Progesterone test
Progesterone tests are an important source of information for evaluating the cycle of animals in order to achieve better results with artificial insemination of the animals.
Beef
In times of falling pregnancy rates in high-yielding cattle, the progesterone test in domestic cattle is becoming increasingly important as a management tool to increase the fertility of a herd. The concentration of the pregnancy-preserving hormone progesterone in blood serum or preferably milk is measured in order to be able to draw conclusions about the course of the cycle, non-pregnancies and fake oestrus in cows: the knowledge gained thereby completes conventional oestrus observation. In this way, calving intervals can be shortened, problem animals can be identified and herd fertility can be improved as a whole.
Cycle course
As a rule, an oestrus cycle in cattle lasts 21 (18 to 23) days. When a cow is in heat, there is one on the ovary of this animal
Primary follicle matured. This produces the oestrus hormones (estrogens) that trigger the external signs of oestrus. After ovulation (ovulation), a corpus luteum grows in the remaining follicular cavity, which forms the progesterone. The more the corpus luteum grows, the more progesterone is produced. The progesterone blocks the release of other hormones (FSH and LH) that normally start a new cycle. If fertilization is unsuccessful, the corpus luteum regresses from day 18, whereupon the progesterone level in the blood drops until the corpus luteum has completely disappeared and no more progesterone is formed. Only then can a new follicle develop and the cycle begins again. If, on the other hand, fertilization is successful, the progesterone level remains at its high level. The cow is now pregnant and no longer comes into heat.
Statements by means of a progesterone test
Cattle control
As a rule, the progesterone test is carried out on day 19/20/21 to identify those animals in which insemination was unsuccessful: if the progesterone level is low, pregnancy can be ruled out with 100% certainty and insemination as early as the next ovulation can be performed without missing another cycle. In this way, high financial losses, which are estimated at 3 euros per animal and day of extended intercalation time, can be avoided.
False heat control
If a cow unexpectedly shows oestrus symptoms, i.e. outside the expected time, but at the same time shows a high progesterone level, a false oestrus is given and insemination would be superfluous.
Control of the cattle cycle
In cows whose cycle course is unclear (e.g. problem animals, first calves), an analysis of the progesterone level can provide information about the normal or abnormal cycle. Two to three tests every few days can be used to determine at which point in the cycle the cow is. The progesterone test can also provide clues about animal health problems such as ovarian cysts or persistent corpuscles.
Optimization of synchronization programs
As part of synchronization programs, prostaglandin (PGF 2α) is administered, among other things, in order to break down a corpus luteum and thus initiate follicular formation and oestrus. The use of prostaglandin is only promising if the corpus luteum is active. By using a progesterone test, the presence of an active corpus luteum can be checked and thus costs for an unsuccessful hormone treatment can be saved.
Checking recipient animals in the context of embryo transfer
Embryo Transfer (ET) involves transferring embryos to recipient animals (receptors) that are in the appropriate cycle stage, i.e. H. they must have an active corpus luteum. A correspondingly high progesterone level underpins the suitability of receptors. Receptors with unclear palpatory findings are also quite suitable if the progesterone level is high. Conversely, transmission to a recipient animal, in which the embryo cannot grow due to low progesterone levels, is prevented.
Analyzers
Progesterone tests have been used on farms for years to detect the pregnancy protection hormone progesterone in milk or blood serum from cattle. Semi-quantitative rapid tests offered include Hormonost® from Biolab GmbH, Unterschleissheim, eProCheck® from FrimTec, Oberostendorf or the Bovine Progesterone Kit from Biometallics Inc., Princeton, USA. The commercial test systems work on the basis of ELISA tests; only small amounts such as 2 drops of milk or blood serum are necessary to achieve a result.
dog
The decisive point in the bitch's reproduction management is the determination of the optimal time for artificial insemination or mating. Vaginal smears and vaginoscopy are used as indicators for this, but the bitch's progesterone level should also be used in optimal reproductive management.
Applications
- Determination of the ovulation day
- Limitation of the optimal covering / insemination period
- Verification of the normal start of labor or assistance with the decision to perform a caesarean section
credentials
- Berthold Achler et al. (Ed.): Cattle insemination with success. Handbook for self-inseminators . Published by Top agrar , the magazine for modern agriculture. Landwirtschaftsverlag, Münster 2002, ISBN 3-7843-3127-0 , ( Top-agrar-Fachbuch ).
- Heinrich Bollwein: Does the early pregnancy check pay off? . In: Milchrind 3, 2008, ISSN 0941-1348 .