The first phase of this s tudy was the production of contemporary straightbred (SB) and reciprocal crossbred (F 1 ) bulls by mating Angus (A) bulls to A and Santa Gertrudis (SG) cows and SG bulls to SG and A cows. Of the bulls produced during the 4-yr period, those used for breeding included 15 A, 15 SG, 8 A x SG and 8 SG x A. For 205-d weight and weight /day of age (W/DA) postweaning, A X SG h...

Selection practices in three synthetic lines of beef cattle were evaluated based on data collected over 12 to 13 years. Sires from the Jersey, Angus and Simmental breeds were mated to three lines of foundation crossbred dams to produce first generation progeny. Subsequent calves were produced mating crossbred parents of the same generation. Crossbred sires were selected based on an index that i...

Accurate pedigree information is critical to animal breeding systems to ensure the highest rate of genetic gain and management of inbreeding. The abundance of available genomic data, together with development of high throughput genotyping platforms, means that single nucleotide polymorphisms (SNPs) are now the DNA marker of choice for genomic selection studies. Furthermore the superior qualitie...

The objective of this study was to determine the relationships among daughter clinical mastitis during first and second lactations and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Data on clinical mastitis during first lactation were available for 1795 daughters (in six Pennsylvania herds, one Minnesota herd, and one Nebraska herd) o...

Lethal recessive genes that cause early embryo loss are difficult to detect. Nonreturn rate at 70 d after first insemination (NR) was evaluated as a trait of the embryo using 1,739,055 first-service records from 1,251 Holstein bulls represented as both service sires and sires of cows. Effects modeled included herd-year-season, parity of cow, sire of cow, service bull, interaction of service bul...

International genetic evaluation of dairy sires is currently a two-stage process. Sire EBV are first calculated at the national level based on data of local progeny, then these national EBV are combined into international EBV at the Interbull Centre. However, differences in within-country procedures for data collection and genetic evaluation can affect the results, and traits or production envi...

Appropriate parental care by fathers can greatly facilitate healthy human family life. However, much less is known about paternal behavior in animals compared to those regarding maternal behavior. Previously, we reported that male ICR strain laboratory mice, although not spontaneously parental, can be induced to display maternal-like parental care (pup retrieval) when separated from their pups ...

Test day SCC records were obtained from the Ontario DHI and converted to somatic cell score using a logarithmic transformation. Adjustment factors for stage of lactation and calendar month were obtained for first and later lactations. Effects of stage of lactation were significant and followed a systematic pattern. Seasonal effects were small. Sire estimated breeding values for lactation mean a...

Seventy-seven polymorphic microsatellites were analysed in offspring of three elite sires that were part of the foundation of an experimental population selected for twinning rate at the US Meat Animal Research Center, Clay Center, Nebraska. All females were assessed for ovulation rate by rectal palpation of corpora lutea over 8-10 consecutive oestrous cycles from approximately 12 to 18 months ...

Maternal inputs to offspring early in development are initially high but the process of development suggests that ontogenetic shifts in the importance of maternal genetic variation relative to other sources should occur. We investigated additive genetic variance and covariance for direct (animal), sire, and maternal effects on embryonic length (EL), yolk sac volume (YSV), and alevin (after yolk...