Mastitis Control through Dry Cow Therapy
A cow’s lactation begins at the time she’s dried off rather than when she calves. Proper management of dry cows often is neglected on many dairy farms. Dry cows often are placed in a back pasture and ignored, and subsequently are underfed. On other farms they remain with the milking herd and may be overfed, especially if they enter the milking parlor and consume left -over grain, or if com silage is available free-choice. Proper dry cow management is important in preparing cows for the next lactation. Many disorders (e.g., milk fever, abomasal displacements, retained placenta, uterine infections), lowered milk production, and clinical mastitis can be avoided. How the dry cow is managed also may affect the health and performance of the newborn calf.
Dry cow management includes attention to proper procedures for drying-off cows, feeding a special ration, and concern about the cow’s environment. Breeding and mastitis problems can result from infections developed during this time. Cows are most susceptible to new mastitis infections during the first two weeks of the dry period, the two :weeks before calving, and the two weeks after calving. Bred heifers are prone to new mastitis infections throughout pregnancy, but especially during the last 2 weeks before calving. Separate dry cows from the milking herd. When left with the milking herd, dry cows have access to com silage or high quality legume silage and may become over conditioned or prone to other metabolic disorders, including increased “downer” cows or milk fever, ketosis or acetonemia, displaced abomasum, retained placenta and metritis, and coliform mastitis. During the next lactation, fat cows lose very little body weight, and milk yield peaks at only 60-70 lb. daily for Holsteins rather than over 100 lb. Excessive energy consumption results in a buildup of fatty tissue in the liver which interferes with normal metabolic processes. The damage may be permanent. During the early part of the lactation, high-producing cows do not consume sufficient feed to meet their nutrient requirements. Milk production peaks at 4-6 weeks after calving; maximal feed intake occurs at 9-10 weeks. The extra energy needed for milk production is supplied by breakdown of body fat.
Mastitis is a disease of great economic consideration in buffaloes, which is characterized by the inflammation of the parenchyma of the mammary glands. Mastitis is a multifactorial disease and bacterial pathogens play an important role in the occurrence of the disease. The maximum chances for getting the new bacterial infections are during the dry period. During early dry period and at the end of the dry period mammary glands are highly susceptible for getting the new intramammary infections. Dry cow therapy is an effective technique to remove the prevailing intramammary infections and to inhibit the occurrence of new cases of mastitis, post-partum. The choice of dry cow antibiotic therapy should be done in such a way that it is effective against the prevailing environmental and coliform pathogens. The use of teat seals as a prophylactic measure of treatment is gaining popularity because through the use of internal teat seals great success has been achieved and there is no concern of antibiotic resistance, which is a burning issue now-a-days. Dry cow therapy is better than lactation therapy for treatment of mastitis because dry cow therapy has higher cure rates, reduction in antibiotic residue in milk and it is a cost effective therapy as compare to lactation therapy.
Mastitis is one of the greatest problems of bovines faced by milk industries because it causes huge economic losses due to losses in milk production by discarding of milk from affected quarters and veterinarian’s cost. Mastitis is characterised by inflammation of the parenchyma of the mammary glands, various physical and chemical changes in the milk and pathological changes in the glandular tissue. Approximately 140 microbial species, subspecies and serovars have been isolated from bovine mammary gland. Among microbial species various types of bacteria, viruses, fungi and algae have been identified as mastitis causing pathogens. However most of the mastitis causative agents in India are Staphylococci spp., Streptococci spp. and E. coli.
Drying-off
The cow’s udder needs time to rest and then regenerate new milk secreting cells. The cow’s body needs time to restore body energy and nutrient reserves. A summary of DHI records shows that the dry period should be at least 40 days long, preferably 50-70 days, with greatest milk yields during the next lactation occurring after 60 days dry. It’s been suggested that first lactation cows should have a 65-day dry period. Cows dry less than 40 days produce lower milk yields during the next lactation. Dairy farms should set aside one day a week for dryingoff cows. They should check their breeding records to determine which cows will calve within 50-70 days. They should not skip a week or cows will end up with short dry periods. In addition, when cows are treated with an antibiotic for mastitis at drying -off, a minimum dry period of 50 days is recommended to avoid antibiotic residues in milk after the cow freshens. Any Holstein cow producing less than 20 lb per day should be dried off; the chance of infection increases as production level declines. Dry cows up abruptly by discontinuing milking, dry treating, and feeding only hay and water. Cows should not be milked once-a-day or every-other-day over a short time period. Cows should be watched for several days. If they show signs of mastitis (swelling) or leaking milk, milk out and treat a second time after one week.
