Interaction between nutrition and gastrointestinal parasitism in sheep

Effects of gastrointestinal nematode infection on metabolism and nutrient utilisation in sheep are reviewed. Infection induces protein deficiency by increasing the demand for amino acids in the alimentary tract while reducing supply through depression of appetite. Mechanisms through which improved protein nutrition could improve the performance of the host are then discussed. Opportunities for capitalising on such effects are limited by our rudimentary understanding of the cell-mediated immune response in gastrointestinal epithelial tissue. Both resistance of the animal to larval establishment and performance in the face of larval challenge can be enhanced by improved protein nutrition. However, enhanced immune responses may not necessarily be synonymous with improved productivity except at luxurious levels of protein intake, because of apparently competing demands for protein. Such levels of protein nutrition are difficult to achieve in pasture-based systems, because of the protein limiting role of the rumen. Work with protein-protecting tannins to overcome this limitation is discussed. The much more limited evidence for effect of mineral nutrition, particularly copper (Cu), molybdenum (Mo), cobalt (Co) and phosphorus (P), on outcome of larval challenge is also reviewed.     

Magnesium does not limit ewe milk production

Abstract

Extract

Madam:— I wish to draw to the attention of readers my serious reservations aQout the very strong statement made by the authors Bray, Burton and Cox in their paper “Magnesium supplementation of lactating ewes and lamb growth”. ⁽²⁾ Bray, A.R., Burton, R.N. and Cox, B.T. 1987. Magnesium supplementation of lactating ewes and lamb growth. N.Z. vet. J., 35: 55–57. [Taylor &; Francis Online], [Web of Science ®] , [Google Scholar] They claim categorically that “magnesium levels below 0.7 m mol/serum did not limit production” in sheep. This supposes that the supplement provided to half of 26 lactating ewes with serum levels below this threshold was in fact sufficient to reverse the hypomagnesaemia and provide adequate Mg for some critical function. There are very good grounds for belieiving that the supplement - once daily oral administration of 12.5 mg magnesium chloride - was totally inadequate to do this. The daily dietary requirement of the particular sheep can be calculated to be between 2.5–3.5 g Mg/ day ⁽¹⁾ Agricultural Research Council. 1980. The Nutrient Requirements of Ruminant Livestock, Slough: Commonwealth Agricultural Bureaux.  [Google Scholar] and 10.2 g Mg/d. ⁽³⁾ Grace, N.D. 1983. The Mineral Requirements of Grazing Ruminants, N.Z. Society of Animal Production. Occasional Publication 9 [Google Scholar] The supplement provided much less than 1% of this by comparison with either standard. My calculation would suggest that the minimum realistic supplement would have been 1.0–1.5 g Mg/d or 80–120 times the dose given. Comparisons with supplementation work with dairy cattle, in which 10 g Mg/d are given ⁽³⁾ Grace, N.D. 1983. The Mineral Requirements of Grazing Ruminants, N.Z. Society of Animal Production. Occasional Publication 9 [Google Scholar] to overcome hypomagnesaemia and its consequences, would have suggested that the equivalent dose in sheep would have been 1.5 g Mg/d.     

Musculoskeletal responses of 2-year-old Thoroughbred horses to early training. 6. Bone parameters in the third metacarpal and third metatarsal bones

AIM: To determine the effect of a known training regimen on the size and mineral content of the third metacarpal (Mc3) and third metatarsal (Mt3) bones of 2-year-old Thoroughbred horses trained on racetracks.

METHODS: Mc3 and Mt3 of seven horses trained on grass and sand tracks were scanned at several sites using conventional quantitative and peripheral computed tomography (CT). Bone dimensions and density in the diaphysis and epiphysis were compared with those from seven untrained horses. Calcein label was injected in two clusters, during Weeks 9 and 12. The extent and rate of diaphyseal modelling was determined by confocal fl uorescent microscopic examination of thin plane parallel sections of the mid-metacarpal region.

RESULTS: Volumetric bone mineral density (BMDv) of the epiphysis was markedly higher and of the diaphysis was slightly higher in trained compared with untrained horses, but greater bone size in the trained horses had the greatest effect on an index of bone strength. Active osteons, defined as Haversian systems containing calcein label, were fewer, of smaller diameter at the time of calcein injection, and had a greater bone apposition rate in trained than in untrained horses.

CONCLUSIONS: Conventional training of 2-year-old Thoroughbred racehorses over a 13-week period had a significant effect on bone size, density and strength index when compared to untrained horses.

