Large Particle Breakdown by Cattle Eating Ryegrass and Alfalfa

McLeod, M. N.; Minson, D. J.

doi:10.2527/jas1988.664992x

Cited by 108 publications

(75 citation statements)

References 17 publications

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“…Higher cell wall content has been traditionally correlated with lower intake [19] because this chemical attribute is linked to higher ruminal retention time [12]. In our study sample, the presence of two individual species (common vetch and oat) with different physical and chemical attributes makes it difficult to discriminate any single forage attribute that may influence intake.…”

Section: Discussionmentioning

confidence: 66%

Nutritive value of on-farm vetch-oat hays. I. Voluntary intake and nutrient digestibility

Haj-Ayed¹,

Gonzàlez²,

Caballero³

et al. 2000

Ann. Zootech.

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-Forage hay from the common vetch-oat intercrop has the potential to meet the forage deficit and integrate crop and livestock production in Mediterranean cereal-sheep systems. Groups of three wethers (1-2 year-old) were randomly allocated to individual on-farm hays of a sample size of 12 with the aim of assessing variability of botanical and chemical fractions, digestibility of nutrients, and DM intake. Vetch content (g . kg -1 DM) of hays (mean value = 557) ranged from 125 to 917. Mean contents (g . kg -1 DM) of crude protein (CP), neutral detergent fibre (NDF) and acid detergent lignin (ADL) were 126, 486, and 45 respectively. Variations of chemical composition between hays, and especially those of CP and ADL were partially explained by vetch proportion. Voluntary intake (g DM . kg -1 . BW 0.75 ) had a mean value of 64.2 and ranged from 49.0 to 78.9. Organic matter digestibility (mean value = 68.8%) ranged from 59.9 to 72.6%. The digestibility coefficient of nutrients and voluntary intake showed lower variability than that of chemical fractions, which, in turn, had a lower variability than that of botanical composition. The mean digestible energy (DE) concentration of the study sample was 11.72 MJ DE . kg -1 DM. Low variability of this value (CV = 5.9%) indicated a compensatory effect between vetch and oat. Vetch proportion in hay gave a better explanation of the variation of CP intake (r 2 = 0.63) than of the variation of DE intake (r 2 = 0.37). On-farm hays with at least 50% of vetch contribution may be considered as a production objective. This criterion may contribute to standardisation and marketing operations at the farm level.

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Section: Discussionmentioning

confidence: 66%

Nutritive value of on-farm vetch-oat hays. I. Voluntary intake and nutrient digestibility

Haj-Ayed¹,

Gonzàlez²,

Caballero³

et al. 2000

Ann. Zootech.

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“…Cows fed indoors had more ingestion and rumination sequences that were shorter and more evenly distributed throughout the day and night. Rumination plays an important role in the comminution of particle (Ulyatt et al, 1986;McLeod and Minson, 1988) and, the rate of particle comminution within the reticulorumen is an important determinant of particle passage rate from the reticulo-rumen (Ulyatt et al, 1986). Ingestion likely increases the outflow of particles from the rumen, compared to resting or ruminating, by increasing the frequency of reticulo-omasal orifice contractions (Okine et al, 1998).…”

Section: --mentioning

confidence: 99%

Effect of rumen fill on intake of fresh perennial ryegrass in young and mature dairy cows grazing or zero-grazing fresh perennial ryegrass

Boudon

Peyraud

Faverdin

et al. 2009

Animal

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Rumen fill may be a strong intake constraint for dairy cows fed on pasture, even though pasture is highly digestible in the grasslands of temperate climates. This constraint may also depend on the cows' maturity. Moreover, indoor feeding of fresh herbage may not always be a good model for the study of intake regulation at grazing. To test these hypotheses, four mature (6.3 6 0.72 year old) and four young (3.8 6 0.20 year old) dairy cows were offered fresh perennial ryegrass indoors or at grazing. The impact of rumen fill on intake was evaluated by addition of rumen inert bulk (RIB; coconut fiber, 15 l) compared to a control. The experimental design was a double 4 3 4 Latin square with four 14-day periods and a 2 3 2 factorial arrangement of two feeding methods (indoor feeding v. grazing), combined with the addition, or not, of RIB (RIB v. control), repeated for four mature and four young cows. Digestibility of offered herbage was 0.81. The average ytterbium measured dry matter intake (Yb DMI) was 19.0 and 15.5 kg/day for mature and young cows respectively ( P 5 0.019). The effect of RIB on predicted Yb DMI interacted with feeding method and cow age ( P 5 0.043). The presence of RIB decreased Yb DMI by 4.4 kg/day in mature cows at grazing and by 3.4 kg/day in young cows indoors, whereas it did not affect the Yb DMI of mature cows indoors or grazing young cows. Both grazing and young age constituted a clear constraint on the feeding behavior of the cows. Grazing cows had fewer ingestion and rumination sequences, which were longer and less evenly distributed throughout the day and night. Young cows had lower intake rates that were less adaptable to the feeding method and the presence of RIB. Mature cows clearly decreased their daily intake rate at grazing compared to indoor feeding, and with RIB compared to control, whereas the intake rate of young cows did not vary. These results indicate that rumen fill can represent a constraint on intake in grazing cows, even when highly digestible perennial ryegrass is offered. The study also shows that the impact of RIB on intake is highly dependent upon other constraints applied to the chewing behavior, which in this experiment were methods of offering herbage and cow age.Keywords: rumen fill, dairy cows, grazing, zero-grazing, ingestion ImplicationsLow and variable intake of fresh herbage is a strong constraint of milk production in grazing high genetic merit dairy cows in temperate climates. This paper aimed to test the hypothesis that rumen fill could be a determinant of intake in dairy cows offered pasture, even with highly digestible pasture. These results should contribute to a better understanding of the constraints involved in the low intake of grazing dairy cows, which will help to improve the prediction of daily intake variation and build new criteria for assessing sward quality. IntroductionIn temperate grazing systems, low and variable intake of fresh herbage has been reported as a strong constraint of milk production in grazing high genetic merit dairy cows. Gra...

