Hormones Part One

Chores went as usual and the unique aspect of the day was when the CIDRs arrived so a handful of jersey heifers that are of breeding age got implanted with them. This got me thinking, I remember creating a post about the CIDRs in the past but I do not think that I went into detail about the specific hormones related to estrous and pregnancy so I'm going to change that! CIDR can be pronounced as seeder and this device uses the hormone progesterone to help farmers synchronize estrous cycles for breeding purposes. Today and tomorrow I want to discuss four important hormones related to the estrous cycle of cows. For now, I want to start with progesterone and luteinizing hormone.

I have already described the primary function of progesterone above in my introduction. Progesterone is a hormone that is secreted by a temporary organ (sometimes referred to as a gland) called the corpus luteum. A corpus lutetium is found on the ovary only after the complete maturation and rupture of a follicle. Progesterone influences the cells lining the uterus to prepare for pregnancy, making it the perfect environment for a developing embryo. 

When I mention that the follicle ruptures, this process is more simply known as ovulation! Ovulation can be thought of in a more biochemical light simply by considering how the hormone LH (luteinizing hormone) stimulates the release of a mature follicle. LH is secreted from the anterior pituitary gland (roughly located at the base of the brain) and without it ovulation would not proceed. Without ovulation, the formation of a corpus luteum will not ensue and no progesterone will be released.   

If you are interested in learning more, check out this link here as it provides a further detailed explanation to ovulation and the purpose of a corpus luteum. Below is a figure from the linked source which shows what the ovary would look like during each stage of follicular (egg) development until eventual ovulation and formation of a corpus luteum. 

Today we shipped 4,904 gallons of milk

Today we had _ new calves.