Herbage as a source of digestible organic matter and digestible nitrogen for the grazing sheep.

1961 ◽  
Vol 12 (4) ◽  
pp. 689 ◽  
Author(s):  
JE Vercoe ◽  
DE Tribe ◽  
GR Pearce

An experiment is reported in which the digestible organic matter and digestible nitrogen intakes of Corriedale wethers grazing on improved pastures in a Mediterranean- type environment 1%-ere measured by the faecal index method from August 1957 to August 1958. The mean digestible nitrogen intake fell from a maximum of 50 g/clay in the spring to a minimum of 6 g/day in the late summer, and reached an autumn maximum of 13 g/day before falling to a winter minimum of 8 g/day. The mean digestible organic matter intake fell from a maximum of 1500 g/day in the spring to a summer minimum of 600 g/day, rose again to an autumn maximum of 1000 g/day, and fell again to a winter minimum of 600 g/day. The results are discussed in relation to the theoretical maintenance requirements of the sheep and the nutritional value of herbage.

1963 ◽  
Vol 5 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald ◽  
G. W. Reid

SUMMARYThe mean daily digestible organic matter intake (D) of each of 47 adult sheep during a grazing period of mean length 48 days was estimated by the chromium sesquioxide/faecal nitrogen technique. Mean live-weights (W) and mean daily weight gains (G) were also measured.The regression of D on W and G, and the underlying or functional relationship between D, W and G were both estimated. From the underlying relationship, the preferred equation, the maintenance requirement of a 100 lb. sheep at pasture is estimated to be 1·02 lb. digestible organic matter daily. This value is 24% higher than the corresponding value for housed sheep obtained previously by us.This result is compared with other estimates of the energy cost of grazing and it is concluded that further work is needed in order to define those circumstances which elevate the maintenance requirements of grazing animals.


1963 ◽  
Vol 5 (2) ◽  
pp. 119-129 ◽  
Author(s):  
J. L. Corbett ◽  
J. P. Langlands ◽  
G. W. Reid

SUMMARY1. The intakes of herbage organic matter (OM) and digestible organic matter (DOM) by twenty dairy cows were measured during two periods of strip grazing on one pasture, in spring and late summer of the same year.2. Results from the first 5-day measurement period in the spring suggested that intakes at this time were restricted primarily because the cows had difficulty in gathering the short herbage. Measurements on ten of the cows continued during a further 5 weeks while the digestibility of the OM of grazed herbage declined from about 80 to 68%. There was a fall of about 20% in DOM intake by the cows during this period; one-quarter of the fall could be ascribed to a reduction in OM intake and the remainder to the decline in digestibility as such.3. Intakes were measured during two weeks in late summer and were compared with those measured during two weeks in the spring when the digestibility of the grazed herbage was similar. Intakes of DOM expressed as lb./lb. live-weight0·73 were the lower by about 10% in the late summer, or by from 10 to 20% in terms of DOM available for production when allowance had been made for maintenance requirements. This finding is discussed in relation to practical experience of the feeding value of autumn grass.


1975 ◽  
Vol 85 (2) ◽  
pp. 337-343 ◽  
Author(s):  
V. A. Oyenuga ◽  
F. O. Olubajo

SUMMARYThe organic-matter intake and the digestibility of grazed tropical pasture mixtures were assessed by the chromic oxide-faecal organic matter-nitrogen technique in five digestion trials. The pasture treatments were designated as: H, Cynodon nlemfuensis var. robustus in a mixture with the legumes Centrosema pubescens and Stylosanthes gracilis; J, Pennisetum purpureum in a mixture with the two legumes in H; K, treatment J plus Panicum maximum; L, a mixture of all the grass and legume species in treatments H, J and K.The mean organic-matter digestibility of the herbages was determined in indoor digestion trials during the experimental period and varied from approximately 60·0 ± 1·73% to 62·7 ± 4·18% in treatments K and H respectively, with treatments J and L falling between these two values. The mean digestibility of the herbage as grazed, however, was approximately 66·8 ± 1·72, 69·7 ±7·68, 67·1 ± 4·40 and 67·4 ± 4·15 % for treatments, H, J, K and L respectively.The estimated mean intake of organic matter was somewhat lower, while that of the digestible organic matter was appreciably lower than those reported for animals of corresponding live weights in temperate countries. Grazed pastures were better digested by 4·1 digestibility units in treatment H, by 7·1 in both J and K, and by 5·3 units in L, compared with the indoor digestion trials.More intensive studies are still needed to warrant any justifiable conclusion as to whether the low intake of herbage by tropical cattle is due primarily to the high crude fibre and the low nutritional values of the pastures, or to the inherent capacity of the animals conditioned to grazing poor·quality pastures.


