Endoscopic Observations of Digesta Transfer From the Reticulo-Rumen to Omasum of Cattle

McBride, B.W.; Milligan, L. P.; Turner, B. V.

doi:10.4141/cjas84-168

Cited by 22 publications

(14 citation statements)

References 5 publications

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“…These results indicate that reticular contractions have a role in discriminating between particles of the same length but with different densities and in preventing large particles from escaping from the RR. This suggestion is plausible when it is realized that the size of the opening of the ROO may not entirely be responsible for the small amount of large particles which ultimately escape from the RR (McBride et al 1983(McBride et al , 1984. In addition, and Dardillat and Baumont (1992) speculated that small dense particles may be trapped in the reticular cells.…”

Section: Role Of the Reticulum In Selective Retention Of Particles Inmentioning

confidence: 99%

Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle

Okine¹,

Mathison²,

Kaske³

et al. 1998

Can. J. Anim. Sci.

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. 1998. Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle. Can. J. Anim. Sci. 78: 15-21. Simultaneous abolition of the motility of the ruminoreticulum (RR) and digesta passage from the RR by bilateral vagotomy indicate that the motility of the RR coordinated with quiescence of the reticulo-omasal orifice (ROO) are prerequisite for caudal movement of digesta from the RR and forestomach. Rate of passage is of importance in ruminant animals since it is related to maximal voluntary feed intake, extent of digestion of the diet, amount of protein which bypasses the rumen, efficiency of microbial growth, extent of methane loss, and susceptibility of animals to bloat. In a series of studies, we clarified the roles of frequency, pressure and duration of reticular contractions and the function of the ROO in controlling digesta flow from the rumen in response to changes in diets, environmental conditions and physiological status. Variability in amount of NDF and OM transferred per contraction suggests that frequency of reticular contraction is not the rate-limiting step in digesta passage from the rumen. This concept is supported by our finding that the relaxation of the ROO is not always coincidental with reticular electromyographic activity in solid meal-fed relative to milk fed sheep. The magnitude of reticular pressure may not precisely control digesta passage through the ROO as the amount of OM and NDF associated with each centimetre of pressure during contraction varies from 1.2 to 1.4 and from 0.9 to 2.5 g. On the other hand, the amount of OM and NDF passed per second of reticulum contraction varies only from 0.3 to 0.6 and from 0.2 to 0.3 g, respectively, in cattle. In addition, a 38% decrease in mean retention time of particulate matter in the rumen was associated with a 14% increase in duration of reticular contraction in cattle. Similarly, quiescence of the ROO increased from 2.9 to 3.3 s in sheep when feed intake increased from maintenance to twice maintenance. We suggest that duration of reticular contractions may be more closely related to digesta flow than is either frequency or pressure changes. We also suggest that the ruminant animal can influence reticular contraction characteristics and duration of the quiescence of the ROO in response to various stimuli and that reticular contractions are coordinated with other diet and physiological demands for optimal transfer efficiency of digesta from the RR.Key words: Digesta passage, reticular contractions, reticulo-omasal orifice, electromyographic activity Okine, E. K., Mathison, G. W., Kaske, M., Kennelly, J. J. et Christopherson, R. J. 1998. État actuel des connaissances sur le rôle du réseau et de l'orifice réseau-feuillet dans la régulation du transit du digestat rumino-réticulaire chez les ovins et chez les bovins. Can. J. Anim. Sci. 78: 15-21. La suppression simultanée de la motricité du segment rumen-réseau (RR) et du transit du digestat à partir d...

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Section: Role Of the Reticulum In Selective Retention Of Particles Inmentioning

confidence: 99%

Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle

Okine¹,

Mathison²,

Kaske³

et al. 1998

Can. J. Anim. Sci.

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“…A rapid exchange of contents between the reticulum, atrium and reticulum occurs at each reticular contraction, resulting in drainage towards the reticulum of the fluid content from the ventral sac (Waghorn and Reid, 1977). Emptying of the reticulum towards the omasum occurs in a pulse at the end of the second reticular contraction followed by reflux (McBride, 1984;Deswysen, 1985;Dardillat, 1987 Sutherland (1988), suggest that the high density of the fine particles causes them to settle out and accumulate in the ventral part of the reticulum where they are most likely to be evacuated through the reticulo-omasal orifice (ROO). Reid (1984) suggests that the contents may be canal- (Ehrlein, 1980;McBride, 1984;Dardillat and Baumont, 1992).…”

Section: Introductionmentioning

confidence: 99%

“…Emptying of the reticulum towards the omasum occurs in a pulse at the end of the second reticular contraction followed by reflux (McBride, 1984;Deswysen, 1985;Dardillat, 1987 Sutherland (1988), suggest that the high density of the fine particles causes them to settle out and accumulate in the ventral part of the reticulum where they are most likely to be evacuated through the reticulo-omasal orifice (ROO). Reid (1984) suggests that the contents may be canal- (Ehrlein, 1980;McBride, 1984;Dardillat and Baumont, 1992). Flow through an orifice Flow of reticular content through an orifice the size of the ROO is rapidly arrested by the formation of a plug of particulate matter.…”

Section: Introductionmentioning

confidence: 99%

Physical characteristics of reticular content in the bovine and consequences on reticular outflow

Dardillat

Baumont²

1992

Reprod. Nutr. Dev.

