Soil carbon and physical property changes in Brazilian Coastal Tableland soils with land use following deforestation

The Atlantic Forest has been deforested to the point that only about 7% of the original forest remains. Soil degradation, including loss of soil organic carbon (SOC), has often been associated with deforestation. In extensive areas previously occupied by Atlantic Forest the soil has a naturally compact subsoil horizon called the coeso. This layer challenges root development and plant productivity. The purpose of this study was to investigate soil carbon and selected physical characteristics under the influence of the native forest and post-deforestation agricultural practices. The management regimes were a native forest, a rubber tree plantation, a pasture and annual cropping. Two soil depths were investigated: 0 to 15 cm, corresponding to the A horizon; and 35 to 50 cm, corresponding to the coeso. Management influenced both SOC concentration and soil bulk density; however, SOC content was not significantly changed by any of the post-deforestation land uses. This result supports the annual cropping system that has been adapted by small landholders. Most interesting was the quantity of SOC found in the coeso, which was as much as 50% of the surface horizon.     

Occurrence of Raoiella indica Hirst (Acari,Tenuipalpidae) in the Southeast region of the state of Pará, Brazil

Journal of Plant Diseases and Protection - The red palm mite Raoiella indica Hirst attacks coconut, banana and açai trees. In 2007, the mite was recorded for the first time in South America....     

Performance and nematode infection of ewe lambs on intensive rotational grazing with two different cultivars of <Emphasis Type="Italic">Panicum maximum</Emphasis>

The daily live weight gain (DLWG), faecal nematode egg counts (FEC), and packed cell volume (PCV) of Suffolk, Ile de France and Santa Inês ewe lambs were evaluated fortnightly for 56 days in the dry season (winter) and 64 days in the rainy season (summer) of 2001-2002. The animals were distributed in two similar groups, one located on Aruana and the other on Tanzania grass (Panicum maximum), in rotational grazing system at the Instituto de Zootecnia, in Nova Odessa city (SP), Brazil. In the dry season, 24 one-year-old ewe lambs were used, eight of each breed, and there was no difference (p > 0.05) between grasses for DLWG (100 g/day), although the Suffolk had higher values (p < 0.05) than the other breeds. In the rainy season, with 33 six-month-old ewe lambs, nine Suffolk, eight Ile de France and 16 Santa Inês, the DLWG was not affected by breed, but it was twice as great (71 g/day, p < 0.05) on Aruana as on Tanzania grass (30 g/day). The Santa Inês ewe lambs had the lowest FEC (p < 0.05) and the highest PCV (p < 0.05), confirming their higher resistance to Haemonchus contortus, the prevalent nematode in the rainy season. It was concluded that the best performance of ewe lambs on Aruana pastures in the rainy season is probably explained by their lower nematode infection owing to the better protein content of this grass (mean contents 11.2% crude protein in Aruana grass and 8.7% in Tanzania grass, p < 0.05) which may have improved the immunological system with the consequence that the highest PCV (p < 0.05) observed in those animals.     

Total tract nutrient digestion and milk fatty acid profile of dairy cows fed diets containing different levels of whole raw soya beans

Whole oilseeds such as soya beans have been utilized in dairy rations to supply additional fat and protein. However, antinutritional components contained in soya beans, such as trypsin inhibitors and haemagglutinins (lectins) may alter digestibility of nutrients and consequently affect animal performance. The objective of the present experiment was to quantify the effect of different levels of whole raw soya beans in diets of dairy cows on nutrient intake, total tract digestion, nutrient balances and milk yield and composition. Sixteen mid to late‐lactation cows (228 ± 20 days in milk; mean ± SD) were used in four replicated 4 × 4 Latin square design experiment with 21‐d periods. Cows were assigned to each square according to milk yield and DIM. The animals were randomly allocated to treatments: control (without soya beans addition; CO), WS9, WS18 and WS27, with addition of 9%, 18% and 27% of whole raw soya bean in diet on a dry matter (DM) basis respectively. All diets contained identical forage and concentrate components and consisted of maize silage and concentrate based on ground corn and soya beans at a ratio of 60:40. There were no differences in OM, CP, NDF and NE_L intakes (kg/day and MJ/day) among the treatments (p > 0.05). However, DM and NFC intakes were negatively affected (p = 0.04 and p < 0.01, respectively) and ether extract (EE) intake was positively affected (p < 0.01). Total tract digestion increased linearly with whole raw soya beans for EE (p < 0.01) and NDF (p = 0.01). The excretion (kg/day) of digested soya beans grains increased linearly according to addition of whole raw soya beans. However, the nutritive characteristics of excreted grains were not altered. Milk (kg), milk lactose (kg) and protein (kg) yield decreased linearly (p < 0.01, p < 0.01 and p = 0.04, respectively) milk fat content (%) increased linearly (p < 0.01) with whole raw soya beans inclusion. Increasing addition of whole raw soya beans affected milk fatty acid profile with a linear decrease of cis‐9‐trans 11CLA and total saturated FA; and linear increase of total unsaturated and C_18:3 FA. Energy balance was positively affected (p = 0.03) by whole raw soya beans as well as efficiency of NEL milk/DE intake (p = 0.02). Nitrogen balance and microbial protein synthesis were not affected by whole raw soya beans. Increasing doses of whole raw soya beans decreased dry matter intake and milk yield, however, led to an increase of unsaturated acids in milk and higher milk fat concentration.     

