PRESENTATION
BROCHURE
ESSENTIAL G IDES ON CATTLE FARMING
Drying-Off Management Luis Miguel Jiménez Galán
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ESSENTIAL GUIDES ON CATTLE FARMING
Drying-Off Management
ESSENTIAL G IDES ON CATTLE FARMING
Drying-Off Management Luis Miguel Jiménez Galán
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7/6/18 15:06
AUTHOR: Luis Miguel Jiménez Galán. FORMAT: 17 x 11 cm. NUMBER OF PAGES: 82. NUMBER OF IMAGES: 100 approx. BINDING: softcover, wire-o.
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The objective of this guide is to describe the main events that take place during the dry period, both in the udder and in the cow, and to show how they can influence the subsequent lactation period. The book also provides basic guidelines for a proper drying-off technique and management of cows during this period in order to reduce the prevalence of intramammary infections and achieve optimal milk production.
Drying-Off Management
Presentation of the book The dry period is a decisive stage in the production cycle of a cow. When a cow reaches approximately 210 days of gestation, milk removal is halted so the dry period can start in order to increase milk production in the subsequent lactation. This phenomenon is known as the dry period. If a cow were not dried off, due to her genetic potential, she would continue producing milk for much longer, with the resulting loss of production in the subsequent lactation. During the dry period, a series of changes occur in order to prepare the mammary gland for a new lactation period. Both anatomical and physiological changes take place in the udder, which will increase in size due to the accumulation of milk in the alveoli, ducts and cistern. The secretory cells die and the secretory tissue and residual secretion are reabsorbed; this phenomenon is known as mammary involution. Then, at the end of the dry period, these secretory cells start to increase their secretory capacity by increasing in size and filling with fat and protein, which thus gives rise to the production of colostrum for the next lactation. The dry period is critical in terms of udder health since it is a time when the risk of intrammary infections increases. These infections may persist in the subsequent lactation and many of them will be the cause of clinical mastitis. The objective of this phase is to the keep the mammary gland free of infections. Everything will depend on the management strategies used at dry-off, as well as during the rest of the dry period. In addition, cows will experience changes not only in the udder, and feeding and management practices should therefore be adapted. All this will affect their welfare and undoubtedly their health too. This guide has several purposes. Firstly, it aims to describe the main events that occur during dry-off, both in the mammary gland and in the cow. Secondly, it shows how dry-off plays a role on the next lactation, since this practice has many associated risks that can greatly affect the animal’s health and production. Finally, this book intends to provide a practical view of what to do when drying off a cow to minimise intramammary infections in the subsequent lactation, as well as to increase milk production.
The author Luis Miguel JimĂŠnez GalĂĄn He graduated in veterinary medicine from the Complutense University of Madrid in 1992. He is the technical manager of SERVET TALAVERA S.L., a company specialised in mastitis and milk quality control and dedicated to developing and implementing integrated mastitis and milk quality control programmes since 1994, taking into account all the factors that may affect milk quality. He also works as a consultant for veterinary practitioners specialised in milk quality and the control of mastitis in Spain and other countries such as the United States, Argentina, Mexico, Colombia, etc. He organises annual seminars on dairy cattle in Talavera de la Reina, with a special emphasis on milk quality.
Drying-Off Management
He has been a speaker at conferences in Spain and in more than 15 other countries on topics related to milk quality, such as milking systems, cow comfort, milking routines, implementation of good practices, milk quality assessment and milk production, among others. He also participates in specialised internet fora and has taught courses on milking equipment and seminars on cow comfort. He is the author of articles for the National Mastitis Council and the International Dairy Federation, as well as for more generalist magazines. He was vice-president of the Spanish National Association of Specialists in Bovine Medicine (ANEMBE) from 2008 to 2016, and chairman of the milk quality committee from 2002 to 2016. He is a member of the National Mastitis Council (NMC), the American Association of Bovine Practitioners (AABP), the American Dairy Science Association (ADSA), and the International Dairy Federation (IDF). He is also a member of the IDF committee on animal health and the IDF project group Milking Time, created to measure the influence of milking machines on the teat.
