Section 03 – Beef Cattle Recording

From ICAR Wiki

Beef recording is a basic tool for herd management as well as for genetic evaluation and breeding. Its aim is to collect information about economically relevant traits that show genetic variation and that are used for the calculation of genetic proofs.

Objectives

As shown in the ICAR survey of 2001, many countries have been involved in beef recording for decades and independently developed national approaches of their own. As a consequence, a huge diversity of national recording schemes can now be observed at present. In view of this background the present guideline aim to provide:

  1. A common understanding of beef recording schemes that enables producers and breeders to communicate efficiently across countries.
  2. Global standards in beef recording.
  3. Advice and help for the establishment of new national beef recording schemes.
  4. A solid data interface for genetic evaluation of beef characteristics.
  5. For the improvement in the reliability of genetic proofs, by implementing appropriate data structures.
  6. For the improvement in the accuracy of genetic proofs, by the identification and recording of the important non-genetic effects.
  7. For the establishment of an international data dictionary for beef cattle which allows for efficient national and international data exchange.
  8. Assistance to recording and breeding organizations involved in genetic evaluation programmes.
  9. A reliable code of practice.

Scope

The present guideline aims to provide guidelines for the relevant matters which must be undertaken in the routine execution of beef recording schemes.

Beef production is predominantly based on specialised beef breeds that use natural mating, the rearing of calves by their mothers and the finishing of the young animals in specialized finishing units. On the other hand, dual purpose and dairy breeds that mainly use artificial insemination and separate the young calf from the mother immediately after birth, also contribute significantly to beef production in many countries. Therefore, the present guideline aims to provide for the recording of all cattle used for meat production.

Genetic evaluation is not considered in detail in these guidelines, as this field of activity is subject to highly sophisticated approaches which are continually enhanced by teams of specialists. Standardisation would be inappropriate, as it would impede future developments. The ICAR survey clearly indicated two main beef recording traditions. The European type approaches on the one hand and North American type approaches, as represented by the Beef Improvement Federation (BIF), on the other hand. The differences between them can in the main be traced back to substantial differences in consumer’s demand impacting the pricing system and consequently the selection objectives and also the significant differences in the production environment and in particular herd sizes.

The present guideline aims to combine recording standards of all regions in as much as this is possible. However, overall uniformity can not be fully accomplished. For example no agreement about weight standardisation in weaner calves has been achieved todate. Most European countries use a standard age of 210 days whereas 205 days are applied in North America. Differences such as this should not be viewed as failures in developing international standards. It matters little when weaner calf weights are recorded or to what age they are adjusted, as long as all of the pertinent information is furnished, such as weight, date of recording and contemporary group information. Documenting differences enables the person interpreting data to see that “weaning weight” from different sources may not mean the same thing, but with the appropriate information it may be possible for the values to be adjusted and used to compute a meaningful comparison or evaluation.

The guideline recommends basic procedures. However, there will be situations where national organizations will develop more refined procedures that are more suitable for their members. Furthermore there might be national or legal restrictions in the use of proposed or recommended units of measurements (e.g. non use of metric units) thus preventing a body from using uniform international standards.

General

Applied beef recording schemes

Beef recording requires recording schemes that can accommodate beef production as implemented in practice. The recording procedures must account for all important effects including the existence of genotype by environment interactions. Beef recording may be undertaken in:

  1. Breeding farms.
  2. Finishing farms.
  3. Individual test stations.
  4. Progeny test stations.
  5. Abattoirs.

In accordance with existing ICAR terminology recording methods “A”, “B” and “C” may be used to describe the following methods of recording.

  1. The A method means recording done by a technician.
  2. The B method means recording done by the farmer.
  3. The C method means recording done by a mixed system of recording by farmers and technicians.

Factors to be considered

The following factors should be considered as basic requirements in beef recording:

  1. A contemporary group may comprise of animals of the same breed, sex and age range kept under the same or at least similar management conditions. Its definition should be carefully established.
  2. Tests on animals should be organised in such a way that maximum information can be obtained. This particularly relates to the composition of contemporary groups. This applies especially in relation to the degree of relationship within the contemporary group. The contemporary group animals should be as unrelated as is practically possible.
  3. The animals must be identified permanently by a unique number that is always retained with all individual records or documents relating to the animal.
  4. Invariant or permanent animal data and further basic information on the animal should be stored in a centralised database. All performance data on an animal should be verified and correct on loading to the database.
  5. National cattle databases used to identify, register and monitor birth, movements and the death of animals should be used in the beef recording schemes as far as this is possible.
  6. All personnel charged with data collection duties must understand the need for accurate and dated records, which should also include the identification of the recorder. Data may be collected by farm personnel or trained technicians depending on the trait. Complex traits such as conformation assessment using a linear scale or ultrasound measures of fat and muscle must be collected by trained personnel that undergo routine evaluation and retraining procedures when necessary.
  7. Data verification systems must be in place which undertake thorough record checks and identify and reject inconsistent or unacceptable data.
  8. The contemporary group should include the progeny of at least two sires.

Principles of beef data recording

It is essential that some basic principles should be taken into account in beef recording practices to improve recording efficiency, data storage, data exchange and usability of the animal’s performance data. Throughout the whole recording process, there are four essential key pieces of information which should be included in any animal’s data record:

  1. Identification number of the animal.
  2. Date of recording.
  3. Identification number of the location (farm, station).
  4. Identification number of the recorder (recording person).

It is desirable therefore for practical reasons to allocate standardized unique identification codes or numbers not only to the animal but also to locations (holding ID) and to recording personnel. The animal’s holding identification together with recorder identification provides information which allows for the correction for environmental effects and therefore is needed for statistical analysis and genetic evaluation. Furthermore the information in respect of the recorder (recording technician) allows for identification of recording methods (A = recording by official technicians; B = recording by the keeper; C = mixed systems), in accordance with the general ICAR standards.

In general, details relating to an animal can be categorised into four different types as follows.

