1. Nutrient Requirements of Beef Cattle

2. Theorem of the 7 P’s Prior Proper Preparation Prevents Poor Production
Performance
The key to meeting any animal’s nutrient requirements is through proper nutrition. To make sure that we meet our cow’s nutrition needs we should subscribe to the theorm of the 7 P’s. It is that prior, proper preparation prevents poor productive performance. If we adopt the mindset of thinking ahead and planning for our cattle’s nutritional needs, then we should see better performance from our cows and a little heavier pocketbook.

3. The Beef Cow’s Assignment
Our expectation of a productive cow
Maintain her body weight / condition
Deliver a live calf without difficulty
Come into heat promptly
Conceive early in the breeding season
Nourish a developing fetus
Adequately nurse the calf through to weaning
So like any employee on a beef cattle enterprise our cows have a job and certain responsibilities to fulfill if she wants to stick around. Our expectations of our bovine employees are to maintain herself, deliver a live calf, start the re-breeding process promptly, get pregnant, maintain her pregnancy, and nurse the calf that is already on her side until weaning. That’s quite a load of tasks for one cow to accomplish. In order to adequately perform her duties we need to give the cow the tools and resources to do her job. The main tool for her to accomplish her assignment is adequate nutrition.

4. Nutritional Equation:
The Basic, Complicated
Nutritional Equation:
Cow Nutrient Requirements -
Nutrients Supplied by Forage =
Nutrients Needed in Supplement
So let’s address the nutritional equation. On the surface it is fairly simplistic, if we know what the cow’s nutrient requirements are and we know what the amount of nutrients that the base forage is supplying then we will know if the is a need for supplementation, and if so to what extent is the need for supplemental nutrients. The equation is complicated by the fact that cow nutrient requirements change depending upon a number of factors and further complicated by a forage base that is not static and has daily and seasonal changes.

5. Defining the Situation
What is the overall objective of the feeding / supplementation program
Extend the forage base
Meet nutritional deficiencies
Alter cow production
You have to know where you want to go before you can get there.
So when we are talking about a feeding or supplementation program we have to outline some goals. We can not effectively and efficiently feed cattle if we go not have some specific goals in mind. We don’t decide to supplement cattle just because we like to put feed in front of animals. Raisin cattle can be expensive enough, we need to use our dollars and our feedstuffs wisely. So what is the overall objective of the feeding/supplementation program? Do we need to extend the forage base through the use of supplements to get another month out of our forage resources. Are there specific nutritional deficiencies that we are aware that need to be met? Or do we want to alter animal production, having that cow make more milk, putting body weight and condition back on the cow? Ultimately, we have to set a goal of what we want to accomplish through a feeding program before we can start one.

6. Basic Required Nutrients
Water Protein Minerals Vitamins Fats Energy
There are six basic nutrients that cattle or any animal needs. Those nutrients are water, protein, minerals, vitamins, fats, and carbohydrates to generate energy. The subsequent slides briefly discuss all of the nutrients.

7. Water Water is the most critical nutrient in ALL livestock production:
Clean
Fresh
Microorganisms
Chemicals
To ensure availability and control contamination of waterways, it is best to provide cattle with water derived from a well.
Water is the most critical nutrient of all. Without water nothing else happens in the body. Digestion doesn’t occur, absorption of nutrient doesn’t happen, blood doesn’t flow, nothing. Cattle’s water needs to be clean and fresh. If you look at the water and decide that you wouldn’t drink it then consider why do you make cattle drink it. We should consider having our water source tested on a semi-routine basis to check for the incidence of contamination by harmful microorganisms and or chemicals, additionally checking water levels for mineral and heavy metal contamination could be beneficial. To ensure availability and control potential contamination of surface water sources, well derived water is a the best option. Additionally, environmental issues may necessitate the restriction of cattle from surface water.

8. Energy Energy is derived from digestion of feedstuffs
Fiber
Protein
Starch
Fat
TDN is our common measure of feedstuff energy
Net energy assigns the proportion of that feedstuff which meets
Maintenance, growth, lactation, gestation
Common sources of energy include:
forage (hay) citrus pulp
molasses grain byproducts
fat
Energy while not technically a nutrient, is one of the most important things that cattle require. Cattle generate energy from the digestion of feedstuffs. Energy is derived from the digestion of dietary carbohydrates including fiber and starch, dietary and microbial protein, and dietary fat. We measure energy content of feeds and talk about energy requirements of cattle in terms of TDN (total digestible nutrients). More advance energy discussion relate the energy content of feeds and the energy requirements of cattle in the Net energy system. The NE system assigns a proportion of the energy in the feedstuff to meet the cow’s requirement for maintenance, growth, lactation, and gestation. Common sources of energy include: forage or hay, citrus pulp, molasses, grain by-products, and fat.

