Proportion Of Quarters Research Articles

Effect of 2 herbal intramammary products on milk quantity and quality compared with conventional and no dry cow therapy

Dry cow therapy, administered at the end of lactation, is aimed at eliminating current and preventing future intramammary (IMM) bacterial infections and typically involves intramammary administration of antibiotics. Certified organic dairies in the United States are restricted from using antibiotics and must consider an alternative therapy or no dry cow therapy. The current study compared 2 herbal products to conventional dry cow therapy and no treatment for a total of 5 treatments over 2 trials. Trial 1 was conducted over 3 yr on 1 research farm and trial 2 included 4 commercial farms plus the research herd over 2 yr. Treatments included (1) a conventional IMM antibiotic and internal teat sealant (penicillin-dihydrostreptomycin and bismuth subnitrate; CON); (2) an herbal IMM product purported to act as a teat sealant (Cinnatube, New AgriTech Enterprises, Locke, NY; CIN); (3) an herbal IMM product (Phyto-Mast, Bovinity Health LLC, Narvon, PA; P-M); (4) Phyto-Mast and Cinnatube (PC); or (5) no dry cow therapy (NT). Each treatment group was balanced by breed, lactation number, due date, herd, and year. However, the CON treatment was used only in the research herd because of the intent to avoid antibiotic usage on the other 4 farms. Comparisons among treatments included the difference between pre- and posttreatment 305-d mature equivalent milk production (trial 1), somatic cell score change from dry-off to freshening at the cow and quarter levels (trials 1 and 2), and milk microbiology change over the dry period (trial 2). We detected no significant differences among treatments for milk yield differences between the lactation following treatment and the lactation preceding treatment. Changes in somatic cell score from one lactation to the next also did not differ significantly among treatments in either trial. Cure rates were not significantly different among treatments; only 19.6% of all quarters were infected at dry off. The proportion of quarters with new infections at 3 to 5d postcalving did not significantly differ among treatments, except between CIN and NT. Percentages (least squares means ± standard error) of quarters with new infections were 24±21% for CON, 15±7% for CIN, 30±10% for P-M, 32±11% for PC, and 35±11% for NT. The efficacy of the herbal products was similar to that of conventional therapy, and the herbal products had no apparent adverse effects.

English

The aim of this study was to determine the effect of selenium concentration in early lactation on mammary gland health and histological characteristics of the udder. The experiment included 30 high-yielding Holstein-Friesian cows. Selenium concentrations in blood and milk serum, and the average somatic cell count in the first and sixth months of lactation were analyzed. After exclusion of the experimental cows from the herd, histological characteristics of the udder were examined (the degree of leukocyte infiltration and the number of granulomas in the parenchyma). The mean selenium concentration in the blood serum was 0.62±0.11 mmol/L and that in the milk serum was 0.12±0.07 mmol/L. Optimal blood levels of selenium were found in 19 cows and suboptimal levels in 11 cows. A significant negative correlation was observed between blood and milk selenium concentrations and somatic cell count in early and mid lactation. There was no relationship between blood selenium concentration, milk selenium concentration and the amount of milk produced. Selenium-deficient cows had a significantly higher milk somatic cell count in early and mid lactation and significantly lower levels of selenium in milk. Upon histological analysis, 120 samples of individual quarters of the udder were grouped according to the degree of leukocyte infiltration and number of granulomas. Results showed that an increase in the degree of leukocyte infiltration and number of granulomas leads to an increase in the proportion of quarters from selenium-deficient cows and a decline in the percentage of quarters from cows exhibiting normal blood selenium concentrations. Selenium has a significant impact on udder health. Changes caused by selenium deficiency occur due to marked inflammation process in the mammary gland.

Retail Real Estate Cycles as Markov Chains

Executive Summary. Commercial real estate markets across cities evolve with considerable risk with respect to variables such as rent levels and growth, occupancy levels and trends, capital market developments, and construction conditions. The complex patterns are more understandable with the help of the real estate cycle models reviewed here. Describing the future with a set of alternative cycle points and their anticipated probabilities is an application of a well-developed area of probability theory, Markov chain analysis. Numerical examples show how descriptions of cycle conditions in an initial period can be used to generate risk formatted descriptions of cycle conditions. The results are plausible descriptions of future risks. Standard Markov chain calculations allow the real estate cycle analyst to anticipate the proportion of quarters that a market will reside in each cycle point.