1964 ◽  
Vol 15 (4) ◽  
pp. 676 ◽  
Author(s):  
LJ Lambourne

Estimates have been made of the feed intake of wethers that received implantations of 60 mg thyroxine every 3 months, and of untreated sheep, grazing together. The estimated intake of digestible organic matter (D.O.M.) by treated wethers was higher than that of controls in 24 out of 27 measurement periods. The difference in feed intake was least in the iirst month after implantation, when the treated sheep lost weight, and greatest in the second and third months when the treated sheep were regaining weight. The overall increase in intake resulting from thyroxine treatment (20–25%) was greater than the increase in wool production (7% greasy weight, 3-7 % clean weight), and the efficiency of wool production was therefore lower in thyroxinetreated wethers. From the relationships between feed intake and rate of weight change it was concluded that in the month after implantation, when pulse rates indicated a substantial rise in metabolic rate, the maintenance feed requirement was raised from about 560 g to about 780 g D.O.M. per day. Observations in two winters with recently shorn sheep gave estimates of maintenance requirements for untreated wethers ranging from 850 to 1300 g D.O.M. per day. During recovery from repeated thyroxine implantation the wethers gained in weight no more efficiently than the controls. The mechanism of action of exogenous thyroxine is discussed in the light of these and other data.


1968 ◽  
Vol 48 (3) ◽  
pp. 373-381
Author(s):  
J. E. Troelsen ◽  
P. I. Myhr ◽  
R. W. Lodge ◽  
M. R. Kilcher

A system for rating the quality of hay by sight, touch and smell was designed and tested. Seven sensory criteria were defined and rated independently on a scale from one to nine in direct relation to their assumed nutritional merit. Hays of different quality were obtained from four grasses and two alfalfas, each harvested at six maturity stages. Each hay was rated independently by five judges. The ratings did not differ (P < 0.05) between judges, but significant differences and interactions occurred between crops, maturity stages, and sensory criteria.Each hay was fed to sheep, and its nutritional value was determined as the voluntary consumption of digestible organic matter (grams consumed daily per kg of metabolic size—weight0.75). The correlation between voluntary consumption and the ratings of the sensory criteria in each hay was generally significant (P < 0.01) for composition, growth stage, color and texture, but not for freshness, odor and cleanness. The three last criteria varied little in the hays studied; therefore, it could not be concluded that they were unimportant in sensory evaluation of hay in general.The variability in voluntary intake "accounted for" by ratings of the seven sensory criteria ranged from 59 to 90% in the different kinds of hay, and 65% when the hays were pooled. When the hays were rated by composition and color only, these criteria "accounted for" 48 to 77% of the variability in intake, but only 38% when the hays were pooled. Coefficients of variation from regression for the pooled ratings were 23% for the seven sensory criteria, 30% for composition and color alone, and 38% from the mean for all seven criteria.


1966 ◽  
Vol 6 (20) ◽  
pp. 96 ◽  
Author(s):  
WR McManus ◽  
GW Arnold ◽  
ML Dudzinski

The results of a three-year experiment with Merino wethers grazed at four stocking rates were examined. There were consistent differences between individual sheep at all times of the year in their intake of digestible organic matter (DOMI), clean wool production (WP), and in their efficiency of conversion of food to wool (E). Within stocking rates there were no consistent relationships between DOMI and WP.


1998 ◽  
Vol 38 (1) ◽  
pp. 23
Author(s):  
R. M. Dixon ◽  
E. S. Garcia ◽  
J. A. Domingo ◽  
J. H. G. Holmes

