Under normal weather conditions, dairy cows are inclined to access dry-lying surfaces, but winter conditions may limit the opportunity when cows are managed outdoors. In this current research, researchers highlight how bad weather affects the welfare of cows, pinpointing key management areas of focus.
Winter can be an unforgiving time of survival when animals face the howling, chilling winds. To give your cattle the best chance of staying healthy and surviving, one must know the extent of damage winters can inflict on animal welfare.
The amount of time that cows spend lying is an important welfare indicator. Longer lying times often suggest more comfortable lying surfaces. Shorter lying times can be a risk factor for lameness in grazing cows and can affect the functioning of the pituitary-adrenal axis, leading to increased chronic stress. In addition, muddy conditions can result in poor walking surfaces that limit movement and can be energetically costly.
Outdoor management of dairy cows during the winter on crop paddocks, such as kale or fodder beet, is a management strategy used in some parts of the world with pasture-based systems.
In this study, published in the Journal of Dairy Science, researchers from AgResearch Ltd. and DairyNZ Ltd., New Zealand, allocated nonlactating pregnant dairy cows to paddocks with either fodder beet or kale (2 groups each) supplemented with perennial ryegrass and white clover baleage. They evaluated dairy cow welfare as affected by weather and paddock conditions during a 32-day outdoor period in winter. The cows were assessed for behaviours such as lying, eating, and ruminating, as related to welfare.
Their results showed that lying time decreased on the day of rainfall and the day after rainfall with some individuals reducing their lying time by more than 40% on the day of rainfall. This was related to a lack of a comfortable lying surface, leading to prolonged lying deprivation.
Some cows were more affected by heavy rainfall periods; a third of cows did not lie down for an entire 24-hour period. Following the wet weather events, surface water pooling was high (over 80% of sites), and thus available drier space to lie down was diminished considerably (e.g., less than 4 m2 per cow). Two days after rainfall, lying time increased rebounding to about 1 h longer than before the rainfall event. Prolonged periods of standing were attributed to the observed compensatory (or ‘rebound’) lying behaviour.
Lying time also decreased with lower ambient temperature. This may relate to thermoregulation in which heat loss may be more rapid in colder temperatures when underfoot conditions are wet.
“Neither rainfall nor ambient temperature visibly affected eating and ruminating time, which further supports that lying time in this study was most likely affected by the condition of the lying surface,” the researchers concluded.
The lying surface deteriorated during and after rainfall, resulting in a wetter surface that cows were less likely to lie down on. Lying time decreased with the increasing percentage of surface water pooling, especially for cows in fodder beet paddocks. The number of lying bouts decreased with increasing mud depth, and for cows in fodder beet paddocks, the number of lying bouts also decreased with increasing percentage of surface water pooling.
For cows in kale paddocks, lying bout duration increased as the paddock became less dry, which was related to cow preference to remain lying once they had chosen to do so, perhaps because other lying areas were less desirable if they were to leave the current lying area. Alternatively, poor lying surface conditions during and after rainfall may physically limit the cow from transitioning from lying to standing or be energetically costly (e.g., due to mud depth).
It was highlighted that winter crops have different root structures that could affect soil stability and thus lying surface quality. “In this study, we were unable to examine if fodder beet and kale crops differentially affected lying time due to the limited sample size, but this deserves future work,” said the research team.
Daily rainfall did not appear to affect daily eating or ruminating time, except during the wettest study day (day 17). The percentage of sites with surface water pooling emerged as the most important paddock condition that affected lying time, so the researchers focused on this variable to determine if it also affected other behaviours.
Eating time did not appear to decrease when surface water pooling increased, except when pooling reached over 80% of sites on the wettest study day (day 17). Ruminating time appeared to decrease by about 1 hour on days when surface water pooling increased.
Researchers of the study identified the main areas of management to focus on, being type of crops in paddocks, stocking densities, daily behavioural observation of cows, soil condition and shelter.
In line with that, Karen Johnson, Extension educator at the University of Minnesota Extension emphasised: “Cows naturally adjust their metabolic rate to produce more heat to help maintain their core body temperature. Consider sorting out thin cows or heifers to provide them more specialised care such as a higher energy ration and less crowded, draft-free shelter.”
Other researchers advised against frostbite and frozen teats: “It is important that teats are dry when leaving the parlour during cold weather. It is advised to post-dip the teats and allow 30 seconds of contact time before wiping them dry. Use germicidal dips that contain 5-12% multi-skin conditioners to reduce chapping or cracking of teat skin and avoid washing teats with water in cold weather.”