An assessment of the copper status of dairy herds in the Waikato, Taranaki and Northland in spring and the effects of daily supplementation with copper sulphate

The copper status of dairy herds in the Waikato, Taranaki and Northland regions between 1 August and 30 September was assessed by copper determinations made on composite sera from ten cows in each herd. Comparisons were made between two major groups categorised as as received and supplemented. In the latter, the cows received 2.0-6.0 g/day of copper sulphate orally from late gestation to the end of lactation. Mean copper values were determined from pastures in Taranaki and Northland and from pastures from three soil types in the Waikato. The lowest were in Northland (134.3 micromol/kg) and the highest in Taranaki (173.3 micromol/kg). Calculated dietary available copper levels showed the lowest were from pastures grown on organic soils in the Waikato. These soils also had high molybdenum levels. Serum copper values as received were lowest in Northland (7.30 micromol/l), and were marginal for both Taranaki (9.91 micromol/l) and the Waikato (9.93 micromol/l). The levels in supplemented herds were considerably higher, i.e. from the Waikato 11.7 micromol/l and from Taranaki 11.5 micromol/l. When liver and serum copper levels from paired samples were compared there was a reasonable correlation (r = 0.64) but the standard deviation approximated the mean liver copper level, i.e. 155 +/- 141 micromol/l.     

Predicting beef-longissimus tenderness from various biochemical and histological muscle traits

Our objective was to determine the predictive value of various biochemical and histological traits for tenderness of the longissimus muscle. Data collected from 27 crossbred cattle included longissimus pH, temperature, sarcomere length, total and percentage of soluble collagen, muscle-fiber type and area, cathepsin B and B + L activities, calcium-dependent protease (CDP)-I, -II and inhibitor activities, myofibril fragmentation indices (MFI), Warner-Bratzler shear (WBS) force, sensory-panel tenderness (SPT) ratings and carcass traits. Stepwise regression analyses were performed among breeds or pooled within breeds with WBS and SPT as dependent variables. When MFI were included in the analysis, MFI at d 7 explained 50% of the variation in WBS and SPT at d 14. An additional 19% of SPT was accounted for by the addition of CDP inhibitor d 1 activity and percentage-area of alpha R fibers to the model. However, because variation in MFI was not significant within breed subclasses and MFI could be classified more as a dependent variable, it was removed from the model. This resulted in CDP inhibitor d 1 activity explaining 44% of the variation in WBS and SPT at d 14. Also, percentage-area of beta R fibers, 6 h pH and cathepsin B + L d 14 activity appeared in the model. In addition, CDP inhibitor activity was the only variable to be significant within breed groups. These data suggest that d 7 MFI could be used as a single predictor of d 14 longissimus muscle tenderness; however, CDP inhibitor d 1 activity (a biological event) also may be useful in predicting tenderness.     

Observations on mouse-infective stocks of Cowdria ruminantium: microscopical demonstration of the Kwanyanga stock in mouse tissue and the carrier-status of the Senegal stock in mice

The behaviour of two different stocks of Cowdria ruminantium was investigated in mice. The mouse-pathogenic Kwanyanga stock of C ruminantium was microscopically demonstrated in mice in capillary endothelial cells of the lung, spleen, kidney, liver and brain. Mice of the ninth passage of the Senegal stock, which is infective but not pathogenic to mice, were kept alive for a year. Their blood and homogenised spleens, inoculated intravenously, caused fatal heartwater in a goat. However, the Senegal stock could not be demonstrated microscopically in mice. These results indicate the possible role of rodents in the epidemiology of heartwater.     

