Proceeding of Veterinary and Animal Science Days 2015, 15th- 17th  July,  Milan, Italy 

riviste.unimi.it/index.php/haf                                                                                 1 

   

 

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AD VAN VUUREN 

Ad van Vuuren obtained his 

degree in Veterinary Medicine at 

Utrecht University in 1974 and 

his PhD in Animal and 

Environmental Sciences at 

Wageningen University in 1993. 

Between 1975 and 2015, he was 

attached to Wageningen UR 

Livestock Research as scientist in 

the digestive physiology of 

ruminants. His main topics of 

study were rumen health, 

nitrogen utilization & 

environmental protection, and 

nutrition management & welfare 

of dairy cattle around calving. 

Ad van Vuuren managed a large 

variety of contract research 

projects commissioned by 

governments, industries or the 

European Union. He co-

supervised various MSc and PhD 

students in dairy cow nutrition 

at Wageningen and Utrecht 

University and (co-)authored 

more than 70 peer-reviewed 

publications and numerous 

other international and national 

papers and documents. He also 

contributed to various 

international and national 

scientific commissions as well as 

to advisory and editorial boards. 

Ad van Vuuren received the 

ADSA International Diary 

Production Award in 2004 and is 

diplomate of the European 

College of Veterinary and 

Comparitive Nutrition. 

Ad van Vuuren retired in June 

2015. 
 
 
ad.vanvuuren@upcmail.nl  

 

 

Confirmation Bias: Examples from Dairy 

Cow Nutrition and Their Impact on 

Evidence-Based Veterinary Medicine 
Ad VAN VUUREN 1 

1 
Archipel 1303, 8224 GA Lelystad, the Netherlands; 

 

MAIN LECTURE 

In 1989 a Boeing 737 crashed in the Amazon jungle after running out of fuel 600 
miles off course. The accident was due to human failures, being incorrect input of 
the required direction and misinterpreting external signals thereby 
(mis)confirming that the plane headed the right way and that the crew was 
infallible; a situation in psychology known as confirmation bias.Confirmation bias 
is the tendency to search for, interpret, or recall information in a way that 
confirms one's beliefs or hypotheses. Also in (Veterinary) Science external signals 
can be helpful to confirm one’s beliefs or hypothesis, but an open, critical attitude 
must be considered to prevent confirmation bias. Therefore veterinary (and 
other) nutritionists should:  
-utilise facts and insights obtained in well-designed experiments to develop sound 
unbiased theories on the aetiology of nutrition-based animal diseases and to 
generate preferable interventions to prevent or treat such diseases. 
-reflect on the effect of dogmas in dairy cow nutrition, which may have 
consequences for preventing for example laminitis and metabolic disorders in 
early-lactation. 
This brings to Evidence-Based Veterinary Clinical Nutrition whose development, 
advantages and disadvantages of Evidence-Based Veterinary Medicine (EBVM) 
have been reviewed recently (Vandeweerd et al., 2012). Similar to evidence-based 
medicine, EBVM distinguishes five sequential steps: (1) formulate answerable 
questions, (2) locate best evidence to answer the question, (3) assess internal 
validity of the obtained information, (4) integrate validated information with own 
clinical expertise and the unique situation of patient and owner and (5) assess 
effectiveness and efficiency of the therapy to improve future appraisals (Schmidt, 
2007, Fajt et al., 2009, Vandeweerd et al., 2012). In a contribution of Roudebush et 
al. (2004) examples for applying EBVM in clinical nutrition have been presented, 
showing how this approach can improve patient outcomes. Two examples will be 
analysed in detail: sub-acute ruminal acidosis and lipopolysaccharides as a cause 
of laminitis and postpartum low feed intake as a causes of metabolic disorders in 
early-lactation. 
We will see that to develop and update preventive and therapeutic interventions, 
a critical, unbiased approach is essential to deliver professional veterinary support 
to patients and owners coherent with the rapidly-evolving state of art. 

 

REFERENCES  
Fajt, V. R., D. Brown, and M. M. Scott. 2009. Journal of Veterinary Medical Education 
36(2):186-195; Roudebush, P., T. A. Allen, C. E. Dodd, and B. J. Novotny. 2004. Javma-
Journal of the American Veterinary Medical Association 224(11):1766-1771; Schmidt, P. 
L. 2007. Veterinary Clinics of North America-Small Animal Practice 37(3):409-417; 
Vandeweerd, J. M., N. Kirschvink, P. Clegg, S. Vandenput, P. Gustin, and C. 
Saegerman. 2012. Veterinary Journal 191(1):28-34. 

mailto:ad.vanvuuren@upcmail.nl