Imbalanced lysine to arginine ratios reduced performance in juvenile cobia (Rachycentron canadum) fed high plant protein diets

Cobia (8.4 ± 0.1 g body weight) were fed to satiation with three test diets of high plant protein‐based ingredients and different lysine to arginine ratios, and one commercial diet (currently used for cobia rearing in Vietnam as a control for growth) for 6 weeks. The test diets contained 206 g marine ingredients kg^?1, including fishmeal, krill meal and fish protein concentrate (in order of high to low inclusion), while the rest of the dietary protein was a blend of soya and pea protein concentrate, wheat protein and sunflower meal. Crystalline lysine and arginine were added in the test diets to produce either a balanced lysine to arginine ratio (BL/A; 1.1) and a high or low lysine to arginine ratio (HL/A; 1.8 and LL/A; 0.8, respectively). There were no significant differences in final body weight, weight gain, feed conversion ratio or protein gain between cobia fed BL/A‐ and commercial control diet (CCT). Cobia fed BL/A diet performed better than fish fed either HL/A‐ or LL/A diet. This was partly due to a higher feed intake and protein and lipid gain in cobia fed BL/A diet as compared to HL/A‐ and LL/A diet.     

Loser cows in Danish dairy herds: definition, prevalence and consequences

During the last few years, many Danish dairy farmers have expressed increasing concerns regarding a group of cows, which we have chosen to term ‘loser cows’. Until now, a loser cow has not been described scientifically. We defined a loser cow on the basis of a clinical examination of the cow. A total of 15,151 clinical examinations were made on 6,451 individual cows from 39 randomly selected, large Danish dairy herds with loose-housing systems using a clinical protocol. Scores for the clinical signs lameness, body condition, hock lesions, other cutaneous lesions, vaginal discharge, condition of hair coat and general condition were converted into a loser cow score. Cows with a loser cow score of 8 or more were classified as loser cows. The overall prevalence of loser cows was 2.15%, 4.50% and 2.98% during the first, second and third round of herd visits, respectively.

The associations between the loser cow state and milk production, mortality, morbidity, culling and workload for the farmer were evaluated using data from herd visits and from the Danish Cattle Database and a number of different statistical techniques. It was concluded that the loser cow state has significant negative consequences for both the farmer and the cow. On average, loser cows yielded 0.61 to 2.24 kg energy corrected milk less per day than non-loser cows depending on parity. Hazard ratio for death or euthanasia was 5.69 for loser cows compared to non-loser cows. Incidence rate ratio for disease treatments was 0.69 for non-loser cows compared to loser cows. Loser cows were often culled in an ‘unfavourable’ way and generally caused extra workload for the farmer.

A simplified version of the loser cow score was evaluated and is recommended for future research and use in practice.     

Effects of Packaging Method on Salt-Cured Cod Yield and Quality During Storage

Different packaging conditions of salt-cured cod fillets were studied during 2-years chilled storage. Yield and quality of salt-cured Atlantic cod fillets packed in sealed polystyrene boxes or in traditional cardboard boxes were compared. After 4 months, yield decreased by approximately 10% and decreased further when packed in cardboard boxes. Lipid oxidation was low after 12 months, and no microbiological spoilage was registered. The total amount of bacteria in the fish reduced with storage time, independent of packaging. The reddish color of halophilic bacteria was detected after 7–8 weeks at 18°C, but not if packed with MAP.     

Micro-scaled high-throughput digestion of plant tissue samples for multi-elemental analysis

Background  

Quantitative multi-elemental analysis by inductively coupled plasma (ICP) spectrometry depends on a complete digestion of solid samples. However, fast and thorough sample digestion is a challenging analytical task which constitutes a bottleneck in modern multi-elemental analysis. Additional obstacles may be that sample quantities are limited and elemental concentrations low. In such cases, digestion in small volumes with minimum dilution and contamination is required in order to obtain high accuracy data.     

Chemical and sensory quantification of geosmin and 2-methylisoborneol in rainbow trout (Oncorhynchus mykiss) from recirculated aquacultures in relation to concentrations in basin water

Globally, aquaculture systems with water recirculation experience increasing problems with microbial taste and odor compounds (TOCs) such as geosmin and 2-methylisoborneol (MIB). This study investigated the content of geosmin and MIB in water and the flesh of 200 rainbow trouts from eight recirculated aquaculture systems in Denmark. TOC content in the fish flesh was measured by a dynamic headspace extraction method and was evaluated by a sensory panel. The results showed significant correlations between TOC content in water and fish and between chemical analysis and sensory perception. When geosmin exceeded 20 ng/L in the water, 96% of the fish had an intense muddy flavor, but below 10 ng geosmin/L, 18% of the fish (only 3% in special depuration ponds) had an intense muddy flavor. The results indicate that TOC levels <10 ng/L will ensure that a negligible portion of the fish obtains an unpalatable taste and flavor due to TOCs.     

