Indices for estimation of dairy free-stall occupancy

Abstract: The objective of this study was to obtain variables that enabled estimation of variation in stall occupancy times based on the cow-to-stall ratio. First, stall use by Holstein–Friesian cows was analyzed on 16 farms in Galicia, Northwest Spain, by continuously recording cow behavior for 24h. Intervals of 17s were recorded every 3min and 30s. The video recordings were watched to count the number of simultaneously occupied stalls. Before actually reducing the number of stalls in practice, the variation in the average occupancy time per stall was estimated by using a variable termed ‘predictably altered time of occupancy’ for stall-to-cow ratios of 0.9, 0.8 and 0.7 (111%, 125% and 143% stocking density, respectively). Such an estimate was based on data for an occupancy level of 1.00stall/cow. The following variables were determined based on data obtained from the initial sample of 16 farms: maximum stall occupancy, average occupancy time per stall, average stall occupancy time per cow, and predictably altered time of occupancy. Three farms were selected from the initial sample. On such farms, 0.8 and 0.7stall/cow ratios were actually applied to verify the estimates of variation. Other additional variable was determined for the three selected farms: occupancy time at different levels of stall occupancy. The results for a stall-to-cow ratio of 0.7 (143% stocking density) suggested considerable alterations in occupancy time per stall, evidenced by maximum stall occupancy. Such alterations had already been detected from estimates of the predictably altered time of occupancy and were confirmed in practice. The effects of the 0.9 ratio (111% stocking density) were lower because maximum stall occupancy did not exceed 90% on the farms studied. Because the use of intermediate values, such as 0.8stalls/cow (125% stocking density), can cause trouble in barns with average occupancy levels above 50%, monitoring individual cows with special conditions such as heifers becomes essential. The theoretical determination of the time of occupancy predictably altered by the proposed reduction in the number of stalls is an indicator of the effect of such a reduction on stall use. The predictably altered time of occupancy can be determined for a specific herd, management system and barn based on a ratio of 1.00cow/stall. [Copyright &y& Elsevier]