No Bull Pt. 2
Things did not go as planned this weekend. I told you that we were going to try to brand on Saturday, but the rain came. Which is wonderful for the grass and the oats and alfalfa that were just planted, but not good for our branding plans. So we were going to delay until Monday, but it looked like the weather would clear so we moved it up to today. We gathered and branded today and, thankfully, our neighbors were nice enough to work with us on scheduling and come help on Mother's Day. By the way, Happy Mother's Day to all of you mothers out there. I hope it was wonderful.
Last week I told you that we were going to talk about the process of AI and I will. Sorry if it seems kind of brief, but I am a little worn our from the days events. The process of AI is fairly straightforward so it shouldn't take long. We will start with the process of synchronizing and move on from there.
There are a few ways to synchronize the estrous cycles of cattle, but the one we use is based around feeding MGA. MGA is melengenstrol acetate, a progestin formula that works like "the pill." It simply prevents cycling from an oral source. CiDRs (controlled internal drug release) are another option that is in the form of an IUD. We use CiDRs when AIing our older cows because they are on pasture and we don't have an easy way to feed them MGA. When using MGA, we prevent them from cycling for 14 days (the normal estrous cycle takes 21 days) and then stop feeding MGA for 19 days allowing them almost a full cycle. On day 19, we give them a shot of prostaglandin (PG). PG helps to bring the heifers into heat.
At the same time we give the shot, we put stickers on them. The stickers are brightly colored and covered in silver much like a scratch-off ticket. When cows are coming into heat, other cows will "mount" them. When a heifer stands (doesn't try to get away from being mounted), they are in heat. This mounting rubs the silver off of the sticker so that we can see which heifers need to be bred. We also try to look at them quite often and catch any the the stickers may not work on. Heat detection is done for three days with heifers being AIed through that time. At the end of three days, we give any heifers that have not shown heat a shot of gonadotropin releasing hormone (GnRH). GnRH causes ovulation and we then breed these heifers at that time. For these "time bred" heifers we do have lower conception.
The actual insemination requires a pipet to be loaded with a straw filled with semen. The semen is kept in a tank cooled with liquid nitrogen. It is warmed to cattle body temperature right before it is to be used. An AI tech will use the pipet to deposit the semen just past the cervix giving it the opportunity to go into both horns of the uterus because cows only ovulate in one of their two uterine horns.
I know this was a quick overview, but I wanted to give you all an idea of the process before the time arrives. In a couple weeks I will hopefully have more pictures to share with you and maybe we can give you a little better understanding of it all.
I hope that you all enjoyed Mother's Day, talk to you next week.
by Brandon Greet