Some examples of substrates used (also known as chromogens) are AEC (3-Amino-9-EthylCarbazole), or DAB (3,3'-Diaminobenzidine). Use of one of these reagents after exposure to the necessary enzyme (e.g., horseradish peroxidase conjugated to an antibody reagent) produces a positive immunoreaction product.
1. Know When You Ovulate after Childbirth. Most women experience an extended period of bleeding immediately after giving birth. The bleeding will get lighter and lighter, lasting about six weeks. It is extremely unlikely that a woman will become pregnant during this time, although it is not impossible.
How long it takes for a cow to give birth really depends on her body condition, her experience, how big the calf is inside her, environmental conditions, and whether the calf is presenting normally or not. As a result there really is no set-in-stone time it takes for a cow to give birth. For experienced cows, it's only a matter of 5 to 6 hours until the calf arrives. For a heifer, it can be a few to a number of hours longer. See the related question below for a similar answer. If, by any chance, you are asking how long a cow is pregnant in days, the average is around 285 days long. Please see the related question on the length of gestation below for a more detailed answer. Karin L.