Spatial variability in commercial orange groves. Part 2: relating canopy geometry to soil attributes and historical yield

Precision Agriculture - Site-specific management strategies are usually dependant on the understanding of the underlying cause and effect relationships that occur at the within-field level. The...     

Comparative mast seed production in unmanaged and shelterwood white pine (Pinus strobus L.) stands in central Ontario

The effect of the seed cut of the uniform shelterwood silvicultural system on white pine seed production, seed characteristics, and seed viability during 2 mast seeding events was examined in operationally harvested second growth, white pine-dominated forest stands in central Ontario. Seed traps placed along transects in unmanaged and shelterwood stands in each of 3 blocks were used to monitor seed production in 2000 and 2006 (4 and 10 years after harvesting). During these 2 mast seed years between 386,000 and 2,730,600 seed ha^?1 were produced among study stands. Total seed production expressed on a per hectare and unit pine basal area basis did not differ by harvest treatment or among blocks in either year. Variability in seed production among stands was primarily due to differences in stand structure, with seed production positively related to white pine basal area. Seed characteristics were largely similar between harvested and unmanaged stands and between seed years. Seed viability was relatively high in both years, with seed from shelterwoods germinating slightly slower than those from unmanaged stands. Seed quality, as estimated by laboratory germination performance, was higher in 2006 than 2000, likely due to improved seed development and maturation in the warmer, wetter growing season of 2006. Our results suggest that the seed cut of the uniform shelterwood system applied to second growth white pine stands is unlikely to adversely affect white pine seed production, seed quality, or potential for natural regeneration during mast seeding events.     

Accumulation and depletion kinetics of erythromycin in rainbow trout (Oncorhynchus mykiss)

Erythromycin is an antimicrobial agent recommended for the control and treatment of diseases caused by gram-positive bacteria. Few studies, however, have determined the metabolic and pharmacokinetic aspects of this antimicrobial agent in fish. The aim of the present study, therefore, was to determine the accumulation and depletion time of erythromycin after administration of medicated feed containing 52 mg kg(-1) body weight day(-1) for 8 days in rainbow trout (Oncorhynchus mykiss). Results were analyzed following the European Agency for Evaluation of Medicinal Products guidelines. We measured a withdrawal time of 187°C-day (°C-day=water temperature×days), lower than the value (500°C-day) recommended by Council Directive 2004/28/EC for veterinary medicinal products. Our results provide data to establish therapeutic regimens for the use of erythromycin in aquaculture.     

Bioavailability of β-cryptoxanthin in the presence of phytosterols: in vitro and in vivo studies

Bioactive compounds are used in the design and development of new food products with potential health benefits, although little is known regarding their bioavailability and interactions. This study assessed the stability, in vitro bioaccessibility, and human bioavailability of β-cryptoxanthin from β-cryptoxanthin-rich drinks with and without added phytosterols developed for this purpose. The developed drinks showed no difference in the content of β-cryptoxanthin, and they were stable over 6 months. In vitro, hydrolysis of β-cryptoxanthin esters and the amount of free β-cryptoxanthin at duodenal and micellar phases were similar regardless of the presence of phytosterols. In the human study, the daily intake provoked significant increments of β-cryptoxanthin in serum regardless of the type of the drink. In conclusion, in vitro and in vivo human studies have shown that the bioavailability of β-cryptoxanthin is not significantly affected by the presence of phytosterols when they are simultaneously supplied in a drink.     

