Adult Dairy Cattle Research Articles

Síndrome do corpo estranho em bovinos – revisão de literatura

Foreign body syndrome is an inflammatory disease, caused by the ingestion of a perforating foreign body, most often metallic. Adult dairy cattle are most affected. Depending on the direction that the foreign body takes when it reaches the reticulum, it can reach adjacent organs and cause reticulum peritonitis or reticulum traumatic pericarditis. It can cause unspecific signs such as fever, changes in rumen motility and cardiac signs. The diagnosis consists of observation of clinical signs, evidence of pain, ultrasound, hematology, blood biochemistry and analysis of cavitary effusions. The treatments normally used are conservative, with or without magnet and rumenotomy.

Percutaneous Ultrasound Guided Cholecystocentesis and Microbiological Analysis of Bile in Chronic Diarrhoea of Cattle

Background: Chronic diarrhoea is a frequently presenting complaint by the cattle owners and some presents as non-responsive to routine treatment. Such cases are often a diagnostic challenge because of wide ranging etiologies. In Indian context few data is available on prevalent causes of chronic diarrhoea in bovines. Salmonellosis is one of the important cause of chronic diarrhoea in crossbred cattle. Therefore, the study was conducted to investigate the role of Salmonella in chronic diarrhoea of crossbred cattle and to determine microbiological profile of bile in cattle with chronic idiopathic diarrhoea. Methods: Twenty (n=20) adult dairy cattle presented with the history of chronic diarrhoea at Large Animal Clinics, GADVASU, Ludhiana from September 2015 to June 2016 were selected for the study. Case histories were recorded, faecal, blood and bile samples were collected from 20 animals. Bile was collected through ultrasound guided cholecystocentesis (PUC) from 20 cattle and five healthy cattle. The faecal and bile samples were cultured for isolation and identification of bacterial pathogens using selective and non-selective media with special emphasis on isolation of Salmonella spp. Microscopic examination of faeces were done to rule out parasitic cause of diarrhoea and for acid-fast bacilli (AFB). The serum samples were employed to detect antibodies against Mycobacterium avium spp paratuberculosis using serum ELISA. Result: Investigations have showed culture of bile and faecal did not yield Salmonella spp; however E.coli was isolated from 6 cows (30%), Klebsiella spp in 9 cows (45%) and Pseudomonas spp from 1 cow (5%) from bile culture of diarrhoeic cattle. PCR results of E.coli culture from bile showed hlyA virulence genes which expected band at 534 bp however these isolates were negative for other virulence gene of E.coli. It was observed in this study that bactibilia was associated with chronic diarrhoea in three fourth of the diarrhoeic cattle.

Recording the heart beat of cattle using a gradiometer system of optically pumped magnetometers

Monitoring of heart rate has the potential to provide excellent data for the remote monitoring of animals, and heart rate has been associated with stress, pyrexia, pain and illness in animals. However monitoring of heart rate in domesticated animals is difficult as it entails the restraint of the animal (which may in turn affect heart rate), and the application of complex monitoring equipment that is either invasive or not practical to implement under commercial farm conditions. Therefore accurate non-invasive automated remote monitoring of heart rate has not been possible in domesticated animals. Biomagnetism associated with muscle and nerve action provides a promising emerging field in medical sensing, but it is currently confined to magnetically-shielded clinical environments. In this study, we use biomagnetic sensing on commercial dairy cattle under farm conditions as a model system to show proof-of-principle for non-contact magnetocardiography (MCG) outside a controlled laboratory environment. By arranging magnetometers in a differential set-up and using purpose-built low-noise electronics, we are able to suppress common mode noise and successfully record the heart rate, the heart beat intervals and the heart beat amplitude. Comparing the MCG signal with simultaneous data recorded using a conventional electrocardiogram (ECG) allowed alignment of the two signals, and was able to match features of the ECG including the P-wave, the QRS complex and the T-wave. This study has shown the potential for MCG to be developed as a non-contact method for the assessment of heart rate and other cardiac attributes in adult dairy cattle. Whilst this study using an animal model showed the capabilities of un-shielded MCG, these techniques also suggest potentially exciting opportunities in human cardiac medicine outside hospital environments.

