Increasing Stocking Density Research Articles

Effect of stocking density on growth performance, serum biochemical parameters, and muscle texture properties of genetically improved farm tilapia, Oreochromis niloticus

The objective of this study was to assess the effects of stocking density on growth performance, serum biochemical parameters, and muscle texture properties of genetically improved farmed tilapia (Oreochromis niloticus, GIFT). Juvenile GIFT with an average initial weight of 12.54 ± 0.45 g (mean ± SD) were randomly stocked in 16 tanks (80 L) in a recirculation aquaculture system at four densities of 10 (D1), 20 (D2), 30 (D3), and 40 (D4) fish per tank for 56 days, with quadruplicate for each density. There were no significant differences in water temperature among the four treatments (P > 0.05). D4 had the significantly lowest dissolved oxygen content (5.52 vs 5.69–6.09 mg L−1) (P > 0.05) and pH (6.63 vs 6.87–7.20) (P < 0.05). NO2-N and NH4-N concentrations significantly increased with increasing stocking density (P < 0.05). Weight gain (WG) and specific growth rates (SGR) decreased with increasing stocking density. The lowest WG (617.20 vs 660.45–747.06%), SGR (3.52 vs 3.62–3.81% day−1), and highest feed conversion ratio (1.68 vs 1.53–1.58) were observed in D4. Fish at D4 had significantly lower condition factor (3.11 vs 3.29–3.37%) and survival rate (91.25 vs 97.50%) than those from D1 and D2 (P < 0.05). With increasing stocking density, serum total cholesterol, triglyceride, and total protein concentrations decreased (P < 0.05) and aspartate aminotransferase and alanine aminotransferase activities increased (P < 0.05). D4 fish had higher moisture content (78.80 vs 76.97%) and lower crude protein content (18.14 vs 19.39%) in muscle than D1 fish (P < 0.05). Compared to D1 and D2, D3 and D4 had lower muscle hardness (1271.54–1294.07 vs 1465.12–1485.65 g), springiness (0.62–0.65 vs 0.70–0.72), gumminess (857.33–885.32 vs 1058.82–1079.28 g), and chewiness (533.04–577.09 vs 757.53–775.69 g) (P < 0.05). High stocking density resulted in growth inhibition, declines in flesh quality, and disturbance to several serum biochemical parameters.

Effect of Different Stocking Densities as an Environmental Stressing Factor on Broiler Behavior and Performance

Six hundreds of unsexed Arbor Acres chicks were used and housed in symmetrical 9 pens withthree levels of stocking12 bird/m2, 15 bird/m2 and 20 bird/m2. Productive performance parameterswere measured including, average daily Feed intake, average body weight, average weekly weightgain, feed conversion rate (FCR), mortality rate, dressing yield and visceral organs weight.Behavioral observations including feeding, drinking, leg scratching, leg -wing stretching, preening,litter eating and dust bathing were done by scan sampling, birds were observed 3 days /week.Results revealed that the growth performance within the first and second weeks, the high stockingdensity group (20 bird/m2) showed a high feed intake, body weight and body weight gain, followedby medium stocking density group (15 bird / m2) and the lowest performance parameters throughthe first two weeks were recorded in the control group. From the fourth to the fifth weeks, mediumdensity group (15 bird / m2) showed a higher feed intake body weight and body weight gain. Themoderate stocking density achieved a higher final body weight was 1954 ±1.73 g, body weight gain1911.75 ±1.73 g, also feed intake passed in the same direction MSD consumed 3117.19 ±11.4 g/bird. Finally, all group showing the same feed conversion ratio as all different stocking densitiesshowing no significant differences in FCR. The results carcass characteristics showed that themoderate stocking density group (15 bird/ m2) achieve the highest dressing weight and higherdressing percentage compared with other two groups. Regarding to internal organ weight thecontrol group showed the highest gizzard, liver, and heart weights followed by moderate and highstocking density group respectively. the results clearly showed that increasing SD significantlyreduced the weights of the lymphoid organs. Behavioral Indicators showed that within the first twoweeks, the feeding and drinking behavior was significantly differ, as the moderate and high densitygroups showing the higher feeding than control group. The final feeding and drinking behaviorwithin the whole experimental period, there was no statistical significant difference between thedifferent groups. The welfare behavior indicators, including leg and wing stretch, leg scratch,preening and resting behavior were recorded within five weeks and also from total means for allgroup it was clear that from the first week till the end of experiment the stocking density negatively correlated to the welfare behavior indicators. Regarding to resting behavior within weeks and in allover means in the different groups although there was no significant difference between different groups as p > 0.05 there was a decrease in the resting behavior percentage with increased stocking density.

