Jeanne - Simme Valley
Well-known member
EVALUATION OF HETEROSIS EFFECTS ON HEIFER PREGNANCY
The objective of this Montana State Univ. study was to estimate breed and heterosis effects on heifer pregnancy. Reproductive records were collected on 651 purebred and crossbred females consisting of three breeds: Hereford, Simmental, and Tarentaise. Heifer pregnancy was defined as successful if her first calving record was at 2 years of age, but a failure if her first calving record was at 3 years of age.
Results showed that Simmental-sired females were the most likely and Hereford-sired females the least likely to calve at 2 years of age, with Tarentaise-sired females being intermediate. Comparison of maternal genetic effects revealed that females out of Tarentaise dams were the most likely and those out of Hereford dams were the least likely to calve at 2 years, with no estimation on females out of Simmental dams. Heterosis effects were favorable, indicating that crossbreeding will increase the percentage of females calving at 2 years of age
(From Beef Cattle Research Update, Michigan State University. McAllister et al. 2007. Proc., Western Section, ASAS).
The objective of this Montana State Univ. study was to estimate breed and heterosis effects on heifer pregnancy. Reproductive records were collected on 651 purebred and crossbred females consisting of three breeds: Hereford, Simmental, and Tarentaise. Heifer pregnancy was defined as successful if her first calving record was at 2 years of age, but a failure if her first calving record was at 3 years of age.
Results showed that Simmental-sired females were the most likely and Hereford-sired females the least likely to calve at 2 years of age, with Tarentaise-sired females being intermediate. Comparison of maternal genetic effects revealed that females out of Tarentaise dams were the most likely and those out of Hereford dams were the least likely to calve at 2 years, with no estimation on females out of Simmental dams. Heterosis effects were favorable, indicating that crossbreeding will increase the percentage of females calving at 2 years of age
(From Beef Cattle Research Update, Michigan State University. McAllister et al. 2007. Proc., Western Section, ASAS).
