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ADVANCED BREED ING
The development of IVF in cattle is being led
by Stuart Mullan and colleagues at Paragon's
Advanced Breeding base at Newbiggin near
Penrith. The initiative is a five year grant-aided
project with the Technology Strategy Board
(TSB), whose goal is ‘to accelerate economic
growth by stimulating and supporting
business-led innovation’. Paragon Veterinary
Group is the lead organisation for the project,
supported by three other consortium members;
XLVet UK Ltd., University of Nottingham and
Cogent Breeding Ltd.
‘OPU was initially developed so that high
genetic merit 'no-hoper' cows could be
brought back into their owners' herd breeding
programmes’ says Stuart. He explains how it
soon became clear that this technique could
quickly become a mainstream component in
the cattle breeder's toolbox.
Stuart reports acceptable pregnancy rates in
the transfer of fresh IVF embryos to recipients.
The main focus of the research team's work is
now to concentrate on freezing embryos and
to continue improving subsequent pregnancy
rates. Another key focus of the project is to
create viable IVF embryos using sexed semen
to produce exclusively heifer calves. Typically,
he says each OPU egg collection yields six to
eight viable eggs. Extracted eggs require a
24-hour period of maturation in a culture
medium before fertilisation. Resulting embryos
are cultured for six days in a nutrient medium
and are then ready for implantation in
recipient females that have been synchronised
in parallel. Stuart reckons approximately 35%
of extracted eggs are likely to make viable
transferable embryos.
The project is now in year two of its five
year TSB programme. The main goal is to
make a commercial cattle IVF service
available to owners of dairy and beef herds
seeking accelerated advancement in cattle
genetic merit. In addition to the core scientific
R&D work, investment is also planned for
developing facilities and equipment,
staffing and training, and ultimately sales
and marketing.
Stuart says the vision is to have five
OPU/IVF teams around the UK within the
next five years, with an associated network
of XLVets practices implanting embryos into
recipients. Stuart also suggests that IVF could
largely replace MOET as the first choice
technique in accelerated genetic progress
in cattle, and is resolute that the UK can
become a global leader in this technology
among a number of rival programmes in
other countries.
AUTUMN 2013 ISSUE
LIVESTOCK MATTERS
18
IVF in cattle
will soon become commercially viable for mainstream UK
dairy and beef herd thanks to a project being led by XLVets member
practice, Paragon Veterinary Group.
“Mattia stopped producing
fertile embryos three years
ago. Using IVF she is now
producing pregnancies
again at 15 years of age”
Above:
Applevue Rudy Mattia EX97(4)
Right:
An IVF
calf born at
Riverdane
Mark Nutsford
Riverdane Herd, Cheshire
Case study 1
“Tina was a cow
who had been
difficult to get
in calf after her
first pregnancy
and only ever
produced 2 embryos by
conventional flushing.”
Recent success using the Ballycairn
herd in Northern Ireland has been
very encouraging, Ballycairn
Goldwyn Tina VG89 (305d, 12,485kg,
5.22%F, 3.76%P, PLI £194) has now
produced nine successful pregnancies
from vitrified (frozen) IVF embryos,
transferred by Stuart Mullan.
This key part of the IVF process is the same
as for MOET recipients and is consequently
well proven and understood by specialist
cattle vets. Recipient females are usually
treated with a controlled intra-vaginal
drug release device, which releases
progesterone at a precise rate, passing
through the vaginal wall into the blood
stream. Progesterone suppresses the release
of other reproductive hormones, thereby
suspending the oestrous cycle temporarily.
After the prescribed number of days,
removal of the device causes a sharp
drop in blood levels of progesterone. This
triggers resumption of the oestrus cycle, in
preparation for transfer of embryos into
recipients at the optimum time.
Recipients receiving IVF embryos need
to be managed to an even higher standard
than those receiving conventionally
produced embryos to achieve maximum
pregnancy rates.
Key factors in recipient
management are:
l
Nutritional status
- It is very important
to have recipients on a rising plane of
nutrition. The diet should be based on
long fibre with a moderate protein
content and well supplemented with
minerals and trace elements.
l
Body condition
- Recipients should be
maintaining or increasing body weight,
but not be over fat. Animals losing
condition for whatever reason, are likely
to give poor results.
l
Age of recipient
- Maiden heifers will
generally give 5-10% better pregnancy
rate compared to cows, however, in
some situations this can be countered by
the improved calving ease of cows.
l
Maiden heifers should be 15 months
or older, cycling and at least 350kg
in weight.
l
Cows should be fourth calvers or less,
past peak yield and have no history of
health or reproductive problems.
l
Disease status
- Infectious diseases
such as BVD, IBR and Leptospirosis can
have a disastrous effect on an ET
programme and control measures should
be discussed with your Vet.
l
It is inevitable that some losses will also
occur after positive pregnancy
diagnosis. A resorption/abortion rate of
5% from six weeks is considered normal.
Most losses occur early in pregnancy
and are spontaneous, however, it is wise
to investigate known abortions in case
the cause is infectious.
Recipient management
Case study 2
Activf-ET
is the company that has been
created to commercialise the research, and
to communicate and market the technologies.
Initial centres are being established in Cumbria,
Cheshire and Yorkshire, for further details
contact Activf-ET:
T:
01228 710208
E:
info@activf-et.com
www.activf-et.com