La grande fréquence des nodules thyroïdiens et la relative agressivité des traitements conventionnels ont motivé l'étude d'une méthode non invasive utilisant des Ultrasons Focalisés (HIFU). Matériel et méthodes : Les HIFU ont été testés initialement sur un modèle de brebis afin de réaliser une lésion thyroïdienne. Ces études animales ont été suivies de trois études cliniques sur des patients porteurs de nodules thyroïdiens. L'appareil utilisé associe un système d'imagerie échographique et un système de tir. Résultats : Le réglage des paramètres de tir et la mise au point de plusieurs prototypes chez l'animal a permis d'obtenir l'autorisation du comité d'éthique pour les expérimentations humaines. Ces essais ont démontré la capacité des HIFU à détruire des nodules thyroïdiens. Le dernier appareil mis au point a obtenu le marquage CE. Conclusion : Cette technique permet de réaliser une nécrose localisée dans un lobe thyroïdien et de détruire des nodules. Ces résultats doivent être confirmés par des études plus larges, mais ont été assez encourageants pour justifier la création d'une entreprise dédiée à la mise au point d'un appareil spécifique en collaboration avec l'INSERM / -

Bactérias lácticas probióticas e peptídeos bioativos são importantes componentes de alimentos funcionais. Neste trabalho, bactérias lácticas isoladas de leite ovino cru e de queijo de ovelha foram identificadas por 16S rDNA como pertencentes ao gênero Lactobacillus e avaliadas quanto ao potencial probiótico. Todas as linhagens demonstraram adequada tolerância ao pH 3,0 e a sais biliares em concentrações de até 0,5%. A linhagem LCN 56, quando exposta ao tratamento de pH 2,0 e pepsina, adicionado de leite desnatado, não teve sua viabilidade reduzida durante 4 horas em função do efeito protetor do alimento. Adicionalmente, propriedades de autoagregação e hidrofobicidade, atividades antioxidante e antibacteriana, e ainda, produção da enzima β-galactosidase foram avaliadas em 12 Lactobacillus e em 2 linhagens de referência. Estas características foram bastante variáveis entre as linhagens, mesmo entre aquelas pertencentes à mesma espécie. Nenhuma das bactérias exibiu todas as propriedades desejáveis, porém dois isolados apresentaram conjuntamente o maior número de atributos funcionais, L. brevis SM-B e L. plantarum SM-I. Com relação aos peptídeos com atividade biológica, extratos aquosos de queijos de ovelha maturados foram avaliados e apresentaram propriedades antioxidantes de sequestro do cátion radical 2,2 azino-bis (3-etilbenzotiazolino-6-ácido sulfônico) (ABTS) e atividade quelante de ferro bastante variáveis, enquanto as análises de poder redutor e substâncias reativas ao ácido tiobarbitúrico (TBARS) apresentaram similaridade para a maioria dos queijos. A atividade inibitória da enzima conversora de angiotensina foi elevada, em contraste à atividade antibacteriana que não foi encontrada em nenhuma das amostras. Os resultados encontrados podem ser atribuídos a possíveis peptídeos bioativos presentes. O perfil proteico do extrato aquoso correspondente ao queijo Roquefort foi visualizado por SDS-PAGE, por ter sido a amostra com a melhor intensidade das bioatividades. Portanto, os resultados refletem a potencial funcionalidade dos produtos lácteos ovinos. / Probiotic lactic bacteria and bioactive peptides are important components of functional foods. In this work, lactic bacteria isolated from raw ovine milk and cheese were identified by 16S rDNA as belonging to Lactobacillus genus and evaluated for probiotic potential. All strains demonstrated appropriate tolerance to pH 3.0 and bile salts until 0.5% of concentration. The strain LCN 56, when exposed to the treatment of pH 2.0 and pepsin added with skim milk, did not reduce viability during 4 hours due to protective effect of the food. Additionaly, autoaggregation and hydrophobicity properties, antioxidant and antibacterial activities and also β-galactosidase production were evaluated for 12 lactobacilli and for 2 reference strains. These characteristics were quite variable among strains, even among strains belonging to the same species. None of them exhibited all the desired properties, but two strains showed the greatest number of functional attributes together, L. brevis SM-B and L. plantarum SM-I. In relation to peptides with biological activity, water soluble extracts of ewe´s ripened cheeses were evaluated and presented antioxidant properties of scavenging of the cation radical 2,2‘-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and iron chelating activity quite variable, whereas power reduction and thiobarbituric acid reactive substances (TBARS) analysis presented similarity for the major of the cheeses. Inhibition of the angiotensin-converting enzyme (ACE) was elevated, in contrast to antibacterial activity that was not found for any sample. The results found can be attributed for the possible presence of bioactive peptides. The protein pattern of water soluble extract corresponding to Roquefort was visualized by SDS-PAGE for being the sample that displayed the best bioativities. Therefore, the results reflect potential functionality of dairy sheep.

