Determination of pregnancy status in cattle and sheep
A method and kit for determining whether an animal is not pregnant, or is pregnant following a breeding. The level of expression of a pregnancy induced protein is determined in an animal for which pregnancy status information is desired and the level is compared to that of the level in animals that are not pregnant.
1. A method for determining non-pregnancy status in an animal selected from the group consisting of cattle and sheep, comprising determining the level of extra-uterine expression of a pregnancy-induced protein selected from the group consisting of Mx protein and ubiquitin cross-reactive protein in blood collected from the animal during the period 15 to 27 days following breeding of a ewe or 18 to 30 days following breeding of a cow and comparing the level of expression of said protein in the animal to that of a non-pregnant female animal of the same species, wherein an absence of increase in the level of the expression of the protein in the animal compared to that of the non-pregnant animal indicates that the animal is not pregnant.
2. The method of claim 1 wherein the protein is Mx protein.
3. The method of claim 1 wherein the pregnancy-induced protein is ubiquitin cross-reactive protein.
4. The method of claim 1 wherein the level of expression of the protein is determined by determining the level of mRNA coding for the protein.
5. The method of claim 4 wherein the determination of mRNA is by Northern blot analysis, slot-blot analysis, or polymerase chain reaction.
6. The method of claim 1 wherein the determination of the level of production of the protein is by evaluating the binding of an antibody to the protein or by an assay based on a function of the protein.
7. The method of claim 1 wherein the level of production of the protein is detected by a colorimetric assay.
8. The method of claim 1 wherein the level of expression of the protein is determined by determining the expression of the protein in a peripheral blood mononuclear cell of the animal.
9. The method of claim 1 wherein the comparison is by side-by-side comparison of the level of expression of the protein in the animal and the level of expression in an animal known to be not pregnant.
10. The method of claim 1 wherein the comparing is by using an historical control.
11. The method of claim 1 which is performed during the period between 18 and 21 days after breeding of the ewe or cow.