Uso de enrofloxacina en un brote de anaplasmosis en ganado lechero en Ijuí-RS: informe del caso

Anaplasmosis is a disease caused by the bacterium Anaplasma marginale, transmitted mainly by ticks in cattle herds around the world, in addition to transmission by hematophagous and iatrogenic insects. In this work, the objective was to describe an outbreak of anaplasmosis in six adult dairy cattle in the region of Ijuí-RS, showing success in the clinical resolution for patients treated with enrofloxacin-based antimicrobial therapy. According to the anamnesis, the animals that had died on the property, had shown clinical signs such as: loss of appetite, jaundiced mucous membranes and on the other day the clinical condition worsened, until death. The animal seen in a veterinary consultation, showed the same clinical signs and the clinical examination, apathy, dehydration, pallor, jaundiced ocular, oral, nasal and vulvar mucous membranes, dehydration and hypersalivation. The main complaint for the consultation was the reluctance to eat, weight loss and decreased milk production, considering that the animal had already been treated for bovine parasitic sadness 2 days ago, with diminazene diaceturate and oxytetracycline. However, the diagnosis was confirmed by blood smear and the necropsy findings performed on another animal that died on the same property, with jaundiced mucous and serous, with an excessive increase in the size of the liver, spleen and gallbladder, as well as the presence of blood with an aqueous aspect and by the blood smear which resulted in the presence of bacteria of the genus Anaplasma. Antimicrobial therapy based on enrofloxacin associated with lactated ringer fluid therapy, blood transfusion, vitamins and organic modifier was instituted for the treatment of bovine patients. Due to other cases already reported in the region, it is believed that there are some strains of the bacteria Anaplasma marginale, which are resistant to oxytetracycline, thus, enrofloxacin appears as a new treatment alternative for dairy cattle with anaplasmosis, refractory to the use of oxytetracycline.

Urine protein-to-creatinine ratio in cattle with subclinical renal disease.

Urinalysis is not routinely used in bovine medicine, and there is no evidence as to whether urine protein-to-creatinine ratio (UPC) could be used for the diagnosis of renal diseases in cattle. The goal of the study was to determine alterations in UPCs observed with different subclinical renal diseases in clinically healthy cattle and to investigate whether UPC can efficiently differentiate cattle with and without subclinical renal pathology. Kidney and urine samples from 57 clinically healthy adult dairy (44) and beef (13) cattle were collected after slaughter. Urinary protein and creatinine concentrations were measured in an automatic analyzer, and urinary-specific gravity (USG) was measured using a temperature compensated refractometer. Kidney samples underwent histopathologic examination, and the cattle were classified as NL (no renal lesion) and L (lesions detected even in one kidney). Based on USG, the cattle were divided into the Normal USG (≥1.020) and Low USG (<1.020) groups. The cattle with either histopathologic lesions or low specific gravities were considered to have renal disease. Renal lesions were detected in 37 cattle. UPC values were significantly affected (P<.05) by USG values, and not by the type of lesion detected, breed, or age, and their interactions (P>.05). The analysis revealed that a UPC of ≥0.19 provided an optimal cut-off point for the differentiation between normal animals and those with renal disease with 66.0% sensitivity and 90% specificity. The UPC calculation is a useful tool for the differentiation of normal cattle and those with renal disease. A UPC of less than 0.19 is associated with the absence of renal damage, whereas higher values raise suspicion for renal disease.

Effect of vaccination with a Mannheimia haemolyticasubunit vaccine on milk yield in lactating dairy cows

Vaccination of adult lactating dairy cattle can have a negative impact on milk production. Decreased milk production may occur from a combination of the cow’s immune response, endotoxin level in the vaccine, and the impact of cattle handling. A randomized clinical trial utilized 3 treatment groups to examine changes in milk production following vaccination with a Mannheimia haemolytica subunit vaccine (MHSV; Nuplura PH, Elanco Animal Health) using 972 lactating dairy cows on a single Midwestern dairy: a vaccinated group (MHSV, n=315); a placebo-treated control (saline, n=342); and a negative control group (no injections, n=315). The decline in milk across a 3 d post-treatment period for the saline group was 0.5 lb (0.2 kg) greater than the negative control cows, but the difference was not significant (P=0.57). The decline in milk during the same time period for cows in the MHSV group was 1.5 lb (0.7 kg) more than the negative control, (P=0.02). The declines between the saline group (0.5 lb; 0.2 kg) and the MHSV group (1.5 lb; 0.7 kg) were not significantly different (P=0.17).