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ESSENTIAL G IDES ON CATTLE FARMING
Drying-Off Management Luis Miguel Jiménez Galán
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Table of contents 1. Introduction The importance of the dry period Udder health Strategies Financial impact
2. Udder physiology during the dry period Mammary involution Active involution phase Steady state phase Colostrum production phase
Immunity in the mammary gland Active involution phase Steady state phase Colostrum production phase
3. Risk of intramammary infections Factors affecting susceptibility
5. Strategies to prevent new infections Drying-off methods Advantages and disadvantages of drying-off methods
Dry cow therapy Intramammary therapy Systemic therapy Blanket therapy Selective dry cow therapy
Teat protection Internal sealants External sealants
Nutritional management Effect of reduced dry matter intake
Immune system support Environmental control Pasture Cubicle housing Straw yard housing Compost bedded pack barns
Udder quarter-related factors
Precalving milking
Cow-related factors
Epidemiological control during the dry period
Herd-related factors
4. Welfare of the dairy cow Welfare of the dairy cow Consequences of drying-off Stress caused by pain Stress caused by nutritional changes Stress caused by heat
6. References
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Introduction
Drying-off management
The most significant aspect of these infections is their effect on milk production in the following lactation. Quarters infected during the dry period subsequently produce 35 % less milk than healthy quarters, and quarters cured during the dry period subsequently produce 11 % less milk than quarters that have never been infected (Fig. 3).
Figure 3. Milk production per quarter depending on their condition.
Milk production (%)
Financial impact 100 90 80 70 60 50 40 30 20 10 0
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Healthy Quarters cured during Infected quarters the dry period quarters
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INTRODUCTION
The financial impact of the dry period is very high, so management measures are required to reduce the prevalence of IMIs during this period and these should be included in an udder health programme. Implementation of strategies to achieve this requires knowledge of mammary gland physiology during drying-off, and in-depth understanding of epidemiology and the risk factors during the dry period.
The fundamental objective of the dry period is to achieve the lowest amount of IMIs to ensure a higher milk production in the subsequent lactation.
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Strategies to control IMIs ◗
Implement a dry period.
◗
Use dry cow therapy.
◗
Protect the teat with internal/ external teat sealants.
◗
Manage nutrition.
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Improve immunity.
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Manage the environment.
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Practice precalving milking.
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Udder physiology during the dry period
Drying-off management
Immunity in the mammary gland Active involution phase The active involution phase is critical to the development of IMIs and the reasons for the increased risk of infection can be divided into three categories, as follows: 1. Anatomical factors: ◗ Increased intramammary pressure caused by accumulation of mammary secretions, to the extent where milk may even leak out.
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◗ Anatomical changes in the teat, which becomes wider and shorter, enabling bacteria to enter more easily. ◗ The keratin plug begins to form. 2. Hygiene factors: ◗ Routine disinfection practised during milking in the lactation period ceases. ◗ The act of milking itself has the effect of flushing bacteria through the teat canal towards the exterior.
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UDDER PHYSIOLOGY DURING THE DRY PERIOD
3. Immune factors: ◗ Milk composition does not change in the first three days, so there are hardly any defence factors at all. ◗ Immune defence cells, such as polymorphonuclear leukocytes (PMN) and macrophages, which should remove any potential bacteria, are occupied phagocytosing milk debris, such as fat and casein, and epithelial cells.
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◗ Low lactoferrin levels in the first few days. ◗ Changes in diet and social group, where relationships with new animals have to be established, cause stress which, in turn, suppresses the immune system.
It is important that this phase is as short as possible to minimise the risk of mastitis. The shorter the active involution phase, the lower the risk of mastitis.
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Udder physiology during the dry period
Drying-o management
Mastitis risk factors during the dry period 1
2
3
The changes that occur during the involution phase increase the risk of IMI. 1. Milk accumulation: causes leaking and changes in the teat before the keratin plug has formed. 2. Udder hygiene is reduced. 3. Period of immunosuppression: cells are occupied phagocytosing epithelial cells and milk residues, which can even act as nutrients for bacteria. Stress caused by nutritional changes also encourages this state.
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UDDER PHYSIOLOGY DURING THE DRY PERIOD
Lactoferrin This protein is involved in the udder’s nonspecific defences during the dry period. It is produced in the lysosomes of the secretory cells and is also found in the granules of the PMNs. It acts as a mediator in the flow of PMNs, lymphocytes and macrophages, and therefore amplifies the immune response. It has a high binding affinity for iron, which is required for the survival of many mastitis-causing bacteria, such as coliforms (streptococci, for example, do not need much iron). As a result, it is an excellent bacteriostat in IMIs caused by bacteria such as coliforms and staphylococci.
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When citrate is present, lactoferrin becomes less effective, as citrate is also an iron chelator and so competes for this element. The molar ratio of citrate to lactoferrin determines the degree of coliform growth in vitro.
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The lower the citrate:lactoferrin molar ratio, the greater the inhibition of coliform growth.
Lactoferrin levels start to increase significantly from day 4 of the dry period.
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3
Risk of mammary infections
Drying-off management
Reduced intake
Negative energy balance
Immunosuppression
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Increased likelihood of IMI
Figure 10. Reduced feed intake during the dry period can be detrimental to the immune status of the cow.