Effects of sex and stocking density on the performance of broiler chickens in a sub-tropical environment

The current study investigated the effects of sex and stocking density and their interaction on growth performance and carcass characteristics of broiler chickens in a semi-arid sub-tropical environment. A total of 1008 day-old Cobb Avian48 chicks, namely 462 males and 546 females, were reared at final stocking densities of 30, 35, and 40 kg bodyweight per square metre (BW/m2) corresponding to 44, 51 and 59, and 52, 61 and 69 chicks per pen for males and females, respectively, during a 42-day production period. The experiment was a 2 × 3 factorial completely randomized design, with each sex-stocking density combination being replicated three times. After the initial weighing, the birds were weighed individually [grams (g)] each week until the 42nd day. At day 42, four birds from each pen were randomly sampled and slaughtered, and carcass characteristics were measured after 48 hours, and expressed as percentages of bodyweight. Growth performance and carcass characteristic parameters were subjected to analysis of variance using the general linear model procedures of Minitab statistical software version 17. Treatment means were compared using Tukey’s test (at α = 0.05). Males gained more weight and were significantly heavier at slaughter age (2649 ± 43.1 g) than females (2270 ± 43.1 g). There was a progressive reduction in feed intake with increasing stocking density, but neither sex nor stocking density influenced feed conversion ratio and mortality rate. Sex significantly affected dressing percentage and carcass parts percentages, namely breast, neck, shank, heart and abdominal fat and thigh, liver and gizzard. On the other hand, stocking density significantly influenced dressing percentage and carcass parts percentages such as breast, thigh, drumstick, neck, shank, liver and gizzard. There was a significant sex x stocking density interaction effect on percentages of thigh and liver. It is therefore suggested that for efficient 42-day production cycles of broilers in the subtropics, Cobb Avian48 males reared at the stocking density of 40 kg BW/m2 could be considered the best option.Keywords: Carcass characteristics, Cobb Avian48, feed conversion ratio, mortality

A pilot study into biomass yield and composition under increased stocking rates and increased stocking densities on a Namibian organic beef cattle and sheep farm

Sustainable rangeland management is crucial for conservation and improvement of global grassland ecosystems, livestock performance and grassland-linked livelihoods. This applies in particular for Sub-Saharan African countries like Namibia with its rangeland-based low external input livestock husbandry. In the local savannas, productivity and resource distribution is spatially heterogeneous and temporally variable, which calls for adaptive and responsive grazing strategies to meet the needs of livestock and vegetation. The adjustment of stocking rate (SR; kilogramme livestock per hectare per year) and stocking density (SD; kilogramme livestock per hectare during a specific grazing event) is considered as a key success factor but very different rates and densities have been recommended in the past by practitioners, scientific evidence is lacking. On an Organic Namibian beef cattle and sheep farm were these recommendations assessed in order to investigate the responses of savanna rangelands to varying grazing intensities. Since 2014, forage biomass production and composition under three different grazing regimes have been assessed: (1) the routine management (here Holistic Management) as control and in comparison to this (2) an increased SR or (3) increased SD. Destructive biomass sampling was done each May in 2014, 2015, 2016 and 2017, respectively. The results showed that the increased SR or SD can be beneficial for average fodder production, but not significantly. However, the negative standing dead biomass accumulation was significantly reduced.

