A Bull’s Ability to Breed Cows: Ratios, Strategy, and Timing

When it comes to successful cattle breeding programs, understanding a bull’s ability to breed multiple cows can be one of the first steps in deciding what strategies to employ for setting up your cow and bull breeding fields. Each bull is unique, and its specific strengths and weaknesses should always be taken into account before breeding.  

Bulls are highly adept at breeding with multiple cows throughout a single breeding season, which helps keep their genetics thriving. But not every farmer knows exactly where to start with cattle breeding projects, especially if it’s their first season. I live in farm-country, so many of my friends are cattle farmers. I wanted to understand the intricacies of cattle breeding so I sat down with a few of them to understand how they breed cattle. Here’s what I found out! 

Cattle Breeding Strategies for Success

Depending on the size of your farm and your long-term goals in breeding your bulls and cows, there are a variety of different breeding strategies that may work for you. Or perhaps you want to try something different this time around. Different breeding strategies can also depend on whether you plan to focus on beef cattle or dairy cattle or if you want to try to get a feel for both worlds with certain dual-purpose breeds. 

Regardless of your choice in cattle, these are a few things you need to consider before deciding on any one specific breeding strategy:

• Are you planning on having calves born in the winter or the spring? There are pros and cons to both, and neither one is the “best,” so be sure you know which one will work for you. Out of the 12 cattle farmers I interviewed, every single one of them breeds their cattle to birth in the winter months. Their reasons for this varied, but almost all of them came down to the ability to spread their business out all year. During the spring through the fall, they are planting, farming, and harvesting hay and other crops. By scheduling calving season in the winter months, my friends can take the busy season of calving and put it into a less hectic time of the year. 
• Are there personal things to consider which might affect your breeding plans, such as vacations or work obligations? There is nothing worse than having to take a business trip out of state right in the middle of calving season. Where I live, most cattle farmers are full-time farmers, but if you own a small herd, it will be critical to plan other obligations far enough ahead to really be available during calving time. 
• Is your bull healthy enough to breed, and are your cows experienced broodstock or fresh heifers? On the outside, the breeding “tasks” seem easier for the bulls – but both the bull and your cows will have certain needs that must be met for successful breeding. I’ll cover this later in the article- and how the answer to this question brings up the topic of artificial insemination. 
• Are you aware of any differences in breeding beef cattle instead of dairy cattle that may apply to your farm? Generally, the differences are small, but small differences can become big issues if you are unprepared.
• Have you made sure that your chosen bull is receiving proper nutrition outside of the breeding season? You wouldn’t run a marathon without training yourself, and your bull is no different! Be sure he is prepared for the upcoming breeding season.

Since no single strategy will work for every bull, or even for the same bull every year, you need to know your animals well and make the right choices on this behalf to give them the best opportunity to produce healthy offspring for you. This includes taking into account bulls’ genetics, overall health and body condition, your farm or rented pastureland, and more.

Factors that Affect Successful Cattle Breeding

Successful breeding is not always just putting a bull with a cow and hoping for the best. If you want the highest quality progeny from your bull, you will need to put in a bit of work yourself. A range of factors can affect breeding success; we will cover just a few of them below.

• Bull Genetics:
  Obviously, the first and possibly the most important factor to consider is the bull’s genetics. There is no universal law that says you cannot take a genetic mess of a bull and let him breed with your cows – but if you want the best possible return on the time and money it takes to prepare your cattle for breeding, you should always go with the best genetics you can find. Whether this means buying a new bull, renting a bull from a neighboring farm, hiring a bull for stud services, or purchasing frozen semen for artificial insemination, genetics is the foundation that everything else will be built upon.
• Cattle Breed:
  Some breeds are just less talented when it comes to reproducing than others. Some are also much more prone to have temperament issues or difficulties calving. For example, some large-boned beef breeds such as Hereford can be prone to calving issues, resulting in a higher calf or cow mortality. A variety of dairy bulls have been known to show temperament issues, making handling them more difficult or dangerous for the average small farm. Holstein can also suffer from lower fertility compared to other breeds, as selective breeding focuses more on the Holstein cow’s milk production over anything else.
• Climate Affects Libido:
  Most of us probably wish we lived in a perfect climate, where summers were warm but not overly hot, and winter brought snow but not 12 inches of ice covering everything. Unfortunately, you are probably in one of the areas where the summer gets hot and humid, or the winters are cold and miserable. While cold temperatures can cause some problems, heat stress is one of the biggest causes of poor breeding outcomes. Extremely high temperatures can noticeably affect bull fertility and sex drive, which leaves some farmers searching for ways to keep their cattle cool during the summer or leaving them forced to breed in less optimal months simply due to the weather.
• Bull Age:
  While a beloved bull can successfully breed well into the 10 or 12-year-old range, most herd bulls are retired from breeding at the age of 4 or 5. This ensures they are breeding only during their prime, when their libido and fertility are highest, and are then either sold or sent to the freezer. If you are attached to your herd bull and want to keep an aged bull longer (how to know when to cull your cattle), you may start to notice a reduction in fertility and sex drive as he ages. However, if he is kept in excellent health and body condition, this may not be an issue until he is 10 or 12 years old, sometimes even older. For smaller farms where cattle are more of a hobby than a business, a slight reduction in fertility may not even be anything to worry about. If that applies to you, don’t be afraid to keep your favorite bull around for many breeding years.

