Saying “water” is not enough

Water is definitely the most important component of diet for dairy cows. The National Resource Council (2001) defines it “the essential nutrient for the health and performance of a dairy cattle”. Water is ubiquitous inside the body and intervenes in several processes:
  • digestion;
  • nutrient’s absorption;
  • transport of metabolites and hormones;
  • lubrication and support for several organs and the fetus;
  • sweating and milk production;
  • elimination of faeces and urine.
The water balance depends on the amount of water introduced and from that lost with feces, urine, milk (87.5% of a liter of milk is water), sweating and evaporation through the respiratory organs. The reduction of 10% of body hydration level causes breakdown and decrease in production; 20% is even fatal. The quantity of lost water depend on the quantity of milk produced, temperature and environment humidity, animal’s physical activity, respiratory rate and diets factors.
Water requirement
Daily water requirement of a milking cow is esteemed to be 5 lt per kg of dry matter ingested and it is satisfied essentially by two sources:
  • water ingested directly;
  • water contained as humidity in food ration.
Naturally this amount, that in normal conditions is around 100 litres/head/day, varies according to the type of ration, ingestion, production and above all according to environmental conditions. It has been calculated that the water requirement can grow of 30% at 20°C, 50% at 25°C and double at 30°C.
Drinking behaviours
The major quantitative of water is taken soon after milking. Therefore, it is an excellent strategy to provide a well-dimensioned point of water intake along the returning path toward the barn. Observing the behaviour of cows you can notice that, if there is the possibility, they alternate water and food intake. Normally, a cow drinks about 8-10 times a day, ingesting 10 litres of water every time in about 30 seconds.
Watering place
“…it won’t be deemed compliant the administration of split water or the presence of even only single subject bred in absence of water administered ad libitum, since all the cows in the farm have to be allowed to satisfy their own water needs drinking when and how much they want…” (CReNBA) Based on this principle, it is crucial to think precisely about the dimensioning and positioning of watering places in the barn. As indicated, 10 cm of watering place for each cow present are considered enough, placed at a height of about 70-80 cm from the ground. The capacity of the watering place must guarantee the presence of about 7-8 cm of water, so that cows can drink dipping the mouth without inhaling air. Concerning the placement, is fundamental the presence of at least 2 watering places per group, better within 15 m from the feeding area. In the case in which the watering place is placed in a passage, the width of this one should be about 5 m, so that the presence of cows drinking doesn’t debar the movement of other animals (Picture 1). Moreover, you have to evaluate the shading of drinking places, above all in anticipation of the warmest moments of the year: if cows have to choose between staying in the dark and walk to a watering place in the sun, they will always choose the dark, inevitably reducing their water consumption.
Picture 1 - Optimal width for a passage where water places are put
Water quality
The quality of water is a matter of extreme importance. There are 5 criteria to evaluate:
  • organoleptic properties;
  • physic-chemical characteristics;
  • excess substances;
  • toxic substances;
  • microorganism.
Organoleptic characteristics, such as smell and taste, can be easily detected from animals and in case of unpleasant smells or tastes, ingestion can be highly affected. Physic-chemical characteristics such as PH and hardness usually do not present risks for the health, while the excess of some components such as Iron, Sodium, Sulphates and Fluorine could give some problems and / or deject ingestion. The presence of toxic substances is, except in exceptional cases, below the alert levels. On the other hand for the count of microorganisms, there may be a concrete biological risk. For all these reasons, it should be desirable to make periodic analysis of water so that you can be sure that drinking water lacks of unpleasant smells and tastes, toxic substances and contaminants that can be dangerous for the animals’ health or that can affect directly or indirectly on the sanitary quality of food. Together with the execution of regular analysis, the creation of a periodic cleaning protocol of watering places allows to check constantly the correct running and to offer the animals clean water, clear, without food waste, algae or manure, optimizing hygiene and maximizing water consumption by cows. (Picture 2)
Picture 2 – Relying on how water appear in watering place, would you be willing to drink from it? If the answer is no, then water is not enough clean neither for your cows! (BEEDE, 1992)
Water temperature
After evaluating all the aspects written until now, it is worth to linger on the temperature of the water administered to our animals. As already said, water consumption is directly proportional to the consumption of dry matter. But it has been observed that this relation can be modified by the administration of too cold water, which alters momentarily rumen temperature. Various studies report positive effects of the administration of heated water, especially during winter season. The ingestion of too cold water diminish rumen temperature (Petersen et al., 2016) altering fermentations and microbial activity (Hungate, 1966), above all regarding fibre digestion, which takes place at an optimal temperature of about 38°C (Roger et al., 1990). Petersen et al. (2016), in a study that has been conducted for 3 years, have found that cows with access to heated water drank 30% more, than groups of animals, which didn’t have access to heated water. For this reason, mainly in the coldest months, the employment of tools which allow to maintain water temperature at about 18-20°C in watering places, permit to maximize ingestion, without altering rumen balance. Another advantage can be obtained, since they avoid the pipes to freeze, and so the missed water supply to the herd.
Nowadays people do not give enough attention to water inside the complex world of dairy cows’ feeding. Water should be considered a main component of the ration and treated like that. Periodical analysis, constant cleaning protocols of watering places and check on a correct administration regarding quantity and temperature, are aspects that have to be integrated necessarily in the daily routine of a dairy farm.