Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The objective of this study was to evaluate whether supplementation with calcium salts of fatty acids (CSFA) during to pre and/our postpartum affects production and composition of milk, metabolites blood, productive and reproductive performance from beef cows of different genetic groups maintained on native pasture, and performance of this calves. Were used 86 of crossbred Charolais Nellore cows, distributed into the following supplement treatments: PRE: supplemented with CSFA during 45 days prepartum; PREPOS: supplemented with CSFA during 45 days prepartum and 63 days postpartum; POS: supplemented with CSFA during 63 days postpartum; PN: without supplementation. The data were submitted to analysis of variance, the model included cow age and birth order as covariates and the effects of supplementation, cow genetic group, period and the interactions among these factors. There was no significant interaction between the factors evaluated. Cows supplemented with fat protected in the prepartum and/or postpartum showed milk production and productions of components of the milk similar. Crossbreed Nellore cows showed milk with higher lactose content. The supplementation with calcium salts of fatty acids during the pre and/or postpartum non affect the metabolites blood from beef cows. The cholesterol content increase and triglycerides and urea decreased linearly until the end of the experiment. The supplementation with by-pass fat non affect the performance of the calves. Adults cows produced calves with superior performance to produced by first calf and young cows until the 7 months of age. Crossbreeds Nellore cows produced calves with average weight daily gain (GMD) superior from 21 to 42 days of age in relation to crossbreed Charolais cows. The supplementation with fat protected in pre and/or postpartum non affect the productive and reproductive performance from cows. The supplementation great the calving interval. Crossbreed Charolais cows showed higher weight and GMD in relation to croosbreed Nellore cows. / O objetivo do experimento foi avaliar se a suplementação com sais de cálcio de ácidos graxos (SCAG) durante o período pré e/ou pós-parto afeta a produção, a composição do leite, os metabólitos sanguíneos, desempenho produtivo e reprodutivo de vacas de corte de diferentes grupos genéticos mantidas em pastagem natural, assim como o desempenho de seus bezerros. Foram utilizados 86 pares de vacas e bezerros, cruzas Charolês - Nelores distribuídas nos seguintes tratamentos alimentares: PRÉ: suplementação com SCAG durante 45 dias antes do parto; PREPOS: suplementação com SCAG durante 45 dias antes do parto e 63 dias pósparto; POS: suplementação com SCAG durante 63 dias pós-parto; PN: sem suplementação. Os dados foram submetidos à análise de variância, quando o modelo estatístico incluiu idade e ordem de parição como co-variáveis e os efeitos da suplementação, grupo genético, período e suas interações. Não houve interação significativa entre os efeitos estudados. Vacas suplementadas com gordura protegida no pré e/ou pós-parto foram similares as vacas não suplementadas quanto à produção de leite e as produções dos componentes do leite. Vacas com predominância de sangue Nelore apresentaram leite com maior teor de lactose. A suplementação com sais de cálcio de ácidos graxos durante o período pré e/ou pós-parto não afetou os metabólitos sanguíneos de vacas de corte. Com o transcorrer dos dias do período experimental, os níveis de colesterol aumentaram e os níveis plasmáticos de triglicerídeos e ureia diminuíram. A suplementação com gordura protegida não afetou o desempenho dos bezerros. Bezerros de vacas adultas apresentaram desempenho superior até o desmame em relação aos bezerros de vacas primíparas e jovens. Bezerros de vacas mestiças Nelore-Charolês apresentaram ganho de peso médio diário superior dos 21 aos 42 dias de idade em relação às Charolês-Nelore. A suplementação com gordura protegida nos períodos pré e/ou pós-parto não afetou o desempenho produtivo e reprodutivo das vacas. O intervalo entre partos foi beneficiado pela suplementação. Vacas com predominância de sangue Charolês foram mais pesadas e ganharam peso mais rápido do que as vacas com predominância de sangue Nelore.