“A cow should have a calf every year.” For most cow-calf producer this is a true statement because the cow prices the exact same amount of money to store – even if it is or no it raises and weans a calf to sell.

You are watching: When is a bull too old to breed

Based top top the most recent Texas A&M AgriLife standardization Performance evaluation (SPA) database, it prices the typical Texas producer $796 to keep a mature cow about for a year. The course, not everyone is “average.” The lowest-cost-quartile producers just spent $618 every cow every year, while the highest-quartile producers invested $1,261 every cow every year.

If you break down where those expenses occur, most civilization would more than likely correctly guess feed and labor are among the best components. Yet it surprises many world depreciation is actually slightly larger. Collectively, depreciation, feed and also labor account because that 46 percent the the total annual cow expense for many producers.

The benefits

Controlled calving seasons have actually a variety of benefits that include improved herd fertility, more heavier weaning weights and much more uniform calf crops. Uniformity might offer an ext marketing choices and, when age variability is minimized, instead of heifers deserve to be much better managed to with a stylish puberty for that vital first breeding. Also, herd health and wellness programs are easier to implement and monitor in herds v a defined breeding season.

For example, program to regulate calf scours, pneumonia and other calfhood diseases are much easier to implement in similar age groups of cattle. Sexually sent diseases such together vibrio or trichomoniasis deserve to be recognized and also dealt with prior to they end up being chronic in the herd. Timely trial and error for reproductive illness such as BVD are less complicated to control in a herd through a controlled breeding season.

Most vaccines, and also especially those because that reproductive diseases, call for they it is in administered at certain ages or at a certain time in relationship to when reproduction is supposed to begin, and also a characterized calving season allows much more options such together strategic usage of modification live/killed vaccines. Managing herd nutrition is one more area that need to be considered: When livestock are supplemented, the whole herd gets fed. It is difficult to accurately supply supplement to dried cows and also lactating cows once they space together in the exact same pasture. Nutrient requirements are most influenced by lactation, and especially optimal lactation, which occurs about two months after calving.

The challenges

There are just 365 job in a year. Among the biggest difficulties to managers trying to keep cows on a 12-month calving expression is the reality a cow or heifer is pregnant for around 285 work of the year. That just leaves 80 days because that physiological processes such as calving, uterine fix (involution), resumption the the estrous cycle and also ultimately re-breeding to take place so the cow “has a calf every year.”

“Postpartum anestrus” is another challenge. Transferring a calf is stressful, both anatomically and also physiologically. Therefore cows and also heifers carry out not have estrous cycles because that a period of time post-calving. For most cows, this anestrous duration lasts a minimum the 45 days. It will certainly be much longer (often lot longer) if cows space in negative body condition at calving or if they have experienced calving difficulty. As Figure 1 depicts, cows that calve early will have much more time to recover from calving before breeding starts versus cows that calve late.

And, as Figure 1 also depicts, if supervisors want to save their cows calving on a true 12-month calving interval, the longest a calving/breeding season deserve to be is 3 months. Some supervisors use even shorter 60- or also 45-day seasons effectively.

Dealing with bulls

Removing bulls from the cow herd following the breeding season is the most common technique of regulating the reproduction season and thus regulating the calving season. However, part producers merely don’t have actually a ar to put herd bulls. This is particularly true for smaller sized herds with restricted land area or smaller herds wherein there might only be one or 2 herd bulls servicing a small variety of cows. Part bulls don’t remain where they space put, regularly tearing increase fencing and also other facilities in the process. This may again it is in true for smaller herds whereby a bull simply gets lonesome and also wants to it is in with other cattle.

The good news is: it is feasible to leave bulls v the cows year-round and also still maintain a calving season of three months or less. It just requires two main things: access to someone that is professional in one of two people palpation or ultrasound to recognize fetal age, or the use of calving records, and the “self-discipline” come cull pregnant females indigenous the reproduction herd.

To watch a small bit closer in ~ the process, an initial determine the moment of year you desire to calve and breed. For most producers, that reproduction season of three months or much less should probably enhance the time that year when pasture forage quality is the ideal – and most cows in herds the calve over prolonged periods will often tend to normally breed at the time that year anyway. It is most likely easiest to perform pregnancy diagnosis simply prior come those months you have actually targeted because that the calving season. An accurate strategy will count somewhat on the ratio of the herd calving exterior the wanted period.

But, for example, a rancher in main Texas desires to breed cows through the best-quality feather forage in the months of March, April and also May to develop December, January and also February calves. Pregnant diagnosis might be perform in November. Heavy-bred cows diagnosed in their third trimester would certainly be kept for the reproduction herd. Cows figured out as open or short-bred have the right to either be marketed as open up cows, or bred cows, or calved out and sold together pairs later – or even kept and bred and also managed in a separate herd i beg your pardon is then allowed attrition.

Another alternative is to usage calving documents from the vault year in location of pregnancy diagnosis, to similarly identify the females the either fit or don’t fit the desired calving period. This procedure is no doubt much easier to execute in smaller herds, or at the very least in smaller pastures, where cattle are easily and also frequently observed.

Remember, if bulls space with the cows year-round, over there is a chance heifer calves may get bred to bulls that might not it is in calving-ease sires. Therefore be certain to wean heifer calves prior to 8 month old or so. Also, when bulls space with the cows year-round, there is a greater chance of breeding daughters. This might not be the many ideal genetic situation. However for part producers, it might be other they simply decide they will certainly tolerate. Some managers who do keep bull daughters will adjust bulls every 3 years or so.

Others may decide to just sell every heifer calves. Instead of females room then purchased together either open up cows or bred cows that will calve during the preferred period. Establish there space inherent dangers to purchasing external cows if the health and also vaccination standing is no known. And also even then, conditions such as BVD, vibrio or trichomoniasis have the right to be lugged into the herd. The is probably a greater risk with the acquisition of open cows, however even bred cows deserve to be carriers, and diagnostic tests are problematic because that cows. The the safest strategy would be come buy instead of cows from well-managed herds and also monitor with suitable diagnostic testing.

Calving seasons need to be managed to make sure cows calve every year and are paying your way. Approaches to attain a 12-month calving interval may incorporate culling from pregnancy diagnosis, either through or there is no bull removal, or culling from calving records.

*

Thomas Hairgrove, DVM, is an associate professor and also extension specialist through Texas A&M AgriLife Extension.

PHOTO:For those that don’t have actually a ar to placed bulls, a calving season of 3 months or less have the right to still be kept – as long as the age of the fetus is determined and any cows space culled the didn’t do the breeding window.

See more: How Tall Is 63 Inches In Height Conversion Table, Convert 63 Inches To Feet

Photo by David Cooper.