New bacterial infections during dry period
Non lactating ‘dry’ period is the specific period between two active lactating phases and the changes in mammary gland occurs dynamically both in structure and function. Dry period is responsible for adequate proliferation and differentiation of the mammary secretory epithelium for the optimum synthetic and secretory function in the ensuing lactation of the cows. There are three stages of the dry period: 1) period of active involution; it begins with cessation of milking, 2) period of steady state involution; it represents the time when the mammary glands are fully involuted, 3) period of colostrums formation and the initiation of lactation. Mammary glands are highly susceptible for new intramammary infections during the early dry period. Because after cessation of milking several changes may affect susceptibility of mammary glands to new intramammary infections: a) termination of flushing effect of milking leads to bacterial colonization in teat canal, b) the increased intramammary pressure cause leakage of milk and the penetration of the bacteria to teat canal occurs, c) during early involution the defence mechanism of the mammary gland are at low level. During the second stage the mammary glands are resistant to the new infections mainly due to the physical barrier of the keratin plug which effectively seals the streak canal. Again, the susceptibility for the new infections increases in the third stage as the keratin plug breaks down and the leukocyte function is impaired. Therefore, by preventing the new intramammary during dry period greatly helps in reduction of new cases of mastitis after the parturition.
DRY COW THERAPY AND ITS AIM
Dry cow therapy is the use of antimicrobial therapy at the end of lactation. It is one of the key steps in mastitis control programs and has become the most effective and widely used control method for dry cows. Dry cow therapy aims at removing the prevailing intramammary infection and inhibiting the new infections.
Preparations for the dry cow therapy
The standard method for cessation of lactation (drying off) for industry is abrupt cessation of milking, by which milking is stopped on the day scheduled for dry-off (all cows are usually scheduled on the same day each week for drying off) and this helps in facilitation for administration of dry cow intramammary antibiotics. Abrupt cessation of milking leads to higher new intramammary infection rate in the dry period compared to intermittent cessation, although the increase in prevalence is most evident in cases that are not treated during dry period. The best approach to dry off cows therefore, is intermittent milking. As the cow is susceptible for the new intramammary infections in initial weeks of dry period by environmental pathogens and in last weeks by environmental and coliforms pathogens. Therefore, the dry cow therapy should be extended over the whole dry period. Therefore, dry cow antibiotic therapy requires good activity against Staph. aureus including βlactamase producing strains, Staph. uberis, Strep. dysgalactiae, Strep. agalactiae, and if prophylaxis against the summer mastitis is required , therapy should also be effective against Arcanobacterium pyogenes. Therefore, the widely used intramammary injections contain narrow spectrum penicillins (penicillin, cloxacillin, oxacillin and nafcillin), cephalosporins and spiramycins. Regulation in the duration of the effect of the antibiotic can be done by pharmaceutical manipulation of the intramammary drugs, e.g. precipitating the antibiotic, dissolving it in a slowly absorbing oil or micro-encapsulation. The use of effective dry cow products results in 70-98 per cent elimination of existing infections. However, elimination of Staph. aureus is less successful. It is important that the instructions mentioned on the label should be followed carefully for the recommended dosage level, required withdrawal period, storage guidelines and expiry dates. The idea of use of teat seals as a prophylactic measure of treatment has gained the popularity over the use of antibiotics in farm animals. The external teat seal is a latex barrier teat dip that forms a physical seal between the teat and environment, thus reduces the incidences of new intramammary infections. An internal teat seal containing bismuth subnitrate was developed in 1970s. Internal teat seals achieve the much greater success as compared to external teat seals in reducing the new intramammary infection up to 90 per cent during the dry period. Quarters with external teat seals have been found to be positive for the lower level of infection as compared to unsealed quarters but the external teat seals are not effective as compared to internal teat seals. Internal teat seals remain lodged in the lower teat for at least three to four weeks following drying-off. Incorporation of antibiotics or other suitable antimicrobials into teat seal can prevent inadvertent contamination during infusion of teat seal in teat canal, therefore now a day the teat seal with antimicrobial are also used for improving the safety of the product.
Dry cow treatment procedures’ should be carried out as follows-
– Completely milk out the udder.
– Immediately following teat cup removal, dip all teats in an effective teat dip. Generally used teat disinfectants are; 0.55 per cent chlorhexidine, initial application of 2 per cent sodium hypochlorite and gradually increase its concentration up to 4 per cent, and 0.1 per cent iodophore. The gold standard teat dip is an iodine-based teat dip in 10 per cent glycerine.
– Dry the teat dip. If necessary, remove excess dip from teat ends by a clean single service paper towel.
– By scrubbing, disinfect each teat end for a few seconds with a separate alcohol-soaked cotton swab. Start with the teats on the farther side of the udder from you and after that work to the nearer side.
– With a single-dose syringe of a recommended dry cow treatment, infuse each quarter. First infuse in the teats on the near side of the udder. For infusion, use the partial insertion method of administration into the teat streak canal. Preferably, a modified infusion cannula should be used for the infusion of the intramammary preparations.
– Dip all teats in an effective teat dip immediately following the treatment.
ADVERSE EFFECTS OF DRY COW THERAPY –
– The random antibiotic therapy kills the normal bacterial flora of the teat canal and the teat end, thus allowing pathogenic and antibiotic-resistant bacterial colonization in the area.
