Milk recording agencies Munster Bovine and Progressive Genetics recently introduced a new lifetime summary report in the milk recording report.
While primarily designed to aid farmers to identify the most profitable cows in the herd, the report is also extremely useful from a herd health perspective, as it groups cows based on their somatic cell count (SCC).
Speaking at a Munster Bovine webinar last week, Rosarii O’Connor said that the lifetime report will help farmers to identify the good, average and not so good cows in the herd based on their lifetime margin over costs.
The lifetime margin includes the costs during the dry period and the margin is expressed on a euro margin per day
Each herd is categorised based on milk yield and cows are assigned a cost category based on the month of calving. The lifetime margin includes the costs during the dry period and the margin is expressed on a euro margin per day.
The report is colour-coded, with the top 20% cows identified in green, average in white and bottom 20% marked with red.
Speaking on the webinar, new Munster Bovine CEO Doreen Corridan suggested that farmers should consider culling their red cows and replacing them with much better-quality replacement heifers. The report should be used as a comparison within the herd and not to compare performance across herds.
The new report also helps to identify cows suitable for selective dry cow therapy. Cows are assigned to four colour-coded categories.
Green cows have an SCC of less than 200,000 at the current and all previous milk recordings in that lactation. If the report is the first recording of that lactation, green cows had an SCC of less than 200,000 at the last recording before drying off.
The advice is to protect these cows from becoming infected. Some or all of the cows in this group should be eligible for selective dry cow therapy.
Recently cured cows are given a blue colour. These cows now have an SCC of less than 200,000 but had a previous milk recording in that lactation greater than 200,000. If this is the first recording after calving and if they had an SCC of greater than 200,000 at the last recording in the previous lactation, they are also considered to be cured.
Recently infected cows are given an amber colour. These have an SCC of greater than 200,000 at the current test but tested less than 200,000 at the previous test. The target is to have less than 7% of new infections at any time.
The advice is to use a California Mastitis Test (CMT) test these cows as soon as possible to identify and treat the infected quarter as prompt treatment will result in a better outcome.
It’s also important to prevent these cows from infecting other cows in the herd.
Persistently infected cows are those that have a SCC of greater than 200,000 at the current milk recording and were over 200,000 at the last milk recording also. These cows are labelled red on the report.
The target is to have less than 8% of the cows in the herd with a persistent infection.
The report also estimates the contribution that these individual cows are making to the bulk tank SCC. In some cases, there could be cows contributing 20% or more to the bulk tank SCC.
The advice for these cows is to try to prevent the spread of infection to clean cows through cluster-dipping or pre-spraying. Consider culling if more than one quarter is infected and not responding to treatment. Another option is to dry off infected quarters or to give an extra long dry period to allow the infection to cure.
Speaking at the webinar, Denis Howard, vet with Munster Bovine, said the most important thing farmers can do is to protect their clean cows from contracting mastitis and developing high SCC as we head into the autumn.
“The next thing is to identify the high-SCC cows for culling. So if they can’t be cured, particularly the ones that weren’t cured in the previous dry period and have a very bad history of SCC, they’re not going to cure so you have to start thinking about moving them on.”
He suggests cows that are recently infected and have had a reasonably good history with SCC should be considered for a long dry period of about three months combined with a long-acting dry cow tube.
He also recommends building up data on the herd by CMT-testing and taking samples from high-SCC cows which can be tested for sensitivity to drugs and allow for a better decision to be made with their vet on which dry cow tube to use.