The Rural Voice, 2006-01, Page 18High quality forage is an essential part of modern dairy management. For beef, it's a necessary expense.
Forage: both sides
Cattle were built for taking grass and cellular material
and breaking it down into digestible food. For dairy producers that means
quality forage is the keg to milk production. For beef feedlot operators, that's
a necessary obstacle to be managed
By Keith Roulston
Two meetings, two days apart.
Two American speakers
imported to tell producers how
to tweak their feeding programs to
get the highest production from their
cattle. Two totally different views on
feeding forage.
For Everett D. Thomas of the
William H, Miner Agricultural
Research Institute, in Chazy, New
York, producing high quality forage
is the key to high milk production in
dairy cattle. But for Steven Rust of
Michigan State University who spoke
to feedlot operators at Beef
Symposium 2005 in Brussels,
December 1, forage is a bulky,
expensive, low energy feed that
should be fed in minimum allowable
amounts to allow cattle to survive on
a high protein diet.
For the feedlot operator, Rust
says, roughage dilutes the energy of a
14 THE RURAL VOICE
high protein diet, slowing the rate,
and increasing the cost of gain. The
slower rate of gain means cattle
spend more time in the feedlot,
costing more in interest charges on
operating Loans.
But for Thomas, who spoke at
Forage Focus 2005 in Shakespeare,
November 29, high quality forage is
the key to high milk production.
"Cows will do better on a high -
forage diet," he said.
Another speaker at Forage Focus
explained how forage plays its role in
milk production. Bill Woodley, Shur -
Gain technical Services Director,
explained acetic acid is the key
building block in about half the milk
fat. This acetic acid is the by-product
of rumen fermentation of
carbohydrates, especially those from
fibre. Cellulytic microbes produce
the acid.
Rumen pH is the tipping -point for
the production of short -chain fatty
acids such as volatile fatty acids
(VFA), Woodley said. The ideal pH
for a dairy cow is between 5.8 and
6.2. If pH levels are lower than 5.8
the bacteria that digest fibre can be
killed off, he said.
The cow's digestive system works
on a two-stage system to absorb
easily digested feed contents like
starch, and sugars like glucose and
fructose, and a slower process to
break down plant cell walls. The
work is accomplished by different
bacteria that take on different jobs.
The digestible portion of the forage
provides carbohydrates for the
bacteria in the rumen. Digestible
NDF is very important for cellulytic
bacteria which produce acetic acid.
Fibre is. so important in forming
the fibre mat in the rumen which