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.TMTTJODTTPTTOIST Waldo, Smith & Cox, 1972; Baldwin, Koong & w Ulyatt, 1977;Mertens & Ely, 1979; Black et al. A large amount of information is available con-1981), has identified areas of research which are cerning digestion and metabolism within the reti-likely to yield useful information on the control culo-rumen. Far less is known about the processes processes. These include: the effects of chewing that control breakdown of food residues and their during eating and rumination on particle size repassage out of the reticulo-rumen. The use of duction and fermentation, t...

Effects of Feeding Frequency and Soybean Meal Supplementation of Alfalfa Silage on Duodenal Nitrogen Supply to Sheep

“…Also, FF did not affect digestibility of any fraction. This agrees with findings of Ulyatt et al (1984) and Satter and Baumgardt (1962) who could not detect any effect ofFF on digestibility of alfalfa hay. However, in our earlier studies (Ruiz and Mowat 1987), small increments in DM and OM digestibilities were obtained.…”

“…These improvements resulted from the additive effects of small increments in NDF and ADF digestibilites, and a positive effect on N digestibility. Diets used in this study had a lower concentrate level than those used previously which should benefit fiber digestion (Hoover 1986 Ulyatt et al (1984) and Bunting et al (1987) who could not detect changes in extent or site of cell wall digestion when animals were exposed to FF.…”

Influence du rythme de distribution sur les activités alimentaires et l'évolution journalière du contenu ruminal chez le mouton

“…En revanche, la distribution de l'aliment incite l'animal à manger, même s'il n'a pas ingéré tout ce qui lui avait été distribué précédemment. Le rythme de distribution de l'aliment influence donc l'organisation des activités alimentaires des animaux (Ulyatt et al, 1984 ;Nocek et Braund, 1985).…”

The effect of supplementation with maize starch and level of intake of perennial ryegrass (Lolium perenne cv. Endura) hay on the removal of digesta from the rumen of sheep

“…The effect of soluble carbohydrates in depressing cellulolysis is well documented (El-Shady et al 1961; Terry et al 1969;Mertens & Loften, 1980) and often leads to a depression in voluntary intake. However, the relation between this depression and rumen volume has not been studied in detail.The relation between rumen pool sizes and intake level has been studied by a number of workers, mainly with diets of oat straw (Pearce, 1967) , 1984;Ulyatt et al 1984). The increase in rumen pool size has generally been less than the increase in intake, presumably due to the increase in rate of passage as intake level increased.…”

“…Roughages contain a high level of fibre and since the rate of digestion of fibre is slower than that of other fractions (Van Soest, 1975), factors affecting this rate may thus be implicated in intake control. The effect of soluble carbohydrates in depressing cellulolysis is well documented (El-Shady et al 1961; Terry et al 1969;Mertens & Loften, 1980) and often leads to a depression in voluntary intake.…”