Faecal egg counts in Australian pasture-based dairy herds.

In Australian pastoral dairy systems, a variety of 'routine' anthelmintic programs are used in lactating cows varying from nil anthelmintic use to bi-annual application. Anthelmintic resistance has been repeatedly diagnosed on dairy farms and studies have indicated variable milk production benefits from anthelmintics internationally. We aimed to identify the predominant gastrointestinal parasites in recently calved dairy cows in south-west Victoria and examined the relationship between individual faecal egg counts (FEC) and other cow and management factors such as body condition score, age, and historical anthelmintic use. This study included 18 pasture-based dairy farms in south-west Victoria. FECs were measured in recently calved primiparous and multiparous cows. Individual FEC tests with a minimum detectable FEC of 2.5 eggs per gram of faeces (epg) and group larval cultures were completed. Farm management data and cow information was recorded for data analysis with the Jamovi statistical package. Overall, 35% of all cows had FEC ≥ 2.5 epg (26% of multiparous and 45% of primiparous). Ostertagi ostertagi was the predominant gastrointestinal nematode in all cohorts. Cooperia pectinata or C. punctata were also present in mixed infestations alongside C. oncophora. Multiparous cows in low body condition score post calving (<4) were more likely to have a FEC of >5 epg. Faecal egg counts at a minimum detectable FEC of 2.5 epg are effective indicators of parasitism in recently calved primiparous and poorly conditioned multiparous dairy cows. Increasing the test sensitivity (minimum detectable count) of FECs from 10 epg to 2.5 epg resulted in increasing the overall positive FEC rate from 15% to 35%. Further investigation of sensitive FECs and their relevance to production along with the timing and value of anthelmintic use in dairy cattle is warranted.

Customized modified therapies for ovarian cyst and persistent follicle followed with TAI in early postpartum dairy cows.

Background: Postpartum ovarian dysfunction [ovarian cyst (OC) and persistent follicle (PF)] has been an important issue. Finding effective hormonal treatments to improve reproductive performance in dairy cows has become a necessity. Aim: Improve reproductive performance and ovarian activity in postpartum cows with specific customized treatment for OC and PFs. Methods: The study included 48 cows at 14 days P.P, which received two dosages of 500 µg IM cloprostenol, 14 days apart as presynchronization protocol. Ultrasound ovarian scans 14 days after the last injection for 4 weeks. The cows were divided into three groups according to ovarian status: OC (n = 14), PF (n = 12), and NE (n = 22). In the OC group, received 500 µg IM cloprostenol and 100 µg IM cystoriline, a second dose of cloprostenol 14 days later and a second dose of cystoriline 36 hours later, and AI after 24 hours (GnRH+ PG/PG/GnRH). In the PF group, was fitted with progesterone-releasing intravaginal device (PRID) for 9 days; the same day, they received 100 µg cystoreline then 500 µg cloprostenol 7 days later, after PRID removal AI 56 hours later (PRID + GnRH/PG). In the NE group, artificial insemination was implemented until 28 days depending on estrus detection. Results: The ovarian activity was greatly affected by the customized treatments, leading to enhanced follicular and luteal activity, particularly after the PGF2α injection. The OC and PF groups showed substantial estrus responses of 71.43% and 75.02%, respectively, during AI time. While the NE group had an ovulation rate of 54.5% and a pregnancy rate of 31.8%, the treatment groups showed marked improvements in reproductive performance. The ovulation rates in the OC and PF groups were 71.43% and 75% and the pregnancy rates at the 1st artificial insemination were 64.28% and 66.7%. Conclusion: Improving reproductive performance and minimizing the time to first service are possible advantages of early case-specific treatment for postpartum cows with OC and PFs.

Biomarkers of gastrointestinal nematodes in beef cattle raised in a tropical area.

Biomarkers are specific molecular, histological, or physiological characteristics of normal or pathogenic biological processes and are promising in the diagnosis of gastrointestinal nematodes (GINs). Although some biomarkers have been validated for infection by Ostertagia sp. in cattle raised in temperate regions, there is a lack of information for tropical regions. The aim of this project was to assess potential biomarkers and validate the most promising. In the first study, 36 bovines (Nelore breed) naturally infected by GINs were distributed into two groups: infected (not treated with anthelmintic) and treated (treated with fenbendazole on days 0, 7, 14, 21, 28, 42, and 56). The variables of interest were live weight, fecal egg count, hemogram, serum biochemical markers, phosphorus, gastrin, and pepsinogen. In the second step, pepsinogen was assessed in cattle of the Nelore breed distributed among three groups: infected (not treated with anthelmintic), MOX (treated with moxidectin), and IVM + BZD (treated with ivermectin + albendazole). In the first study, no difference between groups was found for weight, albumin, hematocrit (corpuscular volume [CV]), erythrocytes, or hemoglobin. Negative correlations were found between pepsinogen and both CV and albumin, and albumin was negatively correlated with the percentage of Haemonchus sp. in the fecal culture. Among the biomarkers, only pepsinogen differentiated treated and infected (beginning with the 28th day of the study). In the second study, a reduction in pepsinogen was found after anthelmintic treatment. Therefore, pepsinogen is a promising biomarker of worms in cattle naturally infected by the genera Haemonchus and Cooperia in tropical areas.

