Effect of forage particle length on rumen digesta load, packing density and voluntary feed intake by sheep

1992 ◽  
Vol 43 (6) ◽  
pp. 1321 ◽  
Author(s):  
SG Gherardi ◽  
RC Kellaway ◽  
JL Black

The effect of forage particle length (4 to 101 mm) on packing density of oesophageal extrusa was investigated following ingestion of chopped wheaten hay by sheep. Packing density of oesophageal extrusa from 4 mm hay was greater than that from hay 21 mm and longer; the difference was associated with smaller particle size and a lower modulus of fineness. There was a significant positive correlation between the intake rate of hay by individual sheep and size of extrusa particles for three of the five forage lengths. The effect of packing density of ingested forage on rumen digesta load and voluntary intake was examined subsequently by feeding sheep hay chopped to either 4 or 21 mm lengths. hducing the particle length of hay from 21 to 4 mm resulted in small increases (P < 0.05) in the intake of dry matter (DM) [26.0 cf. 27.8 g per kg runen digesta-free liveweight (RFLW)] and organic matter (OM) (23.8 cf. 25.5 g per kg RFLW). Increases in intake were paralleled by increases (P < 0.01) in loads of both rumen DM (29.7 cf. 33.9 g per kg RFLW, for 4 and 21 mm hay respectively) and OM (25.2 cf. 29.1 g per kg RFLW). The higher digesta load was associated with higher concentrations (P < 0.05) of DM (133.6 cf. 122.5 g per kg total digesta) and OM (114.9 cf. 103.8 g per kg total digesta) in the rumen, but not with a difference in the measured packing density of particulate matter. The increase in the intake of 4 mm hay was totally attributable to the greater DM load of rumen digesta because the fractional outflow rate of particulate matter was lower for the 4 mm hay (0.55 cf. 0.63/day) and the apparent fractional rate of digestion was similar (0.42 cf. 0.43/day) in sheep fed the two lengths of forage.

1989 ◽  
Vol 62 (3) ◽  
pp. 589-599 ◽  
Author(s):  
S. G. Gherardi ◽  
J. L. Black

The effect of post-rumen supply of nutrients on the rumen digesta load and voluntary consumption of roughage by Border Leicester × Merino ram lambs was investigated. A chopped wheaten hay was offered to the ram lambs (n 24), whose nutrient intake was altered by infusing into the abomasum a liquid supplement, containing reconstituted cow's milk, sodium caseinate, minerals and vitamins, for a period of at least 30 d. Either two or three lambs were allocated by live weight to each of ten rates of nutrient supplementation. The lambs were slaughtered at a target live weight of 31 kg. Voluntary intake of hay was estimated over the last 7 d of feeding. The amounts of digesta and organic matter (OM) in the rumen were measured by emptying after slaughter. The particle size distribution of the digesta was measured by wet sieving and the fractional outflow rate of particulate matter by reference to the marker lignin. Growth rate of the lambs increased linearly as total energy infused increased. The linear increase in growth rate indicated that roughage was not substituted for infused nutrients on a direct energy basis. OM intake from hay declined linearly as the amount of nutrients infused increased. The decline in intake was associated with a decline in both total digesta and the amount of rumen OM. Both the fractional digestion rate of OM and the fractional outflow rate of particulate matter from the rumen were unaffected by the amount of nutrients infused. The results indicated that the rumen digesta load of young sheep fed on a single roughage is directly related to their energy deficit, that is the difference between the capacity of the animals to use energy and the energy available to them for metabolism.


