Oxytetracycline (OTC) pharmacokinetic values in plasma and bile were ascertained after IV administration of the drug. At 6 hours after administration of 1 mg of OTC/kg of body weight, 2.15% of the dose was found in the bile and 37.6% was found in the urine. At 2 hours after administration, the peak bile-to-plasma OTC concentration ratio was 60:1. Bioavailability of OTC was 47.6% when it was administered orally to fasted turkeys and was 9.4% when administered to fed turkeys.

Pharmacokinetic variables of skeletal muscle creatine kinase (CK) activity after IV administration of a muscle extract; CK bioavailability after IM administration of the muscle extract; and effect of IM administration of saline solution, to appreciate the possible release of CK consecutive to muscle puncture, were determined in 6 cows. A general equation for the quantitative estimation of skeletal muscle damage also was derived. Administration of saline solution IM had no effect on plasma CK activity (ANOVA, P > 0.05) in any of the cows. After IV administration of the muscle extract (150 U/kg of body weight), mean volume of the central compartment, plasma half-life, and plasma clearance of CK were 0.027 +/- 0.007 L/kg, 520 +/- 109 minutes, and 6.43 +/- 2.29 ml/kg/h, respectively. After IM administration (150 U/kg), mean bioavailability of CK was 51 +/- 17% and maximal plasma CK activity (500 +/- 97 U/L) was observed at 454 +/- 131 minutes. The rate of CK activity entry into plasma was determined by use of deconvolution analysis. Two peaks were observed; the first appeared before the 30th minute after IM administration, and the second appeared at 3.3 +/- 1.1 hours. Amplitudes were 6.31 +/- 4.45 and 6.57 +/- 3.08 U/kg/h, for the first and the second peaks, respectively. The quantity of CK liberated from control muscle was 0.69 +/- 0.12 U/kg/h, corresponding to a normal daily catabolism of 5.8 +/- 1.0 mg of muscle/kg. From these results, the following equation can be proposed to determine the corresponding mean equivalent of destroyed muscle (Qmuscle, test article) after IM administration of a test article: Qmuscle, test article (g/kg) = 4.41 X 10(-6) AUC (U/h/L), with AUC being the CK plasma activity area under the curve.

An experiment was conducted to compare the bioavailability of dl-alpha-tocopherol acetate (TA) with that of dl-alpha-tocopherol nicotinate (TN) when administered to sheep, as a single dose, either into the rumen or the peritoneal cavity. A total of 16 sheep were used in a factorial design, with 4 sheep/treatment at the interaction level. In addition, 5 sheep that received no supplemental alpha-tocopherol, were euthanatized at the end of the trial to provide baseline data for tissue alpha-tocopherol concentrations. Curves were fitted to the plasma alpha-tocopherol concentration values, taken over 180 hours after administration of the esters. Availability of TA was greater than TN, as evidenced by the significantly higher curve parameter values (P < 0.05) and tissue concentrations (P < 0.05). Route of administration had a marked effect on availability of TA (P < 0.001), but not of TN.

The pharmacokinetics and bioavailability of rifampin were determined after IV (10 mg/kg of body weight) and intragastric (20 mg/kg of body weight) administration to 6 healthy, adult horses. After IV administration, the disposition kinetics of rifampin were best described by a 2-compartment open model. A rapid distribution phase was followed by a slower elimination phase, with a half-life (t1/2[beta]) of 7.27 +/- 1.1 hours. The mean body clearance was 1.49 +/- 0.41 ml/min.kg, and the mean volume of distribution was 932 +/- 292 ml/kg indicating that rifampin was widely distributed in the body. After intragastric administration of rifampin in aqueous suspension, a brief lag period (0.31 +/- 0.09 hour) was followed by rapid, but incomplete, absorption (t1/2[a] = 0.51 +/- 0.32 hour) and slow elimination (t1/2[d] = 11.50 +/- 1.55 hours). The mean bioavailability (fractional absorption) of the administered dose during the first 24 hours was 53.94 +/- 18.90%, and we estimated that 70.0 +/- 23.6% of the drug would eventually be absorbed. The mean peak plasma rifampin concentration was 13.25 +/- 2.70 microgram/ml at 2.5 +/- 1.6 hours after dosing. All 6 horses had plasma rifampin concentrations > 2 microgram/ml by 45 minutes after dosing; concentrations > 3 microgram/ml persisted for at least 24 hours. Mean plasma rifampin concentrations at 12 and 24 hours after dosing were 6.86 +/- 1.69 microgram/ml and 3.83 +/- 0.87 microgram/ml, respectively. We tested 162 isolates of 16 bacterial species cultured from clinically ill horses for susceptibility to rifampin. All strains of coagulase-positive staphylococci, Streptococcus zooepidemicus, Str equi, Str equisimilis, Rhodococcus equi and Corynebacterium pseudotuberculosis were highly susceptible to rifampin (minimal inhibitory concentration [MIC] less than or equal to 0.25 microgram/ml).

