Group Breedplan analyses the growth and production attributes of beef cattle. The analysis includes the growth and production of the individual plus the growth and production of all recorded relatives.
Breedplan includes information on more and more traits and may appear to have become complicated. In reality it is logical and straightforward and provides the only solution to the otherwise impossible task of weighing up individual bull performance and adjusting for pedigree and the performance of brothers and sisters.
Breedplan gives the correct weighting to all available information and then gives a value and accuracy level for each trait measured. The higher the accuracy percentage, the more confidence you can have in the figure. The figures are expressed as EBV's (Estimated Breeding Values). Without any figures selection becomes guess work.
As there are many bulls used internationally (with some bulls used extensively in other parts of the world before they are used in Australia) Breedplan now includes performance information gathered in other countries as a means of improving the accuracy of Australasian EBV's. As more information and data come on stream from production under Australasian conditions, less emphasis is placed on the information generated abroad.
The following is a brief explanation of the figures and what to look for:
Remember, all the figures are calculated from the animal's individual performance
AND the performance of its relatives that have also been measured or weighed.
This is important as it improves the accuracy of the predicted performance of the bull you purchase. For example, if the bull you purchased was light for birthweight, yet one of its parents was heavy at birth, there is a fair chance that some of your bull's calves will inherit the grandparent’s high birthweight. Breedplan works out the likelihood of this occurring and includes it in the estimated figure. The same applies to all other measured traits.
The following explains each trait and how you should interpret and use the EBV for that trait.
Gestation Length (GL)
Some cattle have shorter pregnancies than normal and some longer pregnancies. As growth starts from conception, generally a bull with short gestation length EBV will sire smaller calves at birth than one with a longer gestation length EBV. It also means that the cow has more time to recover from calving to get back in calf for next year. A negative figure here is good.
Birthweight really applies mostly to those looking for a heifer bull. Generally at Hazeldean we get a little nervy when we go much above +3.5 for our own heifer joining, although some areas seem to be able to tolerate more birthweight than we can on the Monaro. Even if you are not looking for a heifer bull, keep in mind that a bull with a big birthweight will sire heifer calves and you may run into problems when his daughters calve down.In a well designed program, birthweight EBV should be able to gradually increase as the size of your heifers at 2 years of age increases through selection for improved growth rate.
A low figure here is good, especially over heifers, but be careful that it does not get so low that calf mortality starts to increase. Also, you should challenge your heifers to be able to handle higher birthweights, otherwise calving ease will go the wrong way.
200, 400 & 600 Day Growth
These figures indicate the sort of weight differences you can expect from the progeny of these bulls (as an average) at 200, 400 and 600 days of age. In other words, if you have two bulls and for 600 Day weight one is +70 and the other is +80, you could expect the bull who is +80 to sire calves that would average 5kgs more bodyweight (as the sire provides half the genes to the calf, 10kg divided by 2) at 600 days than the bull who is +70. A plus figure in all areas is good, relative to your production, provided birthweight does not get out of control.
Milk is the figure that most people find hardest to understand. How can you work out how much milk an animal is capable of producing in its offspring with out actually milking them and measuring the quantity? Milk is obviously an important consideration especially for those beef producers turning calves straight off their mothers. Too much of a good thing can lead to udder problems and also result in failure to get back in calf early, especially if a really good milker hits a tight Spring. There are some cows that will milk well and yet still retain enough body condition to start cycling soon after calving. They are obviously very desirable. A plus figure here is good but beware of the problems associated with extreme production.
Scrotal Size (SS)
There is a strong correlation between scrotal size and both male and female fertility. Bulls with big testicles generally sire more fertile daughters. You may notice a discrepancy between scrotal size on sale day and the EBV. This is because testicles, like just about everything else, grow at different rates in different bulls and rankings will therefore change. As with all Breedplan analysis, information on relatives also has an effect.
The measurement for the EBV was taken at the same time as we started to program the heifers for their AI program back in early September. The reason we did this was to identify those bulls who failed to reach sexual maturity at the minimum age we want our heifers to be cycling. We cull all bulls who fail to reach a minimum of 30cm at 12 months of age as these animals, if allowed to go through into the sale group, will be more likely to breed heifers who will not get in calf early. A plus figure here is good.
Eye Muscle Area (EMA)
This trait is measured by ultrasound when the bulls are approximately 15‑18 months old. As muscling is consistent throughout the body, EMA is a good indicator of overall muscle content when the measurement is taken and analysed in the light of total body weight. It is actually impossible to have an animal with more meat in his hindquarter than in his forequarter, or vice versa. Many years ago, Professor Rex Butterfield dissected numerous carcases from many breeds to prove that as a proportion of total muscle weight, almost exactly the same amounts of muscle were found in various parts of the animal regardless of breed or physical appearance.
Despite general opinion to the contrary, it has been recently proven that increased muscle is not linked to poor fertility or calving difficulty. A plus figure here is good.
Also calculated from ultrasound measurement, high fat depth EBV's will mean bulls that leave fatter carcases and lower lean meat yield.