Morphometrical study of bovine kidneys with and without mild histological lesions

The objective of this study was to determine the renal dimensions in adult cows and to investigate whether they are affected by the breed, the age of the animals and the presence of subclinical renal histopathological lesions. The kidneys of 57 adult female dairy (44 Holstein) and beef (13 Limousine-Cross) cattle aged≥2years obtained at an abattoir were used for the purpose of the study. The greatest pole-to-pole length and the maximum width were measured with a digital caliper. A renal sample obtained from a central pole of each kidney underwent histopathologic examination. Renal dimensions were significantly affected by the breed and the age of the animals without however been affected by the presence of mild histopathologically detected lesions. The renal size was significantly higher in Holstein cows compared to Limousine-Cross ones and significantly lower in cows aged more than 6years than the youngest ones. Left kidney was shorter and wider in the majority of animals. These results indicate that breed and age of animals are significant factors that affect renal size in cows. They further prove that mild histologically detected renal lesions do not significantly alter renal dimensions. Although no significant difference was detected, the obtained results tend to confirm the well documented morphological difference (asymmetry) in cattle between right and left kidney.

Epidemiological Features of Adult Dairy Cattle Diarrhea Based on Analysis of Etiological Diagnosis Data in Japan from 2004 to 2013

Epidemiological Features of Adult Dairy Cattle Diarrhea Based on Analysis of Etiological Diagnosis Data in Japan from 2004 to 2013

Data-driven approach to using individual cattle weights to estimate mean adult dairy cattle weight

BackgroundKnowledge of accurate weights of cattle is crucial for effective dosing of individual animals and for reporting antimicrobial usage. For the first time, we provide an evidence-based estimate of the...

Prevalence and risk factors for corkscrew claw syndrome in dairy cattle

The objective of this study was to determine the prevalence and associated risk factors for an emerging hoof lesion in growing heifers and adult dairy cattle with no prior reports in the peer-reviewed literature. Corkscrew claw syndrome (CCS) is not the corkscrew claw that we used to see affecting the rear lateral claws of multiparous cows who were victims of poor housing and hoof care. Nor is it the mild corkscrew of the front medial claw that we commonly recognize. Rather, corkscrew claw syndrome is the combination of corkscrew deformities of the medial claws of both the rear and front feet in combination, and it occurs in heifers predominantly, rather than older cows. The condition can be so severe by the time that the heifer calves, the rear medial claw is the dominant weight bearing claw. The anatomical changes that result in this condition appear to be permanent and unrepairable. The pedal bones are irreversibly changed, developing bony exostoses and becoming narrower and rotated within the claw capsule. For that reason, affected herds will see this syndrome affecting all age groups, starting in growing age heifers and following through all the way to the oldest cows in the herd.

Risk factors associated with cows' lying time, stall and cows' own cleanliness in smallholder dairy farms in Kenya