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“…Diferenças entre Bos taurus e Bos indicus na eficiência de mastigação e comportamento deveriam também ser avaliadas para produção de ruminantes em condições tropicais. McLeod & Minson (1988) determinaram que mastigação e ruminação são as atividades mais importantes para reduzir o tamanho de partículas. No entanto, elas não respondem pela quebra total de partículas grandes (PG) e sugeriram que 17 % de redução de PG podem ser atribuídos à quebra por digestão microbiana e fricção no rúmen.…”

Section: (Recebido Para Publicação Em 6 De Abril De 2004 E Aprovado Eunclassified

Modelagem da redução do tamanho de partículas na alimentação de ruminantes

Saenz

2005

Ciênc. agrotec.

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RESUMOO tamanho de partícula influencia o valor nutricional do alimento porque pode afetar o consumo de matéria seca, a digestão e utilização de nutrientes pelos microorganismos ruminais e, o desempenho animal. Alguns modelos são apresentados para ilustrar a evolução da representação da redução do tamanho de partícula. Em geral, as diferentes propostas se comportam adequadamente e provêem informação útil para produção ou pesquisa. Porém, todos os modelos demonstram inexatidão em certos pontos. Nesta revisão são discutidas as razões para esses problemas e é proposta a inclusão de novas variáveis relacionadas com a cinética de partículas, ingestão descontínua de alimentos e liberação do conteúdo celular com o objetivo de aumentar a precisão de futuros modelos de consumo e digestão. Termos para indexação: cinética ruminal, consumo, digestibilidade, modelos de simulação. ABSTRACTParticle size seems to be an important factor influencing the nutritional value of the feed because it may affect dry matter intake, microbial digestion and utilization of nutrients and animal performance. Some models are described to present different attempts to represent particle size reduction. In general, the diverse approaches behave adequately and provide useful information for production or research. All models, however, demonstrate inaccuracy in some points. The reasons for these failures are discussed and the inclusion of new variables related to particle kinetics, pulses of feed and cell content release to increase accuracy of predictions in future models of feed intake and digestion of ruminants is proposed. Index terms: digestibility, feed intake, ruminal kinetics, simulation models. As forragens representam uma fração importante do consumo de energia em sistemas de produção de ruminantes. Existem muitos fatores que influenciam o consumo voluntário de alimentos (CVA) pelos ruminantes. A restrição física do CVA devido a atributos físicos das forragens é um dos mais importantes. Entre esses atributos, o tamanho de partícula pode ser um fator importante que influencia o valor nutricional do alimento porque afeta tanto o consumo de matéria seca (CMS) como a taxa na qual os nutrientes ficam disponíveis para digestão e utilização microbiana. Dependendo da qualidade da forragem, a redução de tamanho de partícula pela moagem ou peletização pode incrementar o consumo de forragens e alimentos fibrosos substancialmente (SOEST, 1994).O tamanho de partícula também afeta a taxa de passagem da ingesta através do rúmen. Quando o conteúdo ruminal chega a um ponto onde incremento adicional não é possível, a taxa de passagem da ingesta determina o consumo de alimento (BOSCH, 1991). A taxa na qual o alimento é reduzido a partículas suficientemente pequenas para atravessar o orifício retículo-omasal, e a taxa de degradação pelos microorganismos, são os fatores mais importantes que limitam o desaparecimento de digesta do rúmen.Por outro lado, embora uma fração das partículas ruminais possuam tamanho adequado para atravessar o orifício retículo-omasal...

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Large Particle Breakdown by Cattle Eating Ryegrass and Alfalfa

Cited by 108 publications

References 17 publications

Nutritive value of on-farm vetch-oat hays. I. Voluntary intake and nutrient digestibility

Nutritive value of on-farm vetch-oat hays. I. Voluntary intake and nutrient digestibility

Effect of rumen fill on intake of fresh perennial ryegrass in young and mature dairy cows grazing or zero-grazing fresh perennial ryegrass

Modelagem da redução do tamanho de partículas na alimentação de ruminantes

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