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RISK OF MAMMARY INFECTIONS
Table 1. Factors that increase the risk of IMI at drying-off. Udder
Cow
Herd
Bacterial population Teat integrity Keratin plug Parity High milk production Drying-off method Duration of the dry period Environment Prevention Nutrition
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Udder cleanliness Hyperkeratosis Late formation Older cows Increased intramammary pressure ◗ Abrupt ◗ Gradual Short Poor on-farm hygiene Ineffective or nonexistent preventive measures Poor management, sudden changes
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Strategies to prevent new infections The biggest problem in the drying-off period is milk production, as the risk of infection is greater at higher levels of production. This factor is more obvious in abrupt drying-off, as milk retention is greater. Gradual drying-off involves reducing milk production and the volume of milk retained, and it is associated with less milk leakage by squirting or dripping, reduced IMIs at calving and, therefore, improved udder health. The disadvantage of this method is its management, which is complicated in practice. Many studies have been conducted to discover the best drying-off method, and results have varied: the first studies demonstrated that gradual drying-off reduces the amount of IMIs; other more
Drying-off management
recent studies have shown that cows dried off gradually give less milk. It has also been demonstrated that multiparous cows that are dried off gradually and have an IMI at drying-off, and primiparous cows that are dried off abruptly with milk leakage, are at greatest risk of infection at calving. It has recently been concluded that the occurrence of new infections is affected more by the presence of pathogens at drying-off than by milk production at drying-off.
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The existence of pathogens at drying-off affects the occurrence of IMIs more than the volume of milk produced.
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PREVENTION STRATEGIES
Advantages and disadvantages of drying-off methods Both types of drying-off have their advantages and disadvantages. Gradual drying-off: In general, milk leakage, and therefore the risk of IMI at calving, decreases with reduced production. Disadvantages: milking at alternate sessions increases the duration of the active involution phase and its associated risks. This method is normally linked to dietary changes, which continue through the drying-off period, potentially causing stress and hunger, and suppressing the immune system. Another great disadvantage is the difficulty of implementing this method on large farms.
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Abrupt drying-off: Easier management, as all the cows on the farm are milked with the same frequency. The disadvantage is that milk leakage by squirting or dripping can increase, raising the probability of infection at calving. This method of drying cows off increases intramammary pressure which is likely to cause more discomfort and pain.
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Despite the disadvantages of this method, abrupt drying-off is used on most dairy farms. In fact, 90Â % of herds that are milk recorded in the United States are dried off abruptly.
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Strategies to prevent new infections
Drying-off management
In conclusion, the ideal situation is thought to be to dry cows off when they are producing less than 21 kg of milk, thus preventing intramammary pressure from increasing and reducing milk leakage. This can be achieved with an abrupt drying-off, with a slight dietary change where possible. It would be very useful to use different techniques that would enable milk production to be reduced without causing stress to the animal.
Ideally, cows should be dried off when they are producing less than 21 kg of milk.
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Figure 1. Increased intramammary pressure can cause milk leakage with the associated risk of IMI.
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PREVENTION STRATEGIES
Dry cow therapy Intramammary therapy Dry cow therapy consists of administering an antibiotic through the teat canal using a nozzle. The aim is to eliminate existing infections and prevent any new ones from developing. The products used should reach high concentrations in the mammary parenchyma and be long-acting to prolong their effect.
Any antimicrobials used should reach high concentrations in the mammary parenchyma and be long-acting.
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This treatment (initially penicillin) was originally used to combat major contagious pathogens, such as Staphylococcus aureus and Streptococcus agalactiae. The spectrum was subsequently widened to include gram-negative bacteria, so amoxicillin and cephalosporins started to be used. Penethamate, cloxacillin, and cephalosporins are the products most commonly used today.
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Strategies to prevent new infections
Drying-off management
Careful administration of intramammary therapy
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Hygiene measures should be adopted when using an intramammary nozzle, such as only introducing the tip of the cannula to prevent damage to the internal mucosa of the teat cistern.
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PREVENTION STRATEGIES
Determining pathogen susceptibility is a factor that must be considered to achieve maximum treatment efficacy. Table 1. Spectrum of activity of the antibiotics commonly used to treat dry cows in the United Kingdom
(adapted from Bradley and Green, 2007).
Penicillins/penethamate Ampicillin Cloxacillin/nafcillin Cephalonium Cefquinome Dihydrostreptomycin Framycetin/neomycin
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Gram-positive bacteria
β-Lactamaseproducing S. aureus
Gram-negative bacteria
+++ ++ +++ ++ ++ + ++
+++ ++ ++ ++ ++
+ ++ ++ +++ +++
It is essential to understand the epidemiology of infections found on the farm in order to choose the most effective antimicrobial treatment.
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