Sward composition, animal performance and the potential production of grass/white clover swards continuously stocked with sheep

Orr, R. J.; Parsons, A. J.; Penning, P. D.; Treacher, T. T.

doi:10.1111/j.1365-2494.1990.tb01957.x

Cited by 89 publications

(89 citation statements)

References 17 publications

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“…Pesquisadores (Orr et al, 1990;Penning et al, 1991;Armstrong, 1995) verificaram que as maiores produções por área ocorreram em menores alturas da pastagem, porém com reduzido desempenho animal. Nenhuma diferença foi observada dentro de métodos de pastejo (P = 0,5128), comprovando que, em pastagem de azevém, os dois métodos se equivaleram em produção de carne por unidade de área.…”

Section: Ep = Erro-padrão (Se = Standard Error)unclassified

Terminação de cordeiros em pastagens de azevém anual manejadas em diferentes intensidades e métodos de pastejo

Barbosa¹,

Carvalho

Cauduro³

et al. 2007

R. Bras. Zootec.

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RESUMO -Avaliou-se o desempenho de cordeiros em pastagem de azevém anual (Lolium multiflorum Lam.) manejada em duas intensidades (moderada e baixa, 2,5 ou 5,0 vezes o potencial de consumo) e dois métodos de pastejo (lotação rotacionada ou contínua) durante 113 dias. O delineamento experimental foi o de blocos casualizados, em esquema fatorial 2 × 2 × 4 com quatro repetições. Não houve interação métodos × intensidades de pastejo e, portanto, seus efeitos foram analisados de forma independente. A intensidade de pastejo moderada resultou em menor oferta de forragem, menor massa média e menor altura da pastagem. As características qualitativas da forragem também foram afetadas positivamente pela intensidade moderada.A altura e a massa de forragem foram maiores no pastejo sob lotação rotacionada, mas a qualidade da forragem foi melhor nos piquetes de lotação contínua. grazing intensities were represented, respectively, by forage allowance of 2.5 and 5 fold the intake potential. It was used a factorial arrangement (2 intensities × 2 methods × 4 replicates) in a complete randomized block design. There was no interaction among grazing methods and grazing intensities and they were analyzed separately. The moderate grazing intensity provided the lower forage allowance, lower herbage mass and lower pasture height. This intensity affected positively the qualitative characteristics of pasture as well. Regarding the grazing methods, the height and the herbage mass were larger under rotational stocking, while the forage quality was higher under continuous stocking. There was no difference of forage allowance between methods, and the necessary conditions to compare all the variables measured were reached. There were significant differences between average daily gain and stocking rates on both, grazing methods and intensities. The gain/hectare was better under moderate grazing intensity, but no difference was identified under grazing methods for this intensity. The amount of forage available for the animal is the central key for the productivity, despite the grazing method used. Low grazing intensity was considered more appropriate for pasture management because it allows better gain per animal.Key Words: average daily gain, continuous stocking, gain/ha, rotational stocking IntroduçãoO respeito ao ambiente e ao bem-estar animal impõe condições de mercado, uma vez que a sociedade consumidora atual exige produtos de qualidade, produzidos segundo regras éticas e de segurança alimentar. É crescente a demanda de informações e garantias sobre as condições de produção e a origem dos alimentos consumidos, especial-

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Section: Ep = Erro-padrão (Se = Standard Error)unclassified

Terminação de cordeiros em pastagens de azevém anual manejadas em diferentes intensidades e métodos de pastejo

Barbosa¹,

Carvalho

Cauduro³

et al. 2007

R. Bras. Zootec.

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“…Consequently, in swards continuously grazed by cattle, such areas may buffer decline in clover content and maintain reasonably constant annual levels or impose only gradual decline from very high levels. In contrast to cattle-grazed swards, reduction in white clover content in sheep grazed swards can be rapid under continuous grazing (Orr et al, 1990). This is partly accounted for by rapid branching in the early stages of sheep grazing.…”

Section: Grazing Effectsmentioning

confidence: 94%

“…Comparisons are variable, however. Sheep production from grass/clover swards has been less than 75% that of grass swards receiving 400 kg N ha -1 (Orr et al, 1990).…”

