Comparison of ruminal microbiota, IL-1ß gene variation, and tick incidence between Holstein × Gyr and Holstein heifers in grazing system.

Introduction: The variation in bacterial communities among breeds has been previously reported and may be one of the reasons why Holstein × Gyr dairy heifers have better development in grazing systems in tropical conditions. This study aimed to explore the ruminal microbiota composition, the IL-1ß gene variation, tick incidence, and blood parameters of Holstein × Gyr (½ Holstein × ½ Gyr) and Holstein heifers grazing intensely managed Guinea grass (Panicum maximum Jacq. cv. Mombaça). Methods: Sixteen heifers were divided into two groups consisting of 8 Holstein × Gyr and 8 Holstein heifers. The experimental period was comprised of 3 periods of 21 days. Ruminal samples were taken via the stomach tube technique. The sequencing of the V4 hypervariable region of the 16S rRNA gene was performed using the Illumina MiSeq platform. Counting and collection of ticks were conducted each 21 days. Blood and skeletal muscle tissue biopsies were performed at the end of the experiment. Results: Firmicutes were the most abundant phyla present in both breed rumen samples and Bacteroidota showed differences in relative abundance between breed groups, with greater values for Holstein heifers (p < 0.05 with FDR correction). The 10 most abundant unique OTUs identified in each breed included several OTUs of the genus Prevotella. Holstein heifers had a greater tick count and weight (9.8 ticks/animal and 1.6 g/animal, respectively) than Holstein × Gyr (2.56 ticks/animal and 0.4 g/animal, respectively). We found nucleotide substitutions in the IL-1ß gene that might be related to adaptation and resistance phenotypes to tick infestation in Holstein × Gyr heifers. Blood concentrations of urea, albumin, insulin-like growth factor 1, triiodothyronine, and thyroxine were greater in Holstein × Gyr than in Holstein heifers. Conclusion: Adaptations in Holstein × Gyr heifers such as ruminal microbiota, tick resistance, nucleotide substitutions in IL-1ß gene, and hormone concentration suggest a better energy metabolism and thermoregulation resulting in better performance in tropical grazing systems.

Association of ionophores, yeast, and bacterial probiotics alters the abundance of ruminal microbial species of pasture intensively finished beef cattle.

The effect of the association of non-protein nitrogen, yeast, and bacterial probiotics on the ruminal microbiome of beef cattle intensively finished on pasture was evaluated. The experiment was carried out in a completely randomized design with five treatments and four replications. The treatments consisted of a group of animals kept on pasture that received low consumption supplementation (LS) and four groups that received for 98 days, 17.5 g concentrate kg-1 body weight. The supplements were composed of the association of additives: urea (U), slow-release non-protein nitrogen (U+SRN), yeast (Saccharomyces cerevisiae; U+SRN+Y), and bacterial probiotics (live strains of bacteria; U+SRN+Y+BP). All supplements also contained salinomycin and virginiamycin. After slaughtering the animals, samples of ruminal content were collected to quantify groups of fibrolytic bacteria (Ruminococcus albus and Fibrobacter succinogenes), non-fibrolytic (Prevotella ruminicola, Selenomonas ruminantium, and Streptococcus bovis), Archaea, and ciliate protozoa, using the qPCR technique. The abundance of F. succinogenes was the same for the LS animals and those that received the supplement U+SRN+Y (1.42×108 copies mL-1) but higher than the other treatments. Supplementation reduced by 90% the abundance of S. bovis compared to the LS. The inclusion of yeast increased the abundance of fibrolytic bacteria by 2.2-fold. For animals that received the supplement U+SRN+Y+BP and the LS, there was no difference for non-fibrolytic bacteria (3.07×109 copies mL-1). The use of yeasts and sources of non-protein nitrogen in high-concentrate diets for beef cattle stimulates the growth of fibrolytic bacteria, which can contribute to the reduction of digestive disorders and metabolic diseases in animals that receive diets with high concentrate in pasture intensive termination systems.

Host and altitude factors affect rumen bacteria in cattle.