In the conditions of the Republic of Belarus there was determined the productivity and foraging advantages of fodder galega (Galega officinalis) in comparison with the traditional perennial leguminous grasses (alfalfa (Medicago sativa); alsike clover (Trifolium hybridum); cookshead (Onobrychis viceaefolia)) and influence of the analyzed crop of state and internal microbiota of agricultural animals. There was studied the qualitative structure of galega in accordance with the phases of crop development and its influence on physiological functions of animals. It is established, that in the conditions of northern region of Belarus the fodder galega provided the yielding capacity of dry matter of 11,3 t/ha that exceeded the indices of alfalfa on 13,9%, alsike clover - in 2,7 times and cookshead - in 2,1 times. By the third decade of May it formed 18-20 tons green mass that made it possible to feed animals on 10-15 days earlier, than with other leguminous grasses. High degree of leafage (65,7%) preconditioned its high nutritional value. Fodder galega has high level of calcium, potassium, phosphorus and some microelements: copper, zinc, manganese, cobalt. Studying of vitamin value of fodder galega showed that its green mass was vitamin-rich, had enough of irreplaceable amino acids. It was established, that hay of fodder galega had high level of the non-decomposed protein (68,6-71%) that was very important for feeding of highly productive cows. It increased the level of crude protein in experimental animals on 8%.

In the conditions of application of enzyme preparations there is the possibility of inclusion into mixed fodders structure of such cheap fodder grains as rye. Determination of the optimal dose of introduction of the liquid enzymatic fodder additive (xylanase – 8800 units; phytase – 600 units; cellulose – 880 units; r-gluco – 4000 units; a- amylase – 200 units) and its influence on stores productivity during the completion of growing and fattening periods was realized in the conditions of the Republic of Belarus. Research results showed the following: inclusion into mixed fodders of the increased amount of rye grain (without the enzyme additive) for stores feeding during the completion of growing (20%) and fattening (30%) periods did not render negative influence on experimental animals; the optimal dose of the trial enzyme for stores during the completion of growing period - (SK-21 including rye grain - 20%) was 200 ml per 1 t of mixed fodders; the optimal dose of the trial enzyme for stores during the fattening period (KDS-26 including rye -30%) was 150 ml per 1 t of mixed fodders. Application of the experimental fodder additive promoted the increasing live weight gain. There was noted the tendency of the positive influence of the analyzed enzyme on dry and organic matter, fat, dietary fibre and nitrogen-free extractive substances digestibility

Research on preserving ability of the biological preserving agent Bioplant for grass and maize silage making was realized in the conditions of the Republic of Belarus. Application of Bioplant in course of grasess and maize encilaging promoted the faster accumulation of the significant amount of milk acid and decreasing of рН up to 4,1-4,2. Silage which was prepared with preserving agent Bioplant corresponded to the top grade of quality. Application of Bioplant for preparation of siloed forages promoted the reduction of losses at their storage. For example, in grass-legume and cereal silage there was a reduction of dry matter losses in comparison with control silage - on 4,7 and 4,2%, crude protein - on 5,6 and 5,0%, respectively. In maize silage the addition of the preserving agent there was stated the decreasing of nutrient losses in comparison with the control: dry matter - on 5,2%, crude protein - on 6,2%. Feeding of wedder hogs with the silage preserved by the preserving agent Bioplant provided higher digestibility of crude protein in comparison with the control group: on 3,2% in the conditions of grass-legume silage use, on 2,4% - in the conditions of feeding with cereals, and on 2,9% - in the conditions of feeding with maize silage

