Defences of the bovine mammary gland against infection and prospects for their enhancement

-A practical protocol to study udder immune status in field conditions was planned with the aim to assess different non-specific immune parameters in milk samples from dairy heifers during the periparturient period. Five herds located in northern Italy were selected and overall 39 heifers were enrolled in the trial. Milk samples were taken at 7, 14, 21, 28, 45, 60, and 75 days after calving. The parameters assessed were N-acetyl-β-glucosaminidase (NAGase), lysozyme, respiratory burst (RB), somatic cell counts (SCC) and serum protein profile. SCC and NAGase were higher in the first sampling after calving, while lysozyme showed large variations during the observation period without a definite trend. The levels of RB observed in the first two weeks after calving, even if lower, were not statistically different from the values observed in samples taken over the following weeks. This study confirmed that the levels of immune components in milk are different from what is observed at blood level in the same cow. A significant decrease in RB in milk polymorphonuclear leukocytes (PMN) post-calving was not observed; milk PMN from healthy cows showed low RB levels, while the values from infected quarters were significantly higher. Significant differences between healthy and infected animals were also observed for milk NAG, lactoglobulin and albumin. These data suggest that udder immune response could be influenced both by the cow immune status and by external factors such as pathogens and management. Therefore, the reduction in immune defences, particularly in heifers, is not unavoidable and methods to boost PMN activity should be explored.heifers / periparturient period / blood milk / non-specific immunity

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“…therefore exposed to pathogens. This explains the scientific and practical interest in understanding mammary gland immune defences [3,29].…”

Section: Discussionmentioning

confidence: 97%

Comparison of blood and milk non-specific immune parameters in heifers after calving in relation to udder health

et al. 2005

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“…Shortening the DPL can result in reduced milk production at drying off because of an extended lactation. Therefore, concentrations of fat, casein, lactose and citrate that are high at dry-off and interfere with natural defense (Craven and Williams, 1985;Breau and Oliver, 1986;Hurley and Rejman, 1986) are reduced for SDP cows during this period. Ingesting milk fat, casein and cell debris after diapedesis by phagocytes decreases their phagocytic function and induces apoptosis .…”

Section: Altered Dry Periodsmentioning

confidence: 99%

Effects of continuous lactation and short dry periods on mammary function and animal health

Collier

Annen-Dawson

Pezeshki

2012

Animal

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The dry period is required to facilitate cell turnover in the bovine mammary gland in order to optimize milk yield in the next lactation. Traditionally, an 8-week dry period has been a standard management practice for dairy cows based on retrospective analyses of milk yields following various dry period lengths. However, as milk production per cow has increased, transitioning cows from the nonlactating state to peak milk yield has grown more problematic. This has prompted new studies on dry period requirements for dairy cows. These studies indicate a clear parity effect on dry period requirement. First parity animals require a 60-day dry period, whereas lactations following later parities demonstrate no negative impact with 30-day dry period or even eliminating the dry period when somatotropin (ST) is also used to maintain milk yields. Shortened dry periods in first parity animals were associated with reduced mammary cell turnover during the dry period and early lactation and increased numbers of senescent cells and reduced functionality of lactating alveolar mammary cells postpartum. Use of ST and increased milking frequency postpartum reduced the impact of shortened dry periods. The majority of new intramammary infections occur during the dry period and persist into the following lactation. There is therefore the possibility of altering mastitis incidence by modifying or eliminating the dry period in older parity animals. As the composition of mammary secretions including immunoglobulins may be reduced when the dry period is reduced or eliminated, there is the possibility that the immune status of cows during the peripartum period is influenced by the length of the dry period.

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“…Several researchers have reviewed the normal physiological processes of udder defense mechanisms [10,16,55,106]. After bacterial invasion, leukocytes in milk recognize pathogens, and innate immunity attempts to resolve this IMI immediately (Fig.…”

Section: An Acute Phase Of Udder Defense Mechanism After Intramammarymentioning

confidence: 99%

Hyperketonemia and the impairment of udder defense: a review

et al. 2000

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-The objective of this study was to review the possible relationships between hyperketonemia and the function of phagocytes with respect to the bovine udder defense mechanism. We hypothesize that an increased incidence of clinical mastitis in high-producing cows is caused by the impairment of the udder defense mechanism during hyperketonemia. First, we review the acute phase of udder defense mechanisms after intramammary infection. The physiological changes of cows in negative energy balance are subsequently discussed. Finally, possible relationships between udder defense and physiological changes during negative energy balance, especially hyperketonemia, are reviewed. The three stages of an acute phase of udder defense are: (1) immediately eliminating invading pathogens by phagocytes, (2) releasing inflammatory substances, especially chemoattractants, and (3) migration of polymorphonuclear leukocytes into the infected udder. Leukocytes from hyperketonemia subjects show a lower capacity of the phagocytic defense mechanism. In addition, the phagocytic and bactericidal capacities of neutrophils are reduced when these cells are acting in the presence of high concentrations of ketone bodies. Lower amounts of cytokine production after bacterial infection are observed in ketotic subjects. The chemotactic capacity of blood leukocytes is impaired in leukocytes obtained from ketotic cows. Lower numbers of blood leukocytes are observed in ketotic cows. In conclusion, the impairment of the udder defense mechanism in negative energy balance cows seems related to hyperketonemia. ketosis / negative energy balance / mastitis / udder defense mechanism / cow Résumé -Hypercétonémie et diminution des défenses mammaires : une synthèse. L'objectif de cette étude est de présenter des relations possibles entre l'hypercétonémie et la fonction des phagocytes pour ce qui est des mécanismes de défense de la mamelle. Notre hypothèse est qu'une Vet. Res. 31 (2000) 397-412 397

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Defences of the bovine mammary gland against infection and prospects for their enhancement

Cited by 141 publications

References 145 publications

Comparison of blood and milk non-specific immune parameters in heifers after calving in relation to udder health

Comparison of blood and milk non-specific immune parameters in heifers after calving in relation to udder health

Effects of continuous lactation and short dry periods on mammary function and animal health

Hyperketonemia and the impairment of udder defense: a review

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