The Agri-Food and Biosciences’ Institute (AFBI) is highlighting the risk of toxic mastitis in dairy cows at drying-off.
In one Co. Tyrone case, four cows from a batch of 13, which had been dried-off, died four to five days later.
Two of the cows were submitted for post-mortem examination and toxic mastitis was present in multiple quarters of each cow.
In a separate Co. Armagh case, six cows died within 11 days of drying off. One of the cows aborted five days after drying off and died five days later.
When examined at the AFBI post mortem centre, there was toxic mastitis in multiple quarters.
Toxic mastitis
Insufficient attention to hygiene and cleanliness is likely to have been a significant factor in these and in other similar incidents recently examined by AFBI veterinarians.
To avoid such detrimental outcomes, drying-off procedures should be carefully planned. This means that preparation for drying off should begin in the weeks before animals leave their milkng groups.
According to AFBI veterinarians, a 60-day dry period is considered ideal and the timing of drying off should reflect this.
Cows should be in appropriate condition at drying off and body condition scores between 2.5 and 3.5 are considered optimal and will reduce the risk of metabolic problems in the subsequent lactation.
Levels of concentrate feeding should be reduced in the week prior to drying off in cows producing more than 10kg of milk per day.
Normal milking intervals should be maintained before drying off and it is not recommended to practice ‘once-a-day’ milking as part of the drying-off routine as this may actually increase the risk of mastitis.
Antimicrobials
Antimicrobials are essential to both veterinary and human medicine to treat infectious diseases.
The continued availability of all existing antimicrobial classes and the development of new ones for veterinary use are essential to maintain the health and welfare of animals and the protection of public health, according to AFBI.
Veterinarians have said that the blanket use of intra-mammary antibiotics at drying off is not sustainable.
So, careful choices must be made in selecting which cows are dried off with intra-mammary antibiotic and teat sealant and which cows are dried off with teat sealant only.
It is recommended to involve your vet in deciding which cows to dry off with sealant only and which cows require sealant and antibiotic.
Cows which have had a somatic cell count (SCC) below 200,000 over the last three milk recordings and which have not had a case of clinical mastitis in the last three months are suitable candidates for teat sealant only.
In cows with recent high cell counts or a case of mastitis in the last three months, antibiotic is indicated but selection of the antibiotic in the dry cow tube should be based on effectiveness against the bacteria responsible for the mastitis.
Good technique at drying off is critical. Sub-optimal technique not only increases the risk of mastitis in the immediate period post drying off, it also increases the risk of coliform intra-mammary infections into the next lactation.
