1412 N ROBERTS RD
DALLAS COUNTY, FERRIS TX 75125-8688
EUNICE GERLOFF 972-842-3697
egtxranch@msn.com
CATTLE IMPROVEMENT
BREEDING PROGRAM USING ARTIFICIAL INSEMINATION
AND
EMBRYO TRANSFER
SYNCHRONIZED CATTLE A.I. BREEDING PLAN
ESTABLISH NUTRITION AND MANAGEMENT PROGRAM FOR HERD INCLUDING ESSENTIAL VITAMIN/MINERAL SUPPLEMENTS.
PREPARE STURDY PENS, WORKING CHUTE, AND HEADGATE.
CONSULT VETERINARIAN ABOUT TIMELY VACCINATIONS, SUCH AS BRUCELLOSIS, 5-WAY LEPTO, IBR-BVD-BRSV, 7-WAY BLACKLEG WITH H.SOMNUS PLUS BIANNUAL PARASITE CONTROL. (JANUARY/JULY)
CHECK CONDITION AND REPRODUCTIVE STATUS OF EACH COW. IDENTIFY GROUP OF OPEN CATTLE TO BE BRED.
ORDER PREFERRED BULL UNITS FROM SEMEN COMPANY.
OBTAIN HEAT-INDUCING (PROSTAGLANDIN) HORMONES FROM VETERINARIAN SUCH AS LUTALYSE OR ESTRUMATE
____________ FIRST HORMONE INJECTION DATE 17 DAYS PRIOR TO BREEDING.
____________ SECOND HORMONE INJECTION 14 DAYS AFTER FIRST INJECTION.
____________ BREEDING DATE THAT IS APPROXIMATELY 285 DAYS PREVIOUS TO
____________ TARGETED CALVING DATE.
ESTRUS (STANDING HEAT) SHOULD OCCUR ON CHOSEN BREEDING DATE.
RECORD TIME OF START OF STANDING HEAT FOR EACH ANIMAL.
Observe cows for 20-30 minutes early in the morning and late in the evening. Make one person responsible for heat detection.
The method that generally works best is to move around in the pen for 10 to 15 minutes or more while gently moving the cattle around and chasing those up that are lying down. Cows are less likely to display standing heat while eating. Detection cannot be done properly while sitting on the fence although this may be an initial step. Those cows in estrus stand still when mounted by others. Suspicious signs include ruffled rump hair, restlessness, bawling, walking the fence, nudging, mounting, sniffing, tail raising, clear mucous from the vulva and a pink swollen vulva.
Contact A.I. technician when standing heat is first observed. Inseminate cattle approximately 14 to 18 hours after the beginning of standing heat.
IF A COW IS SELECTED AS A RECIPIENT FOR AN EMBRYO, INSTEAD OF BREEDING THE COW, MAKE NOTE OF HEAT TIME AND ARRANGE FOR EMBRYO TRANSFER SEVEN DAYS LATER.
BOVINE EMBRYO TRANSFER
The nonsurgical procedure of embryo transfer involves removing a seven-day old embryo from a donor cow and transferring it to a rcipient cow that may or may not, be the same breed. The donor is usually artificially inseminated using sperm from the best bull available. The resulting offspring will have the superior genetics of the donor and the bull used. The schedule includes the use of hormones to synchronize the estrus dates of the donor and recipients.
Past experience has proven other "distinct advantages to ET:,
1. More progeny could be obtained from selected females.
2. Calves could be obtained from cows too old to sustain a pregnancy.
3 Genetics could be shipped abroad in nitrogen tanks instead of cattle in jets with less chance of disease problems.
The basic disadvantge to ET for most breeders was the cost of the process. The shots to induce superovulation, the specialized skill needed to harvest embryos, and the uncertainty of the number of viable embryos made the process expensive and high risk" (Mansfield 126).
"Fertilized ova are removed by surgery, or by flushing the reproductive tract, after conception but before implantation. The ova are held and transprorted in a liquid medium, then deposited into the uterus of the host female. Techniques vary among species and also among scientists or commercial installations. For efficiency and high chances of successful implantation, superovulation of the donor female is usually done by hormone treatment to increase ova numbers" (Acker).
The bottles containing hormones should be refrigerated and injections should be given with sterile disposable syringes and 20 guage needles. Extra precautions should be taken by pregnant women to avoid any contact with these hormones. If they are administered by a non-pregnant female, rubber gloves should be worn to help prevent changes in personal menstrual cycle. The follicle stimulating hormone is injected into the donor for four days starting the tenth day after observing standing heat. On day two of the regimen prostaglandin is injected into the recipients. Prostaglandin is injected into the donor on day four of the regimen.
"Following superovulation treatment . . . the time when the donor is first observed in standing estrus is the reference point for insemination" (Elsden and Seidel 7).
Breeding is usually most effective at 18 and 24 hours.
