The effect of maturity and leafiness on the intake and digestibility of alfalfas and grasses fed to sheep

1969 ◽  
Vol 73 (1) ◽  
pp. 145-154 ◽  
Author(s):  
J. E. Troelsen ◽  
J. B. Campbell

SUMMARYThe effect of maturity on the nutritional quality of hay from two alfalfa varieties and four grass species was studied. Each hay was harvested at six different stages of growth, chopped in 4–6 cm lengths, and fed to sheep in quantities of 10% in excess of voluntary intake. The relationship between intake (Y) and digestibility (X) of dry matter was best expressed by regressions of the form: Y = a + b1X + b2X2. The rate of intake declined 1·5 g daily per kg0·75 of body weight per unit decrease in digestibility percentage, and was the same for both alfalfa and grass hays. However, the intake of alfalfa hay was about 10% higher than that of the grass hays of similar digestibility. No differences in the relationship between intake and digestibility (P < 0·05) were observed between the two alfalfa varieties or between the four grass species. When the nutritional quality was expressed as voluntary intake of digestible organic matter daily per kg0·75 of body weight, and time of harvest as day-number of the year, the difference in quality between the six kinds of hay was very small or absent at the beginning of the season (immature to prebloom) and increased toward maturity (dough stage to seed ripe). The decline in quality of alfalfa hay was slower than that of grass hay, and ceased at the mature to overripe stage. On the average, voluntary intake of digestible organic matter declined 0·29 g daily for each day delay in harvest time; this decline varied from 1·2% of the daily intake of digestible organic matter in the beginning of the season to 0·6% at the mature stage. Time of harvest ‘accounted for’ 77–89% of the variation in the quality of the hays. The confounded effect of maturity and leanness on the nutritional quality of the hays was expressed best by concave, second degree polynomial regressions. On the average a unit decline in percent leaves corresponded to a decline of 0·58 g and 0·73 g respectively in the daily intake of digestible organic matter from alfalfa and grass hay. This varied from over 1 g early in the season to less than one tenth of a gram late in the season. The confounded effect of leafiness and growth stage ‘accounted for’ over 75% of the variability in nutritional quality. The relationship between intake and digestibility of the alfalfa and grass hays was used to illustrate how voluntary intake of metabolizable energy (percent of requirement for maintenance) from hay of pure or mixed species may be predicted from in vitro digestibility.

1973 ◽  
Vol 24 (6) ◽  
pp. 889 ◽  
Author(s):  
RF Thornton ◽  
DJ Minson

Eight grasses and six legumes were fed ad libitum at hourly intervals to wethers fitted with large rumen fistulas to determine voluntary intake, apparent digestibility, and the apparent retention time of organic matter in the rumen, as well as the quantity of rumen digesta and the organic matter content of the rumen digesta. The voluntary intake of legumes was 28% higher than that of equally digestible grasses. This difference was caused by a shorter retention time (17%) and a higher amount of organic matter (14%) in the rumen digesta from legume diets than from grass diets. The weight of wet digesta in the rumen of sheep fed on legumes was 7% lower than from those fed on grass. Neither the quantity of digesta nor the quantity of organic matter in the rumen was related to the voluntary intake, digestibility, or retention time of organic matter in the rumen. Number of jaw movements each day and rate of cotton thread digestion were not related to the retention time of the diets either. Daily intake of digestible organic matter (DOMI, g/day) was closely correlated with retention time (RTOM, hr) for the feeds in this study (r = –0.93) and the same relation applied to both temperate and tropical feeds, viz. DOMI = 1276–50.7 RTOM (r=0.96) Differences in voluntary intake between grasses and legumes were attributed to differences in retention time and the density to which the food was packed in the rumen.