There are many kinds of microorganisms in the gastrointestinal tract of mammals, some of which are closely related to the host. Rumen microorganisms are essential for normal physiological activities of their host by decomposing plant crude lignin and providing essential nutrients. The composition and diversity of this microbial population are influenced by the host, environment, and diet. Despite its importance, little is known about the effects of factors such as altitude variation on rumen microbial population abundance and diversity in different ruminants. Here, we described the changes in overall rumen bacteria in four groups of cattle, including the Zhongdian yellow cattle and Zhongdian yaks, grazing at high altitudes (3600 m); the Jiangcheng yellow cattle and Jiangcheng buffalo were kept at an altitude of 1100 m. We found that there was a significant difference in rumen bacterial abundance of the Zhongdian yellow cattle and Zhongdian yaks at high altitude and there was obvious homogeneity in rumen bacterial abundance and diversity in the Jiangcheng yellow cattle and Jiangcheng buffalo at low altitude. Therefore, our research concluded that under the same dietary environment, there were differences in the abundance and diversity of certain bacteria in the rumen of different breeds of cattle, indicating that host genetic factors and intestinal microorganisms related to altitudinal variation had a greater influence on rumen bacterial abundance in the cattle.

Compositional and structural dynamics of the ruminal microbiota in dairy heifers and its relationship to methane production.

BACKGROUND: Heifers emit more enteric methane (CH4 ) than adult cows and these emissions tend to decrease per unit feed intake as they age. However, common mitigation strategies like expensive high-quality feeds are not economically feasible for these pre-production animals. Given its direct role in CH4 production, altering the rumen microbiota is another potential avenue for reducing CH4 production by ruminants. However, to identify effective microbial targets, a better understanding of the rumen microbiota and its relationship to CH4 production across heifer development is needed. RESULTS: Here, we investigate the relationship between rumen bacterial, archaeal, and fungal communities as well as CH4 emissions and a number of production traits in prepubertal (PP), pubertal (PB), and pregnant heifers (PG). Overall, PG heifers emitted the most CH4 , followed by PB and PP heifers. The bacterial genus Acetobacter and the archaeal genus Methanobrevibacter were positively associated, while Eubacterium and Methanosphaera were negatively associated with raw CH4 production by heifers. When corrected for dietary intake, both Eubacterium and Methanosphaera remained negatively associated with CH4 production. CONCLUSION: We suggest that Eubacterium and Methanosphaera represent likely targets for CH4 mitigation efforts in heifers as they were negatively associated with CH4 production and not significantly associated with production traits. © 2018 Society of Chemical Industry.

Isolation and fermentative activity of rumen anaerobic fungi in dairy cows / Isolamento e atividade fermentativa de fungos anaeróbios do rúmen de vacas leiteiras

The possibility of biotechnological application of anaerobic fungi and their biomass-degrading enzymes has been a growing area of research and development over the past decade. In this context, the occurrence and isolation of rumen fungi were evaluated in three Holstein-Gir dairy cows grazing Urochloa spp., in addition to the fermentation capacity of theses isolates in media containing different carbohydrates. Motile zoospores were found in all of the rumen samples. Twelve fungal strains were recovered and were capable of degrading different carbohydrates and lignocellulosic components, suggesting that these strains are able to produce various degradative enzymes when grown on glucose, xylose, cellobiose, fructose, and cellulose. Results pointed out the first insight into the isolation of rumen anaerobic fungi in dairy cattle in Brazil and suggested that further studies are needed to show the potential of some species for commercial application, especially in tropical ruminants.(AU)

A possibilidade de aplicação biotecnológica dos fungos anaeróbios, e suas enzimas de degradação de biomassa, tem sido uma área cada vez maior de pesquisa e desenvolvimento na última década. Neste contexto, a ocorrência e o isolamento de fungos ruminais foram avaliados em três vacas Holandês x Gir sob pastejo de Urochloa spp., além da capacidade de fermentação dos isolados em meios de cultura contendo diferentes fontes de carboidratos. Zoósporos móveis foram encontrados em todos os conteúdos ruminais analisadas. Doze isolados foram recuperados e todos foram capazes de degradar diferentes carboidratos e componentes lignocelulósicos, sugerindo que estes isolados são capazes de produzir várias enzimas degradativas. Estes resultados revelaram as primeiras descobertas sobre o isolamento de fungos anaeróbios ruminais em gado leiteiro no Brasil e sugere que estudos adicionais são necessários para evidenciar o potencial de algumas espécies para a aplicação comercial, principalmente em ruminantes tropicais.(AU)

