Selective dry cow therapy
The use/overuse of antimicrobials and particularly antibiotics in farm animals is increasingly being highlighted in the media, together with concerns about possible transfer of antibiotic resistance from farm animals to people. The current level of antibiotic use in dairy cattle in the UK in 2024 is estimated to be 12.7mg/population correction unit, (Kingshay Dairy Antimicrobial Focus Report 2024), which is well below the 17.9 target set out by RUMA (Responsible use of medicine in agriculture). RUMA – Responsible Use of Medicines in Agriculture Alliance. However, there is a wide range in antibiotic at farm level.
Selective dry cow therapy is one possible strategy to reduce antibiotic use in dairy cows, albeit injectable antibiotics account for the largest quantity of antibiotics administered on most dairy farms. (Lactating and dry cow tubes contain small amounts of antibiotic). Antibiotics are normally only administered when an animal is considered ‘sick’, but this is not the case with dry cow tubes, where blanket treatment has been the norm for many years. Reducing dry cow antibiotic use through ‘selective dry cow therapy’ is a relatively easy and justifiable strategy to “use as much antibiotic as necessary, but as little as possible”. Click on the pdf’s below for further information on ‘Selective Dry Cow Therapy’ and the results in the CAFRE Dairy Herd.
This strategy has been implemented in the CAFRE Dairy Herd since 2016. Selection criteria for dry cow tubes were agreed in conjunction with the farm veterinary practitioner. Individual cow milk recording information and clinical mastitis records are used in the decision-making process. The criteria set for cows to receive antibiotic dry cow therapy, along with internal teat sealants were somatic cell counts below 200 for the last 3 milk recordings before drying off and no cases of clinical mastitis during that time frame. These criteria are applied to both heifers completing their first lactation and older cows. It is reckoned that most animals with a SCC under 200 are free from udder infection and most animals over 200 are infected, but this is not an exact science. Monthly milk recording data combined with records of clinical mastitis cases are usually considered adequate to make informed decisions about what cows should or should not receive dry cow antibiotics. However, the further away the results from the last milk recording are the chances increase that a decision at cow level may be wrong, but this is not a life/death decision and cows with an increased SCC from last recording can still recover during the dry period even if not receiving dry cow therapy.
Moving forward, it is possible to treat cows at drying off at the quarter level, i.e. testing individual quarters for SCC level and tubing accordingly. However, to do this requires an instrument that can read SCC levels on the spot and most farmers are unlikely to invest in this sort of technology.
The success/failure of dry cow treatments can be easily assessed by comparing the SCC at dry off with the SCC at first milk recording in the next lactation. Cows dried off with a low SCC (no dry cow tubes) should calf in with a low SCC, (Target 90%) – Dry period protection). Cows dried off with a high SCC (dry cow tubes administered) should calf in with SCC below 200, (Target 85% – dry period cure). These 2 parameters (dry period protection and dry period cure) are very easily measured and are a good way to assess management of dry cows across the dry period. The high-risk periods for infection are just after drying off and just before calving.
Hygiene is key for drying off cows irrespective of what treatments are administered. Drying off should be carried out as a separate task, not during milking, ideally with 2 people if possible. See the video below for more details. If hygiene is not up to standard, a very sick/dead cow within a few days can be the result. However, this need not be the case if correct procedure is carried out. CAFRE never had to deal with this situation in 10 years of implementing selective dry cow therapy in the herd, even when students were involved (under supervision).
Watch the video for further information on selective dry cow therapy.
