Date Published: August 28, 2019
Publisher: Public Library of Science
Author(s): Jessie A. Kull, Katy L. Proudfoot, Gina M. Pighetti, Jeffery M. Bewley, Bruce F. O’Hara, Kevin D. Donohue, Peter D. Krawczel, Juan J Loor.
The objective was to determine the effects of sleep or lying deprivation on the behavior of dairy cows. Data were collected from 8 multi- and 4 primiparous cows (DIM = 199 ± 44 (mean ± SD); days pregnant = 77 ± 30). Using a crossover design, each cow experienced: 1) sleep deprivation implemented by noise or physical contact when their posture suggested sleep, and 2) lying deprivation imposed by a grid placed on the pen floor. One day before treatment (baseline), and treatment day (treatment) were followed by a 12-d washout period (with the first 7 d used to evaluate recovery). Study days were organized from 2100 to 2059. During habituation (d -3 and -2 before treatment), baseline (d -1), and trt (d 0), housing was individual boxstalls (mattress with no bedding). After treatment, cows returned to sand-bedded freestalls for a 7-d recovery period (d 1 to 7) where data on lying behaviors were collected. Following the recovery period, an additional 5-d period was provided to allow the cows a 12-d period between exposures to treatments. Daily lying time, number lying bouts, bout duration, and number of steps were recorded by dataloggers attached to the hind leg of cows throughout the study period. Data were analyzed using a mixed model including fixed effects of treatment (sleep deprivation vs. sleep and lying deprivation), day, and their interaction with significant main effects separated using a PDIFF statement (P ≤ 0.05). Interactions between treatment and day were detected for daily lying time and the number of bouts. Lying time was lower for both treatments during the treatment period compared to baseline. Lying time increased during the recovery period for both lying and sleep deprived cows. However, it took 4 d for the lying deprived cows to fully recover their lying time after treatment, whereas it took the sleep deprived cows 2 d for their lying time to return to baseline levels. Results suggest that both sleep and lying deprivation can have impact cow behavior. Management factors that limit freestall access likely reduce lying time and sleep, causing negative welfare implications for dairy cows.
Lying time is critical for biological function for dairy cows, however, there are various factors on-farm that reduce a cow’s ability to lie down or influence how she uses her lying space. Management factors such as overstocking  or heat stress  decrease lying time, either by reducing access to lying spaces or altering the cow’s motivation to lie down. Additionally, facility factors such as bedding type  and stall design , can influence how a cow uses a lying stall. The impact of facility design on lying time has been well-studied, but less is known about the quality of rest cows are able to maintain while lying down. A measurement of rest quality in cattle and other species is sleep, but very little research has assessed sleep in dairy cattle.
This study was the first to evaluate the effects of sleep and lying deprivation on behavior and milk production, which has not been well investigated in dairy cows. Previously, research has focused on the effects of lying deprivation on dairy cows, but has failed to consider the cumulative effect of lying and sleep deprivation during this time. Assessing the effects of sleep and lying deprivation separately is inherent to understanding the difference between gross quantity of lying time, and what she is doing while she is lying. Within the current study, both deprivations altered lying time after treatment, suggesting either deprivation could alter cow behavior and welfare. Only the direct limitation of lying time through the use of the wooden grid reduced the time cows spend in the various vigilance states. Furthermore, although sleep deprivation had no effect on milk production, the combination of sleep and lying deprivation reduced milk yield.
Collectively, these data suggest that lying deprivation induces concurrent sleep deprivation, which has an additive, detrimental effect on the behavior and productivity, both yield and quality, of lactating dairy cows. This suggests that sleep deprivation may be one of the mechanisms explaining the decreases in productivity associated with reduced lying times. The limited effect on sleep resulting from the sleep deprivation treatment reinforces the hypothesis that cows can enter various vigilance states in a wide range of lying postures. This remains a critical question to address in order to evaluate management practices that reduce the potential quality of lying, such as poorly designed or managed lying areas, from those that reduce access to lying resources, such as overstocking or excessive use of headlocks or time in the holding area of milking parlors.