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The Midwest Cattleman · February 23, 2023 · P26
Forage Testing is Good Management
By Elizabeth Cronin
All living things require ture and range,
nutrients for survival. The hay, silage) are
most basic of these are pro- the backbone for
tein, energy, vitamins, miner- meeting this nu-
als, and water. Testing forage trient demand.
and feed for nutrient quality Protein con-
helps ranchers ensure they tent is the first
are meeting nutrient re- nutrient ranch-
quirements for optimum beef ers must consider
cattle performance. in forage. In the
“Compared to a human, rumen of the cow,
a beef cow needs to be sup- bacteria require
plied with a massive amount protein in order
of nutrients daily to meet to efficiently and
requirements for movement, completely digest
fetal growth, temperature forage. If protein
maintenance, digestion, milk levels are not
production and other func- meeting animal
tions,” says James Rogers, requirements, for-
North Dakota State Univer- age intake is re-
sity Extension forage crops duced and forage volume of all nutrients and calories, meaning 9.1 million
production specialist. digestion can be incomplete, often gets overlooked, says calories must be supplied
Young cows require ad- which limits intake of other Rogers. A common term for every day to meet this cow’s
ditional nutrients for body nutrients such as energy. expressing the energy re- maintenance energy require-
growth until they reach ma- Once protein requirements quirement of the cow is total ments.
turity. Thin cows require ad- are met, the focus should be digestible nutrient (TDN). “When this same cow
ditional nutrients to restore on meeting the cow’s needs TDN requirements can be moves from the middle third
body condition. For beef cow- for energy, which is required expressed as pounds per day to the last third of pregnan-
herds, forages (grazed pas- by the cow in the largest required or as a percentage of cy, the NEm jumps from 9.1
the daily dry matter intake. Mcal to 12.0 Mcal daily,”
“TDN works well for ration says Rodgers. “That is 12
balancing and for describing million calories per day just
energy content of a feed or for maintenance or roughly
forage,” says Rogers. “How- 1,091 cups of salad, assum-
ever, it does not give you a ing that a cup of salad con-
real feel for the volume of en- tains 11,000 calories.”
ergy required by a beef cow. Another leap in energy re-
A more descriptive term is a quirements occurs when the
calorie, which describes the cow moves into calving and
amount of energy required lactation. Then NEm goes
by an animal or the amount from 12.0 to 18.6 Mcal if the
of energy supplied by a feed cow is producing 25 pounds
source.” of milk per day. As nutrient
In beef nutrition, net en- requirements increase, for-
ergy for maintenance (NEm) age quality and/or supple-
and/or net energy for gain mentation should increase. A
(NEg) describes these val- forage that barely met nutri-
ues. NEm describes energy ent requirements at the mid-
requirements for daily cow dle third of pregnancy will no
maintenance. If any energy longer meet requirements at
is left over after maintenance calving.
needs are met, it goes to NEg. These numbers do not
The unit of measurement consider temperature, wind,
for net energy in beef cow mud, snow, or other envi-
requirements is a megacal- ronmental factors that can
orie (Mcal). Human energy further swell requirements.
needs are also expressed in Testing forage and feed for
calories but in kilocalories nutrient quality provides
(kcal). A human male needs ranchers with the knowledge
2,700 kcal each day or 2.7 of what nutrients they are
million calories per day (1 supplying to their cattle on a
kcal = 1,000 cal). By compari- daily basis.
son, a 1,200-pound cow in the Echoing the saying of an
middle third of pregnancy re- old football coach about the
quires 9.1 Mcal/day for NEm. forward pass, Rogers says
A megacalorie is 1 million that there are three possible