Section: Animal Productionmentioning

confidence: 99%

Effects of grass–legume mixtures on the production and photosynthetic capacity of constructed grasslands in Inner Mongolia, China

et al. 2016

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The paper summarises some of the advances which have been made a) in increasing understanding of the grass-legume association, especially grass-white clover, so that the association can be more predictably exploited and b) in overcoming limitations in the use of such mixtures. The contribution which forage legumes make to the N economy of mixtures is reviewed with estimates approaching 400 kg N ha -1 for some. Uptake by grass of legumederived N (N transfer) reduces soil mineral N levels and increases the proportion of fixed N in the total legume N relative to legume monoculture. Although N transfer also causes inconsistent contribution of legume to mixed swards, models of the effect of legume derived N on the interaction between grass and legume are helping to predict likely grass-legume balance, even when grazed.The higher nutritive value and intake of legumes relative to grass is due to a range of factors including faster rate of particle breakdown, faster digestion in the rumen, more nonammonium N reaching the small intestine and higher efficiency of energy utilization although efficiency of N utilization is lower. Poor utilization is not an issue with birdsfoot trefoil and sainfoin due to their herbage having a high content of condensed tannins which protect protein from degradation in the rumen. Breeding programmes using conventional and biotechnological methods are aiming to improve nutritive value such as increasing protein quality and introducing condensed tannins into clovers and lucerne. Breeding of legumes to reduce antiquality factors, such as bloat, is underway. Breeding to reduce oestrogenic effects has been successful in red clover and subclover.Advances are leading to improved legume consistency in mixture including improvement in tolerance to biotic and environmental stress by breeding and increased understanding of the role of companion grasses. Research which underpins management techniques to improve predictability of grass-legume balance is also discussed, including the positive and negative role of the grazing animal.The potential and limitations of grass-legume swards to reduce N loss, including NO 3 leaching, in whole farm systems is evaluated where grass/white clover can reduce leaching by 50% compared with a high fertilizer N system at only 20% reduction in output. Other factors which may result in increased reliance on forage legumes, in addition to the improvements in forage legumes resulting from research, include de-intensification policy decisions to reduce stocking rates, increased uptake of organic farming, increased cost of N fertilizer relative to commodity prices. Shared research effort between countries is advocated to supply adequate resources to solve some of the remaining problems in grass/legume associations and effective technology transfer should include development of decision support systems due to the complexity of the association.

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“…Several studies have shown that herbage intake by sheep grazing in temperate pastures is severely depressed when sward height falls under 4 cm (Allden and Whittaker, 1970;Penning, 1986;Orr et al, 1990). One of the main arguments that could be used to explain reduced intake where there is a low sward height is that the amount that can be taken with each bite is low (Stobbs, 1973;Penning, 1986;Orr et al, 1990). In a mechanistic explanation of reduced intake on short swards, the lower weight of each bite can partly be offset by the animal increasing the number of harvesting bites.…”

Section: Discussionmentioning

confidence: 99%

Herbage intake by Churra ewes grazing at two different sward heights

Valdés¹,

Mantecón²,

Giráldez³

et al. 1995

J. Anim. Feed Sci.

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Herbage intake and some characteristics of diet selected by grazing Churra ewes were studied on two plots of a Lolium-Festuca-Trifolium pasture maintained at two different sward heights (sward heights (SH): 4 cm (SSH) and 8 cm (HSH) in two periods (PE): summer and autumn. Herbage intake was estimated from measurements of faecal output and of digestibility of extrusa samples. With the exception of crude protein content, no significant (P > 0.05) effects of PE nor SH were detected in the chemical composition and digestibility of herbage on offer. Daily herbage intake (g OM/kg live weight) was greater (P ^0.10) on HSH than on SSH and was also greater (P =£ 0.05) in autumn than in summer. Significant effects of PE (P^O.01) and SH (P=%0.05) were obtained in the selection ratios (calculated as the content of each considerate component in extrusa samples divided by its content in the herbage on offer) for all chemical fractions and for digestibility. Except for cellulose, interaction between main factors had a significant (P^ 0.001) effect on the selection ratios.

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Sward composition, animal performance and the potential production of grass/white clover swards continuously stocked with sheep

Cited by 89 publications

References 17 publications

Terminação de cordeiros em pastagens de azevém anual manejadas em diferentes intensidades e métodos de pastejo

Terminação de cordeiros em pastagens de azevém anual manejadas em diferentes intensidades e métodos de pastejo

Effects of grass–legume mixtures on the production and photosynthetic capacity of constructed grasslands in Inner Mongolia, China

Herbage intake by Churra ewes grazing at two different sward heights

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