Scours and respiratory disease in young calves are linked.
In a May 26, 2019 Hoard’s Dairyman article Dr. Ollivett (University of Wisconsin School of Vet. Med.) says “Young calves with diarrhea are much more likely to develop pneumonia than their herdmates that did not experience diarrhea.” By improving gut heath we can expect to see fewer treatable cases of respiratory illness.
She observes “Often, abnormal manure is overlooked if the calf is not off feed or depressed. When you spend time specifically looking at fecal consistency, you might realize you have more of a problem than you thought.”
Especially where pneumonia issues are serious among 3 and 4 week-old calves, Dr. Ollivett recommends serious-level record keeping on diarrhea among 1 and 2 week-old calves.
She notes that measuring weight gain during weeks 1-2 may reveal that intestinal health is not ideal. It is “normal” when calves receive adequate nutrition that they begin gaining weight before the end of the first week. If your calves are not gaining weight or losing weight by 14 days of age you may have found one of the causes of pneumonia in the subsequent weeks.