Plant extracts have been proposed as substitutes for chemical feed additives due to their potential as rumen fermentation modifiers and because of their antimicrobial and antioxidant activities, possibly reducing methane emissions. This study aimed to evaluate the use of oregano (OR), green tea extracts (GT), and their association as feed additives on the performance and methane emissions from dairy between 28 and 87 d of lactation. Thirty-two lactating dairy cows, blocked into 2 genetic groups: 16 Holstein cows and 16 crossbred Holstein-Gir, with 522.6 ± 58.3 kg of body weight, 57.2 ± 20.9 d in lactation, producing 27.5 ± 5.0 kg/cow of milk and with 3.1 ± 1.8 lactations were evaluated (means ± standard error of the means). Cows were allocated into 4 treatments: control (CON), without plant extracts in the diet; oregano extract (OR), with the addition of 0.056% of oregano extract in the dry matter (DM) of the diet; green tea (GT), with the addition of 0.028% of green tea extract in the DM of the diet; and mixture, with the addition of 0.056% oregano extract and 0.028% green tea extract in the DM of the diet. The forage-to-concentrate ratio was 60:40. Forage was composed of corn silage (94%) and Tifton hay (6%); concentrate was based on ground corn and soybean meal. Plant extracts were supplied as powder, which was previously added and homogenized into 1 kg of concentrate in natural matter, top-dressed onto the total mixed diet. No treatment by day interaction was observed for any of the evaluated variables, but some block by treatment interactions were significant. In Holstein cows, the mixture treatment decreased gross energy and tended to decrease the total-tract apparent digestibility coefficient for crude protein and total digestible nutrients when compared with OR. During the gas measurement period, GT and OR increased the digestible fraction of the ingested DM and decreased CH expressed in grams per kilogram of digestible DMI compared with CON. The use of extracts did not change rumen pH, total volatile fatty acid concentration, milk yield, or most milk traits. Compared with CON, oregano addition decreased fat concentration in milk. The use of plant extracts altered some milk fatty acids but did not change milk fatty acids grouped according to chain length (short or long), saturation (unsaturated or saturated), total conjugated linoleic acids, and n-3 and n-6 contents. Green tea and oregano fed separately reduced gas emission in cows during the first third of lactation and have potential to be used as feed additives for dairy cows.
-The objective of this research was to determine the variation of milk stability evaluated with ethanol, boiling, and coagulation time tests (CTT) to identify milk components related with stability and verify the correlation between the three methods. Bulk raw milk was collected monthly at 50 dairy farms from January 2007 to October 2009 and physicochemical attributes, somatic cell (SCC), and total bacterial counts (TBC) were determined. Milk samples were classified into low, medium, and high stability to ethanol test when coagulation occurred at 72 °GL, between 74 and 78 °GL, and above 78 °GL, respectively. Univariate analysis was performed considering the effects of year, months, and interaction in a completely randomized design. Principal factor analysis and logistic regression were done. There was an interaction between months and years for stability to the ethanol test and coagulation time. All samples were stable at the boiling test. Boiling test was not related to ethanol and coagulation time tests. Coagulation time was weakly but positively correlated with ethanol test. Broken line analysis revealed that milk stability measured with CTT and ethanol tests decreased sharply when SCC attained 790,000 or 106 cell/mL of milk, respectively. Milk stability measured with ethanol test decreased when TBC was higher than 250,000 cfu/mL, while there was no inflexion point between TBC and stability measured with CTT. Milk with high stability presented lower values for acidity, TBC, and SCC but higher values for pH, lactose, protein, and CTT compared with lowstability milk. Due to the execution easiness, single-point cut-off result and low cost, we do not recommend the replacement of ethanol test for boiling or coagulation time test.Key Words: milk composition, seasonality, somatic cell count Revista Brasileira de Zootecnia
