We are reaching the end of calving season, with only about 20 more pregnant cows and heifers in the close up lot. We have already weaned two groups of calves off of their milk onto hay and sweet feed, with a third group on the way! It is hard to believe how quickly they have grown up…
However, at the dairy our work is never finished. Chores are always changing based on the time of year, and we have already started gearing up for our next breeding season. Right now, we are checking to make sure that all of our cows and heifers are cycling normally (i.e. coming into heat about once every 18-24 days) before we start breeding on January 1st. In our seasonally bred herd, it is very important to get the heifers bred on the first try if possible, so that they do not fall behind the rest!
Here is a short video showing what it means to “check heats.” In this video, the black heifer with brown ears is the one who is in heat. We call this a “standing heat” since she stands there receptively and lets the red jersey heifer mount her without running away. As you can see, they are very friendly–they always lick my jacket and boots and use me as a scratching post when I am standing out there checking heats 🙂
There are also two other methods used to check heats: tail chalk/paint and estrotect patches, both of which work on the same principle: the cow or heifer who is mounting will rub her sternum/brisket on the tail head of the one who is in heat. With tail chalk, this means that the color of the chalk is worn away by the friction. With estrotect patches, the patch changes color when it is rubbed or scratched (sort-of like a lottery ticket). Once we know that she is in heat, we record it in the computer so that we know when to expect her to come into heat again and we can be ready to breed her starting January 1. When a heifer or cow is determined to be in heat, we have t-minus 24 hours to breed her successfully, otherwise we will have to wait another 18-24 days for her to come into heat again. We will aim to have all of our cows and heifers bred by April 2013. Since their gestation lengths range from 9 to 9.5 months (or 270 – 285 days) in our herd, this puts next year’s calving season right on schedule to occur between September and December 2013.
Dr. Alley will be out on Thursday to perform post-partum (i.e. post-calving) checks on our cows to make sure that they are healthy and ready to be bred again. Time to study up on my reproductive anatomy and get some more palpation experience!