High stocking density alters growth performance, blood biochemistry, intestinal histology, and muscle quality of channel catfish Ictalurus punctatus

Stocking density is one of the major factors affecting production and welfare of fish in aquaculture. This study investigated the effect of different stocking densities on growth, feed efficiency, blood biochemistry, histometric response, muscular composition, and flesh quality of channel catfish Ictalurus punctatus. Fish were cultured at low, medium, and high stocking density of 50, 150, and 300 fish m−3, respectively, for 60 days in the recirculating aquaculture system. Fish growth and feed efficiency significantly decreased with increasing stocking density. Serum concentrations of glucose, triglyceride, and total cholesterol, as well as the activities of both aspartate aminotransferase and alanine aminotransferase, significantly elevated as stocking density increased. High stocking density led to the decline in serum levels of thyroid hormones. The villi length and its number, as well as the size of goblet cells in the intestine, were negatively affected by high stocking density. There was a significant density-dependent decrease in muscular fat content, diameter of dorsal muscle fiber, intensity of muscular bundles, and percentage of muscular bundles area in dorsal muscle. However, the percentage of the intramuscular connective tissue showed a significant increase in fish reared at high stocking density. Fish stocked in high density exhibited the decrease in muscle pH, drip loss, and frozen leakage rate. Overall, the increased stocking density could cause the unfavorable impacts on growth, feed efficiency, histological change, and flesh quality of I. punctatus.

Effects of fumonisin B1 and mycotoxin binders on growth performance, tibia characteristics, gut physiology, and stress indicators in broiler chickens raised in different stocking densities

The present study was carried out to investigate the effects of stocking density, fumonisin B1 (FB), and mycotoxin binder (TB) on growth performance, bone quality, physiological stress indicators, and gut health in broiler chickens. Day-old Ross 308 male broiler chicks (n = 1,440/experiment) were randomly allocated to 72 floor pens in a 3 × 2 × 2 factorial arrangement, using 3 stocking densities (12.5 birds/m2 [HSD], 10 birds/m2 [MSD], or 7.5 birds/m2 [LSD]), 2 levels of purified FB (0 or 10ppm), and 2 levels of TB (0 or 0.2%). Each treatment had 6 replicates (n = 6/treatment) and experiments lasted 34 days. All data were analyzed using 3-way ANOVA with stocking density level, FB, and TB as main factors. Body weight gain and feed intake were lower (P <0.05) in broilers kept at HSD and MSD compared to LSD-housed counterparts. Birds fed an FB-contaminated diet exhibited a higher feed-to-gain ratio compared with those fed an FB-free diet (P <0.05). None of the treatments affected intestinal morphology or ileal secretory immunoglobulin A levels. Stocking density affected tibia breaking strength (P <0.05), which was lower in chickens housed at HSD compared with LSD-housed chickens. The heterophil/lymphocyte ratio (H/L ratio) was elevated (P <0.05) in HSD and MSD groups compared with the LSD group. Serum nitric oxide (NO) levels were elevated (P <0.05) in chickens fed the FB-contaminated diet compared with the control diet-fed counterparts. Significant interaction (P <0.05) between FB and TB on serum NO levels was noted. In summary, increasing stocking density lowered growth performance and bone quality, but increased the H/L ratio. Dietary TB did not affect FB-induced increases in the feed-to-gain ratio. No interaction was observed between stocking density and FB for the measured variables.

Effects of inorganic carbon supplies and light on photosynthetic functions of Pyropia haitanensis.

The increasing stocking density of algal often results in lowered carbon and light levels. In this study, Pyropia haitanensis were cultured under four different conditions, i.e., 390 μL·L-1 (ambient carbon supply) + ambient sunlight, 20 μL·L-1(decreased carbon supply) + ambient sunlight, 390 μL·L-1 + decreased sunlight (20% of ambient sunlight), 20 μL·L-1 + decreased sunlight. The activity of carbonic anhydrase (CA), photosynthetic rate and quantum efficiency of open photosynthetic system 2 (Fv'/Fm') of the algae under different temperatures were measured to investigate the effects of decreased carbon supply and lowered light on photosynthetic functions of P. haitanensis. The results showed the CA activities of the algae at decreased carbon supply and lowered sunlight was increased. The maximum Ci-saturated photosynthetic rates (Vmax) were elevated under the low sunlight compared with that under the ambient sunlight. The Vmax of the algae at low carbon seawater was lower than that at ambient carbon seawater under lowered sunlight. Under ambient sunlight, the Vmax of the decreased carbon-grown algae was higher than that of ambient carbon-grown algae. The Fv'/Fm' values of the algae grown at lowered carbon supply and decreased sunlight conditions showed no variation at low temperature (10 ℃) and high temperature (30 ℃), whereas it was decreased by about 76.4% when cultured at 390 μL·L-1 + ambient sunlight at 200 min than that at 40 min under 30 ℃. These results suggested that decreased carbon supply and lowered sunlight intensity would improve in the capacity of HCO3- utilization and resistance to short-term temperature change in P. haitaneisis. The effects of low carbon on photosynthetic rate of the algae were dependent on light context.