CLINICAL RELEVANCE: Bone responded rapidly to early training. The data provide reference values and sites for use in longitudinal studies of commercial training regimens.     

Prevalence of and risk factors for isolation of meticillin‐resistant Staphylococcus spp. from dogs with pyoderma in northern California,USA

Background – Canine pyodermas associated with meticillin‐resistant Staphylococcus spp. (MRS) have increased in prevalence over the past decade. Hypothesis/Objectives – To compare the prevalence of MRS isolation from dogs with superficial pyoderma at a primary care clinic (PCC) and those at a tertiary care facility (VMTH) in California, USA, and identify associated risk factors. Animals – Client‐owned dogs from the VMTH (80 dogs) and the PCC (30 dogs). Methods – Aerobic bacterial culture and antibiotic susceptibility were performed on swab specimens collected from dogs, and meticillin resistance was determined using microdilution methods according to Clinical and Laboratory Standards Institute guidelines. A mecA gene PCR assay was used to confirm meticillin resistance when possible. Results – Of 89 staphylococcal isolates from the VMTH, 34 (38.2%) were meticillin resistant. In 31 dogs, pyoderma persisted, and one or more follow‐up isolates were obtained. The species isolated and drug susceptibility changed unpredictably during treatment. Of 33 PCC isolates, nine (27.3%) were meticillin resistant. Multiple drug resistance was identified in 41 of 53 (77.3%) MRS isolates from the VMTH and five of nine from the PCC. The sensitivity and specificity of PCR for the detection of meticillin resistance was 34 of 39 (87%) and 86 of 87 (99%), respectively. Risk factors for meticillin resistance for both sites were antibiotic treatment within the last year (P = 0.001), and for VMTH, hospitalization of dogs within the last year (P = 0.001). Conclusions and clinical importance – The prevalence of meticillin resistance was not different between VMTH and PCC isolates (P = 0.29). Previous antimicrobial therapy was an important risk factor for the isolation of MRS at both sites.     

Overview of suspected adverse reactions to veterinary medicinal products reported in South Africa (March 2004 - February 2006)

The Veterinary Pharmacovigilance and Medicines Information Centre is responsible for the monitoring of veterinary adverse drug reactions in South Africa. An overview of reports of suspected adverse drug reactions received by the centre during the period March 2004 to February 2006 is presented. A total of 21 reports was received in the 2-year period, continuing the decline in the number of reports to a lower figure than in any previous year. This is surprising considering the legal obligation of the veterinary professionals to report all adverse drug reactions. Once again the majority of reports involved suspected adverse reactions that occurred in dogs and cats. Most of the products implicated were stock remedies. Veterinarians predominantly administered these products.     

Modelling exploration of the future of European beech (Fagussylvatica L.) under climate change—Range,abundance, genetic diversity and adaptive response

We explored impacts of climate change on the geographic distribution of European beech by applying state of the art statistical and process-based models, and assessed possible climate change impacts on both adaptive capacity in the centre of its distribution and adaptive responses of functional traits at the leading and trailing edge of the current distribution. The species area models agree that beech has the potential to expand its northern edge and loose habitat at the southern edge of its distribution in a future climate. The change in local population size in the centre of the distribution of beech has a small effect on the genetic diversity of beech, which is projected to maintain its current population size or to increase in population size. Thus, an adaptive response of functional traits of small populations at the leading and trailing edges of the distribution is possible based on genetic diversity available in the local population, even within a period of 2–3 generations.     

Early weaning of cuttlefish (Sepia officinalis,L.) with frozen grass shrimp (Palaemonetes varians) from the first day after hatching

The suitability of early weaning cuttlefish using frozen grass shrimp, and its effects on growth and mortality was determined in a 50‐day experiment. Three food groups were used. One group (C) was fed with live prey until 25th DAH and weaned with frozen prey until the end of the experiment. In the other two groups, weaning started at the fifth DAH (W5) and first DAH (W1), also with frozen diet. Significant differences were found between C and the remaining treatments (P < 0.05) for mean wet weight (MWW), instantaneous growth rate (IGR), biomass (B) and mortality at the 25th and the 50th DAH. Despite the lower growth (~1/3 of the achieved with live food) and higher mortality (3% obtained by C versus 23% in the W1 and W5 groups), C cuttlefish presented a similar weight gain tendency to W1 and W5 groups after weaning. This is the first record of early acceptance (at the first DAH) of frozen food by cuttlefish hatchlings. These differences could be related with digestive enzymes of cuttlefish and prey, changes in nutritional composition and amount of captured prey, etc. Future research should also address the effects of this early weaning on cuttlefish life cycle.