Brain anatomy of two-toed sloth (Choloepus didactylus,Linnaeus, 1758): A comparative gross anatomical study of extant xenarthrans

The neural system plays an important role in understanding some features of animals. Anatomical complexity correlates with the increase of functional capacity. Xenarthrans include anteaters (Vermilingua), armadillos (Cingulata) and sloths (Folivora). This group is the base of eutherian mammals, and understanding the anatomy of its neural system could provide data for functional and evolutionary interpretations. The gross anatomy of the xenarthran brain is recorded. Four extant families of Pilosa and two families of Cingulata were sampled. Usual dissection procedures were used, and the brains were analysed macroscopically. The brain of two-toed sloth, three-toed sloth, six-banded armadillo, giant anteater and collared anteater are gyrencephalic. Pygmy anteater, nine-banded armadillo, great long-nosed armadillo, southern naked-tailed armadillo and giant armadillo are lissencephalic. In most species, the rhinal fissure presents two segments, rostral and caudal (except in Vermilingua and three-toed sloth). The diencephalon and brainstem present similar anatomy. The cerebellum is wide and presents four lobes (rostral, central, caudal and floccular). Its average volume is 12.16% (Folivora), 14.26% (Vermilingua) and 18.61% (Cingulata). Among these groups, there is a statistical difference between Folivora/Cingulata concerning the cerebellum average. The general pattern of the brain of the xenarthrans is similar to that of other mammals.     

The Damara in the context of Southern Africa fat-tailed sheep breeds

Sheep production is one of the most important activities in animal production in tropical regions. Southern Africa (SA) fat-tailed sheep such as the Afrikaner, Namaqua Afrikaner, Nguni, Persian Black Head, Tswana, Pedi, Sabi, and particularly the Damara are important animal genetic resources very well adapted to their harsh home environments. In this review, autochthonous sheep genetic resources of SA are reviewed regarding history and productive performance. A special focus is made to the most internationalized of such breeds: the Damara. The following aspects are reviewed: history, standards, productive performance in SA, and importation to Australia. Finally, a reference is made to the influence of fat-tailed sheep formation of composite breeds such as the Dorper or the Meatmaster.     

Evaluation of endotoxaemia in the prognosis and treatment of scouring merino lambs

This study looked at measurement of endotoxaemia as a tool in determining prognosis and probable response to treatment in scouring lambs. One hundred eighty-three lambs in the first 15-20 days of life, from eight Merino sheep farms located in the region of La Serena, south-west Spain, were used in this experiment. Scouring and normal/control lambs were selected following a clinical examination, the scouring group was further divided into subgroups, specifically those that did or did not survive 72 h following treatment. At the time of the clinical examination, faecal and blood samples were taken. Faecal culture and commercial faecal antigen tests for detection of enteropathogens in faeces and serum endotoxin measurement using chromogenic lymulus amoebocyte lysate (LAL) were carried out. Scouring lambs received 0.07 mg/kg liveweight halofuginone once a day for 3 days, a single oral dose of 0.20 mg/kg liveweight of spectinomycin and oral rehydration fluid. The pathogens isolated were Cryptosporidium spp. and Escherichia coli. The case fatality rate was 51% in the scouring lambs. Postmortem findings were consistent with enterotoxigenic E. coli infection. The concentration of endotoxin was 0.18 +/- 0.12 ng/ml in the control group, 0.35 +/- 0.17 ng/ml in the surviving lambs and 0.46 +/- 0.14 ng/ml in the non-surviving lambs. Significant differences between groups were found. Case fatality rate of the scouring lambs with endotoxaemia below 0.30 ng/ml was 0%, while it was 100% above 0.50 ng/ml. These results may be utilized as a prognostic indicator in lambs affected by E. coli and Cryptosporidium that will help aid in decision-making as to whether to treat a lamb or not based on its chances of survival.     

A retrospective study of 29 cases of otitis media/interna in dairy calves

Epidemiological data, clinical findings, laboratory data, medical imaging, and outcomes were reviewed in 29 dairy calves with otitis media/interna. Age at admission ranged from 1 to 24 wk. The majority of calves were referred during winter. Clinical signs included drooping ear, ptosis, head tilt, abnormal nystagmus, strabismus, dysphagia, regurgitation, stiff neck, opisthotonos, facial hyperesthesia, and purulent aural discharge. Intranasal endoscopic examination of 5 animals revealed nasopharyngeal collapse in 4. Cerebrospinal fluid (CSF) was abnormal in all of 7 cases. Mycoplasma bovis was cultured from all but 1 case with external ear or tympanic bullae samples (n = 12), and Mycoplasma arginini was cultured from the remaining ear sample. Radiographs of the tympanic bullae were performed in 24 calves, tomodensitometry (CT) in 3 calves and ultrasound in 4 calves. According to medical imaging techniques or necropsy, 69% of the cases were classified as chronic. Mean duration of treatment was 23.3 d. The rate of clinical recovery was 75%.     

