Rate of infection of milked and unmilked udders

Neave, F. K.; Oliver, J.; Dodd, F. H.; Higgs, T. M.

doi:10.1017/s0022029900018847

Cited by 18 publications

(10 citation statements)

References 12 publications

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“…Reducing feed intake to maintenance levels from 2-3 days before drying off through to 7 days after drying off is a current recommendation of the New Zealand mastitis management plan (Anonymous 2001a). This recommendation is presumably based on data showing that cows producing >9 l/cow/day at the end of lactation developed more new infections than cows producing less than this amount (Neave et al 1968), and that reducing feed intake reduced milk production in late lactation (Lacy-Hulbert et al 1999). Reduction in feed intake and intermittent milking have been hypothesised as inducing early involution of the mammary gland and hence shortening the period of high susceptibility to new IMI following the cessation of milking (Bushe and Oliver 1987).…”

Section: Dct= Dry-cow Therapymentioning

confidence: 99%

Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation

McDougall¹

2003

New Zealand Veterinary Journal

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Section: Dct= Dry-cow Therapymentioning

confidence: 99%

Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation

McDougall¹

2003

New Zealand Veterinary Journal

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“…(iii) Experiments in which milking was suspended for a period and then reintroduced showed that flushing of the teat duct to prevent the ingress of bacteria is an important factor in reducing the incidence of intramammary infection (35,145). There are also reports that strict fore milking reduces rates of udder infection (68).…”

Section: Penetration Of the Teat Duct By Pathogensmentioning

confidence: 99%

Reviews of the progress of Dairy Science: Mastitis control – progress and prospects

Bramley

Dodd

1984

Journal of Dairy Research

211

115

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Introduction Development of control methods Antibiotic therapy Hygiene Control schemes Milking machine research Mastitis awareness The value of current control methods Aetiology of mastitis Staphylococcus aureus Streptococcus agalactiae Streptococcus dysgalactiae Streptococcus uberis Coliforms Pseudomonas aeruginosa Mycoplasma bovis Corynebacteria General characteristics of bovine mastitis Stages in the infection process Exposure to pathogenic microorganisms CONTENTS PAGE 481 482 482 483 483 484 484 485 486 486 486 487 487 487 488 488 488 489 489 490 Penetration of the teat duct by pathogens Establishment of an intramammary infection Parasite factors Host factors Cellular and immune defence of the udder Nonspecific defence mechanisms Elimination of infections Culling Spontaneous recovery from infection Antibiotic therapy Dynamics of infection in dairy herds Effects of mastitis monitoring systems on awareness and control Conclusions References * Grant aided by the Agricultural and Food Research Council.

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“…Indeed, rates of new infection during the dry period exceed those of lactation, which may be due to the absence of the flushing out effect of regular milking (Neave et al 1968; Thomas etal. 1972).…”

mentioning

confidence: 99%

Susceptibility of the bovine udder to bacterial infection in the dry period

Cousins¹,

Higgs²,

Jackson³

et al. 1980

Journal of Dairy Research

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The teats of 18 cows were externally exposed to infection with mastitis organisms by dipping them daily for 1 or 2 weeks in a mixed suspension of Streptococcus dysgalactiae and Str. uberis at the start, the middle or the end of the dry period. The teat sinuses of quarters which remained uninfected after external exposure at the beginning or the middle of the dry period were then infused with the same strains of streptococci. Of the 9 quarters infected following external exposure 8 occurred in animals exposed at the start and one in the middle of the dry period. Thirty-six new infections occurred after infusion of bacteria into the teat sinuses of 38 quarters. In a further trial with 10 cows, Staphylococcus aureus and Str. zooepidemicus were inoculated into the distal 3 mm of the streak canals of 5 cows immediately after drying-off and into those of 5 cows which had been dry for 28 weeks. Animals were slaughtered 48 h later and infection determined by teat puncture. Five infections occurred in cows which were at the start of the dry period and only one in the cows dry for 28 weeks. It is suggested that these differences in the rates of new infection between the early dry period and a very extended dry period are due to differences in the ease with which bacteria can penetrate the teat canal. At the later stage bacterial growth through the teat canal appeared to be inhibited.The unmilked udder is particularly susceptible to infection in the 3 weeks following drying-off (Neave, Dodd & Henriques, 1950). Indeed, rates of new infection during the dry period exceed those of lactation, which may be due to the absence of the flushing out effect of regular milking (Neave et al. 1968; Thomas etal. 1972). However, this could not account for the large difference in the rate of new infection between the early part and the later part of the dry period. This difference may be due to the higher level of exposure to bacteria at the beginning of the dry period, i.e. bacteria remaining on the teat skin from the preceding lactation period. Alternatively, progressive changes in the composition of the udder secretion during the dry period (Wheelock et al. 1967;Smith, Wheelock & Dodd, 19676) may influence the establishment of infection after bacterial penetration of the streak canal. It is also possible that changes within the streak canal, such as the formation of a natural seal, may make bacterial penetration more difficult in later stages of the dry period. The aim of the experiments described in this paper was to investigate further the changes in susceptibility to new infection during the dry period. Two experiments were carried out; the first was designed to expose the udders of dairy cows to similar numbers of pathogenic bacteria either at the beginning, the middle or towards the end of the dry period and to measure the resulting numbers of new infections. The second

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Rate of infection of milked and unmilked udders

Cited by 18 publications

References 12 publications

Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation

Management factors associated with the incidence of clinical mastitis over the non-lactation period and bulk tank somatic cell count during the subsequent lactation

Reviews of the progress of Dairy Science: Mastitis control – progress and prospects

Susceptibility of the bovine udder to bacterial infection in the dry period

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