Background and Aim:The welfare of animals kept in livestock production systems has raised concerns around the world. Adult dairy cattle require adequate rest and spend approximately 12 h/day lying down. This cross-sectional study aimed to determine the stall factors and management practices affecting cows’ lying time, stall cleanliness, and cows’ cleanliness (udder and upper leg), in smallholder dairy cows in Meru County of Kenya.Materials and Methods:A total of 106 milking cows from 73 farms were assessed for daily lying time and cleanliness. Data loggers were used to record the lying time of cows for 3 days. Stall, udder, and upper leg cleanliness were assessed using a 5-score system: 1 (very clean) to 5 (very dirty). Management information was acquired using a questionnaire that was administered face-to-face to the farmers in their native Kimeru language. Univariable and multivariable linear and logistic regression models were fit to determine factors associated with cows’ lying time and dichotomized stall and cows’ own cleanliness, respectively.Results:The mean daily lying time was 10.9±2.2 h, and the mean stall cleanliness score was 2.4±1.0. The mean average cleanliness scores of the udder and upper legs were 1.9±0.7 and 2.5±1.1, respectively. Overall, 35% of the stalls were categorized as dirty (>2.5), whereas 13% and 47% of the cows had udder and leg cleanliness scores >2.5, respectively. From the final multivariable models (p<0.05), daily lying time increased by 1.0 h for cows older than 5.25 years versus younger cows. Conversely, lying time decreased by 1.0 h with stall cleanliness scores >2.5 and by 1.6 h with poorly positioned neck rails. In an interaction term, addition of new bedding at least once a day without removing stall manure at least once a day decreased the daily lying time of the cows by 1.5 h, whereas failure to add new bedding at least once a day but removing stall manure at least once a day decreased the lying time of the cows by 1.2 h. Farm-level risk factors for stall dirtiness (>2.5) included delayed cleaning of the alley (odds ratio [OR]=6.6, p=0.032), lack of bedding (OR=4.9, p=0.008), and standing idle and/or backward in the stall (OR=10.5, p=0.002). Stalls categorized as dirty (OR=2.9, p=0.041) and lack of bedding (OR=2.7, p=0.065) were cow- and farm-level risk factors for dirtiness of the udder (>2.5), respectively, whereas the stall being dirty (OR=2.3, p=0.043) was the only risk factor (cow level) for dirtiness of the upper legs (>2.5).Conclusion:It was recommended that farmers should pay attention to the specific factors identified regarding the stall design (e.g., neck rail position) and bedding/manure management that impact the cleanliness of cows and their lying time.

Effects of transdermal flunixin meglumine on experimentally induced lameness in adult dairy cattle

Lameness is a common animal health condition with significant production and welfare implications. The transdermal formulation of flunixin meglumine is the only approved drug for pain control in cattle in the United States. Thirty adult dairy cows were enrolled in a study to determine the effect of transdermal flunixin on cattle with induced lameness. Cows were allocated to 1 of 3 treatment groups, with 10 cows per group: lameness and flunixin (L+F), lameness and placebo (L+P), or sham induction and placebo (S+P). An arthritis-synovitis was induced in the distal interphalangeal joint of the left hind lateral digit, using 20 mg of amphotericin B, 6 h before the application of treatment. Cows enrolled into the sham induction group had 4 mL of isotonic saline injected into the joint. Cows were dosed with transdermal flunixin at 3.33 mg/kg (1 mL/15 kg), or a placebo at 1 mL/15 kg, every 24 h for 3 d. The first treatment of flunixin or placebo was considered the start of the study, identified as time 0 h. Data were collected from all cows for 120 h following the initial treatment application. Outcome measures included plasma cortisol; substance P; visual lameness assessment; mechanical nociception threshold (MNT), presented as difference between left and right feet; infrared thermography (IRT), presented as difference between left and right feet; and gait analysis using a pressure mat. Cortisol concentrations were lower for the L+F group starting at 1.5 h after drug administration. Substance P levels showed no evidence for treatment differences among groups. Differences between the left hind MNT and right hind MNT were detected, with S+P having the lowest difference at -0.04 kilograms-force (kgf; 95% CI: -1.86 to 1.78 kgf), and L+P having the highest at -2.96 kgf (95% CI: 1.55 to 4.36 kgf). The L+F group was intermediate at -2.08 kgf (95% CI: 0.89 to 3.27 kgf). Similarly, when the difference between the maximum temperatures of the coronary band were examined via IRT, the L+P group had the highest difference at 1.64°C (95% CI: 1.02 to 2.26°C), with the L+F and S+P groups measuring 0.57°C (95% CI: 0.06 to 1.08°C) and 0.53°C (95% CI: -0.2 to 1.25°C) respectively. We found no evidence for differences among treatment groups when analyzing force, contact pressure, step impulse, or stride length. Based on differences in MNT, IRT, and cortisol, transdermal flunixin is an effective analgesic agent for induced lameness. Multiple doses of transdermal flunixin may be required to be clinically effective, based on MNT and IRT data. Further investigation of transdermal flunixin and its analgesic effects is warranted in naturally occurring lameness.

