Serum cortisol and immunoglobulin G (IgG) concentrations were measured to investigate the relationship between vitamin A status and immune function in lambs. Twenty-four crossbred ewe lambs were each fed 900 g·d-1 of a carotene—deficient diet composed of 95.5% whole oats, 3% molasses, .5% trace mineral salt and 1% limestone. All lambs were injected monthly with vitamins D and E and with selenium. The 12 control lambs also received a 100,000 IU oral dose of vitamin A palmitate in capsule form every 2 wk. All lambs were challenged by injecting them with 1 mg ovalbumin in 1 ml of Freund’s complete adjuvant. At the time of challenge, serum vitamin A levels for the control and A-deficient (A—def) lambs were 33.3 and 3.1 ug·dl-1 respectively. Blood was collected prior to and 6, 13, 20 and 34 d post—challenge. The lambs were then reschallenged using the same antigen and blood was obtained 1, 2, 6 and 22 d post—challenge. Lambs were sacrificed at the end of the second challenge period. Spleen weights were obtained and gross post—mortem observations were made at this time. / Master of Science

Antigen-specific and polyclonal serum immunoglobulin G (IgG) concentrations were measured in control (Con), vitamin A-deficient (A-def), and vitamin A-repleted (A-rep) lambs. In Trial, I ewe lambs were injected with primary and secondary antigenic challenges of ovalbumin (1mg) and lysozyme (.1mg). The A-def lambs were then repleted with vitamin A and all lambs were injected with primary and secondary antigenic challenges of human gamma globulin (HGG) (.1mg). In Trial II Con and A-def wether lambs were given primary and secondary antigenic challenges of ovalbumin (20μg). Half of the A-def lambs were then repleted with vitamin A. All lambs were subsequently given a primary and secondary challenge of HGG (20 μg). Spleen wt were similar for all treatments in Trial I while A-def V lambs in Trial II had greater spleen wt (P<.01) than Con or A-rep lambs. Polyclonal serum IgG concentrations were unaffected by treatment in Trial I while in Trial II concentrations were greater (P<.05) in the A-def lambs during the HGG challenge period. Antigen-specific IgG concentrations in both trials tended to be greater in the Con lambs towards the end of both the ovalbumin (Trial I and II) and lysozyme (Trial I) challenge periods. Control and A-rep lambs in Trial I responded similarly to the HGG challenges. In Trial II both the A-def and A-rep lambs had lower (P<.10) HGG specific serum IgG concentrations on the last 3 wk of the HGG challenge period as compared to A-def lambs. Humoral immune function appears to be impaired in A-def lambs and a 2-wk repletion period was not sufficient in this study to restore humoral immune function to normal levels. / Ph. D.

Forty ewe lambs were grouped into four treatment groups: A) fed a standard, high-energy diet, ad libitum; G) fed as group A, but treated with GH (.1 mg/kg bodyweight/d); R) fed the standard diet in restricted amounts to a target weight gain of 120 g/d; S) fed a ration including 30% of a protected fat supplement, ad libitum. Rations were formulated to be isonitrogenous and isocaloric and were fed from approximately seven to 22 weeks of age. Growth rates differed in the order S>A = G> R, although final weights did not differ among ad libitum fed groups. Lambs in group S had heavier mammary glands, with greater amounts of parenchyma and fat pad and higher content of dry, fat-free parenchymal tissue compared to the mean of the remaining groups. Total gland weight was lower in group R, although weight of parenchyma was similar to groups A and G. Parenchyma made up a higher percent of total udder weight in lambs of group R compared to any other group. Parenchymal DNA content was not different by treatment, but glands from group G had twice the total DNA of groups A and R, and group S had 50% more than the latter groups. Volume of mammary glands occupied by parenchyma was increased by more than 50% in group S, compared to the other groups which were similar. Concentrations of prolactin receptors in mammary parenchyma and of GH receptors in liver were increased in lambs of group S. Percent Iinoleic acid in mammary parenchymal lipid of lambs in group S was increased relative to other groups. Unsaturated acids also made up a greater percentage of total fatty acids in group S. Feeding the protected fat supplement resulted in increased unsaturated fatty acid, especially linoleic acid, percentage in mammary fat. This effect was associated with increased mammary growth compared to lambs fed a standard ration. Lambs treated with GH showed some indications of increased mammary growth, but groups A and R were similar except for the increase in percent of gland occupied by parenchyma in group R. In a second study, mammary growth in prepubertal mice increased with increasing dietary energy intake. Differences in ductal growth persisted at 18 weeks of age, and effects of exogenous steroids at this time were not significant. Prepubertal mammary growth in mice is not sensitive to inhibition by high plane of nutrition as is the case in ruminants. / Ph. D.

