Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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    We will mail you new results for this query: keywords==Stocking density
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Influence of stocking density on growth, digestive enzyme activities, immune responses, antioxidant of Oreochromis niloticus fingerlings in biofloc systems
Liu, Gang ; Ye, Zhangying ; Liu, Dezhao ; Zhao, Jian ; Sivaramasamy, Elayaraja ; Deng, Yale ; Zhu, Songming - \ 2018
Fish and Shellfish Immunology 81 (2018). - ISSN 1050-4648 - p. 416 - 422.
Antioxidant - Biofloc - Digestive enzyme activities - Immune responses - Stocking density - Tilapia

A 120-day feeding trial was conducted to evaluate the effect of different stocking densities on growth, the non-specific immunities, antioxidant status and digestive enzyme activities of Oreochromis niloticus fingerlings under a zero-water exchange biofloc system. Tilapias (0.51 ± 0.05 g) were randomly distributed in twelve tanks, each with 300 L water. The experimental design was completely randomized using three replications with four treatments 166 orgs m−3 (LD, low density), 333 orgs m−3 (MD, middle density) and 600 orgs m−3 (HD, high density) with glucose added as biofloc groups, and a clear water group without glucose added as a control 333 orgs m−3. The fish cultured in LD and MD group showed higher final body weight. For the digestive enzymes, the lipase, trypsin, and amylase activities were all depressed in HD group and control group. Regarding the immune and antioxidant abilities, significantly lower values (P < 0.05) of the lysozyme, complement 3, and glutathione were observed for the fish that reared in the control group and HD group. The stress indicator, the cortisol, 5-hydroxytryptamine, and glucose concentrations were also depressed in HD group and control group, meanwhile the alanine aminotransferase, aspartate transaminase and alkaline phosphatase were all higher in HD group and control group. The significant higher survival was observed in the LD and MD group after Vibrio harveyi challenge test. The results of the experiment indicated that the biofloc in situ had the effects of anti-crowding stress.

Exploration feeding and higher space allocation improve welfare of growing-finishing pigs
Vermeer, Herman M. ; Dirx-Kuijken, Nienke C.P.M.M. ; Bracke, Marc B.M. - \ 2017
Animals 7 (2017)5. - ISSN 2076-2615
Animal welfare - Environmental enrichment - Feeding method - Pig - Stocking density
Lack of environmental enrichment and high stocking densities in growing-finishing pigs can lead to adverse social behaviors directed to pen mates, resulting in skin lesions, lameness, and tail biting. The objective of the study was to improve animal welfare and prevent biting behavior in an experiment with a 2 × 2 × 2 factorial design on exploration feeding, stocking density, and sex. We kept 550 pigs in 69 pens from 63 days to 171 days of life. Pigs were supplemented with or without exploration feeding, kept in groups of seven (1.0 m2/pig) or nine animals (0.8 m2/pig) and separated per sex. Exploration feeding provided small amounts of feed periodically on the solid floor. Skin lesion scores were significantly lower in pens with exploration feeding (p = 0.028, p < 0.001, p < 0.001 for front, middle, and hind body), in pens with high compared to low space allowance (p = 0.005, p = 0.006, p < 0.001 for front, middle and hind body), and in pens with females compared to males (p < 0.001, p = 0.005, p < 0.001 for front, middle and hind body). Males with exploration feeding had fewer front skin lesions than females with exploration feeding (p = 0.022). Pigs with 1.0 m2 compared to 0.8 m2 per pig had a higher daily gain of 27 g per pig per day (p = 0.04) and males compared to females had a higher daily gain of 39 g per pig per day (p = 0.01). These results indicate that exploration feeding might contribute to the development of a more welfare-friendly pig husbandry with intact tails in the near future.
Economic evaluation of stall stocking density of lactating dairy cows
Vries, Albert De; Dechassa, Hailegziabher ; Hogeveen, Henk - \ 2016
Journal of Dairy Science 99 (2016)5. - ISSN 0022-0302 - p. 3848 - 3857.
Economics - Overcrowding - Profit - Stocking density

An increase in stall stocking density (SSD), as measured by the number of lactating cows per stall in a freestall barn, reduces cow performance, such as milk yield and fertility, but may increase farm profitability. Our objectives were to calculate effects of varying SSD on profit per stall for a range of effects on cow performances and external farm factors and store results in regression metamodels. The literature on quantified effects of SSD on cow performance that directly affects cash flow was found to be weak. We assumed effects of SSD on milk yield, probability of conception, and probability of culling. External farm factors were probability of insemination, feed price, and milk price. A herd budget-simulation model was used which mimics the performance of cows in a herd and calculates profit per stall per year and other results. The SSD varied from 100 (no overstocking) to 150% (severe overstocking) in steps of 10%. Sensitivity analyses for effects of SSD on cow performance and effects of external farm factors were performed. Three regression metamodels were developed. The first metamodel accurately predicted profitability at 100% SSD for all variations in the external farm factors. Optimal SSD varied from 100 to 150% SSD, depending on the combination of inputs, and was very sensitive to changes in the size of the milk loss and milk and feed prices. Average optimal SSD of all 2,187 combinations of inputs was 120% SSD and average maximum increase in profit was $99/stall per year. Of the 2,187 combinations of inputs, 18% were ascending (maximum increase in profit >150% SSD), 33% were descending (maximum profit at 100% SSD), and 50% had a maximum increase in profit between 100 and 150% SSD. The second metamodel accurately captured changes in profit for all combinations of biological and external inputs and SSD. A third metamodel captured breakeven daily milk losses which would result in the same profit as at 100% SSD given the same external farm factors. In conclusion, overstocking was profitable under plausible economic conditions in the United States. The 3 metamodels accurately captured the results for a wide range of values of the input variables. A tradeoff will occur between economically optimal SSD and animal welfare in some situations.

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