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To identify the genetic differences between individuals within a breed, we must first identify differences between individuals within herds. Thus the use of objective measures within herds is essential to the genetic evaluation process. These guidelines have been drafted to help insure the proper collection of objective measures on the ranch.
Collecting data such as weaning weights and birth weights sound easy enough, and it usually is. However, if proper technique and methods are not used, errors can be made that can result in erroneous information from which to base our selection decisions on. Proper contemporary grouping and times to collect measurements will be discussed in depth below. But it is important that we consider the correct techniques. For example, who should do the measuring? While it may seem that it doesn’t matter who reads the scales, it can result in the information being biased, one person may have a tendency to round numbers up while the other rounds down. For this reason it is important that the same person measure each animal in the contemporary group. Also, measuring scrotal measurements on bulls, one technician may pull the tape tighter than another. For these reasons it is important to use good equipment and to be as consistant as possible in the measuring technique and that all animals receive a fair measurement. This may include little things such as cleaning and rebalancing the scales periodically or being sure the same person measures all of the animals in the group. It is also very important to verify the identification of each animal during processing; this will insure that each animal gets credit for its own performance.
The American-International Charolais Association has adopted the whole herd inventory-reporting concept. At the beginning of each year each participating AICA member of the Performance Plus Registry or the Whole Herd Rewards Program will complete and bring current their herd inventory along with other information on every cow in the herd. This information will not only be useful for improving the accuracy of current EPD but also in developing EPD for additional traits that are economically important to cow-calf producers, such as traits that impact reproduction. Currently, the information required for every cow on the inventory is a calf, reproduction code and/or a disposal code. Basically a calf must be reported for every cow, or a reason why a calf was not reported. Furthermore, if the cow is no longer in the herd, then a disposal code must be included. The herd inventory concept is a simple and straightforward system that promotes the complete reporting of performance information. The responsibility of selecting the animals that remain in the herd as registered seedstock or animals that are marketed and promoted as registered Charolais remains a decision of the breeder.
Birth Weights: Calf birth weight is a useful indicator of calving difficulty. Therefore, selection of breeding animals for smaller birth weight EPD appears to be an effective criterion for improving direct calving ease. Birth weight measurements must be taken as soon after birth as possible, calves should also be weighed and then identified with a permanent identification number (tattoo) at this time. The dam ID, date of birth, calving ease score, and dam’s udder score should also be recorded at this time.
Weaning Weights: Many commercial cow-calf producers sell calves at or near weaning, thus increasing weaning weight has a significant influence on market value of the calf crop. Furthermore, weaning weight is influenced by the maternal ability of the dam; therefore the weaning weight information of the calf will contribute information for the Weaning Weight EPD and the Maternal Milk EPD. [ CLICK HERE FOR AGE OF DAM ADJUSTMENTS ] Weaning weights should be taken when all calves in a contemporary group are between 140 and 270 days of age. If the days of age for a calf fall outside these guidelines an adjusted 205-day weaning weight will not be calculated. Other information that is important at weaning is to designate weaning contemporary groups and management codes, read below for more information about contemporary groups.
Information that is often over-looked is the valuable information on the dam at weaning. Body condition scores and a weight on each cow should be collected at weaning. Not only is this information potentially useful for genetic evaluation, but it can also be used as a herd management tool to identify cows that may need to be in better condition before the next calving season. Cows can be grouped and managed based upon age, body condition scores, and weight.
Yearling Weights: Many producers market cattle at yearling time or retain cattle through the feedlot. Yearling weights also have a high genetic relationship to feedlot efficiency of gain. Yearling weights must be taken at no less than 270 days of age and a minimum of 70 days after weaning weigh date; furthermore, cattle must not be more than 430 days of age. Ideally, yearling weights are taken when all calves in a contemporary group are between 320 and 410 days of age (365 +/- 45 days) to calculate 365-Day Adjusted Yearling Weights. At the same time yearling weights are taken, all other yearling measurements should be completed as well; scrotal circumference, pelvic measurements, hip height, reproductive tract scores and ultrasound measurements. More information on ultrasound measurements follows below.
It is also important to identify calves that were on your weaning report but were culled from the herd before yearling weights were taken with an appropriate calf disposal code.
