On-Farm Performance Testingfor Meat Goat Doe Herds

Richard Browning, Jr., Ph.D.Associate Research Professor, TSU Institute of Agricultural & Environmental Research MGB-0701.1

Defining On-Farm Performance Testing

Performance testing is the comparativeevaluation of goats for production traits ofeconomic importance: reproduction, growth,and carcass merit. Ancestry (pedigree) andvisual appraisal for conformation (appearance)have been the primary basis of animal selectionin meat goat herds. Most resource inputs (i.e.,herd expenses) go into doe management. Inreturn, does are expected to become pregnant,deliver live newborns, and raise multiple kidswith good growth to weaning. Reproduction isgenerally viewed as the most important trait ofmeat animal production. Reproductive output ina meat goat herd is defined as litter weightweaned per doe exposed to the buck. On-farmperformance testing includes the comparativeevaluation of does for reproductive output, theevaluation of individual kids for weight gain,and in multi-sire breeding programs, herd sirecomparisons for progeny performance.

Objective, accurate recording of doeherd performance allows producers to makebetter selection and culling decisions and tomeasure performance responses to managementchanges. Producers can assess the productionreturn (i.e., litter weight weaned) from theexpenses incurred for doe management.

Conducting an On-Farm Performance Test

Performance records should be easy touse. They can be handwritten records in anotebook or on index cards. Each animal in thebreeding herd should have a separate record.Alternatively, records can be maintainedelectronically on computer spreadsheets or herdmanagement software. Electronic records allow

easy handling of data for analysis or transfer tocentral processing centers such as industryorganizations or universities, particularly forherds with large sets of data accumulated overseveral years. However, a hand calculator and alittle time are all that may be required forprocessing data from smaller herds usinghandwritten records. Under any scenario, properrecord keeping is essential to a successfulperformance testing program.

Animal identification. A prerequisite toperformance testing is proper identification ofanimals. Ear tags and tattoos are the mostcommon forms of ID for meat goats. Assigneach herd member a unique and permanent IDnumber. Assign ID numbers to kids at birthwhen collecting early data such as birth weights,litter sizes, and neonatal deaths. Newborn kiddata need to be matched with the correct doe. Inherds with many does kidding together onpasture or range, it can sometimes be achallenge to tell which kids belong to whichdoes. Rejected kids, early newborn deaths, andthe occasional swapping of kids by does make itimportant to properly and adequately ID kidssoon after birth, preferably within 12-24 hours.

Scales. Scales represent anotherrequirement of a performance testing program.Body weight is undeniably important as ameasure of meat animal performance as well asfor some aspects of general herd management.A small hand-held scale is sufficient to recordbirth weights. A larger livestock scale is neededfor weaning weights. Scales may be bought,borrowed, or rented depending on the needs andresources of individual operations. A scaleshould be periodically checked to ensure that itis accurate and precise when weighing animals.

Contemporary Groups. A contemporarygroup is a set of meat goat kids born and raisedtogether under uniform conditions. Performancetesting for genetic evaluation requires factorslike age, nutrition, and location to be equal forall kids. Kids in a contemporary group are bornwithin a 60-day period and managed togetherfrom birth to weaning. Dams should also bemanaged similarly to weaning. Data from kidsborn outside the 60-day window or manageddifferently (e.g., on show circuit, bottle babies,kept in separate pastures) are excluded from thegroup. Contemporary groups for kids weaned atthree months old are planned 8-10 monthsearlier at the start of breeding. Breeding seasonsno longer than 6-7 weeks assure that kids willbe within the 60-day age range at weaning.

Performance Recording

Body Weight. Primary traits to record ina meat goat herd are the number of kids bornand weaned for each doe exposed to bucks, kidbirth and weaning weights, and dam weight atweaning. Birth weight is the starting point todetermine preweaning growth rate. Recordingbirth weight also facilitates recording the birthdate, identification of the dam, and tagging the

newborn with a unique ID number. Recordnewborn weights within 24 hours of birth.

Record weaning weights at around 90days of age. Weaning weights are usuallyrecorded on one calendar date for a group ofkids that vary in ages. The ages within acontemporary group of kids at weaning shoulddeviate from 90 days by no more than 28 days. It is also useful to weigh the dams when the kidsare weaned. Dam weights are used to calculatethe efficiency of doe production.

Litter Size. For each doe exposed to thebuck, record the number of live births and thenumber of kids weaned. Note stillborns in adoe’s file, but do use them for litter size andthey need not be weighed. Artificially-raisedkids are not credited to the dam for weaninglitter size or weight. In cases when a doe adoptsa kid from another doe, the adopted kid can becredited to the ‘foster’ dam for weaning data.Failure to birth or wean a kid following buckexposure are recorded as zero (0) for the doe.

Animal Evaluations

Kid Evaluation. Because ages vary in acontemporary group of kids at weaning, weightcomparisons can be biased. A 79-day-old kidcannot be expected to weigh as much as a 112-day-old kid. Therefore, weaning weights areconverted to a standard 90-day age basis. Twoequations are used to generate 90-day weights.First calculate average daily gain (ADG):

ADG = (wwt - birth wt) / weaning age After the average daily gain is determined, thesecond equation gives the 90-day weight:

90 Day Weight = (ADG x 90) + birth wt

When birth weight is not available, ADG cannotbe determined. In the absence of birth weightrecords, the previous equations can be replacedwith the following equation based on weight perday of age:

90 Day Wt = (wwt / weaning age) x 90

Adjustments are made to 90-day weightsbecause litter size and age of dam can affectweaning weight. On average, weaning weightsdecrease as litter size increases and young doeswean lighter kids than mature does. Multiply90-day weights by the appropriate correctionvalues (Table 1) to get adjusted 90-day weights.Buck kids are typically heavier than doe kids,but sex of kid adjustments are not requiredbecause comparisons are made within single sexgroups. Buck kids are compared only to otherbuck kids and doe kids compared to other doekids.

