Oral administration of antimicrobials increase antimicrobial resistance in E. coli from chicken--a systematic review.

Antimicrobials play an important role in animal and human health care. It was the aim of this systematic review to assess the effects of oral administration of antimicrobials on the development of antimicrobial resistance (AMR) in Escherichia coli (E. coli) from chickens. Moreover, the effects of the administration of more than one antimicrobial and of different dosages were studied. Literature was searched in November 2012 from the electronic databases ISI Web of Science, PubMed, Scopus and a national literature database (DIMDI) as well as the database ProQuest LLC. The search was updated in March 2014. Original studies describing a treatment (A) and a control group of either non-treatment (C) or initial value (0) and determining AMR in E. coli at different sample points (SP) were included. The literature search resulted in 35 full text articles on the topic, seven (20%) of which contained sufficient information on the administered antimicrobial and the impact of treatment on AMR. Most papers described the use of more than one antimicrobial, several dosages, controls (non-treatment or pre-treatment) and measured AMR at different SPs leading to a total of 227 SPs on the impact of the use of antimicrobials on AMR in chickens. 74% of the SPs (168/227) described a higher AMR-rate in E. coli from treated animals than from controls. After the administration of a single antimicrobial, AMR increased at 72% of the SPs. Administration of more than one antimicrobial increased AMR at 82% of the SPs. Higher dosages were associated with similar or higher AMR rates. The limited number of studies for each antimicrobial agent and the high variability in the resistance effect call for more well designed studies on the impact of oral administration on AMR development and spread.

Track way distance and cover as risk factors for lameness in Danish dairy cows.

This study investigates the effect of length and cover of track ways between barn and pasture on lameness in Danish dairy cows. We hypothesised that short track distances would be associated with a lower lameness probability of dairy cows compared to longer distances and that track ways with prepared cover (asphalt, gravel, slag, concrete, rubber) compared to no prepared cover (sand, soil and/or grass) would be associated with a lower lameness probability of dairy cows in grazing herds. In total, 2084 dairy cows from 36 herds, grazing their dairy cows during summer, were individually assessed for their lameness status. The cows were further clinically examined for claw conformation and hock integument. Information on breed and parity per cow and size per herd was extracted from a national data base. Track way distance ranged from 0 to 700 m and was categorised as (1) <165 m or (2) ≥165 m. Cover of track way was categorised as (1) prepared (asphalt, gravel, slag, concrete, and/or rubber), (2) partly prepared or (3) not prepared (soil, sand, grass) for the surface of the majority of tracks used. The effect of track way distance and cover was evaluated for their impact on lameness using logistic analysis with a multi-level model structure. The probability for lameness did not change with track distance but increased with no (odds 4.0 times higher) or only partly prepared (odds 3.8 times higher) cover compared to prepared cover. In conclusion, we found that having a cover on the track way was associated with decreased severe lameness in Danish dairy cows.

Oral antimicrobials increase antimicrobial resistance in porcine E. coli--a systematic review.

Administration of antimicrobials to livestock increases the risk of antimicrobial resistance (AMR) in commensal bacteria. Antimicrobials in pig production are usually administered per pen via feed which implies treatment of sick alongside with healthy animals. The objective of this systematic literature review was to investigate the effect of orally administered antimicrobials on AMR in Escherichia coli of swine. Studies published in peer reviewed journals were retrieved from the international online databases ISI Web of Knowledge, PubMed, Scopus and the national electronic literature data base of Deutsches Institut für Medizinische Dokumentation und Information. The studies were assessed using the eligibility criteria English or German language, access to full paper version, defined treatment and control group (initial value or non-treatment) as well as administration and resistance testing of the same antimicrobial class. In the qualitative synthesis, only studies were included presenting the summary measures odds ratio or prevalence of resistance, the category of the applied antimicrobial and the dosage. An effect of the antimicrobial on AMR in E. coli was evaluated as an "increase", "no effect" or "decrease" if the odds or alternatively the prevalence ratio were >1.0, 1.0 or <1.0, respectively. Eleven studies, describing 36 different trials, fulfilled the eligibility criteria and were finally assessed. An increase of AMR in E. coli was found in 10 out of 11 trials comparing AMR after with AMR prior to oral treatment and in 22 of the 25 trials comparing orally treated with untreated groups. Effects expressed as odds or prevalence ratios were highest for the use of aminoglycosides, quinolones and tetracycline. There was no clear association between the reported dosage and AMR towards tetracycline. Information on antimicrobial substance and dosage was missing in 4 and 5 of the 11 finally selected studies. The 36 identified trials were inhomogenous in usage and provision of information on sample size. Oral administration of antimicrobials increases the risk of AMR in E. coli from swine. There is however a lack of studies on the impact of dosage and longitudinal effects of treatment. The published studies have a number of issues concerning their scientific quality. More high quality research is needed to better address and quantifiy the effect of orally administered antimicrobials on AMR in swine.