Invariable data

There are 3 groups of invariable data:

Invariant animal data

This includes all data that are specific to an animal, are available at the birth of the animal and do not change during its lifetime. This set of data comprises at least:

  1. The ID no.
  2. Birth date.
  3. Birth location.
  4. Birth type (single, twins, triplets etc.).
  5. If the animal is an identical twin or a clone, the ID no(s) of the other genetically identical animal(s).
  6. Sex.
  7. The breed or breed composition.
  8. The ID no. of the animal’s genetic parents.
  9. Information in respect of embryo transfer if applicable.
  10. ID number of recipient dam in case of embryo transfer.
  11. Information in respect of fostering if applicable.
  12. ID no. of foster mother case of fostering
Invariant location data

All holdings should have a permanent unique ID to identify correctly fixed effects in genetic evaluation and to study the evolution of these fixed effects (specially herd effects) over time. Furthermore this fixed location ID allows for tracing the origin and later locations of the animal as it moves through the whole production chain.

Invariant recording personnel data

Many records are influenced by an operator or recorder effect. This applies not only for subjective assessments such as linear scoring but also to some degree to measured traits like weights, as the accuracy of the recording and other individual influences differ significantly between recording persons. Therefore, in the case of data recorded by technicians, the operator’s ID number should be included in each record.

Life history data

This class of animal data includes information on the status of the animal (alive or dead, suckling or weaned etc.) and the farm or management conditions the animal is kept in. These data are time-critical in that, for a given animal and a given date, it should be possible to retrieve all relevant information pertaining to management condition, reproduction status etc. There are two main areas of information that have to be collected and permanently updated in this class of data.

Physical location of the animal

Many animals change location during their lifetime. Records may start in the birth herd, continue in a finishing herd or test station and then be completed in an abattoir. The date of arrival and date of departure from each establishment must be recorded so that data collected during each period can be verified if necessary from the recording herd. The identity of an animal must not change between locations. The original identification must be checked before it leaves one location for the next and then checked again on arrival.

The standard format for recording a change of location or status may include the following:

  1. Animal ID.
  2. Date of change of status/location.
  3. Recording person.
  4. Current location: farm ID (management-group within farm if applicable).
  5. New location: farm ID (management-group within farm if applicable).
  6. Range of codes to describe such events as weighed, weaned, died, sold for breeding, sold for slaughter etc.

Animal movements from one herd to another or between management groups within herd, should be recorded as soon as possible.

Reproductive status of the animal

The reproductive status describes the standing of the animal in respect of its breeding cycle/status. It includes such events as mating, insemination, embryo transfer and birth/calving for females, and castration for males. If females are kept with one or several bulls during the mating period, then all possible mates in the mating time window should be recorded. Where natural service is used, then the dates of introduction and withdrawal of sires should be recorded.

The relevant data can also be collected in a standardized format:

  1. Animal ID.
  2. Date.
  3. Recording person.
  4. Actual location: farm ID (management-group within farm if applicable).
  5. Code to describe the reproductive event.
  6. ID of other animal(s) involved (e.g. mating partner, calf, foster calf etc.; if applicable).

Having these two types of data of an animal’s life history, it should be possible to access all relevant information for the calculation of and statistical analysis of performance data.

Recorded data

Recorded data are those details directly recorded on an animal or animal group. It includes both objective measures and subjective assessments.

A number of general principles apply in respect of this data.

  1. Provided there is no conflict to legal national units of measurement the data should be recorded in metric units (meters or centimetres, kilogram).
  2. All recorded data should be stored as raw data without any adjustment or transformation.
  3. Recorded data should include information about all known non-genetic effects and circumstances affecting the level of recorded performance.

It should be noted that a ‘recorded trait’ should strictly be the actual measurement, count or subjective score. If a trait. has to be standardized for a given age or for environmental factors, the resulting adjusted weight is a calculated or derived trait. Adjusted weight may be a function of the recorded weight and age derived from the weighing date and the birth date. Thus, ‘weight’ is a recorded trait, whereas ‘weight at 200 days’ is a calculated or derived trait. In principle, 4 different types of data records can arise.

Objective measurements

Measurements like weights, heights etc. which are assessed with the use of some technical equipment. These measurements, if recorded properly have a high degree of accuracy and are relatively easy to standardize if the definition is clear. However, it should be mentioned that some recording device (e.g. ultrasound measurements) needs careful training and supervision of the operator as otherwise the accuracy of measurement is not guaranteed.

Date/Time

It is strongly recommended that for recording purposes, the recording date should be used rather than the animal’s age. The reason is, that additional information is required to derive the age of an animal, and this may lead to erroneous recordings, arising from different formats (age in years, months, or days) or just deficient or inaccurate information which can subsequently be corrected. The recording date allows for the calculation of age when combined with the birth date. The birth date should be recorded in the database for every animal.

The date of recording also provides information on the month or season in which the recording has been undertaken in. This information may be useful for the further interpretation or statistical/genetic analyses of the recorded data. Where date of data collection is recorded then the date should be stored as an 8-digit number using the format 

 YYYYMMDD.

For most performance traits the date of data collection is sufficient information, the time not normally being necessary unless needed for management reasons. However, where recording time is collected then the 24-hour clock should be used. The time should be stored as an 6-digit number using the format 

 hhmmss.
Nominal classification

This occurs where observations are recorded in discrete, unordered classes, like breed or reason for disposal. Well defined and comprehensive categories are required to gain as much information as possible. The classes should be mutually exclusive, i.e. no overlapping of classes should occur. There may be a need for an additional open class for all cases, that cannot be attributed to one of the defined classes. This class should be as small as possible and should include a brief description in order to facilitate the creation of additional classes if necessary.

Subjective scores

This type of recording classifies animals, using a finite ordinal scale, into one of a number of possible classes. Often the classes are an ordered sequence of numeric scores, where the lowest and the highest numbers represent extreme phenotypes expressed in the population under consideration.