Serum prolactin and growth hormone responses to naloxone and intracerebral ventricle morphine administration in heifers

These studies examined responses of serum prolactin (PRL) and growth hormone (GH) to opioid agonist and antagonist administration in heifers. To minimize nonspecific and behavioral effects and to facilitate future studies with specific opioid receptor agonists, a cannula was placed within the third cerebral ventricle of the brain of 4- to 10-mo-old heifers to directly access hypothalamic regions involved in the regulation of PRL and GH secretion. Increasing doses of morphine (M) from 2 to 1,500 micrograms injected into the third cerebral ventricle increased (P less than .001) serum PRL concentrations in a dose-related manner. Growth hormone responses were variable, resulting in elevated (P less than .05) serum concentrations following morphine, but no dose-related effects were apparent. Both PRL and GH responses to 700 micrograms M were absent when an intracerebral ventricle injection of an equimolar dose of naloxone, an opioid receptor antagonist, was administered prior to M. In a replicated 4 x 4 latin square, the effects of intravenous naloxone on PRL and GH responses was tested in young (86 +/- 11 d) and older (234 +/- 6 d) heifers. Naloxone at doses of 1, 2 and 4 mg/kg reduced (P less than .05) serum concentrations of PRL for 45 to 60 min. Mean concentrations of GH tended to be higher (P less than .07) in older heifers All doses of naloxone decreased (P less than .05) serum GH concentrations in older heifers but proved ineffective in younger heifers. There were no differences between doses of naloxone on either PRL or GH. These data suggest that endogenous opioids are involved in the regulation of PRL and GH secretion in heifers.     

MALDI-TOF MS identification of Prototheca algae associated with bovine mastitis

We evaluated the use of MALDI-TOF MS for the identification of 3 major, dairy-associated Prototheca species, namely, Prototheca bovis (formerly P. zopfii genotype 2), P. blaschkeae, and P. ciferrii (formerly P. zopfii genotype 1). The MALDI-TOF MS spectra established for those species were introduced into the reference spectra library of the Bruker Biotyper MALDI-TOF MS analysis software. Next, 31 Prototheca isolates from Holstein cows with mastitis, from herds located in the midwestern area of São Paulo State, Brazil, were subjected to MALDI-TOF MS profiling. MALDI-TOF MS allowed identification of 22 of 27 P. bovis and 3 of 4 P. blaschkeae isolates with scores >2.0, with 5 of 27 P. bovis and 1 of 4 P. blaschkeae isolates identified only to the genus level. With our extended algae database, MALDI-TOF MS can contribute to quick and effective speciation of Prototheca from mastitis cases.     

Alteration in intestinal morphologic features associated with extensive large-colon resection in horses

Light microscopy, morphometry, and scanning electron microscopy were used to examine the mucosal morphologic features of 7 intestinal specimens (3 from the small intestine; 4 from the large intestine) from each of 8 horses 1 year after sham operation (group 1; n = 3) or extensive large-colon resection (group 2; n = 5). Qualitative light microscopic examination did not reveal differences between groups, but morphometry revealed significantly (P less than 0.05) greater intercrypt area and distance in horses with colon resection and this was most pronounced in the cecum and remaining right ventral and dorsal colon. Crypt area and depth were similar for horses with colon resection and sham operation (P greater than 0.05). Qualitative evaluation of the scanning electron micrographs revealed more prominent crypt orifices in the large intestine of horses with colon resection. The larger intercrypt distance in the colon of horses with resection was not an obvious feature of the qualitative evaluation of the surface with scanning electron microscopy. Small intestinal morphologic features were variable and significant differences were not detected between horses with sham operation and colon resection. Horses adapted to extensive large-colon resection within 1 year by increasing the absorptive (intercrypt) surface area of the remaining large intestine.     

Urinary Markers in Healthy Young and Aged Dogs and Dogs with Chronic Kidney Disease

Background: Blood urea nitrogen and serum creatinine concentrations only detect a decrease of >75% of renal functional mass. Therefore, there is a need for markers that allow early detection and localization of renal damage.
Hypothesis: Urinary albumin (uALB), C-reactive protein (uCRP), retinol binding protein (uRBP), and N -acetyl-β- d -glucosaminidase (uNAG) concentrations are increased in dogs with chronic kidney disease (CKD) compared with healthy controls and in healthy older dogs compared with young dogs.
Animals: Ten dogs with CKD, 10 healthy young dogs (age 1–3 years), and 10 healthy older dogs (age > 7 years) without clinically relevant abnormalities on physical examination, hematology, biochemistry, and urinalysis.
Methods: Urinary markers were determined using an ELISA (uALB, uCRP, and uRBP) or a colorimetric test (uNAG). Results were related to urinary creatinine (c). The fixed effects model or the Wilcoxon rank sum test were used to compare the different groups of dogs.
Results: uALB/c, uRBP/c, and uNAG/c were significantly higher in CKD dogs than in healthy dogs. No significant difference was found for uCRP, which was not detectable in the healthy dogs and only in 3 of the CKD dogs. Between the healthy young and older dogs, no significant difference was detected for any of the markers.
Conclusion: The urinary markers uALB/c, uRBP/c, and uNAG/c were significantly increased in dogs with CKD compared with healthy controls. Additional studies are needed to evaluate the ability of these markers to detect renal disease before the onset of azotemia.     

