a matter of management...
“Six out of six and nine out of eleven conﬁrmed pregnancies!” A sms from a big Boran
breeder telling me about the embryo transfer results of his two best cows.
Fifteen superior calves from a single ﬂushing.
Are these outstanding pregnancy results pure luck or is there a secret recipe?
rom my experience of over 2000 flushings, the average amount will do so repeatedly. It also runs
of viable embryos per cow flushed is 6.7. I have flushed Boran in the family; daughters of fertile
cows producing up to 43 usable embryos in a single flush, and mothers will also have a better
on the other hand I have flushed numerous cows giving nothing. chance to be successful flushers.
How is this possible?
Age of the donor is an important
From my experience of over 6000 embryo transfers, the average amount factor for results. Cows that are
of confirmed pregnancies varies a lot from one day to the following, from 4 to 8 years old usually produce
one farm to another and from one season to the next. Several transfers the most embryos. In comparison
resulted in a 100% conception rate.Then there were also days with very to this ideal age category, heifers,
disappointing results. Why so much variation? first calvers and old cows react
more unpredictable to the super
There is an average in all flush and transfer results. It is this average that
you should work on and aim for.
With a suckling calf or during
There are numerous factors influencing the success of an embryo pro-
peak lactation, cows in general
gram. Some of them you can control, and some are out of your hands.
give less embryos. In the case of
Rain, drought, cold, wind, heat and many other acts of nature can cause
a donor cow having a calf at foot,
a big disappointment in the embryo results obtained. Most farmers have
the program should not be start-
managed to accept and live with the unpredictable ways of nature. If
ed before 2 months post calving
you can’t handle disappointments, you should rather not do embryo
to give enough time for the uterus
flushings because no human being can control nature. We can also not
to recover and the ovaries to re-
predict what the weather will do in one month’s time when fertilization
takes place or when the growing embryos are at their most vulnerable
stage. To improve your embryo quantity
you can do the following:
Let’s rather focus on the ingredients that you can influence and that can
make a difference in your embryo quantities and which can improve • Choose the most fertile cows.
your conception rate.
• Choose cows between 4 and 8
Success ingredient no.1: years of age.
Donor selection • Wait at least 2 months after
Donor cows are valuable cows that get special treatment to super ovu- calving before starting the pro-
late and produce more than one embryo. Unfortunately, not all cows gram.
react on the super ovulation program. Highly fertile cows that calve • Wean the donors’ calf before
every year have better chances. Usually the cows that produce embryos the program starts.
God’s gift to cattlemen BORAN 21
• Choose cows that have given embryos before. • Choose a recipient between 4-8 years
• Choose cows that have mothers that flush well. of age
• Choose cows in a rising plane of condition. • Select a breed that is best adapted to
• Do not choose fat cows. Fat animals usually flush poorly.
• Do not use a Jersey as a recipient for
• If flushed before, individualise (i.e. increase or decrease) the a Boran embryo
amount of super ovulation hormone given.
• Vaccinate your recipients on time
• Make sure the uterus has recovered fully after calving.
• Give your recipients more than
Success ingredient no.2: 2 months to adapt
• Minimize stress factors
Recipients are probably the most important ingredient.
• Record standing heat
A good recipient is worth the equivalent of one of your best stud
Boran cows, as she can calve and raise the most valuable Boran • Wean the calves before using the re-
calf on the farm. She must be a very fertile cow to conceive the cipients
very expensive embryo. Choose recipients that have calved first • Prevent sudden changes
in your herd, i.e. conceived first. Do not use animals that have not
taken during the breeding season. It is a clear sign of infertility or Success ingredient no.3:
an indication of a health problem. The Boran embryo
The age of your recipient needs to be taken into consideration; A sperm cell fuses with an egg cell to
4 to 8 year old cows that have calved every year are the best produce a single cell on the first day of
recipients as they have proven themselves with calving ease, its life. The single cell then divides into 2,
milk production and fertility. When using heifers as recipients, then 4, then 8, etc. until it usually reaches
make sure they are big/heavy enough and have reached puberty.