1976 ◽  
Vol 86 (2) ◽  
pp. 355-365 ◽  
Author(s):  
M. J. Gibb ◽  
T. T. Treacher

SummaryThe effect of daily herbage allowance on herbage intakes and growth rates lambs grazing perennial ryegrass and red clover was investigated in two experiments. Herbage allowances defined as g herbage D.M./kg live weight (LW)/day were controlled by varying the areas of plots grazed for 2 days by groups of six lambs.In the first experiment five herbage allowances in the range 20–120 g D.M./kg LW/day were offered on two areas of a perennial ryegrass (cv. S. 23) sward that received nitrogen fertilizer applications of 39 or 78 kg N/ha/28 days. In the second experiment five herbage allowances in the range 30–160 g D.M./kg LW/day were offered on perennial ryegrass (cv. S. 23) and red clover (cv. Hungaropoly) swards.Asymptotic curves were fitted to describe the relationship between herbage allowance and daily intake of herbage. In Expt 1 nitrogen fertilizer rates did not affect the yield of herbage or animal performance. In Expt 2 intakes were higher on the clover sward than on the ryegrass sward at the higher herbage allowances.The asymptotic curves to describe the relationship between herbage allowance and growth rate of lambs differed widely between periods. Growth rate of the lambs increased linearly with increase in digestible organic matter intake. Live-weight gain per unit of digestible organic matter intake was higher on the red clover than on the ryegrass.The conclusion is drawn that if the herbage present to ground level is not more than three times the daily intake of the animals, intake of herbage of the animals may bo restricted.


1969 ◽  
Vol 49 (1) ◽  
pp. 119-124
Author(s):  
J. E. Troelsen ◽  
J. M. Bell

Hay of two alfalfa varieties and four grass species harvested at six maturity stages each was fed to sheep. Voluntary intakes were measured in grams of dry matter daily per kg of metabolic size. Samples were ground coarsely and finely and digested in vitro. Fine grinding did not increase the digestibility of immature hay, but with advancing maturity the fine substrate was progressively more digestible than the coarse. This difference was inversely related (P < 0.05) to voluntary feed intake. The regression of voluntary intake of dry matter (g/day/kg0.75 body weight) on the difference of in vitro digestibility of organic matter in finely and coarsely ground substrate was −2.32 g in the alfalfa hay and −4.18 g in the grass hay. The coefficient of variation from regression was 14% in the alfalfa and 17% in the grass hays. Fine grinding had a greater effect on the in vitro digestibility of organic matter than of dry matter. This resulted in a higher significance of the relationship of intake with the effect of grinding on the digestibility of organic matter than on that of dry matter.


1996 ◽  
Vol 44 (2) ◽  
pp. 103-110 ◽  
Author(s):  
J.W. Cone ◽  
A.H. Van Gelder ◽  
A.M. Van Vuuren

The amount of rumen fermentable organic matter (FOM) can be calculated using tables, taking into account the amount of digestible organic matter, the content of fat and fermentation products, and the amount of starch and protein escaping rumen fermentation, or FOM can be calculated using in situ incubations. An in vitro method is described to predict FOM using amylase and other carbohydrate degrading enzymes. FOM estimated by the enzymic method showed a moderate correlation (Rsuperscript 2 = 0.71) with FOM estimated by the in situ method. The relationship could be improved by separating the high crude fibre samples (Rsuperscript 2 = 0.88) from the other samples (Rsuperscript 2 = 0.77). Because degradation rates with the enzymic method were high compared with the assumed rumen passage rates, it proved that FOM could be predicted with a similar accuracy (Rsuperscript 2 = 0.76 - 0.80) by the undegraded fraction after 24 h.


