When Bulk Milk Cell Counts are elevated there is plenty of incentive to reduce them – but what are the options?
Cows with subclinical mastitis infections have cell counts above 250,000 cells/ml, but no visible changes in the milk.
The question is how to remove the cells from the vat (and infections from the cows) most effectively.
• Treatment during lactation is NOT generally recommended. It has a relatively low chance of success and is expensive (milk discarded and antibiotic cost).
• Culling is a very expensive option unless the cows have chronic infections (high cell counts in two lactations with Dry Cow Treatment in-between) or have other reasons to leave the herd.
Antibiotic Dry Cow Treatment at drying-off is the best approach.
Whatever the approach to removing infections, it is essential to minimise spread to clean cows by hygiene at milking and 100% coverage of teats with teat disinfectant.
Identifying the infected cows
• Herd Testing provides Individual Cow Cell Counts (ICCCs) regularly during lactation.
Cows with any cell count above 250,000 are likely to be infected.
Diverting milk from these cows to feed calves for sale is also an option for some farms.
Treatment during lactation – usually not recommended
• Antibiotic treatment for subclinical infections during lactation usually has a low chance of success. It is just not possible to keep enough antibiotic in the udder for long enough. The costs in antibiotic and discarded milk are usually too high for the likely benefits, and there is increased risk of antibiotic contamination.
• The current recommendations are NOT to attempt treatment of subclinical cows
(with cell counts above 250,000 cells/ml, but no visible changes in the milk) except in specific circumstances.
For example herds with the majority of infections due to Strep agalactiae and possibly Strep uberis may see economic benefits from treatment during lactation. This should be assessed, based on cultures and economic analysis, in conjunction with your vet.
Antibiotic Dry Cow Treatment
• Most cows will cure infections over the dry period if they have sufficient time
(minimum of 6 weeks) and are treated with Antibiotic Dry Cow Treatment. Note, some cows are less likely to respond – especially older cows with high cell counts that have been present for two lactations.
• Early drying-off of high cell count cows that are in later lactation may be a good approach to decreasing Bulk Milk Cell Counts.
than usual and you should consider a blanket approach to Antibiotic Dry Cow
Treatment (all quarters of all cows at drying off).
• It is likely that cows will be at higher risk of new infections during the dry period and the use of a Teat Sealant to reduce this risk should be seriously considered.
Culling – a final step
A small number of high cell count cows can have a significant effect on Bulk Milk Cell Count level and milk quality payments. Chronically infected cows are likely to be a source of bacteria for other cows. Culling cows with chronic infections helps protect the healthy, young cows which are the future of the herd.
• Although culling is important in mastitis control, it is an expensive option. Farm cell count problems are seldom solved by culling alone. Failure to prevent new infections
will mean that other cows quickly take their place at the top of the high cell count list.
Candidates for culling are cows that have:
• 3 clinical cases of mastitis in the one lactation
• chronic infection – a cell count above 250,000 in two lactations with Dry Cow Treatment in-between