Effect of Stocking Density on Growth Performance, Production Trait, Food Utilization and Body Composition, of Meagre (Argyrosomus regius)

A 10-week rearing trial was conducted in cages with average initial weight of 9.15 ± 0.2 g/fish and average initial length of 9.2 ± 0.02 cm/fish of meagre, Argyrosomus regius, to examine the effect of three stocking density on growth performances, production traits, feed utilization and body composition. Nine cages 24 m3 each (4 × 6 × 1.5 m, long, width and height) were stocked with either 1200, 3600 and 6000 fish for each cage to give a stocking rate of 50, 150, and 250 fish/m3 respectively and fish fed daily, slightly in excess of satiation to eliminate the possibility of food supply being a limiting factor to growth. The results revealed that, mean final weight (g/fish), gain in weight, SGR (%per day), feed conversion ratio, protein efficiency ratio and total feed intake (g/fish) were significantly (P ≤ 0.01) influenced. The best at the lowest stocking density, while, the total production and net production exhibited significantly the opposite trend. Harvest and production estimates increased with increasing stocking density. Fish body composition% of moisture, protein, fat and ash were significantly (P ≤ 0.01) influenced by stocking density. From the above results and the economic information of the study, it can be concluded that stocking density of 50 fish/m3 of meagre exhibited the highest net profit and would seem to be the most desirable density in the system studied.

Risk factors associated with tilapia and pangasius diseases

Tilapia (Oreochromis niloticus) and pangasius (Pangasianodon hypophthalmus) are currently very important and popular species for aquaculture inBangladesh. They are cultured commercially in high stocking densities which are accompanied by several risk factors leading to disease outbreaks. The present study was carried out to investigate diseases of these two species under farming condition with special emphasis on risk factors analysis and their health management strategies. Data were collected through questionnaire interview and focus group discussion with farmers. Altogether 50 farmers were interviewed of which 25 were tilapia farmers and 25 were pangus farmers in Trishal upazila of Mymensingh district. Possible risks were assessed using certain parameters like season of disease occurrence, presence of predators in farms, contact with livestock, maintenance of farm hygiene, sharing of farming tools, feeding of fish and pond management measures. It was found that presence of predatory birds, maintenance of good farm hygiene, sharing of tools, increased stocking densities and improper pond management were the major risks of disease outbreak. The most prevalent clinical signs of diseased fish included anal protrusion and red spot on body surface in case of pangus while pop and red eye and gas problems were common in both pangasius and tilapia. Generally, pangus were found more susceptible to disease than tilapia. Predatory birds were a big problem in the study area. They act as a potential carrier of infectious organisms among farms from farm to farm.J. Bangladesh Agril. Univ. 15(2): 325-331, December 2017

Effect of stocking density on growth performance, digestive enzyme activities, and nonspecific immune parameters of Palaemonetes sinensis