Mature cow size has economic implications for several traits, including reproduction, growth, carcass, and efficiency of growth. It is difficult to pinpoint an optimum mature cow size, because it can vary not only from region to region, but from producer to producer dependent upon management and available feedstuffs. Cow weights should be taken either during breeding season and/or again when weaning calves and reported to AICA on the Calving, Weaning, Registration Report Form. It is important to weigh all cows of a particular management group on the same day.
Individual Animal ID. Identification of individual animals sounds to be rather simple and straight foreword. And it is, if a few simple rules are followed. The ID number selected should not be repeatable in your herd and the method of marking should be permanent, ear tags are easy but are often lost. Each breeder can devise his own numbering system, but there are some limitations and guidelines that should be followed for best results.
The herd number is a series of numbers and/or letters that identify individual calves. In the AICA registration computer program, the herd number can be up to eight characters. Some producers prefer to use the last two digits of the year of birth as the first two digits of the identification number, for example, the first calf born in 1999 would be assigned the number 9901, and then 9902 and so on. Another popular method is to use International letters that have been designated for each birth year. The international letters are listed below. This option is handy to use in conjunction with numbers. For example, J001 and J002 would indicate the first and second calf born in 1999.
A permanent ID is an identification number that will stay with the animal from birth to death, and will be transferred to a new owner. This is important for identification of animals, because if you rely on a less permanent ID system, such as ear tags, animals can lose tags and other less permanent forms of ID and subsequently their individual identification is lost. The most common and practical method is to tattoo the animal in one or both ears with a permanent identification number shortly after calving.
Reasons cows are culled from the herd vary. Many cows are culled for reasons not related to reproduction. Furthermore, many cows are reproductively sound, but calves are not always reported. For these reasons many cows are unfairly evaluated for their reproductive value. Reporting accurate reproduction and disposal codes will aid the breeder and National Cattle Evaluation in assigning more accurate breeding values for reproductive traits. See the addendum for a complete list of reproductive and disposal codes that have been adopted by AICA.
Measurements for height have become a descriptive supplement to many herd-testing programs. Growth data supplemented by linear measurements for height have added another dimension to evaluating cattle and further describing the skeletal size of animals. It is important to recognize that no one frame size is best for all environments and management systems, and frame size should only be used as a tool to aid in the selection process of cattle. Hip height may be used to maintain cattle within an acceptable frame size while selecting for other economically important traits. The recommended point for linear height measurement is at the midline at a point directly over the hooks. Actual measurements should be reported to AICA and not the adjusted measurements. AICA will apply standard adjustment procedures. Also cattle should be measured at the same time that yearling weights are collected between 270 and 430 days of age.
There are numerous methods by which to score teat size and udder quality. The method we have chosen is one that is simple, but yet when applied will improve the udder quality of the females in your herd by giving you valuable information with which to select replacement females. The udder score is a two-digit code in which the first digit represents the udder's suspension and the second digit denotes the size of the teats. The scores range from 1 to 9, with a score of 11 representing a very pendulous, broken floor for the udder and a very large, balloon shaped teat. On the other end of the range is a score of 99, which represents an udder with a very tight suspension and level udder floor with a very small teat size. The scores can have any combination within the range of 11 to 99. The following illustrations show the different teat sizes and udder suspensions. In the interest of space the illustrations do not show all the possible combinations of teat size and udder suspension. Remember that any two digit combination of the two scores is possible and the suspension is scored first. Example: Suspension = 7, Teat Size = 5, Udder Score = 75.
The recommended time to assign udder scores is when taking birth weights. This is the most important time for the newborn calf to be able to nurse.
Identification of contemporary groups is central to an accurate analysis. It is helpful if producers will identify contemporary groups when submitting data to AICA. A contemporary group is defined as a group of calves managed together of the same sex, given equal opportunity to perform, and weighed on the same day. Calves raised in different contemporary groups should be so noted in the pasture or group column. Contemporary groups are formed for both weaning and yearling age animals; furthermore a yearling contemporary group is always a sub-group of the weaning contemporary group. Twin and embryo transfer (ET) calves are usually considered to be in contemporary groups of one, this is because of problems adjusting the measurement to a standard that is comparable to adjustments for other calves. For more information on reporting information for twin and embryo transfer calves see the section below.