O caroço de algodão é uma semente oleaginosa e sua inclusão na alimentação de ruminantes pode aumentar os níveis de ácidos graxos insaturados na carne, melhorando os benefícios potenciais da carne vermelha para a saúde. Contudo, como o tipo de dieta pode influenciar o sabor e aroma e a qualidade da carne produzida é possível que a utilização do caroço de algodão em diferentes níveis na dieta de ovinos confinados altere esses parâmetros. Neste experimento objetivou-se estudar o efeito da adição de diferentes níveis de caroço de algodão e do aquecimento do mesmo no desempenho e características da carcaça e da carne de cordeiros confinados após a desmama. Foram utilizados 36 cordeiros cruzados, 16 machos e 16 fêmeas, em um delineamento de blocos casualizados. O aquecimento do caroço de algodão não causou deterioração lipídica na semente. A utilização de caroço de algodão resultou em maior eficiência alimentar e menor ingestão de matéria seca. As dietas experimentais não alteraram as características de carcaça, a maciez objetiva, a cor e as características organolépticas da carne. Quanto ao perfil de ácidos graxos da carne, o caroço de algodão aumentou o teor saturados e diminuiu os monoinsaturados. O colesterol da carne não foi inflenciado pelos tratamentos alimentares. / Whole cottonseed is an oil seed and its inclusion on ruminants diets could alter meat unsaturated fat levels, thereby improving potential health benefits for the consumer. However, diet type could affect taste, flavour and meat characteristics, and there is a possibility of alteration of these parameters when whole cottonseed is included in different levels on the diet. The aim of this experiment was to evaluate the effects of the inclusion of whole cottonseed in different levels in the diet or the heating of this feed, on the performance, meat and carcass characteristics of lambs after weaning. Thirty-six crossbred lambs, sixteen males and sixteen females, were assigned to a ramdomized block design. The heating of the whole cottonseed failed to induce lipidic deterioration of the seed. Whole cottonseed utilization increased feed efficiency and decreased dry matter intake. Meat characteristics like color, objective tenderness, carcass characteristics and sensory qualities were not affected by treatments. Whole cottonseed increased meat saturated fatty acids and decreased monounsaturated fatty acids. Meat cholesterol were not affect by diets.

