Dry Cow Therapy
The 4 goals of Dry Cow Therapy (DCT)

The dry period is the most crucial time in your mastitis management programme. You have an opportunity to ‘recharge’ the entire herd.

1. Cure existing infections at dry off.

Reducing the number of cows carrying infections through the dry period not only prevents these flaring up into clinical infections but limits the source of contagious bacteria to other cows in the herd.

Cepravin has been shown to have high cure rates in New Zealand conditions4, with an overall cure rate of 82% including 79% cure of S. aureus.

2. Prevent new infections at dry off and throughout the dry period.

Dry period mastitis is difficult to treat, is costly and time consuming and can have long term effects on the cows’ production.

Prevention is vital, especially where it is difficult to inspect the cows regularly during the dry period.

In a New Zealand trial,4 Cepravin® DCT was associated with a hastened formation of the keratin plug in the teat canal – this adds further protection alongside the long-acting antibiotic effect.

3. Protect against mastitis and reduce new infections around the calving period.

Mastitis around calving is common. The cow’s defences are down around the calving period and there is plenty of exposure to environmental bacteria. Cepravin has been shown to significantly reduce mastitis at this busy time. 4,5

4. Reduce Somatic Cell Count (SCC) and mastitis into the subsequent lactation.

Studies have shown that up to half of the clinical cases seen in early lactation are due to infections picked up during the dry period. These infections can be carried through unnoticed until the cow is in milk when they flare up into clinical cases. Cepravin has been shown to reduce the incidence of mastitis in the first three to five months of lactation. 4,5

The SCC is a reflection of the number of cows infected in the herd. The prevention and cure of infections given by effective DCT will significantly reduce this. 4,6

Selection of Dry Cow Therapy (DCT)

The selection of DCT must be in consultation with your veterinarian; this gives them a chance to review your mastitis situation and discuss all aspects of mastitis control during the season as well as selecting the type of DCT that would best suit your situation.

4
Williamson J.H. et al. (1995). The prophylactic effect of a dry-cow antibiotic against Streptococcus uberis. NZVJ.
5
Woolford M. W. et al. (1998). The prophylactic effect of a teat sealer on bovine mastitis during the dry period and the following lactation. NZVJ.
6
McDougall S. (2003). Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation. NZVJ.
LONG-ACTING VERSUS SHORT-ACTING
The use of long-acting Dry Cow Therapy (DCT) can improve the outcome for all the goals of DCT
Cure of existing infections

The reason DCT is more effective than treatment during lactation is because the antibiotic can be kept in contact with bacteria for a longer period. With long-acting DCT, the concentration of antibiotic is kept high enough to kill bacteria for longer, especially deeper in the udder tissues, giving a better chance of cure.

For example, trial work9 has demonstrated an increased cure using Cepravin compared with a shorter-acting cloxacillin DCT. Overall, Cepravin cured around 10% more of the cows treated.

Long-acting protection during the dry period

A long-acting DCT such as Cepravin maintains protective levels of antibiotic throughout the dry period. While the concentration of antibiotic drops quite quickly after dry off, the depletion of drug slows dramatically in the later dry period, owing to changes in the physiology of the gland. At 10 weeks after dry off the levels are still well above those needed for protection against Staphs and Streps. 10

Having the drug present for an extended period of time prevents flare ups of clinical mastitis throughout the dry period. This is especially important if the cows are not able to be observed closely. In a New Zealand trial Cepravin reduced the incidence of dry period mastitis compared to no treatment from 12.3% to 1.2% during the dry period and at calving. 4

" Cepravin
cured around
10% more9 "
The impact of long-acting Dry Cow Therapy (DCT) continues into the following lactation

New Zealand studies have also demonstrated the effectiveness of Cepravin into the next lactation (not just during the dry period and at calving).

This is because many of the clinical cases we see during early lactation are due to bacteria picked up in the dry period. Ruakura studies showed a significant reduction in clinical mastitis in cows treated with long-acting DCT. In one study there was a reduction of 52% up until March,4 while another5 demonstrated a reduction of 50% in first five months of lactation.

Reduction of SCCs

Long-acting DCT has been shown to reduce the BTSCC of the herd. New Zealand studies have shown that increasing the percentage of the herd treated with a long-acting DCT decreases the SCC.7 Local studies showed a significant decrease in SCCs in quarters treated with long-acting DCT compared with untreated controls (a reduction of 30% in cows4 uninfected at dry off and 49% in infected cows). In a study run at Massey University,11 the cell count at the start of the season was significantly lower in cows treated with Cepravin therapy (190,000 cells/mL) than in those treated with a shorter-acting cloxacillin treatment (389,000 cells/mL).

4
Williamson J.H. et al. (1995). The prophylactic effect of a dry-cow antibiotic against Streptococcus uberis. NZVJ.
5
Woolford M. W. et al. (1998). The prophylactic effect of a teat sealer on bovine mastitis during the dry period and the following lactation. NZVJ.
7
McDougall S. (2003). MSD Animal Health data on file
9
Shephard et al. (2004). A comparative field trial of cephalonium and cloxacillin for dry cow therapy for mastitis in Australian dairy cows. AVJ.
10
Harris et al (1976). Cephalosporins in the treatment and prevention of mastitis. Vet Record.
11
Parkinson T. et al. (2000). Comparative efficacy of three dry-cow antibiotic formulations in spring calving in New Zealand dairy cows. NZVJ.
" Cepravin
reduced the
incidence of
dry period
mastitis from
12.3% to 1.2% 4 "
WHAT ABOUT THE USE OF TEAT SEALANTS?

The combination of a short-acting Dry Cow Therapy (DCT) and internal teat sealant has been shown to improve results compared with short-acting therapy alone.12 However, New Zealand trial work5 has shown that this combination does not improve on the efficacy of Cepravin used by itself.


3
McDougall S. (2003). Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk somatic cell count during the subsequent lactation. NZVJ.
5
Woolford M. W. et al. (1998). The prophylactic effect of a teat sealer on bovine mastitis during the dry period and the following lactation. NZVJ.
12
Laven R and Lawrence. (2008). Efficacy of blanket treatment of cows and heifers with an internal teat sealant in reducing the risk of mastitis in dairy cattle calving on pasture. NZVJ.

If farmers are using a long-acting DCT already and feel that they need further protection at the end of the dry period, it has been shown that the addition of an internal teat sealant to the long-acting DCT can improve the result. For example, it has been shown that a teat sealant plus Cepravin provides an advantage over Cepravin alone13.


13
Bradley A.J. et al. (2010) .The use of a cephalonium containing dry cow therapy and internal teat sealant, both alone and in combination. J Dairy Sci.