It is desirable that descriptions of the different classes be provided in text and where appropriate as pictures/drawings. As outlined later, the main problem with subjective scores is to ensure that values are comparable, even if they are assessed by different persons or by the same person at different points of time and at different locations. This requires clear definitions, ongoing and systematic training as well as the permanent supervision of the recording process. It is essential that periodic verification of the aptitude of the recording technicians be undertaken.

Regardless of the type of recorded trait, it is possible to use a standard format:

  1. Animal ID (or group of animals if applicable).
  2. Date of recording.
  3. Recording person.
  4. Actual location: farm ID (management-group within farm if applicable).
  5. Trait name/trait code.
  6. Trait value.
  7. Additional information pertaining to the animal.
  8. Additional information pertaining to the recording procedure.

It is essential, that for all recorded traits in a given recording scheme, the trait be sufficiently well defined. Additionally unique two or three letter trait codes may be specified (e.g. one code for “shoulder width”, another code for “roundness of thighs” etc.) where it is not practical to use the full name. It is strongly recommended to use trait definitions and/or trait codes in accordance with international standards where available from an international breed umbrella organisation.

Calculated traits

This type of trait is different from the other categories, as calculated traits are derived from the ‘raw’ data information. These traits are calculated according to clearly defined rules. Where the calculated trait requires complex computing procedures or is frequently used, the results may be stored rather than re-calculated each time.

In general, calculated traits may be divided into three different classes of traits.

Counts

This category include summarized information from recordings such as the number of inseminations or matings per mating period, the number of calves born and the number of ticks observed per unit area.

Adjusted or derived traits

Raw data will often have to be adjusted to a defined age, weight, or length of testing period, to comply with the defined standard. If, for example, the weight at 365 days is defined as a standard beef trait, but an animal which is born on March 1, 2000 is weighed on March 15, 2001, the recorded weight is taken at 380 days. Therefore, it has to be adjusted to the standard age by using a linear or other adjustment procedure.

For these classes of traits it makes sense to use a similar data format as for the unadjusted recorded trait. Distinct trait codes should be used in order to avoid confusion. Information that already has been accounted for in any adjusting procedure is omitted.

Functions of several recorded traits

A number of interesting performance traits are derived from a combination of recorded traits. Daily gain in the test period for example is the difference between weight at end and weight at start of the test period, divided by the difference of age at end and age at start of test period, expressed as grams per day. This type of data can be derived both from raw recorded data and from adjusted traits. With these kind of traits, one often has several overlapping additional pieces of information. For example combined traits are recorded by different recorders, at different dates, and at different locations. Combined traits therefore should be defined to be largely independent of this type of additional information. A daily gain in a test period should pertain to a standardized test length. The trait definitions given in the following section will specify which additional information is needed in detail. The resulting general data format for calculated traits may be as follows:

  1. Animal ID (or group of animals if applicable).
  2. Date of recording (start/end of test period etc.).
  3. Age of animal.
  4. Relevant location.
  5. Trait code of calculated trait – where applicable.
  6. Value of calculated trait.
  7. Additional information pertaining to the animal (e.g. contemporary group).

Note that in this case the age (as a calculated trait) is included, while for recording purposes, it is strongly recommended to record actual dates of events.

Genetic proofs and other population-related indices

This type of data applies, if an animal’s performance is related to the performance of other animals in the same population. Genetic evaluation includes trait information (raw or adjusted), pedigree information, classification of fixed environmental effects and covariables etc. Typically such analyses are done for all animals of a population simultaneously.

Results of genetic proofs are by definition independent of any environmental factors, but values may change over time. Therefore they should be stored with the animal’s identification number, the date of estimation together with a definition of the reference base used in the particular genetic evaluation.

Data requirements for the calculation of genetic proofs

In most cases the required data formats for trait information, fixed and random effects and pedigree information are clearly defined in the genetic evaluation system. The data file should be provided in a standard format. Where raw data is subjected to ongoing maintenance which allows for changes of historical data (e.g. change of parentage, fixed effects etc.), submitted data for genetic evaluation should include all animals of the relevant population rather than just a subset of new or recently recorded animals. Data for the calculation of genetic proofs should comprehensively account for management conditions and other non-genetic effects affecting the animal’s performance. Much attention should be paid in the definition of contemporary groups held under similar management conditions. However, the definition of contemporary groups frequently will be a compromise between a precise specification of the group with possibly loss of contemporaries on the one hand and a wider specification with loss of information accounting for fixed effects. Usually the pedigree file is a separate file containing the animal identification number and that of its parents together with breed sex and birth date. The pedigree file should contain all animals contributing to the genetic structure of the breeding population. Where pedigree data originates from separate regional or historical sub-populations or separate databases, it may happen that different ID numbers and/or different names of identical animals occur. Therefore special consideration should be given to identifying and attaching unique ID numbers to the relevant animals.

There are some special situations which need to be taken into account:

  1. In case of identical twinning and cloning, it is necessary to record the fact that two or more individuals are genetically identical, since on the basis of pedigree information alone (identical parent IDs), these animals would be falsely identified as full sibs.
  2. In genetic evaluation systems it is common practice to include ‘genetic groups’ for founder animals. Animals with unknown parents are grouped according to age (year born), country of origin and/or breed composition (if more than one breed is included). Therefore, it is essential to record this data especially for older animals in the pedigree file.

Data storage and management

Given that genetic proofs will be used for the assessment of the production or breeding potential of an animal, it is essential that data are stored in a centralized form, which typically would be a national database, but also may be a database at the level of regions, large farms, commercial breeding companies or breed associations etc. The necessity for a database results from the fact, that performance data of different animals or the same animal at different ages might be combined to retrieve the relevant information. Ideally, data from one ‘breeding population’ are stored in one database or in databases following a common structure with well established links and defined interfaces for data exchange. The data structure should be defined in such a way, that flexible and efficient use of the relevant data for a variety of purposes is enabled. ‘Structure’ means both the hierarchy of different types of data and the general format, in which data should be recorded and stored.

Specific recommendations for data collection

Beef Cattle Identification

Animals

Animal identification is outlined in detail in section 1.1. of ICAR’s International Agreement on Recording Practices[1]. The following chapter therefore only provides a brief overview on the most important aspects for identification issues. More details can be found in the relevant International Agreement.