It is also important that actual (not adjusted) measurements be submitted to AICA. Adjustments to a standard age will be computed by AICA and reported back to the producer. This is to insure that standard adjustment procedures are applied to all cattle.
The AICA Breed Improvement Committee and Board of Directors have approved guidelines for the standardized collection of ultrasound data on Charolais cattle. These guidelines should be adhered to when collecting ultrasound data on yearling seedstock. AICA ultrasound guidelines specify the use of ultrasound technicians fulfilling the certification requirements of the Beef Cattle Ultrasound Technician Annual Proficiency Testing and Certification (APTC) Program.
Ultrasound data should be collected on all calves in the yearling contemporary group and cattle should be between 320–430 days of age. All cattle must also have a weaning and yearling weight taken at appropriate times and reported to AICA, furthermore a weight should be taken at the time of ultrasound data collection. Along with the ultrasound information the following information should also be reported to AICA: Ultrasound technician information, AICA Registration Number of assigned AICA assigned performance number, permanent identification number, date of birth, sire and dam registration numbers, and group and management codes. It has been a common practice to collect ultrasound measurements only on bulls as an aid to marketing. However, for the purpose of genetic evaluation, ultrasound data on yearling heifers may contribute as much or more to the evaluation as the data collected on yearling bulls.
When collecting ultrasound data it is very important that proper procedures are followed. It is the responsibility of the breeder to supply a squeeze chute with side panel doors to properly restrain cattle and provide access to the region of scanning. Technicians have several thousand dollars invested in equipment that must be protected and the quality of the images will be improved as well if cattle are properly restrained. Cattle must also be dry and clean in the regions to be scanned and out of direct sunlight to allow for seeing the images on the monitor. It is also necessary in most cases that cattle are clipped in the scanning region with no more than 1/2 inch of hair. By following these guidelines and by working with the technician you can improve the quality of ultrasound data that will be collected. If you have any questions about preparing cattle for scanning you should visit with the technician ahead of time or call the AICA Director of Breed Improvement.
It is the responsibility of each producer to contact technicians to make arrangements to scan their cattle. If you are planning to collect ultrasound measurements on your cattle you may contact the AICA Director of Breed Improvement for ultrasound reporting forms, barnsheet, or a list of qualified technicians.
Embryo transfer calves can now be included in National Cattle Evaluation. There is however additional information required before EPD can be computed. Information about the recipient cow is required; information needed is the breed of recipient cow, year of birth of recipient cow, and a permanent identification number for the recipient cow. Contemporary groups will be formed using the same guidelines as for natural calves with the addition of recipient cow information. Be sure to include this information when registering Embryo Transfer calves.
Performance information for twin calves should be reported to AICA. While at this time weaning and yearling information from twin calves is not used by National Cattle Evaluation for the evaluation of weaning, yearling or milk EPD, the birth information is usable. Birth EPD can be computed for twin calves in many cases.
The American-International Charolais Association has adopted guidelines for structured sire evaluation for carcass merit and made them available to producers of Charolais cattle that desire to structure a designed sire evaluation program for carcass traits. Following these guidelines should insure that proper procedures are followed for data collection. Subsequent reporting of data to AICA can then be included in the Charolais National Cattle Evaluation for evaluation of and reporting of EPD for economically important carcass traits. The Structured Sire Evaluation Guidelines should be used by all parties participating in a designed sire evaluation program as the only method of data collection for entry into the American-International Charolais Association genetic analysis for carcass traits. There are many feedlots that will assist the cattle producer in obtaining valuable carcass information that would be useful for national cattle evaluation. Contact AICA for information about these feedlots and for a copy of the AICA Structured Sire Evaluation Guidelines.
These guidelines are intended to aid the Charolais breeder in collecting and reporting accurate performance data for economically important traits. The use of information is dynamic, as technology advances we are able to accurately measure and evaluate more traits. A correct understanding of how and when to measure these traits is needed so that standard procedures can be applied. If you have any further questions about collecting performance information please contact the American-International Charolais Association.