Com o objetivo de avaliar a relação entre o exame físico da glândula mamária de ovelhas com o leite, 292 ovelhas da raça Santa Inês foram examinadas. As amostras de leite foram submetidas ao exame bacteriológico, ao CMT e a CCS (automática e microscópica). Variações especificamente identificadas por inspeção da mama apresentaram alterações de celularidade observadas pelo CMT (p<0,002), na CCS automática (p<0,006), e na CCS microscópica diferencial para células mononucleares (p<0,03). Mamas pendulosas puderam ser associadas a maior isolamento bacteriológico (p<0,0006) e maior celularidade nas CCS automática (p<0,01) e microscópica (p<0,05). Na inspeção do teto foram encontradas diferenças no exame da CCS automática (p<0,002), no CMT (p<0,004) e na CCS microscópica diferencial para células mononucleares (p<0,005). Nos tetos com soluções de continuidade, foram observadas diferenças apenas no exame bacteriológico (p<0,03). Quanto à palpação da mama, foram observadas diferenças no exame bacteriológico (p<0,001), no CMT (p<0,01) e na CCS microscópica total (p<0,02) e diferencial para células polimorfonuleares (p<0,02) e para células mononucleares (p<0,0002). Quanto à palpação do teto, foram encontradas diferenças no CMT (p<0,01) e na CCS microscópica total (p<0,002) e diferencial para células polimorfonucleares (p<0,002) e para células mononucleares (p<0,002). Associando-se a inspeção à palpação das metades mamárias, observou-se diferenças na CCS automática (p<0,0002) e na CCS microscópica total (p<0,04) e diferencial para células mononucleares (p<0,01). No exame do fundo escuro, foram observadas diferenças no CMT (p<0,0001), na CCS automática (p<0,0001), e na CCS microscópica total (p<0,0001) e diferencial para células polimorfonucleares (p<0,0001) e mononucleares (p<0,0001). Quando associadas duas categorias do exame físico da glândula mamária, a inspeção e a palpação, e o exame do fundo escuro, foram observadas diferenças no CMT (p<0,0001), na CCS automática (p<0,0001) e na CCS microscópica total (p<0,0001) e diferencial para células mononucleares (p<0,0001). Nas ovelhas acompanhadas durante a lactação foram observadas diferenças na inspeção da mama (p<0,0001) e do teto (p<0,0001), na palpação da mama (p<0,005) e do teto (p<0,003), na inspeção e palpação das metades mamárias (p<0,04), na inspeção, palpação e fundo escuro das metades mamárias (p<0,03), na CCS automática (p<0,0001) e na CCS microscópica total (p<0,02) e diferencial para células polimorfonucleares (p<0,02) e para células mononucleares (p<0,02). Foi possível concluir que há relação entre o exame físico e o perfil celular e bacteriológico, mas que a inflamação da mama foi melhor identificada pelo CMT, através da inspeção da mama e do teto, da palpação da mama e do teto, do exame do fundo escuro e da avaliação da inspeção, palpação e fundo escuro das metades mamárias. A inflamação também foi identificada pela avaliação da CCS automática e/ou da CCS microscópica total e/ou diferencial através da inspeção da mama e do teto, pendulosidade da mama, palpação da mama e do teto, inspeção e palpação das metades mamárias, exame do fundo escuro e a inspeção, palpação e fundo escuro das metades mamárias. O processo infeccioso mamário pôde ser identificado através da pendulosidade mamária, presença de soluções de continuidade no teto e pela palpação da mama. A maior celularidade ocorreu no início da lactação. No final da lactação, houve maiores proporções de alterações na inspeção da mama e do teto e na palpação do teto. Nas fases intermediárias da lactação, as alterações na inspeção e palpação associadas e na inspeção, palpação e fundo escuro associados foram menores. / The aim of this work is to evaluate the relationship between the mammary gland physical examination of ewes and their milk. 292 ewes of Santa Inês breed were evaluated, and the milk samples were submitted to bacteriological examination, to CMT (California Mastitis Test), to automatic SCC (somatic cell count) and microscopic SCC. Specifically identified variations during the mama inspection had cellular alterations, observed in CMT (p<0,002), in automatic SCC (p<0,006) and in differential microscopic count for mononuclear cells (p<0,03). Pendulous mamas could be associated to the largest bacteriological isolation (p<0,0006) and the largest cellular in automatic SCC (p<0,01) and microscopic SCC (p<0,05). In the teat inspection, differences were found in the automatic SCC (p<0,002) in the CMT (p<0,004) and in differential microscopic count for mononuclear cells (p<0,005). In the teat with lesion, differences were observed only in bacteriological examination (p<0,03). In mamma palpation, there were observed differences in bacteriological examination (p<0,001), in CMT (p<0,01), in total microscopic count (p<0,02), differences to polymorphonuclear cells (p<0,02) and to mononuclear cells (p<0,0002). In teat palpation, differences were found in CMT (p<0,01), in total microscopic count (p<0,002) and differences to polymorphonuclear cells (p<0,002) and to mononuclear cells (p<0,002). Associating the inspection and palpation of mammary gland, differences were observed in automatic SCC (p<0,0002) and in total microscopic count (p<0,04) and differences to mononuclear cells (p<0,01). In tamis exam, differences were observed in the CMT (p<0,0001), in automatic SCC (p<0,0001), and in total microscopic count (p<0,0001) and differences to polymorphonuclear cells (p<0,0001) and mononuclear cells (p<0,0001). When the two categories of mammary gland physical exam, the inspection, the palpation, and the tamis exam were associated, there were observed differences in the CMT (p<0,0001), in the automatic SCC (p<0,0001) and in the total microscopic count (p<0,0001), and differences in the microscopic SCC to mononuclear cells (p<0,0001). In the ewes followed during the lactation there were differences in mamma inspection (p<0,0001), in teat (p<0,0001), in mamma palpation (p<0,005) and in teat (p<0,003), in the inspection and palpation of mammary gland (p<0,04), in inspection, palpation and tamis exam of mammary gland (p<0,03), in automatic SCC (p<0,0001) and in total microscopic count (p<0,02), and differences for polymorphonuclear cells (p<0,02) and to mononuclear cells (p<0,02). It can be concluded that there is a relationship among the physical exam and the cellular and bacteriological profile, but the mamma inflammation was better identified by the CMT, through inspection of mamma and teat, and mamma and teat palpation, and tamis exam and the evaluation by inspection, palpation and macroscopic assessment of the milk by mammary glands. The inflammation was also identified by the evaluation of automatic SCC and/or total microscopic count through inspection of mamma and teat, pendulous mamma, palpation of mamma and teat, inspection and palpation of mammary gland, tamis exam and the inspection, palpation and tamis exam of mammary gland and milk. The infection in mammary gland can be identified by pendulous mamma, lesion in teat and by palpation of mamma. The biggest cellular was found in early lactation. And in late lactation, there were found more alterations in mamma and teat inspection and palpation of teat. In the intermediate phases of lactation, the alterations in inspection and palpation associated and the inspection, palpation and the tamis exam associated were smaller.