Having decided on which performance traits are to be measured, it is then vital that a system is adopted that successfully records data relating to an individual animal and allows it to be transferred to the body responsible for genetic evaluation. The key to this success is an individual animal identification number.

The recorded animal identity must be unique to that animal. The approach taken in the EC is to have a two-character code for the country and then a numeric code for the individual that may incorporate geographic and herd information in addition to the animal number. Within Breeds Associations, a numbering system may be used allied to ear tags or tattoos. This may be in addition to the official governmental numbering system or it may be a stand alone system. Where both systems are in use then one numbering system must be agreed as the definitive identifier and used in all data collection, communications and evaluations concerning an animal. Where an official governmental identification system is in place, it is recommended that this identification system be the primary identifier for each animal.

The internationally accepted standard for an animal identity number is a maximum of 12 digits (including a check digit where used) together with the alphabetic ISO country code if the country of origin needs to be identified. Each newly born calf must be tagged with its unique identifier as close to birth as possible. Ideally this should be within 24 hours of birth but could be up to 30 days provided some temporary measure is taken to ensure its identity is not confused with cohorts. The animal’s identity number may be attached to it by, a tag, tattoo, sketch, photo, brand or electronic device. The preferred methods of attachments are those least likely to be confused or lost. Dual identification with a combination of methods or duplication of one method (for example two tags – one in each ear) are recommended for insurance.

Compared to the visible animal ID, a 3-digit ISO country code may replace the alpha country code for data storage and data transfer. In accordance with ISO 3166, the resulting number is composed of 15-digits where the first 3 digits represent the country of birth and the remaining 12 digits represent a unique number within the country of origin. Leading zeros are recommended to fill up to 12 digits. Animals that lose their identity must be re-identified, wherever possible using their original number If doubt over the identity exists then all possible efforts should be taken to determine the true identity. The use of DNA genotyping from known (or suspected) relatives should be considered.

For the purposes of performance recording it is essential that the records of calves that are born dead or, die shortly after birth are entered in the system. This can be done without identification of the dead calf if the relevant calving is seen as an event of the appropriate dam.

Cattle that move from one country to another or become parents to offspring in another country (through AI or ET) should continue to be identified using their original identity number (and name if appropriate).

In the case of imported animals, where the number has been changed, the official records should also show the original name and number. The original name and number must be reported on Export Certificates, AI catalogues and show and sale catalogues. The responsible organisation must maintain a data base that links the animal’s identity to its performance records and its parents identities. In the case of embryo transfer the genetic parents and the surrogate dam identities should all be recorded.

Parentage recording

Parentage recording is outlined in detail in section 1.2. of ICAR’s International Agreement on Recording Practices[1]. Again. the following section only aims to provide a brief overview on this subject.

The identity of the animals served and the service sire must be recorded on the farm on the day of service for AI. For groups of cows bred by natural service the expected parents should be noted and confirmed or deleted at pregnancy diagnosis. The record must contain the identity numbers of the sire and dam including names where available, the breed or breed cross and the date of mating where AI is used or the natural mating was witnessed. If the mating was not witnessed a record of the period the dam and sire were kept together should be made. To verify the parentage record the cow served and the service bull must be properly identified and exist in or be entered on to the database. The gestation length, where it can be calculated should be within +/- 6% of the average gestation length for the breed of the service sire. The service bull must be verified by an AI record or evidence that the sire was on the farm on the day of service or, in the case of ET, a declaration by the supervising Veterinary Surgeon should be available in respect of the required information.

It is recommended that all mating details be notified to the database as soon as possible after the mating event. This will provide the basic information needed to evaluate a range of fertility traits and may help to identify fertility problems early. It is recommended that the mating details should be reported at least within sixty days after the mating. This will help to minimise errors in pedigree and provide useful fertility and gestation information.

Visual inspection or DNA analysis of the progeny may be carried out to confirm parentage.

Farms/Herds

The data collected for specific animals must relate to the birth herd, finishing herd, test station or abattoir in which it was collected. One animal may have data from a number of sources contributing to its performance record so the source must be acknowledged. Farms and herds must be uniquely identified by the organisation responsible for the data collection. This identification may use an existing Government or nationally recognised farm identification system or may be generated specifically for the purpose of data collection. Within farms or herds differential management of cohorts must be clearly identified. Differentiation may occur through deliberately different feeding regimes or through use of pastures with different herbage type and hence nutritional value. The herd or farm identification codes may be formulated to include geographical location in a country. This may provide the basis for improving the design of the contemporary groups to be used.

Life history

Life history refers to the full cycle of an animal’s reproductive and productive herd life. There are many more breeding females and young animals destined for beef production than breeding males. Efficient beef production depends upon three component elements, female reproduction, viability and growth of the young and culled female production. In the production system, the breeding male may be regarded as an overhead.

The reproductive life of an animal is determined by age at puberty (or sexual maturity) and stayability. Age at puberty is the time at which the animal acquires the ability to reproduce offspring and stayability refers to the ability of a breeding animal to remain in the breeding herd. The definition of puberty by precise events in both the male and the female (see Annex) allows for the calculation of age at puberty. In cattle this is between 9 and 15 months of age. But age at puberty is of little practical relevance due to the difficulty to accurately determine the date of these events.

The productive life refers to the period of growth of the young and to the period of fattening of slaughter animals and culled cows. Reproductive and productive lifetimes are influenced by a wide range of genetic, environmental, nutritional and management factors.

