Using estimated breeding values in your herd

16 Aug, 2015 - 00:08 0 Views

The Sunday News

ONE important animal husbandry management practice is selection. While selection is an active process that requires time and the presence of mind from farmers it is often taken lightly and as a side issue by most smallholder farmers.

Farmers need to know what to look for when making considerations about their breeding stock.

When selecting your breeding stock you should consider an animal’s breeding value which is its genetic merit, half of which will be passed on to its progeny.

Bulls are the easiest and quickest transmitters of genetic merit into a farmer’s herd and hence the reason why serious farmers invest time and resources when buying a breeding bull.

The animal’s breeding value which is a measure of its genetic merit and how much of which is transmitted to the offspring is estimated through calculations and developed farming communities keep records of the estimated breeding values for each breed of cattle and these are used as benchmarks. These are called estimated breeding values (EBVs). This article will not venture into the intricacies of EBV calculations but will look at the key traits that are tracked by the EBVs as these are the subject of importance to the farmer.

The reproductive traits that a farmer should look at when selecting a breeding bull include calving ease, birth weights, days to calving and scrotal size. It is also important to note that you will need records from the breeder or to make reference to your own records if you are selecting from within the stock.

Therefore, record keeping is an integral part of breeding and selection. Calving ease looks at the way in which a cow gives birth and this is considered when selecting a bull.

Bulls do not calve down hence it means you have to look at the daughters produced by this bull to see if they do not have calving difficulties.

If you are buying the bull from outside, records will help here.

This is the same for all the traits which cannot be inspected from the bull itself. Another such trait is the birth weight which is important for two reasons to the farmer, firstly calves with high weight predisposes cows especially heifers to a difficulty birth (dystocia) secondly calves with high birth weights easily attain certain production weights such as weaning weights.

Days to calving which is also called a gestation length EBV is important especially in dairy and artificially inseminated animals.

This measures the time taken from conception to calving down, the shorter the better.

The scrotal size as a selection index is used when buying a bull is related to the performance of the bull in-so-far as mating is concerned. It is calculated from the circumference of the scrotum taken between 300 and 700 days of age of the bull.

High scrotal size EBV sires should produce sons able to handle higher mating loads and daughters that are generally more fertile.

Growth traits include weight records at various ages such as at 200 days, 400days and 600days. The weights at these ages infers on the general growth rate of that animal. The higher the weights than the recorded averages the better.

Another important growth trait is the mature cow weight which is an estimation of the weight which will be attained by the cow at its mature age. Steer breeders wishing to grow animals out to a larger weight may also use the Mature Cow Weight EBV.

There are many selection traits which this small space may not be able to discuss all however what is important for farmers to take home is that selection traits depend also on the primary focus of the enterprise itself.

For example a farmer producing feeder steers will worry more about such traits as carcass weights and intra muscular fat as these are very pertinent in that industry. It is also important to note that there is no wishing away record keeping if you really want to have an effective selection process in your herd.

You may also want to consult seasoned breeders close to you if there are any for tips and tit bits on selection so that you build the herd you desire.

 

 

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