Table 1 Descriptive characteristics of cows with and without a clinical influenza diagnosis on a Midwest dairy farm, including non-affected cows on the day of the first clinical diagnosis in the herd (March 21, 2024), and affected cows when they were diagnosed by farm personnel between March 21 and April 13, 2024 (n = 3876)
From: The impact of highly pathogenic avian influenza H5N1 virus infection on dairy cows
Item | Cows without clinical Influenza diagnosis (n = 3099) % (number) | Cows diagnosed with clinical Influenza (n = 777) % (number) |
|---|---|---|
Lactation stage | ||
0–100 days in milk | 32.4% (1004) | 23.4% (182) |
100–200 days in milk | 29.5% (914) | 36.6% (284) |
>200 days in milk | 23.8% (739) | 39.9% (310) |
Dry period | 14.3% (442) | 0.1% (1) |
Lactation number | ||
1 | 34.6% (1073) | 20.6% (160) |
2 | 34.6% (1072) | 44.1% (343) |
≥3 | 30.8% (954) | 35.3% (274) |
Breed | ||
Holstein | 39.4% (1220) | 40.3% (313) |
Jersey | 21.9% (679) | 21.0% (163) |
Crossbreed | 38.7% (1200) | 35.3% (301) |
Milk production (kg/day)a | 34.6 ± 10.1 | 36.2 ± 9.2 |
Rumination (min/day)a | 403 ± 87 | 409.0 ± 80.1 |
Somatic cell count (cells/mL; log)b | 4.4 ± 1.3 | 4.4 ± 1.3 |
