Dr. Mickelson, DVM
Dairy Calf Diarrhea - why are they at higher risk?
Young dairy calves (1- to 14-days-old) are unique because…….
- Their abomasums do produce high levels of hydrochloric acid needed to kill (or greatly reduce) ingested pathogens.
- Immunoglobulin A (IgA) is an important mucosal antibody and is not fully re-secreted into the gut lumen until they are about 2 weeks old.
- Dairy calves are fed twice, maybe 3x/day, whereas beef calves suckle about 6 times per day.
- Many dairy calves are fed about 10% of their body weight/day vs. beef calves that will nurse up to 25% of their body weight/day. Some farms are feeding dairy calves 20% of body weight (about 2 gallons a day, or 8 liters)
- They like to lick and suck on objects in their environment (boredom?, hunger?).
- Their ideal temperature (thermo-neutral zone) is 55 F.
- They produce little body heat and can not be relied upon to “heat” a barn.
- Their abomasums are about 3 times larger than their reticulorumens.
- They have almost no ability to digest fiber in their undeveloped rumen.
- Under ideal conditions, they can double their body weight in two months.
- When compared to older animals, young calves are the more efficient at turning feed into lean body mass.
- Like all small animals, they have a high body surface area to volume ratio.
- At 55 F, these calves have about 3 days of body fat reserves.
Cold weather and calf health considerations:
1. Washing typically stops during cold weather, especially calf huts.
2. Viruses (especially coronavirus), bacteria and parasites are preserved in cold environments.
3. Cold-stressed calves are hungry and nibble or chew on objects that have not been cleaned = Increased, persistent exposure.
4. Cold-stressed calves shed more pathogens and shed them longer than non-stressed calves = Increased exposure.
5. Water availability slows, or stops, during cold weather preventing adequate digestion of solid feeds promoting bacteria (Clostridium sp.) digestive upsets. It takes 4 lbs. of water to digest 1 lb. of feed. If a calf eats 2 lbs. of starter/day and some bedding, did it drink a gallon of water?
The problems in 1-5 “snowball” into a hateful mess of disease and pestilence that can’t be fixed with antibiotics, electrolytes, or anything else in a vet truck.