Synopsis of life history recording events

Table 3.1. Recording requirements
State Recording requirements 1)
Calf Conception Outcome of a breeding, success or failure
Date of the relevant breeding
Birth Date, identification, sex, weight 2)
Pre-weaning period Date of weight, measurements 3)
Weaning Date, weight, measurements
Post Weaning period Date of weight, measurements
Death/Disposal Date, reason
Breeding female Puberty Date
First and Subsequent Breeding (s) Type (AI, natural service, multiple sires)
Rank of AI
Sire identification
Date (AI, mating, mating period)
Measurements, Weight 1)
Calving Date, parity
Calving ease, Measurements 2), Weight
Death/Disposal Date, Reason
Breeding male Puberty Date
Mating/Semen collection Date, Measurements, Weight,
Semen characteristics
Death/Disposal Date, Reason
Slaughter animal Finishing Date (Start/Finish)
Measurements, Weights
Slaughter Date, Carcass, Measurements, Weight; Meat quality measurements

1) The location where each of these events occurs should always be recorded according to the rules given in the section relating to physical location of the animal. Herd identification and slaughter identification are at stake.

2) Weight means live weight or carcass weight.

3) Measurement refers to any body measurement on the live animal or carcass measurement.

Reproduction and Fertility of Males and Females

Fertility is the most important economic trait in beef cattle. The recording and use of reproductive traits are of major importance in beef cattle breeding because they are directly connected with the birth of animals and the cycle in which animals are born. Environmental effects have a significant impact on reproductive performances, for example season of breeding and diseases. Fertility also can be influenced by management, for example, grouping of calvings and the ability of the breeder to detect oestrus and the system of production. Management treatments which increase the growth rate in growing animals or the production levels in high production cows can also greatly influence fertility.

Some reproductive traits are simple attributes of an individual animal (i.e. age at puberty, gametes production) and others are complex traits because they are related to reproductive peculiarities of the female, the male and the embryo or foetus (i.e. conception, production of a developing embryo).

Basically, most male and female reproduction traits are physiological traits recorded on the animal (sperm production in bulls and oestrus or pregnancy in females) and calculated traits from life history records as for instance dates and outcome of breeding. Calculated traits from recorded life history information provide ages at various stages of the reproductive cycle and facilitate the calculation of time intervals between various reproductive stages. This information also facilitates the calculation of conception rates.

Male reproduction

Male reproductive performances can be assessed by traits measured on the male itself (semen production and libido) or by the outcome of breeding recorded in mates (conception rate). Moreover, AI bulls also can be genetically evaluated for any sex-limited fertility traits recorded on their female’s relatives (e.g. age at calving, calving interval).

With AI bulls all that is required is a source of fertile sperm and with natural service bulls, libido and mating ability are most important.

Furthermore, some experiments show that male reproductive traits are genetically related to female reproduction and to body growth. For example, testis size is related to age at puberty and ovulation rate of female’s to body weight in the male.

Semen production

After collection, semen can be examined generally and microscopically and quantity and quality assessed by measuring or by scoring several criteria. These examinations include the volume of ejaculate, the spermatozoa concentration, the proportion of live spermatozoa, the sperm percent forward motility, the proportion of spermatozoa with morphological abnormalities and the semen freezeability. Procedures for semen evaluation have been developed by the Society of Theriogenology (www.therio.org). Semen examination can facilitate the calculation of age at puberty. After semen processing, the number of straws produced in a specified period can assess the bull’s fecundity.

Moreover, it has been established that total sperm cells production, testicular size and scrotal circumference (SC) are highly correlated in young bulls. Therefore, SC can be used as an indicator of the sperm producing capacity of a bull until about 5 years of age. SC varies with the bred, size and age of the bull. Yearling bulls of different breeds have SC of about 30-36 cm.

Recording Scrotal Circumference

  1. Recorded Scrotal Circumference
  2. The Scrotal Circumference (cm) should be taken at the largest diameter of the scrotum with a flexible tape placed around the scrotum after both testicles has been positioned beside each other in the scrotum.
  3. Calculated yearling Scrotal Circumference Adjustment should be done by breed for age or weight. Adjusted 365 days SC = actual SC + (365 – days of age) x breed adjustment factor.

Sexual behaviour

The male reproductive behaviour is of particular importance in natural service, but the hereditary component of these traits should not be disregarded in AI.

  1. Recorded behaviour traits
  2. Libido or sex drive: defined as the “willingness and eagerness” of a bull to attempt to mount and service of a female. A libido score system has been developed to assess both sex drive and mating ability (Chenoweth, 1981)
  3. Mating ability: the physical ability of bull to complete service
  4. Serving capacity: a measure of the number of services achieved by a bull under stipulated conditions and thus includes aspects of both libido and mating ability (Blockey, 1976, 1981).


Calculated conception rates/breeding index

The conception rate and breeding index are calculated from the outcome of a single breeding, i.e. whether a female conceives (code=1) or not (code=0) or whether a zygote develops into an embryo or not. The outcome of a single breeding can be assessed at different times of the gestation cycle according to the methods of pregnancy diagnosis applied. When recorded on female mates, conception rate may be a practical measure of the fertilizing ability of the sperm cells and as such can be regarded as a fertility trait of the service bull.

To avoid dependencies or complications associated with successive inseminations (variation in cow fertility owing to the rank of oestrus, use of fertile bulls or natural mating for the second and latter mating, varying payment systems related to repeated AI services) only the first inseminations should be used as valid records.

Recorded traits

  1. Breeding index: number of matings / conception, gestation or calving.
  2. It is of practical use only when the same (only one) bull is used to breed each cow and to obtain a conception, gestation or calving.
  3. Conception rate after first breeding: proportion of cows, a bull had been mated to or inseminated with one bulls semen, which conceived or was pregnant at a defined stage of gestation or subsequently calved (calving rate).

Calculated non-return rates (NRR)

Non-return rate (NRR) is a particular expression of conception rate mainly used in AI industry. NRR is based on the observation that a bred/mated cow has not returned for another service within a defined number of days. In order to facilitate the understanding of the NRR and to facilitate the harmonization of calculations between countries, ICAR recommended a precise description for the expression of NRR. The real value of the non-return rates is to the artificial insemination industry since they can be calculated on a large number of inseminations.

In AI, non-return rates are usually calculated as an index of the fertility of the bulls and the efficiency of the inseminators. These indices are based on the assumption that a cow is pregnant to first insemination if she has not been submitted for a second insemination within a specified interval.