Evaluation of antimicrobial and non-steroidal anti-inflammatory treatments for BRD on health and welfare in fattening bulls: a cross-sectional study.

Our study aimed to evaluate the effect of different treatments for BRD on health and welfare in fattening bulls. A total of 264 bulls were enrolled. Welfare was assessed on day 2 (T0) and day 15 (T1) after arrival. A decrease in the welfare level was observed from T0 to T1. All bulls were inspected clinically at T0 and T1 revealing an increase of skin lesions and lameness in T1. In both periods, a high incidence of respiratory disease was observed. A prevalence of 79.55% and 95.45% of Mycoplasma bovis using RT-PCR and culture at T0 and T1 respectively was observed. Blood samples were collected for haematology at T0 and T1. At T0, 36 animals were individually treated for BRD with an antimicrobial (IT), 54 received a metaphylactic treatment with tulathromycin (M), 150 received a metaphylactic treatment with tulathromycin plus a second antimicrobial (M + IT) whereas 24 were considered healthy and therefore not treated (NT). Additionally, 128 were treated with a non-steroid anti-inflammatory (NSAID). Neutrophils of M + IT were significantly higher than groups NT and M and the lymphocytes of M + IT were significantly lower than that of IT. White blood cells, neutrophils and N/L ratio of animals treated with an NSAID was significantly higher than that not treated. Lung inspection of 172 bulls at the abattoir indicated that 92.43% presented at least one lung lesion. A statistically significant effect of the NSAID treatment on the lung lesions was observed. Our findings indicate that BRD was a major welfare and health concern and evidence the difficulties of antimicrobial treatment of M. bovis.

Comparison between intrauterine application of an antibiotic and an herbal product to treat clinical endometritis in dairy cattle - A randomized multicentre field study.

Uterine diseases are main indications for antibiotic use in dairy cows. To test a non-antibiotic treatment option, we compared the effect of an intrauterine cephapirin (Metricure®; cefapirin benzathin 500 mg per dosis; CEPH) with an intrauterine applied herbal product (25 ml of EucaComp® PlantaVet containing alcoholic extracts of Calendula officinalis L., Mellissa officinalis L., Origanum majorana L. and Eucalyptus globulus Labill. (EUC)) on the clinical cure of endometritis. Examinations of 816 cows between 21 and 35 days after calving were performed and cases of clinical endometritis (n = 169) were included. Diagnosis based on a scoring system for vaginal discharge. Study animals were randomly assigned to one of two treatment groups and treated immediately. After excluding animals with incomplete datasets, 136 cows (EUC: n = 61; CEPH: n = 75) remained for the final analysis. In total, 64% (EUC: 61%, CEPH: 67%) of analysed endometritis cases were considered as clinically cured 14 ± 2 days after the first treatment, 15% stayed uncured after the application of a maximum of two consecutive treatments, leading to an overall clinical cure rate of 85% (EUC: 82%, CEPH: 88%). No statistically difference in clinical cure rates could be observed between both treatment groups nor 14 ± 2 days after the first treatment (p = 0.956) neither regarding the overall cure rate (p = 0.923). In conclusion, the clinical cure of dairy cows' endometritis after the intrauterine application of the herbal product was non-inferior to the intrauterine application of the antibiotic cephapirin. These results could contribute to reduce the antimicrobial use in the daily veterinary routine treatment of endometritis.

Supplementation of rumen-protected lysine during the close-up period improves vaginal discharge clearance in Holstein dairy cows.

