Up to 70% of all new intra-mammary infections are acquired during the dry period*1. The dry period is the main time at which mastitis infections are acquired on many Irish farms with infections entering the udder via the teat end. Although the infection is acquired during the dry period, it does not manifest itself as a case of mastitis (or subclinical mastitis) until lactation begins. We therefore can attribute many early lactation infections to infection acquired during the dry period.
What is the importance of the dry period?
During the dry period, a keratin plug forms in the teat canal*2 and acts as a natural defence mechanism to protect against bacterial infections. However, this natural protective mechanism is not always effective. Roughly a quarter of lower-yielding dairy cows may fail to develop a complete keratin plug in the dry period. Without this barrier, there is a greater risk of bacteria entering the udder*3.
How important is the dry period on my farm?
To determine the importance of the dry period on your farm, you will need records of both clinical mastitis in the first 30 days after calving and somatic cell counts at first milk recording.
1 Look at clinical mastitis incidence in first month of lactation:
- Interference level at more than one case in 12.
2 Look at cell counts after calving:
- Interference level at more than one case in 10.
If more than one in 12 cows develops clinical mastitis during the first month of lactation or more than one in 10 cows has a high somatic cell count at first milk recording, then addressing the dry period in the herd is likely to improve mastitis control.
How to achieve optimum results
1. Assess body condition
Aim for body condition scores of 2.75-3 at drying off and 3-3.25 at calving*4. Over-conditioned cows are at increased risk of negative energy balance in the transition period and this has a direct link with the immune function of the cow*5.
2. Ensure optimum hygiene at drying off
Drying off cows should be done as a separate job at the end of milking. The hygiene required at drying off is like the hygiene required prior to a surgical procedure. Teat ends must be
"surgically clean" prior to introducing antibiotic dry cow therapy or teat sealants to avoid introducing infectious pathogens when inserting the tube. For more information on the optimum dry cow technique, watch here:
3. Use Boviseal
Boviseal replaces the natural keratin plug and ensures the barrier against infection is present throughout the dry period preventing more than one in three cases of mastitis*6,*7. Not all teat sealants are the same. Farmers have relied on Boviseal for more than 15 years to prevent mastitis infections. Colloidal anhydrous silica is an essential component of Boviseal in the formulation. It gives body to the product and increases its viscosity. The combination of ingredients produces a seal of optimum character and consistency, proven to prevent new intramammary infections and reduce the incidence of clinical mastitis acquired during the dry period.
4. Manage the dry cow environment
After dry-off, cows should be kept in clean and dry environment. If they are going outside, ensure paddocks are clean and dry, eg not heavily soiled with manure, no bare ground and no exposure to dairy effluent. If indoors, the cubicles should be cleaned and limed twice daily. On many farms the attention is mainly focused on keeping the milking cows as clean as possible, but the same principle should also be applied to dry cow cubicle management.
5. Ensure hygiene at calving
Calving pens should be cleaned out regularly. It is a balance between providing cows with enough grip to get up and avoiding build-up of infection in the calving pen which can affect both udder and calf health. The bedded area for calving cows should be in the region of 15 sqm. If your knees are wet after kneeling, the bedding is not clean and dry enough for calving cows*8. If cows are calving outside, the calving area should be sheltered and well drained and must have minimal manure contamination. If water is visible on the surface or in your wellie prints, it is not dry enough for calving cows*9.
6. Involve your vet
Your veterinary surgeon can help you assess the importance of the dry period on your farm and advise on antibiotic dry cow therapy, along with drying off protocols using teat sealants.
*1. Green MJ et al (2002). Influence of dry period intramammary infection on clinical mastitis in dairy cows. J Dairy Sci. 85:2589-2599
*2. Paulrud, CO (2005). Basic concepts of the bovine teat canal. Vet Res Commun. 29:215–245.
*3. Dingwell RT et al (2004). Association of cow and quarter level factors at drying-off with new intramammary infections during the dry
period. Prev Vet Med. 63, 75-89.
*4. Finbar Mulligan, World Buiatrics Congress Proceedings (2012), Lisbon.
*5. Hammon, DS, Evjen, IM, Dhiman, TR, Goff, JP, Walters, JL (2006). Neutrophil function and energy status in Holstein cows with
uterine health disorders. Veterinary immunology and Immunopathology 113, 21-29
*6. Rabiee AR & Lean IJ (2013). The effect of internal teat sealant products (Teatseal and OrbeSeal®)* on intramammary infection, clinical
mastitis and somatic cell counts in lactating dairy cows: A meta-analysis. J Dairy Sci. 96:1–17
*7. Godden S et al (2003). Effectiveness of an internal teat seal in the prevention of new intramammary infections during the dry and
early-lactation periods in dairy cows when used with a dry cow intramammary antibiotic. J Dairy Sci. 86(12):3899-911