Effects of stocking density on growth and skin quality of grower Nile crocodiles (Crocodylus niloticus)

Intensive Nile crocodile (Crocodylus niloticus) farming operates with considerable variation in housing and stocking density. In this study, current commercial stocking densities for crocodilians were investigated using 261 grower-phase crocodiles (15 months old, average total body length 94.5 cm, and average weight 2.7 kg). Low (2.60 m2 per crocodile), medium (1.24 m2 per crocodile), and high (0.41 m2 per crocodile) stocking densities were tested. Growth, morphometric measures, Fulton’s condition scores and skin qualities were assessed over a six-month (May - November 2017) period. High stocking density had no adverse effects on the growth of grower Nile crocodiles. Crocodiles stocked at medium and high densities outperformed those that were stocked at low density in Fulton’s body condition scores, change in body condition from the start to the end of the trial, and feed conversion efficiencies. However, the high and, to a lesser extent, the medium stocking densities resulted in lower skin quality scores compared with those in the low-density treatment because of teeth marks from more aggressive behaviour. The results indicated that the medium pen density treatment is closer to the ideal than either the high or low stocking density groups. Stocking densities that provide 0.41 m2 per crocodile or less should be avoided because of lower skin quality scores, which weigh more heavily than growth and feed efficiency responses in the financial viability of commercial crocodile farming in typical South African production systems

Digestibility of lucerne hay with special reference to experimental technique in digestion trials (second report)

(1) In a continuation of the study of the digestibility of the same lucerne hay by the same steers at different times further evidence of a period influence on digestibility was obtained. This influence could be reduced or eliminated by following a simplified technique in planning digestion trials with different feeding stuffs. (2) The digestion of lucerne hay by bovines would seem to improve with age in these animals.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

The influence of processing on the efficiency of proteins

Employing an improved nitrogen balance method the influence of mild heat treatment on the digestibility and biological value of a mixture of plant proteins has been determined. The heat treatment resulted in a small though significant improvement in the digestibility of the proteins. Protein quality was, however, not affected.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the alimentary tract of merino sheep in South Africa. VI. The role of infusoria in ruminal digestion with some remarks on ruminal bacteria

(1) A technique is described for the preservation and counting of ruminal infusoria. (2) Reactions of specific infusoria as well as total infusorial populations to changes in the diet of stable fed sheep were investigated. (3) Seasonal fluctuations of ruminal infusoria of sheep grazing on the veld are described. The amount of protein available in the pasture was shown to have a significant influence on the density of the infusorial population. (4) Data are presented comparing the density and types of infusoria in veld-grazing sheep and different species of antelopes in their natural state. (5) The digestion of maize starch within an infusorium from material in vivo is described. The brown glycogen-like granules formed within the foodsac and plasma of the infusorium have been shown to be glycogen synthesizing bacteria and not actual glycogen granules as hitherto accepted. (6) The rate of digestion of starch within the rumen was shown to be the same whether infusoria were present or not. It was therefore concluded that infusoria do not accelerate the rate of digestion of starch and that they merely act as hosts to starch attacking bacteria and bacterially secreted diastatic enzymes ingested by the organism. (7) That infusoria assist in the digestion of cellulose could not be proved. It was concluded that the digestion of cellulose within the body of the infusorium is primarily due to cellulose digesting bacteria ingested by the infusorium.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Digestibility of lucerne hay with special reference to experimental technique in digestion trials

Five steers were used to determine the digestion coefficients of the Dry Matter, Crude Protein, and Crude Fibre of lucerne hay during five separate periods. The analysis of the resultant data shows that period has no influence on the coefficients of Crude Protein, but there is some evidence of a period influence on the coefficients of digestion of Dry Matter and Crude Fibre. In consequence it is concluded that the Latin Square or Randomized Block Technique of Fisher should be adhered to wherever possible, but since period effects tend to be very small, an alternative technique is suggested in the interests of simplicity.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Studies on the alimentary tract of Merino sheep in South Africa. IV. Description of experimental technique

