C. S. W. Reid

Bio: C. S. W. Reid is an academic researcher. The author has contributed to research in topics: Rumen & Reticulum. The author has an hindex of 3, co-authored 3 publications receiving 170 citations.

Effect of intake and feeding frequency on feeding behaviour and quantitative aspects of digestion in sheep fed chaffed lucerne hay

Abstract: Chaffed lucerne hay of 64% apparent organic matter (OM) digestibility was fed to wether sheep under four feeding regimens: two levels of dry matter (D.M.) intake (700 (L) and 1050 (H) g/day) and within each level two feeding frequencies (once a day (daily) and once an hour (hourly)). Three separate groups of sheep were used concurrently: a slaughter group was used to obtain feeding behaviour data and to measure pool sizes and obtain samples from the reticulo-rumen; a digestion group, in which each sheep was prepared with a rumen and a duodenal cannula, was used to measure duodenal digesta flow, rumen microbial growth and reticulo-rumen motility; a balance group was used to measure digestibility and nutrient balances.High D.M. intake increased reticulo-rumen pool sizes and flow rates but it did not affect apparent digestibilities or the proportions of OM, fibre, cellulose, hemicellulose, lipid and nitrogen digested in the stomach and intestines. Increased feeding frequency had a major effect on reticulo-rumen pool sizes but did not affect apparent digestibilities or partition of digestion of non-nitrogenous constituents. Daily feeding resulted in increased total-N flow to the duodenum; however, N retention was significantly greater with frequent feeding. It is suggested that this was due to a more efficient tissue utilization of N.The kinetics of digesta flow within the reticulo-rumen, expressed as fractional flow rates, were studied with data from sheep fed hourly. The fractional inflow, outflow and disappearance rates for OM, fibre, cellulose and hemicellulose did not change with an increase in intake because of an equivalent increase in reticulo-rumen volume. Increasing D.M. intake by 50% resulted in a 24% increase in water intake, a 19% increase in reticulo-rumen water volume, and a 49% increase in water outflow rate. The data suggest that the increased outflow of water was achieved by increasing the net flow of water across the mucosa into the reticulo-rumen, rather than by increasing salivation.There was no difference between treatments in the frequency of reticulo-rumen contractions. It was calculated that for each A sequence contraction, OM flow was 0·26 and 0·37 g and water flow was 4·38 and 0·36 g on L and H intakes respectively. A 50% increase in intake resulted in a 42% increase in OM passage per A sequence contraction. This increased passage with intake was not accompanied by an increase in reticulorumen contraction frequency.

Feed comminution, particle composition and distribution between the four compartments of the stomach in sheep fed chaffed lucerne hay at two feeding frequencies and intake levels

Abstract: Chaffed lucerne hay was fed to wether sheep at two feeding frequencies (once a day (daily) and once an hour (hourly)) and at two levels of dry matter (D.M.) intake (700 (L) and 1020 (H) g/day). Sheep fed daily were slaughtered either prior to eating, immediately after eating ceased or 10 h after eating ceased to compare rumen, reticulum, omasum and abomasum pool sizes and particle size distributions within pools. Effects of level of intake, feeding frequency and time after feeding were confined mainly to the rumen which contained 77–91% of stomach D.M. Once-daily feeding resulted in a 2·6 fold variation in rumen D.M. pool size. Sheep fed hourly had a relatively small rumen and comparatively large reticulum D.M. pool. Diurnal changes in reticulo-rumen particle size pools are discussed in relation to the effectiveness of chewing. Particle size distribution in digesta was estimated by wet sieving. On average the proportion of D.M. retained on a sieve 1 mm or larger comprised 35, 28, 4 and 4% of D.M. in the rumen, reticulum, omasum and abomasum, respectively, D.M. passing a 0·25 mm sieve comprised 40, 46, 57 and 61% of D.M. in the respective organs. The reticulum usually contained significantly less D.M. retained on a 4 mm sieve than the rumen, and reticulum D.M. percentage was usually 3–5 units lower than rumen D.M. percentage. Reticulum digesta composition is discussed in relation to the efflux of particulate D.M. to the omasum. Chemical composition of rumen particulate D.M. retained on sieves > 0·25 mm was comparatively unaffected by intake level and feeding frequency. Analyses of particle composition showed a rapid loss of non cell wall constituents after feeding and an increasing contribution of rumination toward particle size reduction.

Prediction of intake and digestion in ruminants by a model of rumen kinetics integrating animal size and plant characteristics

Abstract: Simulation modelling was used to investigate interactions between forage degradation characteristics, rumen processes and body weight, and to predict the voluntary food intake and digestion of a range of forages. Predicted voluntary intake and digestion agreed well with empirical data, explaining 61 and 70%, respectively, of variance in observed values. Since the data covered a wide range of animal weights and forage qualities, these results suggest that the model is a useful means of integrating the effects of animal and forage variables. Interactions were examined between animal weight and diet quality, as defined by the proportion of potentially digestible cell contents and cell walls and their rates of digestion. Retention time of food in the digestive tract was shown by regression to scale with W⁰·²⁷. The time taken to comminute large fibre particles also scaled with W⁰·²⁷. Longer retention of digesta by large ruminants increases digestive efficiency compared with small animals and would permit them to survive on lower-quality foods. The model showed that maximum intake of metabolizable energy scales with c. W⁰·⁸⁷, greater than the scaling of maintenance with W⁰·⁷³

Factors Affecting the Mean Retention Time of Particles in the Forestomach of Ruminants and Camelids

Abstract: Publisher Summary This chapter discusses the factors that determine the mean retention time (MRT) of fluid and particles in the forestomach of ruminants and camelids. The advantage that forestomach fermenters have over potential monogastric competitors is their superior ability to utilize plant cell walls. The microbial degradation of cell wall constituents is a slow process. To achieve effective cellulose digestion, ruminants and camelids have evolved large fermentation chambers in their stomachs. They retain feed particles substantially longer than fluid in these chambers. This strategy has two consequences: (1) a long MRT of feed particles in the reticulorumen (RR) that improves the utilization of cell-wall constituents and (2) a long MRT restricts feed intake, because the intake of roughage is limited mostly by the capacity of the forestomach. The chapter also explores the many attempts that have been made to predict forage intake in ruminants and to find ways of increasing the intake of roughage.

Ingestion and mastication of feed by dairy cattle.

Abstract: For fiber in dairy cattle diets to be effective it must be masticated initially during feeding and again during rumination. Time spent chewing is directly related to saliva secretion, which helps buffer the rumen environment and optimizes fiber digestion. Reduction in feed particle size occurs during chewing, which is a prerequisite for passage of feeds from the forestomach, but the extent of particle breakdown during chewing depends upon the feed. Manipulating the dietary concentration of plant cell walls or the physical form of forage can alter chewing behavior and rumen function of the dairy cow, thereby optimizing productivity.