Isolation and fermentative activity of rumen anaerobic fungi in dairy cows / Isolamento e atividade fermentativa de fungos anaeróbios do rúmen de vacas leiteiras

The possibility of biotechnological application of anaerobic fungi and their biomass-degrading enzymes has been a growing area of research and development over the past decade. In this context, the occurrence and isolation of rumen fungi were evaluated in three Holstein-Gir dairy cows grazing Urochloa spp., in addition to the fermentation capacity of theses isolates in media containing different carbohydrates. Motile zoospores were found in all of the rumen samples. Twelve fungal strains were recovered and were capable of degrading different carbohydrates and lignocellulosic components, suggesting that these strains are able to produce various degradative enzymes when grown on glucose, xylose, cellobiose, fructose, and cellulose. Results pointed out the first insight into the isolation of rumen anaerobic fungi in dairy cattle in Brazil and suggested that further studies are needed to show the potential of some species for commercial application, especially in tropical ruminants.

A possibilidade de aplicação biotecnológica dos fungos anaeróbios, e suas enzimas de degradação de biomassa, tem sido uma área cada vez maior de pesquisa e desenvolvimento na última década. Neste contexto, a ocorrência e o isolamento de fungos ruminais foram avaliados em três vacas Holandês x Gir sob pastejo de Urochloa spp., além da capacidade de fermentação dos isolados em meios de cultura contendo diferentes fontes de carboidratos. Zoósporos móveis foram encontrados em todos os conteúdos ruminais analisadas. Doze isolados foram recuperados e todos foram capazes de degradar diferentes carboidratos e componentes lignocelulósicos, sugerindo que estes isolados são capazes de produzir várias enzimas degradativas. Estes resultados revelaram as primeiras descobertas sobre o isolamento de fungos anaeróbios ruminais em gado leiteiro no Brasil e sugere que estudos adicionais são necessários para evidenciar o potencial de algumas espécies para a aplicação comercial, principalmente em ruminantes tropicais.

Differencial rumen protozoa counting from steers fed Napier elephant grass (Pennisetum purpureum Schum) at different maturity stages / Contagens diferenciais de protozoários ciliados em rúmen de bovinos arraçoados com capim elefante Napier (Pennisetum purpureum Schum), em vários estádios de crescimento vegetativo

Napier grass (Pennisetum purpureum Schum) in-3 growing stages: a) 1,30 m tall and 17.54% dry matter; b) 2.35 m tall and 25.84% dry matter: and c) 3,25 m tall and 26.31% dry matter, was fed "ad libitum" to eight rumen fistulated steers all crossbred (5/8 european-zebu) weighting 220 kg, being fed 1,5 kg of a concentrate meal with 24.16% of crude protein. Treatments were compared in a completely randonmized design using the 4th week of each experimental period for rumen liquor sampling for differencial counts of the following protozoa: Entodinium, Diplodinium, Eudipiodinium and Polyplastron. Results showed Entodinium as 96.73% of total protozoa and its concentration per mililiter of rumen fluid decreased linearly as the plant matured (a = 18.2 x 104/ml; b = 12.1 x 104/ml; and c = 9.8 x 104/ml).

Capim elefante Napier (Pennisetum purpureum Schum) colhido em quatro estádios de desenvolvimento: a) 1,30 m de altura e 17,54% de matéria seca; b) 2,35 m de altura e 25,84% de matéria seca; e c) 3,25 m de altura e 26,31% de matéria seca, foi fornecido ad libitum" a 8 bovinos com 5/8 de sangue europeu-zebu, com 220 kg de peso vivo médio, providos de fístulas ruminais. Todos receberam 1,5 kg de uma mistura concentrada com 24,10% de proteína bruta. Os tratamentos foram comparados em um delineamento inteiramente casualizado, sendo que na quarta semana de cada período experimental colheram-se amostras de líquido de rúmen antes da oferta dos alimentos, para contagens diferenciais dos seguintes gêneros de protozoários ciliados e auferir suas concentrações por mililitro: Entodinium spp; Diplodinium spp; Eudiplodinium spp e Polyptastron spp. Os resultados mostraram que os protozoários ciliados do gênero Entodinium predominaram com 96,73% do total da população desses microorganismos. O número de Entodinium spp decresceu com a maturação da planta: a) 18,2 x 104/ml; b) 12,1 x 104/ml; e c) 9,8 x 104/ml.

