Biomarkers For Pregnancy In Dairy Cattle
NETHERLANDS - Proteomics is an ideal basis for an analysis of all the proteins in a biological sample. Some proteins or the profile of a set of proteins present in the milk of lactating cows may be related to the pregnancy status of dairy cows. If so, these protein profiles can be used as predictors in a pregnancy test for dairy cattle that can be performed using a drop of milk. These tests could prove to be valuable tools for management looking to decrease the calving interval. In this regard, important research questions include the following: Is a pregnancy-specific protein profile present in milk samples of pregnant dairy cows, and how does this profile vary between animals and over time? These questions were addressed in a pilot study by the Animal Breeding and Genomics Centre (ABGC).
The results show that the concentrations of some milk proteins differ between pregnant and non-pregnant cows. Those differences can be detected as early as day 21 after insemination. However, there is great variation in the concentration of these proteins between individual cows. Based on the concentration of one single protein, sensitivity and specificity of a maximum of 93 per cent and 61 per cent respectively were obtained in this experiment. Using combinations of multiple proteins did not improve sensitivity or specificity. This indicates that the discriminating power of the identified proteins is still low, especially for classifying non-pregnant cows. The current data are therefore not yet sufficient to develop a reliable pregnancy test.
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