Cross-breeding and artificial insemination

Taruvinga Magwiroto

If you are interested in moving your cattle business towards commercialisation or farming as a business, you will be concerned with ways of improving the performance of the herd. By performance I mean conception rates, growth rates, meat quantity and quality.

There are many ways of improving your overall herd productivity, but today we talk specifically about one option: cross-breeding. Cross-breeding simply means mating two animals of different breeds, for example, mating a Brahman bull to a Tuli cow. The result is a Brahman-Tuli cross.

Why cross-breeding?

Cross-breeding as a method of increasing the quality of your herd has many advantages over other methods. For a start, cross-breeding results in offspring or calves with hybrid vigour. Hybrid vigour simply means that the offspring from two different breeds has superior characteristics or traits to either of its parent breeds in the local environment. A Brahman-Mashona cross will have the hardiness of the Mashona and the big frame of the Brahman.

Common cross-breeding practices

The common practice is to cross breeds with different characteristics. For example, Mashona cows are known for fertility, hardiness, and diseases resistance in the local environment. On the other hand, Brahman breed has a big meaty frame, but not as hardy as the Mashona in the Zimbabwean context. It iscommon practice to have the Mashona as the mother breed with the Brahman (or another breed) as the sire or bull breed. The genes are roughly 50% each.

Cross breeding in practice

In Zimbabwe, cattle breeding practices can be characterised as uncontrolled mating. This is due to the farming system where a lot of it is communal grazing. For that reason, it is difficult to control breeding.

Controlled breeding: use of paddocks

If you have paddocks, you can control which bulls mate your animals, and at what time. For example, you can have a December-February bulling season, and control when the animals calve down.

Castration

Make it a point to castrate male animals that you do not want to breed. There is no point in keeping inferior bulls in your herd.

Use of Artificial Insemination (A.I.)

Cross-breeding can be facilitated by using artificial insemination. This simply means inseminating semen of bulls into cows by means of an artificial process, when the bull is not there. This process can be made more efficient through heat synchronisation by injecting a hormone analogue (drug). This causes the cows to ovulate at roughly the same times and makes it easy for logistics like handling, labour etc. Please note that signs of heat must still be observed, particularly standing heat when the animal stands to be mated. This indicates the best time to inseminate for maximum conception.

Artificial insemination has several potential merits. First, it can be significantly cheaper than buying high grade pedigree bulls. Bulls are expensive to maintain. Bulls can die from diseases. So by using A.I., you get the genes without the cost of the bull! But of course you have to import the semen, and pay for the A.I. service person.

How practical is A.I. in Zimbabwe situation?

A.I. has been traditionally commonly used in dairy because of ease of handling. If you have an extensive beef operation of several hundred cows, handling and logistics can be a real problem, taking into account that beef animals are not used to handling. That said, A.I. can be something that small players could try, after doing some careful cost-benefit analysis. It is an innovation whose costs and benefits are not clear-cut, and farmers may need to consider their individual circumstances.

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