K-State Research and Extension

“Got Water…But How Much Do Those Cows Need?”

Justin Waggoner, Ph.D., Beef Systems Specialist

Most cattle producers fully understand the importance of water. After all, providing an adequate supply of clean, fresh water is the cornerstone of animal husbandry and there are very few things that compare to the feeling of finding thirsty cows grouped around a dry tank on a hot day. Water is important, and in situations where the water supply is limited or we are forced to haul water, one of the first questions we find ourselves asking is “how much water do those cows need?” The old rule of thumb is that cattle should consume 1‐2 gallons of water per 100 lbs of bodyweight. Accurately determining the amount of water cows will voluntarily consume is difficult and is influenced by several factors (ambient temperature, moisture and salt content of the diet, body weight, lactation, etc.). Water consumption increases linearly as ambient temperature increases above 40  Fahrenheit such that cows require an additional gallon of water for every 10 degree increase in temperature. Additionally, lactation also directly increases the amount of water required by beef cows. The table below summarizes the daily water requirements of beef cows of several different body weights, milk production levels, and ambient temperatures.

“What’s Your Cost of Production?”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

I can assure you that Henry Ford knew exactly how long and how much it cost to produce the Model T. Although it may seem difficult to make comparisons between the automotive industry and modern day beef production, many cow‐calf operations are business enterprises…large business enterprises. Yet financial benchmarking and accurately documenting production costs are not necessarily high on the “to do” list of most cattle producers. One of the best reasons to know what it costs to produce a calf or what your total feed and non‐ feed costs are is that it allows you to quickly evaluate emerging opportunities such as grazing a neighbor’s cover crop or an additional circle of corn stalks. Thus, if you don’t know your production costs, I would encourage you to think about them. Tax time is a great time to take a good look at your business and calculate your production costs. If you would like to get a better idea of what it costs to produce a calf in Kansas, the Kansas Farm Management Association (KFMA) Enterprise Reports provide that information in a one page summary that can be accessed on the Ag Manager website (https://www.agmanager.info/kfma). The chart below shows the total feed and non‐feed (operational) costs of KFMA participating cow‐calf producers from 2015 to 2019.

The data from these operations suggests that in 2019, feed costs were approximately $504 per cow and the non‐feed or operational costs were approximately $584 per cow. Thus, the average total cost to produce a calf was $1088 ($504 + $584) on these operations in 2019. The total feed costs (pasture and purchased feed) of $504 amounts to $1.38 per day to feed a cow in Kansas. The question is “What does it cost you to feed a cow and produce a calf?”

For more information, contact Justin Waggoner at jwaggon@ksu.edu.

“Mineral Nutrition”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Most beef cattle producers recognize that mineral nutrition is important. However, a mineral program is only one component of an operation’s nutrition and management plan. An exceptional mineral program will not compensate for deficiencies in energy, protein or management. Additionally, the classical signs associated with clinical deficiency of a particular mineral (wasting, hair loss, discoloration of hair coat, diarrhea, bone abnormalities, etc.) are not often or are rarely observed in production settings. The production and economic losses attributed to mineral nutrition in many situations are the result of sub‐clinical deficiencies, toxicities, and antagonisms between minerals which are often less obvious (reduced immune function, vaccine response, and sub‐optimal fertility).  The figure below, adapted from Wikse (1992), illustrates the effect of trace mineral deficiency on health and performance and the margin between adequate mineral status and clinical deficiency.

There are 17 minerals required in the diets of beef cattle. However, no requirements have been established for several minerals that are considered essential (Chlorine, Chromium, Molybdenum, and Nickel).  Minerals may be broken down into two categories. 1. The macrominerals whose requirements are expressed as a percent of the total diet (calcium, phosphorous, magnesium, potassium, sodium, chlorine and sulfur). 2. The microminerals or trace minerals (required in trace amounts) whose requirements are expressed as parts per million (ppm) or milligrams per kilogram of dry matter consumed (chromium, cobalt, copper, iodine, iron, manganese, molybdenum, nickel, selenium, and zinc).

Mineral status of an animal is a function of the total diet (both water and feed) and stored mineral reserves within the body. Water may be a substantial source of mineral; however, the variation in water consumption makes estimating the contribution of mineral from water sources difficult. Mineral content of forages is influenced by several factors including plant species, soil, maturity, and growing conditions. These factors, and others not mentioned, make estimating the dietary mineral content of grazing cattle challenging.

Most commercial mineral supplements are formulated to meet or exceed the requirements for a given stage of production. This ensures that deficiencies are unlikely, but providing supra‐optimal levels of minerals may be unnecessary unless specific production problems exist. Minerals are an important component of beef cattle nutrition that should not be over‐looked as sub‐clinical deficiencies of minerals likely contribute to more production and economic losses than we realize.

For more information, contact Justin Waggoner at jwaggon@ksu.edu.