Before breeding your bull, it’s a good idea to make sure he’s able to breed well. A bull physical averages around $40-60 dollars, but the cost of a bull underperforming can be as much as $20,000! That’s because a bull can breed 20-30 cows and if he fails to impregnate them, the farmer loses that many calves. If each calf grows to 650 lbs before being sold and the farmer can sell the cattle for $1 a pound, he loses $20,000 on an infertile bull.

A bull breeding exam will examine not only the health of the bull, but the vitality of his sperm and the likelihood he will reproduce. If sperm is lively and has at least a 70% healthy rate, the bull is considered fit for breeding. A vet can perform the exam, usually in about an hour.

Cow to Bull Ratio in Breeding

When planning for cattle breeding, you should think about how many bulls you wish to keep with your cows. Keeping too many bulls on your property may end up causing more problems, so some farmers opt to start with just one. But how many cows can one bull breed? 

When breeding cows, many farmers choose to keep a bull on the property full time.  If you choose to do this, select one exceptionally healthy and genetically sound bull, known as the herd bull, and keep him with around 10-20 cows throughout the breeding season. Breeding seasons may be as short as 45 days or as long as 90 days. It will depend on the bull’s health, as well as the farmer’s intentions and plans.

Other farms may choose to stagger their breeding groups. By keeping a small number of cows with one bull, then switching him with another bull of similar genetics. This can be his son or sire. This not only ensures that each bull gets plenty of time to rest in between breeding. It also ensures that every cow gets bred even if the first bull may not have been introduced at the most optimal time during a cow’s estrus.

The number of cows kept with a single bull can vary depending on the bull’s physical health, overall experience with breeding, and the willingness of the cows. A healthy, experienced bull can easily cover up to 30 cows in a single breeding season of roughly 60 days. But, most small farms keep the number of cows to around 10 for each bull. This gives the bulls plenty of time to breed with each of the cows successfully and gives them ample time to eat, drink, and rest as needed.

Best Time of Year to Breed Cattle

The normal gestation period for most cattle is around 285 days or about 9 and a half months. This estimate can vary by a few days, depending on the specific breed. However, smaller breeds, such as Dexter and Zebu, maybe closer to 280 days. Larger breeds, such as Simmental and Watusi, have a gestation that’s closer to 290 days. This means you have to plan well in advance to be sure your bull is breeding the cows at the right time of year. 

Estrus is the time of year when a cow can be impregnated. One of the biggest benefits of breeding cattle is they can be bred at any time of the year. That’s because cows do not have seasonal estrus. Most cows will have their first estrus between the ages of 9 and 15 months. It will last for 3-5 days, then repeat in around 24 days until the cow is impregnated. 

While there is no “ideal” time of year to breed your bull to your cows, the best time can depend on the area you live in and on your feeding plans.  Decide whether or not you plan on letting the cattle graze on pasture or if you will be supplementing their intake with hay or grains. If the weather is nice, the fields are lush, and you are confident that your pasture can support your cattle’s nutritional needs, there is no reason why you can’t just let nature take its course and allow the bull to breed naturally with your cows throughout the year.

But some farmers prefer to breed their cows all around the same time so that they can calf the herd during a single season. Often, this involves winter calving season.

Cold weather calving comes with both benefits and problems for the cows, calves, and farmers. Arguably the biggest benefit to winter calving is the reduction of external parasites such as ticks and fleas. A calf can easily become covered in ticks during the summer, leading to anemia and possible death if not noticed early on. 

Winter calving is also very convenient for farmers who may need summer months to plant and harvest hay. However, the cold can lead to higher cow and calf mortality, especially if they cannot get out of the weather and onto dry ground. It’s important to provide your pregnant cows with a barn or lean-to help with those critical first few hours. This will help and ensure your calves make it through their first winter.