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Concerning the milk production chain, the structure of monopsony in the market of factors has its domain for many years in the State of Rio Grande do Sul. It has been verified in the last years especially from 2004 is a significant increase in the amount of the milk processing companies in the North of the State of RS, concentrating in regions which has strong milk basins. This fact provokes, consequently, the increase of the concurrence between these companies in relation of the acquisition of its main raw material, the in-natura milk. It was identified a region in the town of Ajuricaba-RS, where historically just one company was responsible for the purchase of the raw material and, since 2004, several companies dispute for the milk produced in that location. The objective of the present research was to investigate, in this region, how the concurrence in the acquisition of the raw material interfered in the transactions between processing company and farmer and in its domain in the milk productive chain. Based on the characteristics and in the nature of the investigation, this study is embedded in a research of a qualitative sort and utilizes the Study of Case method. The review of the literature (to compose the theoretical corpus of the study), the observation and the interview (to accomplish the field work) was used as research devices. The concurrence in that location brought changes in the people involved. These changes raised the costs of transaction, characterized by a higher frequency in the transactions, caused by the increase of the uncertainty, of the opportunism and consequently making a more limited rationale. Yet the structure of domain adopted in the concurrence ambient, compared to the one adopted in the monopsony ambient, remain it hybrid, but became closer to a via market management. It is asserted second the observation that the price has became the single factor of decision by the dealer to sell its production to one or another purchaser. With any other management strategies previously adopted by the companies not influencing his decision like, for instance, the payment for the milk quality, financings and technical support. Combined to that, a need for a monthly renegotiation of the product occurred, with the elaboration of informal short-term contracts. / A estrutura de mercado de fatores que predominou por muitos anos na cadeia produtiva do leite, nas diferentes regiões do estado do Rio Grande do Sul, foi a de monopsônio, em que apesar de existirem várias empresas processadoras de leite, estas localizavam-se de maneira que o agricultor não tinha mais do que uma opção de venda do seu produto. O que vem sendo observado nos últimos anos, em especial a partir de 2004, é um significativo aumento no número de empresas processadoras de laticínio no Norte do estado do RS, concentrando-se em regiões que possuem fortes bacias leiteiras. Esse fato provoca, conseqüentemente, o aumento da concorrência entre estas empresas na aquisição da matéria-prima principal, que é o leite inatura. Identificou-se uma região no município de Ajuricaba RS, onde, historicamente, apenas uma empresa era responsável pela compra da matéria-prima e, a partir de 2004, várias empresas disputam o leite produzido no local. O objetivo desta pesquisa foi investigar, nesta região, como a concorrência na aquisição da matéria-prima interferiu nas transações entre empresa processadora/agricultor e na governança da cadeia produtiva do leite. Com base nas características e na natureza da investigação, esse estudo se enquadra numa pesquisa qualitativa e utiliza o método do Estudo de Caso. Como instrumentos de pesquisa foram utilizados a revisão de materiais bibliográficos (para compor o corpo teórico do trabalho), a observação e a entrevista (para realização do trabalho de campo). A concorrência no local gerou modificações no comportamento dos agentes. Essas mudanças fizeram com que aumentassem os custos de transação, caracterizados pela maior freqüência nas transações, pelo aumento da incerteza e do oportunismo. Já a estrutura de governança adotada no ambiente de concorrência, comparada à adotada no ambiente de monopsônio, continuou híbrida, mas ficou mais próxima de uma governança via mercado. Afirma-se isso, visto que o preço tornou-se o único fator de decisão do fornecedor de vender sua produção para um ou para outro comprador. Não tendo influência na sua decisão outras estratégias de governança adotadas antes pelas empresas, como, por exemplo, o pagamento pela qualidade do leite, financiamentos e assistência técnica. Combinado a isso, surgiu a necessidade de renegociação do produto mensalmente, com a elaboração de contratos informais de curto prazo.