Non-return rate generally overestimate the calving rate due to loss of cows from the herd (sale, death), to embryonic or foetal loss, to failure to detect any subsequent heat and also returns to service that occur later than the specified interval. Furthermore, in some cases up to 10% of pregnant cows may show signs of behavioural oestrus.

Refer to Section 6 of the ICAR Guidelines for the expression on non-return rates for the purposes of AI organisations.

Non-return rate after first insemination (NRR) is the proportion of cows inseminated for the first time during a given period of time (such as a month) that have not been recorded as having returned for another service within a specified number of days, and so are presumed pregnant.

Only first inseminations should be considered. This means that first insemination to breed a heifer or first insemination to breed a cow after the end of each pregnancy should only be used

The interval within which the cows are observed for return after insemination should be specified (e.g. 56 day NRR).

The females with short returns only, can be considered either as non-returned females and are as such considered pregnant (included in the calculation) or alternatively as non-inseminated females (and excluded from the calculation).

As a recommendation, short returns, within 3 days after Ai, should be considered like non-inseminated females and both limits of the considered interval should be indicated (e.g. 3-56 day NRR) and these limits should be inclusive. Any other chosen option should be mentioned.

NNR Trait Details

  1. The NRR related to the date of each AI Each of n cow inseminated for the first time within a specified period is observed for return during the same interval (3-24, 18-24) after the date of each AI.
    • Recommended ICAR NNR expression
    • Specified period’ (n=): ‘start of interval’-‘end of interval’ = day NRR
  2. The 60 to 90-day NRR The cows inseminated for the first time within a specified month are observed for return during a 90 days interval from the first day of the month of insemination. In this case, the cows inseminated the first day of the month of insemination will have 90 days in which to be recorded for a subsequent service, while those inseminated the last day of the month of insemination will have only 60 days??
  3. Additional information to record
    • The specific period in which cows have been inseminated.
    • The number of females inseminated for the first time, (n=).
    • The treatment of cows with short returns, either like non-returned and pregnant (included in the calculation) or like non-inseminated (excluded from the calculation).
    • The return interval this side of which a return is considered short return, the start of interval in the expressions given above.
    • The interval during which the returns for another service have been recorded after the first insemination.
    • Factors which NRR have been corrected for such as parity and season.

Additional information about the male

In order to identify the reproduction and the environmental effects, which have an impact on reproductive performances of both male and female, some additional information related to the male, should be recorded. Some additional information about the mate to which the mating is made may also be pertinent to the reproductive performances of the bull (see additional information about the female).

  1. The mode of fertilisation (artificial insemination with frozen or fresh semen, natural ating).
  2. In case of artificial insemination
    • Semen processing (e.g. dilution) in case of AI.
    • Date of semen collection, collection or ejaculate identification on straws.
    • AI by an inseminator or by Do It Yourself (DIY).
    • Identification of the inseminator.
    • AI day of the week.
    • Time interval from heat detection until AI completed.

Female reproduction

The female reproductive performance refers not only to her capacity to produce developing embryos but also to her capacity to give birth to a live calf and to ensure a proper postnatal maternal environment for normal calf growth. Female reproductive traits include fertility traits calculated from life history dates and from the outcome of lifetime events such as breeding, pregnancy, parturition and weaning. Furthermore, sires breeding values can be predicted from most female reproductive traits recorded on relatives.

It should be recognised that some reproductive traits depend on the farmer’s arbitrary decisions such as breeding dates or culling decisions.

Oestrus / Breeding / Conception / Calving dates

The recording of reproductive life history dates in respect of each cow allows for the calculation of the ages at various reproductive events and time intervals between reproductive stages.

Important events include:

  1. Date of heifer first oestrus (puberty).
  2. Dates of first oestrus postpartum.
  3. Breeding dates:
    • Date of first breeding in heifer or dates of first breeding postpartum in cow. This date is needed to calculate NRR.
    • Date(s) of subsequent or repeated AI.
    • Dates of observed natural mating.
    • Pasture natural mating exposure dates (start and end of breeding season).
  4. Fertilizing breeding date, conception date. If several consecutive breeding or matings occurred, the last breeding date before calving is considered as the conception date. Moreover, the last breeding identifies the putative or assumed sire of the calf. The last breeding date should be compatible with the gestation length.
  5. Calving date as a trait of the female.

Calculated ages at various reproductive events

Many ways of calculating ages and intervals as measures of reproductive performances are reported. In order therefore to provide a comprehensive picture of the trait, the details of the animals involved and of the elements included in the calculation are required.

  1. Age at puberty.
  2. Age at first breeding (in days or months).
  3. Age at first successful breeding (in days or months).
  4. Age at first calving (in days or months).
  5. The first calving of the animal should be checked against normal biological criteria and with reported calving number.
  6. Age at nth calving (in days or months).

Calculated interval between various reproductive events

  1. Calving to first oestrus postpartum interval (days), measures the precocity of postpartum oestrus cycle resumption
  2. Calving to first breeding interval (days)
  3. Calving to conception interval (days open), can be computed for previous breeding cycles (days)
  4. Interval between services, assessment of the current breeding efficiency (days)??
  5. Calving interval, the calving numbers involved should be specified, it can be computed for previous breeding cycles (days). Calving events have to be consistent with calving number.
  6. Average lifetime calving interval. This is the number of days between first and last calving divided by the number of calving (days). The number of the last calving should be specified.
  7. Average days to calving = days from bull in to calving when pasture natural mating exposure is practised during a breeding season
  8. Gestation length. The number of days between known conception date and subsequent calving date. In case of several consecutive breeding the last one is considered to be the conception date.

Pregnancy diagnosis, recording of the result of a breeding in female

The pregnancy diagnosis allows the determination of the outcome of a mating, its success or failure can be recorded as a binary trait (pregnant = yes not pregnant = no).

