Kerala, India
Crossbreeding does not provide an instant solution to all breeding challenges. Results prove disappointing with inferior parent stock quality or with breeds poorly adapted to environmental conditions. Successful crossbreeding programs require breeds contributing the optimal combination of economically important traits. For instance, producers marketing lambs should select ewes from breeds excelling in these characteristics:
- Reproductive performance.
- Appropriate breeding season timing and duration.
- Conception and lambing percentages.
- Milk yield.
- Maternal behavior.
Crossbred ewes possessing these attributes can then be bred to rams from different breeds for producing market lambs. Desirable ram breed traits include:
- Superior fertility.
- Growth potential.
- Carcass merit.
- Breeding aggressiveness.
Selection Process for Increased Fertility
- Identify lambs born as twins or triplets and choose replacement lambs from this population. Twin lambs from young ewes demonstrate greater twinning potential than twins from mature ewes.
- When additional replacements are necessary, choose single ewe lambs from young ewes.
- Choose rams that were twins or from ewes with superior twinning histories. Scrotal circumference should measure 28 cm for 12-month-old rams and 32 cm for mature rams.
- Ewe lambs displaying estrus are generally more fertile and achieve greater lifetime lamb production than ewe lambs not reaching puberty during their first year. Selecting early maturing ewe lambs also promotes early season lambing, which may benefit certain management systems.
Such crossbreeding programs achieve greatest success on farms where feed supplies are readily controllable and sheep represent a principal farm income source. Fine-wool breeds should form the foundation for developing any ewe breed intended for crossbreeding programs. These breeds demonstrate exceptional adaptation to New Mexico rangelands, yield the highest wool quality, are produced within the state, and possess out-of-season breeding capability.
When the goal involves accelerating market lamb production, introducing newer breeds such as Finnish Landrace may prove practical. If out-of-season breeding is unnecessary, medium-wool, white-faced breeds could provide satisfactory results. However, for market lamb production, breed ewes to rams recognized for growth potential and carcass desirability. Suffolk and Hampshire generally possess advantages in desirable characteristics.