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The objective of this study was to determine whether birth order influences piglet survival because of reduced uptake of maternal antibodies by the piglets born later in large litters. Forty-five litters were serially allocated to one of 2 study groups. The crèche group consisted of 18 litters for which the 205 piglets were removed to a warm box to prevent suckling until 4 h after delivery of the first pig, and the control group of 27 litters for which 306 piglets were allowed to suckle from birth. The protein content of piglet blood and sow colostrum was determined with Brix refractometers. Parity, farrowing duration, liveborn litter size, litter size at 12 d, and piglet weight at birth and at 24 h and 12 d of age did not differ between the 2 treatment groups (L’objectif de la présente étude était de déterminer si l’ordre de naissance influence la survie des porcelets à cause de la réduction d’ingestion d’anticorps maternels par les porcelets nés plus tard dans les portées nombreuses. Quarante-cinq portées ont été réparties de manière successive à l’un des deux groupes d’étude. Le groupe crèche était constitué de 18 portées pour lesquelles les 205 porcelets ont été maintenus dans une boîte chauffée pour empêcher la tétée jusqu’à 4 h après la naissance du premier porcelet, et le groupe témoin de 27 portées pour lesquelles les 306 porcelets ont pu téter dès la naissance. Le contenu en protéine du sang des porcelets et du colostrum de la truie a été déterminé avec un réfractomètre Brix. La parité, la durée de la mise-bas, le nombre de porcelets nés vivants, la taille de la portée à 12 j, et le poids des porcelets à la naissance et à 24 h et 12 j d’âge n’étaient pas différents entre les deux groupes de traitement (

Mastitis is probably the most common and costly disease in modern dairy cow husbandry. The aim of the present paper was to report the results concerning udder health after implementation of a specific strategy using both field and laboratory methods. During the period June 2010-December 2011 a total of 674 dairy cows from four dairy farms were included in the investigation. Clinical mastitis was diagnosed by detection of signs of inflammation in the udder, while subclinical mastitis was diagnosed at the animal level by an increased Somatic Cell Count (SCC) using laboratory tests, and subsequently confirmed at quarter level by California Mastitis Test (CMT).Microbiological analysis of the milk samples was carried out by standard procedures using Gram staining, biochemical tests and automated identification system.The distribution of somatic cell counts on cow level (n=674) was:305 (45.3%) with SCC less than 100,000SCC/mL, 236 (35.0%) 100,001 - 350,000 SCC/mL, and 133 (18.7%) with more than 350,000SCC/mL. From a total of 1684 quarters tested by CMT, 644 quarters (38.2%) were positive and 1040 quarters (61.8%) were negative. In 60 out of 101 quarters that had a positive CMT result and no current treatment and that were sampled for bacteriology, bacteria could be isolated. Main bacteria identified, were coagulase - negative staphylococci (40.0%), Streptococcus agalactiae was present in 25.0%, Escherichia coli in 16.6%, Proteus spp. in 11.7% and Staphylococcus aureus in 6.7% of the bacteriological positive samples. After introducing specific mastitis-control measures, focusing on milking hygiene, dry-off treatment, and antibiotic treatment of both clinical and sub-clinical mastitis cases, the prevalence of subclinical mastitis was reduced from 38.2to 10.8%, while the incidence of clinical mastitis decreased from 21.0% to 4.9%.In conclusion, the implementation of a standard mastitis control plan based on a regular assessment of the somatic cell count can reduce the prevalence of clinical and sub-clinical mastitis in dairy herds.

Refereed/Peer-reviewed Gonadotropin-releasing hormone (GnRH) plays a vital role in regulating the reproductive system in animals, making it a potential target for controlling fertility. While GnRH-based technologies have been developed for use in animals, their widespread application has been limited. GnRH agonists and antagonists have been developed to regulate ovulation and control fertility in animals and, therefore, GnRH-based technologies may be enhanced by developing different drug delivery systems. The use of GnRH analogues for improving fertility in animals has traditionally been limited to injection formulations, which can be stressful for animals and raises consumer concerns. However, recent advancements in intravaginal delivery of GnRH analogues have the potential to improve their accessibility, acceptability, and effectiveness in animals. The development and commercialization of alternative intravaginal formulations of GnRH analogues, such as gels, tablets, suppositories, and implants, would be a significant advance in the field of animal reproductive technology. The aim of this review is to explore the latest information on GnRH vaginal delivery systems and their efficacy in achieving their targeted goals.