Laboratory findings of tracheal wash and bronchoalveolar lavage in normal adult dairy cattle

ABSTRACT Tracheal Wash (TW) and bronchoalveolar lavage (BAL) are not well documented in adult cattle and published studies were undertaken on diseased animals aiming at isolating the causative agent of respiratory diseases. This study was undertaken to establish the normal cytological and microbiological findings of TW and BAL in normal adult cattle and compare between the laboratory analysis findings of both techniques. Eighteen healthy adult cattle were divided into two groups. BAL was completed the first group (n = 10) and TW was completed the second group (n = 8). Normal cytological findings of TW in healthy adult cattle were found to be primarily neutrophils (42.7 ± 35.7)% intermixed with lower numbers of columnar epithelial cells (26.2 ± 34.8)%, alveolar macrophages (14.7 ± 15.4)%, squamous epithelial cells (10 ± 28.6)%, lymphocytes (6.8 ± 16.1)% and rarely seen eosinophils (0.1 ± 0.0)% with a total cell count of 457 ± 310.1 cells/µl. Cytological findings of BAL were found to be mainly alveolar macrophages (94.3 ± 3.9)%, intermixed with lower number of neutrophils (4.3 ± 3.9)% and lymphocytes (1.3 ± 1.2)% and rarely seen eosinophils (0 ± 0.1)% with a total cell count of 238 ± 169 cells/µl. There are remarkable differences in TW and BAL cytological findings and the degree of contamination was higher in TW samples than that seen in BAL lavage.

Evaluating the temporal and situational consistency of personality traits in adult dairy cattle.

Recent research suggests that personality, defined as consistent individual behavioral variation, in farm animals could be an important factor when considering their health, welfare, and productivity. However, behavioral tests are often performed individually and they might not reflect the behavioral differences manifested in every-day social environments. Furthermore, the contextual and longer-term temporal stability of personality traits have rarely been investigated in adult dairy cattle. In this study, we tested three groups of lactating Holstein cows (40 cows) using an individual arena test and a novel object test in groups to measure the contextual stability of behavior. Among the recorded individual test parameters, we used seven in the final analysis, which were determined by a systematic parameter reduction procedure. We found positive correlations between novel object contact duration in the group test and individual test parameters object contact duration (Rs = 0.361, P = 0.026) and movement duration (Rs = 0.336, P = 0.039). Both tests were repeated 6 months later to investigate their temporal stability whereby four individual test parameters were repeatable. There was no consistency in the group test results for 25 cows tested twice, possibly due to group composition changes. Furthermore, based on the seven individual test parameters, two personality traits (activity/exploration and boldness) were identified by principal component analysis. We found a positive association between the first and second tests for activity/exploration (Rs = 0.334, P = 0.058) and for boldness (Rs = 0.491, P = 0.004). Our results support the multidimensional nature of personality in adult dairy cattle and they indicate a link between behavior in individual and within-group situations. The lack of stability according to the group test results implies that group companions might have a stronger influence on individual behavior than expected. We suggest repeating the within-group behavioral measurements to study the relationship between the social environment and the manifestation of personality traits in every-day situations.

Epidural co-administration of neostigmine and lidocaine or xylazine enhances systemic sedation but not perineal analgesia in adult dairy cows

The aim of this study was to evaluate the behavioural, clinical and analgesic effects of epidural neostigmine in adult dairy cattle. Five healthy, adult Holstein-Friesian dairy cows received five different treatments in a cross-over design with one-week washout period as follows: 2% lidocaine alone (0.22 mg/kg), neostigmine alone (10 μg/kg), neostigmine-lidocaine (10 μg/kg and 0.11 mg/kg), neostigmine-xylazine (10 μg/kg and 0.05 mg/kg) and 0.09% saline alone (6 ml). Analgesia of the perineal region was assessed using the superficial and deep muscle pin-prick techniques. The onset and duration of analgesia and the degree of analgesia, sedation and ataxia were assessed before drug administration (T0) and thereafter at T15, T30, T60, T120 and T180. In addition, cows were monitored for any behavioural or clinical abnormalities over the course of the entire study. Signs of agitation, increased salivation and increased frequency of defecation were observed in cows administered neostigmine epidurally alone or in combination with lidocaine or xylazine. The epidural administration of neostigmine alone did not result in any analgesic effects in any of the cows. Analgesia appeared significantly faster (P ≤ 0.05) in the lidocaine group compared to the neostigmine-lidocaine and neostigmine-xylazine groups. The duration of analgesia produced by neostigmine-xylazine was significantly longer (P ≤ 0.05) than that produced by lidocaine alone or neostigmine-lidocaine. Neostigmine produced a significant degree of sedation (P ≤ 0.05) when administered epidurally alone or in combination with lidocaine or xylazine. The epidural administration of neostigmine alone did not result in any signs of ataxia, while the epidural administration of lidocaine alone, neostigmine-lidocaine and neostigmine-xylazine resulted in variable degrees of ataxia. There were no significant changes in any of the clinical parameters. In conclusion, neostigmine can be co-administered epidurally with lidocaine or xylazine for routine standing surgical procedures in adult dairy cows to enhance sedation but not analgesia.

