August 2017

We often focus on forage quality and supplemental products to manage our production rates or animal health when considering beef cattle nutrition. This inherently causes us to lose sight of the most important nutrient that beef cattle need – water. The most attention this nutrient receives in most publications is an off-hand acknowledgement of the animal’s need for continuous supply of fresh clean water. I thought that a more in-depth look at water requirements and quality parameters for beef cattle would be a good idea, especially given that we Carolinians are currently in the throes of heat, humidity, and other environmental stressors of the Mid-Atlantic summer.

Water makes up 50-80% of a beef animal’s weight and is involved in virtually every cellular function of the animal’s biology. It’s easily understood that any deficiency in amount or quality of water can have tremendous effects the animal’s ability to produce as it is expected to. University of Nebraska-Lincoln publications recommend that beef cattle need about 1 gallon of water for every 100 pounds of body weight, given average production conditions. That means an average 1200-pound adult beef cow requires 12 gallons of water a day. During the production year, however, a beef cow will experience many different challenges that affect her water intake. Factors such as lactation, heat stress, forage growth, salt intake, etc. can either increase or decrease her water needs on any given day. Lactation can increase a beef cow’s daily water intake by 5-10 gallons compared to the intake of a dry cow. Heat stress in Southeastern cattle is likely the biggest driver of increased water consumption. A University of Georgia publication estimates that a cow-calf pair experiencing a daily high temperature of 90 degrees doubles their drinking water requirements. That’s 2 gallons of water per hundred pounds of body weight daily meaning that same average cow from before would need somewhere on the order of 25-30 gallons of water per day!

Water requirements can be met via several different routes. First and foremost, cattle should have free access to drinking water at all times. The source of that drinking water can be highly variable across operations. Most producers I work with either supply drinking water through providing cattle access to ponds, streams, spring-fed tanks, or drilled wells. During peak forage growth, a cow may consume up to 75% of her daily water needs through grazing, as fresh growing grass is mostly water. Un-weaned young stock meet most of their daily water needs through nursing. Since water intake can take place through different routes, it can be difficult to quantify accurately. Therefore, it is important to ensure there is adequate drinking water available at all times for the number of head and stage of production your animals are in. Factors to consider are: number of drinkers in pasture/pen, flow rate of well, consumption dynamics of animals, temperatures and rainfall (for ponds), and diet.

Under deprivation conditions, cattle have a limited capacity for conserving water. Conservation is accomplished primarily through the animal’s kidneys where urine will be concentrated before being excreted. This level of water conserved is limited, and will certainly not make up for deficiencies in water intake for a prolonged time-period. Animals are less able to conserve water if diets are high in sodium or protein as urine (and water) excretion rates increase. Conditions such as dehydration and salt toxicity are directly life threatening to cattle facing water deprivation. More insidiously, mild dehydration can lead the animal to be less resilient in the face of other stressors such as parasitism, poor nutrition, or heat stress.

It is not enough to ensure animals get adequate quantities of water; it is also important to ensure animals have access to good quality water. Here are some quality parameters to consider:

• Dissolved solids: Also known as Total Dissolved Solids, TDS. This general quality datapoint measures any minerals, salts, metals, or small organic compounds dissolved in water. The lab measures the sum of positively charged ions and negatively charged ions, such as calcium, magnesium, potassium, sodium, bicarbonates, chlorides, and sulfates, to generate the number on the test report. High levels of dissolved solids can be found in both well water and pond water, and can result in animals having poor performance. For all classes of cattle, use of a water source should be discontinued if TDS is higher than 5000 ppm. TDS less than 3000 ppm is considered “good” drinking water, and should not contribute to any health problems in the cattle consuming it. Results in the “gray zone” between 3000 and 5000 ppm can lead to production and/or health problems, especially if compounded with other stressors.
• Nitrates: Nitrates come from manure or fertilizer contamination of drinking water sources. We often think of nitrates as a problem of hay or forage, but water can also be a major source of these toxic compounds. Chronic exposure can lead to decreased weight gains or milk production, susceptibility to other illnesses, and abortions in pregnant cattle. Acute toxicity from ingesting large quantities of nitrate can cause sudden death, with young animals being far more suspectible. Surface water sources of drinking water tend to be more problematic as they can collect runoff from agricultural land or concentrated animal holding areas. Water containing 300 ppm or more is considered unsafe for livestock to drink and less than 100 ppm is considered safe. When levels are between 100 and 300 ppm, safety is considered “questionable” and your veterinarian should be contacted to discuss particular issues with your current herd. It is important to remember that nitrate intake problems can be additive and that both water and forage sources should be tested regularly to ensure no losses in production or life occur. Drought conditions can concentrate nitrates in both drinking water and forage sources, and should be closely monitored at those times.
• Mineral content: Somewhat separate from total dissolved solids are minerals such as sulfur, manganese, and iron. These minerals can cause rejection of drinking water by animals due to foul flavors or odors. If animals do consume the water, the high levels of certain minerals can interfere with the animal’s ability to absorb other important minerals in their diet such as zinc, copper, and magnesium. This is problematic in that these minerals are important for immune function, reproduction, and muscle growth, thus limiting health and production performance.
• Temperature: Believe it or not, even the temperature of water consumed can affect intake and performance. Cold water helps cattle maintain normal body temperature in the summer and encourages water consumption. Shallow ponds and small water tanks heat up and this warm water causes cattle to decrease their intakes. Deep ponds or groundwater pumped into large tanks do not heat up to the same degree, and promote better water consumption.
• Algae: Blue-green algae is a major issue for ponds that have high nutrient loads. Under certain conditions, the algae produces toxins that are deadly for cattle consuming the water. This is most likely to happen in the summer or early fall when cattle consume large amounts of water right after a major algae bloom. Best management practices to prevent losses from blue-green algae are to aerate the pond, prevent nutrients from entering the pond, or fence cattle out of pond and pipe water to a trough. The intake pipe needs to be at least three feet below the surface to prevent toxins from making it into the trough.

Water is the most important nutrient for cattle. Inadequate provision of fresh, clean water is one of the most common nutritional problems dealt with on cattle operations. Regardless of source of drinking water, amount and quality of water provided needs to be monitored closely throughout the year to ensure no limitations are being unnecessarily placed on our animals’ production or health. There are pros and cons to different water sources, but the bottom line is cattle need the best quality water possible and investments made in providing that will be rewarded through healthier, more productive animals. The only way to know if your water source is good, bad, or ugly is to test for anti-quality factors. Contacting your local livestock veterinarian or county Extension agent is the best way to get sampling and submission information. Once you have test results back, it is vitally important to work with your herd veterinarian to interpret the test results and act proactively based on the data collected.