A utilização de leguminosas na produção de ruminantes pode propiciar benefícios como a melhora no desempenho animal; redução das emissões de metano (CH4), principalmente em razão da presença de taninos; e o aumento na disponibilidade de nitrogênio no solo, devido à fixação deste elemento realizada por estas plantas. A macrotiloma (Macrotyloma axillare - NO 279) é uma leguminosa de clima tropical que se caracteriza por apresentar baixos teores de taninos, com risco reduzido de causar efeitos antinutricionais, mas que ainda carece de estudos a respeito de seus efeitos em ruminantes. Objetivando-se determinar os efeitos dos taninos da macrotiloma sobre a fermentação ruminal in vitro e avaliar a digestibilidade aparente, desempenho produtivo, emissão de CH4, fermentação ruminal, características de carcaça e perfil de ácidos graxos da carne em ovinos alimentados com esta leguminosa, foram realizados os estudos aqui descritos. No primeiro estudo, realizou-se um bioensaio in vitro para se verificar os efeitos dos taninos sobre a fermentação ruminal e produção de gases; e um ensaio in vivo de digestiblidade aparente dos nutrientes, com 12 cordeiras, divididas em 2 tratamentos: dieta exclusiva de feno de gramínea tropical (CON); e dieta de feno de gramínea suplementada com feno de macrotiloma (MAC) (gramínea:leguminosa, 75:25). In vitro, verificou-se menor (p < 0,05) produção total de gases (PTG) e CH4 nas amostras incubadas sem polietilenoglicol (PEG), ou seja, as que estavam sujeitas aos efeitos dos taninos, e no ensaio in vivo, maior digestibilidade da proteína bruta (PB), maior produção de nitrogênio amoniacal (N-NH3) na fermentação ruminal e menor contagem de protozoários ruminais nas cordeiras MAC (p < 0,05) foram observadas. Já no segundo estudo, foi realizado um ensaio de desempenho animal de 90 dias, com 14 cordeiros Santa Inês, divididos em 2 tratamentos, CON e MAC, conforme descrito anteriormente. Neste caso, além do desempenho, também foram avaliados a emissão de CH4 pela técnica do gás traçador hexafluoreto de enxofre (SF6), parâmetros de fermentação ruminal, características de carcaça e perfil de ácidos graxos da carne. Não se observou efeito da macrotiloma (p > 0,05) sobre o consumo de matéria seca (CMS), ganho em peso médio diário (GMD), emissão de CH4, produção de ácidos graxos de cadeia curta (AGCC), características de carcaça e perfil de ácidos graxos. Na avaliação dos parâmetros ruminais, observou-se maior (p < 0,05) concentração de N-NH3 para os animais MAC; maior (p < 0,05) contagem de protozoários nos animais CON; e menor abundância relativa de metanogênicas nos animais MAC (p < 0,05). Mesmo não tendo influenciado o desempenho produtivo e emissão de CH4, as menores produção de CH4 in vitro e contagens de protozoários, a maior produção de N-NH3 e a diminuição das metanogênicas denotaram à macrotiloma potencial como alimento para ruminantes e como alternativa a ser avaliada em novos estudos relacionados à mitigação de CH4 no sistema de produção / Using legumes in ruminant production system may provide benefits such as improvement in animal performance; decrease in methane (CH4) emissions, mainly due to the presence of tannins; and increase in nitrogen soil availability, due to the fixation of this element carried out by these plants. Macrotiloma (Macrotyloma axillare - NO 279) is a tropical legume which is characterized for presenting low concentrations of tannins, providing reduced risks of antinutritional effects, but still has few studies regarding its effects on ruminants. The studies described here aimed to determine the effects of macrotiloma tannins on the in vitro ruminal fermentation, and to evaluate apparent digestibility, productive performance, CH4 emission, ruminal fermentative parameters, carcass characteristics and fatty acids profile of the meat in sheep fed this legume. At the first study, an in vitro bioassay was performed to evaluate gas production and ruminal fermentation, while an in vivo