We aimed to evaluate the effects of rumen-protected lysine (RPL) supplementation during the close-up period on uterine involution and the resumption of ovarian function in dairy cows. Fifty-two multiparous Holstein cows were categorized based on parity and expected calving date and randomly assigned to the RPL or control (CON) groups. The RPL group received 80 g of RPL daily from day 21 before the expected calving date until parturition. Blood samples were obtained twice weekly from pre-supplementation to 6 weeks postpartum. The onset of luteal activity postpartum was determined via ultrasonography twice weekly for up to 6 weeks postpartum. Uterine involution was tracked at 3 and 5 weeks postpartum through the vaginal discharge score, percentage of polymorphonuclear cells (PMN) in endometrial cytology samples, presence of intrauterine fluid, and gravid horn diameter via ultrasonography. Before supplementation, the RPL group showed amino acid imbalance, which was improved by RPL supplementation. There were no significant differences in the onset of luteal activity, percentage of PMN, intrauterine fluid, or the diameter of the uterine horn between the two groups. The vaginal discharge score in the RPL group decreased from 3 to 5 weeks postpartum, whereas that in the CON groups did not decrease. The number of cows with clinical endometritis was lower in the RPL group. Overall, RPL supplementation during the close-up period enhanced vaginal discharge clearance, potentially averting clinical endometritis, but did not affect the first ovulation in dairy cows.

Pharmacokinetic/pharmacodynamic evaluation of gamithromycin against rabbit pasteurellosis.

BACKGROUND: Gamithromycin is an effective therapy for bovine and swine respiratory diseases but not utilized for rabbits. Given its potent activity against respiratory pathogens, we sought to determine the pharmacokinetic profiles, antimicrobial activity and target pharmacokinetic/pharmacodynamic (PK/PD) exposures associated with therapeutic effect of gamithromycin against Pasteurella multocida in rabbits. RESULTS: Gamithromycin showed favorable PK properties in rabbits, including high subcutaneous bioavailability (86.7 ± 10.7%) and low plasma protein binding (18.5-31.9%). PK analysis identified a mean plasma peak concentration (Cmax) of 1.64 ± 0.86 mg/L and terminal half-life (T1/2) of 31.5 ± 5.74 h after subcutaneous injection. For P. multocida, short post-antibiotic effects (PAE) (1.1-5.3 h) and post-antibiotic sub-inhibitory concentration effects (PA-SME) (6.6-9.1 h) were observed after exposure to gamithromycin at 1 to 4× minimal inhibitory concentration (MIC). Gamithromycin demonstrated concentration-dependent bactericidal activity and the PK/PD index area under the concentration-time curve over 24 h (AUC24h)/MIC correlated well with efficacy (R2 > 0.99). The plasma AUC24h/MIC ratios of gamithromycin associated with the bacteriostatic, bactericidal and bacterial eradication against P. multocida were 15.4, 24.9 and 27.8 h in rabbits, respectively. CONCLUSIONS: Subcutaneous administration of 6 mg/kg gamithromycin reached therapeutic concentrations in rabbit plasma against P. multocida. The PK/PD ratios determined herein in combination with ex vivo activity and favorable rabbit PK indicate that gamithromycin may be used for the treatment of rabbit pasteurellosis.

Impact of Limosilactobacillus fermentum probiotic treatment on gut microbiota composition in sahiwal calves with rotavirus diarrhea: A 16S metagenomic analysis study".

BACKGROUND: Diarrhea poses a major threat to bovine calves leading to mortality and economic losses. Among the causes of calf diarrhea, bovine rotavirus is a major etiological agent and may result in dysbiosis of gut microbiota. The current study was designed to investigate the effect of probiotic Limosilactobacillus fermentum (Accession No.OR504458) on the microbial composition of rotavirus-infected calves using 16S metagenomic analysis technique. Screening of rotavirus infection in calves below one month of age was done through clinical signs and Reverse Transcriptase PCR. The healthy calves (n = 10) were taken as control while the infected calves (n = 10) before treatment was designated as diarrheal group were treated with Probiotic for 5 days. All the calves were screened for the presence of rotavirus infection on each day and fecal scoring was done to assess the fecal consistency. Infected calves after treatment were designated as recovered group. Fecal samples from healthy, recovered and diarrheal (infected calves before sampling) were processed for DNA extraction while four samples from each group were processed for 16S metagenomic analysis using Illumina sequencing technique and analyzed via QIIME 2. RESULTS: The results show that Firmicutes were more abundant in the healthy and recovered group than in the diarrheal group. At the same time Proteobacteria was higher in abundance in the diarrheal group. Order Oscillospirales dominated healthy and recovered calves and Enterobacterials dominated the diarrheal group. Alpha diversity indices show that diversity indices based on richness were higher in the healthy group and lower in the diarrheal group while a mixed pattern of clustering between diarrheal and recovered groups samples in PCA plots based on beta diversity indices was observed. CONCLUSION: It is concluded that probiotic Limosilactobacillus Fermentum N-30 ameliorate the dysbiosis caused by rotavirus diarrhea and may be used to prevent diarrhea in pre-weaned calves after further exploration.

Changes in bacterial community composition in the uterus of Holstein cow with endometritis before and after treatment with oxytetracycline.