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.

Protestant missionaries from northern Germany began work in the Ewe-speaking area of West Africa (today divided between southwestern Togo and southeastern Ghana) in 1847. This guide is based on notes made by Rainer Alsheimer, with the addition of an index and a preface.

Pregnancy toxaemia (ketosis) is a metabolic disease of ewes which occurs during the late gestation as a result of the inability of the pregnant ewe to maintain an adequate energy balance for the fast growing maternal fetal unit. As a result of energy defi-ciency mobilization of lipid reserves results in a doubling of the plasma free fatty acid (FFA) giving rise to fatty liver and increased ketone bodies β-hydroxybutyrate (BHB) in blood and urine. It is associated with a higher rate of mortality and causes severe economic losses. The objective of this study was directed at investigating the relationship between metabolic parameters and cytokine TNFα, to check the interaction between the TNFα and fat metabolism in late pregnant ewes of different breeds, and whether TNFα play a role in the pathogenesis of pregnancy toxaemia, which may serve as marker to early diagnosis of the disease. In this study, 29 pregnant and clinically healthy ewes (16 Merino, 13 Blackhead) were selected out of a flock of sheep. Blood samples were collected at 5, 3, and 1 week be-fore parturition (b.p.) and also 4 weeks after parturition (a.p.). The average numbers of lambs were 2.18 and 1.58 /ewe for Merino and Blackhead breeds respectively. The blood samples were analyzed for the following:  Concentration of metabolic parameters: glucose, insulin, free fatty acids (FFA), β-hydroxybutyrate (BHB), albumin, total protein (TP), iron (Fe), glutamat-dehydro-genase (GLDH), creatin kinase (CK), gamma-glutamyl-transferase (GGT), choles-terol, haptoglobin.  Haematological parameters: Haematocrite (HK), haemoglobin concentration (HB), erythrocyte count (EC), leukocyte count (LC), mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC).  Cytokine TNFα by using ovine TNFα ELISA assay. The results of glucose concentration of pregnant ewes showed significant increase (3.8 mmol/l) in five weeks b.p. and declined with advancing gestation (2.6 mmol/l) one week b.p. Insulin concentration remained constant with an average of 0.11 nmol/l b.p., and then significantly increased to 0.22 nmol/l four weeks a.p. Maximal FFA concentrations were found at five weeks b.p. (976 µmol/l). The levels of FFA showed high levels b.p. compared with reference range (R.R. < 600 µmol/l), and the FFA levels significantly decreased postpartum (four weeks b.p.). while there was significant increasing (p<0.05) in the level of FFA in Merino sheep than in Black-head sheep b.p. On the other hand there was no significant difference a.p. The mean values of BHB in all periods of sampling, period 1(5 w.b.p.), period 2 (3 w.b.p.), period 3 (1 w.b.p.), and period 4 (4 w.a.p.) were 0.37 mmol/l, 0.23 mmol/l, 0.17 mmol/l and 0.3 mmol/l respectively. The mean of BHB indicated normal levels of BHB before and after parturition compared to subclinical ketosis (BHB > 1 mmol/l) and clinical ketoses (BHB > 1.6 mmol/l), and there was a significant difference (p<0.05) in the values of BHB between Blackhead and Merino breeds before parturi-tion while there was no significant difference after parturition. The concentration of TNFα showed elevated levels in all period of sampling before parturition. The TNFα values were 30.4 (17.2, 785.0) ng/ml (median, first, and third quartiles), 35.6 (13.6, 54.3), and 26.6 (13.0, 39.9) ng/ml in period 1(5 w.b.p.), period 2 (3 w.b.p.), and period 3 (1 w.b.p.) respectively. These values decreased to 19.1 (9.9, 33.8) ng/ml at 4 weeks after parturition. Statistical analysis showed that there was a positive correlation between free fatty ac-ids and TNFα. This correlation means that adipose tissue produces TNFα causing insu-lin resistance, which stimulates the lipolysis and leads to an increase of circulatory free fatty acids levels. It is concluded that fat mobilization occurs in the prepartum clinically healthy ewes with a significant increase in the levels of FFA, and also there is an increase in the proinflammatory cytokine TNFα at late gestation which predisposes ewes to pregnancy toxaemia and can aid in the diagnosis of the disease.:Table of contents 1 Introduction…………….…………………………………………………..1 2 Review of literature……....…………….……………………………….….3 2.1 Metabolic condition of ewes in the late pregnancy………….………………3 2.2 Metabolic disorders subacute and acute pregnancy Toxaemia…….………..4 2.3 The Importance and dynamic of the different biochemical parameters glucose, insulin, free fatty acids, and β-hydroxybutyrate of ewes in the late pregnancy…………………….………..….……………………………10 2.3.1 Glucose……………………………………………………………………..10 2.3.2 Insulin………………………………………………………………………12 2.3.3 β-hydroxybutyrate (BHB)…….……………………………………………16 2.3.4 Free fatty acids……………………………………………………………...20 2.4 TNFα and its role in fat metabolism and pregnancy toxaemia………….