Larson Dairy Controlled Farm Comparison
The challenge
Larson Dairy considered its new well water generally good, although testing identified bicarbonate, manganese and hardness as the parameters noted as elevated. The farm wanted to determine whether a controlled water-treatment program could produce observable operational differences between similar cow groups.
The comparison
The robotic barn was divided into two pens served by two robots each. The farm described the groups as approximately 125 cows per side and balanced them as closely as practical for stage of lactation and starting milk production. One side received treated water while the other remained the control. Water meters and the farm control system recorded water use, and the robotic-milking system supplied production information.
- The treatment was gradually increased to the historical working level recorded in the source documents.
- The farm tracked milk production, water consumption, feed intake and cow weight.
- Somatic-cell counts could not be compared between groups because milk from the two groups was not separated into different bulk tanks.
Reported observations
| Milk production | The farm reported approximately 97 lb/cow/day for the treated group and 90 lb/cow/day for the control group – a difference of about 7 lb/cow/day during this evaluation. |
| Water intake | The owner reported that treated cows drank approximately 7 additional US gallons per cow per day. |
| Feed intake | The treated group reportedly consumed slightly more than 1 additional pound of dry matter per cow per day. |
| Equipment observation | The owner reported that the treated water tanks were easier to keep clean. |
| Follow-on observation | After the control group began receiving treatment, the farm reported an increase of approximately 2 lb/cow/day within the first 12 days. |
What this case teaches
This record demonstrates the value of testing water, establishing a comparison group and measuring water intake alongside production. It does not establish that the same response will occur on another dairy. Herd genetics, ration, stage of lactation, climate, housing, management and starting water quality can all influence results.
Evidence classification
Classification: Farm-controlled comparative evaluation with customer-reported observations. The records conflict on whether the trial lasted 61 or 71 days; the public page should state only January-April 2020 unless the original parties reconcile the duration.
Important notice
This historical farm evaluation was not a blinded, randomized or peer-reviewed scientific study. Results describe one dairy and are not a guarantee of milk, health or financial performance. Water treatment must be selected from current water analysis and farm conditions.