"Age of the ovum at time of fertilization may influence maintenance of pregnancy, in that older ova are less likely to survive after fertilization. There is also evidence that embros resulting from older sperm are less likely to survive" (Acker).
For ET work, cows should be in a gaining state of body condition but not fat. A veterinarian should be consulted for a regular herd reproductive and nutritional health program.
In their booklet, Elsden and Seidel relate that "For commercial purposes, attempts are made to recover bovine embryos six to nine days after estrus . . . An epidural injection of 5ml of 2% procaine is given.
A technician inserts one arm in the rectum to estimate numbers of corpus luteum and follicles and sizes of ovaries.
A two-way Foley catheter with a stiffening rod of stainless steel inside is inserted gently into the vagina and on into the lumen of the cervix. Using the so-called "body flush", the balloon of the Foley catheter is inflated in the body of the uterus. The catheter is then pulled back toward the cervix, and the uterus is allowed to fill with fluid. Approximately 2 liters of medium (a modified Dulbecco's phosphate buffered saline plus 1% bovine serum) are . . . attached to the inflow tube of the Foley catheter with a Y connector. A piece of tygon tubing is connected to the outflow tube of the Foley catheter with the Y connector, and the other end is held at the top of a 1,000ml cylinder or filter. The drainage tube is clamped and the uterine horns are filled with medium. The technician agitates the uterus to dislodge ova held by endometrial folds. Then the drainage tube is opened and a clamp is placed on the inflow tube. Medium with ova will flow out. Once the initial rush of fluid is over, the remaining medium is massaged out.
Location, identification, isolation, manipulation and classification of unfertilized ova and embryos require considerable practice. From the moment they are recovered, embryos must be handled with sterile techniques. As soon as possible they should be located under a dissecting microscope, washed three times in sterile medium, and then evaluated and stored until transfer. Embryos recovered on days 5 or 6 should be at the MORULAE stage of development and those recovered on day 7 or later should be at the BLASTOCYST stage. Embryos should be evaluated so that appropriate recipients can be selected.
In general, the best embryos should be transfered to the best recipients. In addition the ageof the embryo can be matched to some extent to the uterine environment of the recipient.
"Transfers can be made reasonably successful only if the prededing estrus in the donor and recipient occurred within two days of each other. Experimentally it has been shown that results are:
(1) Best when donors and recipients are exactly synchronous,
(2)Reasonable when they are out of phase by +or- 1 day and
(3)Too poor to be useable when they differ by +or- 2 days" (Morrow 85).
Elsden and Seidel explain that an embryo is aspirated into a quarter milliliter French straw. An air bubble separates the medium containing the embryo from the remaining medium. Once through the cervix of the recipient, the transferring straw gun, containing the embryo, is directed to the horn ipsilateral to the corpus luteum. The horn is raised and straightened in front of the tip of the straw gun before it is gently pushed up the horn. Once resistence is met, the embryo is expelled, and the straw gun is removed.
Recipients are observed closely for estrus following transfer, and pregnancy is diagnosed by rectal palpation 50 to 70 days after the pre-transfer estrus. Several studies have shown that palpation for a pregnancy prior to 50 days can cause abortion . . . Embryo transfer embodies the saying that a chain is only as strong as its weakest link. None of the techniques is difficult, but each is a potential sourcefor failure. Thus, the single most important factor influencing success rate is competent and conscientious personnel following a smooth routine".
Works Cited
Acker, Duane. ANIMAL SCIENCE AND INDUSTRY. Englewood Cliffs: Prentice-Hall, 1983
Elsden, R.P. and Seidel, G.E. PROCEDURES FOR RECOVERY, BISECTION, FREEZING AND TRANSFER OF BOVINE EMBRYOS. Fort Collins: Colorado State University, 1985
Mansfield, Richard H. PROGRESS OF THE BREED. Sandy Creek: Holstein-Friesian World, 1985.
Morrow, David A. CURRENT THERAPY IN THERIOGENOLOGY: DIAGNOSIS, TREATMENT, AND PREVENTION OF REPRODUCTIVE DISEASES IN ANIMALS. Philadelphia: W.B. Saunders, 1980.
3 Genetics could be shipped abroad in nitrogen tanks instead of cattle in jets with less chance of disease problems.
The basic disadvantge to ET for most breeders was the cost of the process. The shots to induce superovulation, the specialized skill needed to harvest embryos, and the uncertainty of the number of viable embryos made the process expensive and high risk" (Mansfield 126).
"Fertilized ova are removed by surgery, or by flushing the reproductive tract, after conception but before implantation. The ova are held and transprorted in a liquid medium, then deposited into the uterus of the host female. Techniques vary among species and also among scientists or commercial installations. For efficiency and high chances of successful implantation, superovulation of the donor female is usually done by hormone treatment to increase ova numbers" (Acker).
