Clean wool colour and fatty acid content of semi fine wool

D. Pamukova

The purpose of the present investigation was to compare the clean wool colour and the fatty acid composition of semi fine wool. The
investigation was performed on 93 individual samples (from the shoulder, the back and the thigh) of 31 fleeces obtained from industrial batches of semi fine wool originating from Bulgaria, The Republic of Macedonia and The Netherlands. For shoulder, back and leg samples, the greasy wool colour, the staple length and the dirt percentage were determined. For shoulder samples, the clean wool colour, the total lipids in wool grease and its fatty acid composition were additionally determined. The lowest colour index, measured on full-length staple, was that of Dutch wool (34.86). Similar colour index was obtained for Bulgarian (50.43) and Macedonian (51.57) wool batches. After removal of the dirty area, Dutch wool exhibited the lowest colour index again (29.86), followed by Macedonian (38.54) and Bulgarian (42.51) samples. The greasy wool colour (except for yellow-coloured wool) could not be used as a reliable criterion for prediction of clean wool colour.

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Relationship between protostrongylid infections of land snails and the pasture vegetation in the region of Stara Zagora, South Bulgaria

The relationship between protostrongylid infections of land snails and the type of pasture vegetation was investigated on nine pastures in the Stara
Zagora region. The pastures were characterized by considerable diversity of the vegetation species. Third-stage larvae of Muellerius capillaris, Neostrongylus
linearis, Cystocaulus ocreatus and Protostrongylus sp. were detected. The multiple regression analysis confirmed correlations between vegetation and the
parameters of protostrongylid infection in the main intermediate host Helicella obvia. The type of the primary vegetation was the only predictor in regression
models for the total prevalence of protostrongylids and the prevalence of the most commonly encountered species M. capillaris.

Relationship between protostrongylid infections of land snails and the pasture vegetation in the region of Stara Zagora, South Bulgaria

D.Georgiev

Plant protection means against Oilseed rape pests

Oilseed rape, together with its industrial, biological and agricultural advantages, appears as a good host plant to a lot of harmful insects. They appear
often as a calamity and lead to considerable damages. Thus, the aim of the present investigation is to approve the influence of some pest control chemicals
against cabbage bugs -Eurydema ornata L. and pollen beetles – Meligethes aeneus F. We carried out the investigation in 2004/2005. Each of the chemicals was
used in three different concentrations in order to determine the concentration dependency effect. The mortality rate was calculated by the Berim’s formula.
Based on the results it was established that Vaztak 10 EK in concentration 0.03% could be recommended as a preparation with multipurpose effects against
pollen beetles – Meligethes aeneus F. and cabbage bugs – Eurydema ornata L.

Plant protection means against Oilseed rape pests

Evaluation of deoxynivalenol and virulence in dsRNA containing Fusarium graminearum Isolates

Double–stranded RNA (dsRNA) viruses in some fungi are associated with hypovirulence and have been used or proposed as biological control
agents. To determine the effect of dsRNA on pathogenicity and deoxynivalenol (DON) production by Fusarium graminearum isolates, the causal agent of
wheat head blight, three dsRNA–containing and dsRNA–free isolates were screened in this survey. Between the two groups, the disease severity of the
dsRNA-containing isolates, however, was significantly (p<0.01) less than that of the dsRNA–free isolates on susceptible wheat (cv. Falat) in a greenhouse
experiment. DON production by dsRNA–free and dsRNA-containing isolates of F. graminearum was confirmed using HPLC techniques. The range of in
vitro DON production levels varied from 0.07 to 1.62 ppm, and 0.06 to 0.4 ppm, respectively. A significantly reduced level of DON up to 50% was detected
in dsRNA-containing derivatives than the dsRNA–free isolates. Meanwhile, the range of DON production levels in spikes inoculated with dsRNA–free and
dsRNA-containing F. graminearum isolates varied from 0.56 to 0.9 ppm and 0.37 to 0.63 ppm, respectively. These results indicated 27.5% reduction in
DON production.

