Soilless Growing Media Amended With Sugarcane Filtercake Compost for Citrus Rootstock Production

Seeds of sour orange (Citrus aurantium L.) and Cleopatra mandarin (C. reticulata Blanco) were sown in Speedling trays filled with mixtures (v:v) of 0, 25, 50, 75 or 100 percent sugarcane filtercake compost (a natural waste by-product of sugarcane processing mills; bagasse) and a peat-lite medium. Seeds sown in 100 percent compost resulted in lower total percent germination, but similar mean days to emergence (MDE), seedling heights, and shoot weights and lower root weights than the control (100 percent peat-lite medium). Media amended with 25, 50 or 75 percent compost resulted in similar total percent emergence, (MDE) and root weights, but taller seedlings with heavier shoots than the control. SPAD-502 chlorophyll meter readings, and leaf N, Ca and Zn contents were higher for seedlings produced in compost amended media than in 100 percent peat-lite medium. The results suggest that compost derived from sugarcane filtercake can be successfully utilized as an amended medium for citrus seedling rootstock production.     

Effect of setting a maximum milking time,from peak lactation,on production,milking time and udder health

Abstract

AIM: To examine the effect of setting a maximum milking time, from peak lactation until drying-off, on production, duration of milking, and udder health of dairy cows.

METHODS: Forty cows were assigned in twin-pairs to be either milked until cups were removed at a milk flow-rate threshold of 0.35 kg/minute (Control), or until cups were removed at a milk flow-rate threshold of 0.35 kg/minute, or maximum time, whichever came first (MaxT). The maximum time was set by determining the milking time of the 70th percentile cow when ranked from fastest to slowest, irrespective of yield. The milking routine was typical of that practised on dairy farms in New Zealand, and involved no pre-milking preparation. The study began at peak lactation (68 (SD 7) days in milk; DIM) and continued for 26 weeks. Duration of milking and milk yield were measured for each milking. Composition of milk was determined from weekly herd tests, and milk quality from fortnightly somatic cell counts (SCC). Completeness of milking and teat condition were assessed during the study. The bacterial status of quarter milk samples was determined at the beginning and end of the study, and all treated cases of clinical mastitis recorded. ANOVA was used to examine the effect of treatment group on variables of interest.

RESULTS: Total milk, fat and protein yields during the study period did not differ between treatments. On average, 30.3% of the morning and 27.6% of the afternoon milkings of MaxT cows reached the maximum time at which cups were removed, and were therefore shortened. While the average milking time of the slowest-milking cow was longer for the Control compared with MaxT group in Weeks 1–18, the average milking time did not differ between treatments. There was no difference in overall SCC, and the incidence of clinical mastitis, or the percentage of infected quarters at drying-off, was similar for the MaxT and Control cows.

CONCLUSION: The results show that setting a maximum milking time can reduce the milking time of slower-milking cows in a herd without compromising overall herd production and udder health.

CLINICAL RELEVANCE: Although the numbers of cows in the study were small there was no evidence of a major increase in SCC, or subclinical or clinical mastitis when a maximum milking time was set for slower-milking cows.     

The Effect of Truss Removal on the Yield of Early Sown Tomatoes

The effect of removing individual trusses from glasshouse-grown tomatoes was investigated and the results are discussed in terms of carbohydrate source/sink relationships. Removing a truss resulted in yield increases on some of the remaining trusses both above and below the one removed, the largest increases occurring on the trusses adjacent to the removed truss with smaller increases on the more distant ones. This general pattern of yield increases occurred whichever of the first nine trusses was removed. The total yield from plants reduced to nine trusses varied from 91% to 99% of the yield from the control plants with ten trusses, depending on the position of the truss removed. The results suggest that most of the translocated material receive by a truss is derived from the leaves in its immediate vicinity. Also that the removal of a truss sink results in apical and basal movement of the available assimilate to the remaining trusses, perhaps via the internal and external phloem.     

Hydrogen radicals, nitrogen radicals, and the production of O3 in the upper troposphere

The concentrations of the hydrogen radicals OH and HO2 in the middle and upper troposphere were measured simultaneously with those of NO, O3, CO, H2O, CH4, non-methane hydrocarbons, and with the ultraviolet and visible radiation field. The data allow a direct examination of the processes that produce O3 in this region of the atmosphere. Comparison of the measured concentrations of OH and HO2 with calculations based on their production from water vapor, ozone, and methane demonstrate that these sources are insufficient to explain the observed radical concentrations in the upper troposphere. The photolysis of carbonyl and peroxide compounds transported to this region from the lower troposphere may provide the source of HOx required to sustain the measured abundances of these radical species. The mechanism by which NO affects the production of O3 is also illustrated by the measurements. In the upper tropospheric air masses sampled, the production rate for ozone (determined from the measured concentrations of HO2 and NO) is calculated to be about 1 part per billion by volume each day. This production rate is faster than previously thought and implies that anthropogenic activities that add NO to the upper troposphere, such as biomass burning and aviation, will lead to production of more O3 than expected.     