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“…Além disso, observações endoscópicas do orifício retículo-omasal sugerem que partículas de até 10 mm de tamanho podem sair do RR sem qualquer resistência, segundo McBRIDE et al (1984). Outro caso mais conflitante ocorre quando dietas são completamente moídas e, praticamente, todo o material no RR é inferior ao "tamanho crítico".…”

Section: Matéria Seca Acumulada (R) Retida (%)unclassified

Características físicas da digesta de bezerros provenientes de rebanhos leiteiros alimentados com dietas contendo diferentes níveis de concentrado

Pereira¹,

Freitas²,

Queiróz³

et al. 1999

R. Bras. Zootec.

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RESUMO -Este trabalho foi realizado para avaliar as características físicas da digesta ao longo do trato gastrintestinal e examinar a concepção de "tamanho crítico" de partículas que escapam do retículo-rúmen (RR), em bezerros de rebanhos leiteiros, submetidos a dietas com diferentes níveis de concentrado. Trinta e dois bezerros machos não-castrados, metade holandeses PC e metade mestiços (Holandês x Zebu), foram abatidos com idade média seis meses e 190 kg PV, após jejum de 16 horas. As dietas, fornecidas à vontade, foram constituídas de feno de capim coast-cross e diferentes níveis de concentrado(milho moído, farelode soja e sal mineral): 45,0; 60,0; 75,0; e 90,0% de concentrado na ração. Os conteúdos do RR, omaso (OM), abomaso (ABO), intestino delgado (ID) e intestino grosso (IG) foram amostrados para avaliar o tamanho médio de partícula (TMP), o módulo de finura (MF) e a resistência relativa média (RRM) ao escape e examinar a concepção de um "tamanho crítico" de partículas que abandonam o RR. A ingestão de dieta com níveis crescentes de concentrado não influenciou o TMP e o MF, já que as partículas escaparam do RR. Portanto, o tamanho das partículas do IG poderia representar o tamanho das partículas que escapam do RR. Neste estudo, mais de 80% das partículas presentes no RR foram inferiores ao tamanho considerado crítico ao escape, indicando que a redução do tamanho, embora seja pré-requisito, não foi o passo limitante que regula a saída de material do RR. A resistência relativa da digesta ao escape do RR cresce à medida que as partículas são maiores, porém a RRM decresce com níveis crescentes de concentrado na dieta.Palavras-chave: bezerros, nível de concentrado, tamanho de partícula, trato gastrintestinal Physical Characteristics of the Digesta of Dairy Bull Calves Fed Diets with Different Levels of ConcentrateABSTRACT -This work was carried out to evaluate the physical characteristics of the digesta throughout the gastrointestinal tract and to exam the conception of critical particle size that escape from the reticulum-rumen (RR), in the dairy bull calves fed diets with different concentrate levels. Thirty two dairy bull calves, one half straightbred Holstein and half crossbreed Holstein-Zebu, slaughtered with average six months of age and 190 kg LW, after fasting for 16 hours. The diets fed libitum were constituted of coast-cross hay, and of different concentrate levels (ground corn, soybean meal and mineral salt): 45.0, 60.0, 75.0, and 90.0 of concentrade in diet. The content of RR, omasum (OM), abomasum (ABO), small (SI) and large intestine (LI) were sampled to evaluate the average particle size (APS), modulus of fineness (MF) and average relative resistance (ARR) to escape, and to exam the critical particle size conception that escaped from the RR. The intake of diet with crescent levels of concentrate did not influence the APS and the MF, as the particles already escaped the RR. Consequently, the particle size of the LI could represent the particle size that escape RR. In this study, more than 80% of...

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Endoscopic Observations of Digesta Transfer From the Reticulo-Rumen to Omasum of Cattle

Cited by 22 publications

References 5 publications

Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle

Current understanding of the role of the reticulum and reticulo-omasal orifice in the control of digesta passage from the ruminoreticulum of sheep and cattle

Physical characteristics of reticular content in the bovine and consequences on reticular outflow

Características físicas da digesta de bezerros provenientes de rebanhos leiteiros alimentados com dietas contendo diferentes níveis de concentrado

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