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Embryo Flushings_ a matter of management - EMBRYO FLUSHINGS_

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Embryo Flushings_ a matter of management - EMBRYO FLUSHINGS_ Powered By Docstoc
					  EMBRYO FLUSHINGS,
                           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?




F
          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
                                                                                 ovulation hormone.
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
                                                                                 activate.
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
                                                                            your farm
 • 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
                  Recipient selection.
                                                                          • 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
                                                              time.
                                                              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
                                                                                  Flushing filter

                                                                         Deficiencies present themselves as a high
                                                                        percentage unfertilized or dead embryos
                                                                        retrieved.
                                                                        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:
                  Balanced nutrition
                                                                        • 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
                                                                          a cow.
 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
and cold.
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.
           CONCLUSION:
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
climate constant.
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
and persist.
Dr. Udo H. Mahne, 083 44 33 705
www.embryo-life.com




                                                God’s gift to cattlemen BORAN   29

				
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