Cell counts rise year on year as work-force falls
By Marianne Curtis
CELL counts have risen nationally each month for the third consecutive year, with higher cow numbers being managed by the same workforce to blame, according to National Milk Records.
In 1999 and 2000 average annual cell count for NMR recorded cows was 168,000 cells/ml and 175,000 cells/ml, respectively. For the first six months of this year, cell counts appear to have declined, with an average of 161,000, but this doesnt represent the whole picture, according to NMR market development manager Mike Blanshard.
"During March and April, foot-and-mouth meant we couldnt go on farms to record. Producers had the option of recording cell counts themselves, but those most keen on reducing cell counts are likely to have been the ones submitting samples, so this may have resulted in a lower average national figure. Also, this figure doesnt take into account part of the usual summer peak."
Peak cell counts occur in the summer months – when many autumn calving cows are in late lactation – and also show a rising trend, says Mr Blanshard (see table). "We expect cell counts to be lower in summer due to reduced mastitis incidence when cows are at grass. However, there are many late lactation cows in herds pushing up bulk cell counts." He advises drying them off a couple of weeks early rather than risking bonus payments."
With the OTMS scheme closed, larger numbers of cull cows continuing to be milked could also be contributing to higher averages this year, he adds.
Reasons for annual rising trends are unclear, but fewer staff looking after more cows could be a contributing factor, warns Mr Blanshard. "Cell counts were consistently declining until 1999, however, this trend has reversed over the past few years. When herds are close to the 150,000 mark, where bonus payments of 0.2-0.3p/litre kick in, it is worth putting in extra effort to keep them low."
Identifying high cell count cows is key, according to Maurice Allen, who runs On-Merits milk testing laboratory at Yattendon, Berks. "It only takes a small number of cows with high cell counts to raise the bulk average to more than 250,000. Pick out these cows and involve the vet in discovering offending pathogens, so appropriate treatment can be administered." *
NMRaverage June somatic cell counts 99-01
Year 000 cells/ml