The Effect of Supplementation with Fresh Browse of Ziziphus mauritiana or Combretum aculeatum on Feed Intake,Nitrogen Utilization and Growth of Grazing Range Sheep

The influence of 0, 60 or 120 min access to a grove of either Ziziphus mauritiana (Ziziphus) or Combretum aculeatum (Combretum) on forage intake and on the digestibility, growth and excretion of nutrients was determined using 40 Oudah rams grazing for 7 h/day on poor-quality dry season pasture in the Sahel. The effects of browse species and browsing duration (0, 30, 60 or 120 min) on the ruminal ammonia content were also evaluated using 8 mature fistulated rams. Ziziphus increased both total digestible organic matter and total dry matter intakes per (kg live weight)^0.75 without decreasing herbage intake, whereas 60 or 120 min access to Combretum reduced herbage intake by 6.3% and 4.2%, respectively. The digestibility of the diet decreased (p<0.05) with the duration of access to the groves. Despite the provision of more nitrogen (N) than in the control diet, ruminal NH₃-N decreased 24 h after browsing commenced. The reduced live weight gain of sheep browsing Combretum may indicate more deleterious compounds in Combretum than in Ziziphus. Ziziphus appears to have more potential than Combretum to increase sheep production in low-input crop/livestock systems.     

Evolution of High-level,Multiple Anthelmintic Resistance on a Sheep Farm in Malaysia

Anthelmintic resistance in nematode parasites of sheep and goats on a government farm in north Malaysia was monitored over a 3-year period (1997–2000). The faecal egg count reduction test (FECRT) was conducted on young sheep at the beginning and end of this period. Changes in management, designed to reduce the selection pressure for the development of anthelmintic resistance, were also implemented during this time. By far the most important parasite problem was Haemonchus contortus. In 1997, this nematode was found to be resistant to levamisole, with suspected resistance to closantel and moxidectin. However, when the FECRT was repeated 3 years later, its resistance status had become much more severe, with resistance to benzimidazole, levamisole and ivermectin, and suspected resistance to moxidectin. This rapid evolution to multiple anthelmintic resistance is a major concern that needs to be arrested. There is an urgent need to evaluate other control strategies that incorporate livestock management, the `smart' use of drugs and non-chemotherapeutic approaches, such as biological control agents.     

The comparative serum disposition kinetics of subcutaneous administration of doramectin, ivermectin and moxidectin in the Australian Merino sheep

This study evaluates the comparative serum disposition kinetics of injectable formulations of doramectin (DRM), ivermectin (IVM) and moxidectin (MXD) in Australian Merino sheep. Thirty-six, 2-year-old sheep were allocated by weight into six groups of six animals. Animals in each group received 200 microg/kg of DRM, MXD, IVM or a combination of two of these drugs by subcutaneous (s.c.) injection. Blood was collected at designated intervals (between 1 h and 40 days after treatment) and the serum analysed by high performance liquid chromatography (HPLC) using fluorescence detection. The results indicated that MXD administration produced a significantly higher maximum serum concentration and a more rapid absorption as compared with DRM and IVM. MXD and DRM had a significantly larger area under the concentration vs. time curve (AUC) than IVM, suggesting a more persistent effect for the former two products in sheep. The AUC for DRM was significantly higher when administered alone as compared with that observed when given in combination with MXD or IVM, suggesting preferential elimination of DRM compared with IVM and MXD from concurrent s.c. administration.     

Modification of spontaneous contractility of smooth muscle preparations from the bovine abomasal antrum by serotonin receptor agonists

The effects of serotonin (5-hydroxytryptamine, 5-HT), a 5-HT2-receptor agonist, alpha-methyl-5-hydroxytryptamine (alpha-M-5-HT) and RS-67506, a 5-HT4 receptor partial agonist, on spontaneous contractility of bovine abomasal smooth muscle preparations were investigated in vitro. Preparations from the abomasal antrum of freshly slaughtered healthy dairy cows were cut parallel to the longitudinal fibres, suspended in isolated organ baths, and concentration-response curves were performed by cumulative application of the 5-HT receptor agonists. Blockade of 5-HT2-induced response was tested with atropine and hexamethonium. Serotonin evoked a significant increase in the area under curve (AUC), whilst the 5-HT2 receptor agonist alpha-M-5-HT significantly increased the AUC and resting tone (RT). RS-67506 induced a significant increase in AUC and RT and a significant decrease in the maximum force. The effect of alpha-M-5-HT was mediated by a muscarinic cholinergic pathway, as the effect of alpha-M-5-HT was inhibited in the presence of atropine but not hexamethonium. It is concluded that 5-HT2 and 5-HT4 receptors are present in the bovine abomasal antrum. Muscarinic receptors are involved in the increase in RT seen after 5-HT2 receptor stimulation.     

Antifungal agents of use in animal health--practical applications

The purpose of this paper is to provide an overview of antifungal agents currently in use in veterinary medicine. The practical applications and the therapeutic regimens that have proved successful in the treatment and prevention of fungal infections in dogs and cats, cattle and sheep, horse, pig, poultry and other birds, rodents, rabbits and fur animals are summarized.     

Privatization of Veterinary Services in Developing Countries: A Review

Increasing fiscal constraints on the government, a lackadaisical performance by public sector animal health and breeding services and pressure from donor partners have prompted the governments of various developing countries to rethink the role of the public sector in the provision of veterinary services. Various countries have started to implement, or have already implemented, privatization of some veterinary services. The results are mixed. It is established that private provision alone is not optimal, and a blend of private and public sector veterinary services is required to utilize the virtues of both.The privatization process has also begun in India. Certain state governments in India are pursuing a cost recovery approach and are encouraging private practitioners to cope with the financial constraints and to deliver broad and effective animal health and breeding services. This paper considers the global aspects of the privatization of veterinary services as well as the scenario in India, so as to gain an insight into the very complex and debatable issue of privatization of veterinary services.