Thursday, May 24, 2012

The start of 2012 Breeding Season

Last Friday morning at 6:45AM Jake, Calvin and his Dad put a CIDR in each of the 125 cows and gave them all a shot of GnRH (Gonadotropin Releasing Hormone).  GnRH is naturally released at the beginning of the cyle by the part of the brain, known as the hypothalamus and the pituitary gland to produce two hormones the Follicle Stimulating Hormone (FSH) and Luteinizing Hormone (LH).  This began the Synhronization of estrous in the Wolfinger herd. 

** Side Note** The female birth control product called IUD . . . trade name Mirena works exactly like a CIDR for cows.  A CIDR is a birth control product that will not allow the cow to cycle until it is removed . . . exactly like the female IUD. - Thank you Zinpro representative Micah Boysel

This process  involves manipulating the estrous cycle of beef females so they can be bred at approximately the same time. By manipulating the heat cycle, causing the cows to release eggs at the same time and be bred at the same time and then eventually calving at the same time. Calving all the cows at approximately the same time allows us to keep a close eye on the calving mamas.  This also "should" in the perfect world allow us to ship consistent loads of calves. 

Why combine the GnRH with a CIDR?  If you just put a CIDR in a cow she will most likely cycle.  Giving the shot of GNRH when you put the CIDR in,  will cause the follicle to ovulate and that will form the first CL or corpus luteum.  The CIDR works mostly on the uterus, preparing it for pregnancy.

This is a used Cidr, and yes it goes there.  In the second hole in the back end of all cows and heifers that we want to synchronize. This plastic device has progesterone in it, something that naturally occurs in cows from the CL.

When they were finished Jake and Calvin completed some last minute wedding tasks.

Yesterday we left Jaelin's preschool graduation to pull the breeding box over to Fairfield County and pull the CIDRS that have been giving continual progesterone to the cows and heifers.  

When the CIDR is pulled and an injection of Lutalyse® (a prostaglandin, or PGF) is given it drops the female’s progesterone level that results in the rupture of the follicle and estrus and ovulation to begin, also known as the release of the egg.  

I know this is so exciting you want to know what is happening with these cows as we speak.  Because even though these cows were all treated the same, they still will ovulate at slightly different times.  There are follicles bursting all over the pasture (wouldn't it be cool if you could see that) and then the LH causes the follicle to form a solid dark red or yellow structure called a yellow body or corpus luteum (CL).  The progesterone released by the yellow body will then prepare the body for a pregnancy in case the egg is fertilized.  If the egg is not fertilized the cycle starts over.  Lets hope  all the eggs are fertilized in this case.

We started at 1:20 PM on Wednesday.  Therefore on Saturday morning the cows will need to be bred starting at 7:20AM.

Timing on this process is Everything.

Stay tuned for the artificial insemination process . . .

No comments:

Post a Comment