
%0 Journal Article
%A Herron, ND 
%A Pattie, WA 
%T Studies of the Australian Illawarra Shorthorn breed of dairy cattle. II.* Genetic analysis
%J Australian Journal of Agricultural Research
%D 1977/12/01
%V 28
%N 6
%P 1119-1132
%K 
%R https://doi.org/10.1071/AR9771119
%U https://www.publish.csiro.au/paper/AR9771119 
%X A genetic analysis of the Australian Illawarra Shorthorn breed of dairy cattle has shown that the most important herd in 1973 made a genetic contribution to the breed of 29.5&#37; and the next most important herd contributed 27.9&#37;. The 12 most important herds combined contributed 70.5&#37;. The sire with the highest relationship to the breed was 'Jean's Monarch of Blacklands' with direct relationships of 3.5, 4.0, 7.5 and 10.9&#37; to the 1938, 1949,1960 and 1973 samples respectively. 'Sunny View Little Princess 30th' was the dam with the highest relationship to the breed with direct relationships of 0.5 and 8.6&#37; to the 1960 and 1973 samples respectively. From 1930 to 1973 inbreeding increased a total of 7.6&#37;. This comprised 1.6&#37; current inbreeding and 6.0&#37; non-current inbreeding. Strain inbreeding was at its maximum in the 1949 sample (2.02&#37;) but had disappeared by 1973. The effective generation length was 5.23 years. Of animals in the 1973 sample, 72&#37; were sired by bulls 5 years old or younger, while 50&#37; of animals were from dams 4 years old or younger. It is shown that the bull requirements of the breed could be met by the progeny of performance-recorded animals.  _________________ *Part I, Aust. J. Agric. Res., 28: 1107 (1977). 
