@conference {40557,
	title = {Prevalence of two inherited disorders in US Holstein cattle},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {54},
	year = {1994},
	month = {Jan},
	pages = {35-38},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The deficiency of uridine monophosphate synthase is a disorder of 
the de novo pathway for pyrimidine nucleotide biosynthesis.  Inherited as an  
autosomal recessive, it results in early embryonic mortality for the homozygous  
recessive genotype.  In the mid-1980{\textquoteright}s, heterozygotes were estimated at 1 - 2\%  
among US Holstein cattle.  The institution of a testing program for carriers and  
refusal by US artificial insemination companies to accept carriers into their  
progeny testing programs has eliminated the condition from the top 400 US  
Holstein bulls.  Bovine citrullinaemia is a defect of the urea cycle.  Also  
inherited as an autosomal recessive, it results in early postnatal mortality for 
the homozygous recessive genotype.  In 1990, heterozygotes constituted 0.3\% of  
US Holstein cattle.  At present, no known carriers are among the top 400 US  
Holstein bulls.  Carriers for either condition can be detected by convenient 
and inexpensive DNA based testing.  To guard against these conditions  
reappearing, a modest testing program among prominent US bulls should be  
continued and importers should insist that imported Holstein germplasm have  
no evidence of these conditions. },
	issn = {1176-5283},
	author = {Robinson JL and Shanks RD}
}
