What to do with that continually elevating BMCC
Summer is the toughest time for farmers with a high BMCC. As production drops, the cell count rises even if there is no change in the level of mastitis in the herd.A herd with a cell count of 250,000 producing 18 litres in January will have risen to 375,000 by the time cows drop to 12 litres. This is because cows produce a fixed number of cells per day independent of production. As volume drops, the concentration of cells increase.
Previous newsletter articles have explained the effect of culling high cell counts on the BMCC. The message was that unless an individual cow has a continually elevated cell count and is a big producer, she will have little impact on the BMCC. In most herds it will require at least 3% of the herd to be culled to reduce the cell count by 30-40% (300,000 to 200,000). The increase in milk income due to a higher quality payment is in most factories about 3% difference. In herds where the BMCC is over 500,000 the penalties may be more severe. If your herd is in this category, it is advisable to discuss the available options with us.
A herd test in late summer or early autumn may identify a number of cows with elevated counts. Rather than drying off or culling these cows do the calculations on how many cows need to be removed. Remember if it is greater than 3% of the herd the drop in milk income will outweigh the benefits of higher quality. By next month, the BMCC may be higher again, so not only is production lower due to culled cows but milk quality is still not premium.
- Example: The effect of a high ICCC cow in a 200 cow herd.
- Herd BMCC with cow included 290,000
- Production of cow 12 litres
- Herd Average 17 litres
- Her ICCC 1.5 million
- Her contribution to herd BMCC 5,000
- Herd BMCC with cow removed 285,000
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