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Questions and
Answers on
Beef Cattle Nutrition
Chris Reinhardt
Feedlot Specialist
Sandy Johnson
Livestock Production, Northwest
Joel DeRouchey
Livestock Production, Northeast
Dale Blasi
Stocker Production
Ron Hale
Livestock Production, Southwest
Larry Hollis
Beef Veterinarian
Twig Marston
Cow/Calf Production
Kansas State University
Agricultural Experiment Station and
Cooperative Extension Service
Questions and Answers on Beef Cattle Nutrition the forage analyzed for calcium and
Maintaining a profitable cattle operation is increasingly difficult. And provid- phosphorus.
ing a well balanced ration at a reasonable cost is increasingly complex. This pub- 5. How do I use a forage crude
lication provides concise answers to specific questions. Questions are divided into protein analysis?
six categories, making information easy to find: By estimating the pounds of for-
Roughages................................................................................................. page 1 age an animal is consuming each day,
Crude Protein and Urea......................................................................................4 you can use the crude protein analysis
Concentrates and Grain Processing...............................................................7 to determine if you are meeting the
Vitamins, Minerals and Water...........................................................................8 animal’s protein requirements.
Additives and Implants.....................................................................................10 Example: Requirement is 1.4 pounds
Commercial Supplements...............................................................................13 crude protein (CP)/day We estimate
an animal consumes 15 pounds of 6
The list of questions addressed in on the class of livestock, forage quality percent CP hay per day:
the roughages section tells you what can be very important. In general, as 15 x 6% = 0.9 lbs. of CP/day
kinds of information you will find: the percentage of roughage in the diet 1.4 lbs. CP required – 0.9 pounds. CP
What is forage quality? How impor- increases, the impact of forage quality from forage = 0.5 lbs./CP deficient
tant is it? What are the key factors also increases. Successfully harvest- from animal’s protein requirement.
influencing forage quality; what lab ing top quality forage can reduce the 6. How do I determine the
analyses should one get on forages? amount of protein supplement and energy level of forages?
How do you use a forage crude protein grain fed and reduce the amount of A commercial laboratory can
analysis? How do you determine the forage needed to get the same animal estimate the TDN or energy content
energy level of forages; Should you performance. (NEm, NEg) from the forage analysis
make hay or silage out of forage crops? 3. What are the key factors by using the ADF level as an indicator.
How can corn and milo crop residue influencing forage quality?
be used most economically? Can corn Stage of growth at cutting time 7. Should I make hay or silage out
or milo stover be made into silage? and proper moisture level at harvest of my forage crops?
Can wheat straw be used in beef are key factors that influence forage The decision to make hay or silage
cattle rations? Should one consider quality. Some forages such as alfalfa is an economic and management ques-
ammoniating wheat straw? Can the need to be cut when immature (early tion. As a general rule, crops harvested
producer make wheat and other small bloom). Forages such as corn and as silage will have 10 to 25 percent
grain forages into silage? What is the forage sorghum silages have more feed greater feed value than the same crops
status of harvesting high-moisture value when cut at the dough stage of cut as hay. Forage field and feed-
hay? Are silage additives necessary to grain maturity. It is critical to harvest ing losses are higher with hay, while
make quality silage? When a roughage alfalfa hay at the proper moisture level storage losses often are greater with
“heats,“ is there a loss of protein? depending on the bale package used. silage. Silage making generally is more
Questions About Failure to bale at the proper moisture expensive, and the crop has much
can result in leaf loss if too dry or less marketability than hay, however,
Roughages mold growth in storage if too wet. harvesting as silage reduces weather
1. What is forage quality? risks. The class of livestock being fed
Forage quality is a combination of 4. What lab analyses should one is also important. Growing calves can
the protein level as well as the digest- get on forages? utilize the extra feed value in silage for
ibility (energy) of a forage. A high- In most cases, an analysis for 1) growth compared to mature animals
quality forage allows increased cattle moisture, 2) crude protein, and 3) acid such as beef cows fed maintenance.
intake and digestibility, and enhanced detergent fiber (ADF for estimation 8. How can corn and milo crop
feed conversion. The best means of of energy value) is sufficient to bal- residue be most economically
evaluating the cattle performance ance diets properly. If alfalfa or any utilized?
potential of a forage is the product of forage shows substantial heat damage, Effective use of crop residues offers
its digestibility and intake (i.e., digest- browning or mold, it is recommended cattle producers a means of reducing
ible dry matter intake). to have an acid detergent fiber nitro- their feed costs, especially with the
gen analysis conducted as well. In beef cows. The most economical way
2. How important is forage addition, if the forage is to be fed to to use crop aftermath is to graze it the
quality? cattle that are physiologically chal- first 50 to 60 days after grain harvest
Forages can constitute 5 to 100 per- lenged (late gestation, early lactation, and then have adequate roughage
cent of beef cattle rations. Depending receiving diets), it maybe well to have stored to feed the cows during the
mid-winter months of January and and covering the silage to exclude air 11. Should I consider
February. Research shows that, in most and minimize top spoilage. Corn and ammoniating wheat straw?
