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Some questions require answering before one can judge whether a donor might be considered a good ET Candidate: 1. What is the donor’s age and weight? 2. Is the donor a cow or a heifer? 3. When did the cow last have a calf? 4. Has the donor had any past reproductive problems? 5. When was the donor’s latest heat? 6. Has the donor been flushed before? 7. If she has been flushed, how did she perform? The donor should have calved at least 60 days previous
to starting on a superovulation schedule. This is to allow enough
time for the uterus to return to breeding shape. A quick return
to breeding shape is dependent on the donor receiving her pre-and
post-calving nutritional requirements. A rectal palpation of the
uterus and the ovaries by your veterinarian will also give some
indication of the donor’s condition. The period from calving
until the start of superovulation should never be rushed. Nutrition is an area that should never be overlooked
in any breeding program. Donors and recipients should be on a rising
plane of nutrition for at least 30 days prior to starting the ET
program. This does not mean that a complicated feeding regime is
required. Basically a high-energy ration (barley) plus good hay,
silage, or pasture is sufficient. At some time during the 30 day
period prior to the ET program, donors and recipients should receive
an injection of vitamins A, D, and E, and, if located in a selenium
deficient area, possibly an injection of Selenium. These feeding
guidelines help improve the chances of a successful flush and to
achieve maximum pregnancy rates.
Donors are superovulated with a hormone called Follicle Stimulating Hormone (FSH) which is available in several forms (Folltropin: Bioniche, F-Tropin: Austin, Ovagen: ICP). The treatment starts 9 to 14 days after the last recorded heat. During the schedule of FSH injections the donor should not experience any stressful situations such a feed/water changes nor halter breaking. FSH causes eggs within the ovary to develop to a point where they can be ovulated. The FSH schedule usually involves twice a day injections for four days. On the fifth day of the schedule the donor will show heat. The mature eggs will then ovulate. It is important to observe when the donor is first showing signs of heat and when she is in standing heat. It is advisable to keep the donor with two or three young cows, in an area with good footing, in order to observe a good standing heat. Dairy cows housed in tie stalls should be turned out in a similar manner in order to observe an exact heat time. The donor should be isolated once standing heat is observed in order to avoid injury. The donor should be bred at two different times. The
first breeding (A.I.) should occur 12 hours after the standing heat
is first observed and the second breeding should be done 12 hours
later. Semen used to A.I. the donor should be of good quality and
if there are any doubts about its condition, you should have it
examined by a lab. If this cannot be accomplished then a different
sire of known good fertility should be used. If your intention is
to breed the donor to your herd bull then you should put the donor
with the bull just prior to the expected heat.
4. RECIPIENTS IN THE ET PROGRAM If your intention is to use your own animal as a recipient, then some information on the potential recipient is required: 1. Is the recipient a cow or a heifer? 2. What is the recipient’s age? 3. When did the cow last have a calf (exact date)? 4. When was her last heat? A good recipient, if a cow, is one that has calved
at least 60 days previously. A heifer should weigh a minimum of
800 lbs. and be a minimum of 14-16 months of age. Generally, a two-year-old
heifer with her first calf at her side does not make a good recipient.
A cow that has not previously become pregnant when exposed to a
bull is not desirable as a recipient. Again, as with the donor,
the potential recipient should be on a rising energy ration from
about 30 days prior to calving until she has been used as a recipient.
An injection of vitamins A, D, and E, and selenium should be given
to all recipients prior to synchronizing. Recipient management can
be enhanced with the use of Ivomec (pour on) and by making the most
use of the feed supplied to the recipient.
In order to line up a recipient with the donor’s flush, it is necessary to synchronize the recipient’s heat cycle with that of the donor. To achieve this, two injections of Estrumate (Coopers) or Lutalyse (Upjohn) are given to each recipient, 11 days apart. The use of a Cidr (Bioniche) with either Estrumate or Lutalyse can also be used to synchronize recipients. The schedule of shots is designed in such a way that the recipient will show heat at the same time (or within 24 hours) as the donor. This is necessary so that the uterus of the recipient can accept the day seven embryo flushed from the donor. Prior to coming to the farm we will require a detailed list of the heats observed, including dates and times. Again it is important to avoid having the recipient in stressful situations during the heat detection and transplantation periods. Prior to synchronizing the recipient or superovulating
the donor, a written schedule of events will be sent with any drugs
required to your nearest bus depot for you to pick up.