Transmission dynamics of intramammary infections with coagulase-negative staphylococci

A field trial was conducted on 2 US dairy herds to evaluate the transmission dynamics of coagulase-negative staphylococci (CNS) during the lactation period. Quarter milk cultures positive for CNS were classified as intramammary infection (IMI) or incidental isolation (transient colonization). The average proportion of quarters with CNS IMI was 0.114 in farm 1 and 0.09 in farm 2, and corresponding estimates for quarters with transient colonization of CNS were 0.122 and 0.088 throughout the 13-mo study period. Transmission parameters were obtained both for IMI caused by CNS and for CNS-positive quarters classified as the combination of transient colonization and IMI. Transmission between cows and between quarters in the same cow was assessed. The transmission parameters (β) for IMI caused by CNS were 0.0066 (farm 1) and 0.0111 (farm 2). Corresponding estimates of β when IMI and transient colonization of CNS were assessed jointly were 0.0256 (farm 1) and 0.0253 (farm 2). On farm 1, risk of transmission for CNS IMI between quarters in the same cow was 2 times greater than that between quarters from cow to cow. Transmission of CNS was considered contagious in one farm but no distinction between contagious and environmental transmission could be made in the other. We hypothesize that between-farm variation may be related to diversity between prevailing CNS species or by differences in management. In the current study, estimates of the basic reproduction number (R0) at the farm level for CNS IMI were 0.59 and 0.84 in farms 1 and 2, respectively. This shows that the transmission of CNS from IMI during the lactation period would to be too low to maintain the observed herd prevalence of CNS IMI. The R0 values for the combination of transient colonization and IMI by CNS were 1.13 and 1.17 in farms 1 and 2, respectively. This indicates potential for sustained endemic infection of CNS throughout lactation. However, prevailing CNS species may also differ between transient colonization and IMI. Therefore, not only CNS originating from IMI or incidental isolation events, but also CNS IMI occurring from the period outside the lactation pen are essential for maintenance of the observed herd prevalence of CNS IMI throughout lactation in this study. The effect of IMI originating outside the lactation pen was verified in simulations with reduced entry of infectious quarters to the lactation pens. Measures against CNS IMI would probably increase in efficiency if prevention of infection during the dry period and early lactation were further emphasized in herd health programs.

Heterogeneous and decreasing HIV prevalence among women seeking antenatal care in Kinshasa, Democratic Republic of Congo

We examined HIV prevalence trends over 4.5 years among women receiving antenatal care in Kinshasa, Democratic Republic of Congo, by geographic location, clinic management and urbanicity. Quarterly proportions and 95% confidence intervals (CIs) of pregnant women with HIV positive results were determined using aggregate service provision and uptake data from 22 maternity units that provided vertical HIV prevention services from October 2004 to March 2009. Assuming linearity, proportions were assessed for trend via the Cochran-Armitage test. Multivariable binomial regression was used to describe detailed prevalence trends. HIV testing was offered to 220,006 pregnant women; 210,348 (95.6%) agreed to be tested and 191,216 (90.9%) received their results. A total of 3999 women were found to be HIV positive, a prevalence of 1.90% (95% CI: 1.84-1.96%). The median quarterly proportion of women testing positive for HIV was 1.94% (range: 1.44-2.44%). Prevalence was heterogeneous in terms of maternity management, urbanicity and geographic location. Modeling suggested that the overall prevalence dropped from 2.04% (95% CI: 1.92-2.16%) to 1.77% (95% CI: 1.66-1.88%) over 4.5 years, a relative decrease of 13.2% (95% CI: 3.53-22.9%). Trend testing corroborated this decline (P < 0.01). The decreasing HIV prevalence among Kinshasa antenatal care seekers is robust and encouraging. The relatively low prevalence and the weak existing healthcare system require prevention of mother-to-child transmission interventions that strengthen maternal and child healthcare service delivery. Complacency would be unwarranted: assuming a uniform national crude birth rate of 50/1000 and 1.8% antenatal HIV prevalence, approximately 7000 pregnant HIV infected women in Kinshasa, and 60,000 nationwide, are in need of care and prevention services yearly.