However, recent research has shown that bulls that are positive for fat generally sire more fertile daughters than those that are negative, all other things being equal. Care has to be taken, therefore, not to select poorer types that lack doing ability and constitution resulting in low fertility. This EBV needs to be kept in balance and extremes of plus or minus should be avoided.
Retail Beef Yield (RBY%)
This figure is calculated to give you the expected amount of retail beef as a percentage of the total carcase weight in a 300 kg carcase sired by this bull. Again you need to understand that as animals receive half their genes from their mother and half from their father, this figure needs to be divided by two to ascertain just how much is a result of the bull's influence.
Intramuscular Fat‑Marbling (IMF%)
As abattoir data is always slow, there are big benefits in measuring live cattle. The Animal Genetics and Breeding Unit (AGBU) at Armidale with Meat Research Corporation, CRC and Breed Society support has been researching marbling scanning since 1996 and has come up with some very encouraging results for genetic evaluation.
IMF% and actual marble score are reasonably well correlated and therefore selection on IMF% will improve marbling. To further improve accuracy, the figure or IMF% calculated by Breedplan also includes abattoir data and overseas EPD data, as well as ultrasound.
The US data on marbling is generated purely from abattoir carcase information. A plus figure here is good.
Days to Calving (DC)
This figure only appears on sires and is an indication of the time taken for his daughters to get back in calf after calving. Some cows take longer to return to their normal heat cycle after calving than others. Those that recover quickly and need fewer days before they get back in calf are obviously more worthwhile having around. A minus figure here is good.
Carcase weight (CWT)
Carcase weight refers to the difference you can expect in the weight of this bull's steer progeny when slaughtered at 650 days of age. Remember that this is an EBV and therefore the actual contribution of this trait to the bull's offspring is half of the number published. This is because only half of any animal's genes come from the sire. The other half comes from the mother.
Calving Ease (CE)
Also appearing on sires only and is self explanatory to a large extent. CE (DIR) is Calving Ease direct and refers to the amount of calving difficulty you can expect from this bull directly from the cows he is joined to. CE (DTRS) is Calving Ease daughters and refers to the amount of calving difficulty you can expect from his daughters. A plus figure in both instances is good.
To deal with the increased number of traits analysed through Breedplan, it is now possible to combine all traits into one figure reflecting your own particular goals and production system. Called BreedObject it is an amalgam of all measured traits into one figure based on commercial value. It is a customised system specifically tailored to your operation and established by placing more emphasis on the traits that are important and less on the ones that are not so important to your particular situation.
If you would like to really pinpoint the right bull for your program, then BreedObject will help you find him.
Contact Wayne Upton, Animal Genetics and Breeding Unit, Armidale.
Tel: (02) 6773 3141 Fax: (02) 6773 3266
$Index values were developed to make it easier to determine which animals are more suited to particular markets. Breedobject creates these indices, where it places relative emphasis on particular traits suited to each particular market.
4 $indexes have been calculated for 4 different markets:
Long Fed / CAAB Index - Estimates the genetic differences between animals in net profitability per cow joined for a high fertility self replacing commercial herd in temperate Australia targeting pasture grown steers with a 270 day feedlot finishing period for the high quality, high marbled Japanese expert market. Emphasis is placed on marbling and 600 day growth.
Heavy Grass Fed Steer Index – Estimates the genetic differences between animals in net profitability per cow joined for self replacing commercial herds in temperate Australia that sells heavy grass fed steers for markets like the EU and light grass fed Jap Ox. Steers. Emphasis is placed on growth and carcase yield while maintaining fertility and marbling.
Short Fed Domestic Index - Estimates the genetic differences between animals in net profitability per cow joined, for an example high fertility self replacing commercial herds selling feeder steers and heifers for the short fed domestic feedlot trade. Emphasis is placed on growth to 400 days and high carcase yield while maintaining fertility and marbling.
Terminal Index - Estimates the genetic differences between animals in net profitability for a commercial crossbred herd where no animals are kept for breeding. Emphasis is on growth and carcase yield with no weighting placed on calving ease, female fertility or milk.
Interpreting $index Values
There are now so many EBV's to take into account, it is difficult to decide what relative emphasis should be applied to each trait when selecting a sire. For example, if you are targeting the Japanese market how much emphasis should you place on growth EBV's compared to IMF%?
The software program BREEDOBJECT creates a selection index which combines individual EBV's into a single overall value to help overcome this problem.
The program calculates in units of relative earning capacity ($) which ranks animals on the balance of their Group Breedplan EBV's to suit particular
breeding objectives and end market scenarios. $index Values can be used to predict differences in the net profit resulting from the use of one bull over another.
Eg. If we compare a sire with an $index Value of +$80 to another sire with a $index Value of +$50 for the same breeding objective, the first sire has the potential to produce an additional ½ x ($80‑$50) = $15 per cow joined (progeny receive only half the $index Value differences between the sires, as half of their genes come from their dams).
If the sire was joined to a total of 200 cows during his herd life, then we would predict that the superior sire has the potential to generate an additional
(200 x $15) = $3000 more revenue than the inferior sire.
For more information on BreedObject and more detailed explanation of the new $index Values: www.angusaustralia.com.au