….22 3 Animals, material and methods……………………………………..……38 3.1 Animals……………………………………………………………………..38 3.2 Clinical examination………………………………………………………..38 3.3 Collection of blood samples……………………………………………..…38 3.4 Analysis of haematological parameters in blood samples……………….....38 3.5 Determination of biochemical parameters………………………………….39 3.6 Determination of haptoglobin by using haptoglobin assay……………...…39 3.6.1 Haptoglobin assay principle………………………………………………..39 3.6.2 Components………………………………………………………………...40 3.6.3 Additional materials required………………………………………………40 3.6.4 Sample and reagent preparation………………………………….….……..40 3.6.4.1 Samples……………………………………………………………………..40 3.6.4.2 Haemoglobin.................................................................................................40 3.6.4.3 Chromogen/Substrate………………………………………………………40 3.6.5 Manual methods (microplate or spectrophotometric)……………………...41 3.6.5.1 Calibrator…………………………………………………………………...41 3.6.5.2 Test temperature…………………………………………………………....41 3.6.5.3 Procedure………………..………………………………………………….41 3.7 Analysis of TNFα by using ovine TNFα ELISA assay…………………….42 3.8 Statistical analysis…………………………………………………….…….43 4 Results.……………………………………………………………………..44 4.1 Clinical examination (observation)…………………………………….…...44 4.2 Biochemical parameters………………………………………………….…44 4.2.1 Glucose………………………………………………………………….…..44 4.2.1.1 Glucose concentrations in all sheep…………………………..…………….44 4.2.1.2 Glucose concentrations in Blackhead sheep…………………………..…....44 4.2.1.3 Glucose concentrations in Merino sheep………………………...…………45 4.2.2 Insulin……………………………………………………………………….45 4.2.2.1 Insulin concentrations in all sheep………………………………..………...45 4.2.2.2 Insulin concentrations in Blackhead sheep………………………..………..46 4.2.2.3 Insulin concentrations in Merino Sheep…………………………………….46 4.2.3 Free fatty acids……………………………………………………………...47 4.2.3.1 Free fatty acid concentrations in all sheep………………………………….47 4.2.3.2 Free fatty acid concentrations in Blackhead sheep………………………....47 4.2.3.3 Free fatty acid concentrations in Merino sheep………………………….....47 4.2.4 β-hydroxybutyrate (BHB)…….…………………………………………….48 4.2.4.1 β-hydroxybutyrate concentrations in all sheep……..……………………....48 4.2.4.2 β-hydroxybutyrate concentrations in Blackhead sheep……… …………....48 4.2.4.3 β-hydroxybutyrate concentrations in Merino sheep…………………...…...49 4.2.5 Tumor necrosis factor alpha (TNFα)………………….……………….…...50 4.2.5.1 TNFα concentrations in all sheep…………..................................................50 4.2.5.2 TNFα concentrations in Blackhead sheep……………………………….....50 4.2.5.3 TNFα concentrations in Merino sheep………………………………….......51 4.2.6 Haptoglobin………………………………………………………………....51 4.2.6.1 Haptoglobin concentrations in all sheep……………………………..…......51 4.2.6.2 Haptoglobin concentrations in Blackhead and Merino sheep…….………..51 4.2.7 Albumin…………………………………………………………………….52 4.2.7.1 Albumin concentrations in all sheep…………………………..…………...52 4.2.7.2 Albumin concentrations in Blackhead and Merino sheep……………….....53 4.2.8 Creatinkinase (CK)…………………………………………………………53 4.2.8.1 Creatinkinase activity in all sheep………………………………………….53 4.2.8.2 Creatinkinase activity in Blackhead and Merino sheep…………………….53 4.2.9 Gamma-Glutamyl Transferase (GGT)………………………….…………..54 4.2.9.1 GGT activity in all sheep…………………………………………………...54 4.2.9.2 GGT activity in Blackhead and Merino sheep……………………………..55 4.2.10 Glutamat-Dehydrogenase (GLDH)………………………………………...56 4.2.10.1 GLDH activity in all sheep…………………………………………………56 4.2.10.2 GLDH activity in Blackhead and Merino sheep………….…………….......56 4.2.11 Total protein………………………………………………………………..57 4.2.11.1 Total protein concentrations in all sheep………………………………...…57 4.2.11.2 Total protein concentrations in Blackhead and Merino sheep……………..57 4.2.12 Cholesterol……………………………………………………………….…58 4.2.12.1 Cholesterol concentrations in all sheep………………………………...…...58 4.2.12.2 Cholesterol concentrations in Blackhead and Merino sheep…………....….58 4.2.13 Iron………………………………………………………………………….59 4.2.13.1 Iron concentrations in all sheep…………………………...………………..59 4.2.13.2 Iron concentrations in Blackhead and Merino sheep………………….........60 4.3 Haematological parameters………………………………………………...60 4.3.1 Haematological parameters in all sheep……………………………………60 4.3.2 Haematological parameters in Blackhead sheep…………………………...61 4.3.3 Haematological parameters in Merino sheep………………………………61 4.3.4 Statistical analysis of haematological parameters………………………….62 4.3.4.1 Haemoglobin concentration (Hb)…………………………………………..62 4.3.4.2 Haematocrite (HK)…………………………………………………………62 4.3.4.3 Mean corpuscular volume (MCV) …………………………………………62 4.3.4.4 Mean corpuscular haemoglobin (MCH)……………………………………62 4.3.4.5 Mean corpuscular hemoglobin concentration (MCHC)……………………63 4.3.4.6 Thrombocytes volume (THB)……………………..…………………….…63 4.3.4.7 Leukocytes (LC)………..…………………………………………………..63 4.3.4.8 Erythrocytes.……………………………………………………………….63 5 Discussion…………………………………………………………………..65 6 Summary…………………………………………………………………..71 7 Zusammenfassung………………………………………………………...73 8 References…………………………………………………………………75 Acknowledgements.......................................................................................................84