1978 ◽  
Vol 26 (2) ◽  
pp. 143-150 ◽  
Author(s):  
J. M. Wilkinson ◽  
Ines M. Penning ◽  
D. F. Osbourn

ABSTRACTWhole-crop maize was harvested at 20% (L), 29% (M) and 38% (H) dry-matter (DM) content, chopped to 7·67 mm (F) or 33·3 mm (C) average particle length and ensiled. The six silages were offered ad libitum to 36 entire male calves (initially 96 kg live weight), together with supplements of urea and dried ryegrass, for 42 days. Voluntary intake and the apparent digestibility of the diets were measured. Intake of DM was not affected by the DM content of the silages, but was higher for F than C by 6·6% (P<0·01). Apparent digestibility of DM, organic matter and cell walls decreased with increasing silage DM content (P<0·001) and was higher for F than C (P < 0·01).


1991 ◽  
Vol 117 (1) ◽  
pp. 111-120 ◽  
Author(s):  
B. M. F. Domingue ◽  
D. W. Dellow ◽  
T. N. Barry

SUMMARYPrairie grass (Bromus catharticus) straw (13·7 g N/kg DM) was fed ad libitum to six goats and seven sheep kept in metabolism cages at Palmerston North, New Zealand in 1986 and 1987.Goats had greater voluntary feed intake (VFI) (56 v. 36 g DM/kg W0·75 per day), greater apparent DM digestibility (36·8 v. 32·6%) and a larger rumen pool of DM and liquid (W0·75) than sheep. Goats also had greater apparent digestibility of fibre, especially of lignin, and greater rumen fractional degradation rates (FDR) of cellulose, hemicellulose and lignin. Goats had a higher rumen ammonia concentration (115 v. 80 mg N/l), lower rumen pH (6·73 v. 6·90), a smaller proportion of large particles and greater proportion of small particles in rumen contents than sheep. Passage through a 1 mm sieve was established as the threshold particle size to have a high probability of leaving the rumen in both goats and sheep. Voluntary water intake/unit DM consumed was lower in goats than in sheep and, whilst rumen fractional outflow rate (FOR) of water and particulate matter also tended to be lower in goats, the difference was not significant. Irreversible loss rate of rumen NH3 and the amount of N calculated as recycled to the rumen, both expressed as mg N/kg W0·75 per day, were greater for goats than for sheep.It was concluded that the ability of goats to maintain a higher rumen NH3, concentration than sheep, their larger rumen pool and the higher proportion of small particles in rumen contents were all contributing factors to their greater VFI and fibre digestion of this low-quality roughage.


1970 ◽  
Vol 75 (3) ◽  
pp. 369-373 ◽  
Author(s):  
R. J. Haggar ◽  
M. B. Ahmed

SUMMARYTwenty-seven sheep feeding trials were carried out on freshly cut Andropogon gayanus, fed daily during three wet seasons, 1966–8.In each year, dry-matter voluntary intake and digestibility were highest during the first part of the growing season and declined with advancing maturity of the herbage. However, at the time of ear emergence in early October, there were small increases in voluntary intake of dry-matter and crude protein digestibility, although further decreases followed after mid-October.Determinations of in vitro digestibility indicated that elongating stems during early October were at least as digestible as leaves.Seasonal changes in crude protein digestibility were much greater than changes in dry-matter digestibility; seasonal changes in feed intake were intermediate. Voluntary feed intake was related to dry-matter digestibility.Voluntary feed intake and digestible crude protein were both closely related to the crude protein content of the forage. It was concluded that crude protein is a useful criterion for predicting nutritive value.


1977 ◽  
Vol 24 (2) ◽  
pp. 227-235 ◽  
Author(s):  
W. A. McIlmoyle ◽  
J. C. Murdoch