Palaemonetes sinensis is a new breed of shrimp with great potential for aquaculture, which has been confirmed in our previous production tests. However, there are limited reports about this species and its biological information is scarce. This study describes the effect of stocking density on the growth, digestive enzyme activities, and nonspecific immunity of P. sinensis with an initial average body weight was 0.25 ± 0.02 g. Groups of shrimps were reared at four different initial densities (2.5, 5, 10, and 20 individuals·L−1). After 30 days of culture, the results indicated that the final body weight, weight gain, and specific growth rate were higher in shrimps grown in groups of 10 individuals·L−1 than other groups, but the survival rates of these shrimp were significantly lower than those reared in group of 2.5 or 5 individuals·L−1. The trypsin, amylase, and lipase activities of shrimp significantly decreased with increase in stocking density. Nonspecific immune indicators decreased significantly with increase in density, but there were no significant differences between the 2.5 and 5 individuals·L−1 groups in terms of the total haemocyte count (THC), phenoloxidase activity (PO), lysozyme (LZM), catalase (CAT), and superoxide dismutase (SOD). These results suggest that increasing the stocking density from 2.5 to 5 individuals·L−1 did not affect any of the detected indicators of P. sinensis, but there are shelter in farming mode is better for culture of P. sinensis up to 10 individuals L−1.

Yield gap analysis of feed-crop livestock systems: The case of grass-based beef production in France

Sustainable intensification is a strategy contributing to global food security. The scope for sustainable intensification in crop sciences can be assessed through yield gap analysis, using crop growth models based on concepts of production ecology. Recently, an analogous cattle production model named LiGAPS-Beef (Livestock simulator for Generic analysis of Animal Production Systems – Beef cattle) was developed, which allows yield gap analysis in beef production systems. This paper is the first to assess yield gaps of integrated feed-crop livestock systems, to analyse underlying causes of yield gaps, and to identify feasible improvement options. We used grass-based beef production in the Charolais area of France as a case study. To this end, we combined LiGAPS-Beef with crop growth models that simulate grass production (fresh grass under grazing, grass silage, hay) and wheat production (concentrate). Feed crop and cattle production were integrated to simulate potential and resource-limited live weight (LW) production per hectare. Potential production is defined as the theoretical maximum LW production per ha, in the absence of resource or management limitations. Resource-limited production is determined by availability of one or several resources: water and nutrients for crops, and feed quality and quantity for animals. Potential production of a cattle herd with an ad libitum diet of grass silage was 2380kgLWha−1year−1 and resource-limited production was 664kgLWha−1year−1. Actual LW production (354kgLWha−1year−1) was 15% of the potential production, implying a relative yield gap of 85%, and 53% of the resource-limited production, implying a relative yield gap of 47%. Applying yield gap analysis disentangled the major biophysical causes of these yield gaps: feeding diets other than the ad libitum grass silage diet, water-limitation in feed crops, and sub-optimal management. These yield gaps suggest scope to intensify beef production. We demonstrate, however, that yield gap mitigation decreased the operational profit per kg LW under the European regulations for bovine and grassland premiums operational in 2014. Hence, as expected, the premiums aiming to support farmers' income and to promote sustainable agriculture and rural development were not conducive to narrow yield gaps at the same time. The current common agricultural policy (CAP, 2015–2020) provides more scope for intensification, such as increasing stocking density via better grassland management.

Beneficial effects of fish stocking on performance and pest control in the lotus field system

AEI Aquaculture Environment Interactions Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections AEI 9:321-329 (2017) - DOI: https://doi.org/10.3354/aei00237 Beneficial effects of fish stocking on performance and pest control in the lotus field system Li Ma1, Jie Zhu1, Qi Chen1, Wei Li2,*, Guo-Hua Huang1,* 1Hunan Provincial Key Laboratory for Biology and Control of Plant Diseases and Insect Pests, Hunan Agricultural University, Changsha 410128, Hunan, PR China 2State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, Hubei, PR China *Corresponding authors: liwei@ihb.ac.cn; ghhuang@hunau.edu.cn ABSTRACT: The present study was conducted to evaluate the economic effects of fish stocking on plant and fish performance in lotus fields, as well as to determine its influence on controlling common pest species associated with lotus fields. Lotus yield, fish growth performance, economic returns and pest abundance at 5 fish stocking density treatments (0, 1500, 3000, 4500 and 6000 ind. ha-1) were determined in 15 separate lotus fields at a lotus farming facility in Wugang City, Hunan Province, China. The results showed a tendency for the lotus yield to increase with fish stocking density, but significant differences were not found among the treatments. Survival rates were not significantly different among the fish stocking treatments for the 3 species of carp tested. Absolute growth rate and specific growth rate showed similar trends, with their values significantly decreasing as stocking density increased for each carp species. The total yield for the 3 fish species did show significant differences, with the highest yield in the 6000 treatment and the lowest in the 1500 treatment. Total net income was highest in the 4500 treatment and lowest in the control (0) treatment. No significant differences were observed between the 4500 and 3000 treatments. The abundance levels of 3 types of pests were lower in the fish stocking treatments than in the control treatment, and were shown to decrease with increasing stocking density. Based on these observations, stocking densities of 3000 to 4200 total ind. ha-1 were considered optimal levels in lotus-fish culture systems. KEY WORDS: Growth efficiency · Lotus-fish culture · Nelumbo nucifera · Carps · Stocking density · Performance · Economic benefit · Pest control Full text in pdf format PreviousNextCite this article as: Ma L, Zhu J, Chen Q, Li W, Huang GH (2017) Beneficial effects of fish stocking on performance and pest control in the lotus field system. Aquacult Environ Interact 9:321-329. https://doi.org/10.3354/aei00237 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in AEI Vol. 9. Online publication date: September 05, 2017 Print ISSN: 1869-215X; Online ISSN: 1869-7534 Copyright © 2017 Inter-Research.