Sub-clinical mastitis (SCM) affects milk composition. In this study, we hypothesise that large-scale mining of milk composition features by pattern recognition models can identify the best predictors of SCM within the milk composition features. To this end, using data mining algorithms, we conducted a large-scale and longitudinal study to evaluate the ability of various milk production parameters as indicators of SCM. SCM is the most prevalent disease of dairy cattle, causing substantial economic loss for the dairy industry. Developing new techniques to diagnose SCM in its early stages improves herd health and is of great importance. Test-day Somatic Cell Count (SCC) is the most common indicator of SCM and the primary mastitis surveillance approach worldwide. However, test-day SCC fluctuates widely between days, causing major concerns for its reliability. Consequently, there would be great benefit to identifying additional efficient indicators from large-scale and longitudinal studies. With this intent, data was collected at every milking (twice per day) for a period of 2 months from a single farm using in-line electronic equipment (346 248 records in total). The following data were analysed: milk volume, protein concentration, lactose concentration, electrical conductivity (EC), milking time and peak flow. Three SCC cut-offs were used to estimate the prevalence of SCM: Australian > 250 000 cells/ml, European >= 200 000 cells/ml and New Zealand >= 150 000 cells/ml. At first, 10 different Attribute Weighting Algorithms (AWM) were applied to the data. In the absence of SCC, lactose concentration featured as the most important variable, followed by EC. For the first time, using attribute weighted modelling, we showed that the concentration of lactose in milk can be used as a strong indicator of SCM. The development of machine-learning expert systems using two or more milk variables (such as lactose concentration and EC) may produce a predictive pattern for early SCM detection. Refereed/Peer-reviewed

Increasing reports of multidrug-resistant bacterial infections in animals has created a need for novel antimicrobial agents that do not promote cross-resistance to critically important antimicrobial classes used in human medicine. In response to the recent emergence of antimicrobial resistance in several bovine mastitis pathogens, in vitro antimicrobial susceptibility was determined for four polyether ionophores (lasalocid, monensin, narasin and salinomycin) against Staphylococcus spp. and Streptococcus spp. isolated from clinical cases. In addition, erythrocyte haemolysis and WST-1 cell proliferation assays were used to assess in vitro mammalian cell cytotoxicity and biofilm susceptibility testing was performed using the minimum biofilm eradication concentration(MBEC™) biofilm assay. Lasalocid, monensin, narasin and salinomycin exhibited bacteriostatic antimicrobial activity against all pathogens tested, including methicillin-resistant staphylococci, with MIC90 values

Methicillin-resistant coagulase-negative staphylococci (MRCoNS) have recently emerged as a significant cause of bovine mastitis worldwide. Here we describe the isolation of MRCoNS from cases of bovine mastitis from a single dairy farm in Australia. Fourteen CoNS isolates were identified as MRCoNS on the basis of having an oxacillin MIC of ≥0.5 μg/mL. The isolates were speciated as S. chromogenes (n = 1) S. fleurettii (n = 1), S. haemolyticus (n = 2), S. sciuri (n = 5), S. simulans (n = 1) S. succinus (n = 2) and S. xylosus (n = 2). Five of the isolates (S. fleuretti, S. haemolyticus S. sciuri and two S. succinus) were mecA-positive. We also detected a previously described S. sciuri mecA homolog in four oxacillin-resistant S. sciuri isolates. The remainder of the putative MRCoNS did not contain any mecA-related resistance determinants in their genomes. Comparative genomic analysis of three previously published S. sciuri isolates, from humans, a squirrel and a cereal crop (rice), and a representative isolate from our study demonstrated clustering and a high degree of genetic homogeneity ( > 95%), suggesting S. sciuri has low host specificity. In conclusion, CoNS, in particular S. sciuri, may act as a reservoir for SCCmec elements that can easily be spread between different host species by direct cross-infection. Refereed/Peer-reviewed

