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Purdue Research Highlights More Reasons to Focus on Calf Health

Information from Dr. Jackie Boerman – Purdue University

For the past several years, at Purdue University, we have been researching the long-term effects of early life events for dairy calves. Our goal is to figure out what matters when it comes to raising calves to focus management in those areas. Below are some of the findings that provide compelling evidence to continue to focus on the health of those calves in order to make productive cows. 

  1. Respiratory disease and growth – animals that developed respiratory disease in early life weighed less than animals that were not treated for respiratory disease, even up to when animals were eligible to be bred. These effects may be dependent on the severity of disease, success of treatment, and environmental conditions on individual farms, but the results imply that respiratory disease when the lungs are developing can have long term effects on growth.  In a smaller subset of animals, animals that were identified as having lung damage from respiratory disease, as evaluated by lung ultrasounds at weaning, had reduced ADG during the pre-weaning phase. These animals that had reduced ADG did not consume any less milk, therefore they were less efficient, consuming the same amount of milk but growing slower.


  1. Respiratory disease and reproduction - animals that were treated for respiratory disease in the first months of life had reduced risk of getting pregnant by 16 months of age. While the cause cannot be defined from this observation study, slower growth may delay puberty in heifers and reduce the amount of time animals were eligible to become pregnant. 


  1. Respiratory disease and culling - animals that were treated for respiratory disease in the first months of life had increased risk of culling prior to their first lactation. All other factors being held constant, those animals that were treated for respiratory disease were less likely to become a lactating cow, increasing the heifer raising cost without producing a lactating animal. The increased risk of culling may be related to both reduced growth as well as reduced reproductive performance. Additionally, animals that were treated multiple times, had increased risk of leaving the herd compared to animals that were treated just once.

There are several other factors that impact growth, reproductive efficiency and risk of culling however, respiratory disease appears to have a large impact. Therefore management, nutrition, and genetic selection that positively impacts respiratory health, may have long term benefits for your herd. Please reach out if you have any comments or questions at

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