> ## Documentation Index > Fetch the complete documentation index at: https://docs.wheycoolranch.com/llms.txt > Use this file to discover all available pages before exploring further. # DHIA Testing Overview for Dairy Goats > Dairy Herd Improvement Association (DHIA) testing is the gold standard for objectively measuring dairy goat performance. Whether you milk five goats or Canonical source: the standalone **Goat Health & Husbandry KB** (herdmate.io ecosystem). Sync changes there to avoid drift. # DHIA Testing Overview for Dairy Goats Dairy Herd Improvement Association (DHIA) testing is the gold standard for objectively measuring dairy goat performance. Whether you milk five goats or fifty, DHIA data helps you make better breeding, culling, and management decisions by providing reliable production records, component analysis, and genetic evaluations. This guide explains how the program works, what it costs, and how to use the data to improve your herd. ## What Is DHIA? DHIA is a national cooperative program administered through local and regional affiliates that provides standardized milk production testing for dairy animals, including goats. The program has been operating in the United States for over a century and is the official source of production records recognized by breed registries and genetic evaluation programs. For goat producers, DHIA testing is coordinated through the American Dairy Goat Association (ADGA) in partnership with the Council on Dairy Cattle Breeding (CDCB, formerly USDA AIPL) and local DHIA affiliates. The data collected feeds into national genetic evaluation systems, making your individual herd records part of a broader effort to improve dairy goat genetics across the country. ### Why It Matters * Official production records are required for ADGA performance awards and star designations * Genetic evaluations (PTAs) are calculated from DHIA data, enabling informed sire selection * Somatic cell count monitoring helps detect subclinical mastitis before it becomes a costly problem * Objective data replaces guesswork when making culling and breeding decisions * Production records increase the value of animals when selling breeding stock ## How Testing Works ### Test Plans DHIA offers several test plan options that vary in cost, frequency, and who performs the testing: **Owner-Sampler (OS) Plans:** * The herd owner collects milk samples and records weights on test day * A DHIA laboratory analyzes the samples for components and somatic cell count * Most affordable option, typically tested monthly * Records are official for ADGA recognition when following proper protocols **Supervisor (S) Plans:** * A trained DHIA supervisor visits the farm on test day to collect samples and record weights * Highest accuracy and credibility for production records * More expensive due to the supervisor's time and travel * Required for certain advanced recognition programs **AM/PM Testing:** * On alternating test days, only the morning or evening milking is sampled (not both) * The laboratory uses conversion factors to estimate 24-hour production * Reduces labor on test day while maintaining reasonable accuracy * Widely used by goat producers who find twice-daily sampling burdensome ### What Happens on Test Day 1. **Each doe is milked individually** and her milk is weighed separately (using a calibrated scale or DHIA-approved meter) 2. **A representative sample** is collected from each doe's milk using a DHIA-provided sample vial 3. **Sample vials are labeled** with the doe's identification number and the test date 4. **Samples are shipped** to a DHIA-approved laboratory in an insulated container, usually the same day 5. **Results are returned** within 1 to 2 weeks, either by mail or through an online portal Testing typically occurs once per month throughout the lactation, beginning shortly after kidding and continuing until dry-off. ## What the Tests Measure ### Milk Weight The most basic measurement: how many pounds of milk each doe produces on test day. Monthly test-day weights are used to calculate projected 305-day lactation totals, which are the standard metric for comparing production across does, herds, and breeds. ### Butterfat Percentage and Yield Butterfat content is a key component for cheese making and reflects the nutritional density of the milk. DHIA reports both the percentage of butterfat and the total pounds of fat produced. Nigerian Dwarf and Nubian goats typically produce higher butterfat percentages than Swiss breeds like Saanens and Alpines, but total fat yield depends on both percentage and volume. ### Protein Percentage and Yield Milk protein (primarily casein) is the component most directly tied to cheese yield. Like butterfat, DHIA reports both percentage and total pounds. Protein content is influenced by genetics, stage of lactation, and nutrition. ### Somatic Cell Count (SCC) Somatic cell count measures the concentration of white blood cells and epithelial cells in the milk. Elevated SCC is the primary indicator of udder inflammation, usually caused by mastitis. * **Goat SCC is naturally higher than cow SCC** and varies more with stage of lactation and parity * Counts below 1,000,000 cells/mL are generally considered acceptable for goats, though lower is better * A sudden spike in SCC for an individual doe warrants further investigation (California Mastitis Test, culture) * Monitoring SCC trends over time is more useful than any single test-day reading * DHIA calculates a Somatic Cell Score (SCS), a log-transformed value that is easier to compare and is used in genetic evaluations ### Other Measured Components Depending on the laboratory and test plan, you may also receive data on: * Lactose percentage * Milk urea nitrogen (MUN), which reflects protein-to-energy balance in the diet * Other solids content ## Genetic Evaluations from DHIA Data One of the most powerful benefits of participating in DHIA is the connection to the national genetic evaluation system. Production records from DHIA-tested herds across the country are used to calculate Predicted Transmitting Abilities (PTAs). ### What Are PTAs? PTAs estimate the genetic merit an animal is expected to transmit to its offspring for specific traits. PTAs are expressed as deviations from the breed average: * **PTA Milk**: Predicted pounds of milk a sire's daughters will produce above or below the breed average * **PTA Fat**: Predicted pounds of butterfat above or below average * **PTA Protein**: Predicted pounds of protein above or below average * **PTA SCS**: Predicted somatic cell score (lower is better, indicating healthier udders) ### How PTAs Are Used * Compare bucks objectively, regardless of which herds their daughters are in * Identify does with high genetic merit for retention in the breeding program * Track genetic trends in your herd over time * PTAs become more reliable as more daughters contribute data (measured by the reliability percentage) ### ADGA Genetic Evaluations ADGA publishes genetic evaluations twice per year. These evaluations are available to ADGA members and incorporate DHIA data from all participating herds. You can look up PTAs for individual bucks and does on the ADGA Genetics website. ## How to Enroll ### Step 1: Contact Your Local DHIA Affiliate DHIA is organized through regional affiliates. Contact ADGA or your state's dairy herd improvement organization to find the affiliate serving your area. Some regions have dedicated small ruminant programs. ### Step 2: Choose a Test Plan Select the testing option that fits your budget, herd size, and goals. For most small to mid-size goat herds, the Owner-Sampler AM/PM plan offers the best balance of cost and value. ### Step 3: Set Up Animal Identification Every doe on test must be permanently and uniquely identified. ADGA-registered animals already have registration numbers. All animals must be identified consistently on every test day. ### Step 4: Obtain Testing Supplies Your DHIA affiliate will provide or sell you the necessary supplies: sample vials, shipping containers, scales or meters, and record forms or digital apps. ### Step 5: Schedule Your First Test Testing usually begins within 30 days of kidding for each doe. Work with your affiliate to establish a monthly testing schedule. ## Cost Considerations DHIA testing costs vary by region and test plan but typically include: * **Enrollment fee**: A one-time or annual fee to join the program (typically $25 to $75) * **Per-sample laboratory fee**: Usually $2 to $5 per sample per test day * **Supervisor fee** (if applicable): $50 to $150 per farm visit, depending on travel distance * **Supplies**: Sample vials, shipping materials, and scale calibration For a herd of 10 does tested monthly on an Owner-Sampler plan, expect to spend roughly $300 to $600 per year. This investment is easily justified by a single improved breeding decision or early mastitis detection that saves a doe's udder and production. ### Offsetting the Cost * ADGA star milker awards and performance pedigrees increase the sale value of breeding stock significantly * Early detection of subclinical mastitis prevents costly production losses * Data-driven culling decisions improve feed efficiency by removing low producers * Sire selection based on PTAs compounds genetic improvement year over year ## Using DHIA Data for Herd Improvement ### Monthly Test-Day Management * Review each doe's production trend. A sudden drop may indicate illness, feed problems, or management stress. * Compare individual SCC values to the doe's previous tests. Rising SCC on consecutive tests warrants a mastitis check. * Track days in milk for each doe to ensure you are comparing animals at similar lactation stages. ### Lactation Records and Benchmarking * Use completed 305-day lactation records to rank does within your herd * Compare your herd averages to ADGA breed averages to gauge where you stand * Set realistic improvement targets based on your current data ### Breeding Decisions * Breed your highest-PTA does to the highest-PTA bucks you can access * Use PTA SCS to select for mastitis resistance alongside production traits * Retain daughters from your best genetic crosses and evaluate their first lactations on DHIA test * Over time, DHIA data creates a detailed genetic picture of your herd that no amount of visual evaluation can replicate ### Culling Decisions * Cull does that consistently fall in the bottom 10 to 20 percent of your herd for production * Factor in SCC history: does with chronically elevated SCC are costing you milk quality and potentially spreading infection * Use economic analysis (feed cost per pound of milk produced) to identify animals that are not paying their way