Animal Sciences Commons^™

Contemporary Grouping In Mixed-Size Dairy Herds Experiencing Four Seasons, Mohammad Ali̇ Nilforooshan

Turkish Journal of Veterinary & Animal Sciences

Countries with different herd structures and climates use different combinations of herd, year, and season to define the effect of their climatic conditions and management. Estimates of variance components and Akaike information criterion values resulting from 8 analytical models differentiated by different combinations of herd, year and season effects were compared for milk and fat yields. Data consisted of pedigree and records of 11,850 Holsteins freshening in 38 dairy herds of Isfahan, Iran, between January 1994 and October 2001. Heritability estimates were lowest for the models that used herd-year combination as a random effect. Moreover, the use of these models …