Evaluation of veld potential in east griqualand using beef cattle under two grazing management systems

Abstract

Beef production from veld, in the short term, was found to be greater under a continuous grazing system than under a rotational grazing system. Average daily gains decreased from a maximum in late‐spring and the highest three‐year mean value was 0,5 kg/animal/day. Livemass gains/ha were highest at a stocking rate of 2,2 animals/ha and were 131,4 kg/ha under continuous grazing and 88,6 kg/ha under rotational grazing. Estimated mean maximum gains/ha were 0,78 kg/ha/day at a stocking rate of 2,5 animals/ha under continuous grazing and 0,55 kg/ha/day at a stocking rate of 1,7 animals/ha under rotational grazing. However, optimum economic stocking rates were estimated to occur below those where beef production/ha was maximum.     

Ultrasonography of the urinary tract in 29 female Saanen goats

The left and right kidneys, ureters, urinary bladder and urethra of 29 female clinically healthy Saanen goats were examined via transcutaneous and transrectal ultrasonography. In order to establish reference values the examinations were performed using a 5.0 MHz linear transducer to scan the right caudal costal part of the abdominal wall, right and left dorsal flanks and right and left inguinal regions of standing goats. A 5.0 MHz intracavity probe was used for transrectal ultrasonographic examination of the urinary bladder and urethra. The kidneys were examined in longitudinal and cross section and assessed subjectively. They could usually be seen from the 12th intercostal space on the right side and dorsal right flank. The right kidney was 8.0 ± 0.67 cm long and the left was 8.4 ± 0.64 cm long. The ureters could not be visualized in any of the goats. The length of the urinary bladder was 5.1 ± 1.38 cm, and its largest cross-sectional diameter was 2.6 ± 1.01 cm. The urethra was seen in 23 goats and appeared as echogenic lines with no visible lumen. The transition from the neck of the bladder to the internal urethral orifice extended beyond the brim of the pelvis in only one goat.     

RNA‐transfected CD40‐activated B cells as a vaccine strategy in canine malignancies

Introduction: Cell‐based vaccine strategies using dendritic cells as cellular adjuvant have entered phase III trials in humans and have been found to be safe, feasible, and potentially efficacious. Canine patients are generally smaller than adult human patients, which makes production of canine dendritic cell (DC) vaccines problematic, given patient size and the small number of available DC precursors. Here we describe feasibility studies of a novel cell‐based vaccine strategy which uses CD40‐activated B‐cells (CD40‐B) loaded with RNA. This strategy is based on our observations that RNA‐transfected human CD40‐B can drive anti‐tumor T cell responses. One advantage of using CD40‐B cells is the ability to expand this cell population ex vivo, allowing for the numbers of cells required for therapeutic vaccines. Methods: Twenty milliliters of blood were drawn from 6 normal dogs and 5 canine lymphoma patients. Peripheral blood mononuclear cells were separated by Ficoll centrifugation. Culture conditions for B cell activation were optimized using CD40‐ligand, canine IL‐4, and Toll‐like receptor stimulus with CpGoligodinucleotides (ODN). Cyclosporine was added to eliminate peripheral T lymphocytes. Proliferation and activation of CD40‐B cells were demonstrated by CFSE dilution of B cells quantified by flow cytometry. Gene transfer was achieved by mRNA electroporation. Results: Marked in vitro stimulation and proliferation of canine peripheral B cells were achieved with soluble trimeric CD40L, canine IL‐4, and ODN. CD40‐B cells showed dramatic upregulation of MHC class II molecules and CD21 (B‐cell activation marker). After two weeks in culture, cells were negative for CD3 and CD4. Canine CD40‐B cells were efficiently transfected with mRNA, with >60% of CD40‐B expressing green fluorescent protein after GFP mRNA electroporation. Conclusion: RNA‐transfected CD40‐B cells can be efficiently generated from normal and tumor‐bearing dogs. These results provide rationale to test tumor RNA‐transfected CD40‐B as a novel therapeutic approach to treating canine malignancies. Clinical trials in canine lymphoma have been proposed.     

Balloon dilation of oesophageal strictures in two horses

Oesophageal strictures in 2 horses with chronic recurrent oesophageal obstruction or choke was diagnosed by endoscopy and contrast radiography. Balloon dilation of the strictures was performed under endoscopic and fluoroscopic guidance. Follow‐up endoscopic and radiological examinations performed 6 weeks after the procedure showed clear dilation of the strictures. Both horses did not have any recurrence during follow‐up periods of 10 and 12 months.     

The influence of colostral antibodies on the postvaccinale humorale immune response in neonatal calves

The aim of this study was to evaluate the efficiency of vaccination of young calves and to see whether maternal antibodies may influence the immunological response in calves. For this project 20 matched-pairs of cows and their offspring were selected. Of each pair, one cow received a placebo 8 and 4 weeks before term (group A) and the other was vaccinated against Feline Leucose Virus, FeLV, with Leucogen? (group B). All calves received colostrum from their respective mother shortly after birth and all calves were vaccinated with Leucogen? 10 days after birth. Blood samples from the cows and calves were taken during the whole study period (till four weeks after calf vaccination). An ELISA test was done in the lab to define the FeLV antibody concentration. 30 % of the vaccinated cows showed a seroconversion, 13 out of 20 vaccinated cows passed the antibodies onto their calves. 11 calves of group B did not convert in comparation of only 4 of group A. All seroconverted calves had low antibody concentration before their vaccination. Calves of group B with a low passive antibody level at the beginning showed a higher seroconversion as compared to calves with higher antibody concentrations of the same group. Two thirds of the calves without maternal antibodies reacted adequately to the vaccination. Therefore, an early vaccination of calves can be recommended.