Just when you think you’ve done everything you can to grow healthy, robust heifers and avoid health challenges such as respiratory disease and scours, there’s more: heifer mastitis. It can appear in your heifer pens earlier than you think. Exposure to mastitis-causing pathogens happens at several points in heifers’ lives, from birth to calving.

Research shows that up to 90 percent of the heifer population is likely to freshen with pre-existing intramammary infections.

You can’t afford to ignore this statistic.

Heifers with mastitis enter the milking herd with light or blind quarters, higher somatic cell counts (SCC), lower milk production, increased treatment and labor costs, and less milk.

Adding insult to injury, your fresh heifers represent the greatest opportunity for milk production in your herd. Mastitis infection decreases your opportunity to realize high-quality, high-volume milk in the tank.

Plus, clinical mastitis in first-lactation heifers not only affects productivity now but also in future lactations.

Controlling the damage of heifer mastitis can be difficult since heifers can easily come in contact with mastitis-causing pathogens throughout their pre-fresh life.

Exposure to pathogens can happen in the maternity pen, especially if pens aren’t thoroughly cleaned and freshly bedded between uses.

Calves also can be exposed to pathogens by suckling from infected fresh heifers or being fed colostrum or unpasteurized whole milk from infected fresh heifers or high-SCC cows.

Bacteria from infected milk can colonize in a calf’s mouth and be passed to other heifers through suckling or licking the flank or udder region on another heifer. Contaminated pen surfaces also can expose the teats of young heifers to more mastitis-causing pathogens.

Commingling can perpetuate the spread of mastitis-causing pathogens, both in your post-weaned groups and, later on, your calving close-up groups. Pre-fresh heifers are highly susceptible to mastitis infections and can be exposed when they’re commingled with older dry cows.

Flies also are leading culprits for spreading pathogens from infected cows to heifers. Flies thrive in warm temperatures and are attracted to areas where manure and feed build up.

Scabbing from fly bites can lock in bacteria, which can become embedded into the teat skin and enter through the teat end.

The power of prevention
Helping protect your pre-fresh heifers from mastitis infections starts with prevention and proactive management. Here are opportunities to help reduce mastitis exposure and support immune systems:

1. Reduce exposure early in your heifers’ lives. You might not think steps you take at birth or weaning will help reduce the likelihood of mastitis. However, proper management from the start can make a big difference in milk quality later in life.

Pre-weaned calves
• Separate fresh cows from newborn calves immediately after birth.

• Feed colostrum collected from healthy cows with clean udders.

• Pasteurize whole milk before feeding it to calves.

• House calves in individual pens or hutches.

Post-weaned heifers
• Monitor heifer pens for suckling and separate offenders.

• Keep pens clean and freshly bedded to help reduce exposure to environmental pathogens.

• Minimize the buildup of spoiled feed at the feedbunk.

2. Prepare your breeding-age and calving-age heifers for lactation. Keep a close eye on your heifers long before freshening to ensure they aren’t at risk for developing mastitis infections.

• Inspect teats for fly bites or excess scabs from fly bites.

• Watch for unusual udder swelling or leaking teats.

• House close-up heifers separately from close-up cows.

• Calve heifers in clean, freshly bedded pens.

3. Support pre-fresh heifer immunity with nutrition and vaccination. Mastitis control isn’t just for the parlor. Prevention efforts can start before your cows enter the milking string. Proactive management before freshening can help keep environmental mastitis at bay.

• Support heifers’ ability to fight mastitis by supplementing micronutrients such as selenium and vitamin E.

• Help reduce the severity and duration of environmental mastitis by vaccinating heifers against E. coli. Vaccinate cows or heifers at seven and eight months of gestation, followed by the third dose within two weeks postpartum, to help control clinical signs associated with E. coli mastitis.

Treat with caution
If you detect mastitis symptoms, such as swollen quarters and teat secretions, it’s prudent to work closely with your veterinarian to address these symptoms. Using a mastitis treatment for pre-fresh heifers constitutes an extra-label drug use.

This puts you at risk for violative residues, especially if the heifer calves early and fails to complete the dry period required by the product. Work with your veterinarian to devise a treatment program that’s safe for the animal and the food supply.

Don’t let the likelihood of heifer mastitis come between you and the productivity of your heifers. Know your risks and take proactive measures to reduce mastitis exposures.

This will help set up your heifers for successful first lactations and put high-quality, high-volume milk production within reach. PD

References omitted due to space but are available upon request. Click here to email an editor.

Bradley Mills
Veterinarian
Dairy Technical Services
Zoetis

Take a closer look at DHIA test sheets

When you review monthly DHIA records, how closely are you monitoring first-lactation heifers? The first two weeks of lactation are a critical observation period for detecting any pre-fresh heifer mastitis challenges. Here’s what to look for on your monthly test sheets and in your farm records:

1. Monitor the number of clinical mastitis flare-ups in fresh heifers.

• If more than 10 percent of your fresh heifers per year experience clinical flare-ups within the first two weeks of lactation, then a mastitis problem is highly likely.

2. Track DHIA data.

• Less than 21 percent of your herd should have a first somatic cell count greater than 200,000 and linear score greater than 4.0.

3. Culture clinical mastitis flare-ups.

• Notable Staphylococcus aureus infections may indicate a greater mastitis problem among pre-fresh heifers.