Rúmen ciliate protozoa in buffalo (Bubaíus bubalis L.) and zebu cattle (Bos indicus L.) kept in a feedlot / Avaliação dos protozoários ciliados no rúmen de búfalos (Bubalus bubalis L.) e bovinos (Bos indicus L.) em regime de confinamento

Nine castrated male buffaloes and nine Zebu steers aging 18 to 24 months and weighing 330 to 350kg in average, respectively, were individually fed: 2Kg unheated ground soybean; 2 kg crushed corn ears(grains, hulls and cobs) plus sorghum silage "ad libitum" with daily control of intake, during 112 days in a feedlot experiment. All animals were killed at the end of the experiment and the content of each rumen was homogenized and sampled 30 to 40 ml of ruminal fluid, from which a 10 ml aliquot was collected in a test tube containing 20 ml of a solution (formaldehyde 1:2 in distilled water) being immediately shaken for the fixation of the ciliate protozoa. After identification and counting of the protozoa the following conclusions were achieved: 1)There was a higher concentration of ciliate protozoa in Zebu than in buffalo despite the fact that more genera of protozoa were present in buffalo; 2) ciliate protozoa, digestors of fibre, were detected in higher number in Zebu cattle; 3) Entodinium spp represented more than 80% of total ciliate protozoa both in Zebu cattle and buffalo.

Num experimento de engorda em confinamento, foram utilizados nove bubalinos e nove zebuínos, todos machos castrados, de 18 a 24 meses de idade e peso médio de 340 kg, mantidos em baias individuais, consumindo dieta de 2,0 kg de soja crua moída, 2,0 kg de espigas de milho desintegradas (grão, palha e sabugo) e silagem de sorgo à vontade (controlando-se o consumo diário). Ao final do período de confinamento, todos os animais foram abatidos e o conteúdo ruminal de cada indivíduo foi homogeneizado, sendo colhidas amostras de 30 a 40 ml de liquido ruminal e, desta, retirou-se alíquota de 10 ml em tubo de ensaio com 20ml de formaldeído diluído em água destilada a 1:2,para fixação dos protozoários ciliados. As contagens de protozoários foram feitas em 100 campos e os resultados permitiram as seguintes conclusões: 1) adieta favoreceu maior concentração de protozoários ciliados/ml de liquido ruminal dos zebuínos que no de bubalinos, apesar destes apresentarem maior número de gêneros; 2) os protozoários ciliados digestores de fibra foram detectados em maior quantidade nos zebuínos que nos bubalinos; 3) o gênero Emodinium spp representou mais de 80% do total dos protozoários ciliados identificados nos zebuínos e nos bubalinos.

Effects of Leucaena leucocephala (Lam.) de Wit on concentration of ciliate protozoa in the rumen of sheep / Efeitos da Leucaena leucocephala (Lam.) de Wit sobre a concentração de protozoários ciliados no rúmen de ovinos

