The liveweights of 100 females sired by Holstein (H), Jersey (J) or Brown Swiss (BS) bulls out of Holstein-Friesian x Gir dams of 1/2 to 3/4 Holstein-Friesian fraction were compared. The animals were kept in a single herd under the same management. The data were analyzed separately for four age categories by least squares techniques. The models for cows and heifers older than 18 months included...

Binary variables arising from an underlying normal distribution with a fixed threshold were simulated in a two-stage selection scheme with a sire model. The model had herd-year-seasons and groups as fixed effects and sires as random variables; a heritability of .25 was used in the simulation. The "best" 20% of the sires were allowed to have additional progeny in the second stage. The criteria u...

The effects of heterogeneity of variance among herds on dairy sire evaluation were examined. Data consisted of 111,196 first lactation Holstein production records of heifers calving in Ontario between 1978 and 1983. To account for selection, older sires without first crop daughters in the data were treated as fixed effects. Herds were classified into one of nine groups based on their estimated ...

The nature of the heterogeneity of variance for 200- and 365-d weights by sex, sire breed, and dam breed subclasses was studied. Data consisted of records for weaning (n = 7,829) and yearling (n = 7,367) weights of progeny from 673 and 672 sires, respectively, from 22 breeds that have been evaluated in the Germ Plasm Evaluation Program at the U.S. Meat Animal Research Center, Clay Center, NE. S...

Flocks participating in sire referencing schemes can achieve greater genetic gains than those achievable by within-flock selection. However, requirements for joining these schemes can be prohibitive to some producers. The objectives of this study were to determine whether less restrictive schemes or schemes of shorter duration could achieve rates of gain and reduce inbreeding as efficiently as ...

Gestation length, birth weight calving difficulty, calf mortality rate at birth, calf mortality rate from birth to weaning, preweaning calf growth rate and calf 200-d weight were evaluated in a biological type study in which four sire breeds were bred by AI to Hereford dams. Angus and Red Poll sires represented breeds of medium size, and Pinzgauer and Simmental sires represented large breeds. A...

The objective of this study was to compare weight and quality of fleeces of different F1 ewe types produced from breeds with a broad range of fleece types. Weights of 629 fleeces produced during 1988 through 1991 from F1 ewes that were daughters of Suffolk and Targhee dams and Finnsheep, Combo-6, Booroola Merino, St. Croix, and Barbados sires were recorded. Staple length was measured on the mid...

Individual lactation records from Holstein cows in 3449 herds participating in an AI stud's young sire sampling program from 1971 to 1987 were used to characterize the sampling program and to estimate genetic merit and trend. Average genetic merit of cows in sampling program herds was consistently superior to the average genetic merit of cows in the US population. Genetic trend of sires of firs...

Adjustment factors to allow comparison of EPD from several breed associations for birth, weaning, and yearling weights have been available for more than 10 yr. This paper describes steps to calculate adjustment factors for EPD for 4 carcass traits: marbling score, fat thickness, ribeye area, and retail product percentage. The required information is the same as for the weight traits: 1) breed o...