It is important to study the bacteria that cause endometritis to identify effective therapeutic drugs for dairy cows. In this study, 20% oxytetracycline was used to treat Holstein cows (n = 6) with severe endometritis. Additional 10 Holstein cows (5 for healthy cows, 5 for cows with mild endometritis) were also selected. At the same time, changes in bacterial communities were monitored by high-throughput sequencing. The results show that Escherichia coli, Staphylococcus aureus and other common pathogenic bacteria could be detected by traditional methods in cows both with and without endometritis. However, 16S sequencing results show that changes in the abundance of these bacteria were not significant. Endometritis is often caused by mixed infections in the uterus. Oxytetracycline did not completely remove existing bacteria. However, oxytetracycline could effectively inhibit endometritis and had a significant inhibitory effect on the genera Bacteroides, Trueperella, Peptoniphilus, Parvimonas, Porphyromonas, and Fusobacterium but had no significant inhibitory effect on the bacterial genera Marinospirillum, Erysipelothrix, and Enteractinococcus. During oxytetracycline treatment, the cell motility, endocrine system, exogenous system, glycan biosynthesis and metabolism, lipid metabolism, metabolism of terpenoids, polyketides, cofactors and vitamins, signal transduction, and transport and catabolism pathways were affected.

Randomized comparison between a forced air system and warm water bath for resuscitation of neonatal hypothermic calves with or without oral administration of caffeine.

BACKGROUND: Hypothermia is a cause of neonatal calf death in cold climates. Practical and effective rewarming methods are important for bovine health within affected regions. HYPOTHESIS/OBJECTIVES: To compare the rewarming rate and blood analytes (glucose, lactate, and cortisol) of calves resuscitated with forced air with warm water bath, with or without oral administration of caffeine. ANIMALS: Twenty healthy neonatal Holstein bull calves. METHODS: In this randomized, prospective study, calves born healthy and without history of dystocia were cooled to 32°C rectal temperature then thermally resuscitated using either forced air rewarming or warm water bath (40°C) with or without oral administration of caffeine. Rectal temperatures were used to quantify recovery rate. Measurements of glucose, lactate, and cortisol were recorded for every 2°C change in rectal temperature. RESULTS: Rectal temperature decline (0.03°C per minute) and total cooling time (191.0 ± 33.3 minutes) did not significantly differ among treatment groups. Calves were successfully resuscitated to 38°C by either method. Time required to euthermia using warm water was significantly faster (0.1°C per minute; 64.3 ± 17.8 minute; P < .05) than forced air (0.05°C per minute; 123.1 ± 20.0 minutes). Caffeine had no significant effect on resuscitation rate (P = .14; 95% CI, -0.002 to 0.024) in either treatment; however, caffeine was associated with reduced time to euthermia by 8.3 and 10.8 minutes, respectively. Changes in metabolic variables (glucose, lactate, and cortisol), were inversely related to rectal temperature with no statistical significance among rewarming methods. CONCLUSIONS AND CLINICAL IMPORTANCE: Although warm water submersion is faster, forced air rewarming is an effective alternative for restoration of euthermia.

Impacts of intake of trichothecenes (Fusarium sporotrichioides) for dairy calves: Effects on animal growth, oxidative and inflammatory response.

The objective of the present study was to evaluate the impacts of trichothecenes (Fusarium sporotrichioides) for dairy calves on animal growth, oxidative and inflammatory responses in the presence or absence of essential oils. Twelve calves weaned at 70 days of age were divided into 2 groups: T-C (control) and T-EO (essential oils - oregano, thyme, basil and rosemary) in the period of 40 days consuming ration contaminated by trichothecenes (500 ppb). The animals in the T-EO group received a mixture of EOs via feed at a dosage of 0.75 mL per/kg of feed. Blood collections were performed on days 1, 20 and 40 for hematological and biochemical analyses; the fecal score was performed every 2 days on a scale of 1-5 and clinical examinations were performed 3 times during the experiment period. The animals were weighed at the beginning and at the end of the experiment; euthanasia of two calves per group for macroscopic and microscopic evaluation of several tissues (spleen, liver, duodenum, jejunum, ilium, cecum and colon) was performed at the end of the experiment. The calves in the T-EO group had a tendency (P = 0.07) of higher body weight when compared to the T-C. Treatment effect and treatment vs day interaction was detected for leukocytes and granulocytes variables, demonstrating a higher count of these cells in the T-EO group on both days (20 and 40), and the same behavior occurred for the distribution amplitude of erythrocytes (RDW). The enzymes alanine transferase (ALT), aspartate transferase (AST) and gamma glutamyl-transferase (GGT) showed higher serum activity in the T-C group (days 20 and 40). The levels of thiobarbituric acid reactive substances (TBARS) were lower in the serum of animals in the T-EO group. For calves in the T-EO group, glutathione S-transferase activity was higher in serum. Haptoglobulin and C-reactive protein levels were lower on days 20 and 40 in T-EO animals when compared to the T-C group. In the macroscopic and microscopic evaluations, which were collected at the end of the experiment after slaughtering the animals, liver and intestine did not show changes for the animals in the T-EO group, unlike the animals in the T-C group, which had moderately firm diffuse consistency of the liver and edema in the mesentery, as well as oxidative stress in tissues (liver, duodenum, jejunum, ileum, cecum and colon). The results concluded that the consumption of a mixture of EOs (essential oils - oregano, thyme, basil and rosemary) minimized the negative effects caused by trichothecenes in dairy calves, thus being an alternative to improving the immunological and antioxidant condition, as well as a possible adsorbent alternative.