Reproductive Performance, Udder Health, and Antibiotic Resistance in Mastitis Bacteria isolated from Norwegian Red cows in Conventional and Organic Farming

BackgroundThe objectives of this study were to investigate whether there were differences between Norwegian Red cows in conventional and organic farming with respect to reproductive performance, udder health, and antibiotic resistance in udder pathogens.MethodsTwenty-five conventional and 24 organic herds from south-east and middle Norway participated in the study. Herds were matched such that geographical location, herd size, and barn types were similar across the cohorts. All organic herds were certified as organic between 1997 and 2003. All herds were members of the Norwegian Dairy Herd Recording System. The herds were visited once during the study. The relationship between the outcomes and explanatory variables were assessed using mixed linear models.ResultsThere were less > 2nd parity cows in conventional farming. The conventional cows had higher milk yields and received more concentrates than organic cows. Although after adjustment for milk yield and parity, somatic cell count was lower in organic cows than conventional cows. There was a higher proportion of quarters that were dried off at the herd visit in organic herds. No differences in the interval to first AI, interval to last AI or calving interval was revealed between organic and conventional cows. There was no difference between conventional and organic cows in quarter samples positive for mastitis bacteria from the herd visit. Milk yield and parity were associated with the likelihood of at least one quarter positive for mastitis bacteria. There was few S. aureus isolates resistance to penicillin in both management systems. Penicillin resistance against Coagulase negative staphylococci isolated from subclinically infected quarters was 48.5% in conventional herds and 46.5% in organic herds.ConclusionThere were no large differences between reproductive performance and udder health between conventional and organic farming for Norwegian Red cows.

Incidence of intramammary infections during the dry period without or with antibiotic treatment in dairy cows – a quantitative analysis of published data

The study was aimed at summarising the literature that compares the incidence levels of spontaneously occurring intramammary infections (IMI) during the dry period, without versus with antibiotic dry cow treatment (DCT). A meta-analytic relative risk (RR) calculation was implemented when a priori relevant. Two main categories of comparison were used in the 36 selected papers. In the first category, the udder quarters were randomly allocated (at quarter or cow level) to an untreated or a treated group. Quarter incidence averaged 12.8% (weighted mean) in untreated quarters, and depending on the DCT used, from 6.6 to 8.0% in treated quarters. The meta-analytic RR of new IMI for untreated versus treated quarters varied from 1.54 to 1.94, depending on the DCT used. DCT was mainly found effective against IMI due to streptococci and coagulase-positive staphylococci. Based on only a few papers, the application of an internal teat sealer was associated to a quite similar (or possibly better) protection against IMI than DCT, but only in a subpopulation of particular (selected) cows. In the second category of studies, a selective dry cow or quarter antibiotic-treatment (selective DCT or DQT), according to cow or quarter selection criteria, was compared to blanket DCT. The meta-analytic RR of new IMI was 1.71 for selective DCT versus blanket DCT. Selective DQT seemed to be more at risk than selective DCT, but consisted of treating a much lower proportion of quarters. The summary-results provided by our meta-analysis should only be used with caution, due to possibly low external validity. More research seems to be relevant on the risk factors of new IMI during the dry period to make the outcomes of omission of DCT in selected cows more predictable under field conditions.

