@conference {40631,
	title = {How relevant are current and emerging genetic technologies to the beef breeding cow?},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {337-344},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The genetic merit of stock in the commercial sector of the beef breeding  
herds is dependent on the rate of genetic gain in nucleus herds and the length of  
delay it takes to transfer this genetic gain to commercial herds.  This paper  
states the factors controlling the rate of genetic gain and genetic lag and  
examines the impact of current and future technologies on these factors.  The  
setting of selection objectives and opportunities for crossbreeding in New  
Zealand beef breeding herds are also mentioned briefly. 
 
The maximum theoretical rate of genetic gain in beef cattle herds is about  
3.4sigmaT (genetic standard deviations).  Current technologies should allow a rate  
of gain of about 0.25sigmaT but results from New Zealand beef cattle selection  
experiments suggest that the actual rate achieved in the industry is unlikely to  
exceed 0.1sigmaT.  It is suggested that many new technologies becoming 
available will either have little impact on the rate of genetic gain or will be 
too expensive to apply in New Zealand{\textquoteright}s extensive beef cattle industry.  
Opportunities will exist for nucleus breeders who are prepared to cooperate with 
each other giving them a larger pool of breeding cows. 

The most likely genetic lag using current practices is about 10 years in the New  
Zealand beef cattle industry.  By generating replacement females from only  
young parents and by accessing sires of above average genetic merit, it should  
be possible to reduce genetic lag to about 1 year. 
 
It is concluded that the New Zealand beef cattle industry could greatly enhance  
the rate of genetic gain and reduce the level of genetic lag through the  
application of existing technology.  Furthermore, the establishment and  
application of sound selection objectives is an immediate priority. },
	issn = {1176-5283},
	author = {Blair HT and Garrick DJ}
}