SUMMARYTwo 7 × 7 Latin square experiments were carried out with British Friesian steers (mean initial live weight 360 kg). In Experiment 1 the effects of different levels of dried grass or concentrate on the intake of silage dry matter (DM) were compared, and in Experiment 2 the effect of a supplement containing various proportions of dried grass: concentrate on the intake of silage DM was examined. In both experiments the digestibility of the ration and the rate of passage of digesta were measured.In Experiment 1, supplementation depressed intake of silage DM, the difference being significant (P<0·05) at 5·0 and 7·5 kg/day, but there were no significant differences in silage intake between supplements given at the same level. Intake of silage was also significantly lower (P<0·05) in Experiment 2 when a supplement was offered, but differences between supplements were not significant. Total DM intake was increased significantly (P<00·5) by supplementation in both experiments. Supplementation increased energy digestibility but decreased crude fibre digestibility. In Experiment 1 nitrogen digestibility was significantly lower (P<0·05) with dried grass than with concentrate supplementation, but in Experiment 2 supplementation increased the digestibility of nitrogen. In both experiments the mean retention time was shorter, the time for the highest rate of excretion of stained particles was lower, and the maximum rate of excretion higher for dried grass than for silage.


1972 ◽  
Vol 12 (54) ◽  
pp. 21 ◽  
Author(s):  
DJ Minson

The digestibility and voluntary intake of Chloris gayana, Digitaria decumbens, Panicimum maximum var tricboglume, Paspalm dilatatum, Pennisetm Clanhtinum, and Setaria splendih were measured with sheep in metabolism pens. All grasses were grown under the same conditions and cut at the same time. Each grass was cut after growing for 28, 70, and 98 days in the summer and then again (except for P. dilatatum) after 42, 70, and 105 days in the following autumn. Four successive 28-day regrowths of each grass (two cuts only for P. dilatatum) were also harvested during the summer. All 55 cuts were artificially dried and fed at the same time, each cut being fed to eight sheep. Differences in dry matter and organic matter digestibility between grass species were relatively small with a maximum mean difference of six digestibility units between S. splendida and P. clandestinzrm. For the 28-day regrowths S. splendida was 5.1 digestibility units higher but with the more mature regrowths the difference was 6.8 digestibility units. The mean voluntary intake of dry matter of S. splendida and P. clandestinum was 9 and 11 per cent lower than that of D. decmbens (P<0.01) with the largest differences in voluntary intake between grasses occurring at the mature stages of growth. Large differences were found between grass species in both the slope and intercept of regressions relating voluntary intake to dry matter digestibility.


1974 ◽  
Vol 82 (3) ◽  
pp. 419-422 ◽  
Author(s):  
M. C. Rees ◽  
D. J. Minson ◽  
F. W. Smith

SUMMARYPangola grass grown with and without sulphur fertilizer was cut as a 7-week regrowth to measure voluntary intake and digestibility by sheep. To determine the extent of a simple sulphur deficiency half the sheep on each feed were supplemented with 0·6 gsulphur daily. Retention time of feed in the reticulo-rumen and proportion of feed digested anterior to the duodenum was also determined.Sulphur fertilizer increased the sulphur content of the pasture from 0·09 to 0·15%, voluntary intake of dry matter from 44·4 to 64·1 g/kg W0·75/day and dry-matter digestibility from 55·2 to 60·2%. Sulphur fertilizer reduced the retention time in the reticulo-rumen by 16% and increased the extent of dry-matter digestion before the duodenum from 13 to 34%.Feeding a sulphur supplement increased dry-matter digestibility of the low sulphur feed to that found with sulphur fertilized pangola grass but only accounted for 63% of the difference in voluntary intake.It was concluded that fertilizer sulphur leads to large increases in both voluntary intake and digestibility of sulphur deficient grass and that the improvement in nutritive value may be more than can be achieved by feeding a sulphur supplement.