Heritability of Intramammary Infections at First Parturition and Relationships with Sire Transmitting Abilities for Somatic Cell Score, Udder Type Traits, Productive Life, and Protein Yield

The objective of this study was to determine the relationships among daughter intramammary infections at first parturition and sire transmitting abilities for somatic cell score, udder type traits, productive life, and protein yield. Quarter milk samples from 958 daughters (in eight Pennsylvania herds and one Nebraska herd) of 182 Holstein sires were collected within a few days of first calving and cultured to determine intramammary infection status. A total of 446 cows had intramammary infections in 835 quarters at first parturition. Incidence of intramammary infections at first parturition and the proportion of quarters infected per cow were regressed on age at first calving, days in milk at sample collection, herd-season of calving (a classification variable), and sire transmitting abilities taken one at a time. Linear effects, non-linear effects, and odds ratios were estimated for sire transmitting abilities. Separate, preplanned analyses were conducted on data from one herd that gave all heifers an intramammary antibiotic infusion in each quarter 30 d prior to the expected calving date. Separate analyses were also conducted on dependent variables that considered intramammary infections at first parturition from: all organisms, coagulase-negative staphylococci, coliform species, streptococci other than Streptococcus agalactiae, and the most common environmental organisms (coliform species and streptococci other than Streptococcus agalactiae). Daughters of sires that transmit the lowest somatic cell score had the fewest intramammary infections at first parturition. Daughters of sires that transmit longer productive life, shorter teats, and closely spaced front teats had fewer intramammary infections at first parturition. Selection for lower somatic cell score, longer productive life, shorter teats, or closely spaced front teats may reduce the incidence of intramammary infections at first parturition.

Prevalence of clinical mastitis in 38 Waikato dairy herds in early lactation

Aim. To determine the prevalence of clinical mastitis in spring-calving dairy herds in the Waikato Region of New Zealand and to identify factors associated with variation in the prevalence of clinical mastitis between herds. Method. A total of 799 quarters from 595 dairy cows from 38 dairy herds were diagnosed by herd owners as having clinical mastitis between 8 July and 21 August 1997. Quarters diagnosed with clinical mastitis were sampled for bacterial culture and somatic cell count, and the presence of clots in the milk and the presence of udder oedema were assessed by a technician or veterinarian. Results. Clinical mastitis was diagnosed in an average (± s.e.m.) of 9.9% (± 0.8%, range 0.9–21.4%) of calved cows within the herds. Bacteria were not cultured from an average of 12.4 % (± 2.0%, range 0.0-45.5%) of cows and 22.3% (± 2.4%, range 0.0–54.0%) of quarters diagnosed as having clinical mastitis. There were significant differences between herds in the proportion of cows diagnosed with mastitis and in the proportion of clinical mastitis cases from which bacteria were not cultured. A decreased prevalence of clinical mastitis (p < 0.001) was associated with an increased percentage of the herd treated with dry cow antibiotics. An increased prevalence of clinical mastitis (p < 0.0001) was associated with both an increased percentage of cows treated in the previous season with lactating cow antibiotics and an increased percentage of heifers in the herd. Herds that were fed supplements before or during lactation had a higher prevalence of clinical mastitis than herds that were not fed supplements (p < 0.001). An increased proportion of quarters diagnosed with clinical mastitis that did not culture bacteria was associated with an increased prevalence of clinical mastitis (p < 0.001). The proportion of quarters that the technician or veterinarian found with evidence of clinical mastitis (i.e. a somatic cell count > 500 000 cells/ml and the presence of either clots or udder oedema) within a herd was inversely related to the proportion of quarters within a herd from which no bacteria were isolated. Conclusion. There was a large variation in the prevalence of clinical mastitis and in the proportion of clinical quarters from which no bacteria were grown between herds. Management factors such as the use of dry cow therapy, feeding regimes and heifer replacement rates all affected the prevalence of clinical mastitis. Herd owners appear to differ in the sensitivity and specificity of their diagnosis of clinical mastitis, with bacteria not isolated from up to 50% of quarters diagnosed with clinical mastitis in some herds. Improvements in the specificity of herd owner diagnosis of clinical mastitis may reduce the use of antibiotics for mastitis during lactation and hence may reduce the risk of antibiotic contamination of milk supplied for human consumption.

