@conference {40764,
	title = {A computationally feasible test day model with separate first and later lactation genetic effects},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {56},
	year = {1996},
	month = {Jan},
	pages = {19-21},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {In a two step analysis test day effects were estimated within herd with  adjustment for across herd effects and then the adjusted data were analysed  across herd. Genetic effects were defined for each of 10 months in milk  within first and later lactation and for milk, fat and protein giving 60 traits.  The rank of the genetic (co)variance matrix (G) was reduced to 6 such that  G retained the information to evaluate the selection objective. A  repeatability model allowed for multiple lactations with each lactation,  conceptually, expressing all 60 traits, but missing observations for 30 or  more. A canonical transformation was applied to create uncorrelated traits.  Missing values were replaced by their expectations at each round. Because  of the rank reduction, only 6 canonical traits were solved for. This system  should make evaluations more stable by removing biases due to genetic  differences in persistency and rate of maturity. },
	issn = {1176-5283},
	author = {Wiggans GR and Goddard ME}
}