Dois experimentos foram realizados para avaliar o desempenho de ovelhas Santa Inês e mestiças F1 com machos de raças de corte e de suas crias obtidas do cruzamento com carneiros da raça Dorper. No experimento 1, setenta e cinco borregas ( 15 da raça Santa Inês (SI), 15 ½Dorper + ½SI, 15 ½Ile de France + ½SI, 15 ½Suffolk + ½SI e 15 ½Texel + ½SI foram acasaladas com carneiros da raça Dorper e avaliadas quanto ao seu desempenho na parição e lactação. Foram avaliados o número de crias nascidas/fêmea parida, peso de nascimento, % de desmama, consumo de MS das ovelhas, produção e composição do leite, escore de condição corporal, concentração de ácidos graxos não-esterificados e desempenho das crias. A produção de leite foi estimada semanalmente, da segunda à oitava semana de lactação. Os cordeiros foram separados das mães as quais receberam, via endovenosa, 10 UI de oxitocina para permitir a ejeção do leite que foi removido por ordenha mecânica. Após 3h, o procedimento de ordenha foi repetido e a produção de leite foi registrada e uma amostra coletada para posterior determinação da composição. Ovelhas SI apresentaram maior (P<0,05) CMS relativo ao peso corporal do que ovelhas ½DO, ½IF e ½SK. Ovelhas ½DO produziram mais gordura, sólidos totais (ST) e leite corrigido para gordura (LCG) que ovelhas ½IF. Os teores de gordura e de ST no leite das ovelhas ½DO foram maiores (P<0,05) do que no das ½TX. Ovelhas ½TX desmamaram mais kg de cordeiros do que as SI (27,2 kg vs. 17,3 kg). Cordeiros ¼TX apresentaram GMD maior (P<0,05) que os ¾DO (283 g vs. 229 g). No experimento 2, foram avaliados o desempenho e a carcaça de cordeiros mestiços ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) confinados sendo alimentados com ração contendo 90% de concentrado e 10% de feno. Os cordeiros mestiços entraram no confinamento com idade inicial média de 75 dias. Não houve diferença entre as médias de idade ao abate, peso no início do confinamento, peso no abate, consumo de matéria seca, ganho de peso médio diário, eficiência alimentar, peso de carcaça quente, peso de carcaça fria, rendimento de carcaça quente, rendimento de carcaça fria, área de olho de lombo, espessura de gordura subcutânea, alturas torácicas interna e externa, perímetro e comprimento de pernil, espessura de parede corporal, pesos e rendimentos dos cortes cárneos comerciais. Cordeiros do genótipo ¾DO apresentam maior perda por resfriamento de carcaça que os do genótipo ½SI. Cordeiros do genótipo ¼SK apresentam maior comprimento de carcaça que os cordeiros mestiços ¼TX. / Two experiments were performed to evaluate the performance of Santa Inês and F1 crossbred ewes and their lambs obtained by mating the ewes to Dorper rams. In Experiment 1- Seventy-five ewe lambs (15 Santa Inês (SI), 15 ½Dorper+½SI, 15 ½Ile de France+½SI, 15 ½Suffolk+½SI e 15 ½Texel+½SI) were mated to Dorper rams and evaluated during lambing and lactation. Number of lambs born/ewe, birth weight, weaning %, ewess DMI, milk yield, milk composition, body condition score, non- esterified fatty acids and lamb performance were evaluated. Milk production was measured every 7 d, from the second to the eighth week of lactation. Ewes were separated from lambs, oxytocin (10 IU) was infused, i.v., to stimulate milk letdown, and ewes were mechanically milked. After 3 h, the procedure was repeated and milk production was recorded and a sample collected for milk composition analysis. SI ewes showed higher (P<0.05) DMI as % of BW when compared to ½DO, ½IF and ½SK. A higher milk fat, total solids and fat corrected milk was observed for ½DO than ½IF. ½TX ewes produced more kg of weaned lambs than SI (27.2 kg vs. 17.3 kg). ADG for ¼TX lambs was higher (P<0.05) than ¾DO (283 g vs.229 g). In Experiment 2 Forty-eight lambs were used to evaluate the performance and carcass traits. Crossbred lambs were: ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) feedloted and fed diets containing 90% concentrate and 10% hay. Lambs were housed individually and the slaughter target weight was 37 kg. Lambs were 75 days old at begining of the feedlot. There was no difference (P>0.05) on slaughter weight and age, starting weight at feedlot, dry matter intake (DMI), average daily gain (ADG), feed efficiency (FE), hot carcass weight, chilled carcass weight, dressing percentage, Longissimus muscle area, back fat, carcass measures and retail cuts yield. Lambs ¾DO had greater chilling losses when compared to ½SI. Lambs ¼SK showed greater carcass lenght when compared to ¼TX. Crossbred lambs evaluated showed similar performance (ADG, DMI, FE) and carcass characteristics except for carcass lenght. Crossbreeding meat type sheep is an interesting strategy to obtain lambs with desirable performance and carcass quality.

