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Posted: 10/04/2022


How Weather Changes Bring Wellness Concerns for Calves

Farmers know when the temps fall, the susceptibility for illness among their herd rises. Even though livestock can tolerate the cold, the changing weather opens them up to potential respiratory illnesses and scours. These can be especially problematic in calves that were just born, and have the potential to wreak havoc on both physical and economical health of the operation. As the changing weather approaches, we want to equip you to combat the stress and increased bacteria that may infiltrate your herd.


Husband and wife dairy farmers standing near barn

How Does Cold Weather Affect Cattle?

Environmental factors of all kinds can stress the herd, with weather changes chief among them. But external conditions are only half the story. Internally, cattle contend with multiplying germs this time of year. Bacteria in the nose is common for healthy cattle, but research shows that bacterial populations in calves’ noses are as much as seven times greater when they’re exposed to colder weather.

These germs invade the lung tissue and lead to inflammation, fever, cough and decreased appetite. Calves that get treated for respiratory disease will as dairy cows produce 10 percent less milk in their first lactation and 15 percent less milk in their second lactation. Understanding – and preventing – these diseases ahead of time will help keep your profits more predictable than the ever-changing temperatures.

Bovine Respiratory Disease Complex (BRDC)

BRDC is the most devastating disease of the U.S. cattle population. It’s a complex because it comes from a mix of causes including bacteria, stress, nutrition, viruses, and more. It impacts cattle of all ages, but pay close attention to stressed calves during the weather change.

A Variety of Viruses

Here are the key viruses that contribute to BRDC:

  • Bovine parainfluenza virus (PI3)
  • Infectious bovine rhinotracheitis (IBR)
  • Bovine respiratory syncytial virus (BRSV)
  • Bovine viral diarrhea (BVD) virus
  • Bovine coronavirus (BCV)
Symptoms for these viruses regularly include fever (an early sign of BRD complex), and may include watery eyes, depression, lack of appetite, nasal and/or eye discharge (water, puss and/or blood), rapid breathing and coughing. If the cough reaches a “honk” stage, the calf has an advanced illness.

Pneumonia in Cattle

When bacteria multiplies in the upper respiratory tract (often with PI3, IBR and BRSV), it has a better chance of reaching and infecting the lower lung with pneumonia. A cow’s mucus gets thick in the cold, and prevents the airway from cleaning itself of bacteria as it normally would.

Pneumonia symptoms often start with lower feed intake before progressing to a fever higher than 39.5 degrees C, nasal discharge, coughing and labored breathing. Thick and cloudy discharge means the animal is definitely infected. At the critically ill level, the calf is struggling for oxygen and will have badly damaged lungs if it survives.

We’ve got many broad spectrum antibacterials to consider for treating bacterial pneumonia. Your veterinarian can also prescribe drugs for calves with pneumonia, but know that different bacteria require different drugs. That means failed treatments could require vets needing a bacterial culture from the calf to know what antibiotic to choose.

Cattle Vaccine Comparison Chart

One of the best ways to prevent illness and protect your herd is with vaccines. The experts at PBS Animal Health created a Cattle Vaccine Comparison Chart to help farmers pick vaccines that are right for your animals. Look to the chart to see some of the viruses mentioned above and find a specific list of vaccines that work to prevent them. The chart even provides dose, route of administration and slaughter withdrawal for each comparison between vaccine products.

The Bovilis Nasalgen 3 Cattle Vaccine is made for healthy cattle 1 week of age or older to prevent IBR, BRSV and PI3. Check with your certifier because this vaccine may be suitable for use on Organic Farms. The CattleMaster GOLD FP 5 L5 Vaccine offers similar protection, plus it covers the 5 most common strains of Leptovirus. CattleMaster GOLD is safe for any cow, any calf, any time, except within 21 days prior to slaughter. Look for both of these products and many others on our convenient comparison chart.


Protect Against Scours

Stress from the cold or other adverse weather conditions can bring on another health threat: calf scours. It’s the primary cause of death in calves from 2 to 30 days old, so it’s critical to keep close watch over fall-born calves especially.

Scours presents itself via watery stools, weak and depressed calves, dryness to mouth and nostrils, sunken eyes, and calves that stagger or sway as they walk. Pathogens in the calf’s intestinal tract prevent the absorption of fluids, leading to dehydration, acidosis and loss of electrolytes.

There are plenty of drench solutions, boluses, and liquids that treat non-infectious scours brought on by weather changes. Because the impact of scours far outlasts the early days (playing a role in lifetime production), many producers agree it's far more economical to invest in scours prevention altogether. ImmuCell's First Defense products give your calves guaranteed levels of specific antibodies that have been proven to protect against scours. Instead of vaccinating the dam and hoping she passes on immunity to her calf, First Defense offers a much more direct approach by administering antibodies to the calf at birth. Learn more about the entire line of First Defense products we carry.

Can Humans Get Scours?

Yes, humans are at risk of contracting scours so take caution when handling calves up to a month old because they can certainly make you sick. Anyone with a compromised immune system is more vulnerable and can have a stronger reaction. Symptoms in humans could present as severe diarrhea, stomach and other muscle cramps, dehydration, vomiting, fever and headache.


Other Solutions to Prevent Illness in Your Herd

Good colostrum, vaccines, and deworming programs lay the solid foundation to help prevent illness. As time passes, the animals adjust to the cold but we can help with that adjustment by offering shelter on extreme temperature days. We can also provide a windbreak for cattle to find protection from the wind. This could be as simple as a fence screen or a portable U-shaped partition, or as elaborate as an independent structure, as long as it gives the herd a shield when they need it. Finally, pay attention to nutritional needs. Cattle use more energy to regulate body temperature in the cold, so they often need more feed, or a different balance of nutrition to keep consistent weight gain.


PBS Animal Health Won't Leave You Out in the Cold

Don’t wait for temps to drop – get those calves ready now. Evaluate your herd’s vaccination status and environmental challenges, then turn to PBS Animal Health to fill in the blanks before Mother Nature takes a toll.

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