Two Breed Rotational Cross
A two breed rotation cross can result in a 15% increase in weight of calves weaned per cow joined.
This system requires two joining groups and two sire breeds. The daughters by sire breed A are mated to sire breed B and vice versa. It is very simple to introduce a two-breed rotational cross into a pure-bred herd. Simply divide the herd in two; buy a bull of a compatible breed and join him to half the herd. Join the original bull to the other half ofthe herd. The heifers from this joining will be joined to the bull of the other breed for the rest of their lives.
- Suits herds requiring two or more bulls.
- Uses two breeds of bull at the same time.
- Each sire breed is mated to the daughters of the other.
- Self replacing.
- Requires two mating groups.
- Some form of identification is required to determine sire breed.
- Breeds need to be of similar mature size to reduce calving difficulty.
- Suits vealer, store weaner or steer production depending on breed choice and environment.
Market: Suit store weaners, vealer production or steer or breeding female production.
Environment: Suit low-medium rainfall area 450-700 mm (18-27 inch) with improved pasture.
Three Breed Rotational Cross
A three breed rotational cross can lead to a 20% increase in weight of calves weaned per cow joined.
This system is similar to the two breed rotational cross only three bull breeds and three joining groups are required.
- Suits herds requiring three or more bulls. Uses three bulls at the same time.
- Requires three mating groups.
- Heifers by sire 3 are mated to sire 1; heifers by sire 1 are mated to sire 2; heifers by sire 2 are mated to sire 3.
- Self replacing.
- A good system of individual identification is required to determine sire breed.
- All breeds need to be of similar final size — to reduce calving difficulty.
Market: Suit vealer, store weaner, steer or breeding female production depending on environment.
Environment: Low-medium rainfall, improved or unimproved pasture.
Terminal crossing is the simplest crossbreeding system available. European sires are usually used in terminal crossbreeding systems. They transmit rapid growth and carcase characteristics to the calf which makes both the male and female calves excellent slaughter cattle. As all offspring are sold, a source of replacement females with good maternal characteristics will be required. The simplest terminal crossbreeding system involves buying either straightbred or crossbred replacement females.
If crossbred cows are used, this system will provide the greatest increase in production over a straightbred British herd because of its use of European bulls and crossbred British breed cows.
Some research sources have quoted increases in production of up to 30% with this type of crossbred herd.
- Suits a minimum herd size of 60 cows.
- Two bull breeds will be required if buying in heifers.
- A British breed bull will need to be joined to heifers and possibly second calvers to reduce calving difficulties.
- Suits vealer, store weaner or bullock production depending on environment.
Example: terminal cross herd
An alternative terminal cross herd is one which is combined with a self-replacing herd. The self-replacing herd will supply the replacement females required by both the terminal and self-replacing portions of the herd. Some 50-60% of the cows should be in the self-replacing herd to provide adequate numbers of replacement females for both herds.
- A straightbred or crossbred herd is required to supply the replacement females to the terminal herd.
- 120 cow herd (minimum).
- Use of European and British bulls.
- European cross females are sold because of their large size, high maintenance requirements and possibly low milk production of one European breed in particular.
- If using a straightbred herd to supply replacements, two herds or joining groups are required.
- If using a rotational crossbred herd to supply replacements, three herds or joining groups are required.
This system is far more complex than those mentioned previously and will require greater management input and commitment.
Example: Self-replacing and terminal cross herd
Market: Herd I and 2 — male calves, vealer production; female calves, replacement females. Herd 3 — store weaners suitable to be fattened to steers or bullocks.
Environment: Suit medium rainfall area 500-700 mm (20-28 inch) with improved pastures.