Rethinking Calf Care

With antimicrobial resistance on the rise, dairy producers are looking hard at alternatives to routine antibiotic use. Calf diarrhea is a prime example: it’s still the leading cause of sickness and death in preweaned calves, and most cases aren’t bacterial to begin with.

The answer may not always be another drug. Colostrum supplements, long relied on for passive transfer at birth, is proving its worth again—this time as a supportive therapy when diarrhea strikes.

Prevention still comes first: good colostrum at birth, strong hygiene, and low stress. But when scours show up, supportive therapy matters just as much.

Bovine Colostrum in Action: Research Findings

A study at a commercial calf-raising facility in Southwestern Ontario (Carter et al., 2021) tested colostrum supplementation at the onset of diarrhea. Calves were assigned to three groups:

• Control (CON): milk replacer only

• Short-Term Colostrum (STC): colostrum-milk blend for 4 feedings over 2 days, then milk replacer

• Long-Term Colostrum (LTC): colostrum-milk blend for 8 feedings over 4 days

Results were clear. Compared to the CON group, calves in the LTC group:

• Cleared diarrhea twice as fast

• Gained an extra +98 g/day on average

• Weighed +4 kg at day 42 and +6 kg at day 56 post-enrollment

Why? Colostrum is packed with antibodies, growth factors, nutrients, and natural antibacterial activity. It helps repair gut lining, supports immune function, and restores balance—without wiping out microbial diversity the way antibiotics can (Carter et al., 2021).

The Limits of Antibiotics

Most calf diarrhea is viral or parasitic, not bacterial. That means antibiotics often don’t work, and worse, they can disrupt the gut microbiome.

Studies show antimicrobial use can cut microbial diversity and slow immune development (Urie et al., 2018; Oultram et al., 2015). Fluid therapy remains the cornerstone—hydration prevents dehydration and keeps calves alive.

Colostrum alongside fluids adds a natural recovery boost without long-term downsides.

What Producers Should Do

• Prevention is still the base layer: Aim for ≥300 g IgG within 8 hours of birth, plus clean, low-stress housing.

• Act fast with supportive care: Isolate scouring calves, rehydrate, and monitor closely.

• Use colostrum beyond birth: Deploy it during diarrhea events, not just the first feeding.

• Work with your vet: Tailor protocols for safe, effective results.

Final Word

Colostrum isn’t just a newborn feed—it’s a flexible, proven tool for managing calf diarrhea. Used as both prevention and therapy, it reduces antibiotic dependence, improves calf performance, and supports healthier, more resilient herds.

For today’s dairies, that’s more than good animal care—it’s a step toward long-term sustainability.