Effect of stocking density on performance, diet selection, total-tract digestion, and nitrogen balance among heifers grazing cool-season annual forages.

Grazing annual cool-season forages after oat grain harvest in South Dakota may allow an opportunity to increase efficient use of tillable land. However, data are limited regarding effects of stocking density on diet selection, nutrient digestion, performance, and N retention by cattle grazing annual cool-season forage. Heifers were blocked by initial BW (261 ± 11.7 kg) and randomly assigned to 1 of 12 paddocks (1.1 ha) to graze a mixture of grass and brassica for 48 d. Each paddock contained 3, 4, or 5 heifers to achieve 4 replicates of each stocking density treatment. Ruminally cannulated heifers were used to measure diet and nutrient intake. Effects of stocking density on diet and nutrient selection were measured after 2, 24, and 46 d of grazing, and BW was measured at the beginning, middle, and end of the experiment as the average of d 1 and 2, d 22 and 23, and d 47 and 48 BW, respectively. Measures of DMI and DM, OM, NDF, and ADF digestion were collected from d 18 to 23. Increased stocking density increased intake of brassica relative to grass on d 24 (quadratic, = 0.02), but increased stocking density decreased (linear, ≤ 0.01) intake of brassica compared with grass on d 48 (stocking density × time, < 0.01). Increased stocking density increased DM (quadratic, < 0.01), OM (quadratic, = 0.01), and NDF (quadratic, = 0.05) digestion, and stocking density tended to increase DMI (quadratic, = 0.07). Additionally, increased stocking density quadratically increased ( = 0.05) N retention but did not affect overall BW gains. Increased stocking density did, however, contribute to linearly decreased ( = 0.05) BW gains from d 1 to 22 of grazing, but BW gains during the latter half of the experiment were greater than BW gains from d 1 to 22. Ruminal concentration of acetate:propionate was least on d 24 of grazing, and ruminal nitrate concentration tended to linearly decrease ( = 0.06) with greater amounts of time on pasture. Ruminal liquid and particulate fill and amounts of VFA were less (quadratic, ≤ 0.01) with greater amounts of time on pasture. Apparently, binary mixtures of brassica and grass planted after oat grain harvest can provide an opportunity to increase efficient use of land by providing forage resources. Increased stocking density may facilitate a more rapid adaptation to and intake of brassica among cattle grazing brassica-grass-based pastures.

Resource use efficiency of broiler production in tunnel-ventilated environmental control vis-à-vis open-sided conventional shed during summer.