  1. Methods of pregnancy diagnosis:
    • Observation of failure to return to oestrus in a specified return interval (e.g. between 18 and 24 days after breeding).
    • Palpation of ovaries, persistence of the corpus luteum (day 18-24).
    • Progesterone essay (at day 24).
    • Palpation of amniotic vesicle (from day 30-65).
    • Ultrasonic method to detect the embryo (from about day 20), (see Kastelic et al., 1988)
    • Calf birth.
  2. The date of pregnancy diagnosis

Calculated conception rates or indices

Conception rate calculated from the outcome of a mating (whether a cow conceives or not), can be a measure of her capacity to ovulate and to produce a properly fertilizable ovum and her capacity to complete the implantation of the conceptus. As such, conception rate can be regarded as a fertility trait of the female. Moreover, conception is little if any influenced by the farmer because once he decided to breed a cow, success is always the desired outcome. As a female trait, conception rate can also be used to genetically evaluate sires.

Given hereafter are the basic definition of the main conception rates and indices used, but there are various ways of calculating such conception rates and indices. So it is important to define clearly the animals involved in numerator and denominator, the time or the interval at conception diagnostic from breeding date and the breeding number.

  1. Female breeding index: number of matings / conception or gestation or calving. This measure of female fertility is often influenced by farmer’s decisions, for example elite cows may be bred more times than other ones that are likely to be culled earlier.
  2. Number of calves produced per cow and per year at herd level

The outcome of a single breeding can be assessed at different times of the gestation according to the method of pregnancy diagnosis applied. So conception rate should be calculated at a defined day or interval from the date of breeding and could be calculated at the herd or progeny group level. The breeding ranks and parities also should be recorded.

  1. Conception rate: proportion of cows bred in a herd or in a progeny group, which conceived or was pregnant at a defined stage of gestation (day or interval) or which calved (calving rate).
  2. Non return rate at a given interval (see guidelines from ICAR for calculations NRR in male reproduction section).

Number of calves per gestation, prolificacy

The number of calves per gestation is important in so far as it may affect calving mode, birth weight, weaning weight and growth during pre-weaning period. Moreover, in the case of suckling of both twins by the mother pre-weaning growth and maternal ability assessment also are influenced.

  1. Code for number of calves: (1) single calf, (2) twins, (3) triplets or more.
  2. Additional information: suckling of both twins by the mother or fostering of one calf or artificial rearing of one or both. When prolificacy is a trait of interest, the number of embryos, foetuses or calves could be an indicator of the ovulation rate for one oestrus cycle but dizygotic twins should only be considered. Blood groups or DNA polymorphism can assess the zygotic status. Dizygotic twins are considered full sibs.

Additional information about the female

To define at best the management of reproduction and the environmental effects, which have an impact on reproductive performances of both male and female, some additional information related to the female, should be recorded. Some additional information about the male is also pertinent to the reproductive performances of the cow (see additional information about the male).

  1. Time of service with respect to the onset of oestrus.
  2. Mode of oestrus detection (visual, devices, teaser bulls).
  3. The hormonal treatments of the dam if any (induction of oestrus).
  4. The previous calving mode of the dam.
  5. The postpartum pathology of the dam (metritis, retained placenta).
  6. Fertility problems in the dam (anoestrus, anovulation, ovarian cysts).
  7. Cow disposal for infertility / sterility in case of unsuccessful breeding.
  8. Type of calf rearing (suckling calf or fostering of the calf or artificial rearing), which may affect the moment of the resumption of oestrus cycles postpartum. Suckling delays the onset of postpartum oestrus.
  9. Abortion.

Mothering aptitude (see temperament/behaviour)

The maternal behaviour may affect the viability of the calf and can require fostering.

  1. Production trait, the milk yield the cow produces to allow pre-weaning growth of the calf, usually assessed by the weaning weight.
  2. Behavioural trait of the mother towards her calves, i.e. the way the mother takes care of her calves after birth.

Embryo transfer and ovum pickup

In some breeds, Multiple Ovulation and Egg Transfer (MOET) is used as a breeding technique or/and in selection program. Ovum Pick Up technique (OPU) is an alternative source of cattle embryos that required in vitro maturation of oocytes and their in vitro fecundation and culture to the stage of blastocyst before egg transfer.

In order to fulfil the standard data for an animal and to properly use records, the following information should be recorded:

  1. Identification of the embryo and of its genetic parents.
  2. Date of transfer.
  3. Coding of the calves produced by egg transfer.
  4. Identification of the recipient cow.
  5. Coding of donor and recipient dams to identify cows which did not raise a natural calf.

To specifically analyse the efficiency of the multiple ovulation technique, the traits to be recorded are:

Number of unfertilised oocytes/flushing.Number of degenerate embryos/flushing.Number of transferable embryos/flushing.

Moreover some environmental factors may influence the results and particular information should be recorded in the donor cow including the multiple ovulation treatment used and date, the dates of AI and of flushing and the identification of the technician.

As for the result of the egg transfer, the following information should be recorded:

  1. The date of eggs transfer.
  2. The mode of transfer as fresh or thawed embryos.
  3. The type of oestrus of the recipients as natural or by hormone treatment and
  4. The identification of the technician.

Calving ease or difficulty, calving mode

Difficult calvings lead to increased calf and cow mortality and could impair the health of the calf, the health of the dam, her subsequent fertility and her production performances.

Dystocia can be of maternal or foetal origin.

Maternal factors are:

  1. Anatomical or pathological defects in the pelvic canal (variation in pelvic opening area, pelvis immaturity, and fibrosis of the reproductive tract).
  2. Insufficient preparation for parturition or expulsive contractions.

Foetal factors are:

  1. Oversize (relative, absolute or pathological).
  2. Faulty position.
  3. Dead calf.
  4. Twinning.

For breeding purposes, the most relevant causes of dystocia are oversized calf and narrow pelvic area in relation with dam’s age. The presence of a veterinarian at calving is not necessarily associated with these causes, but may have been requested for any of the other causes of dystocia. So the description of a calving mode class by the veterinary assistance is meaningless in so far as breeding is concerned.

