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‘Crazy’ cows can affect reproductive performance

Emily Smith and Jordan Thomas for Progressive Cattle Published on 10 September 2020

Many of us have had those “crazy” animals that don’t quite seem worth the hassle. But, have you ever considered that crazy cows might actually be hurting your bottom line?

Excitable temperaments are associated with poor production due to factors like reduced dry matter intake (DMI), lower average daily gains (ADG), and lower-quality carcasses. While we can improve temperament through selection decisions, making genetic progress toward a more docile cow herd takes time. Plus, even docile cattle can become stressed in response to management. It is especially important to be mindful of animal stress around the time of breeding, as stress at this time can result in decreased reproductive performance. In all kinds of management systems and in all types of cattle, cows with excitable temperaments can have reduced pregnancy rates or increased rates of pregnancy loss. Fortunately, several strategies are available to mitigate stress associated with temperament. Producers should evaluate their herd, facilities and overall management to determine how implementation of the following practices might improve reproductive outcomes.


Negative outbursts of temperament are typically only observed when cattle experience abnormal scenarios or have stressful interactions with humans or other animals. This can occur during the breeding season through interactions with new bulls, handling during synchronization protocols, or introduction to new locations or management groups. Several mechanisms have been suggested for the way these stressors exert systemic effects on reproductive processes. Research trials have demonstrated that cows with excitable temperaments consistently produce increased levels of the stress hormone cortisol, which can inhibit ovulation, slow follicular development, reduce oocyte quality and delay the onset of puberty. Indirect impacts are also observed in excitable animals as altered behavior may reduce feed intake and increase activity. This can result in energy deficits that reduce body condition, which is known to be a significant detriment to reproductive success.


Although all herds stand to benefit from management practices that reduce stress, significant progress can be made to reduce the degree to which the herd is prone to stress during handling. Investigations into the heritability of temperament suggest that progress can be made by selecting against excitable temperament on both the sire and dam side. Many breed associations publish an expected progeny difference (EPD) value for docility that can be used as an effective tool for making genetic progress in temperament.

In addition, temperament should be considered when making selection or culling decisions, especially when evaluating heifers for replacement. It just isn’t worth it to develop temperamental females as replacements when better investments can be made. On more than one occasion, we have observed that sorting out heifers with particularly excitable temperaments improved the behavior of the entire group of heifers being developed. One bad apple can truly spoil the whole bunch.

Should cows be culled simply because of poor temperament? Most of us only consider culling the crazy cow after she has injured us or come close, but that may not be the best business decision. Though injuries are expensive enough in their own right, temperamental cows can also drag down the quality of the calf crop. Excitable temperament of a dam is correlated to excitable temperament of her calf, not only through genetics but through learned behavior.

We usually don’t struggle to identify the most excitable animals in our herds. Nevertheless, scoring systems have been developed as tools we can use to more objectively assess temperament. These systems consider factors such as the animal’s reaction to human interaction in a pen (pen score), the animal’s behavior when restrained in a chute (chute score) or the speed at which the animal leaves the chute following handling (exit velocity). Using one of these scoring systems to evaluate your herd allows you to make initial culling decisions and establish long-term guidelines for managing temperament.

Facilities and handling

Ensuring low-stress human-animal interaction by improving the design of animal handling facilities has huge benefits for both you and your cattle. Facilities designed with the natural predator-avoidance behavior of cattle in mind are less likely to cause outbursts of aggressive or excessively flighty temperaments.

Ultimately, the stockmanship of the personnel handling cattle is equally, if not more, important than the design of the handling facility. When direct animal interaction is necessary, such as when loading cattle into a squeeze chute or alley, handling practices can significantly increase or decrease stress associated with excitable temperaments. We can avoid excessively exciting cattle by using the concept of pressure and release, moving them by point of balance, limiting use of prods and minimizing unnecessary noise or distracting stimuli. Inexperienced personnel should never handle excitable cattle without instructional supervision by an experienced stockman.

Consider enrolling in stockmanship training courses, establishing training requirements for all personnel and conducting periodic evaluations to ensure that low-stress handling practices are being used across the farm or ranch.


While negative human-animal interactions during the breeding season may have direct impacts on reproductive success, management can also impact whether or not cattle have negative temperaments to begin with. Patterns of handling early in life shape the development of an animal’s temperament. Evidence suggests that improving temperament is most effective when attempted before the first breeding season and that acclimation of cattle to human contact both before and after weaning can greatly improve temperament.

Calves exposed to frequent human interaction in a low-stress manner are less likely to express excitable temperaments in maturity. While repeatedly exposing calves to handling may be impractical to implement in some systems, we can take advantage of handling events like vaccination to implement low-stress techniques and avoid negative human-animal interactions.

These concepts should be applied all the way through heifer development, as acclimating heifers to facilities and handling has been shown to reduce cortisol levels, drop temperament scores and allow heifers to reach puberty faster. Effective acclimation can be achieved through repeated human interaction during the one to two months before the first breeding season. Handling events that occur normally in a heifer development program provide the perfect opportunity to acclimate heifers to the facilities, equipment and handling they will encounter during the breeding season and throughout their productive life. Whether implementing vaccination programs, conducting pre-breeding evaluations or carrying out estrus synchronization protocols, prioritize low-stress animal handling. You can shift the future temperament of your herd.


Reproductive performance is critical to the profitability of any cow-calf or replacement heifer development enterprise. Minimizing stress prior to and during the breeding season is essential. Screening and selecting cattle for acceptable temperament can ultimately result in improved reproductive performance. Just as importantly, management practices that promote acceptable temperament, like low-stress stockmanship and acclimation of animals to handling, are low-cost ways to significantly impact reproduction. Finally, getting rid of the crazy ones won’t just reduce your stress, it will reduce your herd’s stress too.  end mark

PHOTO: Most of us only consider culling the “crazy” cow after she has injured us or come close, but that may not be the best business decision. Photo by Carrie Veselka.

Emily Smith is a graduate research assistant at the University of Missouri. Email Emily Smith.

Jordan Thomas is an assistant professor and state cow-calf extension specialist at the University of Missouri.