Made available in DSpace on 2018-11-26T17:40:30Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-09-05 Australian Research Council (ARC) Neoculi Pty Ltd National Health and Medical Research Council of Australia (NHMRC) University of South Australia Sansom Institute of Health Research Micromyx LLC The spread of multidrug resistance among bacterial pathogens poses a serious threat to public health worldwide. Recent approaches towards combating antimicrobial resistance include repurposing old compounds with known safety and development pathways as new antibacterial classes with novel mechanisms of action. Here we show that an analog of the anticoccidial drug robenidine (4,6-bis(2-((E)-4-methylbenzylidene)hydrazinyl)pyrimidin-2-amine; NCL195) displays potent bactericidal activity against Streptococcus pneumoniae and Staphylococcus aureus by disrupting the cell membrane potential. NCL195 was less cytotoxic to mammalian cell lines than the parent compound, showed low metabolic degradation rates by human and mouse liver microsomes, and exhibited high plasma concentration and low plasma clearance rates in mice. NCL195 was bactericidal against Acinetobacter spp and Neisseria meningitidis and also demonstrated potent activity against A. baumannii, Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae and Enterobacter spp. in the presence of sub-inhibitory concentrations of ethylenediaminetetraacetic acid (EDTA) and polymyxin B. These findings demonstrate that NCL195 represents a new chemical lead for further medicinal chemistry and pharmaceutical development to enhance potency, solubility and selectivity against serious bacterial pathogens. Univ Adelaide, Sch Anim & Vet Sci, Australian Ctr Antimicrobial Resistance Ecol, Roseworthy, SA, Australia Univ Newcastle, Sch Environm & Life Sci, Chem, Callaghan, NSW, Australia Univ Adelaide, Sch Anim & Vet Sci, Roseworthy, SA, Australia Neoculi Pty Ltd, Burwood, Vic, Australia Univ South Australia, Sansom Inst Hlth Res, Sch Pharm & Med Sci, Ctr Pharmaceut Innovat & Dev, Adelaide, SA, Australia Univ South Australia, Sansom Inst Hlth Res, Sch Pharm & Med Sci, Adelaide, SA, Australia Monash Univ, Monash Inst Pharmaceut Sci, Ctr Drug Candidate Optimisat, Parkville, Vic, Australia Sao Paulo State Univ, Sch Pharmaceut Sci, Dept Drugs & Med, Sao Paulo, Brazil Fiona Stanley Hosp, Path West Lab Med WA, Dept Microbiol, Murdoch, WA, Australia Murdoch Univ, Sch Vet & Life Sci, Murdoch, WA, Australia Micromyx LLC, Kalamazoo, MI USA Univ Adelaide, Sch Biol Sci, Dept Mol & Cellular Biol, Adelaide, SA, Australia Univ Adelaide, Sch Biol Sci, Dept Mol & Cellular Biol, Res Ctr Infect Dis, Adelaide, SA, Australia Sao Paulo State Univ, Sch Pharmaceut Sci, Dept Drugs & Med, Sao Paulo, Brazil Australian Research Council (ARC): LP110200770 National Health and Medical Research Council of Australia (NHMRC): 565526 National Health and Medical Research Council of Australia (NHMRC): 627142

Sub-clinical bovine mastitis decreases milk quality and production. Moreover, sub-clinical mastitis leads to the use of antibiotics with consequent increased risk of the emergence of antibiotic-resistant bacteria. Therefore, early detection of infected cows is of great importance. The Somatic Cell Count (SCC) day-test used for mastitis surveillance, gives data that fluctuate widely between days, creating questions about its reliability and early prediction power. The recent identification of risk parameters of sub-clinical mastitis based on milking parameters by machine learning models is emerging as a promising new tool to enhance early prediction of mastitis occurrence. To develop the optimal approach for early sub-clinical mastitis prediction, we implemented 2 steps: (1) Finding the best statistical models to accurately link patterns of risk factors to sub-clinical mastitis, and (2) Extending this application from the farms tested to new farms (method generalization). Herein, we applied various machine learning-based prediction systems on a big milking dataset to uncover the best predictive models of sub-clinical mastitis. Data from 364,249 milking instances were collected by an electronic automated in-line monitoring system where milk volume, lactose concentration, electrical conductivity (EC), protein concentration, peak flow and milking time for each sample were measured. To provide a platform for the application of the models developed to other farms, the Z transformation approach was employed. Following this, various prediction systems [Deep Learning (DL), Naïve Bayes, Generalized Liner Model, Logistic Regression, Decision Tree, Gradient-Boosted Tree (GBT) and Random Forest] were applied to the non-transformed milking dataset and to a Z-standardized dataset. ROC (Receiver Operating Characteristics Curve), AUC (Area Under The Curve), and high accuracy demonstrated the high sensitivity of GBT and DL in detecting sub-clinical mastitis. GBT was the most accurate model (accuracy of 84.9%) in prediction of sub-clinical bovine mastitis. These data demonstrate how these models could be applied for prediction of sub-clinical mastitis in multiple bovine herds regardless of the size and sampling techniques. Refereed/Peer-reviewed