Evaluation of deoxynivalenol and virulence in dsRNA containing Fusarium graminearum Isolates

Said Abbas1, Aminian Parisa2, Alizadeh Azizollah2, Safaie Naser2

Study of the possibility for twofold harvesting of annual late spring crops and mixtures in the foremountain regions of the Central Balkan mountains

During the 2007-2009 period in the Institute of Mountain Stockbreeding and Agriculture – Troyan a study was conducted on the possibility for twofold
harvesting of annual late spring crops and mixtures for production of forage. Three pure stands of grass and legume crops and 2 mixtures between them were
tested in the following variants: 1. Spring pea “Pleven 4”; 2. Sudangrass (Control); 3. Sorghum-Sudangrass hybrid; 4. Sudangrass + Spring pea; 5. SorghumSudangrass
hybrid + Spring pea.It was found that under initial harvesting at the time of earing/heading (1st stage) or at the beginning of flowering of grass crops
(2nd stage) the sorghum-Sudangrass hybrid and its mixture with spring pea was distinguished for the maximum productivity, exceeding the control stand of
Sudangrass by 55.03 and 51.98% and by 48.82 and 41.78%, respectively. At both stages after the first harvesting the yields from the second cut were formed by
the grass crops. Irrespective of the stage of initial harvesting and nature of the stands (pure or mixed), the sown forage crops occupied the greatest relative
portion in the areas, the mixed stands having the lowest weed infestation.

Study of the possibility for twofold harvesting of annual late spring crops and mixtures in the foremountain regions of the Central Balkan mountains

V. Lingorski1, T. Kertikov2

Comparison of the effects of Natuphos® 5 000 G and Optiphos® phytases utilization in broiler chicken feeding with maize-soybean diets

An experiment with 96 male broiler chickens (hybrid ROSS 308), distributed in 3 groups, 32 chickens each, was conducted. Each group consisted of
4 subgroups, 8 chickens each. Live weight, the retention of nitrogen, calcium and phosphorus in the chickens’ organisms were monitored at the age of 1, 11, 29
и 42 days. The birds received 3 types of compound feed. The control group birds were fed a maize-soybean diet without phytase and the birds from the
experimental groups were fed a diet, supplemented by Natuphos 5000G or Optiphos phytase. Diets for all growing periods were balanced as to CP, Ca and
available phosphorus. In the phytase groups the total phosphorus quantity was decreased from 0.81% to 0.66% for the starter period, from 0.76 to 0.61% for
the grower one and from 0.72% to 0.56% for the finisher period. The obtained results showed that phytase supplementation to the maize-soybean diet
improved the utilization of nitrogen, calcium and phosphorus and the tibia ash quantity in broiler chickens during the 0-42–day-period. For the whole fattening
period broilers fed maize-soybean diets supplemented by Natuphos or Feedophyt phytase had a reliably higher live weight by 10.95% and 11.93%,
respectively, in comparison with the group without phytase. The forage consumption for 1 kg weight gain in chickens decreased by 17.02% (p ≤ 0.01) on
average as a result of the use of exogenous phytase. By supplementing phytase to a maize-soybean diet the quantity of dicalcium phosphate decreased by
34% (0-42 days) thus reducing the price of compound forage.

Comparison of the effects of Natuphos® 5 000 G and Optiphos® phytases utilization in broiler chicken feeding with maize-soybean diets

P. Valkova

Investigations on the content of lead and cadmium in compound feed additives

The lead and cadmium content of samples from the most commonly utilized feed additives (limestone, dicalcium phosphate, sodium chloride,
zinc, vitamin and trace element premixes) was analyzed by means of atomic absorption spectrophotometry. It was found out that up to 30% of the allowed
limit for lead content and up to 100% of the allowed limit of cadmium content in compound feed for layer hens could be attributed to limestone, therefore
emphasizing the importance of monitoring lead content of this ingredient. Additives such as dicalcium phosphate, trace element mixes, vitamin premixes
and particularly sodium chloride, could also contribute to the higher lead and cadmium content in compound feed. As these ingredients are included at
quite low levels, the risks for increasing lead and cadmium content of compound poultry feed through them is assessed as insignificant.

