Selective dry cow therapy: without blanket antibiotic treatment

What is Selective Dry Cow Therapy (SDCT)?

Selective Dry Cow Therapy (SDCT) is a modern approach to managing mastitis in dairy cows during the transition from lactation to the dry period. The key difference compared to the traditionally common practice of preventative antibiotic administration at dry-off is that antibiotics are not given to all cows automatically—only to those where it makes sense based on objective criteria.

Cows with no signs of infection receive only an internal teat sealant—a physical barrier that prevents pathogens from entering the udder during the dry period. Cows with a confirmed subclinical or clinical infection receive targeted antibiotic treatment, ideally based on an antibiogram.

The selective approach is now legislatively supported in the EU—Regulation (EU) 2019/6 restricts the preventative use of antibiotics in groups of animals without a confirmed infection. This means that blanket antibiotic treatment of all cows at dry-off is no longer in line with standard veterinary practice under EU rules.

Selective vs. Blanket Dry Cow Therapy — A Complete Comparison

Blanket Dry Cow Therapy (BDCT) was the standard practice for decades—every cow received an antibiotic dry cow (DC) product at dry-off regardless of her health status. The selective approach significantly re-evaluates this practice.

Studies published in the Journal of Dairy Science repeatedly confirm that properly implemented selective dry cow therapy does not increase the incidence of mastitis in the subsequent lactation compared to blanket dry cow therapy. The key is proper cow selection based on proven criteria.

When to Dry Off a Cow

The standard timing for drying off is 6–8 weeks (42–60 days) before expected calving. This period is critical for the cow, as it allows for:

Regeneration of mammary gland tissue
Treatment of existing infections (selectively based on diagnostics)
Preparation for the next lactation—colostrum production and hormonal changes
Metabolic rest for the dairy cow after a demanding lactation

When to Dry Off: Earlier or Later?

Low-yielding cows (under 12 kg/day): can be dried off abruptly
High-yielding cows (over 25 kg/day): gradual milk yield reduction 7–10 days before dry-off, ideally by adjusting the feed ration
Cows with recurrent mastitis: dry off earlier (60–70 days) to extend treatment duration
Primiparous cows and cows with subclinical mastitis in late lactation: dry off at the recommended time, but with antibiotic administration

When to Dry Off a Cow Without Antibiotics?

A cow is a suitable candidate if she meets most of the following criteria:

SCC < 200,000 cells/ml in the last 1–3 milk recordings
No clinical mastitis during the last lactation
No significant teat end damage
Negative bacteriological finding (e.g., using the ClearMilk test)
Low risk at the herd level (low bulk tank SCC, good hygiene)

In an average Czech herd, 60–75% of cows meet these criteria. This represents the actual potential for antibiotic savings.

Selective Dry Cow Therapy Criteria

To decide which cow receives an antibiotic and which receives only a teat sealant, we use three layers of information:

Somatic Cell Count (SCC)

The primary routine indicator. We monitor:

Current SCC in the last recording prior to dry-off
SCC trend over the last 3 recordings
Peak SCC during lactation

Threshold values vary depending on the protocol, but typically:

PSCC below 200,000 in all recent recordings → no antibiotics (sealant only)
SCC above 200,000 in at least two of the last three recordings → confirmatory ClearMilk test
SCC above 500,000 → ClearMilk test or laboratory bacteriological examination + antibiogram → targeted antibiotic therapy

Mastitis History

The second filter—even a cow with low SCC may harbor a hidden chronic infection:

Clinical mastitis during current lactation → with antibiotics (even with low SCC)
Recurrent mastitis (3+ episodes) → with antibiotics + extended therapy or consider culling
No mastitis during lactation → no antibiotics

Bacteriological Examination (Culture)

The most accurate parameter, critical for deciding whether to use an antibiotic preparation. A milk sample is collected 3–4 days prior to dry-off and processed via the ClearMilk test or laboratory culture:

NNegative result + low SCC → no antibiotics
Positive result (any pathogen) → with antibiotics targeted based on an antibiogram
Detection of Staphylococcus aureus or Streptococcus uberis → always with antibiotics + consider an extended treatment protocol

Decision diagramDecision diagram

Step-by-Step Procedure

Selective dry cow therapy is not just an "antibiotic yes/no" decision—it is a standardized protocol that must be understood by the entire milking team.

