I hope you tuned into this Month’s newsletter. If you haven’t here is a quick preview of what was discussed:

Let’s talk about calving seasons for a minutes.  We like to have a tight group for our calving window.  Typically around 60 days.  When we turn bulls out the first of May, we leave them in with cows about 60 days.  This gives us a 60 day calving window.  WHY?  The closer in age your group of calves are, the more uniform your group is when it comes to weaning and selling them.  The more uniform a group just ensures their weights will be more tightly grouped together.  

The other theory behind 60 days, is it gives a cow up to 3 chances essentially to get bred during their heat cycle.  A cows cycles every 21 days.  Meaning she comes into heat every 21 days, and is in heat for roughly 12 hours.   Cows can only become pregnant when successfully bred during “heat”.  How do we know when she is in heat?  She will exhibit signs like restlessness, mounting other cows, allowing other cows to mount her, we call this “standing heat” meaning she is willing to stand still and be bred.  This gives the bull a 12 hour window to get her bred.  Having three chances to do his job, usually works out pretty well.  We also make sure our ratio of cows to bulls allows us enough BULL POWER!  HAHA a little cow humor there lol.  But in all actuality, depending on the country you run you may have a more or less cow ratio.  For us and the type pf ground we run, we tend to stick with the 25 cows to 1 bull ratio.  So much science in this cowology nonsense 🙂  The other thing to remember is a cow’s gestation is 285 days.  So, from time of conception calves will start hitting the ground in 285 days.  Give or take a few.  This begins our calving season.  And same goes for the last day the bulls are in with the cows, ending calving season, thus our 60 day calving season!  

The past few months we discussed EPD’s, genetics, crossbreeding, and animal health. It only seems fitting to now discuss the process that these decisions ultimately affect. In order for cow-calf producers, like ourselves, to raise healthy thriving calves for the consumer, we have to ensure reproductive success. Their are so many variables that goes into the reproductive management of a cow. In fact, some people specialize in college in just the this thing. But for the sake of keeping it reader friendly and simple, my plan is to break it down in bite size pieces!

First lets start with the cow! Before we can even be concerned with bull selection, breeding seasons, and calving windows, the COW, or in this case heifer needs to be the right age and body weight for the reproductive cycle to begin. Much of this is based on body fat. Once her body fat composition reaches the appropriate level and she is between 8-10 months of age, heat cycling can occur. Note, this may actually happen prior to or after the 8-10 months, all depending on biological, genetic, and feed factors. These are averages. Now this is all dependent on body condition scoring, BCS, as well. This BCS also affects the ability for her reproductive longevity and re-conceiving after her first calf. BCS is a measurement to use on cattle that visually accesses how much fat is on their body. See the chart below!

So once our heifer reaches the pubertal age and body fat composition is correct, it’s best to give her a few heat cycles before initial breeding. Waiting until 12-13 months as a minimum is best. Okay, so we have age and body weight covered. Now let’s talk about the entire Estrous cycle. The Estrous cycle is referred to the entire 4 stage cycle that a cow/heifer cycles through every 21 days. It is made up of proestrus, estrus, metestrus, and diestrus. In each of these 4 stages different hormones are present to aid and assist with follicle development. Follicle development is referring to the cow’s egg and possible embryo progression through the Estrous cycle. The stage in which a cow can conceive and be bred is the estrus cylce. It typically lasts 12-18 hours and this would be the only possible window of conception. Not to mention the rise and fall of hormones like estrogen and progesterone. Both of which are affected by which stage in the cycle the cow is in. But I promised to keep it simple. So sister! We have a lot going on during breeding season.

Now cattle are known as polyestrous. Meaning they cycle every 21 days 12 months of the year. So you can choose when it is best to calve for your feed and pasturing conditions, not to mention weather. You also want to make sure your cows are on the best feed possible when you have to re-breed. This is because this time period is the most taxing on them. Not only are they milking and feeding a calf, they have to increase their own BCS in order to reproduce and cycle. Cyclicity is the last thing to happen for a cow when it comes to feed requirements and nutritional needs.

So choosing when to turn the bulls out in order to to have calves born at the appropriate time can make or break your operation. Much more goes into it than just deciding when you want them babies to hit the ground. Not to mention we have to factor in our calving window length, as I touched on before, we like ours around 60 days, and that 285 day gestation. And who said it wouldn’t take a little Algebra in ranching 🙂

So there you have it. Years of college education wrapped up in a simple few minutes to understand the intricacies of a cow breeding season. Don’t forget, if you have any questions, PLEASE reach out! Thanks for reading and we will catch ya next time!