Effect of grazing on the cow welfare of dairy herds evaluated by a multidimensional welfare index.

Structural development in the prime sector has led to increasing herd sizes and new barn systems, followed by less summer grazing for dairy cows in Denmark. Effects of grazing on single welfare measures in dairy cows - for example, the presence of integument alterations or mortality - have been studied under different conditions. However, the effect of grazing on welfare, conceptualised as the multidimensional physical and mental state of the animal, has not yet been studied in contemporary cubicle loose-housing systems. The aim of our study was to investigate, based on a Welfare Quality® inspired multidimensional dairy cow welfare assessment protocol, the within-herd effect of summer grazing compared with winter barn housing in Danish dairy herds with cubicle free-stall systems for the lactating cows. Our hypothesis was that cow welfare in dairy herds was better during summer grazing than during full-time winter housing. Furthermore, we expected improved welfare with an increase in daily summer grazing hours. In total, 41 herds have been visited once in the winter and once in the summer of 2010 to assess their welfare status with 17 different animal- and resource-based welfare measures. A panel of 20 experts on cattle welfare and husbandry evaluated the relative weight of the 17 welfare measures in a multidimensional assessment scheme. They estimated exact weights for a priori constituted severe compared with moderate scores of welfare impairment concerning each measure, as well as relevance of the measures in relation to each other. A welfare index (WI; possible range 0 to 5400) was calculated for each herd and season with a higher index indicating poorer welfare. The within-herd comparison of summer grazing v. winter housing considered all the 17 measures. The mean WI in summer was significantly lower (better) than in winter (mean 2926 v. 3330; paired t-test P = 0.0001) based on a better state of the integument, claw conformation and better access to water and food. Body condition and faeces consistence were worse in summer. Many daily grazing hours (range average above 3 to 9 h) turned out to be more beneficial than few daily grazing hours (range average above 9 to 21 h) for the welfare of the dairy herds. In conclusion, this study reports a positive within-herd effect of summer grazing on dairy cow welfare, where many daily grazing hours were more beneficial than few daily grazing hours.

Daily grazing time as a risk factor for alterations at the hock joint integument in dairy cows.

Structural changes lead to increasing sizes of dairy herds and a reduction in grazing use. Thus, cows spend more time in the barn and become more exposed to the barn environment. The cubicle surface can result in damages of the cows' hock joint integument. Pasture is generally seen as a beneficial environment for cows. We hypothesized that a higher number of daily grazing hours reduce the probability of hock joint alterations in dairy cows from large herds. In total, 3148 lactating cows from 36 grazing and 20 zero-grazing dairy herds, with an average herd size of 173 cows, were assessed individually on one randomly selected body side for alterations in hock integument (score 0 for no alterations or hairless areas <2 cm, 1 for at least one hairless area of ≥2 cm, 2 for lesion or swelling). The cows were further assessed for lameness and cleanliness. Information on breed, parity and days in milk per cow was extracted from a national database. Cubicle surface was evaluated for each herd. Daily grazing hours 30 days before herd visits were recorded by the stockmen and later categorized as follows: zero hours (zero-grazing), few hours (3 to 9) and many hours (>9 to 21). The effects of daily grazing hours and other potential cow and herd-level risk factors were evaluated for their impact on hock integument alterations using a logistic analysis with a multi-level model structure. The probability for hock integument alterations such as hair loss, lesions or swellings decreased with increasing amount of grazing hours (odds of 3 to 9 h 2.2 times and odds of >9 to 21 h 4.8 times lower than of zero-grazing). The probability for only lesions or swellings decreased with >9 to 21 grazing hours (odds 2.1 times) but not with 3 to 9 h (odds 1.0 times) compared with zero-grazing. Lameness, hard cubicle surface and Danish Holstein v. other breeds showed an increasing effect on the probability for integument alterations. Increase in days in milk only showed an increasing effect on the probability for lesions and swellings. We concluded that a long daily stay on pasture is most beneficial for the hock joint integument of a dairy cow.