ABSTRACT. The experiment aimed at evaluating leaf biomass flow, intensity and frequency of defoliation of Alexandergrass (Urochloa plantaginea (Link) Hitch) by beef heifers exclusively on pasture or that grazed and received protein salt. A completely randomized experimental design was used with repeated measures over time, two treatments and two area replications, with three Angus test heifers by paddock. Leaf blade intake flow is 18% superior for heifers exclusively on pasture. Grazing intensity (59.8%) is similar when heifers receive protein salt or not. Heifers receiving protein salt reduce by one day the defoliation frequency of tillers. The supply of protein salt for beef heifers grazing Alexandergrass affects the herbivore-plant relationship, decreasing intake flow and leaf blade defoliation frequency.Keywords: defoliation frequency, defoliation intensity, morphogenesis, Urochloa plantaginea.Fluxos de biomassa e padrões de desfolhação em papuã pastejado por bezerras recebendo ou não sal proteinado RESUMO. O experimento foi conduzido para avaliar os fluxos de biomassa foliar, intensidade e frequência de desfolhação em papuã (Urochloa plantaginea (Link) Hitch), pastejado por bezerras de corte exclusivamente em pastejo ou em pastejo e recebendo sal proteinado. O delineamento foi inteiramente casualizado, com medidas repetidas no tempo, dois tratamentos e duas repetições de área, com três bezerras testes da raça Angus por piquete. O fluxo de consumo de lâminas foliares é 18% superior quando as bezerras permanecem exclusivamente em pastejo. A intensidade de pastejo (59,8%) é semelhante quando as bezerras recebem sal proteinado ou não. Bezerras que recebem suplemento reduzem em um dia a frequência de desfolhação dos perfilhos. O fornecimento de sal proteinado para bezerras de corte em pastejo em papuã resulta em alterações na relação herbívoro-planta reduzindo o fluxo de consumo e a frequência de desfolhação de lâminas foliares.Palavras-chave: frequência de desfolhação, intensidade de desfolhação, morfogênese, Urochloa plantagine.
RESUMOO consumo de forragem fo i avaliado em novilhas de corte exclusivamente em pastagem de azevém (Lolium multijlorum Lam.) ou recebendo farelo de arroz integral (FAI) com ou sem adição de ionóforo. Foi usado o óxido de cromo como indicador da produção fecal. O delineamento experimental fo i o inteiramente casualizado, com medidas repetidas no tempo, com três tratamentos e três repetições de área. Os animais foram considerados as unidades experimentais nas avaliações de consumo. O consumo de pasto pelas novilhas fo i similar nos diferentes sistemas alimentares, ocasionando taxa de lotação semelhante. O fornecimento de farelo de arroz integral, com ou sem monensina, aumenta o consumo de matéria seca total. A adição de ionóforo ao FAI aumenta o desempenho individual das novilhas, sendo o seu uso recomendado quando existe o objetivo de reduzir a sua idade ao primeiro acasalamento. Palavras-chave: Angus, Lolium multiflorum Lam., monensina, óxido de cromo. ABSTRACTThe forage intake was evaluated in beef heifers exclusively in Italian ryegrass (Lolium multiflorum Lam.) pasture or receiving rice bran with or without addition o f ionophore. Chromic oxide was used as a fecal production indicator. The experimental design was completely randomized with repeated measures on time, three treatments and three area replicates. The animals were considered experimental units fo r intake evaluations. The pasture intake by heifers was similar at different feeding systems causing similar stocking rate. The supply o f rice bran with or without monensin increased the total dry matter intake. The individual heifers performance was increased with ionophore addition to rice bran. Ionophore is recommended when there is a goal to reduce the age o f beef heifers at their first mating. INTRODUÇÃOO consumo voluntário de forragem é o principal fator que influencia a produtividade dos sistemas em pastejo, sendo influenciado por características relacionadas ao animal, à planta, ao suplemento fornecido, ao ambiente e ao manejo imposto ao pasto. O consumo total de matéria seca é menor em ruminantes mantidos exclusivamente em pastejo, em relação aos que recebem suplementos, e é esperado melhor desempenho de bovinos de alta produção quando há inclusão de suplementos em sua dieta, permitindo que esses expressem seu potencial genético. ROSA et al. (2013), no entanto, não observaram mudança na ingestão total de matéria seca, independente do estádio de desenvolvimento do pasto, quando novilhas receberam grão de milho ou gordura extrusada em pastagem de azevém (Lolium multiflorum Lam.).Dentre os suplementos que podem ser utilizados para animais em pastejo em azevém, destaca-se o farelo de arroz integral (FAI), por sua abundância regional. No Rio Grande do Sul, na safra 2011/12, estima-se que tenham sido produzidas aproximadamente 680 mil toneladas desse subproduto. Respostas anteriores, obtidas com o uso do FAI na recria de novilhas de corte, em pastagem de inverno, mostram que, quando associado à polpa cítrica (1:1), proporcionou incrementos de 21,92% ...
