scholarly journals The intake, digestion and protein degradation of grazed herbage by early-weaned lambs

1992 ◽  
Vol 68 (2) ◽  
pp. 349-364 ◽  
Author(s):  
G. J. Cruickshank ◽  
D. P. Poppi ◽  
A. R. Sykes

Sixty-four intact lambs and twenty-four lambs fitted with a duodenal cannula were weaned at 6 weeks of age and grazed pure species swards of either lucerne (Medicago sativa), white clover (Trifolium repens), ryegrass (Lolium perenne) or prairie grass (Bromus catharticus) for 6 weeks. Intake and duodenal digesta flow were estimated when lambs were 8 and 12 weeks of age. Lambs grazing the two legume species grew at a similar rate, as did lambs grazing the two grass species. Legumes promoted a 38% higher growth rate than grasses. The higher growth rate of lambs grazing legumes was associated with a 36% higher digestible organic matter intake (DOMI; 29.5 and 21.7 g/kg body-weight per d for legume and grass respectively) and a 33% higher duodenal non-ammonia-nitrogen (NAN) flow (1.22 and 0.92 g/kg body-weight per d respectively). There was no species difference in the site of organic matter digestion; on average 0.56 of DOMI was apparently digested in the rumen and 0.77 of DOMI was truly digested in the rumen. There was no difference in duodenal NAN flow, relative to DOMI (average, 43 g/kg) or to organic matter apparently digested in the rumen (80 g/kg). Similarly, there was no difference in microbial N flow relative to duodenal NAN (0.50 g/g) and organic matter apparently (41 g/kg) or truly (29 g/kg) digested in the rumen. It was concluded that the higher growth rates achieved by lambs grazing legumes were due to higher intakes which increased the total quantity of nutrients supplied despite more protein being lost in the rumen of lambs consuming legumes.

2003 ◽  
Vol 76 (2) ◽  
pp. 319-326
Author(s):  
J. van E. Nolte ◽  
A.V. Ferreirat ◽  
H.H. Köster

AbstractA 5 ✕ 5 Latin square was conducted with ruminally and duodenally cannulated Dohne Merino wethers consuming wheat straw to determine the effect of different rumen degradable protein (RDP) levels on forage intake, fermentation characteristics, nutrient flow and digestion. The wethers had ad libitum access to water and wheat straw (32 g crude protein (CP) per kg dry matter (DM); 742 g neutral-detergent fibre (NDF) per kg DM) that was offered twice daily, immediately after intraruminal infusion of the supplements at 07:00 and 19:00 h. The supplemental RDP (calcium caseinate; 900 g CP per kg DM) levels were: 0, 40, 80, 120 and 160 g/day. Each period consisted of 14 days of adaptation and 6 days of sampling. Forage and total organic matter (OM) intakes increased in a linear manner (P < 0•01) with increasing supplemental RDP levels. Digestible organic matter intake (DOMI) displayed a quadratic increase with elevated amounts of RDP (P < 0•01). The effects of treatments on rumen and total tract digestion, as well as fluid dilution rate were minimal. Microbial nitrogen (MN) flow to the duodenum and microbial efficiency increased quadratically (P < 0•04) with increased RDP supplementation. Rumen ammonia nitrogen (NH3-N) concentrations increased linearly (P < 0•01) and total volatile fatty acids (VFA) tended to increase linearly (P = 0•07). In conclusion, RDP supplementation to Dohne Merino wethers consuming wheat straw generally enhanced rumen fermentation and forage intake. A total RDP intake (sources: calcium caseinate and wheat straw) of 3•30 g/kg M0•75 or 0•12 of DOM maximized DOMI.


1975 ◽  
Vol 20 (2) ◽  
pp. 233-241 ◽  
Author(s):  
J. M. Walsingham ◽  
R. V. Large ◽  
J. E. Newton

SummaryThe value of E, defined as the weight of carcass produced per 100 units of digestible organic matter (DOM) consumed, was used to assess the biological efficiency of meat production in housed sheep. The effect on E of weaning lambs at 4, 6, 8, 10, 12, 14 and 16 weeks post partum was studied for a number of different breed crosses. The age at which lambs were weaned was found to have little effect on the growth rate of lambs and no significant effect on the biological efficiency with which sheep produce meat.


1973 ◽  
Vol 17 (1) ◽  
pp. 21-32 ◽  
Author(s):  
W. I. Robinson ◽  
W. Brown ◽  
I. A. M. Lucas

SUMMARYPregnant Welsh Mountain ewes were kept over winter on a hill. All were penned individually, either in a shed or out of doors. In Experiments 1 and 2 different levels of digestible organic matter (DOM) were given in each environment and in Experiment 3 only a single level was offered. In Experiment 2 all ewes were grazed together after lambing; in Experiment 3 some from each treatment were moved to a shed after lambing and their milk yields recorded between 10 and 15 days later.In a fourth experiment on low land, pregnant ewes were either housed or kept in an exposed or a sheltered paddock. All were grazed together after lambing.The results indicated that the requirement of indoors penned sheep to maintain body weight and produce a single lamb is 9·5 g DOM/kg live weight per 24 hr at 16 weeks pre-partum, rising to 15·0 g DOM/kg live weight per 24 hr at 1 week pre-partum. A 10% weight loss during pregnancy would be expected in ewes receiving 75 to 80 % of these requirements. Low intakes during pregnancy reduced wool growth and lamb birth weights.Outdoor exposure reduced pre-partum ewe weight by about 1·5 kg, and so was equivalent to a 10% reduction in daily DOM intake. The magnitude of this effect was not changed significantly by level of feeding. Exposure did not affect wool growth and its influence on lamb birth weight and growth was variable.


