Association of cow and quarter-level factors at drying-off with new intramammary infections during the dry period

University of Guelph, Guelph, Ont., Canada N1G 2W1.
Preventive Veterinary Medicine (Impact Factor: 2.17). 05/2004; 63(1-2):75-89. DOI: 10.1016/j.prevetmed.2004.01.012
Source: PubMed


Our objective was to describe cow and quarter-level factors associated with drying-off, and to evaluate their impacts on new intramammary infections (IMI) during the dry period. Data from 300 cows in five research herds were collected starting 2 weeks prior to scheduled drying-off. Variables of interest included daily milk production, teat-end integrity, formation of the teat-canal keratin plug, and quarter-milk bacteriological culture results. Overall, 11% of quarters developed new IMI in the dry period; this varied by herd, parity and time of the study. Most new IMI were caused by environmental streptococci and coliform organisms (34 and 30%, respectively). Quarters that had a cracked teat-end had higher odds of developing new infections than those without cracks (15 and 10%, respectively). Quarters that formed a keratin plug early in the dry period had a lower odds than those that did not close (10 and 14%, respectively). After 6 dry weeks, 23% of quarters were still open. The hazard of quarters closing if milk production on the day prior to drying-off was >21 kg 1.8-times less.

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    • " was only significantly higher in ud - der quarters with rough teat ends if corynebacteria were present simultaneously and in teats with extreme thick callosity rings around the orifice ( Zadoks et al . , 2001 ) . In a study investigating NIMI during the dry period , quarters with cracked teat ends before drying - off had 70% higher odds of NIMI ( Dingwell et al . , 2004 ) . The odds of isolation of a mastitis pathogen from a quarter milk sample increased with increasing teat - end callosity score of the corresponding teat ( de Pinho Manzi et al . , 2012 ) . However , cows with mild and moderate teat - end callosity had a decreased risk of SCC >199 , 000 cells / mL at the next milk recording compared wi"
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    ABSTRACT: Machine milking-induced alterations of teat tissue may impair local defense mechanisms and increase the risk of new intramammary infections. The objective of the current study was to assess the influence of short-term and long-term alterations of teat tissue and infectious status of the udder quarter on the risk of naturally occurring new intramammary infections, inflammatory responses, and mastitis. Short-term and long-term changes in teat condition of right udder quarters of 135 cows of a commercial dairy farm in Saxony-Anhalt, Germany, were recorded monthly for 10 mo using simple classification schemes. Quarter milk samples were collected from all examined quarters at each farm visit. Bacteriological culture results and somatic cell counts of quarter milk samples were used to determine new inflammatory responses (increase from ≤100,000 cells/mL to >100,000 cells/mL between 2 samples), new infections (detection of a pathogen from a quarter that was free of the same pathogen at the preceding sampling), and new mastitis (combination of new inflammatory response and new infection). Separate Poisson mixed models for new inflammatory responses, new infections, and new mastitis caused by specific pathogens or groups of pathogens (contagious, environmental, major, minor, or any) were used to estimate risk ratios and 95% confidence intervals. Data preparation and parameter estimation were performed using the open source statistical analysis software R. We observed no effect of any variable describing teat condition on the risk of new intramammary infections, inflammatory responses, or mastitis. Intramammary infections of the same udder quarter in the preceding month did not affect risk either. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.
    Journal of Dairy Science 12/2014; 98(2). DOI:10.3168/jds.2014-8446 · 2.57 Impact Factor
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    • "The formation of a teat-canal keratin plug prevents the penetration of bacteria and is therefore an important protective factor for the mammary gland (Cousins et al., 1980; Capuco et al., 1992). Lower milk production at drying-off is associated with rapid closure of the teat canal (Dingwell et al., 2004; Odensten et al., 2007a). "