Short- and long-term association between individual levels of milk antibody against Ostertagia ostertagi and first-lactation heifer’s production performances

It is agreed that exposure of adult dairy cattle to helminths on pasture can negatively affect production performances as milking herd. Young animals, especially replacement heifers, represent the future of a dairy farm and are among the most vulnerable to helminth infections in a dairy herd. For this reason, dairy farmers tend to frequently treat heifers against helminths, although the impact of helminths on heifers’ production performances is still poorly understood. Using different epidemiological and serological tools, this study examines the relationship between heifer exposure to helminths on pasture and production performances over time. During a one-year period, 1,454 individual milk samples were collected from first-lactation heifers in England and tested for Ostertagia ostertagi (O. ostertagi) antibodies. After controlling for other confounders, increasing milk antibody levels against O. ostertagi were significantly associated with decreased milk yield at sampling but not at day 305 of heifer lactation. We did not observe any relationship between milk antibody levels against O. ostertagi in heifers and yields in fat and protein. However, heifers with a high level of milk antibodies against O. ostertagi were more likely to produce dead calf at first calving and present a delay in second calving. Moreover, these heifers had significantly higher levels of milk antibodies against Mycobacterium paratuberculosis (M. paratuberculosis) during their first lactation and were more likely to die before the end of the study. We argue that epidemiological approaches can be useful but must be complemented by other methodologies to better understand the impact of helminth infections in dairy heifers. In order to address the complex dynamics of helminth infections in dairy cattle production we require more comprehensive approaches that include triangulation between data sources and interdisciplinary studies.

21 Evaluation of Transdermal Flunixin Meglumine on Experimentally Induced Lameness in Adult Dairy Cattle.

21 Evaluation of Transdermal Flunixin Meglumine on Experimentally Induced Lameness in Adult Dairy Cattle.

Antimicrobial consumption on dairy herds and its association with antimicrobial inhibition zone diameters of non-aureus staphylococci and Staphylococcus aureus isolated from subclinical mastitis

The main objectives of this study were to quantify the consumption of antimicrobials on a convenience sample of dairy herds and to determine the association between herd-level antimicrobial consumption and inhibition zone diameters (IZD) of non-aureus staphylococci and Staphylococcus aureus isolates from subclinical mastitis cases. Also, the association between the IZD of non-aureus staphylococci and Staph. aureus isolates within a herd was studied. Antimicrobial consumption data on 56 Flemish dairy farms were obtained between 2013 and 2014 by so-called garbage can audits and expressed as antimicrobial treatment incidence (ATI), with the unit of ATI being the number of defined daily doses animal (DDDA) used per 1,000 cow-days. The average total ATI in adult dairy cattle for all active substances was 18.73 DDDA per 1,000 cow-days and ranged from 6.28 to 42.13 DDDA between herds. The ATI of critically important (for human health) antimicrobials was 6.91 DDDA per 1,000 cow-days; that is, 37% of total antimicrobial consumption. The average ATI for intramammary therapy of (sub)clinical mastitis, intramammary dry-cow therapy, and systemically administered therapy was 5.20, 6.70, and 6.73 DDDA, respectively. The IZD of 239 non-aureus staphylococci and 88 Staph. aureus isolates originating from milk samples from cows with subclinical mastitis collected on selected dairy herds were determined using Kirby-Bauer disk diffusion and ranged between 6 and 42 mm. Because only a limited number of clinical breakpoints (Clinical and Laboratory Standards Institute) and epidemiological cut-off values (European Committee on Antimicrobial Susceptibility Testing) are available for mastitis-causing bacteria in bovine, IZD were used as a proxy for antimicrobial resistance. Inhibition zone diameters of non-aureus staphylococci for cefquinome, a critically important β-lactam antibiotic, were negatively associated with the ATI of critically important β-lactam for systemically administered therapy and positively with the ATI for intramammary therapy of (sub)clinical mastitis of critically important β-lactam antimicrobials. Only for neomycin was a positive association between the IZD of non-aureus staphylococci and Staph. aureus isolates within the same herd observed.

