What is being assessed?
The assessor will evaluate a random sample of cattle in the milking herd for:
- Body condition score
- Injuries: Hocks, neck and knees
- Lameness
The assessment is designed to provide producers with a benchmark of how their cattle score to track their own improvement over time, and provide them with an analysis to compare their farms results to their peers. It should highlight what they are doing well and any areas requiring some improvement.
will be assessed similarly to hock injuries, with one notable difference: any swelling of a knee or the neck will receive a score of "R” Requires corrective action.
SAMPLE SIZE
| Average # of cattle in milking herd | Sample size: minimum # of cattle for assessment | Approximately every ____ animal |
|---|---|---|
| <20 | 14 | All to every 2nd |
| 30 | 18 | 2nd |
| 40 | 21 | 2nd |
| 50 | 23 | 2nd |
| 70 | 27 | 3rd |
| 90 | 29 | 3rd |
| 100 | 30 | 3rd |
| 150 | 33 | 5th |
| 250 | 37 | 7th |
| 350 | 38 | 9th |
| 450 | 39 | 12th |
| 550 | 40 | 14th |
| 700 | 40 | 18th |
| >1000 | 5% | 20th |
DFC has developed the sample size calculator to ensure that results from assessing the sample are representative of the herd and are statistically valid. The sample size calculator is based on a statistically representative sample size calculator, except for herds over 1,000 cows, which need to have more animals assessed. This was done to ensure extra credibility for large herds. Smaller herds have a larger percentage of animals assessed than larger herds, but using a percentage across herds does not provide statistically valid results. The smaller the herd size, the more animals you need to assess to determine the herd’s results. This also mitigates the risk of a few random animals drastically affecting the Cattle Assessment results. For example, if the 5% sample size was applied across herds, a 30-cow herd would only have 2 animals assessed. If one had hock injuries, the herd’s injury rate would be 50%! The larger sample size for smaller herds ensures more accurate results.
Keep in mind that accurately assessing the sample of your herd will require an investment of your time. Time required to assess the sample of your herd will be discussed while scheduling your visit with the assessor.
