Bovine layout rev. 6/03

Bovine Layout rev. 6/03 6/2/03 1:32 PM Page 1 open cow. (Light blue or bright blue test result.) Pregnant cowscontinue to produce progesterone throughout gestation (white test The stress of milk production can effect the cyclic activity. Also, Milk samples should be collected into a clean container. Samples of Progesterone, a natural hormone that circulates in the cow’s the hormonal activity after calving can reduce the intensity of estrus foremilk or from the milk jug are best. The last milk can be used, but blood and can be found in the milk, is produced by the corpus behavior. Therefore, it is sometimes difficult to observe heat. If a it is less preferred. Initial strippings should not be used. Label the Two important uses for the TARGET test are when a cow is sus- luteum (CL) and fluctuates during a normal estrous cycle. Milk milk sample taken on the suspected day of estrus gives a bright samples with the cow number, sampling date, and cycle day.
pected to be in heat to confirm estrus or about 20 days after or blood progesterone levels accurately reflect the different blue result, this confirms that the cow is in heat and ovulation is insemination to check if the cow is open. At 20 days after insemi- If a milk sample is not tested within 30 min., it should be stored in the nation progesterone levels will be low (bright blue) if the cow is refrigeratior- do not freeze. If a milk sample is to be tested more than open, or high (white) if the cow is pregnant. The open cow can The various stages of the estrous cycle are: 6 hrs later, add one drop of milk preservative (ormilk preservative Estrus (or standing heat) Day 0: The cycle begins. The nor- tablet) to each 10 mls of milk immediately after collection.
mal cycle is about 21 days. Each heat (estrus) lasts 6-18 hours.
• TARGET can be useful in diagnosing cysts. A normally cycling When used in this way TARGET can help improve breeding effi- Progesterone levels are lowest during this time (see figure). The cow will show one white and one blue result for two samples taken Allow samples and all kt reagents to come to room temperature before starting test (2-24 hrs). Use a timer while performing the test.
Metestrus (Day 1-7): Ovulation occurs after estrus; the CL • If the results for two samples taken 7 days apart for a nonpreg- forms on the ovary and begins producing progesterone. The nant cow are both white, this indicates a luteal cyst. Cows with progesterone levels begin to rise. The test result is light blue.
Prostaglandin is used when the cow has a functional corpus luteal cysts can be treated with prostaglandin. The treatment was Diestrus (Day 8-16): The progesterone concentration is luteum (progesterone level is high) in order to induce heat (low Store this kit in the refrigerator when not in use. Do not freeze.
effective, if a TARGET test taken 2-4 days after treatment shows very high during this time. The test result is white. bright blue results. This means the cow is now in heat and can be Proestrus (Day 17 to the onset of the next estrus): The CL Always reseal the plastic bag after removing a test cup.
In order for prostaglandin to be most effective, it is important to begins to regress and the progesterone levels begin to drop.
know where the cow is in her cycle at the time of the injection in Timing during Step 2 (Time of the enzyme) • Cows that have consistently low progesterone results (bright blue) for two samples taken 7 days apart are likely to have a Progesterone levels during the reproductive cycle
For an unbred cow, a white result indicates that the cow is in follicular cyst. Cows with follicular cysts can be treated with GnRH In normally cycling cows a low progesterone level indicates an diestrus or may have a persist corpus luteum. Prostaglandin may or hCG and bred when they come into heat. The therapy was Do not exchange test cups or reagents between different kits.
be used at the time of a white result to bring her into heat. About effective, if a white result (high progesterone) is obtained for a sam- 72 hours after prostaglandin administration, a progesterone test ple taken 10 days after treatment for a follicular cyst .
will confirm heat (bright blue result). If the result is not bright blue, the CL has not fully regressed and could recover. Another treat- ment of prostaglandin is advisable in this case.
Progesterone testing of the recipient cow is an important step in an For a cow that has been bred, a white result 20 days after embryo transfer protocol. It is recommended that the proges- insemination can indicate pregnancy. Prostaglandin should NOT terone level in the recipient be greater than 3 ng/ml for the best be used at this time, since it lowers progesterone and will cause an 0 4 8 12 16 20 24 28 32 36 40 44 Days Bovine Layout rev. 6/03 6/2/03 1:32 PM Page 2 Color And
Progesterone
Interpretation
Take the kit out of the refrigerator at least 2 hours before using it in order to allow the kit to come to room temperature. No progesterone is present and there is NO functional CL. (It is possible to leave the kit at room temperature overnight, Bright blue means standing heat in normally cycling cows .
In the prepubertal hefer or postpartum cow, a bright blue result can Bright Blue
0 - 1 ng/ml
A bright blue test result for each of 2 samples taken 7 days apart strongly indicates the presence of a follicular cyst.
1 Add 4 drops of milk or serum or plasma to Progesterone is either rising after heat or falling (approaching heat).
See Figure. A second test should be run in 2 days.
If a test is repeated 2-3 days later, the results will be either bright blue (heat) or white (high progesterone).
• This kit is the most accurate method for determining the In embryo transfer the recipient should show a light blue test resultwhen an embryo is transferred.
presence of a corpus luteum (CL) and for determining if it Light Blue
1 - 5 ng/ml
• By identifying open cows earlier this kit will reduce the Wait for liquid to drain into cup. REPEAT this step 1X or A white result indicates a high progesterone level and a functional • Recommended for use in embryo transfer programs to * Throw out any unused solution in the blue mixing bottle after 30 min- utes, since the substrate decomposes. Save blue mixing bottle for A) A white result indicates pregnancy if the test was taken 19 to 23 days after breeding or that the cow is in mid cycle.
B) A white test result for each of 2 samples taken 7 days apart strongly indicates the presence of a luteal cyst.
> 5 ng/ml

Source: http://targetvet.com/images/pdf/Bovine_Instr.pdf