1. The importance is stressed of a more intensive study of digestion in ruminant animals, whose food, apart from being disintegrated by enzymes liberated from the digestive tract itself, is first of all subjected to a predigestion, the significance of which is as yet not fully recognised. Through the action of a varied and rich bacterial flora accompanied by large numbers of different species of infusoria, the food mass is exposed to carefully controlled fermentation occurring within the forestomachs and similar in many respects to that occurring in silage fermentation. 2. In order to study the different stages in the process of digestion, the use of permanent bowel fistulae in experimental animals has been widely resorted to in the past, and an account is given of some of the experimental methods which have been used. 3. An account is given of our experimental technique which involves the use of suitable ebonite fistula tubes and the creation of permanent “closed” fistulae at different levels of the digestive tract of adult Merino sheep. 4. In this study attention has thus far been devoted mainly to some phenomena exhibited within the rumen of fistula sheep, kept on various controlled diets. 5. A method has been devised whereby any pressure change occurring within the rumen could be accurately recorded on slow moving kymographs and the limits of fluctuation in the motility of this organ registered under varying conditions. 6. The technique is described whereby samples of ingesta could repeatedly be collected from the rumen and subjected both to chemical and bacteriological study. 7. By the use of a large water manometer attached to the rumen fistula, continuous volume recording of gas from the rumen could be conducted under constant pressure. Likewise repeated sampling of gas for chemical analysis could simultaneously be undertaken. 8. Methods are described whereby different materials could be administered through the fistula opening directly into the rumen. By enclosing small samples of a variety of foodstuffs within cylindrical bags made from thin natural silk and subsequently suspending these within the food mass of the rumen, the rate at which disintegration took place as also its nature, could be followed microscopically.The articles have been scanned in colour with a HP Scanjet 5590; 300dpi. Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format

Treatment rationale for dogs poisoned with aldicarb (carbamate pesticide)

The treatment rationale for dogs poisoned by aldicarb is reviewed from a pharmacological perspective. The illegal use of aldicarb to maliciously poison dogs is a major problem in some parts of the world. In South Africa, it is probably the most common canine poisoning treated by companion animal veterinarians. Aldicarb poisoning is an emergency and veterinarians need to be able to diagnose it and start with effective treatment immediately to ensure a reasonable prognosis. Successful treatment depends on the timely use of an anti-muscarinic drug (e.g. atropine). Additional supportive treatment options, including fluid therapy, diphenhydramine, benzodiazepines and the prevention of further absorption (activated charcoal) should also be considered. Possible complications after treatment are also briefly discussed

Bioaccumulation of aluminium and iron in the food chain of Lake Loskop, South Africa

Concentrations of total aluminium (Al) and iron (Fe) were determined in Lake Loskop over a period of four months in 2009 in samples of phytobenthos, phytoplankton, macroinvertebrates, amphibians and fish. The highest concentrations of Al and Fe were measured in the filamentous algae Spirogyra fluviatilis (Hillse) and Spirogyra adanata (Kütz), (Al=18,997.5 mg kg-1 dry weight and Fe=22,054.2 mg kg-1 dry weight) in the riverine zone of the lake with a near-neutral water average pH of 7.3. However, a negative correlation exists between the Al and Fe concentrations measured in the filamentous algae in comparison with the corresponding concentrations of these elements in the water column of the riverine zone. The Al concentrations in the macroinvertebrate families collected ranged from 140.6 to 385.7 mg kg-1 dry weight, with the highest values measured for Al and Fe in the family Gomphidae (385.7 and 1710.0 mg kg-1 dry weight, respectively) in comparison to other macroinvertebrate families sampled. Al and Fe concentrations (2580 and 10,697 mg kg-1 dry weight) in the stomach contents of adult Oreochromis mossambicus fishes were much higher in comparison with adult Micropterus salmoides fishes (98.5 and 439.6 mg kg-1 dry weight), respectively. In all cases of dissected fish species either white or yellow body fat was observed, thus in none of the samples both type of body fats occurred simultaneously. The concentrations of total Al and Fe in the different organs of O. mossambicus were along a mean sequence of intestine>yellow body fat>brain>gills>liver>heart>white body fat, while the mean sequence of total Al and Fe in M. salmoides was: intestine>gills>liver>heart>brain>white body fat. From the levels of Al detected in the yellow body fat of the studied fish species O. mossambicus, we suggest that this phenomenon may be related to the feeding habits of this species. Furthermore, the intake of certain species of phytobenthos by O. mossambicus could have played a role in the bioaccumulation of Al in the food chain and the possible development of pansteatitis in predators at higher trophic levels. © 2011 Elsevier Inc. All rights reserved.Article in Pres

Three case studies involving Leptospira interrogans serovar pomona infection in mixed farming units

Three case studies involving Leptospira interrogans serovar pomona outbreaks within mixed farming systems in South Africa are described. On 2 farms, pigs constituted the main enterprise with cattle and sheep of secondary importance. On each of these 2 farms, abortion due to L. pomona in sows was confirmed by culture, and antibody titres to pomona were detected in cattle, sheep, horses and dogs. On the 3rd farm, a piggery was of secondary importance to cattle farming. Abortion and death in cows occurred on this farm and serology showed titres to various serovars, including pomona. L. pomona was also isolated from bovine urine, an aborted bovine foetus and kidneys from slaughtered pigs. This particular case study was regarded as clinically atypical in that adult Jersey cattle died of acute leptospirosis in a semiarid region of South Africa. In all 3 case studies, the poor management of pig effluent and of the drinking water and its sources played a pivotal role\ud in the transmission of the disease. Inadequate vaccination of animals against Leptospira and poor record-keeping within the secondary farming enterprises were also contributing factors to the spread of leptospirosis