WEEK -2

Prior to Dry-Off

Identification of cows scheduled for dry-off—lactation week 45+
Data collection—current SCC, mastitis history, clinical anamnesis
Classification of cows into groups: no antibiotics / targeted antibiotics / culling candidates

WEEK -1

Preparation

Gradual reduction of milk yield in cows producing over 20 kg/day (reduce concentrates, maintain forage)
3–4 days prior to dry-off—collecting milk samples for bacteriological examination (ClearMilk test)
Evaluation of ClearMilk test results, ordering an antibiogram for positive cases if necessary
Preparation of DC products (antibiotics) and teat sealants—checking expiration dates, storing in the refrigerator

DAY D0

Dry-Off Day

Final milking using standard routine—pre-dipping, dry wiping
Thorough treatment of the cow following final milking: Disinfection of the teat end using a single-use disinfectant wipe / alcohol swab Application of products in this sequence: Cows receiving antibiotics: DC antibiotic first, then internal teat sealant (sealant must always be administered after the antibiotic!). Cows without antibiotics: internal teat sealant only.
Post-dipping with a protective teat barrier film
Moving the cow to a clean, freshly bedded area for dry cows

WEEK +1

Monitoring

Monitoring—routine udder checks (swelling, pain, clinical mastitis)
In case of clinical symptoms, consult a veterinarian immediately—treatment is possible even during the dry period

WEEK +5 TO +8

Pre-Calving

Preparing the cow for calving—moving to the maternity pen, body condition scoring (BCS)
Post-calving: initial CMT test on all quarters, testing the first milk yield (after colostrum)

Teat Sealants - Internal vs. External

A teat sealant is a mechanical barrier that prevents bacteria from entering the udder during the dry period. There are two types:

Internal Teat Sealant (ITS)

Mechanism: a paste made of bismuth (subnitrate) or other mineral components applied intramammarily via a teat cannula
Duration of protection: throughout the entire dry period (60 days) until the first milking
Efficacy: up to a 70% reduction in new infections compared to unsealed cows
Application: must be performed under aseptic conditions, using a single-use tube per quarter
Product examples: OrbeSeal, Boviseal, ClearSeal
Disadvantages: higher cost, requirement for precise application, necessity to manually strip out after calving

External Teat Sealant

Mechanism: a silicone or latex coating applied to the external surface of the teat
Duration of protection: 5–14 days (gradually sloughs off)
Efficacy: lower than ITS, much less commonly used today
Application: simpler, lower cost
Disadvantages: inconsistent protection, requires reapplication

Recommendations

For selective dry cow therapy in a modern herd, internal teat sealants are the standard. External sealants are used only marginally today (e.g., during cow transit or as a supplement to ITS).

Important Note

An internal teat sealant is NOT an antibiotic. It has no milk withdrawal period if applied correctly. After calving, it is manually stripped out prior to attaching the milking unit—it appears as a white to yellowish paste and must be completely evacuated.

Antibiotics at Dry-Off

If antibiotic administration is indicated in a dairy cow, the appropriate dry cow (DC) product must be selected using a selective protocol.

Types of DC Products in the Czech Republic

Note: 3rd and 4th generation cephalosporins belong to Category B under Regulation (EU) 2019/6 - they are administered under indication restrictions only when Category C/D medications are insufficient.

Selection Based on Antibiogram

Antibiotic selection should always be determined based on an antibiogram from a bacteriological examination.

Withdrawal Period After Dry-Off

Every DC antibiotic product is subject to a withdrawal period for both milk and meat, governed by the instructions provided in the package leaflet.

Economics of Selective Dry Cow Therapy

The selective approach does not only mean reduced antibiotic consumption—it also delivers a concrete financial impact.

Annual Savings for a Typical Farm

For a herd of 200 dairy cows with a lactation length of 305 days (approx. 200 dry-offs/year):

Antibiotic savings: approx. 200 × 80 CZK = 16,000 CZK/year
Administrative savings (less antibiotic reporting): an additional ~5,000 CZK/year
Reduced risk of major penalties for non-compliance with applicable legislation
Reduction in resistant bacteria within the herd: long-term strategic value—fewer cases of untreatable mastitis

Risk of Method Failure in Selective Dry Cow Therapy

Selective dry cow therapy must not be implemented without proper diagnostics and protocols. Omitting antibiotics in a cow with undiagnosed subclinical mastitis significantly increases the risk of a clinical episode in the subsequent lactation. A single case of clinical mastitis costs €200–€400.