The effect of grazing on cow mortality in Danish dairy herds.

The effect of summer grazing in large Danish dairy herds and certain management characteristics of grazing were studied for their impact on dairy cow mortality. Mortality data (from the Danish Cattle Database) from 391 Danish dairy herds (>100 cows) were combined with information from a questionnaire survey of grazing procedures on these herds in 2008. In all, 131 of the herds were identified as summer grazing and 260 as zero-grazing herds. The mortality was affected by an interaction of summer grazing and milking system. The risk of a cow dying was reduced to 46% in a grazing compared to a zero-grazing herd having automatic milking system. In traditional milking system, mortality was reduced to 75% in grazing compared to zero-grazing herds. Within the grazing herds, the risk of mortality decreased with increasing number of hours on pasture during the season. Free access between barn and pasture was associated with increased cow mortality.

Separate housing for one month after calving improves production and health in primiparous cows but not in multiparous cows.

The hypothesis was that dairy cows housed for 1 mo after calving in a separate group with herd mates would produce more milk and would be healthier than cows integrated in a group of all lactating cows immediately after calving. The experiment was conducted with 489 cows in 6 commercial loose-housing dairy herds where cows were randomly selected for treatment (separate housing) or control. Cows selected for treatment were housed for 1 mo after calving in a separate section, and controls were housed in the remaining section of the barn for lactating cows. Data were compared for milk yield, somatic cell count, medical treatments, reproductive performance, culling, mortality, and clinical observation of scores for body condition, leg and udder hygiene, lameness, hock lesions, other cutaneous lesions, vaginal discharge, and condition of the hair coat. The analysis of the effect of separate housing showed that primiparous cows produced more milk [approximately 230 kg of energy-corrected milk from 0 to 305 d in milk (DIM)], whereas multiparous and especially parity 3+ cows produced less milk (approximately 394 kg of energy-corrected milk from 0 to 305 DIM) during the lactation. Separate housing had no effect on mortality or reproductive efficiency. In primiparous cows, the number of medical treatments for ketosis was reduced by separate housing [hazard ratio 0.33, 95% confidence interval (CI): 0.13-0.83]. Clinical evaluations showed that separate housing decreased the scores for hock lesions in cows at 0 to 30 DIM (odds ratio 0.41, CI: 0.19-0.91), whereas the scoring of leg cleanliness showed more dirty legs in separated cows at 0 to 30 DIM (odds ratio 3.61, CI: 2.01-6.47) compared with cows integrated into the herd immediately. The body condition score in separated cows was reduced from 0 to 30 DIM (score reduced by 0.16, CI: 0.07-0.25) and from 31 to 60 DIM (score reduced by 0.13, CI: 0.04-0.23) compared with cows integrated immediately. We concluded that separate housing for 1 mo after calving increased milk yield in primiparous cows but not in multiparous cows, which produced less milk. The hypothesis about fewer health problems could only be confirmed with regard to fewer primiparous cows being treated for ketosis.

Substrates for the cell surface protein kinase in blood: a calf serum protein and its precursor in plasma.

A protein in calf serum with molecular mass of 125,000 is selectively phosphorylated by the surface kinase activity of intact tissue culture cells and erythrocytes. The protein, termed pp125, is phosphorylated at serine and threonine residues to a ratio of greater than 1 mol P/mol. The pp125 is an acidic protein (pI 4.4) which also serves as substrate for purified phosvitin/casein kinases but not for cyclic AMP-dependent protein kinases. About 80-fold purification of pp125 was achieved by ion exchange and affinity chromatography. Gel filtration under non-reducing conditions showed that pp125 is part of a complex (Mr 535,000). The pp125 obviously originates from a large plasma protein: the incubation of calf plasma with intact cells in the presence of [gamma-32P]ATP resulted in the labeling of a protein with Mr greater than 300,000 (pp greater than 300). The relationship between pp greater than 300 in plasma and pp125 in serum was demonstrated by cyanogen bromide peptide patterns, and the use of specific anti-serum raised against pp125. Furthermore, it was shown that pp125 is derived from pp greater than 300 during blood clotting.