trial was carried out to determine apparent digestibility of nutrients using 12 ewes, divided into 2 treatments: exclusive tropical grass hay diet (control - CON); and tropical grass hay diet supplemented with macrotiloma hay (macrotiloma - MAC) (grass:legume, 75-25). In the in vitro assay, reduced total gases (TGP) and CH4 production were observed in the samples incubated without polyethylene glycol (PEG), that is, those which were subject to effects of tannins (p < 0.05) and in the digestibility trial, increased crude protein (CP) digestibility and ruminal ammoniacal nitrogen (NH3-N), as well as reduced protozoa count were observed for the ewes fed MAC (p < 0.05). In the second study, a 90 days growth performance assay was performed, with 14 Santa Inês lambs divided into 2 treatment groups, CON and MAC, as previously described. In addition to growth performance, CH4 emission by using the sulphur hexafluoride (SF6) tracer technique, ruminal fermentative parameters, carcass characteristics and fatty acids profile of meat were evaluated. No difference (p > 0.05) was observed between the lambs of the groups CON and MAC for dry matter intake (DMI), average daily gain (ADG), CH4 emission, short chain fatty acids production, carcass characteristics as well as for fatty acids profile of meat. Evaluating ruminal fermentative parameters, increased concentration of NH3-N in the rumen fluid and reduction of both, protozoa count and relative abundance of methanogens were observed for the animals fed MAC (p < 0.05) when compared to those fed CON. Even though macrotiloma has not influenced productive performance and CH4 emission, the decrease observed for in vitro CH4 production and in vivo protozoa count, as well as the increased NH3-N production and the reduction in methanogens have denoted potential to macrotiloma as a ruminant feed and as an option for being evaluated in further studies regarding CH4 mitigation in the production system

O objetivo deste estudo foi avaliar o processo de aquisição de anticorpos em cordeiros recém-nascidos aleitados com colostro bovino e ovino, bem como a taxa de proliferação celular no epitélio intestinal. Este estudo contribui com informações sobre a aquisição de imunidade passiva nesta espécie, com o conhecimento do desenvolvimento e maturação do trato gastrintestinal no período neonatal, e para a avaliação de uma alternativa de manejo de colostro para estes pequenos ruminantes. Foram utilizados 30 cordeiros recém-nascidos. Às 0 e 6 horas de vida, 12 animais receberam 250 mL de colostro bovino (grupo CB) e outros 12 animais receberam 250 mL de colostro ovino (grupo CO). Amostras de sangue foram coletadas às 0, 6, 24, e 72 horas de vida para quantificação de imunoglobulina G (IgG) e proteína total sérica (PT). Seis animais foram sacrificados aleatoriamente, logo após o nascimento, sem ingestão de colostro, constituindo o grupo controle. Os demais grupos foram abatido às 24 e 72 horas. Amostras do intestino delgado foram coletadas para a quantificação da taxa de divisão celular nas criptas intestinais. O delineamento experimental adotado foi inteiramente casualizado, sendo as variáveis séricas analisadas como medidas repetidas no tempo. Para a variável histológica foi considerado um arranjo fatorial 2 X 2 + 1, tendo como efeitos principais o colostro fornecido, as idades de abate e o grupo controle. As concentrações de IgG sérica às 6, 24 e 72 horas foram significativamente superiores para o grupo CB (16,58±6,19; 34,12±5,67 e 28,77±5,45 mg mL-1) comparado com CO (10,76±6,08, 20,77±6,53 e 20,25±7,3 mg mL-1). A eficiência aparente de absorção (EAA) da IgG mostrou-se inferior no grupo CB (15,06±4,97%) em relação aos animais do grupo CO (25,70±13,08%). O grupo CB apresentou às 24 e 72 horas maiores (P<0,05) valores de PT (7,29±0,87 e 6,89±0,30 g 100mL-1) em relação ao grupo CO (5,73±1,35 e 5,69±0,57 g 100mL-1). Ao nascimento, os animais apresentaram 32,52%, 45,47% e 30,60% de células em divisão para as regiões