Evaluation of the Feeding Value of Palm Press Fibre Using In Vitro Digestibility Techniques

Palm press fibre (PPF) was obtained from two sources, a small-scale oil palm processing unit and a large-scale factory processing unit, and its chemical composition was determined. In vitro digestibility techniques were used to assess the feeding value of untreated, defatted and sodium hydroxide-treated PPF. For the NaOH treatment, 0.5 g oven-dried PPF was treated for 24 h with 5% NaOH in three ways: treated and not washed (NaNW); treated and washed (NaW); and treated after milling (NAD).The results indicate that, on a dry matter basis, PPF is low in nitrogen (12–13 g/kg), moisture (37–90 g/kg) and ash (53–62 g/kg), but high in ether extract (269–355 g/kg), neutral detergent fibre (532–768 g/kg), acid detergent fibre (375–548 g/kg) and lignin (219 g/kg). The in vitro dry matter digestibility values were low for the samples from both sources, but the large-scale factory-processed PPF had higher in vitro dry matter digestibility (0.215 vs 0.166) and in vitro organic matter digestibility (0.196 vs 0.145). Defatting the PPF and treating it with 5% NaOH solution significantly (p<0.01) improved both the dry matter and organic matter digestibility. Washing the NaOH-treated PPF resulted in a higher digestibility of dry matter as against NaNW or NAD. These results suggest that defatting and treatment with 5% NaOH would improve the feeding value of PPF.     

Enteropathogenicity of Plesiomonas shigelloides and Aeromonas spp. in experimental mono- and coinfection with Cryptosporidium parvum in the intestine of neonatal BALB/c mice

Enteropathogenicity of Plesiomonas shigelloides, Aeromonas hydrophila, A. caviae and A. sobria was studied both in monoinfections and in coinfections with coccidium Cryptosporidium parvum in neonatal BALB/c mice. In monoinfection experiments, neonatal BALB/c mice were orally infected with 7 x 10(7) or 7 x 10(8) CFU, respectively, of a strain of P. shigelloides or a strain of an Aeromonas spp. In coinfection experiments, the neonatal mice were, in addition to being orally infected with one of the four bacterial species, orally infected with an inoculum containing 10(5) oocysts of C. parvum. Results from monoinfections with P. shigelloides revealed long-term colonisation of the neonatal mouse intestine by this pathogen, along with associated pathological lesions. The lesions varied in severity from atrophy to necrosis of the mucosal inner surface of the ileum and colon, with predilection to the colon and brush border of colonic enterocytes. The effects of coinfection of P. shigelloides with C. parvum were characterised by bacteremia and heavy colonisation of the intestine by P. shigelloides. In addition, extensive necrotising inflammatory changes in the ileum and colon were accompanied by diarrhoea and deaths of coinfected mice. In contrast, the results from monoinfections of neonatal mice with Aeromonas spp. showed only a short-term colonisation of the intestine by the pathogen. However, when mice were coinfected with A. hydrophila and C. parvum, then the growth of the bacterial species was prolonged, and occurred in both the spleen and intestine. However, no substantial clinical or histopathological changes were observed in mice, whether monoinfected with Aeromonas spp. or coinfected with C. parvum. Our study suggests that experimental monoinfections of neonatal BALB/c mice with P. shigellodes, Aeromonas spp. and C. parvum, together with coinfections (each bacterial species with the protozoan C. parvum), may serve as a useful model to study the initial steps of gastrointestinal colonisation and diarrhoeal disease syndromes caused by enteropathogenic bacteria and protozoa, individually and in combination.