The Rural Voice, 1979-07, Page 33Management can
prevent cattle bloat
Proper pasture management can help
prevent bloat in cattle, says Professor R.S.
Fulkerson, Department of Crop Science,
University of Guelph. He recommends
equal balance of alfalfa and grass as one of
the best ways to reduce distress or deaths.
"A good reason for maintaining fifty
per cent grass content is its bloat -deterring
substance called tannins," says Professor
Fulkerson. "Tannins help prevent the
build-up of gas in a frothy foam in cattle."
Although bloat can occur throughout the
grazing season, the critical time is mid-
summer when high temperatures promote
lush alfalfa growth and inhibit grass
growth. The resulting imbalance in the
alfalfa -grass mixture can increase chances
of bloat. Professor Fulkerson adds that
ladino and red clovers can also be
bloat -causing factors.
"Cattle should be full before they are
turned onto lush pasture," advises Pro-
fessor Fulkerson. "Feeding them hay all
summer helps prevent bloat because the
dry matter mixes with the succulent
greens. Hay should be readily accessible in
bunks in the pasture."
Another preventive measure is green -
chopping pasture. This method requiqres
cutting and hauling the fresh herbage to
the cattle. There is less chance of bloat
when cattle are fed a ready-made, chopped
mixture of alfalfa and grass.
"This system is 30 to 50 per cent more
efficient than free -choice grazing because
it provides high herbage intake, avoids
selective grazing of alfalfa, and prolongs
the life of the pasture," says Professor
Fulkerson. "It works best on dairy farms
where the equipment may already be
available, or where the field location is
inconvenient for cattle grazing."
Professor D.N. Mowat, Department of
Animal and Poultry Science, says there are
products in local feed stores which help
prevent bloat. They are fed as top
dressings on grain rations.
"A certain amount must be fed to each
animal every day," says Professor Mowat.
"Although this is more practical for
dairymen, beefmen could also feed a small
daily ration from a bunk."
A simpler solution for beefmen is to
grow legumes such as bird's -foot trefoil or
crown vetch that do not cause bloat. In the
1979 Ontario Ministry of Agriculture and
Food Field Crop Recommendations, Pub-
lication 296, cultivation of bird's -foot trefoil
is stressed, particularly where long-term
pasture production is desired.
Currently, there are no bloat -safe vari-
eties of alfalfa but Professor Fulkerson
foresees that research will eventually make
them possible. In the meantime, sound
management practices will help prevent
pasture bloat in most cattle.
Scours vaccine
could save $24 million
A vaccine to combat scours, a form of
diarrhea that infects newborn calves, has
been developed by the Veterinary Infec-
tious Disease Organization in conjunction
with Connaught Laboratories.
The announcement of the new vaccine
was made recently at the annual conven-
tion of the Saskatchewan Stock Growers
Association.
The new vaccine fights the E coli form of
bacterial calf scours. Research to develop
the drug began in Saskatoon in 1975 under
the direction of Dr. Stephen Acres, and the
first field tests were held this spring.
The date will be presented to the federal
government and the vaccine should be
licensed by September. It's estimated
producers could save as much as $24
million in 1980 when the vaccine is
available on the market.
Some silage additives
reduce nutrients
Some silage additives may in fact reduce
levels of forage nutrients rather than
enhance their production, says an Agricul-
ture Canada scientist who recently com-
pleted studies on one such product.
L.J. Fisher, an animal nutrition special-
ist at Agriculture Canada's research
station at Agassiz, B.C., studied a silage
additive that was claimed to improve the
quality of the final product.
"Basically, we found that the additive
appeared to stimulate fermentation of the
silage, but compared to untreated silage, it
didn't improve performance of milking
cows," Dr. Fisher says.
A recent trial at the station involved a
silage additive in which the active ingred-
ient was a dried culture of ' lactic acid
bacteria which, when ensiled, was sup-
posed to increase the rate of lactic acid
production and prevent the formulation of
other acids that cause strong -smelling
silage.
"We added this product to wago' loads
of freshly -chopped orchardgrass silage at
the recommended rate of one kilogram per
tonne," Dr. Fisher says. "It was mixed
with the forage as it was blown into the
silo."
A control silo was filled with untreated
forage.
Silo temperature and rate of runoff were
measured daily, and revealed a faster rate
of fermentation for the grass ensiled with
the additive.
"We fed the two silages to 16 lactating
Holsteins for six weeks," the researcher
says. "Dry matter intake, milk yield and
milk constitution were the same for both
silages. There was no apparent advantage
in animal performance when the silage
additive was used."
Dr. Fisher says an important finding was
that the digestibility of dry matter from the
total ration of cows fed treated silage was
significantly less than for cows fed the
untreated product.
"This depression in digestibility for the
grass silage treated with an additive
indicated that excessive fermentation may
in fact reduce forage nutrients," he
concluded
Fertilizing with manure
back in style
Fertilizing crops with manure is coming
back into style, particularly with steadily
rising commercial fertilizer costs.
Charlie Crober, an Agriculture Canada
fertilizer specialist, said, "During the
1960's and into the early 1970's, fertilizer
prices declined steadily with the result that
manure use dropped."
But now the rising cost of resources is
forcing many farmers to take another look
at manure.
At the going prices, twenty tons of
manure are worth about $50, according to
Mr. Crober, and three cattle will produce
that much in a year.
The manure already contains nutrients
since cattle only use 25 per cent of what is
contained in their feed. As well as
nitrogen, phosphorus and potash, manure
contains the trace elements plants need to
develop normally.
Mr. Crober said manure must be stored
properly to resist nutrients washing away.
THE RURAL VOICE/JULY 1979 PO. 31