1998 ◽  
Vol 67 (3) ◽  
pp. 559-566 ◽  
Author(s):  
A. Ferret ◽  
J. Gasa ◽  
G. Caja ◽  
P. Prió

AbstractForty-eight pregnant Manchega dairy ewes bearing twins or singles penned in groups of six during the last 11 weeks of gestation were used to study the effects offorage type (Italian ryegrass hay or alfalfa hay) and number of foetuses (one or two) on voluntary dry-matter (DM) intake and digesta kinetics. Hays were supplemented with 0·6 kg/day of concentrate. When measured directly for group-fed ewes, forage DM intake was affected byforage type (P < 0·01), whereas litter size had no significant effect. An internal (rumen-undegradable DM) and an external (chromium III oxide) marker were also used to determine intake of individual ewes to account for errors in diagnosing litter size. Estimated DM intake confirmed the effect offorage type on DM intake and revealed the effect of litter size on food intake (F < 0·05). Forage type also affected chromium III oxide fractional outflow rate and flow of undegradable DM, whereas litter size only had an effect at the end of pregnancy by reducing hay intake, rate of passage and digesta flow mainly with alfalfa diets. In conclusion, DM intake, rate of passage and digesta flow was higher with alfalfa hay than with ryegrass hay, in spite of the similar DM apparent digestibilities of both hays. Furthermore, litter size affected DM intake at the end of pregnancy causing an intake decline, which was greater with alfalfa hay than with ryegrass hay.


1984 ◽  
Vol 35 (6) ◽  
pp. 831 ◽  
Author(s):  
PA Kenney ◽  
JL Black ◽  
WF Colebrook

The effects of dry matter content and particle length of forage on potential intake rate and preference by sheep were investigated using six animals held in metabolism cages. In experiment 1, freshly harvested kikuyu grass (Pennisetum clandestinum) in its vegetative state was mixed in different proportions with similar material that had been oven-dried to form 15 diets ranging in dry matter content from 15 to 94%. Intake rate of wet matter decreased from 60 to 14 g/min as dry matter content increased, whereas the intake rate of dry matter increased from 9 to 14 g/min as the dry matter content of forage rose to about 40% but remained relatively constant thereafter. In experiment 2, undried kikuyu grass was eaten faster and formed a greater proportion of total intake than did dried kikuyu when expressed on a wet matter basis, but the amount of dry matter consumed from each forage was similar when they were offered together in separate containers. Kikuyu chopped to 10-mm length was eaten faster and was also preferred over kikuyu cut to 40 mm, irrespective of its dry matter content. Factors other than intake rate such as taste, odour or feel did not contribute markedly to the preference for either undried or dried kikuyu. Equations developed previously using results from dried forages predicted preference from intake rate quite well for dried forage but not for undried forage. It is suggested that the intake rate of dried forages may be a useful predictor of the preference for dry matter with forages containing any proportion of moisture, but further research is needed.


1991 ◽  
Vol 42 (4) ◽  
pp. 585 ◽  
Author(s):  
SG Gherardi ◽  
JL Black ◽  
WF Colebrook

The effect of either an increase or a decrease in palatability on both long-term intake and preference for a wheaten hay was studied using two groups of sheep. Quantitative assessments of palatability confirmed that it was possible either to increase the palatability of 17 mm length hay by treating it with a combination of butyric acid plus monosodium glutamate or to decrease the palatability of 6 mm length hay by treating it with MgO. The voluntary intake of hay treated with butyric acid plus monosodium glutamate was 10% higher than that of the untreated hay when offered singly to sheep over 25 days. The increase in intake of the treated hay was associated with an increase in the apparent fractional rate of digestion in the rumen. There was no difference in voluntary intake between hay treated with MgO and untreated hay, even though there was a reduction in the apparent digestibility of the treated hay. The addition of MgO resulted in a decrease in the apparent fractional rate of digestion in the rumen which was compensated for by an increase in rumen digesta load. The palatability of a forage did affect its long-term preference, as determined by offering treated and untreated forages together in separate containers for 25 days. The sheep demonstrated a preference for hay treated with butyric acid plus monosodium glutamate (77 cf. 23%) and an aversion to hay treated with MgO (23 cf. 77%). The results indicated that palatability had little effect on the voluntary intake of a wheaten hay when it was offered as the sole forage to sheep. However, when offered a choice between forages, animals consumed significantly more of the more palatable forage.


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