Present study was conducted to assess the resource use efficiency of broilers production, in tunnel-ventilated environment control (ECBH) and open-sided conventional (OSCBH) house under different stocking densities. Different treatments comprised of T 0 (birds with floor space, 1.0/ft2/bird in open-sided conventional broiler house (OSCBH) as control, while different treatments in tunnel-ventilated environment control broiler house (ECBH) were T 1, T 2, T 3, T 4 and T 5 with floor space of 1.0, 0.9, 0.8, 0.7and 0.6 ft2 per bird, respectively. The results of shed microclimate indicated that shed temperature and temperature humidity index (THI) at 12:00 and 15:00 IST and maximum and minimum temperature in OSCBH were significantly (p ≤ 0.05) higher than ECBH. Litter moisture and pH did not differ significantly and were within permissible limits in both OSCBH and ECBH. Final body weight, body weight gain, feed intake were significantly higher and FCR, PER and EER were significantly better in ECBH than OSCBH (T 0) even at 10% increase in stocking density (T 2). Margin of receipt in T 2 in ECBH from sale of live bird/unit area and kilogram live weight per unit area was maximum which was Rs. 5.08/- and 3.56/- higher than T 0 for OSCBH.

Spatial and Temporal Grazing Patterns on Intensive‐early Stocked and Season‐long Stocked Pastures

Core Ideas Temporal grazing patterns influence forage quality. Temporal and spatial grazing patterns aid in grazing system design. Uniformity of grazing distribution is enhanced by increased stocking density. Spatial and temporal patterns of domestic cattle (Bos taurus × Bos indicus) grazing were observed over two consecutive years under two grazing systems, intensive‐early stocking (IES) and season‐long stocking (SLS), to determine the factors influencing the observed patterns. Temporal grazing patterns differed between the two grazing treatments. Area grazed and forage height reduction remained relatively stable and consistently higher on IES pastures than on SLS pastures until midseason. In contrast, SLS pastures exhibited steady increases in area grazed and forage height reduction throughout the grazing season and was comparable to IES by the end of the grazing season. Percent forage height reduction was significantly higher on IES pastures than on SLS pastures in both years until midseason when the IES steers were removed. There was no difference between the amounts of forage height reduction at the end of grazing trials in SLS pastures compared with overall IES means. Cattle grazed a higher percentage of pasture area on IES pastures than SLS in both years. Grazing intensity did not differ between treatments but was significantly different between years. The IES pastures were more uniformly grazed than SLS pastures during the period when both treatments were present, but there was no difference when overall pasture means were compared. Big bluestem (Andropogon gerardii Vitman) tillers were grazed more frequently under IES than under SLS. The results indicate that temporal grazing patterns should be considered when evaluating the performance and design of grazing systems since spatial patterns alone may not reveal periods when forage quality or plant physiology may be adversely or positively affected.

Survival, growth and physiological responses of juvenile Japanese flounder (Paralichthys olivaceus, Temminck &amp; Schlegel, 1846) exposed to different dissolved oxygen concentrations and stocking densities

The aim of this study was to determine to what extent juvenile Japanese flounder can adapt to different stocking densities in captivity and to examine whether growth and some physiological parameters critical for welfare might be affected by different dissolved oxygen levels. Japanese flounder (Paralichthys olivaceus) juveniles (initial weight 1.27 ± 0.04 g/fish) were reared at five stocking densities (500, 1,000, 1,500, 2,000, 2,500 ind/m3) and two levels of dissolved oxygen (DO) concentration (5.5 ± 0.5 mg/L or 14 ± 2 mg/L) with duplicate tanks for each treatment in water-recirculating systems for 40 days. Survival and activity of superoxide dismutase (SOD) were not affected either by stocking density or dissolved oxygen, whereas final body weight, specific growth rate (SGR) and feed conversion efficiency (FCE) of fish under low DO concentration decreased significantly with increasing stocking density. In contrast, growth of fish reared in high DO levels were unaffected by the stocking density. Furthermore, fish in this group had a higher feed intake and, consequently, grew faster (SGR) and achieved a higher final weight than fish reared at the low DO level. A significant reduction in hemoglobin (Hb) concentration and red blood cell (RBC) count of fish were recorded as DO concentration increased. Furthermore, the activity of protease decreased significantly with increasing stocking density and increased significantly with increasing DO concentration. The ventilation frequency results indicate that gill ventilation decreased significantly as DO levels increased. This study demonstrates that stocking density can affect the growth performance and physiological parameters critical for welfare of juvenile Japanese flounder. Also shown is that pure oxygen supplementation is an effective way to improve the growth of juvenile Japanese flounder when reared at a high stocking density.