1967 ◽  
Vol 7 (26) ◽  
pp. 199 ◽  
Author(s):  
ME Bourke

The experiment investigated factors associated with differences in growth rate from birth to seven weeks, by two crossbreeds of lamb. The Dorset Horn x Border Leicester-Merino grew at 0.18 kg per day, and the Dorset Horn x Merino grew at 0.14 kg per day (P<0.001) although both crosses consumed the same digestible organic matter intake. Thus the second cross was significantly more efficient (P<0.05) than the first cross. Two levels of milk were also fed to both crosses and, although the high level improved growth rate (P <0.001), it did not effect the efficiency of conversion of food to animal tissue.


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.


1982 ◽  
Vol 35 (1) ◽  
pp. 157-161
Author(s):  
M. Hadjipanayiotou

ABSTRACTPoultry litter collected from a commercial broiler house, bedded with wood shavings, was used. The material was screened and ground before it was ensiled either alone or with other agricultural by-products, namely chopped barley straw, a mixture of weeds and grapefruit peels. The digestible organic matter in the dry matter value in vitro (0·39) for litter was comparable with that for straw and weeds. Of the total nitrogen (36·3 g/kg dry matter), 0·19 was ammonia-nitrogen and 0·77 protein-nitrogen. Digestible energy and crude fibre in the litter were 7·19 MJ and 334 g/kg dry matter, respectively. Addition of poultry litter at ensiling resulted in significant increases in nitrogen and ash content of the original mixtures. Inclusion of sodium hydroxide in fermented and non-fermented mixtures elevated digestible organic matter in the dry matter values in vitro by 0·19 and 0·13, respectively; the crude fibre concentration was lowered. All initial mixtures were free of lactic acid and were positive for the pathogen Proteus when tested. Unlike crude fibre, fatty acid and free ammonia, which were increased after fermentation, digestible organic matter in the dry matter and pH values were decreased. Ensiling killed the pathogen Proteus in the majority of the silages tested. The silages had a pleasant aroma and colour, and were consumed by Chios 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.


Author(s):  
D I Givens ◽  
Jeannie M Everington

Despite its importance, relatively few measurements have been made of the metabolisable energy (ME) content of fresh herbage. Changes in the nutritive value of spring herbage are commonly described in terms of its digestible organic matter content (DOMD) either measured in vitro or predicted from a fibre fraction. ME is normally assumed to be directly proportional to DOMD.Energetic studies of herbage such as those of Armstrong (1964) and Beever et al (1985) have been restricted to pure species and one location. The purpose of the present experiment was to examine changes in DOMD and energy values with increasing maturity in vivo using sheep in commercial swards over several years.


1979 ◽  
Vol 30 (3) ◽  
pp. 533 ◽  
Author(s):  
RH Weston

The voluntary feed consumption (VFC) and body weight gain of lambs initially weighing 22 kg were measured when pelleted diets based on ground wheat grain and varying in content of ground straw were offered. VFC increased progressively as the straw content of the diet was increased from 2% through 8% to 14%. Lambs fed on the diets with 8 and 14% straw performed similarly, whereas those with 2% straw had lower rates of body weight gain (– 11%) and intakes of digestible organic matter (– 4%). Increase in straw content from 2 to 14% was accompanied by a decrease in diet digestibility and increases in (i) the rates of flow from the rumen of digesta, sodium and potassium, (ii) the pH of ruminal contents, and (iii) the time spent ruminating. Lambs initially weighing 37 kg were offered 'roughage-free' concentrate diets based on wheat in which the wheat was presented either as whole grain or in ground and pelleted form. With whole grain, values for VFC, digestible organic matter intake and body weight gain were respectively 17, 17 and 29% higher than with ground grain. The feeding of whole grain instead of ground grain increased the time spent daily in ruminating from 0.3 to 2.2 h. It was concluded that the roughage requirement of the ruminant lamb fed on concentrate diets based on wheat was higher when the wheat was in ground form than when whole grain was used. The requirement with ground wheat diets was tentatively assessed as in the range of 2–8 g ground straw per 100 g diet. Lambs were slow in adapting to a chopped roughage diet following prolonged feeding with wheat-based diets. VFC data suggested that the slow adaptation was associated with changes in rumen function. _______________ *Part VIII, Aust. J. Agric. Res., 25, 349 (1974).


1976 ◽  
Vol 16 (80) ◽  
pp. 315 ◽  
Author(s):  
KD Atkins ◽  
GE Robards

A handfeeding experiment was conducted with weaner ewe lambs from two Merino flocks. One flock had been selected for high net reproductive rate, growth rate and wool production (fertility flock) ; the other flock was a randomly selected control flock (random flock). Single and twin born lambs from each flock were used in the experiment. Lambs were randomized into four treatment groups and offered the diet either ad libitum or at one of three levels estimated to restrict growth rate to 50, 100 and 150 g day-1. At each level of feeding, fertility flock lambs grew faster and were more efficient in converting feed to liveweight gain. Over the whole experiment the feed conversion efficiencies in g gain per kg digestible organic matter intake per day were 218 and 185 (P < 0.05) for the fertility and random flocks respectively. There were no significant differences in growth rate or efficiency of conversion of feed to liveweight gain between single-born and twin-born lambs. Random flock lambs had a significantly higher wool growth rate and were more efficient converters of feed to wool than fertility flock lambs. Gross efficiencies were 10.8 and 9.1 g clean wool per kg digestible organic matter intake per day (P < 0.05) for random and fertility flock lambs respectively. Single-born lambs grew significantly more wool than twin-born lambs but there was no significant difference between birth types in the efficiency of conversion of feed to wool.


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