cases, during the initial six to eight milo stover silages typically contain 5 Research at Kansas State and
week fall grazing period, gestating beef to 7 percent crude protein and 45 to other universities clearly shows that
cows can be grazed on corn and milo 55 percent TDN on a dry matter basis. ammoniation increases straw intake
stalks without the need of supplemen- The feeding value of stover produced and digestibility 15 to 25 percent,
tal protein, except that salt, phospho- under dryland conditions is generally and doubles the protein content of
rus and vitamin A should be fed. higher than that from irrigated grain wheat straw. These nutritional changes
When harvested crop residues are production. make ammoniated wheat straw com-
fed in winter months to pregnant cows 10. Can wheat straw be used in parable to prairie hay as a feedstuff.
that are within one to two months of beef cattle rations? Furthermore, KSU research indicates
calving, additional protein and energy Yes. Wheat straw is greatly unde- that it can be used as the sole forage
should be fed. Crop residues for lactat- rutilized as a feedstuff, particularly with mineral and vitamin supplemen-
ing beef cows do not supply sufficient in beef cow rations. It can be used as tation for beef cows before calving.
energy and should only serve as a the primary forage in dry cow rations Your county Extension agent can assist
small portion of the cow’s diet. and at low levels in lactating rations. you with the ammoniation procedure.
Another possible use of harvested For example, wheat straw can make 12. Can I make wheat and other
corn and milo stover is in growing up two-thirds of the ration when small grain forages into
rations, especially when other forages combined with a high-quality forage silage?
are scarce. Kansas State research shows such as alfalfa hay for dry cows. It can Extensive research at Kansas State
that either dry, chopped stover or constitute as much as one-third of the University has demonstrated that
stover silage can be fed as one-third of ration with quality hay for lactating small grain silages are excellent rough-
the roughage along with other higher cows. It has great potential for reduc- ages in growing and finishing rations.
quality forage with acceptable calf ing feed costs and stretching feed Maximum yield and total feed value
performance. But when corn or milo supplies in dry years. for beef cattle are obtained when
stover constituted all of the rough- Experience by Kansas produc- these forages are harvested in the soft
age portion (75 percent of the total ers indicates that the palatability of dough stage. At this stage of maturity,
ration), daily gains were only 0.75 to wheat straw is adversely affected by the crops usually can be direct cut or
1 pound, which would be unsatisfac- weathering. Thus, it should be baled swathed and chopped within one to
tory to many producers. Crop residues as soon after wheat harvest as possible. three hours at an optimum moisture
may also be used in feedlot rations Wheat straw may also be used as a content of 60 to 70 percent. Because
provided they do not exceed 5 percent partial roughage source in growing of the hollow stems and bulky nature
of the diet. and finishing diets. Straw needs to be of these chopped forages, the moisture
9. Can corn or milo stover be chopped prior to inclusion in mixed level should be at least 60 percent for
made into silage? rations, with an average particle length adequate packing and preservation. In
Grain sorghum stover is easily of not more than 1 inch. some cases, it may be necessary to add
made into silage, particularly if it is Optimum utilization of wheat water, especially to the surface layer, to
chopped shortly after grain harvest. straw results when used in combina- ensure a denser pack before to cover-
Adequate moisture content in the tion with high-quality forage such as ing the silage.
stover is very important for efficient alfalfa hay. Substitution of straw for The energy content of cereal crops
ensiling. Shortly after grain harvest, alfalfa hay should be done on a forage cut in the soft dough stage is directly
milo stover will have 60 to 70 percent neutral detergent fiber (NDF) basis, related to the proportion of grain to
moisture, so it can be direct chopped rather than on a weight or percentage forage in the silage. Typically, wheat
and ensiled without the need to add basis. In Arizona research with grow- silage contains about 35 percent grain
water. When corn stover is chopped ing and finishing steers, daily gain and in the silage dry matter and has a
immediately after grain harvest, it feed gain were optimized when wheat feed value of about 80 percent of corn
will usually contain 50 to 60 percent straw and alfalfa hay each contrib- silage. In contrast, barley silage con-
moisture, but that drops rapidly within uted 50 percent of the forage NDF. tains up to 45 percent grain and has 95
a few days after grain harvest. In most Another consideration when using to 100 percent the energy content of
cases, water will need to be added to wheat straw is protein supplementa- corn silage in growing rations.