1972 ◽  
Vol 78 (3) ◽  
pp. 355-362 ◽  
Author(s):  
K. W. Moir

SUMMARYGrasses and legumes comprising poor to good quality temperate and tropical species were fed to either cattle or sheep in 36 digestibility experiments. Cell wall in these forages was the ash-free and protein-free residue after sequential extraction with acidpepsin, organic solvents and either water for grasses or ammonium oxalate for legumes. The average amount of cell wall digested per 100 g forage OM was 40·0±0·59 g in grasses and 19·8±1·85 g in legumes. It was considered that within grasses and within legumes the physiology of ruminant digestion, rather than forage quality, was the main determinant of the average amount of cell wall digested and the difference between grasses and legumes was due to interaction of the ruminant digestion process with the physical structure of the cell wall. Of forage factors governing variation about the physiological average, the total cell wall had some effect on the amount of cell wall digested, but the lignin concentration in the cell wall had no effect.Among grasses and legumes the average, apparently undigested, protein-free non-cell-wall component was 6·2±0·13 g per 100 g forage OM. This component and digestible protein relative to total protein varied among different sets of data. It was concluded that only the component of digestible organic matter which was governed by the relative proportions of cell walls and cellular contents was predictable from chemical composition. It was considered that selection in plant breeding should be based on both digestible cell wall and cell-wall content instead of digestible organic matter.


1990 ◽  
Vol 50 (3) ◽  
pp. 425-438 ◽  
Author(s):  
A. J. Rook ◽  
M. Gill

ABSTRACTData on individually recorded silage dry-matter intake (SDMI), concentrate dry-matter intake (CDMI) and live weight of steers and data on silage composition including toluene dry matter (TDM), pH, total nitrogen (N), ammonia nitrogen (NH3-N), volatile fatty acids (VFAs), digestible organic matter in the dry matter (DOMD) and neutral-detergent fibre (NDF) obtained from experiments conducted at three sites were used to obtain simple and multiple linear regressions of SDMI on other variables.Live weight accounted for a high proportion of the variation in intake but this effect could generally be removed by scaling intake by live weight raised to the power of 0·75 (M0·75). CDMI was the most important factor affecting scaled intake in mixed diets. TDM, NH,-N and VFAs all had important effects on SDMI. The relationship of SDMI with TDM was curvilinear suggesting that there is little to be gained in intake terms from wilting to TDM above 250 g/kg. The effect of NH3-N appeared to be related more to its correlation with VFAs than with any other nitrogenous constituent while the VFAs appeared to have a direct effect on SDMI. The effects of N and pH on SDMI were generally small. DOMD and NDF had relatively little effect on SDMI. Significant differences in intercepts between sites were found for most relationships although common slopes were often found.


1996 ◽  
Vol 1996 ◽  
pp. 41-41
Author(s):  
A.T. Adesogan ◽  
E. Owen ◽  
D.I. Givens

Estimates of the metabolisable energy (ME) content of whole crop wheat (WCW) derived using measured energy losses as methane (ELMm) are lacking due to the cost of measuring ELMm. Published ME values of WCW are largely calculated using predicted energy losses as methane (ELMp, Blaxter and Clapperton, 1965) or digestible organic matter content (DOMD) in vivo. However, there appears to be no published information about the accuracy with which DOMD in vivo or ELMp predicts the ME content of WCW. Therefore, this study assessed the validity of such ME predictions by comparing them with ME contents calculated using ELMm.


Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 273 ◽  
Author(s):  
Donato Andueza ◽  
Fabienne Picard ◽  
Philippe Pradel ◽  
Katerina Theodoridou

In mountain areas, hays are the main forage in winter diets for livestock. Barn-dried hays can be an alternative to traditional hays, which are generally characterized by a low feed value. The aim of this study was to compare the feed value of barn-dried hays with that of the fresh forage from a permanent meadow. The study was carried out over three periods during the first growth cycle of the meadow’s vegetation (from 30 May to 3 June, from 13 to 17 June, and from 27 June to 1 July). Fresh forage and barn-dried hays of the same fresh forages were tested for dry matter digestibility (DMD), organic matter digestibility (OMD), and voluntary intake (VI). Both types of forage obtained each period were tested with an interval of 15 days. Chemical composition and OMD of forages did not change (p > 0.05) according to the feeding method. However, the DMD values for barn-dried hays were higher (p < 0.05) than for fresh forages at the end of the cycle. VI and digestible organic matter intake of barn-dried hays were higher (p < 0.05) than that of fresh forages. In conclusion, barn-dried hays obtained from permanent grasslands presented a higher feed value than fresh forages.


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