Crossbreeding- Is it a Good Option?
Long-term selection of dairy cattle for increased production has resulted in a decline in various functional traits including reduced fertility as well as concerns about soundness of feet and legs, resistance to disease, and overall shorter productive life. Some of those effects may be related to increased inbreeding and others due to unfavorable correlations of production traits to fitness traits. Crossbreeding is one way to eliminate inbreeding and to bring heterosis into a herd which could result in improved functional traits in that herd. There has been renewed interest in crossbreeding worldwide with use of both traditional and non-traditional dairy breeds. Some studies have documented up to a 10% economic gain in the F1 crosses. Holstein and Jersey crosses are popular due to the commonality of these two breeds. Those crosses generally have advantages in fertility, calving ease, neonatal survival, maintenance of body condition score, and are still competitive for milk yield and milk components. Holsteins have a higher milk yield, but Holstein X Jersey crosses produce milk with higher fat and protein content. Across time, 2-breed crosses maintain 67% of the heterosis of the original F1whereas 3-breed crosses maintain about 86% of the initial heterosis. Cows that have lower fertility or lack functionality otherwise lead to lost revenue, greater cow turnover, and simply do not last long term on a farm. Selection for improved fitness within breed is a good approach but crossbreeding may also be a strategy to improve the bottom line in some herds.
Heterosis, Inbreeding, Functionality