Common Errors During Dry-Off

Application without disinfection

If you do not disinfect the teat end prior to applying a DC product or sealant, you risk introducing a new infection directly intramammarily. Result: mastitis during the first 2 weeks after dry-off.

Incorrect sequence - sealant before antibiotic

If you apply the teat sealant before the antibiotic, the antibiotic will not enter the udder. Always follow: disinfection → antibiotic → teat sealant → post-dipping.

Non-standardized protocol across the team

If every milker uses a different procedure, the quality of selective dry cow therapy declines. Recommendation: written SOPs, annual training (1× per year), and an internal audit at least once a year.

Omitting diagnostics

Selective dry cow therapy without diagnostics is not selective—it is random. Without monitoring SCC, culture, and antibiograms, it is impossible to properly decide whether to use antibiotics and which ones to select.

Short dry period

A dry period of less than 40 days is insufficient for mammary gland tissue regeneration. High-yielding cows must have their feed ration gradually reduced 1–2 weeks before planned dry-off to trigger a drop in milk production.

Poor hygiene in the dry cow environment

Wet, dirty bedding during the dry period is a primary source of environmental infections (E. coli, Klebsiella spp.). Selective dry cow therapy without a high-quality environment = high risk of postpartum mastitis.

Applying teat sealant without subsequent removal

An internal teat sealant must be manually stripped out after calving before attaching the milking unit. Incomplete removal = sealant in the milking system + milk contamination.

Recurrent Mastitis at Dry-Off — What to Do

Some cows suffer from recurrent mastitis specifically during the dry period or shortly after calving. The most common causes:

Staphylococcus aureus

This pathogen invades udder tissue cells (intracellularly) and is difficult to eradicate with standard DC therapy. Recommendations:

MALDI-TOF + antibiogram for strain identification and susceptibility testing
Extended treatment—in indicated cases following consultation with a veterinarian
If recurrent 3+ times in the same quarter → consider culling (the cow serves as an infection reservoir with a low probability of cure)

Streptococcus uberis

Frequently causes chronic colonization of the udder. Recommendations:

e.g., 1st generation cephalosporin (adjust the antibiotic protocol based on an antibiogram)
Environmental hygiene control (S. uberis is frequently an environmental pathogen from the surrounding environment)
Bacteriological examination post-calving in the subsequent lactation

Mycoplasma bovis

Untreatable with antibiotics. Upon confirmed detection: culling, isolation, milking parlor disinfection.

FAQ - Frequently Asked Questions

Selective dry cow therapy (SDCT) means administering intramammary antibiotics only to cows that actually need them - based on somatic cell count (SCC), mastitis history, and bacteriological examination. Cows without signs of infection receive only an internal teat sealant. This approach reduces antibiotic consumption by 30–50% and complies with Regulation (EU) 2019/6.

The standard timing is 6–8 weeks (42–60 days) prior to expected calving. A short dry period (under 40 days) is insufficient for udder tissue regeneration, while a long dry period (over 70 days) increases the risk of obesity and postpartum metabolic issues, unnecessarily reducing herd productivity. For high-yielding cows, milk yield should be gradually reduced 7–10 days before dry-off.

A cow can be dried off using only an internal teat sealant (without antibiotics) if she meets all of the following criteria: SCC below 200,000 cells/ml in the last 1–3 milk recordings, a negative result from a ClearMilk test or laboratory culture, and no signs of teat end damage. In an average herd, 60–75% of cows meet these criteria.

Blanket Dry Cow Therapy (BDCT) administers antibiotics to every cow regardless of her health status—which currently conflicts with Regulation (EU) 2019/6. Selective Dry Cow Therapy (SDCT) makes individual decisions based on SCC, mastitis history, and bacterial culture. SDCT reduces antibiotic consumption by 30–50%, lowers resistance risk and costs, without increasing mastitis incidence in the subsequent lactation.

Cows with a positive bacteriological finding require antibiotics. Confirmed isolation of Staphylococcus aureus or Streptococcus uberis requires special attention, as do a history of recurrent mastitis and damaged teats. For positive cultures, antibiotics are selected based on an antibiogram.