The bottles containing hormones should be refrigerated and injections should be given with sterile disposable syringes and 20 guage needles. Extra precautions should be taken by pregnant women to avoid any contact with these hormones. If they are administered by a non-pregnant female, rubber gloves should be worn to help prevent changes in personal menstrual cycle. The follicle stimulating hormone is injected into the donor for four days starting the tenth day after observing standing heat. On day two of the regimen prostaglandin is injected into the recipients. Prostaglandin is injected into the donor on day four of the regimen.
"Following superovulation treatment . . . the time when the donor is first observed in standing estrus is the reference point for insemination" (Elsden and Seidel 7).
Breeding is usually most effective at 18 and 24 hours.
"Age of the ovum at time of fertilization may influence maintenance of pregnancy, in that older ova are less likely to survive after fertilization. There is also evidence that embros resulting from older sperm are less likely to survive" (Acker).
For ET work, cows should be in a gaining state of body condition but not fat. A veterinarian should be consulted for a regular herd reproductive and nutritional health program.
In their booklet, Elsden and Seidel relate that "For commercial purposes, attempts are made to recover bovine embryos six to nine days after estrus . . . An epidural injection of 5ml of 2% procaine is given.
A technician inserts one arm in the rectum to estimate numbers of corpus luteum and follicles and sizes of ovaries.
A two-way Foley catheter with a stiffening rod of stainless steel inside is inserted gently into the vagina and on into the lumen of the cervix. Using the so-called "body flush", the balloon of the Foley catheter is inflated in the body of the uterus. The catheter is then pulled back toward the cervix, and the uterus is allowed to fill with fluid. Approximately 2 liters of medium (a modified Dulbecco's phosphate buffered saline plus 1% bovine serum) are . . . attached to the inflow tube of the Foley catheter with a Y connector. A piece of tygon tubing is connected to the outflow tube of the Foley catheter with the Y connector, and the other end is held at the top of a 1,000ml cylinder or filter. The drainage tube is clamped and the uterine horns are filled with medium. The technician agitates the uterus to dislodge ova held by endometrial folds. Then the drainage tube is opened and a clamp is placed on the inflow tube. Medium with ova will flow out. Once the initial rush of fluid is over, the remaining medium is massaged out.
Location, identification, isolation, manipulation and classification of unfertilized ova and embryos require considerable practice. From the moment they are recovered, embryos must be handled with sterile techniques. As soon as possible they should be located under a dissecting microscope, washed three times in sterile medium, and then evaluated and stored until transfer. Embryos recovered on days 5 or 6 should be at the MORULAE stage of development and those recovered on day 7 or later should be at the BLASTOCYST stage. Embryos should be evaluated so that appropriate recipients can be selected.
In general, the best embryos should be transfered to the best recipients. In addition the ageof the embryo can be matched to some extent to the uterine environment of the recipient.
"Transfers can be made reasonably successful only if the prededing estrus in the donor and recipient occurred within two days of each other. Experimentally it has been shown that results are:
(1) Best when donors and recipients are exactly synchronous,
(2)Reasonable when they are out of phase by +or- 1 day and
(3)Too poor to be useable when they differ by +or- 2 days" (Morrow 85).
Elsden and Seidel explain that an embryo is aspirated into a quarter milliliter French straw. An air bubble separates the medium containing the embryo from the remaining medium. Once through the cervix of the recipient, the transferring straw gun, containing the embryo, is directed to the horn ipsilateral to the corpus luteum. The horn is raised and straightened in front of the tip of the straw gun before it is gently pushed up the horn. Once resistence is met, the embryo is expelled, and the straw gun is removed.
Recipients are observed closely for estrus following transfer, and pregnancy is diagnosed by rectal palpation 50 to 70 days after the pre-transfer estrus. Several studies have shown that palpation for a pregnancy prior to 50 days can cause abortion . . . Embryo transfer embodies the saying that a chain is only as strong as its weakest link. None of the techniques is difficult, but each is a potential sourcefor failure. Thus, the single most important factor influencing success rate is competent and conscientious personnel following a smooth routine".
Works Cited
Acker, Duane. ANIMAL SCIENCE AND INDUSTRY. Englewood Cliffs: Prentice-Hall, 1983
Elsden, R.P. and Seidel, G.E. PROCEDURES FOR RECOVERY, BISECTION, FREEZING AND TRANSFER OF BOVINE EMBRYOS. Fort Collins: Colorado State University, 1985
Mansfield, Richard H. PROGRESS OF THE BREED. Sandy Creek: Holstein-Friesian World, 1985.
Morrow, David A. CURRENT THERAPY IN THERIOGENOLOGY: DIAGNOSIS, TREATMENT, AND PREVENTION OF REPRODUCTIVE DISEASES IN ANIMALS. Philadelphia: W.B. Saunders, 1980.