The Group Math Challenge

Canadian Charolais breeders have a fantastic record of collecting and reporting weights and other measurements on their cattle. The CHARM program was a game changer for Charolais when it was introduced many years ago. Each year, breeders invest time and effort to collect thousands of pedigree, birth, weaning and yearling measurements and report them to the CCA. These measures are used in genetic evaluation to rank and compare Charolais genetics in relation to each other so that breeders and their customers can select cattle that fit their specific needs. They have become an important part of both selection and marketing programs for the industry.

It is wonderful to be able to talk about weaning weights or scrotal measurement on a bull, but the rubber hits the road when we say “compared to what?” This is what a contemporary group does.

A contemporary group is constructed from a management group. A management group should include all cattle/calves that are managed in the same way. The system adjusts for various things, such as splitting calves based on their sex, season of birth, prior management, adjusting for age differences, age of the dam, and separating cattle that were weighed on different days. This is all done in the context of a management group. The breeder has to define which cattle were given similar opportunity to perform.

The task of assigning management groups is one of the most important pieces of information a breeder will complete on their herd each year. For example, in your management system, it may not be fair to compare calves born in January/February to those born in March/April. As a breeder you could then assign different management groups to calves born in the two different time frames when you report your calving data. Likewise, calves that are raised in differing environments preweaning, or on a different ration after weaning should be assigned to different groups. The computer system at CCA automatically splits calves based on sex, a 90 day age window and prior management, so breeders to not need to be overly concerned about remembering how cattle were managed in prior time periods. As a breeder your management group information will provide the ultimate division of calves into those raised under like conditions, so at each reporting stage, try to group like-managed cattle together.

A good rule of thumb is that if you rounded the cattle up and brought the cattle into your handling facility (scale) as a group they should probably be in the same management group. Calves that were sick, or didn’t have the same opportunity to perform can be assigned a different group number from the other calves.

The biggest failure in recognizing “superior genetics” occurs because of not reporting “inferior genetics”.

Often the temptation is to not report the less desirable end of the cattle, particularly if there is a cost associated with doing so. Failing to report information can dramatically affect how cattle compare with each other, which is the basis of the EPD system. Let’s look at a very simple example of a calving group with 3 bull calves.

If the breeder collects the weights and then doesn’t report the heavier calf to the CCA because they castrated him at birth, it hurts the deviation of the lighter birth weight calves. In this example the breeder has essentially added 10 pounds to the birth weight deviation of the lightest calf. In other words, the EPD basically compares this calf to the group average of his peers. By not reporting all the calves, we have increased the birth weight EPD of the calves that were reported.

This concept works in reverse for weaning and yearling, where the temptation is to not report the lightest calves, thus shaving positive pounds off the heavier calves in the group. Again, let’s look at a very simple example of a group with 3 bull calves.

In this case the actual weaning weights are somewhat misleading when we compare directly. Perhaps A is younger than B or is out of a first calf heifer. If the breeder collects the weights and then doesn’t report the lower end calf to the CCA, it drops the deviation of the very best calf from +50 to +25, effectively reducing the calf’s growth EPD.

The EPD calculations can only produce animal comparisons using the available information. While you may be aware of the less desirable calves in your own herd, by failing to report the whole group a lot of information about the genetics of every calf in the group is lost, regardless of their performance level.

The CCA assigns contemporary groups using the criteria on the following page:

Sean McGrath

BWT Deviation Deviation (Incomplete (Complete Reporting) Reporting)

A 85 -5 -15 B 95 +5 -5 C 120 +20

WWT Adj Deviation Deviation WWT(Incomplete (Complete Reporting) Reporting)

A 675 700 +25 +50 B 680 650 -25 0 C 650 600 -50

Herd Calves must be from the same herd of origin (performance herd or associated herds) Sex Calves must be of the same sex at birth Birthdate Calves must be born within a 90 day age window (maximum range of 90 days from the oldest to youngest calf in the group. Management Group Calves must have been assigned the same management group at birth by the breeder

Weaning

Prior Management Calves must have been grouped together at Birth Herd Calves must be weaned in the same herd Sex Calves must be the same sex at weaning Weaning Date Calves must be weaned on the same date. The system does allow for weaning dates to vary by 7 days. Weaning Age Calves must be between 140 and 270 days of age when they are weaned Management Group Calves must be designated as being under the same pre-weaning management by the breeder (same management group)

Yearling

Prior Management Calves must have been grouped together at Birth and Weaning. Herd Calves must be from the same herd Sex Calves must be the same sex at yearling Yearling Date Calves must be measured on the same date Yearling Age Calves must be between 300 and 430 days of age when measured. Calves must also have had at least 80 days of post-weaning management. Management Group Calves must be designated as being under the same post-weaning management by the breeder (same management group)

SAUNDERS CHAROLAIS Thank you for our best bull sale ever…

Special thanks to these purebred breeders for showing confidence in our program: Rollin’ Acres Charolais & Whiskey Hollow Cattle Co.; Ledbetter Charolais, TX (5); Where Eagles Soar Charolais and to Sarah Buchanan and Cattle In Motion for their help with the sale. Please join us April 7th, 2012 for our 7th Annual Sale

RR 3, Markdale, ON N0C 1H0 T 519-986-4165 • saunders@bmts.com Cell: Brent 519-372-6196 • Darrell 519-373-6788 John & Marie • Brent & Marni • Darrell & BillieJo