Management Topics

Jun 7, 2013

Make plans for contemporary groups early

Seedstock producers submit performance data to their associations to produce genetic predictions, and the basis for these are weight/ measure deviations within a contemporary group. To make these genetic predictions as precise and reliable as possible, it is of paramount importance that contemporary groups be formed properly.

The Beef Improvement Federation defines a contemporary group as “a group of cattle that are of the same breed and sex, are similar in age, and have been raised in the same management group (same location on the same feed and pasture). Contemporary groups should include as many cattle as can be accurately compared.” Today, this definition must be modified for the many breeds running multi-breed genetic evaluations since they accept cattle within a contemporary group with various breeds and breed combinations.

For many seedstock producers, the drought we have been experiencing brings new challenges in maintaining large, equal-opportunity contemporary groups. The drought is forcing some producers to split their herds up and move them to whatever grass is available, and these pastures may vary in quality. By definition, a proper contemporary group of cattle should be on the same plane of nutrition.

To maintain the largest groups possible, producers may consider breaking their pasture groups by sex of calf to maintain contemporary group integrity. Another consideration is putting first calf heifers in their own group to utilize the best grass, and contemporary grouping them separately. Some breed associations already separate 2-year-old heifers from cows anyway, and data exists that suggest they should be separated even if your association does not require it.

Also with the drought, as well as some Extension specialists promoting the practice, early weaning is another reality that must be dealt with. If considering early weaning, it is of utmost importance to check with the association you are dealing with to determine their rules for minimum weaning age for calves to qualify to be used in the genetic analysis.

All associations have some minimum age threshold that calves must be for them to be used to produce expected progeny differences (EPDs); therefore, for calves under this age, their data will not be used. Some associations are quite liberal in taking young calves, especially those associations that have adopted regression formulas for adjusting weaning weights; however, some are very strict in requiring calves to be near normal weaning age to qualify for contemporary groups and their genetic analysis. It is also unethical for a seedstock producer to wean calves at a very early age and then send the association weights that the producer has mathematically projected to a normal weaning age. Therefore, seedstock producers must weigh the realities of their pasture and feed situation with their association’s calf age requirements to decide on an optimum weaning date.

The showring will also really confound the proper formation of contemporary groups, especially when it comes to weaning weights. Once an animal starts receiving preferential treatment in preparation for a show, it must be put into its own contemporary group. This includes cow/calf pairs. It is legitimate, but very unwise, to group show cattle together. The reason this should not be done is one can assume only your very best calves are candidates to be shown, so only comparing them against each other rather than the potential full contemporary group will hurt rather than help the show calves’ EPDs. If you are keen to show calves, it is best to creep feed the whole contemporary group and then split them out after weaning.

The reason it is so important to get large, unbiased weaning contemporary groups is that the weaning EPD is used as a correlated trait for the majority of EP- Ds produced by a genetic analysis. This means maintaining valid weaning weight groups is of paramount importance, and there is relatively less genetic information to lose if cattle are removed from a contemporary group after weaning for show purposes. I would like to reiterate that it is unethical to put a calf receiving preferential treatment into a contemporary group with those that are not.

Once a complete weaning contemporary group is obtained, associations have formulas that account for culling. This means if you only keep best calves to develop as yearlings, the formulas give them credit for being above average when their yearling data is collected.

The take home message is that contemporary group data is the basis for all genetic predictions. It is important for seedstock producers to know the requirements upon which their association forms contemporary groups in terms of age minimum and maximums, etc. These groups must be unbiased and as large as possible. With a drought and short feed, this will take more homework by producers to be sure that data can be used. It is also of the utmost importance to maintain whole herd weaning weight contemporary groups because of the trait’s impact on a whole host of EPDs. — Dr. Bob Hough

[Dr. Bob Hough has served as the executive vice president of the Red Angus Association of American and more recently as executive vice president of the North American Limousin Foundation from 2009 to early 2011. He is now a consultant, freelance writer and semiretired.]