = 0.26) and defecation (mean = 0.37) frequency per cow per hour during pasture. Even though the proportion of time active (eating, drinking, standing or walking), and the actual time active during pasture was different for the treatments, the frequency of urination and defecation per active hour was also unaffected by the treatments. Urine and faeces were distributed in the pasture, without specific hot-spots. The estimated daily N-balance at animal level showed increased N excretion with time at pasture. Assuming that excretion follows the active periods during the day and 7000 kg DM foliage is available on yearly basis, this would result in total excretion at field level of 58, 86 and 108 kg N per ha respectively for treatment 4, 6.5 and 9 h. The results of this experiment show that it is possible to reduce the nitrogen excretion in a grazing system by restricting the grazing time of dairy cows together with restricted indoor feeding while maintaining high foliage intake. © 2007 Elsevier B.V. All rights reserved. Keywords: Time-limited grazing; Nitrogen excretion; Urination frequency; Defecation frequency; Spatial distribution; Time budget 1. Introduction Pasturing high-yielding dairy cows increases the potential risk of nitrate leaching, in comparison with zero grazing and barn feeding of roughage (Eriksen et al., 2004). Surplus nitrogen can be high because of high stocking rates, excessive fertilization without taking animal manure deposition in account, or the presence of ‘hot-spots’ (non-uniform excretion), where animals gather and tend to urinate or defecate more than average (Eriksen and Kristensen, 2001; White et al., 2001; McGechan and Topp, 2004). High stocking rates could arise due to shortage of land around the barn. The demand for documentation of mineral budgets, the extra Available online at www.sciencedirect.com Livestock Science 113 (2008) 62 – 73 www.elsevier.com/locate/livsci ⁎ Corresponding author. Tel.: +45 89993106; fax: +45 89993100. E-mail address: FrankW.Oudshoorn@agrsci.dk (F.W. Oudshoorn). 1871-1413/$ - see front matter © 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.livsci.2007.02.021