The goal of expanding the Conception to Consumer program is to generate more valuable data for the production of accurate EPDs on young animals that may be candidate breeding bulls. That said, it is important that in committing two years time and the money associated with testing a bull you are following the necessary guidelines to ensure the data you generate is valuable. The guidelines as listed below are general and each different situation will require consultation with the office to ensure that the data you generate is as useful as possible.
A contemporary group is a set of cattle of the same sex that were born within a 90-day period and were subsequently raised together under the same conditions until slaughter at the same location and time. Contemporary groups will be used to form the initial basis for comparison of individual progeny. Contemporary grouping is used to ensure that all cattle within the contemporary group have equal opportunity to express their genetic merit thus differences between the cattle are mostly due to genetic merit and not management, treatment or other non-genetic differences.
Reference sires are used to provide genetic links across contemporary groups within and across years. In addition reference sires enable adjustment for non-genetic differences between contemporary groups and adjustment for differences in the genetic merit of the cowherds used to produce the progeny test calves. Reference sires should have good pedigree links to the general Charolais population and have a high accuracy carcass EPD. Because of the critical value of reference sires the CCA will designate reference sires for use in the CtoC program. There must be a minimum of two reference sires per contemporary group to ensure accurate evaluation of test sire(s) within the group and tie the group to the rest of the Charolais carcass database.
There is no general guideline as to the number of progeny per sire. The number of progeny tested will influence the accuracy of the evaluation since the accuracy increases as the number of progeny tested increases. However just increasing the number of progeny tested results in more cost and will influence the number of herds that can participate. The guideline that will be used in the CtoC program will be one of attaining a certain level of accuracy of evaluation not just a certain number of progeny per sire. This is due to the fact that the structure of the test, number of contemporary groups and number of test sires relative to the number of other sires in a contemporary group will influence the accuracy so each situation needs to be examined based on its own situation. The concept of an “effective number of progeny” will be used. The effective progeny number directly influences the accuracy of evaluation and is less than the actual number of progeny tested. The effective progeny number depends on the number of progeny from a specific test sire and the number of progeny from other sires in the same contemporary group. The effective progeny number for a given sire can be directly added across contemporary groups. CCA staff following consultation with the member conducting the progeny test will suggest the number of progeny per test and reference sire.
There will need to be, at a minimum an AI program in place to allow mating of some cows to reference sires. In most cases test sires will be used across herds as well and a larger AI program will be required. Producers should use an estrous synchronization program in order to reduce the amount of labour required for AI mating and to ensure a narrow age range in birth dates of progeny. All cows must be randomly bred to test and reference sires based on breed and age of cow and EPD in the case of purebred cows (i.e. no selective mating). This ensures that each sire has been mated to a comparable set of cows. It is advisable not to use heifers if at all possible.
Improper identification of progeny and carcasses is the most common reason for failure of progeny test programs. It is absolutely imperative that each progeny has its own unique identification, as does its sire and dam. Breed composition and age of the dam must also be recorded for non-registered dams. In addition, different slaughter plants use different identification systems so it is important that contact be made with the slaughter plant to ensure a system of transferring or cross-matching the progeny identification with the carcass identification is available. The national identification number can be used as a source of identification.
Progeny can either go on feed directly after weaning or can be back grounded and go on feed at about 12 months of age following a yearling weight. Contemporary groups must be treated in the same manner regardless of the option chosen. It is preferable that all cattle are grouped for finishing at one location and managed according to industry standards. Calves should be on finishing rations for a minimum of 180 days following weaning and yearling cattle should be on feed for a minimum of 100 days following back-grounding. Slaughter should occur at a compositional endpoint for all cattle. Cattle should be slaughtered in a complete contemporary group when the group averages an industry standard back fat or weight endpoint. If a contemporary group must be slaughtered on different days for grading or plant capacity reasons then each sire must be represented, preferably equally in each slaughter group. In no case can animals be selected for slaughter on an individual basis when they reach a desired endpoint.