Recommended codes for calving mode or ease

  1. Easy calving without assistance
  2. Easy calving with some assistance
  3. Difficult calving (hard pulling, assistance by 2 or more persons, mechanical assistance)
  4. Caesarean section
  5. Embryotomy

Other additional information to be recorded: calving date, parity and age of the dam, sex of calf, calf presentation at parturition, twinning, breed of dam and ID of dam.

Birth weight

The most common cause of dystocia is foetal oversize and the most interesting cause in connection with the breeding ability of the sire for calving ease is the birth weight.

Pelvic opening

Most calving difficulty or dystocia occurs in first-calf heifers. Research indicates that disproportion between calf size (birth weight) and size of the female pelvic inlet (pelvic area) is a major contributor to calving difficulty. As a result, the yearling pelvic measurements can be used as a culling tool to reduce the potential incidence and severity of calving difficulty among first-calf heifers.

  1. Pelvic measurements:
    • Sacropubic (vertical) diameter (cm).
    • Transilial (horizontal) diameter (cm).
  2. Calculated pelvic area (cm2) Estimated pelvic area is the product of vertical and horizontal measurements
  3. Yearling calculated pelvic area Pelvic measurements should be taken between 320 and 410 days of age and adjusted to 365 days of age to accurately evaluate yearling bulls and heifers. BIF proposed formulas for male and female (see annex calculated traits definition), but the adjustment should be breed specific.

Mortality from birth

The time of death can be recorded as date or/and code. Generally, the codes are connected to live history events (birth, weaning, post-weaning) or to time period from such events which should be specified. The usual times of death are given hereafter.

  1. Date of death
  2. Code for time of death:
    • Stillbirth, still-born: dead-born full term.
    • Death during parturition.
    • Perinatal death generally defined as death within first 48H.
    • Death within a specified time from birth.
    • Death in any specified interval.
    • Death after weaning.

From those records, various mortality or viability rates can be calculated, so the animals involved in numerator and denominator and the time or the interval from lifetime event considered should be clearly defined. These rates also could be calculated at herd or sire levels and separated according to different causes of mortality that should be specified.

  1. Calculated calf mortality rate Dead calves, within a time period or towards a defined event, as a % of cows exposed, pregnancies, calvings or calves born alive
  2. Calculated viability rate Alive calves, within a time period or towards a defined event, as a % of cows exposed, pregnancies, calvings or calves born alive
  3. Weaning rate: proportion of calves weaned for a specified denominator
  4. Causes of mortality:
    • Congenital defects.
    • Dystocic calving.
    • Accident.
    • Disease (respiratory, digestive, infectious, metabolic….).
    • Other.

Disposal from birth

The time of disposal can be recorded as date or/and code. Generally, the codes are connected to live history events or time period from such events that should be specified.

  1. Date of disposal.
  2. Code for time of disposal.
    • Postnatal, preweaning, postweaning, other.
  3. Causes of disposal. There are numerous causes of disposal, which can vary from one production system to another. So, an exhaustive list of causes is difficult to establish. Moreover breeders may decide upon an animal‘s disposal based on more than one reason. On can generally classify these causes into voluntary and involuntary decision of the breeder.
    • Voluntary: sale for fattening, sale for breeding, sale for slaughtering.
    • Involuntary: culling for defects, diseases, infertility, sterility, production deficiency, mothering ability, temperament, other.
  4. Calculated age at disposal, at culling. From those records, various disposal statistics or rates can be calculated, The animals involved in numerator and denominator, the time or the interval from lifetime events should be clearly defined. These rates also could be calculated at herd or sire levels and separated according to different causes of disposal that should be specified.
  5. Calculated rates of disposal, for a specified type of animals at a specified age or event or within specified period.

Longevity trait

General

Longevity is an essential part of any breeding goal, reflecting the ability of an animal to cope successfully with the environmental conditions that arise in the production system. The length of the life of an animal can be calculated from its life history data as any survival trait may be defined as the length of time between two events. Longevity may be measured, from birth or from onset of production to the date of measurement of the specific trait for the last time in an animal’s life.

Life history data which are essential for longevity traits (see elsewhere in these guidelines) are birth date, calving dates and date of disposal. In addition for the calculation of longevity traits the cause of disposal needs to be recorded.

Calculated longevity traits

The trait generally suggested to describe the longevity of an animal is the productive life span (or also sometimes referred to as productive herd life). Length of productive life is the period of time between the start of production and the end of productive life. As detailed in these guidelines, this trait may be calculated if the recommendations for recording life history data are followed. The endpoints for the calculation of the length of productive life need to be defined. Typically the productive life of a cow starts at her first calving and ends with her death. In using this data in a genetic evaluation, however, two problems have to be taken into account.

Firstly, incomplete records have to be considered in calculating the length of productive life where a different endpoint than the death of an animal is available. Examples are longevity data of animals which are still alive or which were sold for commercial use. To exclude incomplete records from the evaluation or consider them as dead would lead to biased results. One way to deal with this problem is to use indirect longevity indicators such as whether a cow is still alive at a certain age (‘Stayability’). This method is however associated with a great loss of information. Therefore, it is suggested, that incomplete data are treated as censored and special statistical tools are designed for coping with such data used in analysis. For the latter case, the correct code for cause of disposal is mandatory.

Secondly, for genetic evaluation the ‘functional longevity’ should be the trait of interest, i.e. longevity corrected for performance. In this context, culling for low productivity is disregarded since performance is used as a different selection criterion. Only culling for health problems or other non-production causes is taken into account. As for dairy cattle, the performance being corrected for may be milk yield assessed by weaning weight or a weight at a fixed age.

In many cases, early predictors of productive herd life is used for breeding value predictions in young animals. These predictors are usually associated with linear type traits, body measurements and production records.

Organisation and execution of testing schemes

Data transfer

Glossary of terms

Literature

Sub-sections

  1. ↑ 1.0 1.1 ICAR – International Agreement of Recording Practice. 2003. Approved by the General Assembly held in Interlaken, Switzerland, on May 30 2002.
Retrieved from "http://wiki.icar.org/index.php?title=Section_03_–_Beef_Cattle_Recording&oldid=3309"