Catalytic and molecular properties of highly purified phosvitin/casein kinase type II from human epithelial cells in culture (HeLa) and relation to ecto protein kinase.

Phosvitin/casein type II kinase was purified from HeLa cell extracts to homogeneity and characterized. The kinase prefers phosvitin over casein (Vmax phosvitin greater than Vmax casein; apparent Km 0.5 microM phosvitin and 3.3 microM casein) and utilizes as cosubstrate ATP (apparent Km 3-4 microM), GTP (apparent Km 4-5 microM) and other purine nucleoside triphosphates, including dATP and dGTP but not pyrimidine nucleoside triphosphates. Enzyme reaction is optimal at pH 6-8 and at 10-25 mM Mg2+.Mg2+ cannot be replaced by, but is antagonized by other divalent metal ions. The kinase is stimulated by polycations (spermine) and monovalent cations (Na+,K+), and is inhibited by fluoride, 2,3-diphosphoglycerate, and low levels of heparin (50% inhibition at 0.1 microgram/ml). The HeLa enzyme is composed of three subunits with Mr of approximately 43,000 (alpha), 38,000 (alpha'), and 28,000 (beta) forming alpha alpha'beta 2 and alpha'2 beta 2 structures with obvious sequence homology of alpha with alpha' but not with beta. Photoaffinity labeling with [alpha-32P]- and [gamma-32P]8-azido-ATP revealed high affinity binding sites on subunits alpha and alpha' but not on subunit beta. The kinase autophosphorylates subunit beta and, much weaker, subunits alpha and alpha'. Ecto protein kinase, detectable only by its enzyme activity but not yet as a protein (J. Biol. Chem. 257, 322-329), was characterized in cell-bound form and in released form, and the released form both with and without prior separation from phosvitin which was employed to induce the kinase release from intact HeLa cells (Proc. Natl. Acad. Sci. U.S.A. 80, 4021-4025). Ratios of phosvitin/casein phosphorylation (greater than 2) and of ATP/GTP utilization (1.5-2.1), inhibition by heparin (50% inhibition at 0.1 microgram/ml), and amino-acid side chains phosphorylated in phosvitin and casein (serine, threonine) are comparable for cell-bound and released form. These properties resemble those of type II kinase as does Mr of released ecto kinase (120-150,000). Consistently, a protein with Mr 125,000 in calf serum and a protein (possibly two) with Mr greater than 300,000 in calf plasma which are selectively phosphorylated by the ecto kinase are also substrates of the type II kinase. Thus, nearly all properties examined of the ecto kinase are characteristic for a type II kinase.

Protein kinase activities in mammalian blood fluid.

Two protein kinase activities, one specific for phosvitin and another specific for histone, were detected in serum and plasma of calf as well as of human blood after precipitation with ammonium sulfate (40%) and chromatography on DEAE-Sephacel. The enzymes were separated by chromatography on phosphocellulose. The histone kinase is not related to the cyclic AMP-dependent protein kinase; it may derive at least partly from damaged cells. The phosvitin kinase activity carries characteristics of the so called casein kinase type II similar to that present at the surface of cells including blood cells.

Substrate-effected release of surface-located protein kinase from intact cells.

Protein kinase activity that is independent of cAMP has been reported to exist on the surface of intact HeLa cells. Here we report that the protein kinase activity can be released by the use of casein or phosvitin within a short period of time. The discharge of the enzyme occurs from intact cells since (i) the cells do not release intracellular material and (ii) the cultures continue to grow within any morphological alteration. As shown with phosvitin, the release of protein kinase depends on substrate concentration, incubation time, and temperature. The degree of inducible release or surface protein kinase is inversely related to cell density. Four incubations with phosvitin (1 mg/ml) are sufficient to liberate most of the enzyme, thus greatly reducing the capacity of the cells to phosphorylate cellular substrates at the surface. Within approximately 24 hr after protein kinase removal, cultures have restored their surface protein kinase. Cultured cells of different origin (rat liver, mouse cerebellum, and human lung) exhibited phosvitin-induced protein kinase release from intact cells. The possible significance of these observations with respect to extracellular protein phosphorylation is discussed.