Dois experimentos foram realizados para avaliar o desempenho de ovelhas Santa Inês e mestiças F1 com machos de raças de corte e de suas crias obtidas do cruzamento com carneiros da raça Dorper. No experimento 1, setenta e cinco borregas ( 15 da raça Santa Inês (SI), 15 ½Dorper + ½SI, 15 ½Ile de France + ½SI, 15 ½Suffolk + ½SI e 15 ½Texel + ½SI foram acasaladas com carneiros da raça Dorper e avaliadas quanto ao seu desempenho na parição e lactação. Foram avaliados o número de crias nascidas/fêmea parida, peso de nascimento, % de desmama, consumo de MS das ovelhas, produção e composição do leite, escore de condição corporal, concentração de ácidos graxos não-esterificados e desempenho das crias. A produção de leite foi estimada semanalmente, da segunda à oitava semana de lactação. Os cordeiros foram separados das mães as quais receberam, via endovenosa, 10 UI de oxitocina para permitir a ejeção do leite que foi removido por ordenha mecânica. Após 3h, o procedimento de ordenha foi repetido e a produção de leite foi registrada e uma amostra coletada para posterior determinação da composição. Ovelhas SI apresentaram maior (P<0,05) CMS relativo ao peso corporal do que ovelhas ½DO, ½IF e ½SK. Ovelhas ½DO produziram mais gordura, sólidos totais (ST) e leite corrigido para gordura (LCG) que ovelhas ½IF. Os teores de gordura e de ST no leite das ovelhas ½DO foram maiores (P<0,05) do que no das ½TX. Ovelhas ½TX desmamaram mais kg de cordeiros do que as SI (27,2 kg vs. 17,3 kg). Cordeiros ¼TX apresentaram GMD maior (P<0,05) que os ¾DO (283 g vs. 229 g). No experimento 2, foram avaliados o desempenho e a carcaça de cordeiros mestiços ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) confinados sendo alimentados com ração contendo 90% de concentrado e 10% de feno. Os cordeiros mestiços entraram no confinamento com idade inicial média de 75 dias. Não houve diferença entre as médias de idade ao abate, peso no início do confinamento, peso no abate, consumo de matéria seca, ganho de peso médio diário, eficiência alimentar, peso de carcaça quente, peso de carcaça fria, rendimento de carcaça quente, rendimento de carcaça fria, área de olho de lombo, espessura de gordura subcutânea, alturas torácicas interna e externa, perímetro e comprimento de pernil, espessura de parede corporal, pesos e rendimentos dos cortes cárneos comerciais. Cordeiros do genótipo ¾DO apresentam maior perda por resfriamento de carcaça que os do genótipo ½SI. Cordeiros do genótipo ¼SK apresentam maior comprimento de carcaça que os cordeiros mestiços ¼TX. / Two experiments were performed to evaluate the performance of Santa Inês and F1 crossbred ewes and their lambs obtained by mating the ewes to Dorper rams. In Experiment 1- Seventy-five ewe lambs (15 Santa Inês (SI), 15 ½Dorper+½SI, 15 ½Ile de France+½SI, 15 ½Suffolk+½SI e 15 ½Texel+½SI) were mated to Dorper rams and evaluated during lambing and lactation. Number of lambs born/ewe, birth weight, weaning %, ewess DMI, milk yield, milk composition, body condition score, non- esterified fatty acids and lamb performance were evaluated. Milk production was measured every 7 d, from the second to the eighth week of lactation. Ewes were separated from lambs, oxytocin (10 IU) was infused, i.v., to stimulate milk letdown, and ewes were mechanically milked. After 3 h, the procedure was repeated and milk production was recorded and a sample collected for milk composition analysis. SI ewes showed higher (P<0.05) DMI as % of BW when compared to ½DO, ½IF and ½SK. A higher milk fat, total solids and fat corrected milk was observed for ½DO than ½IF. ½TX ewes produced more kg of weaned lambs than SI (27.2 kg vs. 17.3 kg). ADG for ¼TX lambs was higher (P<0.05) than ¾DO (283 g vs.229 g). In Experiment 2 Forty-eight lambs were used to evaluate the performance and carcass traits. Crossbred lambs were: ½DO + ½SI (½SI), ¾DO + ¼SI (¾DO), ½DO + ¼IF + ¼SI (¼IF), ½DO + ¼SK + ¼SI (¼SK) e ½DO + ¼TX + ¼SI (¼TX) feedloted and fed diets containing 90% concentrate and 10% hay. Lambs were housed individually and the slaughter target weight was 37 kg. Lambs were 75 days old at begining of the feedlot. There was no difference (P>0.05) on slaughter weight and age, starting weight at feedlot, dry matter intake (DMI), average daily gain (ADG), feed efficiency (FE), hot carcass weight, chilled carcass weight, dressing percentage, Longissimus muscle area, back fat, carcass measures and retail cuts yield. Lambs ¾DO had greater chilling losses when compared to ½SI. Lambs ¼SK showed greater carcass lenght when compared to ¼TX. Crossbred lambs evaluated showed similar performance (ADG, DMI, FE) and carcass characteristics except for carcass lenght. Crossbreeding meat type sheep is an interesting strategy to obtain lambs with desirable performance and carcass quality.

This thesis describes a series of four experiments designed to evaluate the role of the supply of protein in livestock grazing high quality pasture during mating and during pregnancy. The first two studies investigated the effects of high crude protein content of spring or autumn re-growth pasture on the reproductive performance of dairy cows and of ewes at mating. The last two studies investigated how the dietary supply of protein, body condition and their interactions contribute to the breakdown of immunity during the peri-parturient period in ewes and investigated underlying endocrine mechanisms. In the first study (Chapter 3) cows were blood sampled via the tail vein during the breeding period in spring. Plasma was then analysed for urea concentration. Cows with high plasma urea (HPU) or low plasma urea (LPU) were defined as those with plasma urea concentrations of ≥ or < 44.9 mg/dl respectively. Lactating cows (n = 200) were also categorized into high milk producers (HMP) or low milk producers (LPM) relative to an average daily yield of 26.6 l/d. Pasture clipping showed an average pasture CP (crude protein) content of 223 g/kg DM. Concentrations of plasma urea ranged from 26.6 to 64.4 mg/dl. No correlation was observed between plasma urea concentration and either reproductive indicators or milk parameters. Mean blood urea concentration of HPU cows was 50.8 compared to 38.5 mg/dl in LPU cows. There was a trend for more animals (P = 0.09) in the HPU group than in the LPU group not to return to oestrus. Cumulative pregnancy rate in HPU and LPU was similar except at week 6 after the start of mating when more (P < 0.01) HPU than LPU cows were pregnant. Calving to conception interval, calving interval and interval between conception and first service were similar (P > 0.05) between HPU and LPU cows. Gestation length, calving rate, milk yield and milk components were also similar (P > 0.05) between LPU and HPU cows. There was no difference (P > 0.05) in plasma urea concentrations between HMP and LMP milk producers. However, calving to conception interval, interval