Weaning weight field records, supplied by the American Polled Hereford Association, were used to examine sire X environment interactions. Sire X herd/region and sire X contemporary group/herd interactions were evaluated from a data set containing 19,503 records. Sire X region interaction was evaluated from a data set containing 8,659 records. The genetic correlations of sire progeny performance across contemporary groups/herd were .59 and .37 across herds and contemporary groups/region. The average genetic correlation of sire progeny performance across regions was .64. Heritability of weaning weight was .11 across regions, .17 within region and .28 within herd. Mixed-model sire analyses of Polled Hereford weaning weight field records should include sire X herd/region and sire X contemporary group/herd random effects to reduce the sire X environment effects particular to any herd or contemporary group, and to account for the distribution of sire progeny across herds and contemporary groups in the estimation of prediction error variance. It may be necessary to perform separate sire analyses for some regions to evaluate the breeding values of sires in regions where rank changes are likely to occur.

The purpose of this essay is to develop a historic perspective of the beef cattle population and the legion of people directing its genetic change so that future leadership can increase the rate of breeding technology assimilation. Use of cattle for beef to feed millions is relatively recent. The beef industry of the United States has a rich, romantic heritage that combined Spanish exploitation with British tradition. Spanish cattle became adapted as the Texas longhorn and the European cattle became indigenous. Breeds developed in Britain replaced both. The Zebu was introduced to produce cattle adapted to the Gulf Coast. Selection for early maturity in the British breeds promoted by livestock shows was ended by the dwarf gene. The Charolais breed demonstrated growth potential. Then in 1967, Continental European breeds were imported, given an array of biological types from which to select. Beef cattle breeding research expanded after the second world war through the three regional projects. Performance Registry International was the focal point for performance. The Beef Improvement Federation produced guidelines for recording beef performance including those for national sire evaluation. U.S. Meat Animal Research Center evaluated the several newly introduced breeds. To date, breeding researchers have developed breeding technology for the use by breeder. The major breed association are keeping and utilizing performance records. The genetic structure of the beef breeds is being altered by the use of AI such that genetic change can be made rapidly by the use of superior sires evaluated on their progeny in many herds.

Variance components were estimated from field-collected performance records for use in national beef sire evaluation mixed-model programs. Estimates of residual error variances (sigma 2e), sire effect variances (sigma 2s) and dam effect variances (sigma 2d) were obtained for the American Hereford and the American Angus breeds for each of three growth traits: birth weight, weaning weight and postweaning gain. Estimates obtained for birth weight were sigma 2e, 8.43 and 9.26 kg2; sigma 2s, 1.34 and .66 kg2; and sigma 2d, 3.24 and 3.70 kg2 for the Hereford and Angus breeds, respectively. Estimates obtained for weaning weight were sigma 2e, 438.09 and 267.38 kg2; sigma 2s, 20.37 and 17.13 kg2; and sigma 2d, 162.25 and 157.28 kg2 for the Hereford and Angus breeds, respectively. Estimates obtained for postweaning gain were sigma 2e, 425.75 and 374.33 kg2; sigma 2s, 20.08 and 16.49 kg2; and sigma 2d, 41.74 and 48.61 kg2 for the Hereford and Angus breeds, respectively.

The Japan Racing Association (JRA) operates 10 national racecourses with both turf and dirt tracks. JRA formulates the rules for horseracing; registers owners, colors, and horses using foal registration; and licenses all JRA trainers and jockeys. In 1990, at the 10 racecourses there were 288 racing days, 3,353 races, and some 38,397 horses. Horse breeding is concentrated in 7 locations with 93% of the Thoroughbreds foaled each year coming from Hokkaido. Thoroughbred flat racing comprise 92% of all races held. Two year olds race together and nearly 40% of their races are run at 1200 m. Some 39% of the three year olds races are at 1800 m. For 3 (and 4) year olds, the range in distances is from 1000 m to 3600 m. The average, over years, of the number of race records per race for 2 year olds is 10.0 and for 3 year olds and up is 11.3. The average for race records per horse for 2 year olds is 3.5 and for 3 year olds and up is 6.7. This average for horses raced per year for 2 year olds is 1,164 and 4,240 for 3 year olds and up. Horses raced per sire averaged over years was 4.6 for 2 year olds and 10.5 for the older ages. The linear regression of seconds per 100 m fit the average seconds reported for the several distances run almost perfectly with R(2) values greater than .99 for all horse ages on either turf or dirt. There is selection practiced as indicated by horse numbers registered and their numbers over ages for stallions and mares. Less than .2% of the horses raced are geldings. A high degree of control exists by JRA in horse stabling and distribution of racing by horses over racecourses. Jockeys are trained by JRA, ride at several race courses, and ride for many trainers. ZUSAMMENFASSUNG: Genetik der Rennleistung beim Japanischen Vollblut: I. Beschreibung der Daten Die "Japan Racing Association" (JRA) betreibt in ganz Japan zehn Pferderennbahnen sowohl mit Rasen- als auch mit Sandkursen. JRA legt die Regeln für Pferderennen fest, registriert die Eigentümer, Farben und Pferde mittels Fohlenregistrierung und vergibt die Lizenzen für alle JRA-Trainer und -Jockeys. Im Jahre 1990 verzeichneten die zehn Pferderennbahnen 288 Renntage, 3353 Rennen mit 38 397 Pferden; Pferdezucht ist an sieben Orten konzentriert, wobei 93% der Vollblutfohlen aus Hokkaido stammen. Bei 92% der veranstalteten Rennen handelt es sich um Nichthindernisrennen von Vollblutpferden. Dabei stehen die Zweijährigen im Wettbewerb, und fast 40% der Rennen gehen über 1200 m. Etwa 39% der Dreijährigen nehmen an Rennen über 1800 m teil. Bei den Dreijährigen (und Vierjährigen) liegen die Distanzen zwischen 1000 bis 3600 m. Der Durchschnitt der Zahl der Rennmeldungen über mehrere Jahre für die Zweijährigen beträgt 10,0 und für die dreijährigen und älteren Pferde 11,3. Der Durchschnitt der Rennmeldungen pro Pferd bei den Zweijährigen beträgt 3,5 und den dreijährigen und älteren Pferden 6,7. Durchschnittlich nehmen jährlich an Rennen 1164 zweijährige und 4240 dreijährige und ältere Pferde teil. Die durchschnittliche Zahl der Pferde über mehrere Jahre war 4,6 ...

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