There was realized the estimation of influence of application of biometals in a ration of chickens-broilers of different age on the content in their blood macro-and microelements. It is possible to make the conclusion, that in blood of chickens-broilers the tendency to decrease with the years concentration of calcium and magnesium, to increase of level of phosphorus, zinc and copper, and also increase the content of cobalt with 23-day age to 33-day and its insignificant decrease by 45 day of a life of chickens takes place. At the same time application in a ration of chickens-broilers of biometals sodium-ferrum-ethylenediaminetetraacetate (Na-Fe-etda) from calculation of 2,5 mg/kg, sodium-zinc-ethylenediaminetetraacetate (Na-Zn-etda) - 5,5 mg/kg, sodium-cobalt- ethylenediaminetetraacetate (Na-Co-etda) - 5,5 mg/kg and sodium-cuprum-ethylenediaminetetraacetate (Na-Cu-etda) - 3,5 mg/kg of body weight in the basic weight led to small increase of level macro- and microelements in blood of chickens-broilers and did not render negative influence on safety and a gain of body weight of chickens in trial group. Data on concentration of macro- and microelements in blood and a body weight gain of chickens-broilers are presented. | Целью работы является оценка влияния применения биометаллов в рационе цыплят-бройлеров разного возраста на содержание в их крови макро- и микроэлементов. Можно сделать заключение, что в крови цыплят-бройлеров имеет место тенденция к снижению с возрастом концентрации кальция и магния, повышению уровня фосфора, цинка и меди, а также увеличению содержание кобальта с 23-дненвного возраста к 33-дневному и незначительному снижению его к 45-му дню жизни цыплят. В то же время применение в рационе цыплят-бройлеров биометаллов натрий-ферум-этилендиаминтетраацетат (Na-Fe-etda) из расчета 2,5 мг/кг, натрий-цинк-этилендиаминтетраацетат (Na-Zn-etda) - 5,5 мг/кг, натрий-кобальт-этилендиаминтетраацетат (Na-Co-etda-) - 5,5 мг/кг и натрий-купрум-этилендиаминтетраацетат (Na-Cu-etda) - 3,5 мг/кг живой массы в основной своей массе приводило к небольшому повышению уровня макро- и микроэлементов в крови цыплят-бройлеров и не оказывало негативного воздействия на сохранность и прирост живой массы цыплят опытной группы. Представлены данные по концентрации макро- и микроэлементов в крови и прирост живой массы цыплят-бройлеров.

In the conditions of the Republic of Belarus there were studied the productive and interior indexes of bull calves which were fed with dried distiller's grains. Inclusion into bull calves diets of the mixed fodder containing 33% of dried distiller's grains made it possible to increase the concentration of volatile fatty acids on 16-18%, albuminous nitrogen - on 4-7%, quantity of infusorians - on 16-17%, as well as to reduce the ammonia level in a ruminal liquid from 23,4 up to 17 mg%. Inclusion of 33% of dried distiller's grains into structure of mixed fodder and feeding the same quantity of fresh distiller's grains promoted increasing of nutrient digestibility on respectively 4,0-5,9% and 3,5-4,5%, nitrogen retention - on 13%. Increasing of level of dried distiller's grains in structure of grain forage up to 67% increased the digestibility of nutrients on 1,5-2% and nitrogen retention - on 4%. Substitution in mixed fodder for bull-calves of 33 and 67% of fodder grain by dried distiller's grains made it possible to increase daily average live weight gain of animals respectively on 10 and 4%. Feeding of dried and fresh distiller's grains at simultaneous introduction in rations of complex mineral additive promoted the activation of metabolic processes that was proved by increasing of crude protein of blood at 6-7% and 5-8%, as well as decreasing of concentration of urea - on 25 and 22% respectively. Use of 33% of dried distiller's grains as a part of mixed fodder for cattle young stock proved to be economically effective and allowed to lower the cost price of a live weight gain on 10-11%. Feeding with fresh distiller's grains allowed to lower the prime cost price on 7% and to receive additional profit.

In the conditions of the Republic of Belarus there was studied the yielding capacity and quality composition of nontraditional high-energy crops (sorghum and Sudan grass hybrid; millet (Panicum); white panicum (Japanese millet)) as well as there was developed a technology fodder conservation. In course of the study there was analyzed accumulation of nutrients in accordance with crop development phases and their quality composition; also there was determined a method of application of grass stands of the studied crops for their production use. It is established, that the most suitable for conditions of Vitebsk region from high-quality cultures is sorgho-sudan-grass hybrid which reaches phases of seed formation and provides productivity of dry matter more than 9 t/ha with humidity of green mass of 69% that is optimum for preparation of tinned forage. Sugar sorgho and grain is reached by phases of ear formation and have provided productivity of green mass of 25,9-25,7 t/ha, dry matter - 3,5 t/ha. To use double-cut sorgho-sudan-grass hybrid on a silo less effectively as the received green mass has high humidity (92%), and the general gathering of dry matter twice more low, than at single-cut use. At single-cut use the culture reaches phases of grain formation in which contains about 31% of dry matter that is favorable for conservation. Double-cut use of sorgho-sudan-grass hybrid is comprehensible at its cultivation in the green conveyor to use as green top dressing during the pasturable period. Japanese millet is better to use double-cut as it has provided the maximum productivity of green mass of high quality (63,9 t/ha) and dry matter (9,1 t/ha), it is in 2,3 and 1,6% of time above, than at single-cut use. Single-cut crops of sorgho-sudan-grass hybrid are expedient for using as a component at siloing of galega orientalis. In an early phase of development (7-8 leaves) the new-mown green mass of sorgho-sudan-grass hybrid possesses toxicity on the bottom border of average degree, but in 2 hours after mowing the forage becomes not toxic. In later phase of development there is an accumulation of sugars, and new-mown mass of sorgho is nontoxical. Sorghum cultures contain high percent of non-decomposed protein - 58,3-84,6% that is very important in feeding of highly productive cows.