do duodeno, jejuno médio e íleo, respectivamente. Às 24 horas, os animais do grupo CO apresentaram menor (P<0,0001) porcentagem de células em mitose no duodeno (42,12%) e no íleo (35,66%) em relação aos animais CB, 46,44% e 39,74%, respectivamente. Às 72 horas, foi observada uma porcentagem menor (P<0,0001) de células em divisão nas criptas do duodeno dos animais CO (36,28%), comparados com o grupo CB (43,18%). Não foi observada diferença significativa entre os tratamentos na porcentagem de células mitóticas nas criptas do jejuno às 24 e 72 horas, bem como nas criptas do íleo às 72 horas (P>0,05). Independente do tratamento, o jejuno foi o segmento com maior (P<0,0001) porcentagem de células mitóticas em todos os períodos. Os valores superiores na taxa de divisão celular no grupo CB indicam que o colostro bovino, provavelmente pela elevada concentração de fatores bioativos e de anticorpos, influencia positivamente o processo de renovação epitelial e que o mesmo pode ser utilizado como fonte alternativa de IgG para cordeiros recém-nascidos. / The objective of this study was to evaluate the antibody acquisition mechanism in newborn lambs fed bovine or ovine colostrum as well as the cell proliferation rate in the intestine epithelium. This study contributes with information about passive immunity acquisition in this specie, with knowledge about development and maturation of the small ruminant intestine tract, and for the evaluations of colostrums management alternative to these small ruminant. Thirty newborn lambs were used. At 0 and 6 hours of life, 12 animals received 250 mL of bovine colostrum (BC group) and another 12 animals received 250 mL of ovine colostrum (OC group). Blood samples were collected at 0, 6, 24, e 72 hours of life for immunoglobulin G (IgG) and total serum protein (TP) quantification. Six animals were randomly slaughtered just after birth, without colostrum intake, constituting the control group. The other groups were randomly slaughtered at 24 and 72 hours. Samples of the small intestine were collected for quantification of cellular division rate in intestinal crypts. A completely randomized desining was used, with the serum variables analyzed as repeated measures on time. For the histological variable it was considered a 2 X 2 + 1 factorial arrangement, having as the main factors colostrum supply, slaughter date and the control group. The IgG serum concentration at 6, 24 and 72 hours were significantly higher for the BC group (16,58±6,19; 34,12±5,67 and 28,77±5,45 mg mL-1) compared with the OC group (10,76±6,08, 20,77±6,53 and 20,25±7,3 mg mL-1). The apparent efficiency of IgG absorption (AEA) were lower for the BC group (15,06±4,97%) in relation to the animals from the OC group (25,70±13,08%). The BC group showed at 24 and 72 hours higher (P<0,05) TP values (7,29±0,87 and 6,89±0,30 g 100mL-1) in relation to the OC group (5,73±1,35 and 5,69±0,57 g 100mL-1). At birth, the animals showed 32,52%, 45,47% and 30,60% cells in division for duodenum, jejunum and ileum, respectively. At 24 hours, the animals from the OC group showed lower (P<0,0001) percentage of cells in mitosis in the duodenum (42,12%) and ileum (35,66%) in relation to the BC animals, 46,44% and 39,74%, respectively. At 72 hours, it was observed lower percentage (P<0,0001) of cells in division in the duodenum crypts of the OC animals (36,28%) compared with the BC group (43,18%). It was not observed significantly difference between treatment in mitotic cell percentage of jejunum crypts at 24 and 72 hours as well as in ileum crypts at 72 hours. Independent of the treatment the jejunum was the segment with higher mitotic cells percentage in all periods. The highest values in cellular division rate in the BC group, probably due to high concentrations of bioactive factors and antibodies, indicates that bovine colostrum influences positively the epithelium renovation process and that it can be used as an alternative source of IgG for newborn lambs.