between calving and first service and calving interval were longer (P < 0.001), submission rate higher (P < 0.001) and NRR (Non-return rate) higher (P < 0.05) in LMP than HMP. The number of services, the interval between first and second service, gestation length and CR (calving rate) were similar (P > 0.05) between HMP and LMP cows. HMP had lower (P < 0.001) milk protein and fat concentrations than LMP cows. This information indicates that, despite the fact that plasma urea was consistently higher than levels in the literature which have been associated with reduced fertility in dairy cows; no impairment of reproductive performance was observed. In the second experiment (Chapter 4) mature and dry Coopworth ewes were blocked by weight, body condition and previous prolificacy (high, HP vs low twinning frequency, LP) into two groups and thereafter randomly allocated to diet which were designed to provided either 1) high protein (163 g/kg DM, ryegrass/red clover pasture, HPP) or low protein (119 g/kg DM, hay and barley grain, HB) supply at joining. These were designed to provide high and low plasma urea concentration. Over a period of 17 days, ewes recorded as mated were examined by laparoscopy, at which time there was no difference in blood urea concentration (58.6 vs 56.1 mg/dl) between HPP and HB groups. Fifty days after the start of joining the number of foetuses present was counted using ultrasonography. As a consequence of lack of difference in the plasma urea concentration, irrespective of treatment group, individual animals were categorized into high (HU) and low plasma urea (LU) status based on whether plasma urea concentration was higher or lower than the sample mean of 51.5 mg urea/dl. Lambs which weighed greater than the mean plus one standard deviation for their litter size were classified as oversize. Ovulation rate and conception rate were similar (P > 0.05) between HPP and BH and between HU and LU ewes. Ewes with previous high reproductive performance (HP) as would be expected had higher ovulation rate (P < 0.001) and conception rate (P < 0.01) than LP ewes. Embryo losses was not (P = 0.06) different between HB and HPP ewes. Urea category (HU vs LU) did not (P > 0.05) influence embryo mortality. Foetal loss, neonatal loss, total reproductive loss and mean lamb birth weight was were not affected by diet, nor urea category (P > 0.05). Single ovulations had tended (P = 0.08) to contribute to higher embryo loss compared to multiple ovulations, and, single foetuses suffered higher (P<0.001) losses compared to multiples. While the study did not achieve large differences in plasma urea concentrations between diets, the levels of plasma urea operating were high yet reproductive wastage rates were similar to those recorded in the literature. Together with similar apparent lack of effect on a high plasma urea environment, the data suggest either that previous findings from controlled studies have a more complex aetiology or that pastoral animals can adapt to high tissue ammonia/urea status. The third trial (Chapter 5) was designed to provide information on the supply of amino acids to the abomasum from protein supplementation which have previously been found to overcome dietary scarcity associated with limitation of peri-parturient increase in FEC. Twin-suckling ewes were fitted with rumen and abomasal cannulae and grazed a ryegrass/clover sward (C) or the same sward but with a 500 g/h/d protein supplement (S). The trial was designed as a cross-over with two 14 day adaptation periods followed by two five-day digesta-sampling periods. All ewes were treated with anthelmintic 14 days after lambing. Weekly analysis of blood glucose was carried on whole blood and analysis of amino acids in plasma. The flows of amino acids (AA) and dry matter (DM) at the abomasum were measured during both sampling periods using intra-ruminally infused markers. Live weight and faecal egg count (FEC) were recorded weekly. Diurnal variation in AA flow at the abomasum peaked between 12:00 and 15:00 h and was greatest in S ewes. Flows of AA, including DAPA, were increased by supplementation by 16%, while sulphur amino acids (SAA) were the most enhanced (by 21%) and flows of leucine, lysine, glutamine and aspartate were increased by about 20%. There were significant time effects in rumen and abomasal pH (P < 0.01; in both cases in both periods) reflecting increase in pH after 09.00 h. During Period II, rumen pH in digesta of C ewes was significantly higher (P < 0.001) than that of S ewes (6.7 ± 0.05 vs 6.4 ± 0.05 for C and S ewes, respectively). Plasma AA concentrations (P < 0.01) were lower in S ewes 21 days after parturition, but similar (P > 0.05) to those of C ewes at other times. Forty-three days after lambing (after cross over), the order was reversed as plasma methionine and cysteine concentrations of C ewes became low (P < 0.05). These changes in plasma AA were accompanied by changes in body condition score between day 23 and 70 post-partum whereby C ewes lost more body condition than S ewes. There was evidence for a lower FEC in S ewes, being 46 vs. 670 epg, respectively for S and C groups (P = 0.08) 21 days after anthelmintic treatment. There were higher (P < 0.05) blood glucose levels in C compared to S ewes at day +35 relative to lambing which was reversed and significantly higher (P < 0.01) for S ewes by day +56 from lambing (after treatments were reversed). There was no significant effect of treatment on live weight and lamb performance. There are limited data in amino acid supply on lactating ewes on pasture and the present study contributes additional information on the supply of amino acids at the abomasum. The prediction that flow rates that sulphur amino acids may have been enhanced to the greatest degree could be significant since sulphur amino acids are needed for the synthesis of glutathione for immune response. It can be calculated that supplementation to supply the quantities of S-amino acid at pasture would be needed, since it would not be possible for sheep to increase pasture intake to achieve similar S-amino acid flow. Increase in bypass amino acids in S ewes at certain times in the day probably suggests influence by protein supplementation at certain times of the grazing cycle. Reduced plasma free amino acids at day +21 relative to lambing, may indicate sparing of body protein breakdown by protein supplementation. However, the difference in blood glucose on day 35 and day 56 may indicate re-adjustment of hormonal settings, responsible for nutrient partitioning. The last study (Chapter 6) used ewes during the peri-parturient period on pasture. Eighty pregnant ewes were allocated into four groups balanced for anticipated number of lambs. Group 1 had a high body condition score (BCS) of 4.0 which was maintained throughout pregnancy by pasture allowance (HM; n = 20). Group 2 (n= 40) had medium body