The aim of this study was to develop an in vitro release model for intramammary drug delivery system (IMDS) evaluation. This study was the first to establish an in vitro-in vivo correlation with investigation of an IMDS containing lasalocid. Three different methods including the standard United States Pharmacopeia dissolution method with apparatus 2, a modified United States Pharmacopeia method using a dialysis bag, or a specifically designed enhancer cell system, were assessed for the release study. Full cream milk and water were selected as the release media. In vivo evaluation was carried out by administering lasalocid IMDS into the udder of lactating Holstein dairy cows. Milk samples were collected and analyzed at selected time points after treatment. Dissolution data were fitted to various kinetic models. The results indicated that the release rate of lasalocid from IMDS was controlled by factors other than diffusion, which could include the sedimentation of lasalocid to the interface and the wetting of lasalocid particles by water at the interface of oil in the formulation and release media. The results obtained in vivo and in vitro were consistent. The in vitro assessment supports formulation design for early stage development and potentially for in vivo performance analysis. Refereed/Peer-reviewed

Developing a reliable mastitis challenge infection model is required to test new intramammary antimicrobial preparations, other novel bovine mastitis treatments, and study mastitis pathogenesis. Three treatment groups of Holstein Friesian cows in active lactation were administered two doses (104 and 106 cfu/quarter) on a single occasion with one of the three Streptococcus uberis strains (BFR6019, MFF1283 and SA002) suspended in 5 ml of sterile PBS, administered via intramammary inoculation immediately after milking. All quarters that were challenged with S. uberis strains MLF1283 and BFR6019 showed clinical signs of mastitis on day 1 and 2 after the challenge. Strain SA002 had a lower rate of inducing clinical mastitis which was detected later than day 3 after the challenge. We successfully developed a rapid and reliable model for inducing experimental S. uberis mastitis with 100% success rate in cows in active lactation. On the basis of the correlation results between strains, RAPD fingerprinting results, clinical findings, and a 100% success rate of mastitis induction for low and high doses S. uberis strains MLF1283 and BFR6019, strain virulence seems to be a more important effect than challenge dose in induction of clinical mastitis following experimental challenge.

Wen Wang,1 Yunmei Song,1 Kiro Petrovski,2 Patricia Eats,2 Darren J Trott,2 Hui San Wong,2 Stephen W Page,3 Jeanette Perry,2 Sanjay Garg11School of Pharmacy and Medical Science, University of South Australia, Adelaide, SA, Australia; 2School of Animal and Veterinary Sciences, University of Adelaide, Adelaide, SA, Australia; 3Luoda Pharma Pty Ltd, Caringbah, NSW, AustraliaBackground: Mastitis is a major disease of dairy cattle. Given the recent emergence of methicillin-resistant Staphylococcus aureus as a cause of bovine mastitis, new intramammary (IMA) treatments are urgently required. Lasalocid, a member of the polyether ionophore class of antimicrobial agents, has not been previously administered to cows by the IMA route and has favorable characteristics for development as a mastitis treatment. This study aimed to develop an IMA drug delivery system (IMDS) of lasalocid for the treatment of bovine mastitis.Methods: Minimum inhibitory concentrations (MICs) were determined applying the procedures recommended by the Clinical and Laboratory Standards Institute. Solid dispersions (SDs) of lasalocid were prepared and characterized using differential scanning calorimetry and Fourier transform infrared spectroscopy. IMDSs containing lasalocid of micronized, nano-sized, or as SD form were tested for their IMA safety in cows. Therapeutic efficacy of lasalocid IMDSs was tested in a bovine model involving experimental IMA challenge with the mastitis pathogen Streptococcus uberis.Results: Lasalocid demonstrated antimicrobial activity against the major Gram-positive mastitis pathogens including S. aureus (MIC range 0.5–8µg/mL). The solubility test confirmed limited, ion-strength-dependent water solubility of lasalocid. A kinetic solubility study showed that SDs effectively enhanced water solubility of lasalocid (21–35-fold). Polyvinylpyrrolidone (PVP)-lasalocid SD caused minimum mammary irritation in treated cows and exhibited faster distribution in milk than either nano or microsized lasalocid. IMDSs with PVP-lasalocid SD provided effective treatment with a higher mastitis clinical and microbiological cure rate (66.7%) compared to cloxacillin (62.5%).Conclusion: Lasalocid SD IMDS provided high cure rates and effectiveness in treating bovine mastitis with acceptable safety in treated cows.Keywords: ionophore, methicillin-resistant Staphylococcus aureus, solid dispersion, intramammary drug delivery system, superbugs