Effect of Duration of Teat Cup Liner Closure Per Pulsation Cycle on Bovine Mastitis

Measurements of teat end expansion and contraction times from step changes in pressure suggest that teat ends require a minimal duration of liner closure for response. Effect of duration of liner closure per pulsation cycle on susceptibility of the udder to infection was tested. Four durations of liner closure (liner more than half closed) were applied: zero, .17, .34, and .51s per pulsation cycle. For the latter three treatments, duration of the liner more than half open was .66s per pulsation cycle, resulting in pulsation rates of 72.3, 60.0, and 51.3 pulsations per min. Four groups, each of 10 British Friesian cows, were in a 4-wk experiment. High bacterial exposure of all teats was ensured by dipping them before and after each milking in a suspension of Streptococcus agalactiae and Streptococcus dysgalactiae. Numbers of quarters becoming infected per treatment group were 20, 11, 4, and 5. This result represents both a significant inverse linear and quadratic relationship between proportion of quarters becoming infected and duration of liner closure. We conclude that a sufficient duration of liner closure, i.e., one-third of a second or more, per pulsation cycle contributes to reducing risk of new mammary gland infections.

The detection of mastitis in individual quarters using electrical conductivity or somatic cell concentration.

In this investigation electrical conductivity (EC) and somatic cell concentration (SCC) were compared in 3 herds for their ability to correctly identify the infection status of quarters. For EC, thresholds of 6.0 and 6.8 mS/cm were used and comparisons were made between quarters within each cow. The method of comparison between quarters was the same as that described by the manufacturers of the AHI Mastitis Detector. For SCC a threshold of 500 x 10(3) cells/ml was used. For both EC and SCC considerable variation was found between herds for sensitivity (the proportion of quarters infected with a major pathogen and detected as abnormal), and specificity (the proportion of quarters free from infection and detected as normal). The mean sensitivity and specificity of EC for the three herds was 49% and 79% respectively, whereas for SCC the means were 71% and 81% respectively. The variation in sensitivity and specificity of EC between herds was attributed to differences in the distribution of EC for quarters of similar infection status. It was concluded that these differences in herd EC precluded the use of pre-determined EC thresholds which were applicable for detecting mastitis in all herds.

Electrical detection of subclinical mastitis

Abstract Extract Sir,— The work of Linzel et al.(2) (3) suggested that a high proportion of quarters showing subclinical infection could be detected by measuring the maximum absolute electrical conductivity of their foremilk. Consequently, it seemed worthwhile to evaluate the performance of a simple electrical conductivity meter * , designed to be a rapid and reliable test for subclinical mastitis, against the more conventional tests.

Iodinated Diaminodiphenylsulphone in the Treatment of Bovine Mastitis During The Non-Lactating Period

In three separate field trials, the efficacy of an intramammary product containing iodinated diaminodiphenylsulphone (IDDS) was compared with that of 500 mg benzathine cloxacillin and to a combination of 1 200 000 i.u. benzathine penicillin G and 1•0 g dihydrostreptomycin. IDDS is equivalent to 1•0 g dapsone and all trials were concerned with the elimination of udder infection during the non-lactating period. The three products exhibited different clearance rates against Gram-positive udder pathogens. IDDS eliminated 81 to 85% of Streptococcus agalactiae quarter infections, benzathine cloxacillin successfully removed 81 to 94% of these infections whereas 73% quarters infected with these organisms were cured after drying-off treatment with the benzathine penicillin/dihydrostreptomycin product. Clearance rates against Staphylococcus aureus quarter infections ranged between 49 and 89% after treatment with the IDDS product, 69 to 84% following treatment with benzathine cloxallin, and 72% with the benzathine penicillin/dihydrostreptomycin product. Efficacy data for IDDS and benzathine cloxacillin from one of the trials were analysed. The proportion of quarters in which infection was eliminated and the clearance rates against Staph.aureus infection were higher when benzathine cloxacillin was used, the differences were approaching significance at the 5% level. Although variations between farms was greater with IDDS than with benzathine cloxacillin, differences were not statistically significant. Dapsone was distributed well throughout the udder of the dry cow. Residues of dapsone and iodine were not detected in the colostrum of cows treated at drying-off with the IDDS product; the composition of the colostrum was similar to that of untreated cows, and calves drinking colostrum and milk from IDDS-treated glands showed no undesirable side-effects.