Bovine Health Briefs


Vaccination: A Herd Health Basic for Fall

Managing disease risk is an important aspect of a good herd health program, and vaccinations help reduce the probability of disease. Choice of vaccine depends on herd disease history, management factors, and your veterinarian's knowledge of a vaccine's success rates in your area.

Replacement heifer vaccinations may be the herd's most important injections. Introducing immune animals into the herd lessens the risk of disease spread. Replacement heifers should receive vaccinations as young calves and also near weaning time, similar to other calves in the herd. The most common vaccines given at weaning time are for brucellosis, bovine viral diarrhea (BVD), red nose (IBR), leptospirosis, trichomoniasis and vibriosis.

Benefits for All by Preconditioning Calves

Preconditioning calves between weaning and marketing makes good sense for all involved – the producer, the buyer, and the calves. The producer is able to attract a higher price, the buyer sees welcome reductions in labor and medical costs, and the calves experience fewer health problems. Healthy sale barn calves can fall apart the first few days they're started out on a new place, but preconditioned calves typically do well from the beginning. Preconditioning can be worth a premium of several dollars per hundredweight.

In preconditioning, calves generally are weaned at least 21 days before selling, receive a standard vaccination and deworming program, are eating a preconditioning ration, and previously have been dehorned and (for bull calves) castrated.


Keep Herd Health Simple

To be able to use herd health programs effectively, you need to know what a healthy herd is.

If animals' disease resistance level drops below the disease challenge level, sickness occurs. If the disease challenge level rises above the resistance level, sickness occurs. The worst scenario occurs when the resistance level is dropping at the same time as the disease challenge is rising.

The resistance level of an animal or herd can be lowered by stresses such as poor nutrition, transportation, winter storms, heat stress, fluctuating daytime/nighttime temperature, and processing. The disease challenge level can be increased when cattle from different sources are mixed together, when a sick animal is added to a herd of susceptible ones, and when susceptible cattle are added to a herd of sick ones.

To keep herd health simple, (1) recognize disease challenges; (2) know when they occur; (3) raise resistance levels before the challenge occurs; and (4) reduce the challenge. We can help.

Quick Tips for Identifying Sick Cattle

The experienced feeder can usually identify sick animals by visual inspection. The following technique, however, is offered to the inexperienced handler or anyone who doesn't have the "knack" for identifying sick cattle.

Process cattle before noon on the day after arrival. (Rising temperatures in the afternoon can affect the animals' body temperature and appearance.) As soon as an animal is restrained in the chute, take its temperature with a rectal thermometer. Designate as sick all cattle with a rectal temperature of 104°F or greater. Designate as sick all visibly ill cattle regardless of body temperature. Visible signs of illness include excessive nasal discharge, labored breathing, harsh coughing, moderate to severe depression, or bloody diarrhea. Animals exhibiting only loose stools or non-bloody diarrhea are not considered sick. Mark or tag the sick ones, treat them according to a predetermined program, and record the treatment.


For Best Results, Start Healthy

A good health program begins by avoiding purchase of sick animals or those exposed to sick animals. Preconditioned calves should have less sickness.

Upon arrival, calves should be inspected as they are unloaded. If they are unacceptable, they should be reloaded or the seller should be notified immediately for a price renegotiation. Calves should be batch weighed on arrival to determine shrinkage. Shrinkage of 7 to 8 percent or more is generally indicative of problem cattle. They probably will require more intensive management during the observation period. Once accepted, calves should be placed in small dry lots with free access to good quality grass hay and fresh water and be allowed to rest overnight. Processing can begin at daylight the next day.

Help Calves Resist Disease by Vaccinating

All newly arrived stocker calves need to be vaccinated for diseases to which they will be exposed. If the cattle are from unknown origins (commingled marketing), chances are that you may be starting the vaccination program for many of the calves. If the calves originated from a direct sale, they may just need booster vaccinations. In either case, the objective is to raise the calves' resistance level to certain diseases as rapidly as possible.

The majority of backgrounding calves need to be vaccinated against IBR, PI3, BVD, BRSV, Haemophilus somnus, Pasteurella, blackleg, and leptospirosis. Vaccines are of three types: replicating, non-replicating, and intra-nasal, which each have strengths and limitations. Ask us.


Bacteria + Viruses + Stress = BRD

Bovine respiratory disease, or BRD, commonly refers to infections of the lungs caused by bacteria that normally inhabit the nose and throat of cattle. Healthy lungs will have adequate resistance against the bacteria. Animals with lungs damaged by viral infection or animals stressed by management or environmental factors, however, will have a lowered resistance level. When a rapidly rising bacterial disease challenge is superimposed on a lowered resistance level, sickness can occur rapidly and severely.

Some of the stresses that contribute to BRD include exhaustion, starvation, and dehydration (often associated with shipping), weaning, ration changes, castration, dehorning, overcrowding, chilling, overheating, confinement in poorly ventilated quarters, and social adjustments associated with commingling cattle from different sources. The bacteria primarily involved with BRD are Mannheimia (Pasteurella) haemolytica, Pasteurella multocida, and Haemophilus somnus. We can help you design prevention and treatment strategies to help limit BRD.

Be Prepared for High-Risk Calves

Calves acquire immunity at birth, but it is lost as the animal matures. Newly weaned cattle (5 to 7 months of age, 450 to 650 pounds) have lost this immunity and are most susceptible to common feedlot diseases. These animals usually enter feedlots in the fall, when temperature fluctuations and dust are especially troublesome. If the cattle have a poor nutritional background, have parasite infestations, have not been exposed to common feedyard diseases (either naturally or through vaccines), or are shipped long distances, they are more likely to suffer severe disease problems during the first few weeks in the feedlot.

Scrupulous observation and attention to newly weaned cattle in the feedyard are the key to avoiding many problems.