Experimento I: Foram utilizadas 60 borregas da raça Santa Inês com o objetivo de avaliar os efeitos de três taxas de crescimento até os 7 meses de idade. Os tratamentos foram delineados visando obter alta taxa de crescimento (ATC), moderada taxa de crescimento (MTC) e baixa taxa de crescimento (BTC). Foram avaliados o consumo de matéria seca, o ganho de peso corporal e as concentrações séricas de progesterona para a detecção da idade à puberdade. Foram verificados efeitos lineares (p<0,01) para o peso corporal e metabólico, sendo os maiores valores encontrados para os animais do tratamento ATC. Efeito linear (p<0,01) foi verificado para o ganho médio diário (GMD) sendo de 0,182; 0,156 e 0,136 kg/dia para os tratamentos ATC, MTC e BTC respectivamente. Borregas pertencentes ao tratamento ATC apresentaram maior conversão alimentar sendo os valores para o tratamento ATC de 6,1; MTC de 7,1 e BTC de 9,2 kg MS/ kg de ganho de peso. Verificou-se diferença (p<0,01) quanto a porcentagem de animais que atingiram a puberdade sendo o tratamento MTC com o maior número de borregas púberes até os 7 meses de idade (60%), seguida dos tratamentos ATC (45%) e BTC (15%)com peso médio de 39,3 kg de peso corporal, sendo 70% do peso adulto. Experimento II: As borregas utilizadas no experimento 1 com 37 Kg de PC entraram em estação de monta e após o parto receberam uma única dieta, sendo blocadas de acordo com o peso e dias de lactação. Observou-se efeito quadrático (p<0,01) na produção de leite em 3h (137,9; 150,1 e 104,4 g), efeito quadrático (p<0,05) para LCG (167,2; 178,9 e 129,4) e efeito quadrático (p<0,03) LCGP (216,5; 140,5 e 162,7). Os teores de gordura (9,8; 8,9 e 8,3%) e de proteína (4,2; 4,2 e 4,6 apresentaram efeitos lineares sendo (p=0,01) para gordura e (p<0,01) para proteína. Experimento III: Os objetivos deste experimento foram avaliar o efeito da inclusão de bagaço de cana-de-açúcar in natura (BIN) sobre o consumo e a digestibilidade aparente dos nutrientes, balanço de nitrogênio e os parâmetros ruminais de cordeiros Santa Inês. Quatro cordeiros providos de cânula ruminal com peso corporal (PC) médio inicial de 30kg foram alojados individualmente em gaiolas para ensaios de metabolismo. O tratamento controle positivo (CONT) consistia de uma ração de alto concentrado contendo de 10% de feno de coastcross (Cynodon sp.) na MS, sendo os demais tratamentos níveis crescentes de BIN em 10, 20 e 30% da MS, constituindo os tratamentos 10BC, 20BC e 30BC. As rações experimentais foram isonitrogenadas (13,75±0,25% PB). Não verificou-se efeito de tratamento (p>0,05) sobre o consumo de MS, MO, e PB em kg/dia e g/kg de PC 0,75; apenas sobre consumo de FDN com efeito linear (p< 0,01). O balanço de nitrogênio, assim como a concentração de acetato, propionato, butirato, concentração total de AGCC, amônia no fluido ruminal e a de digestibilidade aparente da MS, MO, PB e FDN não foram afetados pelos tratamentos. / Trial I: Sixty Santa Ines ewe lambs were used to evaluate the effects of three growing rates until 7 months of age. Treatments were defined to achieve high (HGR), moderate (MGR) and low (LGR) growing rates. The dry matter intake and average daily gain (ADG) were evaluated, well as serum levels of progesterone in order to detect the age of puberty. Linear effects (P<0.01) to body weight (BW) with values being 59.5, 61.4, and 58.0 to HGR, MGR and LGR, respectively. Linear effects (P<0.01) was also observed for average daily gain with values being 0.182, 0.156, and 0.136 kg/day, for HGR, MGR and LGR, respectively. The feed:gain ratio showed a linear effects (p<0.02) according to raw sugarcane bagasse inclusion in diet with values being 6.1, 7.1 (M) and 9.2 kgDM/kg BW for HGR, MGR and LGR, respectively. Linear effects (p<0.01) was observed for the percentage of animals of ewe lambs the reached puberty at 7 months of age, showing highest values for MGR (60%), followed by HGR (45%) and LGR (15%) treatment. Trial II: The same ewe lambs of Experiment 1 were bred at 37 kg of BW and after lambing they received a unique diet. The ewe lambs were blocked according to body weight and days in milking. According to the energy density increase in the diet, quadratic effects (p<0.01) was observed on milk production recorded in a 3-hour interval (137.9; 150.1 and 104.4 g), fat corrected milk (167.2, 178.9 and 129.4 g) and fat and protein corrected milk (216.5, 140.5, 162.7g). Fat (9.77, 8.92 and 8.35%) and protein (4.2, 4.2, and 4.6%) showed linear effects (P=0.01) for fat and (P<0.01) for protein. Trial III: The aim of this study was to evaluate the inclusion of raw sugarcane bagasse (RSB) on dry matter intake and apparent digestibility of nutrients, nitrogen balance and ruminal parameters of Santa Ines ram lambs. Four ruminally fistulated ram lambs averaging 30 kg of BW were placed in metabolism crates. The control treatment (CONT) consisted of a high concentrate diet with 10% of coastcross (Cynodon sp.) hay in the dietary DM and the others treatments consisted of 10, 20 and, 30% of RBS in the dietary DM. The diets were formulated to provide similar concentration of crude protein (13.75±0.25%). No effects were observed for DMI, OM, and CP in kg/day and g/kg of BW0.75. Linear effects (p<0.02) was observed for NDF intake according RBS inclusion. Variables, as well as total SCFA, acetate, propionate, and butyrate concentrations. Ruminal ammonia and apparent nutrient digestibility also did not differ among treatments.

