Association of cow and quarter-level factors at drying-off with new intramammary infections during the dry period.
ABSTRACT 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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ABSTRACT: Abstract AIMS: The main aim was to investigate the efficacy of a novel internal teat sealant (ITS) formulation containing bismuth subnitrate and the antiseptic chlorhexidine, in adult cows (Trial A) and nulliparous heifers (Trial B), to reduce the incidence of new intramammary infection (IMI) between treatment and calving and reduce the prevalence of IMI within 6 days following calving. In Trial A dairy cows (n = 326) without history of clinical mastitis and with a maximum composite milk somatic cell count <200,000 cells/mL during the current lactation were enrolled from three spring-calving mainly pasture-based herds immediately following the final milking. In Trial B all heifers (n = 166) were enrolled from two herds approximately 3 weeks before the start of calving. Glands were randomly assigned to controls or treatment with ITS, and mammary secretion samples were taken from all glands prior to treatment, and on two occasions 0-4 and 3-6 days post-calving to determine the incidence of new IMI and the prevalence of IMI immediately post-calving. Additionally, cows in Trial A were monitored for cases of clinical mastitis (CM) in the non-lactating period and animals in both trials were monitored for cases of CM within 30 days of calving. The ITS reduced the estimated incidence of new IMI with both major and any pathogens compared to control glands in cows (6.2% vs. 14.2% and 14.7% vs. 32.8%, respectively) and in heifers (3.0% vs. 13.1% and 13.4% vs. 25.3%, respectively) (p < 0.001). The ITS reduced the estimated prevalence of a major or any pathogen compared to untreated controls at both 0-4 and 3-6 days post-calving, in both cows and heifers. Additionally, the ITS reduced the incidence of CM in the non-lactating period in cows (-1.0%, p = 0.01) and in the 30 days following calving in heifers (-2.0%, p = 0.06), and tended to reduce the estimated incidence of CM in cows post-calving (-1.7%, p = 0.10). The novel ITS reduced the incidence of new IMI, and the prevalence of IMI at calving in both adult cows and heifers, and reduced the incidence of CM in the non-lactating period of cows in the first 30 days after calving in heifers. The results of these trials demonstrate the efficacy of a novel ITS for the control of mastitis in likely-uninfected dairy cows over the non-lactating period and in heifers in late pregnancy.New Zealand veterinary journal 02/2014; · 1.06 Impact Factor
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ABSTRACT: The objective of the study was to record, by means of ultrasonographic examination, changes occurring in the udder of ewes during involution and to compare differences between progressive or abrupt udder drying-off. In group A ewes, udder drying-off took place progressively during a period of 22 d; ewes were milked twice daily for the last time on day(D) 0; then, they were hand-milked once daily for a week (D1-D7), which was followed by another week during which ewes were hand-milked once every 2 d (D9, D11, D13), followed by a third week during which ewes were hand-milked once every 3 d (D16, D19, D22). In group B ewes, the procedure took place abruptly; ewes were milked twice daily for the last time on D0 and no milking was carried out after that. B-mode and Doppler ultrasonographic examination of the udder of all ewes was performed throughout the drying-off procedure. Appropriate data management and analysis were performed. Progressive changes of the various parameters evaluated throughout the study period were significant in both groups (P<0·005). Gray-scale results of mammary parenchyma progressively decreased during the study and differed significantly between group A and group B (P=0·049). A temporary increase in cistern volume was evident after cessation of lactation, but differences were not significant between the two groups (P>0·3). Diameter of the external pudendal artery progressively decreased during the study and differed significantly between the two groups (P=0·037). Both resistance index and pulsatility index progressively increased throughout the study period in both groups; for both parameters, differences between the two groups were significant (P<0·0005). B-mode ultrasonographic examination indicated differences in remodelling of the extracellular matrix in relation to the procedure for udder drying-off. Volume of the gland cistern did not appear to be affected by the procedure for udder drying-off. Doppler ultrasonographic examination confirmed that blood flow during initiated involution was lower than during a progressive procedure for drying-off.Journal of Dairy Research 06/2014; · 1.34 Impact Factor
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ABSTRACT: Incidence of mastitis is highest in dairy cows and it is a leader of all diseases and the economic losses, in dairy farms. The objective of this study is to analyse the incidence of clinical mastitis using the lactation number, lactation month and season of calving. In this study, we used 3,779 lactation data and animal health records collected from 1990 to 2006 at the National Institute of Animal Science. Out of 3,779 cows, a total of 1,721 cows were reported with clinical mastitis, which was 46.3%. The frequency of mastitis increased from 36.9% from first lactation to 56.0% by the fifth lactation. As many as 766 cows (46.9%) showed a recurrence of mastitis after 14 days, apart for two or more and chronic mastitis that were recorded for 657 cows (20.3%). This came to a total of 3,010 cases that had clinical mastitis in the herd for sixteen years. The distribution of incidence of clinical mastitis was highest during the first month of lactation at 24.4%, and it reached to 43.4% by the third month. The incidence of mastitis was even higher for cows in first lactation, showing 28.6% in the first month, and 42.9 percent by third month of lactation. Cows calved during the summer and winter months showed higher rate of incidence with 59.9% and 57.9% within 30 days of lactation, respectively. It is urgently needed to establish a preventative management for heifer cows during their expected first lactation and the clinical specific dry-period management strategies that influence the rate of clinical mastitis during the next lactation. The aim of this study is to present information that might be useful to improve clinical mastitis prevention.Korean Journal of Veterinary Service. 01/2011; 34(4).