“Body Condition Scoring: A Herd Management Tool”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Body Condition Scoring is one of the most valuable management tools at the disposal of the cattle manager. This one number gives us a direct indication of an individual cow’s previous plane of nutrition and future reproductive capability. Although the individual body condition scores are important, we don’t necessarily manage individual cows, we manage groups of cows. Thus, it is important for us to look beyond the individual scores and look at the distribution of body condition scores within the herd.  If we have a herd (Herd 1) with an average body condition score of 5 that is essentially characterized by the classic bell curve, with a few thin cows (3’s), the bulk of cows in the middle (4’s and 5’s) and few over‐conditioned cows (7’s), everything is good. Alternatively, we could have a herd (Herd 2) with an average body condition score of 5 that is essentially the result of a few thin cows (3’s) and some over conditioned cows (6’s and 7’s). Body conditioning scoring also has more value when it is done on the same group of cows at multiple times during the production year.  If Herd 2 was scored at calving and had been previously scored at weaning and had an essentially normal distribution (similar to Herd 1), we need to ask ourselves what happened. Did we change anything? Although these examples are somewhat extreme, they illustrate that we have to look beyond the individual body condition scores of cows at one point during the production year to get the most of body condition scoring.

We have several resources on body condition scoring available on the web that may be accessed at https://www.asi.k‐state.edu/research‐and‐extension/beef/feedandwater.html  including the quick reference guide to body condition scoring shown below.

For more information, contact Justin Waggoner at jwaggon@ksu.edu.

“Cold Stress in Cattle”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Most cattle producers appreciate that cold weather increases nutrient requirements. However, what increases? And by how much?

Cattle are most comfortable within the thermoneutral zone when temperatures are neither too warm nor cold. The upper and lower boundaries of the thermoneutral zone are referred to as the upper and lower critical temperature. During the winter months, cattle experience cold stress anytime the effective ambient temperature, which takes into account wind chill, humidity, etc., drops below the lower critical temperature. The lower critical temperature is influenced by both environmental and animal factors including hair coat and tissue insulation (body condition). The table below lists the estimated lower critical temperatures of cattle in good body condition with different hair coats. In wet conditions cattle can begin experiencing cold stress at 59°F, which would be a relatively mild winter day. However, if cattle have time to develop a sufficient winter coat the estimated lower critical temperature under dry conditions is 18°F.

Cold stress increases maintenance energy requirements but does not impact protein, mineral or vitamin requirements. The general rule of thumb (for a cow in good body condition, BCS = 5 or greater) is to increase the energy density of the ration by 1% for each degree (Fahrenheit) below the lower critical temperature. The classic response to cold stress in confinement situations is an increase in voluntary intake. However, it has been documented that cattle maintained in extensive environments (native range, wheat pasture, corn stalks) may spend less time grazing as temperatures decline below freezing, which reduces forage intake (Adams et al., 1986) and makes the challenge of meeting the cow’s nutrient requirements even greater. In many cases feeding a greater amount of low-quality hay will replace grazed forages but may not provide sufficient energy. Therefore, providing additional energy by feeding a higherquality hay or fiber-based supplement (DDGS, Corn gluten feed, or Soybean Hulls) may be required.

For more information, contact Justin Waggoner at jwaggon@ksu.edu.

“How Much Water Do Those Cows Need?”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Most cattle producers fully understand the importance of water. After all, providing an adequate supply of clean, fresh water is the cornerstone of animal husbandry and there are very few things that compare to the feeling of finding thirsty cows grouped around a dry tank. Water is important and, in situations where the water supply is limited or water is being hauled (i.e. grazing crop residues), one of the first questions we find ourselves asking is “how much water do those cows need”? The old rule of thumb is that cattle should consume 1-2 gallons of water per 100 lbs of bodyweight. Water consumption increases linearly as ambient temperature increases above 40° Fahrenheit such that cows require an additional gallon of water for every 10 degree increase in temperature. Additionally, lactation also directly increases the amount of water required by beef cows. The table below summarizes the daily water requirements of beef cows of several different body weights, milk production levels and ambient temperatures (Adapted from Spencer, 2016).

Spencer, C., Lalman D. Rolf, M., Richards, C. 2016, Estimating water requirements for beef cows. Kansas State University MF3303. https://www.bookstore.ksre.ksu.edu/pubs/MF3303.pdf

For more information, contact Justin Waggoner at jwaggon@ksu.edu.

“Feedlot Heifer Performance in 2019”

By: Justin Waggoner, Ph.D., Beef Systems Specialist

Each year, I summarize the data from the K-State Focus on Feedlots, in an effort to document annual trends in fed cattle performance. The Focus on Feedlots data for heifers from 2019, 2018 and 2017 is summarized in the table below. The number of heifers marketed decreased in 2019 with more than 26,900 fewer heifers being marketed in 2019 than 2018. Heifer in weights were slightly lower, averaging 704 lbs in 2019. Final weights of heifers were on average 7 lbs lower in 2019 at 1265 lbs, compared to 1272 lbs in 2018. Heifer days on feed increased to 175 days, an increase of 9 days relative to the 166 days reported in 2018. Heifer average daily gain was similar across years, but feed conversion increased relative to 2018 and 2017. Death loss increased to 2.01% relative to 1.75% and1.64% death losses reported in 2018 and 2017, respectively.

Total cost of gain increased in 2019 to $89.48/cwt. Heifer cost of gain was $5.11/cwt greater on average than that of steers, $84.37/cwt versus $89.48/cwt.

For more information, contact Justin Waggoner at jwaggon@ksu.edu.