<Emphasis Type="Italic">Staphylococcus aureus</Emphasis> intramammary infection affects milk yield and SCC of dairy cows

Staphylococcus aureus (S. aureus) is the most prevalent infectious microorganism affecting dairy cattle worldwide, and its pathogenic characteristics facilitate its spread in dairy herds. S. aureus intramammary infections (IMI) are mainly subclinical, and associated losses can exceed average herd losses where the pathogen is not isolated. However, the extent it affects milk composition at udder and quarter levels is still unknown, and cow composite milk losses may be underestimated due to the dilution effect. The aim of this study was to investigate the effects of S. aureus subclinical mastitis on mammary quarter milk yield and composition. In order to determine the effects of the pathogen on milk yield and composition at quarter level, a pairwise comparison of infected and non-infected mammary quarters (n?=?28) from two dairy herds was carried out. Quarters were individually milked, and milk production and composition were assessed. S. aureus has increased somatic cell counts at quarter level; however, no effect of S. aureus IMI on milk lactose, fat, and protein contents was observed. Fat yield from infected quarters decreased, but losses due to the infection caused by S. aureus were not associated with quarter positioning in cows.     

Starch levels on performance,milk composition and energy balance of lactating dairy cows

The objective of this experiment was to evaluate the effects of starch levels in diets with the replacement of citrus pulp for corn on milk yield, milk composition, and energy balance of lactating dairy cows. Twenty-eight multiparous Holstein cows were used in seven 4?×?4 Latin squares conducted concurrently, and each experimental period consisted of 20 days (16 days for adaptation and 4 days for sampling). The experimental treatments comprised four starch levels: 15, 20, 25, and 30 % in the diet. The dry matter intake increased linearly with increasing starch levels. The milk yield and 3.5 % fat-corrected milk yield showed quadratic response to increasing starch levels. The milk protein content and milk total solids content responded linearly to increasing starch levels. The feed efficiency, milk lactose content, milk urea nitrogen, plasma urea nitrogen, and plasma glucose concentration were not affected by starch levels. The estimated net energy for lactation (NE_L) intake increased linearly as the starch level was raised. Although the milk NE_L output per kilogram of milk was not affected by starch, the milk NE_L output daily responded quadratically to starch levels. In addition, the NE_L in body weight gain also responded quadratically to increasing starch levels. The efficiency of energy use for milk yield and the NE_L efficiency for production also responded quadratically to increasing starch levels. Diets for mid-lactating dairy cows producing around 30 kg/day of milk should be formulated to provide around 25 % starch to optimize performance.

     

Evaluation of external markers to estimate fecal excretion,intake, and digestibility in dairy cows

Tropical Animal Health and Production - The objective of this study was to compare the use of an external marker titanium dioxide (TiO2) as an alternative to chromic oxide (Cr2O3) in dairy cows....     

Soil Enzymatic Activity in Eucalyptus Grandis Plantations of Different Ages

Eucalyptus plantations have become increasingly common in Latin America. However, because Eucalyptus is an exotic species, its presence has raised concerns about changes in the environment, especially to soil properties. The objective of this study was to investigate possible changes in selected soil enzyme activity after several years of Eucalyptus cultivation. Soil samples were collected from four locations: a native forest (Atlantic Forest) used as a reference for the original soil conditions and three E. grandis plantations aged 2, 3 and 5 years, established in 2008, 2007 and 2005, respectively. The native vegetation had been removed and the soil graded and ploughed to establish these plantations. We evaluated soil enzymatic activities (β‐glucosidase, acid phosphatase, dehydrogenase, urease and arylsulfatase) at each location. The activity of β‐glucosidase, phosphatase, dehydrogenase and urease was improved after 5 years, whereas arylsulphatase was impacted negatively. The multivariate analysis showed that the majority of enzyme activities reached the values observed in native forest after the third year of reforestation. The activity of β‐glucosidase was crucial in differentiating the area with 2 years of reforestation from the native forest. The removal of native vegetation in order to establish commercial plantations raises concerns about the real impacts of this practice on the soil. In the present study, plantations of Eucalyptus improved most of the selected enzyme activities after the third year of reforestation. Copyright © 2015 John Wiley & Sons, Ltd.