Control of ectoparasites in the breeding bitch and queen

Parasite control in cats and dogs is important, not only to improve animal health but also to reduce zoonotic risk. The likelihood of parasitic disease and zoonotic transmission may be influenced by immunological changes in individual animals and by increased stocking density and proximity. The breeding environment for bitches, queens and their litters represents a situation where optimal conditions for parasites may be present in combination, therefore special consideration needs to be taken in their control. This article considers the treatment and control of fleas, mites and lice, and considers factors that may present particular problems in the breeding environment.

Seeding filamentous Ulva tepida on free-floating surfaces: A novel cultivation method

The selection of seaweed species for the integrated cultivation in land-based aquaculture systems is primarily based on the ability to grow in free-floating cultures thereby increasing stocking densities and areal biomass productivity. We assessed a novel approach to enable the free-floating cultivation of seaweed species that are dependent on the attachment to surface structures by seeding zoids of Ulva tepida onto small surfaces which float in the water column. In this study we firstly assessed how the density of settlement surfaces (hereafter referred to as ‘bioballs’) and density of zoids influenced the settlement onto bioballs, and secondly how the stocking density of these seeded bioballs affected the biomass yield in outdoor cultivation over a 35day period. Settlement was not affected by the density of bioballs with zoids settling evenly across bioball treatments. The number of zoids that settled successfully increased with increasing density. However, both seeding factors (density of bioballs and zoids) had a minimal effect on growth rates, yield of biomass per bioball and total biomass harvested, which were primarily affected by stocking density. Low stocking density generally resulted in higher growth rates and yield of biomass per bioball, although the total yield was lower compared to higher stocking densities. Overall, growth rates decreased over time for all stocking densities with a sharp decrease from 27days of outdoor cultivation and onwards due to reproductive events. Our study demonstrates that the rate of biomass production of U. tepida is primarily driven by the stocking density of seeded bioballs, and underlines the importance of short cultivation cycles with harvest prior to reproduction. This novel cultivation method enables the free-floating cultivation of species that normally depend on attachment to fixed surfaces and thereby expands the range of seaweed species for land-based cultivation.

Rearing of Freshwater Fish ‘Catla catla (Hamilton, 1822)’ Spawn to Fry in Green Water System with Harvested Rain Water in Cement Tanks

The present study on the effect of green water system with harvested rain water on growth performance of freshwater fish Catla catla. Spawn of Catla with an initial length 5.50±0.04 mm and weight 10.99±0.30 mg were stocked at the rate of 6, 8, 10 and 12 no.l-1 in cement tanks (2x1x1m). The green water system containing live phytoplankton viz., Chlorophyta, Cyanophyta and zooplankton viz., Rotifera, Cladocera, Copepoda and Protozoa were was used. The results of the study indicated that the maximum average length gain was (357.89±3.08%), weight gain (779.53±18.03%), specific growth rate (5.56±0.08%) and survival (45.20±0.13%) and were recorded significantly (P&lt;0.05) at stocking density of 6 spawn l-1 as compared to the other stocking densities. The growth of spawn to fry was observed to decrease with increase in the stocking density. Observations on the water quality revealed that the dissolved oxygen value decreased with an increased stocking density. Whereas, the value of ammonia-nitrogen, nitrite-nitrogen, and nitrate-nitrogen increased with the increase in the stocking density. The study showed that better growth and survival of Catla catla spawn to fry stage with stocking density of 6 spawn l-1 reared for a period of16 days in cement tank. The overall results of this study indicated that green water system with harvested rain water has a potential for rearing fish seeds.

Control of intestinal parasites in the breeding bitch and queen

Parasite control in cats and dogs is important, both to improve animal health and to reduce zoonotic risk. The likelihood of parasitic disease and zoonotic transmission may be influenced by immunological changes in individual animals and by increased stocking density and proximity. The breeding environment for bitches, queens and their litters represents a situation where optimal conditions for parasites may be present in combination, therefore special consideration needs to be taken in their control. This article considers the intestinal parasites that need to be considered in the breeding situation; their diagnosis and treatment; and general considerations in environmental parasite control.