The purposes of this study were to describe the clinical signs observed in PRRS positive herds during a porcine reproductive and respiratory syndrome (PRRS) outbreak in Ontario and to determine associations between these clinical signs and herd demographics and PRRS control strategies. All PRRS polymerase chain reaction-(PCR)-positive submissions to a diagnostic laboratory between September 1, 2004 and August 31, 2007 were identified (n = 1864). After meeting eligibility requirements and agreeing to voluntary study participation, producers from 455 of these submissions were surveyed for information on clinical signs observed in their herds, herd demographics, and PRRS control strategies used in their herds at the time that the PCR-positive samples were taken. Larger herd size was associated with an increased risk of reporting abortion, weakborn piglets, off-feed sows, and sow mortality in sow herds, and with an increased risk of reporting mortality in finishing herds. When disease control strategies were examined, use of a commercial PRRS vaccine in sows and gilts was associated with a decreased risk of reporting weakborn pigs and high pre-weaning mortality, while the use of serum inoculation in breeding animals was associated with an increased risk of reporting off-feed sows and sow mortality. Providing biofeedback of stillborn/mummified piglets, placenta or feces to gilts was associated with an increased risk of reporting respiratory disease and mortality in finishing pigs while all-in/all-out flow in farrowing rooms was associated with an increased risk of reporting sow mortality and weakborn piglets.

Eight female piglets from each of three farrowed crossbred (75% Hampshire x 25% Local) gilts grouped as A, B and C were weaned at 28, 42 and 56 days respectively. Piglets of each weaned groups were divided into two sub-groups _ 'a' and 'b' consisting of 4 piglets in each. Piglets of sub-groups _ 'a' were supplemented with strategic mineral mixture while the piglets of sub-group 'b' were offered commercial mineral mixture. There was significant (P0.01) rise of serum oestradiol-17â at the pubertal oestrus compared to the levels before puberty in gilts. Oestradiol concentration did not differ significantly among piglets weaned at different days of age and between piglets supplemented with strategic and commercial mineral mixture. Serum progesterone was lowest during oestrus and highest on day 10 of the oestrus cycle in all the groups. Progesterone concentration in the piglets weaned at different days of age did not differ significantly. However, the level was found significantly (P 0.05) high in piglets supplemented with strategic mixture over the piglets supplemented with commercial mineral mixture.

The spectrum of acaricides changes continuously and improves. At the same time, big attention is given to research of new, more effective preparations meeting modern requirements. Research on studying the efficiency of Akaribil preparation against swine sarcoptosis (Sarcoptidae) was realized in the conditions of swine breeding farm in the Republic of Belarus. The preparation possesses high insect-acaricidal activity. In the conditions of the preparation storage and repeated opening of a ware in the course of tests there were stated no changes in drug smell or color. The scheme of the preparation application is applied in industrial production technology. It possesses anti-inflammatory properties, antiseptic stimulating healing of skin damages, does not irritate integuments, renders weak irritating effect on mucous membranes of eyes. In recommended doses Akaribil does not cause any adverse effects and complicating disease. There were stated no contraindications to preparation application. High therapeutic efficiency against arachnoentomosis was proved. Application the preparation made it possible not only to reduce disease incidence and animal death, but also to facilitate the severity of scabietic diseases. As a result of realized research it was established that efficiency of Akaribil against swine sarcoptosis was 100%.

In the conditions of the Republic of Belarus as a result of task-specific selection and breeding work there was developed and approbated Berezinsky breed type of Belarusian meaty breed. Sows of the studied breed type were notable for high indices of reproductive signs: the average multiple pregnancy in three breeding swine herd was 11,1 pigs per farrowing; milkability - 55 kg, litter size at weaning stage at 35-day age - 87,1 kg. The predominancy over the forecast exponent indices made 4,7-5,7%. In course of the study there were analyzed the forecasted indexes of the basic breeding signs of Berezinsky breed type of Belarusian meaty breed for 2005-2010; productivity indices of the experimental sows; coefficient of variations of sow productivity.

In the conditions of the Republic of Belarus there was studied the influence of methods and means of spot heating and localization of warmth on indexes of microclimate in piglet breeding houses and resting area of piglets and their growth parameters. In course of the study there taken into consideration the indexes of an average temperature on piglet resting area housings; atmosphere relative humidity, air velocity, content of carbon dioxide, content of hydrogen nitride in the housing and resting areas of piglets. Research results of microclimate of swine breeding areas and resting areas of piglets under different means and methods of heating and warmth localization showed that the it was the most efficient to add for the local heating in the first three weeks of suckling period the glow-discharge tubes or in suckling period or weanling periods - the heated floors; and in suckling period - brooders in the form of tops with shields.

In the conditions of the Republic of Belarus there was studied the morphology and growth dynamics of vomeronasal cartilage of swine at postnatal period. The vomeronasal cartilage covers the vomeronasal body outside. Lateral and medial bases of vomeronasal cartilage formed an antrum in which there was an organon vomeronasal. The most intensive growth of a cartilage of pigs occurred in the first two months of animal life. Arrangement of cartilage was dissymmetric - at the right it was sited more caudad than at the left; this fact caused the differences in its dimensions at the transverse sections.