Calves born in the warmer months can be more prone to hoof infections, internal and external parasites, and diseases. Spring and summer bring rain and humidity, which can cause your cattle pasture to become muddy and waterlogged, directly leading to hoof issues in the growing calf. In addition, insects may use water sources as their own breeding grounds, leading to waterborne illnesses in your herd.

Another thing to consider is how the bull might handle breeding in certain seasons. One bull servicing multiple females can be exhausting for the bull. This will quickly use up his energy reserves if he is not given time to rest. Add the stress of breeding into an extremely hot or cold environment, and you may end up having to deal with poor fertility, heat stress in your bulls, or even hypothermia in some extreme cases. 

Using Yearling Bulls on Multiple Cows

You have a healthy young bull; he has been raised well, fed well, and is showing signs of being ready to breed. The cows are receptive and ready, and you, as a new farmer, are excited about the thought of venturing into the world of breeding cattle. But, your bull is just a yearling. Should you wait until next season to breed him, or is he ok to breed as a yearling? 

There seem to be two very distinct schools of thought on breeding yearling bulls. Some people have had great success breeding yearling bulls, while others prefer to wait until the bull is two or even three years of age and has finished growing. 

A bull’s sex drive, or libido, is defined more by his body weight and overall health than his age. Yearling bulls are perfectly able to successfully and safely breed with multiple cows. However, it is recommended that farmers limit a young bull’s first breeding season to around 45 days. This helps to ensure he stays in good body condition, remains at a proper weight, and as a result, his libido stays high through the current and future breeding seasons. Ultimately, you will have to use your best judgment on the number of cows your yearling bull can cover since it will depend on his own unique abilities.

Differences in Beef and Dairy Cattle Breeding

Overall, there are no drastic differences in breeding beef cattle or dairy cattle. Dietary needs will be the biggest difference between bulls, as beef cattle will require more overall weight gain to remain in the best body condition. They have stocky legs and stout bodies. You will probably find your beef bulls eating more hay per day than dairy bulls do, which means you need to ensure you have plenty of hay on hand with a source for more as needed.

On the other hand, dairy cattle are much leaner with less muscle growth compared to beef cattle. They have leaner bones and more angular bodies than beef cattle. They also usually have a higher amount of grain in their diet but will benefit just as much from good quality hay as their beef counterparts do. 

All bulls, regardless of their breed or purpose, will need a proper diet to help them gain or maintain a healthy weight, so be sure you know what weight gain is best for your individual bull well before the breeding season starts. You don’t want to send your best athlete into the Olympics without the proper conditioning!

Bull Nutrition is Highly Important

Much of the focus of proper feeding is placed on the cows since they will be the ones carrying the calves to term and being expected to produce enough milk to raise that calf. However, many people overlook the importance of proper nutrition for the bull as well. This is not something you want to ignore, especially when preparing for an upcoming breeding season. Bull nutrition can affect the bull’s health in general and the viability of his sperm.

What is the best feed for a breeding bull? It is common practice to keep the protein levels of any grain-based diet to around 10% and ensure your bull is gaining around 2 pounds of healthy weight per day, not just fat but also muscle. This applies to both dairy and beef cattle, but beef cattle will gain more muscle. Switching your bull to a proper diet should be done at least 4 months in advance of the breeding season to give him plenty of time to put on the right amount of weight and to ensure he can stock up some energy reserves for the upcoming task. 

Some farmers choose to keep their bulls on pasture before and during the breeding season to save on feed costs, and this works as long as pasture is suitable for grazing. But, more and more farms are choosing to selectively condition their bulls on a grain and hay ration in preparation for the next breeding season. 

Grains are commonly a mix of cracked corn, soybean meal, wheat middlings, and rolled oats with the addition of trace minerals such as zinc, selenium, and manganese. Hay is often a mix of alfalfa hay or orchard grass hay but can be adjusted depending on what is available to you throughout the year. Always look for the freshest hay you can find or at least hay that has been properly stored, and try to get both mid-season and end-of-season cuttings for the best nutrition factor. Never feed your cattle any moldy hay or hay that looks like it may be infested with insects or rodents, as this can lead to poor nutrition intake, respiratory distress, and diseases.

Vitamins for Healthy Bulls

You’ve ensured your bull is eating enough grain and hay, but are his vitamins and minerals balanced? Often overlooked or ignored, vitamins and minerals are an essential part of maintaining a healthy breeding bull. Zinc is vital as it has been directly linked to bull fertility. A zinc deficiency can reduce testosterone production and directly impact the development of young bulls’ primary sex organs. 

