The Rural Voice, 1980-11, Page 29ADVICE ON FARMING
Synchronized cycle
benefits producer
Heat synchronization techniques could
soon make Canadian sheep producers
more efficient.
"By introducing a synchronized estrus
cycle, it is possible to breed ewe Iambs at
seven to eight months of age," explains
Louis Ainsworth, a research scientist at
Agriculture Canada's Animal Reserach
Institute in Ottawa.
"Lactating ewes and dry, mature ewes
can be bred on a year-round basis," Dr.
Ainsworth says. "And you can increase
each ewe's lambing frequency.
"Controlled reproduction using heat
synchronization produces a compact
lambing period. This allows for long-term
planning, efficient scheduling of feed and
labor requirements, and uniformity in the
Iamb crop," he says.
But methods used to control the estrus
cycle must be simple to apply, in-
expensive and effective. Conception and
birth rates achieved must be at (east as
high as those possible using normal
breeding methods.
Dr. Ainsworth and his colleagues at the
Animal Research institute are testing
methods of controlling reproduction
developed in other countries, and adapt-
ing them to Canadian conditions.
The standard method of control of the
estrus cycle in sheep involves the
insertion of a hormone -treated polyure-
thane sponge in the vagina for 12 to 14
days. At the end of this period, the
sponge is removed and the ewe is
injected with PMSG (pregnant mare
serum gonadotrophin).
In trials using adult ewes and natural
mating. 85 to 90 per cent of the
hormone -treated ewes bred during the
August to November period lambed.
Lambing was divided into two distinct
periods of four to five days each,
depending on whether the ewes con-
ceived during the synchronized or the
next estrus.
"Although ewes do come into estrus
shortly after the sponge treatment with-
out the use of PMSG, a low dose (500 1U)
results in a more predictable and precise
synchronization. And it induces a mild
super -ovulatory effect which slightly
increases the likelihood of twins and
triplets," Dr. Ainsworth says.
"To get acceptable lambing results,
the use of PMSG is essential after sponge
treatment of ewe Iambs, and for ewes
treated at times when they would not
normally cycle -- for instance while they
are milking or outside the natural
breeding season, " he says.
Animal Research Institute scientists
are also developing management and
feeding programs which would comple-
ment controlled reproduction methods.
Brucellosis control
starts at home
An aim of the Animal Disease and
Protection Act is to control disease among
animals and it was recently enforced to
bring charges against a Blyth area farmer.
Clarence Poortinga. of R.R. 3, Blyth,
was sentenced in September in Goderich
provincial court, for failing to keep
records of purchases and sales of
cattle. Mr. Poortinga was originally
charged with 16 violations, but received a
suspended sentence on 15 of the
offences. He was fined $500 on the
remaining charge.
According to Dr. W.J. Thompson, a
veterinarian with Agriculture Canada,
Seaforth office, farmers are required to
keep records of all cattle transactions.
That way, if diseased cattle are dis-
covered, officials will eventually be able
to identify the source.
"We check milk four times a year,"
explained Dr. Thompson, "and we also
check the cream shippers. Slaughter cows
MAILBOX
OF THE
MONTH
belongs to:
tludson Bros. Orchards, near M eaford,
in Grey County.
are back -tagged and when they're
slaughtered there's blood sample taken
from them. The information is recorded
and credited to the herd."
After a serious outbreak of brucellosis
a few years ago, federal officials were
given more power through the act to
control such disease.
"Starting in '76 or '77, a lot of cattle
were under quarantine in Ontario, and
now the infection has been beaten
down," said the veterinarian. "Being
able to trace the disease has been
beneficial. We don't have any figures on
the sort of result it's bringing, but we
know it's something we have to do."
A farmer with diseased cattle will see
the effects in several ways.
"One is the economic impact on cattle
where there is certainly a lack of
production," explained Dr. Thompson.
"The bacteria has an effect on the
reproductive organs as well," he added.
"As a result of that, animals affected lose
their calves. The calves are usually dead
when born, but sometimes they live for a
short while. The discharges an animal
has after are very infectious to other
animals.
"We find as dealers are moving cattle
from place to place past experience has
proven to us that cattle moved about are
more susceptible to disease." Dr.
Thompson said Brucellosis can be fatal,
but that seldom occurs.
Humans can also contact the disease
(e.g. through cuts). In humans, the
disease is called undulant fey.r.
"In humans it is not usually fatal, but:
it can be a long lasting, persistent type of
infection," said D. Thompson.
The name for the disease is derived
from the word 'undulate', which means to
rise and fall in waves, and refers to body
temperature going up and down in
someone who has contracted the in-
fection.
THE RURAL VOICE/NOVEMBER 1980 PG. 27