Two completely randomized trials with sheep we re run to study the feeding Leucaena leucocephala on concentration of rumen ciliate protozoa. In trial 1, ten sheep were subjected to two frequencies (twice or four times daily) being the Leucaena hay fed as sole diet. In trial 2, nine sheep were subjected to three treatments: a) 100% Rhodes grass hay (Chloris gayana kunth); b) 30:70%; c) 50 : 40% Leucaena hay and Rhodes grass hay, respectively. The animals were adapted for 21 day period, and after that, rumen fluid samples were taken from each sheep via stomach tube before first feeding. Increasing the feeding frequencies from 2 to 4 times/ day resulted in a decrease in total and ciffsrental numbe"rs of protozoa, excet for genus Epidinium spp. which was not present. The levels 30% and 60% of Leucaena hay in diet on dry matter bases did not result in a significant change in concentration of rumen ciliate protozoa, excet the genus Dasytrich a spp. which showed significant decrease (P 0,05). Differential protozoa counts revealed that Entodinia species  predominanted when sheep were fed only Leucaena (30.0%). From those rindings, it may be made an hypotesis of protozoocid" action of mimosine or DHP "per si" or products of mimosine metabolism, facilitated for feeding frequencies of microrganisms in the rumen with increase in number of bacteria species breacKdown these compounds d

Foram realizadas contagens totais e de cinco principais gêneros de protozoários ciliados do rúmen: Entodinium spp., Diplodinim spp., Epidinium spp., Dasytricha spp. e Isotricha spp., por mL de líquido ruminal em carneiros submetidos a dois experimentos inteiramente casualizados. No Exp. 1, cinco animais receberam apenas feno de leucena [( Leucaena leucocephala (Lam.) de Wit)] duas vezes ao dia (7:00 e 18:00 horas) e cinco foram alimentados quatro vezes ao dia (7:00; 13:00; 18:00 e 01:00 horas). No Exp. 2, nove destes animais foram sorteados em três tratamentos, com três repetições por tratamento, sendo: a) somente feno de capim de Rhodes (Chloris gayana kunth); b) 30 : 70 % e c) 60 : 40 % de feno de leucena mais feno de Rhodes, respectivamente. O aumento na freqüência de alimentação de duas para quatro vezes ao dia reduziu significativamente o número dos ciliados estudados, exceto para o gênero Epidinium spp., que não foi encontrado em nenhum animal. A substituição parcial do feno de capim de Rhodes pelo feno de leucena nos dois níveis 30 e 80% da M.S. não produziu diferenças significativas nas contagens total e diferencial dos protozoários, exceto para o gênero Dasytricha spp. que mostrou diminuição significativa CP ( 0,05). Houve predominância do gênero Entodinium spp., (cerca de 90,0%) quando os animais receberam exclusivamente feno de leucena. Estes dados permitem levantar

Effects of Leucaena leucocephala (Lam.) de Wit on concentration of ciliate protozoa in the rumen of sheep / Efeitos da Leucaena leucocephala (Lam.) de Wit sobre a concentração de protozoários ciliados no rúmen de ovinos

Two completely randomized trials with sheep we re run to study the feeding Leucaena leucocephala on concentration of rumen ciliate protozoa. In trial 1, ten sheep were subjected to two frequencies (twice or four times daily) being the Leucaena hay fed as sole diet. In trial 2, nine sheep were subjected to three treatments: a) 100% Rhodes grass hay (Chloris gayana kunth); b) 30:70%; c) 50 : 40% Leucaena hay and Rhodes grass hay, respectively. The animals were adapted for 21 day period, and after that, rumen fluid samples were taken from each sheep via stomach tube before first feeding. Increasing the feeding frequencies from 2 to 4 times/ day resulted in a decrease in total and ciffsrental numbe"rs of protozoa, excet for genus Epidinium spp. which was not present. The levels 30% and 60% of Leucaena hay in diet on dry matter bases did not result in a significant change in concentration of rumen ciliate protozoa, excet the genus Dasytrich a spp. which showed significant decrease (P 0,05). Differential protozoa counts revealed that Entodinia species  predominanted when sheep were fed only Leucaena (30.0%). From those rindings, it may be made an hypotesis of protozoocid" action of mimosine or DHP "per si" or products of mimosine metabolism, facilitated for feeding frequencies of microrganisms in the rumen with increase in number of bacteria species breacKdown these compounds d