32 to 64 cells on day 7. The embryo at
Daughters of fertile mothers will be the first choice.
this stage can not be seen without the
The breed of the recipient is not as important as its adaptation help of a stereo microscope. (10-50 times
to the farm and its feed requirements.The only breed that seems magnification). At day 7, the embryo is
to have an inherent problem to retain a Boran embryo is the still protected inside the egg cell’s origi-
Jersey. A significantly lowered calving rate has been observed in nal shell. No cell differentiation has taken
this breed. place and thus no organs have formed
Recipients should be cared for as if being SP animals and their yet. Because of this protected stage, the
vaccinations should be up to date. Diseases like BVD, IBR and embryos can be flushed, washed, manipu-
Brucellosis can cause early or late abortions of valuable Boran lated and frozen with minimal damage.
progeny. Any disease or infection causing a fever reaction can Due to multiple ovulations taking place
result in the loss of the embryo/foetus. (E.g. Lumpy Skin Disease, not all egg cells are of good quality. Usu-
3 Day Stiff Sickness, Redwater, Heartwater, Gallsickness etc.) ally 30% of the total amount of structures
The adaptation time for potential new recipients should not be recovered during a flushing will be either
less than 2 months. It takes a lot of time for the recipient to adapt unfertilized and/or dead. During the first
to a new farm, a new herd of cows and to different nutrition. 5 days inside the cow, the embryo is at its
It is good practise to let your cows get used to the crush, with- most vulnerable stage. Any stress, envi-
out exposing them to traumatic events. ronmental change or nutritional deficien-
cy can cause either individual or multiple
The stress that any change causes can be detrimental to the cells to die. It is this exact phenomenon
transferred embryo and could decrease your conception rate. that gives us the means to grade em-
When synchronizing recipients, it is very important to record bryos. Grade 1 embryos are classified as
the time of standing heat. Recipients may not show heat at all or embryos that contain less then 15% dead
may come on heat too late or too early and thus not be suitable cells. Grade 2 embryos contain between
for an embryo. 15 and 50% dead cells. Grade 3 embryos’
have more than 50% dead cells.
To increase your conception rate, do the following:
• Select the most fertile recipients Every living embryo cell secretes a pro-
tein/hormone that is essential to signal
• Select a recipient with good milk its presence to the ovary of its recipient
22 BORAN God’s gift to cattlemen
mother. By implication this means that the more liv-
ing cells present, the stronger the signal. The stron-
ger the signal, the better the chance for the mother
to recognize her pregnancy.
In general, grade 1 embryos have a 50-60% chance
to successfully signal their presence. Grade 2 em-
bryos usually only have 30-40% success.The grade 3
embryos have less than 30% retention rate due to
a weak signal.
Fresh embryos mostly have a 10-15 % better con-
ception rate than frozen embryos of the same grade
(when transferred within 8 hours from flushing and
kept in a special holding medium.) There is indi-
vidual variation in embryo viability between different
cows. Embryos are classified under the microscope
Morula grade 1 embryo with 15 % dead cells. as Grade 1, 2 or 3 but the grade 1 embryos from
one specific cow may all conceive when transferred
where another cow’s grade 1 embryos may con-
ceive very poorly or can even fail to conceive. Some
cows thus produce stronger embryos than others.
Research now shows that the reason for this is
probably due to a higher amount of detrimen-
tal prostaglandin present/released in the uterus in
those cows during flushing.
Direct UV-light is harmful to embryos. Therefore
it is essential to keep the embryos out of sunlight.
The slightest amount of poison will kill embryos
instantly. They are extremely susceptible to most
chemicals like: fly poisons, dips (organo phosphates,
pyrethroids etc.) and cleaning agents. Pour on dips
are absorbed systemically and can decrease embryo
7 day old embryo’s contain usually 32-64 cells. conception when administered close to transfer
To maximize embryo production and conception:
• Use fresh semen to inseminate the donor cows
• Use 2 different bulls to AI the donor cow
• Transfer embryos fresh
• Transfer fresh embryos within 8 hours
• Transfer grade 1 embryos
• Identify and flush cows that give ‘strong’ embryos
• Provide shade and good facilities
• Do not dip recipients and donors with a ‘pour
on’ close to the flushing and transfer date.