Positive cases of bovine genital campylobacteriosis and bovine trichomonosis in the eradication program of La Pampa, Argentina: 2008-2021.

Bovine genital campylobacteriosis, caused by the gram-negative bacteria Campylobacter fetus venerealis, and bovine trichomonosis, caused by the parasite protozoan Tritrichomonas foetus, are venereal diseases that occur with long intercalving periods and abortion. The control of both diseases relies on microbiological testing and culling infected bulls. Vaccination and antibiotic treatment may help in controlling campylobacteriosis but are not recommended for trichomonosis control. Several regions of the world have active control programs for trichomonosis, not campylobacteriosis. In Argentina, the state of La Pampa aims to eradicate trichomonosis and campylobacteriosis by imposing annual diagnostic testing of every bull and slaughtering positive animals. Prior studies indicated a declining trend in the prevalence of campylobacteriosis and trichomonosis in La Pampa. It was also proposed that the prevalence of one disease could be estimated from the prevalence of the other. The purpose of this retrospective analysis of data gathered from 2008 to 2021 was to determine the La Pampa program's efficacy. Descriptive statistics were employed to determine the reason behind the correlation between tricomonosis and campylobacteriosis diagnostic results. The outcomes refute the notion that this program of venereal eradication was a success. Furthermore, an excess of false positives in both diagnoses may have contributed to the correlation between the prevalences of campylobactriosis and trichomonosis. The practice of killing animals without verifying positive results hinders the determination of disease prevalence and results in the death of numerous healthy animals.

Exploring vaginal discharge scoring to assess clinical metritis severity: Comparison between intrauterine dextrose and systemic antibiotics treatments.

The objectives of this study were to assess: 1) differences in the metabolic status, systemic inflammation, daily milk yield, and daily rumination time between Holstein dairy cows with different vaginal discharge scores (VDS) in the first 7±3 DIM, and 2) effects of intrauterine dextrose infusion on metabolic status, systemic inflammation, daily milk yield and daily rumination time in dairy cows with VDS4 and VDS5. Cows (n=641) from a farm located in central Pennsylvania were screened at 7±3 DIM (study d 0) to assess vaginal discharge scores. Vaginal discharge was scored using a five-point scale (i.e., 1- clear fluid, 2- <50% white purulent fluid, 3- >50% white purulent fluid, 4- red-brownish fluid without fetid smell, and 5- fetid red-brownish watery fluid). Cows with VDS4 and VDS5 were blocked by parity and randomly assigned to one of two treatment groups: 1) CONV (VDS4 n=15; VDS5 n= 23): two injections of ceftiofur (per label; 6.6 mg/Kg) 72 h apart; and 2) DEX (VDS4 n=15; VDS5 n=22): three intrauterine infusions of a 50% dextrose solution (1 L/cow) every 24 h. Cows that presented a VDS 1, 2, and 3 were categorized as normal vaginal discharge animals (NOMVDS; n=35) and were randomly selected and matched by parity to CONV and DEX cows. Daily milk yield and rumination time for the first 150 DIM were collected from on-farm computer records. Blood samples were collected to assess haptoglobin (HP) and ß-hydroxybutyrate (BHB) concentrations at study d 0, d 7, and d 14 relative to enrollment. Subclinical ketosis was defined as having a BHB concentration >1.2 mmol/dL at any of the sampling points. The data were analyzed using the MIXED and GLIMMIX procedures of SAS as a randomized complete block design. When comparing cows with different VDS (i.e., NOMVDS, VDS4, VDS5) separately, cows with VDS5 had the highest concentration of HP at enrollment compared to cows with VDS4 and NOMVDS; however, cows with VDS4 had higher concentrations of HP compared to cows with NOMVDS. Cows with VDS4 or VDS5 had a higher incidence of subclinical ketosis compared to cows with NOMVDS (p=0.005; VDS4= 62.08±9.16%; VDS5=74.44±6.74%; NOMVDS=34.36±8.53%). Similarly, daily milk yield (p<.0001; VDS4=30.17±1.32 kg/d; VDS5=27.40±1.27 kg/d; NOMVDS=35.14±1.35 kg/d) and daily rumination time (p=0.001; VDS4=490.77±19.44 min; VDS5=465±16.67 min; NOMVDS=558.29±18.80 min) was lower for cows with VDS4 and VDS5 compared to cows with NOMVDS at 7±3 days in milk. When analyzing HP concentration between treatment groups in cows with VDS4 (p=0.70), VDS5 (p=0.25), or VDS4 and VDS5 combined (p=0.31), there was no difference in HP concentration by study d 14 between treatment groups. Interestingly, when only cows with VDS4 were considered for treatment, both treatments, DEX and CONV, increased the daily milk yield to the levels of NOMVDS cows by 14 days in milk. On the other hand, when only cows with VDS5 were considered for treatment, cows treated with DEX produced, on average, 4.48 kg/d less milk in the first 150 days in milk compared to cows treated with CONV or cows that had NOMVDS. Similarly, when cows with either VDS4 or VDS5 were considered for treatment, DEX treatment also impaired milk yield. These results suggest that cows with either VDS 4 or 5 have an altered inflammatory status, and decreased milk yield and rumination compared to cows with NOMVDS. Furthermore, DEX treatment may have similar effects on daily milk yield and metabolic status compared to CONV in cows with VDS4, while DEX is not recommended for cows with VDS5.