9. Energy
Energy (TDN)
Major “nutrient” required by cattle
Main driver for production
Growth
Reproduction
Lactation
Direct relationship between TDN and quality of feedstuff
Low quality feed = low energy and low intake
Feed
% TDN
Bahiagrass Hay 51
Alfalfa Pellet 59
Soybean Hulls 70
Molasses 72
Soybean Meal 84
Corn 88
Energy is the major “nutrient” required by cattle. Energy is the main driver of all of the productive process in cattle, growth, reproduction, and lactation. There is a direct relationship between TDN and the quality of the feedstuff. The lower the quality of the feed, the lower the energy content of the feed, and generally, the lower the intake of the feed will be. Low quality feeds have a lot of “filler” that takes up space in the rumen, is not digested and thus provides no energy for the animal. In this table are some examples of feedstuffs and there approximate TDN value.

10. Energy Supplementation
Main driver of BCS
Reasons for use:
Reduce forage consumption
Meet energy demands
Diet selection allows
So let’s touch on energy supplementation. As was stated earlier, energy is the main driver for a lot of the productive measures in the cow herd, and body condition score is a prime example. Body condition score is measure of the relative fat content of the animal. Fat is deposited when there is an excess of energy, thus BCS is a reflection on the energy status of the animal. Likewsie, the reason for energy supplementation might include the need to reduce forage consumption to stretch a limited forage supply, the need for additional or supplementation energy to meet a deficiency of energy, or finally if there a limited amount of high-quality forage that an energy supplement could compliment.

11. Energy Supplementation Considerations
Begin feeding before it is too late
Response improves with long term low level supplementation
Feeding low levels of energy (w/out adequate diet protein) decreases overall energy intake
High starch supp. decreases fiber digestibility (Negative Associative Effects)
These are some considerations to keep in mind when formulating and implementing an energy supplementation program. First of all begin feeding energy or any supplement for that matter before is too late. Because a the response to energy supplementation improves with long-term low levels of feeding compared to short-duration high levels of energy supplementation. If you have to pour a lot of feed to forage-fed cattle to get them to respond and reach the level of production that is desirable then likely supplementation should have been initiated earlier. Additionally, while energy supplementation may be what is needed, if the protein content of the diet is not sufficient then the energy will actually have a negative effect on the overall diet energy supply. Finally, high starch supplements (corn) will have a negative impact on fiber digestions, which leads to a decrease in forage intake, and ultimately a decrease in animal performance. We call this negative associative effects, they are bad, and we want to avoid them. But generally, in Florida we do not utilize starch base energy supplements very often.

12. Protein Ruminant protein requirements are met by:
Diet
Rumen microbes
Recycling of urea
Ruminants are able to utilize “microbial- protein”, derived from microbes, which live in the rumen.
Common protein sources include:
Forage, Oilseed Meals, Grain By-products, Feather Meal
The protein requirements of beef cattle are met by three different sources. The first source is the diet, protein is derived from digestion of the forage that is consumed and any supplemental feeds that are offered. The next protein source is the digestion of the rumen microbes that grow in the rumen and then are passed to the lower GI tract for digestion. Microbial protein is the main source of protein for most grazing cattle. This protein is high quality and allows ruminants to flourish on high-forage diets. The final source of protein is actually the recycling of urea back into the rumen for the rumen microbes to utilize. Recycling of N is again and adaptation that allows cattle to consume low-quality forages and yet survive and grow.
Common protein sources include forage, which is the primary source of protein and nitrogen for the animal and the rumen microbes. Supplemental sources included oilseeds and oilseed meals like soybean and cottonseed meal, grain by-products are sources of protein (distillers grains, corn gluten feed), finally approved animal by products like feather meal, fish meal, and porcine blood meal.
John Arthint5)

13. Natural Protein Considerations
Utilization: similar among classes of animals
Use with younger animals with increased requirements
Fed as dry or additive in liquid feeds
Supplies N to rumen for microbes and protein to animal
When we consider the supplementation of natural protein the utilization of natural protein is similar among different classes of cattle. I would suggest that younger cattle make the best use of natural proteins compared to older cattle. The improvement in younger cattle is because younger cattle have maintenance and growth requirements. The growth requirements require amino acids which natural protein with bypass characteristics can supply.
Natural proteins can be utilized either as dry supplements in meal or pellets or incorporated into liquid feeds to create slurries. Finally, the use of natural protein supplies both nitrogen and protein to the rumen microbes for their metabolism, and also amino acids and peptides for the animal itself.