In situ observations of a high-pressure phase of H2O Ice

A previously unknown solid phase of H2O has been identified by its peculiar growth patterns, distinct pressure-temperature melting relations, and vibrational Raman spectra. Morphologies of ice crystals and their pressure-temperature melting relations were directly observed in a hydrothermal diamond-anvil cell for H2O bulk densities between 1203 and 1257 kilograms per cubic meter at temperatures between -10 degrees and 50 degreesC. Under these conditions, four different ice forms were observed to melt: two stable phases, ice V and ice VI, and two metastable phases, ice IV and the new ice phase. The Raman spectra and crystal morphology are consistent with a disordered anisotropic structure with some similarities to ice VI.     

Principles for Sustainable Governance of the Oceans

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.     

浅谈疫病和环境

随着养殖业的发展，环境污染已逐渐成为畜牧养殖中的主要问题之一。畜禽死淘率的增高和药费支出的加大，已经提出了一个危险的信号，提示我们要加强环境的卫生管理，防止病原体污染，这是防止疫病发生的一个关键措施。     

Composition of growth in mice with a major gene for rapid postweaning gain

Previous research from this laboratory identified the existence of a major gene for rapid growth in mice. This trait is expressed as rapid postweaning growth and is inherited as a single recessive gene, designated hg. The hg/hg males and females had greater (P less than .05) body weights at 49-d of age as compared with their Hg/-counterparts; 45.6 +/- .64 and 34.0 +/- .64 vs 33.2 +/- .23 and 27.3 +/- .15 g, respectively. Twenty-four male littermate pairs (hg/hg and Hg/-) were euthanized at 49 d of age for determination of carcass composition. Percentage body water was not affected by genotype (hg/hg, 66.7 +/- .5; Hg/-, 67.8 +/- .3). However, there was a decrease (P less than .05) in percentage body protein (20.2 +/- .1 vs 20.8 +/- .1) and body ash (3.4 +/- .01 vs 3.7 +/- .01) in hg/hg males as compared with Hg/- males, while percentage lipid was significantly increased in hg/hg males (8.7 +/- .5 vs 6.7 +/- .3). When carcass weights were adjusted for differences in dry weight, only body protein was significantly affected by genotype, being greater for hg/hg males (8.54 +/- .19 vs 7.70 +/- .19 g). All other components of body composition were not affected by genotype. The regression coefficient for the covariate of dry weight was significantly different from zero for all carcass components. However, there was no significant difference in the regression coefficient between Hg/- and hg/hg males for each component.(ABSTRACT TRUNCATED AT 250 WORDS)     

Evaluation of the parasitological and production responses of a cow/calf operation to an anthelmintic program with ivermectin

The efficacy of a treatment schedule using ivermectin, given subcutaneously at the rate of 200 micrograms kg-1, to control gastrointestinal parasitism and its effect on liveweight gains was assessed. Two herds with a total of 466 Hereford X Brangus cow/calf pairs were used. Each herd was on six pasture plots of comparable size, stocking rate, and quality and quantity of forage. Pasture groups were paired across the two herds. Pasture groups from one herd were randomly assigned to nonmedicated control and the other three to ivermectin treatment. Treatment assignments per pasture group were reversed in the other herd. The control group contained 118 cows and 112 calves and the medicated group 121 cows and 115 calves. Cows were treated in early July and the calves in late July or early August. Cattle from one herd were weighed on Days -28, 0 (day of cow treatment), 30 (day of calf treatment), 58, and 86, while the other herd was weighed on Days -29, 0 (day of cow treatment), 27 (day of calf treatment), 61, and 89. Day 0 was not the same calendar day for the two herds. Fecal samples for parasite egg counts were obtained from the rectum on weight days from five cows and six calves from each pasture; in most cases the same cattle were sampled each time. Calves treated with ivermectin gained (P less than 0.05) more weight than control calves between day of treatment for cows and the end of the trial.(ABSTRACT TRUNCATED AT 250 WORDS)