Flight Speed Culling

Summary

The cattle industry has long recognised the benefits of having cattle with good temperament.  The perceived benefits include:
Reduced handling costs eg mustering and processing in the yards
Reduced damage and therefore repair costs for fencing, yards etc.
Reduced risk to handlers
Probable improved performance eg growth rate
Probable improved meat quality.
However, in the past, the absence of objective measures of temperament has prevented proof that these outcomes are in fact real, and reduced the potential rate of progress made through selection.  For example, an industry survey conducted in 1994 showed clearly that industry saw the value in having quieter cattle, but was addressing the issue by clling nimals with obviously poor temperament, rather than selecting animals with better temperament.  It is well known that the rate of genetic change in any trait is much greater when a small number of superior sires is selected from the top end of the normal distribution curve, rather than just culling the group that are at the bottom end of the normal distribution curve.  
The majority of studies which have looked objectively at the association between temperament and feedlot average daily gain (ADG) have been conducted from the late 1990s to present, including the work of Burrow & Dillon (1997), Voisnet et al (1997a), Fell et al (1999), Petherick et al (2002) and Colditz et al (2006).  Most focus has been on performance in the feedlot, however work conducted by Fordyce et al (1985, 1988) under pasture conditions showed that Bos Indicus crossbred cattle with a quiet or calm temperament (based on crush score), had higher liveweights on pasture.  However, it is widely recognised that the differences are much less likely to be apparent under more extensive conditions ie less interactions with humans and infrastructure (potential stressors).
Collectively the results from the feedlot performance work confirm that cattle with poor temperament (as measured by short flight time or high crush scores), grow at slower rates during feedlot finishing.