14. Non-Protein Nitrogen
Synthetic (Urea, Biuret) chemical compounds that contain a nitrogen source not associated with protein.
Improvement in performance compared with no supplementation.
Utilization rate may be reduced because of decreased forage digestibility potential.
Lacks energy, vitamins, and minerals.
Urea is a common NPN source used in cattle supplements.
Rumen microbes are able to use NPN to synthesis microbial protein.
Feed Non-protein-nitrogen is are compounds, generally urea, that contains nitrogen attached to a carbon back-bone. Thus all NPN supplies is N only. When feeding NPN sources cattle performance improves compared to no supplemental nitrogen. NPN has some limitations, the utilization rate of urea may be decreased if the digestion potential and the resulting energy supplied by the forage is limiting. Additionally, urea does not supply any additional energy, vitamins, or minerals as a supplement. However, despite these stated limitations, urea is a common NPN source that is often included in many cattle supplements. The reason that urea works is that the rumen microbes can utilize the nitrogen provided by NPN sources, match it with energy substrates from fiber digestion to form microbial protein. The animal then utilizes the microbial protein as a protein source.

15. NPN Considerations Management Issues Potentials for toxicity
Mature cows consuming forage of adequate quality can use NPN as an economic substitute to natural protein.
Better performance in older cows than young/growing cows.
Young and low body condition cattle will experience improved performance with the use of natural protein.
Potentials for toxicity
Requires a carrier that supplies energy
Success of utilization depends on adequate ruminal energy for microbes
Liquid Feeds (Molasses)
Provide carbohydrates for bacterial energy to utilize NPN.
Some consideration for the use of NPN in supplementation programs. Mature cows consuming adequate amounts of digestible forage can utilize NPN as an economic source of nitrogen to support microbial protein production. Generally, we would expect better performance of mature cattle compared to younger cattle when utilizing NPN. This is related to two factors: first, that mature cows can consume more digestible forage than younger cattle and thus have a greater amount of fermentable fiber and thus energy to match the N in the rumen; secondly, young cattle still have growth requirements that require amino acids, vitamins, minerals, and additional energy that NPN does not provide. There is the potential for toxicity when using NPN sources, however, I believe that this threat is often overstated and wrongfully perpetuated. Most problems associated with urea toxicity occur with bad formulations of poorly manufactured supplements and/or the use of high urea supplements as the major source of nutrition rather than as a supplement to a forage diet. Urea (NPN) requires a carrier to deliver the product, often this carrier provides the energy to couple with the N in the rumen. Therefore, the success in utilizing urea is having adequate ruminal energy supply for the microbes. In Florida we have a great carrier for NPN in liquid molasses. Molasses provided the carbohydrate substrate to create energy for the rumen microbes, molasses acts as a great carrier, and comes with some amount of additional nutrients.

16. Vitamin-Mineral Supplementation
Vitamin-Mineral deficiencies cause problems regardless of protein/energy
Deficiencies in forage
especially low quality
fast-growing and/or winter annuals
Other supplements may alter mineral availability in forage
Efficacy of all other supplementation depends on vitamin/mineral adequacy
Meeting vitamins and minerals requirement are just as important to beef cattle production as meeting energy and protein requirements. That is because a deficiency in a vitamin or mineral will cause a loss in performance regardless of the amount of energy or protein content of the diet. In many cases our forage base may be deficient in one or more vitamins or minerals. These deficiencies may be particularly apparent in low quality/mature forages or fast-growing /winter annual forages. The interaction of all of the feedstuffs in the diet may alter the availability of vitamins and particularly minerals. Excess concentrations of certain minerals can have negative effects on the availability of other key minerals in the diet. Finally, the efficacy of the nutritional program is dependant on adequate vitamin/mineral status of the animal.

17. Mineral Supplementation
Forage most important contributor
Macro-minerals
> 1 gram/day
Micro-minerals
< 1 gram/day
Essential for basic physiological processes
Many forage sources are deficient in multiple minerals
Macro
Micro
Potassium
Copper
Magnesium
Iron
Sodium
Manganese
Sulfur
Zinc
Phosphorus
Cobalt
Calcium
Iodine
Selenium
The forage base, pasture or hay, is the most important contributor of minerals for cattle just like it is for energy and protein. However, because of differences in forage type and quality the forage base also causes some of the major dietary deficiencies. There are two types of mineral classifications, Macro and Micro. Macro minerals are those minerals required in the diet in greater than 1 gram amounts, whereas micro minerals are those that are required in less than 1 gram amounts on a daily basis. In the table on the right are some of the important macro and micro minerals that need to be addressed when formulating mineral supplements to meet cattle nutrient requirements. The need for minerals is paramount because they are essential for many of the basis physiological process in the body (regulation of osmotic pressure, transmission of nervous impulses, antioxidants, bone growth, etc.). Generally, our forages are not just deficient in one mineral, thus mineral supplements to meet cattle requirements should be well-balanced to address all of the potential mineral concentration shortfalls in the forage.

