by Sally Colby
Backgrounding, which occurs between weaning and finishing, can be an important aspect of the cattle production process. Although cattle are managed in groups for backgrounding, there’s no single recipe for success.
While backgrounding provides timing flexibility for cattle going to market, this period involves more than simply waiting for the market to change. Facilities, feeding and health management are vital for success.
The backgrounder should be able to provide a balanced ration of grain, forage and supplements. In most cases, home-grown feeds are the key to profit in backgrounding. However, low-cost feed won’t make a difference in profit if cattle don’t gain, so it’s critical that rations provide steady weight gain.
With good management, calves are more likely to maintain good health. Dr. Daniel Pecoskie, who works with cow/calf operators and feedlot owners in Canada, said bovine respiratory disease (BRD) is the most common health issue in backgrounded calves, usually manifesting as pneumonia. BRD affects the upper airways or respiratory system, often involving both viruses and bacteria.
“BRD is a complex disease interaction,” said Pecoskie. “Common viruses involved are IBR, BVD, PI-3 (parainfluenza) and BRSV (bovine respiratory syncytial virus). Common bacteria involved in pneumonia are Mannheimia, Pasteurella and Histophilus.”
BRD is often associated with stress such as weaning, transport, co-mingling, poor air quality, overcrowded pens, sudden weather changes (temperature, humidity) and sudden changes in feed. Interactions between pathogen load, the calf’s environment, host resistance and the causative virus and/or bacteria all influence calf health.
Pecoskie described the calf with BRD as having a wet cough, increased respiratory rate, fever, shallow breathing, outstretched neck (to get more oxygen), depression and unwillingness to come to the feed bunk. Cloudy nasal discharge usually indicates bacterial infection, while viral infections manifest with clear mucous.
Cases of BRD in backgrounded calves typically peak in the first seven to 10 days after stressful events. “Stress puts strain on the immune system and calves’ immune responses can be overwhelmed,” said Pecoskie. “Some immune responses help fight disease, like mucous production and coughing, that get pathogens out of the airway.” Non-specific cells work in the lungs and bloodstream to kill bacteria and viruses, but viral infection tends to dampen the effects of natural immune responses. When the immune system is knocked down, secondary bacterial infection sets in.
Disease prevention involves a combination of measures including vaccination, low stress weaning, pain management at castration and dehorning, allowing time for calves to adjust to the bunk and deworming. Some producers administer a long-acting antibiotic labeled for BRD upon arrival to the feed yard to help prevent disease.
Pecoskie said the goals of vaccination are to prepare calves for times of stress, reduce susceptibility to infection and develop a faster immune response to BRD pathogens. “Vaccinating doesn’t eliminate the need to treat animals,” he said. “Hopefully we reduce the severity of the virus or bacteria. A faster immune response comes from the more specific immunity that we’re developing with the vaccine.”
Vaccines for disease prevention are either modified live or killed. “Both stimulate antibody production,” said Pecoskie. “The body will produce antibodies to attack the bacteria or virus it’s infected with. The difference is modified live viral vaccines stimulate another arm of the immune system – the cell mediated immune response – which generates longer ‘memory’ in the attack cells.” Killed vaccines can also provide good immune response but require a booster, which requires running cattle through the chute a second time.
Modified live vaccines provide good immunity with a single dose. These vaccines are mixed prior to use, and once mixed, the entire bottle should be used the same day. If stored properly, partial bottles of killed viral vaccines can be stored and used within a certain timeframe.
It’s important to store and administer vaccines properly for optimum effectiveness, including storage in a cooler until the time of use, clean syringes, sharp needles and proper dosage at the correct administration site.
Pecoskie recommended vaccinating calves with modified live vaccines three to four weeks prior to exposure to a planned stressful event such as weaning, transport or castration. Killed vaccines can also be administered several weeks prior to stressful events, followed by a booster at weaning.
Understanding coverage is important. Five-way vaccines for protection against viral infections usually include IBR, BVD 1 & 2, PI-3 and BRSV. “Often the five-way viral vaccines come with a bacterin component,” said Pecoskie. “The bacterins protect against respiratory illness (Mannheimia, Pasteurella) by exposing calves to a non-virulent form of the bacteria to allow them to mount an immune response.” Clostridial vaccines protect primarily against blackleg, tetanus and enteritis. Pecoskie said calves often appear dull for a few days following vaccination but bounce back quickly.
“Vaccination itself does not necessarily equal an immune response in the calf,” said Pecoskie. “The goal of the vaccine program is to reduce the risk of bacteria and viruses causing pneumonia. There may still be a few [calves] that break with disease depending on whether they’re overwhelmed by stressors. Vaccines reduce the incidence of disease, the number of head you pull and severity of pneumonia.”
In addition to vaccines, disease prevention involves pen management. Clean, dry bedding, windbreaks or shelters, access to fresh water, good ventilation and appropriate stocking density all contribute to helping calves fight disease.
Once calves are vaccinated, weaned, grouped and started on a ration, it’s important to conduct routine pen checks to catch illness early. Pecoskie suggested checking cattle at least once a day, particularly at feeding time. “I like to start with group inspection from a walkway or over the fence,” he said. “It’s a chance to look at the entire group undisturbed. Sometimes that involves seeing which animals are coming up at feeding, which animals are toward the back showing signs of depression.” When entering the pen, approach slowly and move with the group but look at individuals to determine whether any animals are showing signs of illness.
“Start by walking the perimeter of the pen,” said Pecoskie. “Follow the paths they’ve generated. Get animals to stand up and watch as they walk away.” Being aware of the natural flight zone helps a handler assess animals in the pen. Healthy animals will walk away then look back when they’re far enough away, while sick animals tend to continue moving slowly forward and away from pressure. Trembling, weakness or overall slowness indicate illness, and these animals should be pulled for a temperature check and further assessment. When sick animals are identified, producers should not delay following protocols developed with the herd veterinarian.
Good records help both the producer and vet track trends and develop treatment protocols. Pecoskie recommended post-mortem exams of animals that die suddenly to ensure future diagnoses and treatments are timely and appropriate.
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