Foot-and-mouth disease virus transmission dynamics and persistence in a herd of vaccinated dairy cattle in India.

Foot-and-mouth disease (FMD) is an important transboundary disease with substantial economic impacts. Although between-herd transmission of the disease has been well studied, studies focusing on within-herd transmission using farm-level outbreak data are rare. The aim of this study was to estimate parameters associated with within-herd transmission, host physiological factors and FMD virus (FMDV) persistence using data collected from an outbreak that occurred at a large, organized dairy farm in India. Of 1,836 regularly vaccinated, adult dairy cattle, 222 had clinical signs of FMD over a 39-day period. Assuming homogenous mixing, a frequency-dependent compartmental model of disease transmission was built. The transmission coefficient and basic reproductive number were estimated to be between 16.2-18.4 and 67-88, respectively. Non-pregnant animals were more likely to manifest clinical signs of FMD as compared to pregnant cattle. Based on oropharyngeal fluid (probang) sampling and FMDV-specific RT-PCR, four of 36 longitudinally sampled animals (14%) were persistently infected carriers 10.5months post-outbreak. There was no statistical difference between subclinical and clinically infected animals in the duration of the carrier state. However, prevalence of NSP-ELISA antibodies differed significantly between subclinical and clinically infected animals 12months after the outbreak with 83% seroprevalence amongst clinically infected cattle compared to 69% of subclinical animals. This study further elucidates within-herd FMD transmission dynamics during the acute-phase and characterizes duration of FMDV persistence and seroprevalence of FMD under natural conditions in an endemic setting.

Clinical haematology and biochemistry profiles of cattle naturally infected with Theileria orientalis Ikeda type in New Zealand

AIMS: To present the haematology and biochemistry profiles for cattle in New Zealand naturally infected with Theileria orientalis Ikeda type and investigate if the results differed between adult dairy cattle and calves aged <6 months.METHODS: Haematology and biochemistry results were obtained from blood samples from cattle which tested positive for T. orientalis Ikeda type by PCR, that were submitted to veterinary laboratories in New Zealand between October 2012 and November 2014. Data sets for haematology and biochemistry results were prepared for adult dairy cattle (n=62 and 28, respectively) and calves aged <6 months (n=62 and 28, respectively), which were matched on the basis of individual haematocrit (HCT). Results were compared between age groups when categorised by HCT. Selected variables were plotted against individual HCT, and locally weighted scatterplot smoothing (Loess) curves were fitted to the data for adult dairy cattle and calves <6 months old.RESULTS: When categorised by HCT, the proportion of samples with HCT <0.15 L/L (severe anaemia) was greater for adult dairy cattle than for beef or dairy calves, for both haematology (p<0.002) and biochemistry (p<0.001) submissions. There were differences (p<0.05) between adult dairy cattle and calves aged <6 months in the relationships between HCT and red blood cell counts, mean corpuscular volume, mean corpuscular haemoglobin, mean corpuscular haemoglobin concentrations, lymphocyte and eosinophil counts, and activities of glutamate dehydrogenase and aspartate aminotransferase. In both age groups anisocytosis was frequently recorded. The proportion of blood smears showing mild and moderate macrocytosis was greater in adults than calves (p=0.01), and mild and moderate poikilocytosis was greater in calves than adults (p=0.005).CONCLUSIONS AND CLINICAL RELEVANCE: The haematology and biochemistry changes observed in cattle infected with T. orientalis Ikeda type were consistent with extravascular haemolytic anaemia. Adult dairy cattle were more likely to be severely anaemic than calves. There were differences in haematology and biochemistry profiles between adult dairy cattle and calves, but most of these differences likely had a physiological rather than pathological basis. Overall, the haematological changes in calves aged <6 months appeared less severe than in adult dairy cattle.