Self-emulsifying drug delivery systems (SEDDS) containing Cymbopogon citratus essential oil: Enhancing the stability and acaricide efficacy against Rhipicephalus (Boophilus) microplus.

The objectives of this study were to develop a self-emulsifying drug delivery system (SEDDS) to enhance the stability and efficacy of Cymbopogon citratus essential oil or lemongrass oil (LEO) against cattle tick larvae and engorged females. The system with the highest oil loading in SEDDS was composed of LEO (23.33%w/w), Tween 80: SGKH 4000 in a 2:1 ratio as surfactant (66.67%w/w), and propylene glycol as co-surfactant (10%w/w). The selected SEDDS-LEO has a particle size of 18.78 nm with a narrow size distribution (polydispersity index of 0.27). Notably, the stability of SEDDS was superior to that of the original oil, both during long-term storage and under accelerated conditions. SEDDS-LEO at oil concentrations ranging from 1.458% to 5.833% w/v showed a significantly higher percentage of egg-laying reduction against adult ticks compared with the original oil at the same concentrations (p < 0.05). Furthermore, SEDDS-LEO demonstrated greater larvicidal efficacy than the original oil, with lower LC50 and LC90 values of 0.91 mg/mL and 1.20 mg/mL, respectively, whereas the original oil's LC50 and LC90 values were 1.17 mg/mL and 1.74 mg/mL, respectively. Our findings indicate that SEDDS-LEO is a promising candidate for use as an acaricide in the control of tick populations in dairy cattle.

Control of Rhipicephalus microplus on taurine cattle with fluralaner in a subtropical region.

BACKGROUND: In Rio Grande do Sul, Brazil, a region with a subtropical climate, Rhipicephalus microplus is present in taurine cattle raised for beef and milk. In addition, ticks resistant to multiple acaricides are present in this region. Recently, fluralaner (isoxazoline) was launched on the market. Thus, there is a need to evaluate the effects of fluralaner for the control of R. microplus on taurine cattle. In addition, occurrence of myiasis by Cochliomyia hominivorax larvae after tick parasitism and weight gain of cattle during the experimental period were evaluated. METHODS: Thirty naturally infested cattle were divided into two experimental groups: T01, treated with fluralaner (2.5 mg/kg) pour-on; T02, control. T01 received fluralaner on Days 0 (early summer in January), 42 and 84 (early autumn), whereas T02, a control group, received palliative treatment with a spray formulation when the group mean was ≥ 30 ticks. Counts of R. microplus females and calculation of the efficacy of fluralaner were performed on Days 3, 7, 14, 28, 35, 42, 56, 70, 84, 98, 112 and 126. The occurrence of myiasis was assessed throughout the study period. In addition, the weight, weight gain and daily weight gain of the animals were evaluated. RESULTS: In the 12 evaluations performed, the parasitic load of T01 was near zero. Fluralaner showed 99.5% efficacy on the 3rd day after the first treatment and 100% efficacy from Day 7 to Day 126. Cochliomyia hominivorax larvae (n = 6; p = 0.0251) were found only in the control group (T02). At the end of the study, the animals subjected to treatments with fluralaner gained 32.8 kg more than the animals in the control group. CONCLUSIONS: Application of fluralaner in summer and autumn, with 42-day intervals between treatments, was effective to control R. microplus on taurine cattle, which also gained more weight than control cattle. Additionally, no cases of myasis were documented in animals treated with fluralaner.