chopped corn stover to ensure effective tion. Straw is very low in protein so as Silages made from oats, rye and
packing and fermentation. As with all the level of straw in the diet increases, triticale are lower in grain content and
forages, successful stover silage man- protein supplementation also must have an energy content only about
agement consists of adequate moisture increase. 70 percent that of corn silage. When
content, fine chopping, firm packing using these three crops in growing
rations, it is often advisable to harvest order to preserve the forage dry matter Questions About Crude
them in the late boot stage when the and minimize fermentation losses. Protein and Urea
forage is higher in nutritional value, The most promising silage inoculants
although yield will be reduced about provide at least 100,000 live lactic acid 1. What does the term “crude
40 percent and the forage needs to be producing bacteria per gram of ensiled protein” mean?
wilted prior to chopping. Small grain forage, and consist of Lactobacillus and The term crude protein includes all
silages are higher in crude protein Pediococcus species, and/or Streptococcus nitrogenous compounds in a feed. The
than corn or forage sorghum silages faecium. These products produce small, crude protein content or equivalent of
and usually contain 9 to 11 percent at but significant, reductions in silage a feed is calculated by first determin-
the dough stage and 14 to 16 percent dry matter losses and enhanced silage ing its nitrogen content and then mul-
when cut in the boot stage. stability at feed-out. Silage crops tiplying the result by 6.25. On average,
13. What is the status of that are difficult to ferment, such as the nitrogen content of natural protein
harvesting high-moisture hay? alfalfa, show the greatest response to is approximately 16 percent
Harvesting hay at moisture levels inoculants, while corn and high grain- (100 ÷ 16 = 6.25).
exceeding 20 percent, compared to containing sorghum silages show the 2. What does the term
normal field-cured forage containing least. Their economic benefit depends “digestible protein” mean?
14 to 18 percent water, has several on the level of response, feed value Digestible protein indicates that
advantages, especially with alfalfa of the silage, and cost of product and portion of crude protein that is digest-
hay. First, leaf loss is greatly reduced, application. ed and absorbed into the body.
resulting in a higher quality, more The ammonia-containing addi-
nutritious feedstuff. Second, baling at tives—Cold-Flo NPN (anhydrous 3. How does the protein
higher moisture allows producers to ammonia) and Pro-Sil (an ammonia, digestibility of various
harvest earlier, with less chance of rain molasses and mineral suspen- feedstuffs compare?
damage during unpredictable weather. sion)—are the only two corn silage The digestibility of protein in low
These advantages must be weighed additives currently approved by FDA quality roughages such as straw, corn
against the extra time, labor and for both safety and effectiveness. stover, cottonseed hulls and corn cobs
expense of hay preservative applica- Thus, extensive university research has is quite low. In contrast, the protein
tion, equipment and product to help been conducted with these products, digestibility of high quality forages,
prevent excessive molding and poten- and both are economically beneficial grains and oil seed meals is relatively
tial fire in the hay crop. when properly used. These additives high. The digestible protein content of
increase the crude protein of silage 3 some common feedstuffs is shown in
14. Are silage additives necessary to 5 percentage units, reduce mold and the following table.
to make quality silage? fungus growth, decrease protein degra-
The basic principles for making dation in the forage, and substantially 4. Do I need to feed a mixture of
quality silage are harvesting the crop increase the lactic acid content and protein sources to ensure that my
at the proper stage of maturity and silage stability in the silo and feed cattle are obtaining the proper
moisture content (60 to 70 percent), bunk. However, apparent dry matter balance of amino acids for maxi-
chopping it finely, filling the silo rap- recovery may be reduced somewhat, mum performance?
idly, packing it tightly, and covering especially with overly wet silages. For most pasture and range situa-
the silage with black plastic. These 15. When a roughage “heats,” is tions, the answer is no, given the lim-
keys to success optimize silage yield there a loss of protein? ited production potential of grazing
and nutritional value while minimiz- Failure to adequately exclude air cattle and the ability of rumen bacteria
ing harvesting and storage losses. For during the ensiling process, or baling to provide a quality protein source
example, covering bunker silos will hay that is too wet, will cause heat- in sufficient supplies to meet cattle
dramatically reduce top spoilage by 65 damaged forage—created by fixation needs. With growing diets where
to 85 percent. of the protein to fiber when tempera- calves are challenged for performance,
There are a wide variety of silage tures exceed 140 F. This heat-damaged research shows significant increases in
additives and preservatives, rang- protein is not digested by animals. efficiency of protein utilization early
ing from organic acids and nutritive Unfortunately a standard crude pro- in the feeding period by mixing two or
products to bacterial and enzyme tein analysis will not show the degree more escape protein sources and urea
inoculants sold as aids to fermenta- of heat-damaged protein present. together. This has been attributed to
tion. The two most popular types are However, forages can be analyzed the high level of some essential amino
microbial and Non Protein Nitrogen for acid detergent insoluble nitrogen acids in rendered animal protein by-
additives. Effective bacterial inoculants (ADIN) to evaluate the amount of products, particularly blood meal and
should stimulate lactic acid produc- unavailable, heat-damaged protein. feather meal.
tion and rapidly lower silage pH in
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