Foi avaliado o efeito de diferentes frequências de suplementação sobre o uso da pastagem (fluxo de tecido foliar, intensidade e frequência de desfolhação) em papuã (Urochloa plantaginea (Link) Hitch). As bezerras de corte permaneceram exclusivamente em pastejo ou receberam grão inteiro de aveia durante sete ou cinco dias por semana (de segunda à sexta feira). A quantidade semanal de suplemento foi similar nas duas frequências. O delineamento experimental foi inteiramente casualizado, com medidas repetidas no tempo, três tratamentos e duas repetições de área. Os fluxos de tecidos, a frequência e intensidade de desfolhação são similares quando as bezerras permanecem exclusivamente em pastejo ou recebem grão de aveia em diferentes frequências.
ABSTRACT. The ingestive behavior of hoggets was assessed under intermittent grazing method with three days of paddock occupation. These animals remained exclusively on Italian ryegrass (Lolium multiflorum Lam) pasture or on ryegrass pasture and receiving 1.2% of DM in relation to body weight of rice paddy, corn grain or whole rice bran as a supplement during the vegetative, pre-flowering and flowering phenological stages of ryegrass. The experimental design was a randomized split-split plots wherein the types of supplement were considered as main plot, phenological stages as subplot and the days of occupation as sub-subplots. The hoggets grazed for a longer time when kept exclusively on ryegrass pasture. The hoggets grazed for less time in the vegetative stage of ryegrass and on the third day of paddock occupation. Feeding behavior of hoggets is changed when supplementation is provided in different phenological stages of the grass and days of paddock occupation.Keywords: rice bran, rice grain, corn grain, bite rate, grazing time.Comportamento ingestivo de borregas recebendo diferentes tipos de suplemento em pastagem de azevém RESUMO. Em método intermitente de pastejo, com três dias de ocupação dos piquetes, foi avaliado o comportamento ingestivo de borregas. Esses animais permaneceram em pastagem exclusiva de azevém (Lolium multiflorum Lam.) ou em pastagem de azevém recebendo 1,2% de MS em relação ao peso corporal de grão de arroz em casca, grão de milho moído ou farelo de arroz integral como suplemento durante os estádios fenológicos vegetativo, pré-florescimento e florescimento do azevém. O delineamento experimental foi o inteiramente casualizado em parcelas sub-subdivididas, sendo considerados os tipos de suplemento como parcelas principais, os estádios fenológicos como subparcelas e os dias de ocupação como sub-subparcelas. As borregas pastejaram por maior tempo quando permaneceram exclusivamente em azevém. As borregas pastejaram por menor tempo no estádio vegetativo do azevém e no terceiro dia de ocupação dos piquetes. O comportamento ingestivo de borregas é alterado quando é fornecido suplemento nos diferentes estádios fenológicos do pasto e nos dias de ocupação dos piquetes.Palavras-chave: farelo de arroz, grão de arroz, grão de milho, taxa de bocados, tempo de pastejo.
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