18. Vitamin Supplementation
Water-soluble
Fat-soluble
Ruminants synthesize water soluble vitamins
Fat-soluble vitamins often supplemented
Vitamin A
Low quality, hay, or frosted forage when consumed for >2 months
Water
Fat
Thiamine (B1)
Vit. A
Riboflavin (B2)
Vit. D
Niacin
Vit. E
Biotin
Vit. K B6
B12
Pantothenic
Acid
Folic Acid
Like minerals, vitamins are separated into two different classes, water soluble and fat soluble vitamins. The table on the right breaks down the vitamins according to their solubility. Ruminants do not normally need to be supplemented with B vitamins or any of the other water soluble vitamins to meet their nutritional requirements. The rumen microorganisms synthesize adequate levels of all of the B vitamins, niacin, pantothenic acid, and folic acid to satisfy cattle requirements. The fat soluble vitamins with the exception of vitamin K are often incorporated into well-formulated good quality vitamin/mineral supplements. Fat soluble vitamins can be stored in specific tissues of the body for limited time periods, but cattle benefit by having adequate levels of fat soluble vitamins supplemented to their diet.

19. What affects cow nutrient requirements
Nutrient requirements differ:
Age
Level of production
Current and/or desired body condition
Breed
Physiology
Lactation
Gestation
Pasture activity
Terrain
Pest load
Feed Additives
Ionophore
Environment
Temperature
Season
We’ve outlined the different nutrients that are needed by cattle, including water, protein, energy, vitamins, and minerals. The amounts of these nutrients that are required by cattle are affected by an number of different factors. The nutrient requirements differ for different ages, level of production, breed, and stage of physiology of cattle. Additionally, there is a whole list of other factors that can affect the level of nutrients required by cattle.

20. Comparison of Cow vs Heifer Energy Requirement
The previous graph did not demonstrate a great difference between cow and heifer energy or protein requirements. However, the difference in nutrient requirements and feeding management between these two ages of cattle is readily apparent. This set of graph is a comparison of a 1200 lb cow and a 1000 lb heifer with a mature body weight of 1200 lb. On the left is the estimated dry matter intake of these two animals assuming a intake potential of 2.0% of BW. In that case a mature cow can consume 24 lbs of dry matter compared to 20 lbs by the heifer. On the right is the %TDN required in the diet one month prior to calving. The mature cow with her greater intake potential requires a diet that is 56% TDN compared with the heifer that requires a diet TDN of 60%. The heifer can not consume as much feed, but her total lb of TDN required is still similar to that of the cow, thus her diet needs to me more energy dense compared to the cow. This principle would similar for protein requirements.

21. How to tell if cattle are getting adequate nutrition
Body Condition Score
Estimation of body fat
Gauge effectiveness of feeding program
Decision tool to determine future feeding needs
Scale of 1 to 9
Most cows score from 3 to 7
BCS 3 = 7 to 9% fat.
BCS 5 = 15 to 18% fat.
BCS 7 = 25 to 27% fat.
The best way to asses the effectiveness and adequacy of a nutritional management program is to body condition score the cow herd. Body condition scoring is an estimation of the amount of body fat a cow has. Fat requires there to be a surplus of energy before it is deposited, therefore the amount of fat cover on cows is a good indicator of their energy status. Body condition scoring can be utilized as a decision making tool for future feeding needs, it can indicate either additional feed is required or a decrease in the energy supplied could be realized. Body condition score is ranked on a scale of 1 which is severely emaciated to 9 which is severely obese. Most cows fall in the range of 3 to 7.

22. Cow Body Condition Score
Body condition score is the best measure of past nutritional status and a good indicator of future reproductive performance.
5 is the magic number!
Body condition score is an indicator to the past energy status and coupled with current feeding situation can be utilized to determine the appropriate feeding program. Body condition score is also a good indicator of future reproductive performance. Reproduction responds positively to adequate body condition score. A body condition score of 5 is the magic number. A BCS of 5 has been shown to optimize reproductive performance in terms of the return to estrus, days to conception, calving interval, pregnancy rate, and weaning percentage.

23. Supplementation
Feeding the cow herd is the largest cost area in beef enterprises, approx 45-50% of annual maintenance cost
Stored or supplemental feeds constitute the largest, most variable portion
Designing supplementation program correctly is a must
Why are we so concerned about meeting nutrient requirements and their relationship to supplementation? Feeding the cow herd represents the largest single cost in beef enterprises approximating 45-50% of the annual maintenance cost of keeping a cow. In that regard the use and of stored or supplemental feeds is the largest and most variable portion of that cost. Therefore, correctly designing a supplementation program to meet nutritional deficiencies and optimize cow herd performance is critical to the overall profitability of the beef cattle enterprise.