Summary. The seeds of lablab (Lablab purpureus) and lupin (Lupinus angustifolius) were investigated as supplements for young sheep. In experiment 1, rumen-cannulated sheep were offered low quality roughage ad libitum alone or supplemented with about 5, 10 or 20 g/kg liveweight whole lupin or lablab seed. Rumen ammonia concentrations were increased by each level of both supplements, and the increases were greater with lupins than with lablab. The pH of rumen fluid was decreased by both supplements, particularly when the higher levels were fed. Dry matter of broken seeds of both legume species rapidly disappeared from synthetic fibre bags incubated in the rumen. Roughage dry matter disappearance from synthetic fibre bags decreased (P<0.05) when 20 g/kg liveweight lupins was fed, and this level of both supplements reduced (P<0.05) roughage intake. Total dry matter intake was increased more by lablab than by lupins, but dry matter and organic matter digestibility tended to be increased to a lesser extent by lablab. Overall, digestible organic matter intake and liveweight gain were increased to similar extents by both supplements. Wool growth was lower (P<0.05) with lablab than lupins, particularly at the highest level of supplementation, suggesting that availability of some amino acids was lower with lablab supplement. In experiment 2, rumen-cannulated sheep were fed low quality roughage ad libitum and supplemented with about 10 g/kg liveweight of either lupin or lablab seed. Lectins and protease inhibitors present in the lablab seed disappeared rapidly from synthetic fibre bags incubated in the rumen. In conclusion the nutritional value of lablab seed as a supplement for sheep fed low quality roughage was similar to that of lupin seed for liveweight gain, but was lower for wool growth.


1976 ◽  
Vol 16 (81) ◽  
pp. 555
Author(s):  
RA Spurway ◽  
DA Hedges ◽  
JL Wheeler

The quality and production of forage oats (Avena sativa cv. Acacia) sown on five occasions between late summer and late autumn was measured in an experiment near Armidale, New South Wales. Additional treatments were nil vs. 71 kg ha-1 nitrogen (N) and non-irrigated vs. supplementary irrigation. Nitrogen fertilizer did not significantly affect plant establishment, or the dry matter or digestible organic matter production from any sowing. Plant establishment declined linearly in association with reductions in the mean ambient temperature during the ten days after sowing. Crops sown on February 25 and March 13 produced at least 35 per cent more forage (P < 0.05) with irrigation than dryland crops but with all later sowings the effect of irrigation was not significant. Early sown crops contained up to 36 per cent senescent leaf and 44 per cent dead leaf in August. Organic matter digestibility contents of green and senescent forage differed little and always exceeded 69 per cent, but that of the dead leaf was at times as low as 45 per cent. Equations are presented relating digestible organic matter available in irrigated and non-irrigated treatments to the length and mean temperature of the growth period.


1965 ◽  
Vol 5 (19) ◽  
pp. 396 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
ML Dudzinski

Data from an experiment described by Arnold, McManus and Bush (1964) were used to examine the efficiency of wool production of sheep grazing at different stocking rates. Large differences were found between seasons and between stocking rates in the gross efficiency of wool production (GE), in estimated maintenance requirements (MR), and in an activity index (a). The seasonal pattern for GE, MR, and a was for highest GE and lowest MR and a to occur in late spring. MR and a rose in summer, declined in autumn, and rose in winter following shearing. The maximum value of MR was nearly twice the minimum value. With increased stocking rate the mean annual GE decreased and MR and a increased. The maximum effect recorded was a 34 per cent decrease in GE and a 50 per cent increase in MR for the year. The relations between GE and MR was curvilinear. Possible causes of changes in MR are discussed and the paucity of evidence on stress mechanisms in grazing sheep is pointed out. The use of production data for evaluating pastures is discussed in the light of these results.


1963 ◽  
Vol 5 (1) ◽  
pp. 1-9 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald ◽  
J. D. Pullar

SUMMARYEight adult ewes were fasted for 114 hr. During the last 48 hr. the heat emission of each sheep was measured by direct calorimetry and was found to be 35·2 kcal./kg.0·87/24 hr., that is, 973 kcal./24 hr. for a sheep of 45·4 kg. (100 lb.) live-weight. From this value it is estimated that the 100 lb. sheep would require daily 0·79 lb. digestible organic matter (DOM) from pasture herbage for maintenance.In a second experiment, 49 adult sheep were kept indoors and fed on fresh herbage for a period of 72 days. Measurements were made of the mean daily DOM intake (D), mean live-weight (W) and mean daily weight gain (G) of each sheep. The regression of D on Wk and G, and the underlying or functional relationship between D, Wk and G were both estimated for k = 0·73 and k = 1·0. From the underlying relationships, the preferred equations, the maintenance requirement of a 100 lb. sheep was estimated to be 0·82 lb. DOM daily. This value and those calculated for other live-weights are approximately two-thirds of the corresponding values given in ‘Rations for Livestock’ (Evans, 1960).


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