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    ABSTRACT: A cow's risk of acquiring a new intramammary infection during the dry period increases with milk production at drying-off. A method commonly used to reduce milk production is a drastic reduction in feed supply in the days that precede drying-off. Milk production can also be reduced by inhibiting the lactogenic signal driven by prolactin (PRL). This study aimed to compare the effects of these 2 drying-off procedures on milk production, metabolism, and susceptibility to intramammary infection in cows. A total of 21 Holstein cows in late lactation were assigned to 1 of 3 treatments based on milk yield, somatic cell count, and parity. The cows were fed a lactation diet until drying-off (control), only dry hay during the last 5 d before drying-off (DH), or the same diet as the control cows but with twice-daily i.m. injections of 4 mg of quinagolide, a specific inhibitor of PRL release, from 5 d before drying-off until 13 d after (QN). On d 1 to 7 after the last milking, the cows were challenged by daily teat dipping in a solution containing Streptococcus agalactiae at 5 × 107 cfu/mL. Quinagolide induced a decrease in PRL concentration in blood on all the injection days. Blood PRL was also depressed in the hay-fed cows before drying-off. Both the QN and DH treatments induced a decrease in milk production, which at drying-off averaged 12.0, 10.0, and 21.7 kg/d for the QN, DH, and control cows, respectively. The DH treatment decreased blood concentration of glucose and increased blood concentrations of β-hydroxybutyrate and nonesterified fatty acids before drying-off. Somatic cell count at drying-off was greater in the milk of the QN cows than in that of the control cows but after drying-off was greater in the mammary secretions of the control cows than in those of the QN cows. The number of S. agalactiae colonies found in mammary secretions on d 8 and 14 after the last milking was lower for the QN cows than for the control cows. The percentage of S. agalactiae-infected quarters was also lower in the QN cows than in the control cows and on d 14 averaged 17.2, 33.7, and 57.5% in the QN, DH, and control cows, respectively. No differences between the DH and control groups were observed for either bacterial count or infection rate. In conclusion, this experiment shows that PRL-release inhibition could be an alternative for reducing milk production and improving resistance to intramammary infection at drying-off.
    Journal of Dairy Science 11/2014; 98(1). DOI:10.3168/jds.2014-8426 · 2.57 Impact Factor
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    • "Older cows had a higher risk of new infection during the dry period and of CM at calving supporting the findings by other researchers [10,14,16]. Age-related anatomical changes of the teat with negative effects on local resistance (e.g. increase in diameter of the teat canal, diminished function of the teat canal sphincter) and reduced general resistance with increasing age are possible reasons for this increased risk of infection [10,14,16]. Considering the cure rate during the dry period, it was surprising that older cows had a lower risk of having no bacterial cure (BC) than younger cows. "
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    ABSTRACT: Factors affecting bacteriological cure rates (BCR) and new intramammary infections (IMI) during the dry period as well as clinical mastitis (CM) during early lactation were investigated in 414 German Holstein dairy cows receiving dry cow therapy. Cows were treated with either benethamine benzylpenicillin (300,000 IU), penethamate hydriodide (100,000 IU), and framycetin sulphate (100 mg, n = 136), or cefquinome (150 mg, n = 135), or benzathine cloxacillin (1,280 mg, n = 143). Overall BCR, IMI, and CM at parturition were 86.4%, 20.7%, and 4.3%, respectively. The three antibiotic treatments differed only in BCR, with cloxacillin yielding better results than the others. Udder quarters from cows with > 4 lactations had a higher risk of IMI and CM at calving. Chronic changes in udder tissues were linked to a lower BCR and were associated with a higher risk of CM during early lactation. The risk of CM at calving was higher in udder quarters with unspecific or subclinical mastitis before drying off. In conclusion, with antibiotic dry cow therapy, age and health status of the udder appear to be major determinants of IMI and CM during the dry period and early lactation, while BCR was associated with the antibiotic type and udder tissue status.
    Journal of veterinary science (Suwŏn-si, Korea) 09/2011; 12(3):227-33. DOI:10.4142/jvs.2011.12.3.227 · 1.16 Impact Factor
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