Foram realizados dois experimentos visando avaliar diferentes estratégias de vedação para silos do tipo trincheira. No experimento I, objetivou-se avaliar as características fermentativas, composição química e perdas de matéria seca e de matéria orgânica em silagens de milho vedadas com diferentes tipos de filmes plásticos e com ou sem a adição de camada de bagaço de cana. Os tratamentos utilizados foram: ETNC: filme dupla face de polietileno com 200 ?m de espessura; ETC: filme dupla face de polietileno com 200 ?m de espessura recoberto com camada de 10 cm de bagaço de cana e ET+ADNC: filme co-extrusado dupla face de poliamida e polietileno, com 120 ?m de espessura. O delineamento experimental foi de blocos casualizados. Os dados foram submetidos à análise de variância e suas médias foram comparadas pelo teste Tukey, a 5% de signigicância. A quantidade de silagem deteriorada foi menor para o tratamento ETC, enquanto que os demais tratamentos foram semelhantes entre si. Não foi observada diferença significativa entre os tratamentos para a composição bromatológica, entretanto, observou-se diferença para entre os diferentes pontos amostrados (TL: topo lateral, TC: topo central e C: centro) para as variáveis MS, FDA, amido, hemicelulose e DVIVMO, sendo que os piores resultados foram encontrados nas regiões periféricas (TL e TC) dos silo. Os tratamentos não influenciaram na contagem de microrganismo (BAL: bactérias ácido láticas, FF: fungos filamentosos e LEV: leveduras), porém, com relação ao local de coleta houve diferença para BAL e FF. Como esperado, a população de FF foi maior na periferia dos silos, enquanto que a de BAL foi maior no centro. A contagem de leveduras não sofreu influência do tratamento e local de amostragem. No experimento II, objetivou-se avaliar o desempenho animal em função da estratégia de vedação de silagens de milho. Foram utilizadas 15 vacas distribuídas aleatoriamente em cinco quadrados latinos 3x3, com períodos de 21 dias. Os animais foram mantidos em sistema de confinamento Tie-Stall com baias individuais e alimentadas duas vezes ao dia. Os tratamentos foram definidos de acordo com o método de vedação: ETNC, ETC e ET+ADNC. As dietas foram formuladas para serem isoproteicas, com 53% de silagem de milho (% MS). As porções deterioradas das silagens foram descartadas diariamente, as rações foram preparadas utilizando apenas silagem não deteriorada. O consumo de matéria seca, a produção e composição do leite foram determinados entre os dias 15 e 21 de cada período experimental. Os dados foram analisados utilizando o Proc Mixed, do software estatístico SAS. Os tratamentos ET+ADNC e ETC apresentaram maior eficiência energética enquanto que os tratamentos ET+ADNC e ETNC tiveram tendência de maior produção de leite corrigido para 3,5% de gordura e excreção de energia no leite; da mesma forma, a excreção de proteína no leite também foi aumentada. O tratamento ETC não promoveu melhoras no valor nutritivo das silagens, enquanto que os tratamentos ET+ADNC e ETNC apresentaram tendência em maximizar o desempenho das vacas. / Two experiments were conducted to evaluate different strategies to cover silos. The experiment I evaluate the chemical fermentation profile, chemical composition and losses of dry matter and organic matter in corn silage covered with different types of plastic film and with or without the added layer of sugarcane bagasse. The treatments were: ETNC: 200?m black-on-white polyethylene film; ETC: black-on-white polyethylene film plus sugarcane bagasse over the film and ET+ADNC: 125?m polyamide/polyethylene coextruded film. The experimental design was randomized blocks. The data were subjected to analysis of variance and their means were compared by Tukey test at 5% significance. The amount of spoiled silage was lower for treatment ETC, while the other treatments were similar. There was no significant difference between treatments for the chemical composition, although differences were observed between different sampling sites (TL: side wall, TC: top center and C: bottom) for the variables DM, ADF, starch, hemicellulose and IVOMD, while the worst results were found in the peripheral regions (TL and TC) of the silo. Treatments did not affect the count of microorganisms (BAL: lactic acid bacteria, FF: filamentous fungi: LEV: yeasts), however the FF acount was greater in the TL and TC, while BAL was higher in the C. The yeast count was not influenced by treatment or sampling site. In the experiment II was evaluated performance of dairy cows fed corn silage covered with different sealing strategies. Fifteen lactating cows were randomly assigned to 5 replicated 3×3 Latin square design with 21-d periods. Animals were housed in sand-bedded tie-stall barn and individually fed ad libitum to achieve approximately 10% refusals twice daily. Treatments were defined according to the method of sealing: ETNC, ETC and ET+ADNC. Diets were formulated to be isonitrogenous with 53% corn silage (DM%) to meet the nutrient requirements of a dairy cow producing 35 kg×d-1 of milk. The deteriorated inedible silage was discarded every day and only edible silage was used to prepare the total mixed rations. Dry matter intake (DMI) and milk yield were recorded from d-15 to d-21 in each period, as well milk composition. Data were analyzed using the Mixed procedure of SAS. Treatments ET+ADNC and ETC showed higher energy efficiency while treatments ET+ADNC and ETNC tended to higher milk yield and energy excretion in milk, as well the excretion of protein in the milk was also increased. Contrary to expected, the ETC treatment did not improve the nutritive value of silages. In conclusion, treatments ET+ADNC and ETNC tended to maximize the performance of dairy cows.

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.