condition (BCS 3.0) and were split into two subgroups; one was offered pasture to allow gain of condition (MH; n = 20) and the second allowed to lose condition by offering a low grazing allowance (ML; n = 20). Group 3 were thin ewes (BCS 2.4) and pasture allowance was designed to maintain this condition (LM; n = 20). These feeding regimes were maintained for 3 weeks from week -8 of pregnancy. During week -5 to -4 all ewes were acclimatized to a protein supplement (60 g/d). A glucose tolerance test (GTT) was conducted during week -4 after which half of the ewes in each group were offered a protein supplement at the rate of 500 g/d, creating –S and –NS groups. During wk -2, a second GTT was carried out. Animals were treated with an anthelmintic 3 wks before lambing, and were then challenged with a dose of 10 000 Teladorsagia circumcincta larvae on weeks -2 and -1 relative to lambing. Weekly recording of FEC, live weight and body condition was carried out. Lambs were weighed within 24 h of birth and again at 44 and 65 d of age. Computed tomography body scanning was carried out on ewes at weeks -8, -3 and +8 relative to lambing. There were no differences (P > 0.05) in lamb performance due to body condition or protein supplementation. FEC of all groups was low (≈ 9 peg) and there was no (P > 0.05) significant difference between ewes of different body condition or due to effects of protein supplementation. Ewes bearing/bearing multiple lambs had the highest FEC at day -32 and +12 relative to lambing, which was significant (P < 0.05) on the latter date. There were no significant effects of supplementation on parasite status. There were differences in basal plasma glucose concentration between groups (P < 0.001), being highest in HM/S and least in ML/NS ewes and was generally higher (P <0.001) during GTT 2 than GTT 1. Ewes carrying a single foetus had higher (P <0.001) basal glucose than those carrying multiple lambs (2.2 vs. 1.7 mmol/L, respectively). Other plasma glucose response indexes were similar (P <0.05) between groups. There were differences in insulin responsiveness between groups (P < 0.001), being highest in MH/S and least in ML/S ewes. Insulin responsiveness tended (P = 0.06) to be lower during GTT 1 than GTT 2, but was higher (P < 0.01) in ewes carrying singles than multiples. There was tendency for higher though non-significant, basal insulin concentrations in HM ewes. Insulin trends over time after glucose infusion suggest greater insulin response at GTT 1. Basal insulin was not correlated with CT muscle weight. Despite differences in body muscle mass at the start of the trial and differences induced by nutrition during late pregnancy, positive gains in muscle mass occurred during early pregnancy and muscle mass was similar in all groups by day 56 of lactation. Animals with greatest fat content at parturition (HM) mobilised the greatest amount and those with least fat (LM) deposited fat during lactation. Further experimentation may consider the use of the hyperinsulinemic-euglycemic clamp approach to more precisely estimate whether hormonal re-setting through insulin resistance may be involved in relaxation of immunity during the peri-parturient period.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Growth dynamics of Italian ryegrass (Lolium multiflorum Lam) under different grazing intensities were studied, using marked tillers. The experimental design was completely randomized, with four repetitions (transects) and three treatments consisting of grazing intensities: High , Mean and Low , corresponding to the disappearance of 61.0, 43.3 and 21.1% of the initial forage mass value, respectively. The experimental animals were ewe lambs; rotational grazing was used and the thermal sum of 313 degree-days determined the interval among grazing periods. Grazing intensities affected the morphogenesis and structure of Italian ryegrass only in the period from 24/07 to 02/09. During this period, the Italian ryegrass in the Mean grazing intensity had the lowest leaf appearance rate and leaf elongation rate and it had the highest values of leaf life span. The pseudostem height, the length of the intact and defoliated blades, the number of intact and senescent leaves were higher in Low intensity, and did not differ between Mean and High . In Low intensity, the highest growth and senescence flows were registered, respectively, 85.6 and 54.6 kg/ha day of dry matter (DM). In Mean and High intensities, the growth and intake flows were higher in the beginning of pasture utilization and the senescence flow increased during the Italian ryegrass growing season. The choice of the grazing intensity should be based on the aim of management: when the intention is to prioritize individual weight gain, it is recommended the adoption of the intensity of 43.3%, which allows greater intake of blade s leaf by lambs; but when the objective is to prioritize production per area, it is recommended to use the grazing intensity of 61.0%, because under this intensity Italian ryegrass allows higher stocking rate values. / Estudou-se a dinâmica de crescimento de azevém (Lolium multiflorum Lam.) sob diferentes intensidades de pastejo, por meio de perfilhos marcados. O delineamento experimental foi inteiramente casualizado, com quatro repetições (transectas) e três tratamentos constituídos por intensidades de pastejo: Alta , Média , Baixa , correspondentes ao desaparecimento de 61,0; 43,3 e 21,1% do valor da massa de forragem inicial, respectivamente. Os animais experimentais foram cordeiras, o pastejo foi rotativo e a soma térmica de 313 graus-dia constituiu o intervalo entre pastejos. As intensidades de pastejo afetaram a morfogênese e estrutura de azevém apenas no período de 24/07 a 02/09. Nesse período, o azevém, na intensidade de pastejo Média , apresentou as menores taxas de aparecimento e elongação foliar e os maiores valores de duração de vida das folhas. A altura do pseudocolmo, o comprimento de lâminas intactas e desfolhadas, o número de folhas intactas e em senescência foram superiores na intensidade Baixa , sem diferir entre Média e Alta . Na intensidade Baixa observaram-se os maiores fluxos de crescimento e senescência, respectivamente 85,6 e 54,6 kg/ha/dia de matéria seca (MS). Nas intensidades Média e Alta , os fluxos de crescimento e consumo foram superiores no início da utilização da pastagem, enquanto o fluxo de senescência aumentou ao longo da estação de crescimento do azevém. A escolha da intensidade de pastejo deve ser baseada no objetivo do manejo: quando se objetiva priorizar o ganho de peso individual, recomenda-se a adoção da intensidade de 43,3%, que permite maiores consumos de lâminas foliares por cordeira; já quando se objetiva priorizar a produção por área, recomenda-se a utilização da intensidade de pastejo de 61,0%, pois sob essa intensidade o azevém permite maiores valores de taxa de lotação.