On the basis of realized in the conditions of the Republic of Belarus research it was established, that Cryptosporidial infection was found at adult and young pigs. The data on influence studying cryptosporidiosis invasion on pathomorphological changes in internal organs of piglets in the conditions of an associative course with infectious. Associative diseases give clearer clinical findings and proceed much harder, with heavier morphological changes. The majority of diseases in the conditions of an associative course proceeds harder in comparison with a mono-infection or invasion. In the conditions of mono-invasion the basic changes are localized in small intestines, causing acute and subacute catarrhal enteritis and a serous inflammation of regional mesenteric lymphonodus. These histological processes are presented as non-uniform locus of infection of a mucous membrane of intestines with atrophy of villus, hypertrophy of crypth and mononuclear polymorphic-nuclear infiltration of basal membranes. In the conditions of association of Cryptosporidial infection with infectious diseases it was noted that the pathomorphological changes progress and are showed not only by catarrhal, but also by hemorrhagic and local necrotic enteritis. Epithelium of mucous membrane is exposed to desquamation, intestines walls become thinner because of meteorism. Thick intestines are also involved into inflammatory process. Associations of Cryptosporidial infection with infectious diseases lead to development of severe pathomorphological changes in intestines. Alteration has prevailing character that is expressed in progressive development of atrophic, dystrophic processes and decline of cells and tissues that conducts to increase of permeability of vessels and proliferation of cells of reticuloendothelial system. | На основании проведенных исследований установлено, что криптоспоридиозная инвазия выявляется у поросят. Представлены данные по изучению влияния инвазии криптоспоридиоза на патоморфологические изменения во внутренних органах поросят при ассоциативном течении с инфекционными болезнями. Ассоциативные заболевания дают более яркую клиническую картину и протекают гораздо тяжелее, с более выраженными морфологическими изменениями в организме. Большинство болезней при ассоциативном течении протекает более тяжело в сравнении с моноинфекцией или инвазией. При моноинвазии основные изменения локализуются в тонком кишечнике, вызывая острый и подострый катаральный энтериты и серозное воспаление регионарных брыжеечных лимфоузлов. Гистологические данные процессы представлены, как неоднородные участки инфицирования слизистой оболочки кишечника с атрофией ворсинок, гипертрофией крипт и мононуклеарной полиморфнооядерной инфильтрацией базальной мембраны. При ассоциации криптоспоридиоза с инфекционными заболеваниями патоморфологические изменения прогрессируют и проявляются не только катаральным, но геморрагическим и очаговым некротическим энтеритами. Эпителий слизистой оболочки подвергается десквамации, стенки кишечника истончаются вследствие метеоризма. В воспалительный процесс также вовлекается толстый кишечник. Ассоциации криптоспоридиоза с инфекционными заболеваниями приводят к развитию в кишечнике тяжелых патоморфологических изменений. Альтерация имеет преобладающих характер, что выражается в прогрессивном развитии атрофических, дистрофических процессов и некроза клеток и тканей, что ведет к повышению проницаемости сосудов и пролиферации клеток ретикулоэндотелиальной системы.

In the conditions of the Republic of Belarus there was determined the parasitizing influence of Oesophagostomum and their larvae on a metabolism of experimentally infested animals. In course of the study there were generated experimental and control groups of two-month old piglets. Animals of the experimental group were infested in a dose of 15000 invasion larvae per one kg of body weight. Animals of the control group were not infested. Infestation was realized through a mouth with invasion larvae with wet forage. Invasion larvae received by cultivation of excrement tests from infested pigs at temperature of 24 deg C. As a result of the realized research it was established, that Oesophagostomum invasion rendered a substantial influence on the experimental animals. At bimestrious pigs after the experimental infection with Oesophagostomum larvae there were stated the following changes: the disease on 4-30th day was characterized by frustration of function of a gastroenteric path - diarrhea, fever, anaemia, and in the subsequent - stagnation and juvenilism of animals. Oesophagostomum in a host organism caused the pathological changes of haemotological and biochemical blood value which were expressed in quantity decrease of erythrocytes, concentration of haemoglobin, leucocytosis. Eosinophilia was observed in a leukogram. In blood serum there was stated the lowering of crude protein and its fractions content; gradually, but authentically there was noted the increasing of activity serum glutamic oxalacetic transaminase and glutamic-pyruvic transaminase. Bactericidal and lysozymic activity of blood serum decreased. Activity of alkaline phosphatase increased.

In the conditions of the Republic of Belarus there were analyzed productivity indexes of sows of different families and family groups and their compatibility with male pigs of different lines of Belarusian meaty breed and Landras. On the basis of the realized research it was marked, that according to the number of piglets in a litter and multiple pregnancy distinctions between breeding sows of Landras breed and Belarusian meaty there was not observed. From sows of both breeds in average per farrowing there was obtain 11,0 - 11,2 piglets, including 10,4 - 10,5 live piglets, that exceeded requirements of the first class of the instruction on evaluation of pigs on 4,0 - 5,0%. At the same time, sows of the Belarusian meaty breed had litter weight at weaning in 40 days of 104 kg, that was authentically higher on 8 kg or on 8,3% (Р less than 0,001), than sows of Landras breed. In each breed there were some distinctions in sow productivity by families and in breeding with boars of different lines.

In the conditions of the Republic of Belarus there were analyzed the doses and efficiency of application of selenium in composition of a mixed fodder KP-2 in diets of bull calves of at their breeding for meat. In course of the study the was developed a formula of a mixed fodder with various doses (0,1; 0,2; 0,3 mg per 1 kg of a dry matter of a ration) of selenium; there was studied the influence of different selenium doses in mixed fodders on palatability of diets, their digestibility, use of nutritive elements and hematological indexes of animals. Also, there was analyzed the influence of different doses of selenium on bull calves growing intensity. There was given the zootechnical and economic evaluation of usage of selenium for bull calves. Selenium dose of 0.2 milligram per 1 kilogram of dry matter proved to be the most efficient and promoted the increasing of average daily body weight gain on 10.9%.