Energy and Resources: A plan is outlined according to which solar and wind energy would supply Denmark's needs by the year 2050

Two possible futures for the industrial world may be distinguished: (i) Large amounts of low-cost energy become available and the more energy-intensive methods for extracting resources from lowergrade deposits continue to sustain industrial expansion until either the environmental impact becomes unacceptable or ultimate limits, such as climate disruptions, put an end to such growth. (ii) The cost of nonrenewable energy resources continue to rise, but a fixed amount of energy from continuous sources may be utilized at constant cost. In this case a lower production level may be set by the amount of energy that is available from renewable sources, and society may thus have to be reshaped with energy economization in focus. If it is possible to choose between these two alternatives, the choice should be based on a discussion of the pros and cons of each one, and in particular on the desirability of having to process an increasing fraction of the earth's crust in search of raw materials in order to maintain growth as long as possible. However, the availability, of the first option is far from certain and it thus seems reasonable to plan for the second alternative. I have tried to propose such a plan for a small, homogeneous geographical region, namely Denmark. The ceiling on the consumption of energy from continuous sources is chosen in accordance with the criterion of not having to convert a major part of the land area to energy-collecting systems. The proposed annual average energy consumption of 19 gigawatts by the year 2050 corresponds to solar energy collecting panels (in use only 50 percent of the time) with an area of roughly 180 square kilometers and a windmill swept area of about 150 square kilometers. These (vertical) areas constitute less than 1 percent of the total land area. The selection of solar or wind energy for different applications has been based on known technology and may be subject to adjustments. The project has been shown to be economically feasible according to estimates of the cost of various alternatives during the 25-year depreciation period adopted. However, the initial cost per energy unit produced is higher than that for most of the alternatives, so that action is not expected to be taken immediately as a result of purely private initiative. In a public economic evaluation, other factors must be considered in addition to the cost of energy per kilowatt-hour. At present, Denmark has over 10 percent of its labor force out of employment and a substantial deficit on its balance of payments, so that an early start on the solar and wind energy project, based on national industry, would have additional payoffs compared with energy systems based on imported technology or imported fuels. Several factories that are now being closed down as a result of the economic crisis could be adapted to the production of parts for solar or wind power systems, and the building industry, badly hit by unemployment, would receive legitimate work.     

Effects of tetracycline and zinc on selection of methicillin-resistant Staphylococcus aureus (MRSA) sequence type 398 in pigs

An in vivo experiment was conducted to evaluate the effects of tetracycline and zinc on pig colonization and transmission of methicillin-resistant Staphylococcus aureus (MRSA) sequence type (ST) 398. Eight piglets naturally colonized with MRSA ST398 and 8 MRSA-negative piglets of the same age and breed were assigned to three groups treated with tetracycline and zinc (Group 1), zinc (Group 2) or tetracycline alone (Group 3) and one non-treated group (Group 4), each containing two MRSA-positive and two MRSA-negative animals. Two additional non-treated control groups composed of only MRSA-positive (Group 5) and MRSA-negative (Group 6) animals were used to check for stability of MRSA carriage status. Nasal swabs and environmental wipes were collected on Days 0, 7, 14, and 21, and the occurrence of MRSA in each sample was quantified by bacteriological counts on Brilliance? MRSA agar. Significantly higher nasal MRSA counts were observed in the zinc-treated (p=0.015) and tetracycline-treated (p=0.008) animals compared to the non-treated animals. Environmental MRSA counts appeared to increase over time in Groups 1 and 2 but such an increase was not statistically significant. MRSA-negative animals housed with MRSA-positive animals became positive in all groups, whereas the carriage status of the animals in Groups 5 and 6 did not change. This study demonstrates that feed supplemented with tetracycline or zinc increases the numbers of MRSA ST398 in the nasal cavity of pigs. Transmission of MRSA from positive to negative animals housed within the same pen was not influenced by exposure to these agents.     

