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McLellan, Kathryn Jayne

University of British Columbia

Free-choice access to pasture allows cows to exert their own preference and may benefit lame cows by providing a softer and more comfortable lying and standing surface. However, the effect of this system on lameness has not yet been explored. The objective of this thesis was to investigate whether a 7-wk period of free-choice pasture access would improve lameness recovery and to document effects on lying behaviour, relative to control cows housed in the same group but not allowed outside. Lactating Holstein cows, all lame upon enrollment and housed inside a free-stall barn, were pseudo-randomly allocated to one of two treatments (balancing for gait score, parity, and previous lesion history, using rolling enrollment): free-choice access to pasture (n = 27; Pasture) or indoor housing only (n = 27; Indoor). Cows were gait scored weekly, by an observer blind to treatment, using a 5-point numerical rating system (NRS) from 1 = sound and NRS 5 = severely lame, and hoof inspections were performed by professional hoof trimmers at the start and end of the 7-wk period. Cows were categorized as sound (NRS ≤ 2 over 2 consecutive weeks) or lame, and lying behaviour was assessed using accelerometers. Cows with pasture access spent, on average, 15% of their time outdoors, with the majority of time spent outside between 1630 to 0700h (23% on pasture). Over the 7-wks, 42% of cows became sound; cows with pasture access were more likely to become sound and spent more time sound compared to cows kept only indoors (2.0 ± 0.34 vs. 0.81 ± 0.35 wk). Cows spent more time standing while on pasture versus when indoors (74% vs. 47%, respectively) and overall, cows with pasture access lay down for less time and tended to have fewer lying bouts than cows kept indoors. These results suggest that free-choice pasture access aids in lameness recovery. Future research is required to investigate longer-term effects of free-choice pasture access on the recovery of hoof lesions and re-occurrence of lameness cases in dairy cows.

Text

2021-08-26

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/79472

Applied Animal Biology

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/