Table 1. Correction values for 90-daymeat goat kid weaning weights

Effect Group Value

Litter Size 1 & 1 1.00 born & weaned 1 & 2 1.14

2 & 1 1.042 & 2 1.183 & 1 1.083 & 2 1.233 & 3 1.27

Age of Dam 1 1.10 years 2 1.09

3+ 1.00

Sex of Kid Buck 1.00Doe 1.11

Wether 1.08Values courtesy of David R. Notter, Ph.D., Virginia Tech

An additional step is generating weaningweight ratios. Within each sex group, individualkid weights are compared to the group averageto produce ratios for relative evaluations. Ratiosshow the deviations of kid weaning weightsfrom the contemporary group average. A ratio iscalculated with the following equation:

WWT Ratio = (90 day kid wt /90 day herd wt average) x 100

A ratio of 100 is equal to the group average. Akid with a weight ratio of 122 is 22% heavierthan the group average. Conversely, a kid with aratio of 91 is 9% lighter than the group average.

Sire Evaluation. In herds using multiplesires, kid weights and ratios can be used tocompare sires for progeny performance if eachkid’s sire is known. Buck and doe kid ratiosmay be combined for sire evaluations. Adjustingdoe kids to a buck kid weight equivalent (Table1) is required to combine buck and doe kidweight records for sire evaluation.

Doe Evaluation. For each dam, add theweights of all kids she weaned. Actual or 90-day weights can be used for doe evaluations.Actual weights are preferred because they creditthe ability of does to breed early and raise kidsfor a longer period of time, weaning off moreweight on average compared to does bred laterin the season. When comparing young andmature does, correct kid weights for age of dam(Table 1). A sex of kid correction can also bemade to put doe kids on a buck kid weightequivalent for unbiased litter weight evaluation.Litter size corrections are not made to kidweights for doe evaluation. Zero (0) is recordedfor litter weight weaned of does not weaning akid.

Litter size at birth and weaning shouldbe assessed for each doe. After two or threeproduction years, a certain average number ofkids weaned by does should be expected such as1.5 kids weaned per buck exposure.

Doe production efficiency can bemeasured by how much total litter weight a damis able to wean relative to her own body weight.A heavier doe (e.g., 150 pounds) tends torequire more management inputs than a lighterdoe (e.g., 100 pounds). However, the heavierdoe may or may not be able to convert thegreater inputs into a correspondingly heavierlitter weaning weight. The following equationprovides the efficiency of doe production:

Doe Production Efficiency = (litter wwt/ dam wt at weaning) x 100

Nutritional resources are used by doesfor self-maintenance, reproduction to producekids, and milk production to raise kids. In youngdoes, growth must also be supported. Forageand feed inputs may be available in limited orunlimited supply to does and usually representthe primary expense of herd management. Doeproduction efficiency values vary widely,ranging from less than 50% to over 100%. Doeswith consistently higher production efficiencyvalues within a given set of environmental/management conditions are considered betterconverters of management resource inputs tomarketable litter weight weaned; these does aremore efficient, profitable herd members.

Recording Other Important Traits

Other production-related traits may be ofinterest to meat goat producers. Growth ratesafter weaning can be evaluated on-farm whengoats are retained to heavier post-weaningmarket weights or when developing replacementbreeding stock. Keep detailed health records oneach animal in the herd. A periodic evaluationof records is recommended for traits associatedwith internal parasitism, lameness, abortions,mortalities and other health concerns to help inmaking selection and culling decisions andreviewing various herd management procedures.Although the primary focus has been onperformance testing for preweaning kid growthand doe reproductive output, animal evaluationfor other economically important performancetraits is encouraged in meat goat herds.

Summary

On-farm performance testing of the doeherd is important in crossbred, commercial meatgoat operations expecting good doe-kidperformance with minimal management inputs.On-farm performance testing is important inpurebred, seedstock operations that expect toprovide genetics to commercial meat goatproducers. Each producer will set specificperformance levels for animal selection andculling decisions. Performance records, whenused with visual appraisal and pedigree,facilitate genetic improvement for economicallyimportant traits. Performance records allow forthe evaluation of management procedures andhow changes in herd management affect animalperformance. Performance records, whencoupled with financial records, provide the basisof assessing the economic status of an operationand the likelihood of making a profit orincurring a loss from year to year. Performanceand financial targets should provide direction tobreeding programs. On-farm performancetesting helps to achieve herd goals.

For more information:Richard Browning, Jr.TSU-IAgER3500 John A. Merritt Blvd.Nashville, TN 37209-1561(615) 963-5837rbrowning@tnstate.eduhttp://faculty.tnstate.edu/rbrowning/

This bulletin was developed with USDA-CSREES funds provided toTSU through an NRI Small Farms grant and the Evans-Allen program.

TSU Publication Statement

Tennessee State University: A Tennessee Board of Regents Institution.TSU is an equal opportunity, affirmative action institution committed toeducating a non-racially-identifiable student body. In accordance with theAmericans with Disability Act, persons who need assistance with thismaterial may contact the TSU Institute of Agricultural and EnvironmentalResearch at 615-963-5761.

Publication number: TSU-07-0039(A)-6a-532199