– Antibacterial use over a large-scale increases the selection pressure to spreading of antibiotic-resistant bacterial strain.
– Irritation of teat ends.
BENEFITS OF DRY COW THERAPY
– Higher cure rates are found as compared to the lactation therapy.
– Higher dose of antimicrobials can be used safely.
– Longer retention time of antimicrobial occurs in udder as compared to the treatment during the lactation therapy.
– Reduction in incidence of clinical cases of mastitis.
– Reduction in contamination of milk with antimicrobial residue.
– Minimum cost of treatment of mastitis in one quarter in a buffalo may be approximately Rs. 3000 including cost of medicines, veterinarian consultancy and loss of milk as compare to approximately Rs. 1500 for the dry cow therapy.
CONCLUSION
During dry period mammary glands are at a great risk of getting new intramammary infections. Dry cow therapy by use of intramammary antibiotics is very effective for removing the prevailing intramammary infection and inhibiting the new infections for control of mastitis. Teat seals now-a-days are gaining popularity as a prophylactic measure of treatment as they have no problem of antibiotic resistance and antibiotic residues in milk. However, few adverse effects are associated with dry cow therapy, but higher cure rates are found through dry cow therapy and it is a cost effective way for the control and treatment of mastitis as compared to the lactation therapy
FAQ ON MASTITIS IN DAIRY ANIMALS
Q.1 :What is mastitis?
A :Mastitis is inflammation of udder/ mammary gland characterized by change in milk.
Q.2 :What should I do after onset of Mastitis?
A :If it is possible, milk sample for culture sensitivity test (CST) (to know the sensitive antibiotics) should be submitted before starting treatment. Broad spectrum antibiotic and supportive treatment with consultation of veterinarian should be given to the animal. If antibiotics are already being given to the animal, the milk sample should be submitted 4 days after end of therapy.
Q.3 :How should I take the milk sample for testing to the laboratory?
A :You should collect the milk sample in sterilized test tubes or in sterilized vials. The test tube should be labeled appropriately. At least 5 ml of milk sample should be submitted to the laboratory as early as possible. If delay is expected, samples should be kept in ice-container. Udder should be cleaned and soaked with neat piece of cloth. Teat orifice should aseptically be cleaned. Before taking sample in test tube, first few strippings (1-2 strippings) should be discarded.
Q.4 : What should I do to avoid infection during dry period?
A : As there is no specific dry cow therapy available in India, one should take care of the managemental aspects. If prevalence of infection in the herd is high, all the animals at drying- off should be injected with Intra-mammary infusions.
Q.5 : What should I do to avoid recurrence of mastitis?
A : Individual animal should be treated and her udder immunity enhanced by using mineral mixture of standard quality, cleaning of udder before milking, milking of infected teat at the end and teat dipping after milking.. Milk samples should be tested regularly after 15 days using SLS paddle test. The positive animal’s milk samples should be tested for CST in the laboratory. Treatment of sub-clinical case is more desirable.
Q.6 : Why does the swelling of udder occur just after calving while there was no sign during late pregnancy?
A : There are chances of subclinical mastitis at drying-off and during dry period. This infection gets flared-up after parturition due to certain stress factors.
Q.7 : What is the treatment of udder/teat fibrosis?
A : Udder/ teat fibrosis occurs as a result of chronic infection. Treatment of udder and teat fibrosis in that particular lactation can result into resolution to some extent, but chances of recovery may be expected in the next lactation when new lacteal tissue formation will ensue.
Q.8 : There is problem of warts over the teat of animals. How to treat it?
A : Please, Consult nearest available qualified veterinarian for treatment.
Q.9 : I have a buffalo which has developed sores at the base of teat since one month. Milk yield is normal. Advise me appropriate treatment.
A : This problem is usually chronic running for many months. The best treatment for this is to apply antiseptic solutions like Betadine/Povidine regularly. If no recovery occurs apply a powder mixed in equal parts containing boric acid, kaolin and zinc oxide once daily. The healing in such cases is slow and takes 3-4 weeks. Do not use antibiotics, which will increases the cost of treatment only.
Q.10 : What are the mastitis control measures?
A : The important features of a successful mastitis control programme are:
- Regular testing of animals for subclinical mastitis
- Adopt hygiene measures
- Post-milking teat dipping be adopted
- Follow Dry cow therapy
- Increase udder resistance to mastitis
Q.11 : What is Post-milking teat dipping?
A : The teats of all the lactating cows and dry cows (during first 10-14 days of dry period) are dipped regularly after every milking in a germicidal solution. The recommended teat dips are
- Iodine (0.5%) solution 6 parts + Glycerine 1 part
- Chlorhexidine (0.5%) solution 1 Litre + Glycerine 60 ml
The iodine teat dip is the best as it treats various types of teat lesions and injuries also.
Compiled & Shared by- This paper is a compilation of groupwork provided by the
Team, LITD (Livestock Institute of Training & Development)
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Reference-On Request.