Foram realizadas contagens totais e de cinco principais gêneros de protozoários ciliados do rúmen: Entodinium spp., Diplodinim spp., Epidinium spp., Dasytricha spp. e Isotricha spp., por mL de líquido ruminal em carneiros submetidos a dois experimentos inteiramente casualizados. No Exp. 1, cinco animais receberam apenas feno de leucena [( Leucaena leucocephala (Lam.) de Wit)] duas vezes ao dia (7:00 e 18:00 horas) e cinco foram alimentados quatro vezes ao dia (7:00; 13:00; 18:00 e 01:00 horas). No Exp. 2, nove destes animais foram sorteados em três tratamentos, com três repetições por tratamento, sendo: a) somente feno de capim de Rhodes (Chloris gayana kunth); b) 30 : 70 % e c) 60 : 40 % de feno de leucena mais feno de Rhodes, respectivamente. O aumento na freqüência de alimentação de duas para quatro vezes ao dia reduziu significativamente o número dos ciliados estudados, exceto para o gênero Epidinium spp., que não foi encontrado em nenhum animal. A substituição parcial do feno de capim de Rhodes pelo feno de leucena nos dois níveis 30 e 80% da M.S. não produziu diferenças significativas nas contagens total e diferencial dos protozoários, exceto para o gênero Dasytricha spp. que mostrou diminuição significativa CP ( 0,05). Houve predominância do gênero Entodinium spp., (cerca de 90,0%) quando os animais receberam exclusivamente feno de leucena. Estes dados permitem levantar

Chronological establishment of ciliate protozoa in rumen of Mantiqueira calves (Bos taurus L.) from Paraiba Valley, SP / Cronologia do aparecimento de protozoários ciliados no rúmen de bezerros do tipo Mantiqueira (Bos taurus L.) na região do Vale do Rio Paraíba, SP

Five protozoa species (Entodinium sp, Diplodinium sp, Epidinium sp, Isotricha sp and Dasytricha sp) were counted per mililiter of rumen content in 115 Mantiqueira calves aged from 7 to 270 days. Entodinium sp was the first protozoan to establish itself, when the calves were 2 months old and the rumen pH was 4.22 ± 0.12, followed by Diplodinium sp and Epidinium sp that were established between 91 and 120 days old, in calves, with rumen pH of 5.75 ± 0.26. Isotricha sp was detected in caives from 121 to 150 days old, when pH was 5.98 ± 0.12. Dasytricha sp was counted in calves aged from 184 to 270 days with rumen pH of 6.75 ±0.06. It seems that in Mantiqueira calves ruminal protozoa are found earlier than in Holstein calves, although the development of these protozoa was slower than it has been known for Holstein calves.

Realizando contagens de protozoários, por ml de suco ruminal, efetuadas em 115 bezerros do tipo Mantiqueira, com idade variando de 7 a 270 dias, pôde ser verificada a presença de espécies de cinco gêneros: Entodinium, Diplodinium, Epidinium, Isotricha e Dasytricha. Na sequência cronologia, o primeiro gênero identificado foi Entodinium, já no segundo mês de vida do hospedeiro, embora o pH do rúmen fosse 4,22 ± 0,12. As espécies de Diplodinium e Epidinium surgiram entre 91 e 120 dias, quando o pH do rúmen alcançou 5,75 ± 0,26. O gênero Isotricha apareceu na faixa etária de 121 a 150 dias, quando o pH atingiu a 5,98 ± 0,12; espécies de Dasytricha foram encontradas entre 184 a 270 dias, quando o pH do rúmen exibiu valores de 6,75 ±0,06. Cotejando estes resultados com os referidos na literatura, é possível concluir que, em bezerros do tipo Mantiqueira, é ligeiramente mais precoce o aparecimento de protozoários. De outro lado, é menos acelerado o desenvolvimento desses protozoários, com relação ao que se observa em bezerros da raça Holandesa.

Chronological establishment of ciliate protozoa in rumen of Mantiqueira calves (Bos taurus L.) from Paraiba Valley, SP / Cronologia do aparecimento de protozoários ciliados no rúmen de bezerros do tipo Mantiqueira (Bos taurus L.) na região do Vale do Rio Paraíba, SP

Five protozoa species (Entodinium sp, Diplodinium sp, Epidinium sp, Isotricha sp and Dasytricha sp) were counted per mililiter of rumen content in 115 Mantiqueira calves aged from 7 to 270 days. Entodinium sp was the first protozoan to establish itself, when the calves were 2 months old and the rumen pH was 4.22 ± 0.12, followed by Diplodinium sp and Epidinium sp that were established between 91 and 120 days old, in calves, with rumen pH of 5.75 ± 0.26. Isotricha sp was detected in caives from 121 to 150 days old, when pH was 5.98 ± 0.12. Dasytricha sp was counted in calves aged from 184 to 270 days with rumen pH of 6.75 ±0.06. It seems that in Mantiqueira calves ruminal protozoa are found earlier than in Holstein calves, although the development of these protozoa was slower than it has been known for Holstein calves.