Effect of 2% meloxicam injection in Holstein dairy cows on acute clinical mastitis without systemic symptoms.

This study aimed the efficacy of meloxicam (MX) in treating acute clinical mastitis (ACM) without systemic symptoms in Holstein cows by studying improvement in udder pain, changes in prostaglandin E2(PGE2) and bradykinin (BK) levels in the milk, and milk yield (MY) after healing. Forty-two cows with ACM were randomly assigned to the MX treatment group (T group; n=21) and the control group (C group; n=21). At onset of illness (day 0), the T group received a 0.5 mg/kg subcutaneous (SC) injection of MX whereas the C group received 15 mL SC of saline solution as a placebo. Udder tenderness (UT) was measured, and milk samples were collected on days 0-3. There was little change in the MY of the T group before and after healing, whereas MY in the C group was significantly lower than after healing. UT on day 3 in the T group was significantly lower than that in the C group. PGE2 levels significantly decreased from day 0 to day 3 in both groups. A significant negative correlation between PGE2 and linear score was observed on day 1 in the T group, but not in the C group. In ACM without systemic symptoms, the administration MX may be useful for restoring MY and reducing udder pain after healing.

Antimicrobial resistance in generic E. coli isolated from western Canadian cow-calf herds.

Objective: To examine antimicrobial resistance (AMR) in commensal fecal Escherichia coli (E. coli) from extensively managed beef calves and cows in western Canada and describe the differences among cows and calves in the spring and fall. Animal: Beef cattle, cow-calf. Procedure: Antimicrobial susceptibility testing was conducted on generic E. coli isolates collected from 388 calves and 387 cows from 39 herds following calving in 2021, 419 calves from 39 herds near weaning, and 357 cows from 36 herds at pregnancy testing. Minimum inhibitory concentrations were measured with the NARMS CMV5AGNF plate for Gram-negative bacteria and interpreted using Clinical and Laboratory Standards Institute standard breakpoints for humans. Results: Only 16% (242/1551) of all isolates from 97% (38/39) of herds were resistant to ≥ 1 antimicrobial. Generic E. coli isolates were most commonly resistant to sulfisoxazole (11%, 175/1551), followed by tetracycline (9.3%, 145/1551) and chloramphenicol (3.5%, 55/1551). Isolates from calves in the spring were more likely to be resistant to sulfisoxazole, tetracycline, and chloramphenicol than those from cows in the spring or calves in the fall. Multiclass-resistant isolates were identified in 5% (39/807) of calves. Only 2 isolates recovered from cows were resistant to antimicrobials of very high importance for human health. Conclusion and clinical relevance: Most generic E. coli isolates were pansusceptible. The observed resistance patterns were consistent with earlier studies of AMR from commensal E. coli in this region. Baseline AMR data for cow-calf herds are not currently collected as part of routine surveillance, but are essential to inform antimicrobial use policy and stewardship.

Résistance aux antimicrobiens chez E. coli générique isolé dans des troupeaux vache-veau de l'Ouest canadien. Objectif: Examiner la résistance aux antimicrobiens (RAM) chez Escherichia coli de la flore fécale commensale (E. coli) provenant de veaux et de vaches de boucherie en élevage extensif dans l'ouest du Canada et décrire les différences entre les vaches et les veaux au printemps et à l'automne. Animal: Bovins de boucherie, vache-veau. Procédure: Des tests de sensibilité aux antimicrobiens ont été effectués sur des isolats génériques d'E. coli collectés auprès de 388 veaux et 387 vaches de 39 troupeaux après le vêlage en 2021, de 419 veaux de 39 troupeaux à l'approche du sevrage et de 357 vaches de 36 troupeaux lors des tests de gestation. Les concentrations minimales inhibitrices ont été mesurées avec la plaque NARMS CMV5AGNF pour les bactéries à Gram négatif et interprétées à l'aide des seuils standard pour les humains du Clinical and Laboratory Standards Institute. Résultats: Seulement 16 % (242/1 551) de tous les isolats provenant de 97 % (38/39) des troupeaux étaient résistants à ≥ 1 antimicrobien. Les isolats génériques d'E. coli étaient le plus souvent résistants au sulfisoxazole (11 %, 175/1 551), suivi de la tétracycline (9,3 %, 145/1 551) et du chloramphénicol (3,5 %, 55/1 551). Les isolats provenant des veaux au printemps étaient plus susceptibles d'être résistants au sulfisoxazole, à la tétracycline et au chloramphénicol que ceux provenant des vaches au printemps ou des veaux à l'automne. Des isolats résistants à plusieurs classes ont été identifiés chez 5 % (39/807) des veaux. Seuls deux isolats récupérés chez des vaches étaient résistants à des antimicrobiens de très haute importance pour la santé humaine. Conclusion et pertinence clinique: La plupart des isolats génériques d'E. coli étaient sensibles à l'ensemble des antimicrobiens. Les profils de résistance observés concordaient avec les études antérieures sur la RAM provenant d'E. coli commensal dans cette région. Les données de base sur la RAM pour les troupeaux vache-veau ne sont pas actuellement recueillies dans le cadre de la surveillance de routine, mais elles sont essentielles pour éclairer la politique et la gestion de l'utilisation des antimicrobiens.(Traduit par Dr Serge Messier).