Gli allevamenti di vacche da latte puntano alla massimizzazione della produzione di latte credendo di migliorare così il profitto attraverso l’effetto di diluizione dei costi di mantenimento. Diventa però importante avere sotto controllo i costi di produzione, ma soprattutto la reale efficienza aziendale. Il principale obiettivo di questo lavoro di ricerca è quello di trovare un sistema di monitoraggio dell’efficienza aziendale, sia economica che nutrizionale, utile per i tecnici che visitano le aziende zootecniche di vacche da latte per poter supportare le scelte imprenditoriali dell’allevatore. Sono stati misurati indici tecnici ed economici in 90 allevamenti di vacche da latte per valutare l'efficienza nutrizionale ed economica degli allevamenti. Un approccio multivariato è stato utilizzato per aggregare gli indicatori parziali in nuove strutture latenti. Un secondo obiettivo è stato quello di predire, attraverso le caratteristiche aziendali ed altre informazioni relative alla gestione dell’azienda, gli indici aggregati di efficienza aziendale ricavati, ovvero: efficienza economica, efficienza energetica e punto di pareggio. Ottantanove aziende di vacche da latte sono state visitate e intervistate per raccogliere informazioni sulla consistenza della mandria, la produzione e la qualità del latte, le prestazioni riproduttive, il benessere delle vacche allevate, la formulazione della dieta e i costi di alimentazione. Infine sono state caratterizzare le diverse strategie alimentari adottate nelle aziende visitate. Sono state raccolte informazioni sulle performances della mandria, sui costi di alimentazione e sulle differenti razioni formulate. Sono state caratterizzate la composizione chimica delle diete, il profilo fermentativo delle diete e la produzione di metano, l'efficienza alimentare della mandria, la produzione e la qualità del latte e il profilo fermentativo fecale. / Dairy cow farms aim to maximize milk production believing that this will improve profit through the dilution effect of maintenance costs. However, it becomes important to have under control the feed production costs, but above all the effective business efficiency of whole herd. The main objective of this research work is to find a monitoring system of farm efficiency, both economic and nutritional, useful for technicians who visit dairy farms in order to support the entrepreneurial choices of the farmer. Technical and economic indices were measured on 90 dairy cow farms to assess the nutritional and economic efficiency of the farms. A multivariate approach was used to aggregate partial indicators into new latent structures. A second objective was to predict, through farm characteristics and other farm management information, the aggregate farm efficiency indices derived: economic efficiency, energy efficiency, and break-even point. Eighty-nine dairy cow farms were visited and interviewed to collect information on herd size, milk production and quality, reproductive performance, cow welfare, diet formulation and feeding costs. Finally, the different feeding strategies adopted on visited farms were characterized. Information was collected on herd performance, feeding costs and different formulated rations. The chemical composition of the diets, the fermentative profile of the diets and methane production, feeding efficiency of the herd, milk production and quality and fecal fermentative profile were characterized.

Mastitis is an inflammation that is caused in the udder tissue of cattle and which annually causes high costs within productions and the profitability of farms. The purpose of this study is to determine if udder inflammation affects both the amount of milk that produces and investigate how the protein and fat -content are affected. To be able to implement the study, I have used data from a farm in Värmland where mastitis is a common disease affecting the cows, and which reduces profitability annually. From the year 2015, a total of 134 cows on the farm where the study occurred were treated with antibiotics by a veterinarian, where up to half of the cows were affected by a clinically visible infection. Two groups have been used in the study where 45 cows affected by mastitis have been examined through test milking results and then compared with a control group consisting of healthy individuals where I have used cows that have not been visibly affected by mastitis. The results for the study of how the milk volume is affected showed a significant difference for a decrease in the quantity last year (P =0,036). Based on the results, it is concluded that clinical mastitis reduces the amount of milk and the content of the milk. / Mastit är en inflammation som orsakas i juvervävnaden hos nötkreatur och som årligen orsakar stora kostnader inom produktionen och lönsamheten på gårdar. Syftet med denna studie var att fastställa om juverinflammationer kan påverkar en nedgång inom den mängd mjölk som produceras samt undersöka hur protein- samt fetthalten påverkas eftersom innehållet är en viktig del av lönsamheten. För att kunna genomföra studien har jag använt mig av data från en gård i Värmland där mastit är en vanlig förekommande sjukdom som drabbar korna, och som årligen drar ner på lönsamheten. Från år 2015 har totalt 134 kor på gården där studien genomförts varit behandlade med antibiotika av veterinär där uppemot hälften av korna drabbades av en klinisk synlig infektion. Två grupper har använts i studien där 45 kor drabbade av mastit har undersökts genom provmjölkningsresultat och som sedan jämförts med en kontrollgrupp bestående av friska individer där kor som ej har varit synligt drabbade av mastit använts. Resultatet för undersökningen av hur mjölkmängden påverkas visade en signifikant skillnad för en minskning av mängden sista året (P=0,036) men ingen signifikant skillnad över fett och proteinhalten kunde ses. Utifrån resultatet dras slutsatsen att klinisk mastit minskar mjölkmängden medan innehållet av fett och protein förblir opåverkat.