Realizando contagens de protozoários, por ml de suco ruminal, efetuadas em 115 bezerros do tipo Mantiqueira, com idade variando de 7 a 270 dias, pôde ser verificada a presença de espécies de cinco gêneros: Entodinium, Diplodinium, Epidinium, Isotricha e Dasytricha. Na sequência cronologia, o primeiro gênero identificado foi Entodinium, já no segundo mês de vida do hospedeiro, embora o pH do rúmen fosse 4,22 ± 0,12. As espécies de Diplodinium e Epidinium surgiram entre 91 e 120 dias, quando o pH do rúmen alcançou 5,75 ± 0,26. O gênero Isotricha apareceu na faixa etária de 121 a 150 dias, quando o pH atingiu a 5,98 ± 0,12; espécies de Dasytricha foram encontradas entre 184 a 270 dias, quando o pH do rúmen exibiu valores de 6,75 ±0,06. Cotejando estes resultados com os referidos na literatura, é possível concluir que, em bezerros do tipo Mantiqueira, é ligeiramente mais precoce o aparecimento de protozoários. De outro lado, é menos acelerado o desenvolvimento desses protozoários, com relação ao que se observa em bezerros da raça Holandesa.

Rumen"s microbial population of dairy cows under different rations / Populações microbianas dos rúmens de vacas leiteiras submetidas a diversas rações

Three fistulated Holstein cows were used in "change-over" design comparing three different treatments made with orchad grass pasture plus: A) no/concentrate mixture; B) 3,0 kg/concentrate mixture/cow/day; C) 6,0 kg/concentrate mixture/cow/day. Two separated collections of rumen contents were made in each subperiod of 28 days, to collect the following data, for treatments A, B, or C: liquid rumen volume: turn-overs by 24 hours; total bacterial counts/ml of rumen content; amilolytic bacterial counts/ml of rumen content; total numbers of rumen bacteria; dry matter of rumen content; pH values; and results concerning protozoa, on a relative percentual basis, for: Entodinium sp; Diplodinium sp and Dasytricha sp. For all data there were no statistical differences among the treatments.

Três vacas Holandesas fistuladas, foram utilizadas para comparar, dentro de um delineamento em "change-over, três tratamentos com pastos de "orchad grass" (Dactylis glomerata L.),com as seguintes quantidades de concentrados por vaca e por dia: A) zero kg; B) 3,0 kg e C) 6,0 kg. Os períodos de experimentação foram de 28 dias cada um. Na última semana realizaram-se duas coletas independentes dos conteúdos ruminais. Registraram-se os volumes ruminais, em litros; as reciclagens ("turnover") por 24 horas; os números totais de bactérias por ml de conteúdo ruminal; os números de bactérias amilolíticas por ml de conteúdo ruminal; os números totais de bactérias no rúmen; os valores de matéria seca dos conteúdos ruminais; os valores de pH e as porcentagens relativas dos protozoários dos géneros Entodimium sp, Diplodimium sp e Dasytricha sp. Não foram observadas diferenças significativas entre tratamentos, para todas as medidas citadas.

Antibiotics in calf starters: differences in rumen microbial populations / Antibióticos em rações de bezerros: alterações nas populações microbianas dos rúmens

Nineteen Holstein calves were used in a randonmized design, distributed on a 2x2 fatorial treatment, being fed: with (treatment A) and without (treatment B) antibiotics up to 8 weeks old. In the 4th and 7th week, ruminal samples were collected through aesophageal tube. Rumen volumes were estimated through the Polyethylenglicol (PEG) technique. Results showed an increase in rumen volumes from 4 to 7 weeks, this increment was similar for both treatments. There were no statistical differences between animals concerning bacterial counts/ml rumen liquor.

