The 24-h time budget (Figure 3) represents the net behavioral response of a cow to her social and physical environment (Grant, 2004). Deviations from benchmarked behavioral routines reflect departures from natural behavior and may serve as a basis for estimating DMI, performance, health and economic losses due to inadequate management strategies. Dairy cows at approximately100 percent stocking density in free-stall housing spend 3 to 5 hours per day feeding, consuming 9 to 14 meals per day. In addition, they ruminate 7 to 10 hours per day, spend approximately 30 minutes per day drinking, 2 to 3 hours per day outside the pen for milking and other management practices and require approximately10 to 12 hours per day of lying time (Grant and Albright, 2001). There are three important management considerations regarding time budgets: • Approximately 70 percent of the cow’s day is spent eating and/or resting, so we cannot afford to screw it up • There are only 24 hours in a day • Consequently, the cow only has, on average, 2.5 to 3.5 hours per day to spend outside the pen and away from the feed, water and stalls. If we force the cow to spend more than this time outside the pen, then she will need to give up something – typically feeding and/or resting. Every farmer should know how long their cows spend outside the pen in a free-stall barn. Recently, Gomez and Cook (2010) have shown how time outside the pen during milking and lameness interact to affect the cow’s daily time budget. For example, lameness score 3 cows (1 to 3 scale) with a mattress stall base may only be outside the pen for approximately 0.5 to 1.5 hours per day and still meet their requirement for 11-12 hours per day resting time (based on Figure 3 with mattress systems in Gomez and Cook, 2010). In contrast, lameness score 1 (healthy) cows can stay outside the pen from 2 to 4+ hours per day and meet their resting requirement. At some point, it becomes impossible to meet time budgeting requirements with lame cows. If they can only be outside the pen for 0.5 hours per day, for instance, then realistically there is not enough time for milking even twice daily. Common ways to disturb time budgets on-farm include: • excessive time outside the pen • mixing primi- and multiparous cows • overcrowding and resulting excessive competition • greater than 1 hour per day in headlocks, especially fresh cows • short pen stays during transition period – i. e. “social turmoil” • inadequate exercise • uncomfortable stalls • inadequate feed availability And the list could continue further… • 5.0 h/d eating • 12-14 h/d lying (resting) • 2.0-3.0 h/d standing, walking, grooming, agonistic, idling • 0.5 h/d drinking • 20.5-21.5 h/d total needed • 2.5-3.5 h “milking” = 24 h/d Figure 3. 24-hour time budget of a dairy cow. Time budgeting as a concept is easy to grasp. But, farmers often ask if time away from the pen really matters to the cow in any measurable way? In an on-farm case study, Matzke (2003) observed the effect of 3 versus 6 hours per day outside the pen. Pen size was adjusted versus parlor capacity to manipulate time outside the pen for milking. Mixed primi- and multiparous cows (30:70 ratio) at 100 percent stocking density of stalls and feed bunk were observed for 14-day periods. As much as possible, factors other than time outside the pen were kept constant. Figure 4 shows that cows gained over 2 hours per day of rest and nearly 5 pounds per day of milk when they were outside the pen for only 3 versus 6 hours per day. Incredibly, first-calf heifers gained 4 hours per day of rest and 8 pounds per day more milk. So, there appear to be short-term effects of time budgeting on milk yield that are associated with changes in resting activity. Failure to meet time budget needs may also affect longer term health status of the cow, such as lameness. In fact, the long term economic consequences of poor time budgeting may outweigh any shorter-term changes in milk yield. Espejo and Endres (2007) found that prevalence of lameness in 53 high-producing pens on 50 dairy farms was most highly associated with greater time outside the pen. Cow Comfort Economics: Minimizing time outside the pen is the key to optimal time budgeting. Meeting the time budget requirement for resting may result in greater milk yield (5 to 8 pounds per day more) and lower incidence of lameness.