Some lucky farmers can leave their bulls on pasture and know they will get all of the vitamins and trace minerals they need from the earth to be healthy and happy. Still, many others must rely on supplemental vitamin and mineral blocks or loose trace minerals mixed with grain rations to provide those missing nutrients. Most vitamin blocks you can purchase for your cattle to lick as they please already include zinc, but some do not. So if you have been noticing fertility issues in your bull, be sure to consider his zinc intake.

Vitamin A can also play a role in bull fertility and overall calving results. Deficiencies in Vitamin A may first be exhibited by stiffness in the bull’s leg joints, making it harder for him to mount a cow during breeding properly. It may also lead to poor calving outcomes, early calf abortions, and a calf’s failure to stand.

Selenium is arguably one of the biggest culprits in poor fertility and overall failure to thrive in cattle. Many areas of the world face selenium deficiencies and will be forced to supplement this vitamin by free choice blocks. Selenium deficiency has been directly linked to poor fertility, poor milk production, and muscular dystrophy in newborn calves.

Key Vitamin that Affect Fertility:

• Zinc
• Vitamin A
• Selenium

Pros and Cons of Artificial Insemination

Maintaining a full-time bull on the property may result in more work than some farmers care to do. This is especially true with the feeding, conditioning, and safe handling requirements.  If you choose not to keep a bull on the property at all but still want to venture into the world of cattle breeding, you can have your cows impregnated through the use of artificial insemination. 

Artificial Insemination involves obtaining preserved bull semen from another farm and implanting it into a cow’s uterus in estrus. This method will remove all of the added hassles and upkeep costs of keeping a bull on the farm long-term. But, it can also end up being more costly because you are paying for the cost of the semen itself, for its overnight shipping costs, and for it to be safely introduced into the cow by a veterinarian. 

There are also added risks involved. These risks include the risk of the semen not implanting properly the first time or the timing of estrus being off. This can lead you to purchase additional semen for more attempts or to scratch that cow off the list for the current breeding season. This can end up being a very costly option for some farmers to consider, but at times it may be the only option for you to get the right bull bloodlines into your stock.

However, the benefits can also outweigh the risks. For example, you may not be able to purchase that Grand Champion bull at this year’s dairy expo, but you might very well be able to purchase his genetics. Being able to purchase and receive bull semen worldwide can open hundreds of doors in advancing your own breeding program. You’re also able to “shop around” for the best genetics that compliments your cows’ lineage, leading to even better calves than you’ve had before. 

Artificial insemination allows farmers to diversify and improve their cattle herds much faster than through traditional breeding. Professionals are able to narrow down very specific traits of bulls. For example, a heifer will often be artificially inseminated with sperm from a bull that provides smaller calves that will still grow into a large adult. This helps to reduce birthing problems with new mothers.

Additionally, if the bull’s semen is collected and stored properly, it can remain viable for 20 years or longer from the time of collection. This means you may be able to obtain the genetics from bulls that have long since died or from your past bulls, which hold a special place in your heart. 

Pros of Artificial Insemination

Cons of Artificial Insemination

Eliminates the need to keep a bull on the property or rent one Saves the hassle of caring for and handling a live bull Saves transportation costs and hassles for transporting rented bulls Allows you to choose the lineage for your stock from anywhere Allows for a faster improvement of a cattle herd  Gives farmers the opportunity to breed-specific traits into their herd and to keep the herd genetically diverse.

More costly than renting a live bull Costs to ship and have it implemented by a vet Can be tricky to learn Doesn’t always cause pregnancy  Risks of bad timing or failed implementation Each dose will need to be purchased, as opposed to renting a bull to breed with multiple cows

There are several costs to artificial insemination. Often farmers use medicines to cause all the cows in a herd to go into heat at the same time. That costs an average of $30 per cow. Bull semen can run from $10 to $1,000 per sample, depending on the qualities of the bull and the demand for those genetics. The cost to artificially inseminate a cow averages around $10 a cow, especially if an entire herd is being inseminated at the same time. Even with the additional costs, AI can be cheaper than using a bull, especially if it helps to eliminate other medical issues.

I spoke with Dr. Chase Staker, DVM, at Mountain River Veterinary Hospital about Artificial Insemination. He has seen emergency cesareans of cows decrease by 200% with the increase of AI. That’s because smaller cows can be inseminated with semen from a bull that’s matched to her unique needs, allowing her to birth a calf that doesn’t require medical intervention.

Closing Thoughts

When planning cattle breeding, arming yourself with plenty of knowledge beforehand is vital. 

There are many factors to consider, and unfortunately, you may run into conflicting opinions. But, once you understand the needs of your bull or options for breeding, the confusion will clear, and the road ahead will be much easier to follow.

Before long, you will be watching many months of hard work fully pay off when your bulls’ first offspring take their first wobbly steps on your very own farm.