Dezenove bezerros foram utilizados em um delineamento inteiramente casualizado, num esquema fatorial 2x2, recebendo orações com antibióticos (tratamento A) e sem antibióticos (tratamento B), do nascimento até a 8ª semana de idade. Durante a 4ª e 7ª semanas de vida, os animais tiveram seus conteúdos ruminais amostrados por sonda esofagiana. Os volumes dos rúmens foram medidos com uso de polietilenoglicol (PEG) como marcador. Os resultados mostraram que, para ambos os tratamentos, os volumes ruminais aumentaram da 4ª para a 7ª semana de idade. No tocante ao número de bactérias presentes por ml de líquido ruminal, não ocorreram diferenças estatisticamente significativas entre os tratamentos.

Antibiotics in calf starters: differences in rumen microbial populations / Antibióticos em rações de bezerros: alterações nas populações microbianas dos rúmens

Nineteen Holstein calves were used in a randonmized design, distributed on a 2x2 fatorial treatment, being fed: with (treatment A) and without (treatment B) antibiotics up to 8 weeks old. In the 4th and 7th week, ruminal samples were collected through aesophageal tube. Rumen volumes were estimated through the Polyethylenglicol (PEG) technique. Results showed an increase in rumen volumes from 4 to 7 weeks, this increment was similar for both treatments. There were no statistical differences between animals concerning bacterial counts/ml rumen liquor.

Dezenove bezerros foram utilizados em um delineamento inteiramente casualizado, num esquema fatorial 2x2, recebendo orações com antibióticos (tratamento A) e sem antibióticos (tratamento B), do nascimento até a 8ª semana de idade. Durante a 4ª e 7ª semanas de vida, os animais tiveram seus conteúdos ruminais amostrados por sonda esofagiana. Os volumes dos rúmens foram medidos com uso de polietilenoglicol (PEG) como marcador. Os resultados mostraram que, para ambos os tratamentos, os volumes ruminais aumentaram da 4ª para a 7ª semana de idade. No tocante ao número de bactérias presentes por ml de líquido ruminal, não ocorreram diferenças estatisticamente significativas entre os tratamentos.

Rumen"s microbial population of dairy cows under different rations / Populações microbianas dos rúmens de vacas leiteiras submetidas a diversas rações

Three fistulated Holstein cows were used in "change-over" design comparing three different treatments made with orchad grass pasture plus: A) no/concentrate mixture; B) 3,0 kg/concentrate mixture/cow/day; C) 6,0 kg/concentrate mixture/cow/day. Two separated collections of rumen contents were made in each subperiod of 28 days, to collect the following data, for treatments A, B, or C: liquid rumen volume: turn-overs by 24 hours; total bacterial counts/ml of rumen content; amilolytic bacterial counts/ml of rumen content; total numbers of rumen bacteria; dry matter of rumen content; pH values; and results concerning protozoa, on a relative percentual basis, for: Entodinium sp; Diplodinium sp and Dasytricha sp. For all data there were no statistical differences among the treatments.

Três vacas Holandesas fistuladas, foram utilizadas para comparar, dentro de um delineamento em "change-over, três tratamentos com pastos de "orchad grass" (Dactylis glomerata L.),com as seguintes quantidades de concentrados por vaca e por dia: A) zero kg; B) 3,0 kg e C) 6,0 kg. Os períodos de experimentação foram de 28 dias cada um. Na última semana realizaram-se duas coletas independentes dos conteúdos ruminais. Registraram-se os volumes ruminais, em litros; as reciclagens ("turnover") por 24 horas; os números totais de bactérias por ml de conteúdo ruminal; os números de bactérias amilolíticas por ml de conteúdo ruminal; os números totais de bactérias no rúmen; os valores de matéria seca dos conteúdos ruminais; os valores de pH e as porcentagens relativas dos protozoários dos géneros Entodimium sp, Diplodimium sp e Dasytricha sp. Não foram observadas diferenças significativas entre tratamentos, para todas as medidas citadas.