Bovine somatotropin (bST) is a protein synthesized at the base of the brain and released by the pituitary gland into the circulatory system. BST is transported by the circulatory system and absorbed only by cells of target organs that possess cell surface receptors for the protein (11, 41). Its effect is initiated via a protein receptor initiation and cyclic AMP cascade . This effect on the cell continues well past the degradation of the bST molecule. BST is likely transported into the cell, where it is degraded . Its constituent blocks, amino acids, are used to synthesize new proteins or converted to other metabolites such as sugars (1).

Two studies were conducted during the grazing season of 1997. Study 1 consisted of three Experiments, and the objectives were to compare milk production and composition, body weight change and body condition score, and to determine time patterns of grazing between cows supplemented with different forms and amounts of corn. Also rumen fermentation parameters were measured in cows supplemented with two different types of corn. In study 2, milk yield was measured when grazing pasture was supplemented to lactating Holstein cows fed a typical TMR diet. Predominantly orchardgrass pastures with lesser amounts of white clover and Kentucky bluegrass were grazed during both studies. In Experiment 1, 36 Holstein cows were supplemented either with 6, 6, 6, or 4 kg/d DM of high moisture corn, coarsely ground corn, finely ground corn, or high moisture corn in two equal feedings, respectively. Milk yield was similar (30.3 kg/d) among treatments. Milk protein (2.97%) and MUN (14.7 mg/dl) did not differ among treatments. Body weight change and body condition score change were similar among treatments (23.1 kg and -0.24). During Experiment 2, four rumen-cannulated cows in mid-lactation were supplemented 6 kg/d DM of either coarsely ground corn or high moisture corn in two equal feedings. After the p.m. milking, ruminal pH was measured and rumen fluid samples were collected to determine ammonia N and VFA. While grazing, this was repeated at 0.5, 1, 2, 3,...8 h post-corn feeding (0 h). Ruminal pH was similar for both corn supplements and was lowest (5.9 and 5.8) at 5 and 8 h, respectively. Rumen ammonia N concentrations started to increase approximately 2 h after cows began grazing, reaching maximum levels 5 h later. In Experiment 3, the number of cows grazing, lying, or standing were recorded every half hour, for two consecutive days, while grazing. Cows grazed an average of 6.4 h/d, 4.1 h in the afternoon and 2.3 h in the morning. Similarity in milk production, milk composition, BW change, and BCS between treatments indicates that the quality and availability of pasture permitted equal response regardless of the type or amount of corn supplemented. Fifty four Holstein cows in mid lactation were used in Study 2. Cows were fed either a TMR diet only, or were fed TMR during half of the day (after the a.m. or p.m. milking according to the treatment) and supplemented with grazing pasture during the other half of the day. Milk production was slightly but significantly higher for cows on the TMR treatment (29.1 vs. 28.2 and 27.6). No significant difference between treatments was observed in FCM (27.7 kg/d), and milk fat (3.47) and protein percentage (3.23). While BW change did not differ among treatments (25.7 kg), body condition score increased more in cows fed only a TMR diet (0.14 vs. -0.06 and 0.01). The TMR intake was significantly different between treatments, being highest for cows on the TMR treatment and lowest for cows grazing after the p.m. milking (26.6 vs. 20.3 vs. 17.5 kg/d DM). Income over feed cost differed between treatments, and was approximately 15.3% higher for cows supplemented with high quality pasture during the afternoon compared to cows on TMR. Dairy farmers may obtain economical benefits by practicing this type of management during the grazing season with little effect on milk yield. / Master of Science

Thesis (MScAgric)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: Ruminal pH is the rumen condition that varies most. Studying the cause and effect of diurnal variation offers a means of improving ruminal conditions for rumen micro-organisms with subsequent improvements in fibre degradation, milk yields and milk composition. A research project was conducted to test the following hypothesis: feeding 6 kg (as is) concentrate per cow/day in different weight ratios, divided in a morning and an afternoon allocation, will result in an improved ruminal pH profile and a concurrent increase in fibre fermentation, milk yield and improved milk composition. The project was conducted at the Outeniqua Research Farm in the Southern Cape of South Africa. A