Abstract not available

Abstract not available

Temos aktualumas. Avininkystė Lietuvoje yra svarbi žemės ūkio sritis. Šio sektoriaus plėtrai šalyje yra palankios gamtinės sąlygos, susiformavusios gyvulių auginimo tradicijos, sukaupta patirtis. Gyvulininkystės sektorius yra daugiašakė ir įvairiapuse produkcija pasižyminti veikla, reikšminga Lietuvos gyventojams daugeliu ekonominių ir socialinių aspektų. Šis sektorius yra reikšmingas, aprūpinant Lietuvos vartotojus įvairiais maisto produktais bei svarbus Lietuvos eksporto šaltinis. Gyvūninės kilmės produktai yra svarbi subalansuotos mitybos dalis. Juose yra daug žmogaus organizmui reikalingų maisto medžiagų, vitaminų ir mineralų. Lietuvos Respublikos žemės ūkis atlieka svarbią ekonominę, socialinę, gamtosauginę ir etnokultūrinę funkciją, todėl laikomas prioritetine ūkio šaka. Jis pajėgus aprūpinti šalies gyventojus visais kokybiškais maisto produktais ir dalį jų eksportuoti. Nors ir lėtai, avininkystės sektorius plečiasi. Auga mėsos paklausa, atsigauna ir vilnos bei kailių perdirbėjai. Vidutinis avių ūkis Lietuvoje, palyginti su vakarų šalimis, dar yra labai mažas. Dauguma augintojų laiko nedaug avių. O tų žmonių, kuriems avininkystė yra verslas, tėra vos kelios dešimtys. Tačiau mažieji augintojai pamažu didina savo bandas. Įdiegus pažangias intensyvaus avių auginimo technologijas, auginant perspektyvias krypties avių veisles, galima tikėtis šio verslo sėkmės. Darbo objektas: skirtingą skaičių avių turintys ūkiai. Darbo tikslas: išanalizuoti ūkio dydžio įtaką avių... [toliau žr. visą tekstą] / Relevance of the thesis. Shepherding has an important place in Lithuania‘s agriculture. There are suitable enviromental conditions, established cattle herding traditions and accumulated experience needed for this sector‘s further development in the country. The area of animal husbandry is activity known for its multisectoral and multifaceted production, many aspects of which has great economical and social significance for Lithuanians. This area is also very significant when providing Lithuanian consumer with eatables, furthermore it is very important branch of Lithuania‘s export. Products of animal origin takes big part in a balanced diet. They contain many components, vitamins and minerals which human body requires daily. Husbandry has important economical, social, enviromental and ethnocultural function in the Republic of Lithuania, thus it has priority in Lithuania‘s economy. It has capability not only to provide quality eatables for citizens, but also to export some. Sheepherding sector is growing, even though the growth rate is not very pronounced. The demand for meat grows; wool and fur processors are recovering. In Lithuania average sheep farm is very small when comparing with farms in other western countries. Most livestock owners don‘t have a lot of sheep. Furthermore, there are only few who make business out of it. However the small farmers seem to be increasing their flocks. If this business were introduced to advanced sheep herding technologies as well as... [to full text]