DHIA Milk Test Guide: Preparation, Test Day & Understanding Results
DHIA (Dairy Herd Improvement Association) milk testing is the official, standardized system for measuring dairy goat production. Monthly test-day records become part of your does' permanent production history through ADGA, affecting their value, their offspring's value, and your herd's reputation. Whether you are testing for the first time or want to improve your test-day results, this guide covers everything from preparation to interpreting your numbers.
Why Test?
- Official production records: ADGA star milker designations (*M, *D) require official DHIA test data. These stars significantly increase a doe's value and her offspring's marketability.
- Breeding decisions: You cannot improve what you do not measure. Knowing each doe's actual production, butterfat, and protein lets you select your best genetics and cull your worst.
- Buyer confidence: Buyers pay premium prices for goats from herds with documented production. "My doe milks a lot" means nothing — "my doe produced 1,847 lbs at 5.2% butterfat on her 2nd lactation" means everything.
- Herd management: Monthly test data reveals trends you would miss otherwise — a doe whose production drops suddenly may have a health issue. SCC trends catch subclinical mastitis early.
How DHIA Testing Works
A certified DHIA supervisor visits your farm once per month (every 28 to 34 days) to observe and record milk production for each doe. The supervisor weighs each doe's milk and collects a composite sample for lab analysis. Results come back from the lab within 1 to 2 weeks.
Test plans
| Plan | Description | Cost |
|---|---|---|
| Standard (supervised) | DHIA supervisor observes both milkings (AM and PM) on test day. Gold standard for official records. | $3 to $8 per doe per test |
| Owner-sampler | You weigh and sample the milk yourself, following DHIA protocols. Supervisor may audit periodically. Less expensive but records carry less weight. | $1 to $3 per doe per test |
| AP/AM test | Supervisor observes one milking only (AM or PM, alternating months). Production is estimated for the unobserved milking using a formula. | $2 to $5 per doe per test |
Preparing for Test Day
The 12-hour rule
Test day measures what each doe produces in a defined time interval. For standard twice-daily milking, the goal is to have does milked as close to 12 hours apart as possible on test day. If you normally milk at 6 AM and 6 PM, maintain that schedule on test day.
If your normal milking times are uneven (say 5 AM and 4 PM — 11 and 13 hours apart), the lab adjusts the raw weights using time formulas. But the closer to 12/12 you can get, the more accurate your records.
Udder preparation (the weeks before)
If your does are not used to holding a full udder for exactly 12 hours, start adjusting your milking schedule 2 to 3 weeks before your first test:
- Standardize your milking times. Pick consistent AM and PM times and stick to them daily. Does adjust their production rhythm to your schedule within a few days.
- If milking once daily, you will need to switch to twice daily for test day (or use a once-daily test plan if available). Start milking twice daily at least 1 week before the test so does adjust.
- Practice the test-day routine. On test day, the supervisor needs to see you strip each teat, observe the milk, and weigh it. Practice this flow so it goes smoothly and quickly — stressed does let down less milk.
Udder fill for maximum recorded production
Your recorded production directly reflects how full the udder is at milking time. Some tips to ensure does show their best:
- Do not milk early. If you normally milk at 6 AM and the supervisor arrives at 5:30 AM, wait until 6 AM. Every ounce counts on official records.
- Feed well the day before. Does that are well-fed produce more milk. Make sure quality hay, grain, and water are available in the 24 hours before test day.
- Reduce stress. Do not move pens, introduce new animals, or change routine right before test day. Stress drops production.
- Milk completely. Strip out every last bit — the strippings are the highest-fat milk. Incomplete milking loses both volume and butterfat percentage on your records.
Test Day Procedure
- Supervisor arrives and checks that all does to be tested are identified (ear tags, tattoos, or collars).
- You milk each doe as normal. The supervisor watches and may assist with weighing. Each doe's milk is weighed separately on a calibrated scale (in tenths of pounds).
- Composite sample collected. The supervisor collects a small sample from each doe's milk into a labeled vial. This sample goes to the lab for component analysis.
- Both milkings recorded. AM and PM weights are recorded separately. The daily total is the sum of both milkings.
- Samples shipped to the lab. The supervisor ships all vials to the DHIA lab (usually the same day or overnight).
- Results returned. Lab results come back in 1 to 2 weeks, showing weight, butterfat %, protein %, SCC, and other components per doe.
Understanding Your Results
Key metrics on your test report
| Metric | What It Means | Good Target (dairy goats) |
|---|---|---|
| Milk weight (lbs) | Total daily production in pounds (AM + PM combined) | Breed-dependent: ND 1-3 lbs, standard 5-10 lbs |
| Butterfat % | Percentage of milk that is fat. Higher = richer milk, better for cheese. | 3.5-5% standard breeds, 5-8% Nigerian Dwarf |
| Protein % | Percentage of milk that is protein (mostly casein). Important for cheese yield. | 2.8-4.5% depending on breed |
| SCC (x1000) | Somatic cell count in thousands. Indicator of udder health. | Under 750K is healthy for goats |
| MUN | Milk urea nitrogen. Indicator of protein/energy balance in the diet. | 12-16 mg/dL is balanced |
| DIM | Days in milk — how many days since the doe freshened. | N/A — used for context |
Lactation records and star milkers
ADGA calculates official lactation records from your monthly test data. These records are expressed as total pounds of milk and total pounds of butterfat over a 305-day lactation (or actual days if shorter). To earn star milker designations:
- *M (Star Milker): Doe must meet minimum production thresholds for her breed on an official DHIA test. Requirements vary by breed — check ADGA's current standards.
- *D (Star Dam): Dam of a star milker. Earned automatically when a daughter achieves *M status.
- +B (Plus Buck): Buck whose dam is a star milker. Critical for marketing bucks.
These designations appear on registration papers and pedigrees, significantly increasing animal value. A doe with *M and a buck with +B are worth substantially more than unproven animals.
Improving Your Test-Day Numbers
- Nutrition: Feed quality directly affects production. Ensure adequate energy (grain), protein (alfalfa or high-protein hay), and minerals, especially during early lactation when production is highest.
- Consistency: Milk at the same times every day, not just on test day. Erratic milking schedules depress production.
- Health: Parasites, subclinical mastitis, and mineral deficiencies all reduce production. Stay on top of FAMACHA checks and health management.
- Genetics: Production is highly heritable. Breed your best producers to bucks from high-producing dams. Over time, genetic selection is the most powerful tool for improving test-day numbers.
- Freshen at the right time: Does that freshen in early spring (February-March) tend to produce more over their lactation than those that freshen in late spring, because they hit peak production during the lush pasture months.
Record milk tests digitally
Herd Manager's batch milk recording lets you log test-day weights for all lactating does on one screen in tenths of pounds (industry standard). DHIA test data including butterfat, protein, and SCC is tracked per doe with automatic lactation curve generation.
Try Herd Manager Free →