randomized block design was used and two phases, viz. ryegrass phase and a kikuyu phase, were applied. Each phase was conducted during the growing season of the grass specie used as pasture. A rumen study and a production study were done in each phase. The rumen study used six cannulated multiparous cows per treatment, testing rumen pH, volatile fatty acid (VFA) concentration, in sacco degradation of neutral detergent fibre (NDF) and dry matter (DM). The production study used 42 multiparous cows, blocked according to days in milk (DIM), parity and milk yield, and cows were randomly divided into three treatment groups. The study tested milk yield, milk composition and changes in body weight (BW) and body condition score (BCS). Treatments consisted of a maize based concentrate supplement (6 kg per cow/day, as is) being fed to cows on pasture in different weight ratios between morning and afternoon allocation. Treatments used in the production study were: Concentrate fed: 5 kg during morning; 1 kg during afternoon • Concentrate fed: 4 kg during morning; 2 kg during afternoon • Concentrate fed: 3 kg during morning; 3 kg during afternoon The first and the last treatments mentioned above were used in the rumen studies. Results of the rumen study of the ryegrass phase showed no differences in ruminal pH between treatment means. The time (h) spent below the critical ruminal pH, i.e. 5.8, was of short duration (2.92 to 3.42 hours). The concentration of certain VFA’s differed at times, but the differences were not reflected in graphs and data of the ruminal pH. No differences were observed in in sacco NDF and DM degradation between treatment means. Similar results were mostly obtained in the kikuyu phase. No differences were found in either daily maximum, minimum or mean ruminal pH between treatment means. Though time (h) spent below the critical ruminal pH was of a long duration (7.1 hours) it did not differ between treatments. No differences were observed between treatment means for in sacco NDF and DM degradation. Results of the production study of the ryegrass phase showed no differences in milk yield or milk composition between treatment means. The same was observed in the kikuyu phase except that milk fat was higher in the treatment group that received the 3:3 kg ratio treatment. The fact that treatments did not differ in terms of milk yield and milk composition in the production studies can be attributed to no differences between treatments in terms of rumen parameters observed in the rumen studies. Thus, feeding a higher proportion of concentrate in the morning relative to the afternoon for a total of 6 kg per cow/day does not affect ruminal pH, fibre digestion or milk production. Based on the results of both phases it can be concluded that the null hypothesis should be rejected. / AFRIKAANSE OPSOMMING: Die invloed van kragvoer voedingsstrategieë op rumen parameters, melkproduksie en melksamestelling van Jerseykoeie op raaigras- (Lolium multiflorum) of kikoejoe- (Pennisetum clandestinum) weidings. Die invloed van kragvoer voedingsstrategieë op rumen parameters, melkproduksie en melksamestelling van Jerseykoeie op raaigras- (Lolium multiflorum) of kikoejoe- (Pennisetum clandestinum) weidings. Behandelings toegepas in die produksiestudie het bestaan uit ‘n kragvoeraanvulling met ‘n mieliebasis wat aan koeie op weidings gevoer is in verskillende gewigsverhoudings tussen oggend- en middagvoeding, as volg: Behandelings toegepas in die produksiestudie het bestaan uit ‘n kragvoeraanvulling met ‘n mieliebasis wat aan koeie op weidings gevoer is in verskillende gewigsverhoudings tussen oggend- en middagvoeding, as volg:

The subject of my thesis was an analysis that deals with the level of nutrition of holstein cattle, witch evaluates feeding, drinking, silage quality techniques and optimalization of the feed ration in 2017 and 2018. In 2017 the feed ration used for dairy cows contained more PDIE. In 2018 the feed ration contained lower amount of energy (6MJ NEL/ 1kg of dry matter) and NL (138,6 g NL/kg of dry matter). After comparing of these two diets for dairy cows with nutrient need, there was recommended an increase of dry matter content in feeding ration. In the milk productivity assessement, the fat and protein content, SC, total aerobic microbial count, was reviewed. The statistic shows the impact of the season of the year on the fat and protein content, SC, total aerobic microbial count in milk. From ecomomy point of view, costs per litre of selled milk was 7,69 Kč in 2017, which was lowered to 7,28 CZK per litre of selled milk. Both years was profitable, and in comparing the economy from 2017 with Czech republic average, tracked stable was more profitable 3 662 CZK per dairy cow.