A dairy cow’s #1 job is to produce milk, and she needs a lot of water to do that. But two studies recently published in the Journal of Dairy Science show that water access and consumption is not an equal-opportunity proposition for cows.
The first study, conducted at the National Research Institute for Agriculture, Food, and the Environment in France, looked at cow behavior and water consumption based on access to an abundant number of waterers versus a more limited number.
The second, conducted by researchers in the Animal Welfare Program at the University of British Columbia, examined social dominance behaviors related to water consumption and compared behaviors based on different environmental conditions.
Both studies were conducted in free stall housing settings, and employed electronic waters and various electronic monitoring devices to measure individual-cow intake, number of visits, and timing of visits to water sources.
In the French study, 40 cows were evaluated during the final 5 days of two different drinker densities. In the first installment, access was allowed to 12 waterers. That number was cut by two-thirds to just 4 waterers in the second evaluation period. The 4 waterers were in compliance with current welfare standards in France, which dictate that 10% of a herd’s cows be able to drink at the same time. [U.S. recommendations are similar].
The French researchers found that access to fewer waterers significantly increased competition for water. Cows pushed each other out of the way more frequently, and subordinate cows drank faster and made more visits to the waterer to satisfy their drinking needs, compared to more dominant animals.
Dominant cows monopolized waterers and drank 5 L more per day compared to the less dominant groups. Mid-subordinate cows achieved their water intake needs by shifting their drinking times to avoid peak drinking periods. The researchers noted that this adaptive behavior indicates a poorer animal welfare outcome for those animals, because they were unable to satisfy their motivated drinking behavior during peak consumption times.
The British Columbia study evaluated data from 87 cows (housed in groups of no more than 48 each) over 112 days.
In it, a hierarchy among cows regarding water access and use was also distinctly observed. In fact, they found it to be steeper (more pronounced) than the social hierarchy related to feed consumption. But it was definitely correlated between both groups, identifying the same cows as more dominant versus submissive.
They also evaluated drinking behaviors in normal environmental conditions -- with a temperature-humidity index (THI) of 72 or less – and compared them to heat-stress conditions in which the THI was above 72. No significant difference was found between the two environments, and the same social dominance patterns were consistent at both levels of THI.
Among those behaviors, the most dominant cows made fewer visits to waterers, had higher water intakes, and accessed the waterers more frequently during peak competition times immediately after milking.
The British Columbian researchers noted that, while not evaluated in their study, previous research has shown that more dominant animals in dairy herds tend to be larger, older, and higher milk producers.
This was confirmed by the French study, in which first-calf heifers were mixed with multiparous cows. The subordinate cows were found to be 70% first-calf heifers, and only 20% of the dominant cows were first-calf heifers. Subordinate cows also weighed significantly less than their dominant herd mates.
While both teams indicated the need for additional research to delve further into the details of drinking behaviors – in terms of both animal performance and welfare -- some general recommendations that can be drawn from their work include:
- If possible, stratifying social groups according to parity and/or body size could help minimize displacement of cows due to social hierarchy.
- Demand for water is highest immediately after milking. Particularly during new construction, consider placing waterers to allow easy access based on return patterns from the milking area.
- Greater access to more waterers is better. The French researchers noted that the “10% of herd” standard was based on research conducted several decades ago, when cows produced much less milk. They concluded the standard “may not be appropriate for today’s farms from an animal welfare point of view.”
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