Repurposing of non-steroidal anti-inflammatory drugs for combination therapies to combat multidrug-resistant S. aureus of bovine reproductive tract origin.

Multidrug-resistant bacteria have become the predominant etiology in bovine female reproductive tract infections and thus require effective treatment approaches. The main goal of this study was the molecular detection of mecA, blaZ, tetK, and aacA-aphD genes in Staphylococcus aureus (S. aureus) responsible for methicillin, beta-lactam, tetracycline, and aminoglycoside resistance respectively. Phylogenetic analysis was conducted to check the homology of staphylococcal genes with NCBI sequences. The in-vitro efficacy of non-steroidal anti-inflammatory drugs (NSAIDs) in combination therapies against MDR S. aureus was evaluated using well diffusion assay and checkerboard method. Vaginal swab samples (n = 384) collected from bovines suffering from endometritis, pyometra, and retained placenta were tested for S. aureus. Results showed a 17.96% overall prevalence. Both phenotypic and genotypic resistance was observed among S. aureus isolates with 50.72% and 37.68% isolates being confirmed as methicillin-resistant (MRSA), 36.23% and 18.84% isolates exhibiting beta-lactam, 40.58%, and 27.54% isolates showing tetracycline, and 33.33% and 36.23% isolates showing aminoglycosides resistance based on disc diffusion and gene confirmation, respectively. Phylogenetic analysis indicated homology with previously reported Pakistani isolates suggesting the possibility of MDR S. aureus transmission within and between animals. Synergy testing indicated that combinations of ceftriaxone-ketoprofen (153.77%), ceftriaxone-meloxicam (149.55%), amoxiclav-flunixin meglumine (106.06%), and oxytetracycline-flunixin meglumine (104.47%) showed synergy on well diffusion assay. Based on the fractional inhibitory concentration index by checkerboard method, oxytetracycline-meloxicam and gentamicin-ketoprofen combinations exhibited synergistic interaction. In conclusion, MDR S. aureus resistance was mitigated in-vitro through the combination of antibiotics (oxytetracycline, gentamicin) with NSAIDs (meloxicam, ketoprofen) that could be used to create therapeutic strategies for bovine reproductive issues.

Evaluation of potassium monopersulfate footbath solution for controlling digital dermatitis in lactating dairy cattle. A randomized clinical trial.

Our objective was to assess potassium monopersulfate as a disinfectant used in footbath to control digital dermatitis (DD) in dairy cows. We hypothesized that a potassium monopersulfate solution would control DD. A 180-day randomized negative controlled trial was conducted in a 265-Holstein free-stall facility. Throughout the trial, foot bathing was performed bi-weekly using a split (left vs. right feet) footbath: one tub filled with 1% potassium monopersulfate (treatment), the other with tap water (control). Digital dermatitis lesions were scored during trimming chute examinations of the unwashed hind heels every 90 days using the modified M-scoring system. Digital dermatitis lesions were re-categorized into four variables: 1) inactive; 2) active; 3) any; 4) inactive or absence of DD lesions. Three longitudinal outcomes were characterized: risks of 1) developing a DD lesion; 2) reactivating an inactive DD lesion; 3) development of an inactive or the absence of the DD lesion. A generalized linear model was used to compare the variables and longitudinal outcomes between treated and control groups. Prevalence of active DD lesions increased from 12.5% to 39.9% between days 0 and 90. This significant increase in prevalence justified the discontinuation of the study on day 90 for ethical reasons. There was no statistical difference between treated and control groups for the first outcome (RR: 1.0; 95% CI: 0.62, 1.7), the second outcome (RR: 1.0; 95% CI: 0.62,-1.7); or the third outcome (RR: 0.88; 95% CI: 0.37, 2.1). A 1% potassium monopersulfate footbath solution appears ineffective to control DD in this study.