How Many Cows Can A Bull Breed?

How Many Cows Can A Bull Breed

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How many cows can a bully breed? Most farmers are interested to know about the mating capacity of a bull. To put frankly, all too often, bulls are not a priority up until the breeding season.

Most farmers buy bulls prior to the breeding period to save resources and cut down feed expenses. However, bulls suddenly come into the limelight when it is time to breed cows.

The reproductive performance of a bull is affected by many factors like physical ability, sperm production, and quality.

Farmers should practice good bull management to reduce stress and minimize the risk of injury to fellow animals or people.

It should be decided how many bulls will stay with the herd. Having sufficient bull power when cows are likely to be on heat ensures good reproductive performance.

How Many Cows Can A Bull Breed?

Bulls are considered nothing more than necessary overhead like feed. Bull is an indispensable part of the herd, especially during the breeding season.

Most farmers are unaware of how many bulls should stay with the herd, often, they run too many bulls in fear that not all cows would get covered.

Therefore, it is better to understand the bull-to-cow ratio to run the required number of bulls with the herd. So, how many cows can a bull service in a breeding period?

Though the number varies depending on the age and ability of the bull, therefore, it is impossible to give an exact answer.

However, the typical bull: cow ratio is 1:20-30. Mature bulls have a ratio closer to 1:30 whereas a yearling bull can service approximately 20 cows.

The number of cows a bull can service in a normal breeding season is different for experienced and inexperienced bulls.

Experienced Bull

Many experts believe that an experienced bull over 2 years of age that passes the breeding soundness exam can service up to 30 cows in a 60 to 70 days breeding period.

Some data even suggest that an experienced bull has the ability to mate as many as 60 cows in a 70 days breeding period without compromising the pregnancy rates.
Inexperienced Bull –

Inexperienced bulls below the age of 2 years cannot service many cows and should only be exposed to 15 to 20 cows in a breeding season.

As per one rule of thumb, a bull can mate as many cows as his age. For instance, a 15-month-old bull should only service 15 females in the typical 60 to 70 days breeding season.

The ability of a bull to mate the number of cows is not predictable. Therefore, many farmers rely on breeding soundness exams to get accurate results about non-fertile bulls but it can not help in determining or pinpointing bulls with low fertility.

Factors Affecting the Mating Capacity of a Bull

There is no fool-proof way to know how the bull is going to perform in the natural breeding system. Some factors that affect the fertility rate or mating capacity are

Seminal Quality

It is the quality and quantity of the semen produced by the bull. In other words, it is the quality achieved as a result of genetic composition minus the detrimental effects of the environment in which the bull was raised. Seminal quality is affected by both genetic and environmental factors.

Semen quantity equates to the number of sperm cells produced whereas the semen quantity is the number of abnormal sperm cells and the motility of sperm cells. The cost of bull semen also depends on genetics.

Conduct a Breeding Soundness Exam (BSE) to evaluate these factors. Generally, Semen quality is affected by health, nutrition, disorders, etc.

Scrotal Circumference

Testicular size and scrotal circumference is determined by the genetics of the animal and have an important influence on the reproductive competence and mating capacity of the sire.

Bulls with smaller testes have likely decreased sperm output and increased numbers of morphologically abnormal spermatozoa.

Research conducted on 2000 bulls of varying ages showed that 23% of bulls with 32cm of scrotal circumference had better seminal quality.

Whereas, bulls with 38cm scrotal circumference have increased seminal quality, however, no further improvements were recorded in bulls with even larger testicles.

So, the scrotal circumference can have an impact on the number of cows a bull can breed.

Genetic Factors

Other factors that influence the mating capacity of an individual are seminal quality, testicular consistency, some recessive trait, and scrotal shape.


Age affects the seminal quality and therefore alters the bull to cow ratio. The seminal quality is increased for about 4 months after the attainment of puberty.


Nutrition alters the seminal quality of an individual sire. Many studies and research have emphasized the importance of nutrition on seminal quality.

Feeding high-energy diets to bulls have the most detrimental effects resulting in sperm production, storage, and motility and an increase in abnormalities.

Only feed a medium-energy and nutrient-rich diet for improving overall health and seminal quality.


Seminal quality and the breeding capacity are dependent on the libido and the mating capability.

In simple words, it is the willingness and eagerness of the bull to service a cow.

Libido or serving capacity can be defined as sex drive and competence to mate which affects the bull: cow ratio greatly.

Related Do We Eat Bulls Just Like Cows?

Importance of Mating Capacity

The reproductive efficiency of a bull is often overlooked, resulting in a loss in the cow-calf business.

Therefore, invest in a sire that can effectively impregnate more females in the given period. If one pushes the bull: cow ratio up, the mating capacity will increase whereas the fertility will reduce.

Use the new tools and tests as well as observe the bull’s breeding competence to reduce the risk of reproductive failure.


Hopefully, you got the answer to how many cows can 1 bull breed? Well, the answer may vary depending on different factors but it is close to 20 to 30 females in a breeding season.


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