It has been asked many times if the flush team requires heated facilities to work in. This depends upon the time of year. We prefer to flush the donor inside. The temperature of the room should be approximately 18-20°C (65-70°F). The embryos can be transferred into the recipient either in a barn or outdoors (unless of course a bad storm is in progress). A squeeze chute is required to restrain the donor during flushing and the recipient during embryo transfer. At dairy farms with tie stall barns, the donor can be flushed in the stall. A chute of some sort would still be required for the recipient. In the event that the flush does not produce good
embryos, it is a good idea to have frozen embryos as back up to
put into the recipient. If none are available to you, frozen embryos
(both beef and dairy) can be purchased from the Alta Embryo Group
sales inventory. Arrangement for this should be made prior to the
flush team’s arrival on the farm.
Our flushing team usually consists of one or two people. We arrive at the farm 7 days after the donor was bred. The donor will then be restrained and prepared for flushing. If the veterinarian palpates the ovaries of the donor and feels there has been no response to the FSH, you will be advised and the donor will not be flushed. If the vet does detect a superovulation response the donor will be flushed. Flushing takes approximately 30 minutes, and is carried out non-surgically. It involves passing 500 ml of PBS (salt solution) via a catheter into the donor’s uterus. The fluid is filtered and the embryos are found using a microscope. Once found, the embryos are held in a medium that sustains their viability until it has been decided how they should be used. The embryos recovered are 7 days of age at this time. Unfertilized and degenerate eggs also recovered from the flush are discarded. (Back To Index...)
8. POST-FLUSH TREATMENT OF DONOR After the flush the donor is then allowed to return
to the herd. We ask that you give the donor a shot of Estrumate
or Lutalyse approximately one week after the flush. This ensures
that she does not become pregnant from an embryo not recovered from
the uterus when flushed. If you intend to breed the donor to conceive,
then this can be done on the donor’s first post-flush heat.
Prior to transferring any embryos, the veterinarian will request that all the recipients observed in heat be brought in for palpation. The veterinarian will palpate each recipient’s uterus and ovaries to determine which will make adequate embryo recipients. Approximately 20% of the recipients are rejected due to a poor “CL”. A”CL” is the site on the ovary, where the recipient’s egg ovulated 7 days earlier. Once the number of good candidates is known, the embryos are prepared for transfer. The transfer process, like our flushing process is non-surgical. The transfer procedure involves loading the embryo into a ¼ ml straw and then the straw is loaded into an ET gun. The ET gun is passed into the horn of the uterus that is adjacent to the ovary bearing the CL and the embryo is expelled. If frozen embryos are to be transferred, no additional preparation is required on your part, apart from that previously mentioned. Due to some potential recipients being deemed unsatisfactory by the veterinarian, it is a good idea to start synchronizing 20% more recipients than are actually required. This will ensure that you have enough good recipients to use. Each transfer takes about 3-4 minutes and then the
recipient can be returned to the herd.
As of November 1, 1994 Alta Embryo Group changed its
embryo freezing technique to allow for the “direct transfer”
of frozen embryos. To transfer these frozen embryos into a recipient,
the embryos are removed from the nitrogen tank, air thawed for 10
seconds, immersed in a 35°C water bath for 10 seconds and transferred
into the recipient. Embryos frozen under the previous standard method
using glycerol have to be thawed with the use of a microscope and
cannot be transferred as quickly as embryos frozen with the new
method.
A question often asked is: “What can be expected from the flush and what pregnancy rates might be achieved?” In general, the answer is an average of many collections and transfers. These averages are made up of varying degrees of successes and failures. Reproductively normal cows that have had a calf within the last six months will on average produce 5-6 good embryos per flush. Heifers, as donors, are more unpredictable and will produce on average 3-4 good embryos. Again, I must emphasize that sometimes you can collect much higher numbers but you may also get less. (Keep in mind, these are biological systems that neither you nor we can completely control.) In general: 5 – 10 % of flushes yield no embryos Alta Embryo Group will classify the donors upon entry into excellent, good, average and poor categories. This classification is based on ultrasound scan and previous history. This classification system provides a guideline for client expectations. There are many factors determining why a cow is an excellent or poor donor. Some of these factors are follicle population (# of eggs available on the ovaries for harvest), sires to be used, management, genetics and the donor’s ability to respond to available treatments. Pregnancy rates with fresh embryos should be in the 60-65% range. Frozen embryos should produce on average a 50-55% pregnancy rate. We believe the quality of the recipients and the embryos are the most important factors affecting pregnancy rates. It turns out that pregnancy rates are seldom affected by the weather, handling, or by the personnel involved in transferring the embryos, providing the personnel are qualified to do so. The question often arises as to whether the recipient
affects the genetic make-up of the embryo within her or if the type/breed
of the recipient makes any difference to the embryo. The answer
is simply, ”No.” The recipient’s only contribution
to the embryo is to provide nutrition for growth and, initially
after birth, some immunological defense. The fact that the recipient
can affect the fetus’s immune system is an important factor.