A pre-synchronization program at early postpartum might increase the chances of Bos indicus cows cycling prior to 50 days regardless of the length of calf separation

The aim of this study was to establish if pre-synchronization would enhance the number of animals cycling prior to conventional breeding at 45 days irrespective of the length of calf separation. Multiparous Bos indicus cows were allotted in four groups (n = 10). Control group (C) dams remained with their calves; groups G24, G48 and G72, which were partially weaned for 24, 48 and 72 h, respectively, were estrus synchronized using a controlled internal drug. These procedures were performed at 25 days and again at 45 days postpartum. The number of follicles, presence of a corpus luteum and back fat thickness (BFT) were determined by ultrasound. The proportion of cows with estrus and ovulation at day 25 postpartum was statistically different between the control and treated groups, with the values being 20, 60, 50 and 70 for the control, G24, G48 and G72 groups respectively (P < 0.05). At days 45 postpartum, the proportion of cows with estrus and ovulation was different in group G48 compared with the other groups (P <0.05). The average BFT and body condition score for the four experimental groups in the two periods were similar (P >0.05). Animals with a higher proportion of follicles from 17 to 21 mm, BFT values above 3.5 mm and a regular body condition were significantly different regardless of whether the dams remained with their calves or were separated, regardless of the length of this event. It can be concluded that (1) a pre-synchronization program at day 25 could trigger the onset of ovarian activity and facilitate a breeding program at day 50 and (2) temporary weaning enhances the effect of a pre-synchronization program.     

Revue des pratiques d'elevage de poissons en cages dans les eaux continentalesA review of fish cage culture as practised in inland waters

The rearing of fish in cages could greatly contribute to increasing fish production in existing inland waters. Although it presents numerous advantages, its limitations and possible inconveniences must be borne in mind. Well-developed technology is available mainly from the Democratic Republic of Germany, The Netherlands, Japan, the U.S.A., the U.S.S.R. and the Lower Mekong region. Research is currently pursued in numerous other countries, where the use of floating cages in fish culture is becoming increasingly diversified.The most popular fish species used in intensive cultural systems are Cyprinus carpio, Ictalurus punctatus and Salmo gairdneri. In the semi-intensive Asian systems, Barbus spp., Pangasius spp. and murrels are among the favourite cage-reared fishes. Tilapia aurea and Tilapia nilotica have also proved to be well adapted to cage culture. Polyculture is only rarely practised.Floating cages seem to be the best suited for fish culture in most cases. Net cages are the simplest in design and the cheapest to build. The escape of fish, however, always remains an eventuality which might lead to choosing more expensive designs. Maintenance of cages must be regular. For flexibility of exploitation, cages should not be too large. Their location within the water body can play an important role in keeping production high.At high stocking rates, artificial feeding of a well-adapted diet is a necessity. Optimum conversion rates require a well-adjusted daily ration, possibly fractioned. Mechanized feed distribution is to be encouraged as a labour-saving practice. Less intensive systems rely more on locally available wastes, such as trash fish, but the feeding rate then depends mostly on feed prices.Best growth is generally achieved by C. carpio and I. punctatus. Attainable maximum production is as high as 35 kg/m³/month under intensive management. However, generally, production averages from 5 to 30 kg/m³/month for these two species. S. gairdneri is less productive. T. aurea and T. nilotica have both a very good potential. Production in less intensive systems varies greatly according to management practices.