Pastoralists’ perceptions of feed scarcity and livestock poisoning in southern rangelands, Ethiopia

A survey was conducted between April and July 2007 to generate information on dry season feeding management and livestock poisoning in the southern rangelands of Ethiopia. A total of 119 pastoralists were interviewed using a semi-structured questionnaire. Moreover, additional information was obtained through informal discussions. The study revealed that pastoralists have rich knowledge of natural resource management and utilization and employ various strategies such as migration, collection of grasses and pods, and cutting branches to overcome feed scarcity during dry/drought periods. Migration of livestock and people to areas with better grazing is the widely used strategy. However, the implementation of this strategy is diminishing as a result of changes such as bush encroachment, expansion of settlements, and crop cultivation in dry-season grazing lands. The respondents also indicated the presence of poisonous plants in the rangeland, and about 20 such plants were identified by the respondents. Various species and classes of livestock are reported to be affected by toxic plants particularly in the dry and early rainy seasons when feed is in short supply. A more extensive survey is required to document all poisonous plants in the rangelands and to identify the major toxic principles in the different species. Future development interventions should consider the prevailing constraints and potentials of the rangelands with active participation of the pastoralists.     

The need for built-in validation of surveillance data so that changes in diagnostic performance of post-mortem meat inspection can be detected

Time trends in animal-disease surveillance often are evaluated on the basis of crude estimates of apparent prevalence. In addition to possible changes in the true prevalence of the condition, changes in apparent prevalence over time might reflect changes in sensitivity and/or specificity of the diagnostic classification used. To illustrate this, comparative post-mortem meat inspection data from four Danish slaughter plants sampled in 1993-1994 and 1997-1998 were used to obtain latent-class model estimates of the sensitivity and specificity of traditional and extended post-mortem meat inspection of visceral and parietal chronic pleuritis (CP), respectively.True prevalence of CP was estimated for each study period and slaughter plant by latent-class models. Estimated sensitivities of traditional post-mortem meat (TPM) inspection ranged from 28.8 to 61.4% (1993-1994) and 39.2 to 87.3% (1997-1998). An increase in sensitivity with time was seen for all slaughter plants. Estimated sensitivities of extended post-mortem meat (EPM) inspection ranged from 85.7 to 94.8% (1993-1994) and 73.8 to 93.0% (1997-1998). All estimated specificities were >93.3%.The possible association of the estimated true prevalence of CP with time (1993-1994 versus 1997-1998) was investigated with a logistic-regression model with random effects. A slight, but non-significant decrease in the odds of CP from 1994 to 1998 was found (odds ratio=0.9).In this and similar situations, one should consider conducting ongoing double-classification of samples of units followed by statistical estimation of true prevalences, sensitivities and specificities, so that decisions can be based on such estimates rather than on crude apparent prevalences.     

Physiological Predictors in Calves of Dairy Breeds: Part 1. Genetic Parameters of Basal and Induced Growth Hormone Secretion

Abstract

Genetic variation in plasma growth hormone (GH) concentration before and after GRF (growth hormone releasing factor) stimulation was studied in young bulls (N=284) and heifers (N=212), the progeny of 53 sires of four dairy and dual-purpose breeds (Danish Jersey, Red Dane, Danish Friesian and Danish Red and White). Male and female calves were reared, fed and tested on separate experimental stations; thus sex, station and feeding were completely confounded effects. The animals were tested at about 9 months of age, after a 24 h fast. GH concentration was measured in serial plasma samples collected for 1 h before and 1 h following intravenous administration of 2.0 ug synthetic GRF(1–29)NH₂/kg live weight^>0.75. Prior to statistical analysis, concentrations were log_e-transformed. Response variables were BASELINE (mean GH in -15, -5 and 0 min samples) and PEAK (mean GH in 10, 15 and 20 min samples). A statistical model taking at least three generations of ancestral relationships into account was used to estimate variance and covariance components for traits in male and female calves by use of restricted maximum likelihood methods.

Heritability of BASELINE was low (0.04 ± 0.12) in males but high in females (0.60 ± 0.16). The heritability of PEAK was high in both sexes (males, 0.42 ± 0.16; females, 0.60 ± 0.16). Genetic correlations between the same trait measured in males and females were low for BASELINE (r _g = 0.32±0.55) but high for PEAK (r _g = 0.82±0.15). Within sex, BASELINE and PEAK were both highly genetically correlated (males, r _g=0.62 ± 0.40; females, r _g= 1.00 ± 0.07).

We conclude that growth hormone concentration is a highly heritable trait in juvenile cattle of both sexes, and that GRF stimulation is benificial to the uncovering of genetic differences among animals.