For example, a recipient that tests positive to Leucosis, puts the
fetus she carries at risk of also being Leucosis positive after
birth. The recipient however, does not alter the genetic make-up
of the embryo transferred into her.
12. DONOR COLLECTION AT THE ET CENTRE You may want to consider bringing your donor(s) to our ET facility at Calgary. Currently, there is no health testing required for entry to the ET facility, however it may be beneficial for you to know the Leucosis status of your donor. Our ET centre accepts both negative and positive animals. Every attempt is made to ensure there is no animal to animal transmission of Leucosis. Once your test results come back, the donor along with her registration paper and bloodtype certificate can be brought to the ET centre. The animals are housed in a very professional manner. Calf shelters and creep feeders are made available to all calves that come with the donors. Any animals requiring additional attention (for example, foot trimming or picturing) are promptly looked after. Once the donor is at the ET facility, the rest is up to us. Regular phone calls, faxes, and reports are made to you to keep you as current as possible concerning the activities of your donor. If you decide to keep your donor at home and administer the FSH injections yourself, later bringing your donor in the ET Center for flushing, we can accommodate you. (Back To Index...)
13. ALTA EMBRYO GROUP RECIPIENTS If you want your embryos transferred into an Alta Embryo recipient it is necessary to discuss your needs with our Recipient Program Coordinator. The type of recipient available depends on the time of year and on recipient demand. Dairy heifers are available throughout the year. Beef heifers are available from about April 1st to June 30th. Advance arrangements are required to ensure an adequate supply of cows. All recipients made available to our clients are tested negative for Leucosis prior to us purchasing them. Once the recipient is determined 60 days pregnant
we will telephone you and ask that arrangements be made for her
to be picked up. At the time of the recipient’s 60-day pregnancy
exam, the fetus can be examined by ultrasound to determine sex.
14. DOCUMENTATION OF ET PREGNANCIES AND CALVES Any pregnancies produced for you by Alta Embryo Group whether at your farm or at our ET centre will be documented on official ET forms and sent to you. These forms must be kept by you and sent to your breed association with the application for calf registration. (Back To Index...) All embryo donors must have either a recorded bloodtype
or DNA profile. The same is true for the sire of embryos. Most A.I.
Sires are bloodtyped at the time of semen collection. If you use
natural service on your donor, then the bull used must also be bloodtyped
or DNA profiled. At this time bloodtyping is completed by the Saskatchewan
Research Council in Saskatoon or Maxxam Labs. You may either have
a blood/hair sample drawn at home and sent in or it can be done
at the ET Centre. Blood/hair samples must be drawn from ET calves
and a parentage verification test performed. Most breed associations
now require a DNA record of the donor dam and sire instead of a
bloodtype. Embryo sexing is currently done at the ET Centre.
This allows for a very clean and precise determination of the embryo’s
sex. A biopsy (5-10 cells) is taken from the embryo and this biopsy
is examined to determine the presence of the Y (male) chromosome.
In most cases, a determination can be made but occasionally a clear
indication as to the sex is not evident. We do not charge for cases
where the sex cannot be determined. Because a part of the embryo
is removed, sexed embryos give a slightly lower pregnancy rate than
whole embryos. This is compensated through the production of a calf
of a desired sex. 17. SPECIAL
PROGRAMS Our embryo production team is a certified member of the Canadian Embryo Transfer Association. Embryos can be certified for export in a timely manner. Our qualified shipping department, both domestically and internationally, handles embryo shipments. If you would like to discuss a possible on-farm collection or want to bring in your donor, please call us and we will work out the details. If you are interested in some of our more specialized programs feel free to contact us and we will discuss a program that makes economic sense and augments your breeding program. Alta Embryo Group Ltd.
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