Lars Erik Ruud defended his thesis on October 7th 2011

Ane Gro Siri Skjelfjord

The optimal free stall for dairy cows - effects of free-stall design on cleanliness, milk yield, health, and behaviour

Abstract from the thesis - PhD thesis 2011:42

Design of the free stall is of major importance to e.g. cleanliness and cow behaviour because the cows spend the majority of their time in the stalls, mostly lying but also standing. To avoid that cows chose to lie other places than in the free stalls, the design has to be such that it is the preferred place for lying. An implication of this is that the free stall has to be adapted to the demands of the cows. The main aim of this study was therefore to evaluate effects of free stall design on cleanliness, milk yield, health and behaviour. The thesis is based on three studies; one questionnaire about free stall base in 363 dairy herds, one field study in 232 dairy herds and one controlled preference test with 16 dairy cows. In present study it was found that soft stall bases with a minimum softness of 16 mm impact was associated with increased milk yield (+ 3.9 to 4.5 %), decreased incidence of clinical mastitis (up to 19.9 % reduction or 2.8 percent points) and teat lesions (up to 82.4 % reduction or 1.4 percent points), whereas concrete as lying surface seem to be a risk factor regarding removal. Present study also found that details of the free stall design are of importance for stall and animal cleanliness, factors influencing on udder health and milk quality. Clean stalls were associated with use of bedding (> 0.2 L per stall), maximum diagonal distance from rear curb in stall to neck rail of 1.96 m, lower head rail not present, length of stall base not more than 2.30/2.45 m, and brisket locator with maximum height 0.1 m should be used. However, the effect on stall cleanliness is minor if located more than 1.83 m from rear curb. Upper head rail should be positioned minimum 0.7 or preferably closer to 1.0 m above stall floor. Associations between stall cleanliness and stall width and length was found, however were of less importance than expected. It was found that an open front in free stalls is of importance for stall cleanliness, possibly because an open front will interfere less with the lying and raising movements of the cows. Further, the following variables were found to be risk factors for dirty cows; use of less than 0.5 L bedding per stall, less open front in the stall, increasing cow number per stall, less tame cows and high or low temperature and high relative air humidity. Flexible dividers performed equally good as standard fixed cantilever stall dividers with regard to lying behaviour of the animals in a controlled study comparing flexible and fixed stall dividers. The design of the stalls was based on the findings that contributed to increased stall and cow cleanliness mentioned above. The cows clearly preferred stalls with flexible dividers, however no differences in lying behaviour were found. The stalls remained remarkably clean during the experiment.

Updated: 07.10.11
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