• Make sure that no chemicals or poisons are near
Top left: Morula embryo
Top right: Degenerating dead embryo
the embryos at any stage
Bottom left: Embryo that died at 4-cell stage • Use fresh semen for the donor cow insemina-
Bottom right: 16 cell embryo that seems to struggle to stay tion
alive. Cells are falling apart.
God’s gift to cattlemen BORAN 25
Deficiencies present themselves as a high
percentage unfertilized or dead embryos
Too much is also not good and presents
itself in a similar way. Be careful not to
over supplement either.
Flushing Drinking water should be tested as it
is commonly found that substances like
• If possible use 2 different bulls to inseminate the
heavy metals or nitrate in the water cause
donor cow with
decreased fertility in a herd.
Success ingredient no. 4: What to do:
• Use a nutritionist to evaluate and for-
Nutrition is everything. What you put in is what you get out. mulate a balanced diet for the specific
When it comes to food; the donor, the recipient as well as the needs of your herd.
embryo has very specific needs. It is important to have the do-
• Draw blood to test mineral levels.
nor and recipient on a rising plane of nutrition that increases or
maintains body condition. Under no circumstances should they • Supplement deficiencies (esp. selenium!)
loose weight. A balanced diet with supplementations of essential • Minimize urea content.
minerals (e.g. selenium, copper, Zink, magnesium and manganese) • Supplement Vitamin A, D and E.
vitamins (e.g. vitamin A, D and E) and essential fats containing • Add or dose essential fats/oils con-
Omega 3, 6 and 9 is a minimum requirement. You can use a for- taining Omega 3, 6 and 9.
mulated bovine fertility pack to add some of the above named
• Maintain or increase the body condi-
minerals. The ration should contain as little urea (ureum) as pos-
tion score of donors/recipients.
sible. Urea can change the uterine PH which can hamper embry-
onic development and survival. • Test your water source.
• Continuous supplementation of es-
It is advisable to test at least some donors and recipients for se-
sential minerals, vitamins and fats is
lenium, copper and Zink levels. If possible, also find out what your
essential for 4 months before flushing
magnesium, manganese and chrome levels are. Micro- and macro
minerals play a key role in fertility and fertilisation.
It is essential to continually feed a totally balanced diet, as the Success ingredient no.5:
development of the egg cell from origin to ovulation takes about Good facilities
120 days (4months). At any stage a deficiency in the diet can ham- For preparations and flushings to be suc-
per or damage the developing/forming process which in turn can cessful, good facilities are essential. Proper
cause an irreparable defect. facilities improve results. Sorting camps
26 BORAN God’s gift to cattlemen
and a strong crush with a neck clamp are
the bare essentials. A small gate behind
the neck clamp is recommended for easy
access to the rear of the cow.
To restrict movement of cows during
preparations, flushings or transfers, suf-
ficient spacers for the ‘blocker-pole’ are
required. Sun and rain cover are neces-
sary to protect the embryos from UV
The microscope and laboratory equip-
ment requires a clean room with power
outlets. The optimal required room tem-
perature for embryo survival is between
20 and 30 degrees Celsius. Hot and cold
water should be available to warm flush-
ing liquids and embryo holding medium.
It is clear that a successful flushing de-
pends on the DONOR, the RECIPIENT,
the NUTRITIONAL REQUIREMENTS,
the EMBRYO quality, the FACILITIES and
most of all, a lot of ‘LUCK’ to have the
As an embryo practitioner I would have
loved to take the credit for the Sms sent
to me, but I can’t. I have very little influ-
ence and no say to what happens on the
day of the flushing. I can thus confidently
say that the secret to success lies in
management and in good farming prin-
ciples together with the ability to adapt
Dr. Udo H. Mahne, 083 44 33 705
God’s gift to cattlemen BORAN 29