Selective Dry Cow Therapy – Dairy Farmers making life saving changes!

By Tom Murphy, B&T Dairy Adviser, Teagasc, Galway/Clare

Regulatory changes to veterinary medicine legislation governing Dry Cow Therapy came into law in January 2022. The new changes are designed to protect human health against antimicrobial resistance (AMR). AMR or antibiotic resistance has evolved over time, resulting in reduced effectiveness at treating disease, due to misuse and overuse of the antibiotics that we ourselves and our animals depend on. The new legislation tells us that we need to reduce our use of antibiotics in animals and in particular in relation to mastitis control, especially at drying off. We can only administer antibiotic tubes to Dairy Cows at drying off when it is absolutely necessary. This relatively new approach is selective and demands that each cow is assessed and treated individually. The new concept is termed Selective Dry Cow Therapy or SDCT.

The Dairy farmers I work with have been preparing for these changes for a few years now, and the majority are conscientiously proactive in adapting to the change on their own farm ahead of enforcement. Training and demonstrated best practice has been provided at on-farm workshops run throughout the country by teams of industry technicians and professionals.  These workshop teams were organised by Animal Health Ireland (AHI) in conjunction with Teagasc and the Dairy Co Op Processors in each region. A successful SDCT approach requires engagement in these four key areas

1. Understanding the regulatory changes- the reason, the practical requirements and the expected outcomes
2. The management of the cow before and after drying and management of the dry cows environment/housing
3. The role of the farmer’s Vet and Agricultural Advisor and their involvement in planning the SDCT
4. The essential practical aspects to the drying off procedure

The starting point for Selective Dry Cow Strategy requires an individual risk assessment of each cow in the herd.  Based on this, cows at drying are treated with tubes in either of two ways

• Teat sealer tubes only - used on suitable cows, or
• Dry cow antibiotic tubes –used only on cows which absolutely need it

Information on individual cows is collected from regular milk recording results and related ICBF reports, records of all mastitis cases during the lactation, previous treatment outcomes, milk quality data (including somatic cell count (SCC), bacterial culture and antibiotic susceptibility testing) and individual California Milk Test (CMT) results. Milk recording is now an essential requirement and farmers who do not milk record are at a huge disadvantage.

Correct management of the cow in the lead up period to dying off will ensure that she is dried in the correct Body Condition Score (BCS) of 2.75 to 3.25, so that she subsequently calves in a healthy state at the desired BCS of 3.25 to 3.5. An adequate Dry period ensures that the cow will calve in the correct BCS, provided she is fed silage or forage of suitable quality. A successful dry period should result in a reduction of a cows SCC. Also, when the down time or dry period is sufficient, milk yield often improves in the following lactation. A well-managed environment (clean farm roadways, collecting yards, accommodation and dry well aerated cubicles & housing) is essential in minimising contamination of the cow’s udder before and after drying.

Farmers can get a free dry cow consultation with their Vet by contacting AHI and having the required criteria to qualify. Cows deemed to be largely infection free are selected for teat sealer only. Cows with evidence of infection during their previous lactation are selected for antibiotic tubes. The Vets role can include observation of the farmers drying process (first 2 to 3 cows), and giving feedback on relevant suggested improvements. In conjunction with the farmers Agricultural Advisor and Co-op Milk Quality Advisor, the relevant reports can be interpreted and the cows assigned to either treatment. Typically cows are Hygiene scored. Also, the management of the herd and the cow housing and environment can be assessed, with suggested recommendations for positive changes.

Evolving experience of SDCT has shown that herds with a bulk tank SCC of <200,000 in the previous 12 months should be using dry cow sealers only on some of the herd. Milk Recorded herds with at least 4 whole milk recordings in the lactation year give a full picture of the SCC status of each cow. Individual cows with a consistently low SCC (say <100KSCC, a lower/very low level is chosen in year_1) in all tests are candidates for sealers only.  Selected cows must not have had a case of clinical mastitis during the year, and selected mature cows should have shown a good response to the previous year’s dry cow treatment.

Preparation is key when it comes to the physical process of drying cows. Apart from the herd management factors already mentioned, some operations should be carried out in the weeks prior to drying. Ideally all tails should be clipped and any excessive hair/dirt removed from the cows udder areas. Preparation involves planning and selecting cows for drying in groups. Cows getting sealers only should be dried in a separate group and on a different day to a group of cows treated with antibiotics. These cows should be identified and clearly marked in advance. The physical aids and essentials (include clean apron, box of disposable latex gloves, surgical spirit/teat wipes/cotton wool, paper towels, marking spray/marking tape, reading glasses, headlight, builders belt, relevant tubes) should be left ready in advance.

Poor outcomes have resulted where too many cows are dried together by a single operator. Ideally, the group of cows for drying (maybe one parlour row) should be milked last at the morning milking, and retained in a clean collecting pen. It is recommended that the operator(s) wash & finish the milking process and eat a good breakfast before putting the cows back into the parlour for tubing. The process of infusing tubes requires patience, skill and above all else a meticulous approach to hygiene. Teat ends must be spotless. A less than thorough approach can result in the introduction of infection to an otherwise healthy udder. Sealer tubes act to seal the teat and prevent infection entry during the dry period- and the sealant must be infused into the teat preventing it escaping up into the udder. Antibiotics should on the other hand be massaged up into the udder. A clockwise process of cleaning teat ends with alcohol wipes should be followed by an anticlockwise process of tube infusion to minimise contamination risk.

Ideally, the dried cow should spend up to 2 weeks in a clean outdoor paddock (or a very clean/dry/airy shed) before housing proper. Accurate record keeping is essential to prevent any future risk of bulk milk contamination and to assess the success or otherwise of the given treatment.

Although this is only a brief overview of the drying process and management on today’s dairy farm, it shows the level of expertise, education, skill and resilience fostered by our dairy farmers in producing safe and healthy dairy products for us all.