Optimally 42–60 days. A shorter period does not allow enough time for mammary gland tissue regeneration, while a longer period increases the risk of obesity, metabolic problems, and paradoxically, an elevated SCC. For high-yielding cows (>25 kg/day), the feed ration should be gradually reduced 1–2 weeks before dry-off to decrease milk yield.

A teat sealant is a mechanical barrier that prevents bacteria from entering the udder during the dry period. An internal teat sealant (ITS) is a bismuth-based paste applied intramammarily via a teat cannula—it provides protection throughout the entire dry period (60 days) and is the standard in modern selective dry cow therapy. An external teat sealant is a silicone coating on the teat skin—it is less effective.

An internal teat sealant (ITS) is an intramammarily applied paste that protects for the full dry period (60 days) and reduces new infections by up to 70%. It is manually stripped out after calving. An external teat sealant is a silicone/latex coating applied to the outside of the teat that protects for 5–14 days (gradually sloughs off). An internal sealant is the standard for selective dry cow therapy, whereas external sealants are rarely used.

Antibiotic selection depends on the antibiogram result. For Staphylococcus aureus, cloxacillin (Orbenin DC) is typically used. For Streptococcus uberis, 1st generation cephalosporins (Cepravin DC) are used. For broad-spectrum coverage, combination products (Bovaclox DC) are selected. 3rd and 4th generation cephalosporins belong to Category B under Regulation (EU) 2019/6 and should only be administered exceptionally.

The standard milk withdrawal period for DC antibiotic products is 28–55 days depending on the specific product, plus 96 hours (4 days) post-calving. In practice, with a dry period of 60 days + 4 days post-calving, most DC products easily comply with withdrawal period requirements. Always refer to the package leaflet of the specific product.

By implementing selective dry cow therapy with diagnostics (ClearMilk test approx. 180 CZK / test) and targeted antibiotic administration, you can save approximately 140 CZK per cow, representing a savings of around 40–45% in dry-off costs compared to blanket antibiotic therapy. For a herd of 200 dairy cows, this translates to a direct savings of approximately 28,000 CZK per year on antibiotics. Additional benefits include reduced administrative burden, lower risk of penalties under Regulation (EU) 2019/6, and long-term mitigation of antimicrobial resistance—preserving antibiotic efficacy for situations where treatment is truly essential.

Recurrent mastitis during the dry period most frequently indicates a chronic infection with Staphylococcus aureus or Streptococcus uberis. Recommendations: (1) perform MALDI-TOF pathogen identification and determine an antibiogram, (2) consider extended therapy (5–8 days instead of standard 4), (3) inspect the hygiene of the dry cow environment, (4) consider culling if there are 3+ episodes in the same quarter—a chronically infected cow serves as an infection reservoir for the herd.

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Criterion	Blanket Dry Cow Therapy (BDCT)	Selective Dry Cow Therapy (SDCT)
Who receives antibiotics	Every cow	Only cows with confirmed infection
Who receives teat sealant	Optional	All cows
Antibiotic consumption	High (100%)	30–50% (50–70% savings)
Compliance with EU 2019/6	❌ No	✅ Yes
Risk of mastitis in subsequent lactation	Higher	Lower
Need for diagnostics	None	Key (SCC, culture, antibiogram)
Antibiotic costs	Higher	30–50% lower
Risk of resistance development in the herd	Higher	Lower

SCC	Clinical mastitis during lactation	Culture	Decision
< 200 000	No	Negative	No antibiotics (sealant only)
< 200 000	Yes	Negative	No antibiotics (sealant only)
< 200 000	No	Positive	Antibiogram – targeted antibiotics
< 200 000	Yes	Positive	Antibiogram – targeted antibiotics
> 200 000	Yes / No	Negative	Targeted antibiotics – based on previous findings
> 200 000	Yes / No	Positive	Antibiogram – targeted antibiotics

Active Substance	Typical Products	Target Pathogens
Ceafalonium	Cepravin DC	Gram-positive, some Gram-negative
Cloxacillin	Orbenin DC	Gram-positive (S. aureus, S. uberis)
Penetacillin + Framycetin	Ubrostar DC	Gram-positive and Gram-negative
Ampicilin + Cloxacilin	Bovaclox DC	Broad spectrum
Cefquinom	Virbactan DC	Broad spectrum (indication restrictions!)