Stress is a major factor that influences the susceptibility of cattle to disease. As a consequence of this, how and when certain management practices are conducted can have a substantial impact on cattle health. Heat and cold stress are also capable of impacting immune function and therefore can result in adverse health outcomes. Care should be taken to avoid, minimize, or alleviate stressors whenever possible.
Aside from birth, weaning is one of the most stressful events that a calf will experience. Weaning is stressful because the calf is removed from its dam and has to adjust to a different diet and environment, along with potentially unfamiliar animals, which increases the potential for pathogen exposure and disease transmission. Management procedures should aim to minimize stress to calves throughout the weaning process.
Castration and dehorning should be performed before weaning, and preferably before cattle reach ~136 kg (300 lb) of body weight. In addition, calves should be vaccinated with at least one round of clostridial and viral bovine respiratory disease (BRD) vaccines before weaning. Completion of vaccination, deworming, implant placement, and any other necessary management procedures before weaning allows calves to be weaned without handling and decreases the amount of stress they will be subjected to throughout the process.
Preconditioning is a process that prepares feeder calves for marketing, transportation, and the feedlot environment. This process typically includes weaning, administration of certain vaccines, deworming, castration, and training calves to eat from a feed bunk and drink from a water trough in a pen. The concept of preconditioning is based in part on immunologic and nutritional principles.
Preimmunization, or vaccination of calves before shipment from the ranch to the feedlot, and its positive effect on health and performance throughout the feedlot finishing phase established the basis for developing formal preconditioning programs. In addition to vaccination, more recent efforts have been directed toward increasing the number of days calves are weaned before marketing, as well as improved cow-calf management procedures on the ranch, such as genetic selection and nutrition, that assist calves in making an easier transition to the feedlot environment.
Preconditioned calves typically withstand the stress associated with marketing, commingling, and transportation much better than calves that have not been weaned and preconditioned. Preconditioned calves typically begin to eat and drink much more quickly and experience less morbidity and mortality.
Premiums associated with preconditioning are typically $5 to $10 per 45 kg (100 lb) if calves are marketed appropriately. In addition, preconditioning periods provide further opportunity to add value to calves through added weight if calves are managed appropriately and the cost required is less than the market value of the gain.
Backgrounding and stockering serve as intermediate production phases between weaning and finishing where calves are grown over an extended period of time on pasture (stockering) or in a dry lot (backgrounding).
Backgrounding or stockering is another strategy often used to achieve objectives similar to preconditioning; however, it generally occurs over a longer period of time (> 63 days). Nonetheless, not all calves will be weaned and preconditioned before sale, which increases the risk of morbidity and mortality. As such, these calves typically require different, more intensive management than lower-risk calves require throughout the first few weeks after arrival.
An understanding of the principles underlying the nutrient requirements and nutritional management of cattle is critical to ensuring that nutrition does not limit immune function. Gestational nutrition of the dam has lasting implications for calf health through its impact on both the quantity and quality of colostrum available to the newborn calf. Nutrient-restricted cows are expected to provide less and lower-quality colostrum to their calves. Because colostrum is the means through which the newborn calf's immune system is populated with antibodies, gestational nutrition of the dam can have a major impact on calf health.
Undernutrition of gestating females can lead to the following:
an increased incidence of dystocia because of lack of weight and size
weakness at the time of parturition
weak calves at birth
high incidence of prolonged postpartum anestrus, which leads to a high percentage of nonpregnant animals that will need to be culled
For growing cattle, nutritional deficiencies or disorders are more common on stocker and backgrounding operations than on feedlots; however, they can occur anywhere. For more information on the interaction between nutrition and health, see the topic Nutritional Requirements of Beef Cattle Nutrition: Beef Cattle .
Stress associated with cattle handling and human-cattle interactions can impact cattle health. Operations that effectively implement low-stress handling practices typically observe decreases in cattle morbidity and mortality. This is particularly true for operations that experience relatively high rates of morbidity and mortality.
Low-stress handling requires more than merely an understanding of an animal's flight zone and point of balance. Because attitude greatly influences handling success, implementation of low-stress handling practices often requires an active commitment to changing any negative handling behaviors and embracing alternative strategies.
Effective low-stress handlers typically understand and embrace principles of cattle behavior, such as:
Cattle want to see a handler and therefore do not work well when directed from behind.
They typically want to move away from and go around you.
They respond to pressure, both applied and released.
They want to be with and therefore move toward other cattle.
They will typically focus on only one thing at a time.
In addition, to ensure adequate space and air flow, similar low-stress concepts should be applied to transportation of cattle.
Facilities are also capable of impacting health by decreasing stress associated with working events. It is important to recognize that facilities themselves are tools, and should make the job easier. To that end, facilities should be designed to minimize stress to both cattle and personnel.
Size, spacing, orientation, layout, and ability to be modified as needed are important considerations when designing or modifying facilities. Mistakes in any of these areas can substantially impede the effectiveness of a working facility.
Emphasis should be placed on facilitating the seamless flow of cattle through the system. The negative impact of poor handling techniques cannot be not overcome by optimal facility design, but the limitations of a facility can often be overcome by good handling techniques.
Once designed, facilities should be modified as necessary to adapt to experience and be as effective as possible. All areas should be regularly inspected to identify problem areas and avoid injuries to both cattle and personnel. Facilities should also be designed and maintained to promote cleanliness, rapid drying, adequate ventilation, safe footing, and to prevent the accumulation of mud and manure.