Investigations on the content of lead and cadmium in compound feed additives

D. Alexieva1, S. Chobanova2

Relation between time to heading and date of maturity of winter common wheat varieties (Triticum aestivum L.)

The changed duration of the time to heading and maturity is an important element of the wheat’s adaptability to specific production conditions. The
question whether a variety early by its heading date remains early by its maturation date is a significant one, but the data on this problem is rather limited.
Therefore the aim of this investigation was to find out if there is any specificity between the varieties by their response to the environment with regard to heading
date and maturation date and if there is any relation between these periods in the common wheat varieties different by their earliness. After preliminary
observations in the trial field of DAI, General Toshevo, ten early and ten late wheat varieties and lines were selected and analyzed. The dates to heading and
physiological maturity were studied. They were identified visually at stage 55 and 94, respectively, by the scale for wheat growth and developments during 2004
– 2009. The genotype, the year conditions and the sum of temperatures (GDD) interacted significantly with the dates of the two traits and therefore affected their
variation. The heading date varied in a similar way in positive or negative direction in both variety groups. The correlations between the dates to heading and
maturity were high and significant regardless of the variety group (r=0.858, r=0.755, respectively). The period between heading and physiological maturity
(grain filling) varied according to the temperatures of the respective year. The date to heading can on the whole be used as a criterion for distinguishing wheat
varieties by their growing period durability. The time from heading to grain maturity was clearly less affected than the time to heading and depended mostly on
the genotype.

Relation between time to heading and date of maturity of winter common wheat varieties (Triticum aestivum L.)

N. Tsenov

Influence of genotype and environments on quality of winter wheat varieties in Northern Bulgaria

The investigation included 16 varieties from first and second quality group according to the Bulgarian state standard. The aim of the investigation was
to find out the level of influence of different environmental factors on wheat quality indices; to follow the response of the varieties to various combinations of
growing conditions; to investigate the ability of the varieties to realize their potential for quality under specific environments. The investigation was carried out at
Dobrudzha Agricultural Institute – General Toshevo (DAI) and at Institute of Agriculture and Seed Science, Obraztsov Chiflik, Rouse (OCH) during 2004 – 2007
by the Latin square method in 5 replications. The expression of 6 grain quality indices which give information about various quality aspects was analyzed: test
weight, sedimentation value of flour, wet gluten content in grain, valorimeric value (valorimeter, conditional units), and loaf volume, determined according to the
methods adopted at the DAI laboratory. It was found out that the independent influence of the genotype had the lowest effect on the variation of the quality
indices of the investigated wheat varieties. The influence of the location was the highest on wet gluten content and valorimetric value. The year conditions had
the highest effect on the expression of the characters test weight and loaf volume. The varieties from the quality group, compared to the varieties from the
second group as a whole, realized their quality potential under more favorable combinations of conditions. Compared to the quality standard Pobeda, the
varieties from the first group, which had lower mean values, were more stable to the changeable growing conditions. The varieties with higher indices differed in
their response according to the standard. Most susceptible to changeable environments were varieties Demetra and Zlatina, and most stable were varieties
Aglika, Albena and Preslav.

Influence of genotype and environments on quality of winter wheat varieties in Northern Bulgaria

D. Atanasova, V. Dochev, N. Tsenov, I. Todorov

Effects of days open on the milk yield and the duration of the concurrent lactation in Bulgarian Murrah buffaloes

A study assigning 1021 lactations of 313 Bulgarian Murrah buffalo cows with milk yield recorded on the farm of Agricultural Institute – Shumen during
the period 1967-2001 was initiated with the objective to estimate the effect of days open on the milk yield and the duration of the concurrent lactation. Using
linear LS-analyses, significant antagonistic effect of days open on 305-day milk yield and especially on complete days in milk was established. Service period of
three to five months is expected to be the most beneficial for the balance between reproductive efficiency and productive performance, at preferable lactation
duration.

Effects of days open on the milk yield and the duration of the concurrent lactation in Bulgarian Murrah buffaloes

P. Penchev, Y. Ilieva, Tz. Peeva