Normal Variation Expected in Butterfat Tests
Normal Variation Expected in Butterfat Tests
Variation is normally seen in milk butterfat tests. This variation is seen between morning and night milkings for the same day and between different days. An example of the normal variation in milk production and milkfat test for two first-calf heifers (6-10 weeks into lactation) over a 6-day period is shown in the table below. Each heifer was fed the same amount of feed each day in two equal feedings. Cows were milked in a stanchion barn with a milk bucket at 6:30AM and 5:00PM. Although these data are from a small number of cows, they do show the normal variation seen in milk production and butterfat test.
Day | Milk Production (lbs) | Fat % |
---|---|---|
Cow # 8907 | ||
Monday | 69 | 3.76 |
Tuesday | 67 | 3.24 |
Wednesday | 67 | 3.46 |
Thursday | 68 | 3.02 |
Friday | 66 | 3.31 |
Saturday | 72 | 3.21 |
Cow #8907 | ||
Monday | 59 | No samples |
Tuesday | 61 | 4.08 |
Wednesay | 61 | 3.49 |
Thursday | 60 | 4.05 |
Friday | 61 | 3.62 |
Saturday | 64 | 4.48 |
Fat % listed is a weighted average of AM and PM milkings which were collected separately.
Author: Donna Amaral-Phillips