Effect of environment on the maintenance requirements of Merino wethers

1963 ◽  
Vol 14 (2) ◽  
pp. 272 ◽  
Author(s):  
LJ Lambourne ◽  
TF Reardon
Keyword(s):  
Small Groups ◽  
Nitrogen Concentration ◽  
Daily Intake ◽  
Cost Of Locomotion ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Maintenance Requirements ◽  
The Relationship ◽  
Energy Cost Of Locomotion ◽  
Stimulation Of

Small groups of Merino wethers were maintained at virtually constant liveweight in four "environments" and their maintenance feed requirements estimated from the relationship between their fluctuations in liveweight over 14-day periods and their feed intakes, measured directly or estimated by chromium oxide dilution and faecal nitrogen concentration. When adult wethers of equal size but a varying degree of fatness were fed on fresh pasture herbage in metabolism pens, liveweights of 26, 32, and 46 kg could be maintained on a daily intake of approximately 200, 300, and 420 g digestible organic matter (D.O.M.) respectively. When the metabolism pens were placed outdoors in winter the maintenance requirements rose, the rise appearing to be greatest for the thin sheep. When wethers were allowed to graze for about 1½ , 2½, and 4 hr in abundant pasture, liveweights of 26, 33, and 46 kg were maintained on intakes of approximately 420, 480, and 490 g D.O.M. respectively. When the same wethers were allowed to graze freely and weight was controlled by the scarcity or abundance of the pasturage, the same liveweights were maintained on intakes of about 750, 780, and 560 g D.O.M. respectively. The rise in maintenance requirements on short pasture seems too great to be explained by the increased energy cost of locomotion and grazing. The possibility of an endocrine stimulation of metabolic rate is pointed out.

The use of chromium oxide and faecal nitrogen concentration to estimate the pasture intake of Merino wethers

1963 ◽  
Vol 14 (2) ◽  
pp. 257 ◽  
Author(s):  
LJ Lambourne ◽  
TF Reardon
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Nitrogen Concentration ◽  
Linear Equations ◽  
Large Measure ◽  
Feed Digestibility ◽  
Wide Range ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Maintenance Requirements

Statistical analysis of the results of digestion trials on a wide range of fresh pasture herbages shows that their digestibility might be estimated as the intake factor or feed faeces ratio (Y) from the equation: YO.M. = (2.04 – 0.24XN ± 0.186X2N) ± 0.53 where YO.M. is the intake factor for organic matter, and XN is the percentage of nitrogen in faecal organic matter. The results were subdivided arbitrarily into "summer" (September–April) and "winter" (May–August) periods, and these proved to yield significantly different linear equations. The summer regression yielded higher intake factors (corresponding to 2–3% higher digestibility) for a given value of faecal nitrogen percentage. This subdivision reduced the standard deviation from regression only slightly, to about 0.50, which amounts to ± 17% for pasture of 75% digestibility. These equations give considerably lower values of digestibility for a given nitrogen concentration than regressions hitherto published. The present pooled equation, based on short leafy herbage, probably gives sounder estimates for grazing sheep than do the existing equations derived from trials with more mature herbages. When sheep with a wide range in body weight were all fed a maintenance ration, it was found that feed digestibility was not detectably reduced at high levels of feeding. The undoubtedly higher feed intake of grazing than of pen-fed animals, due in large measure to their higher maintenance requirements, therefore may not cause the reduction in digestive efficiency, and thus the bias in estimates of feed intake, that has been supposed. On the basis of the pooled regression, which is felt to be preferable to a subjectively selected "seasonal" equation, estimates of the intake of digestible organic matter (D.O.M.) by sheep in metabolism pens fed on fresh pasture herbage averaged 97 ± 22% of the true figures, or ± 80 g D.O.M.

The use of faecal nitrogen as an index for estimating the consumption of herbage by grazing animals

1963 ◽  
Vol 61 (1) ◽  
pp. 33-43 ◽  
Author(s):  
G. W. Arnold ◽  
M. L. Dudzinski
Keyword(s):  
Organic Matter ◽  
Nitrogen Concentration ◽  
Linear Equations ◽  
Slope Position ◽  
Seasonal Differences ◽  
Faecal Nitrogen ◽  
Independent Variable ◽  
Regression Relations ◽  
The Relationship ◽  
Better Than

Data from thirty-five digestibility trials with sheep in metabolism cages were used to investigate statistically the relationships between organic matter intake (I), faecal organic matter output (F), and the nitrogen concentration in faecal organic matter (N).The data fell easily into groups due to botanical or seasonal differences in the feed. These groups of data were homogeneous and provided highly significant linear equations of the forms I = bF + cFN and I = a + cFN. When compared these groups of data sometimes showed differences in slope, position or both. A quadratic expressionI = bF + cFN + dFN2was found to accommodate a majority of the data but to be less precise than I = a + cFN.A further expression incorporating N as an independent variable was also examined,I = a + cFN2 + eN.This expression, although far from being universally adequate, proved to be generally better than existing formulae. When applied to the data of Greenhalgh et. al. (1960), it substantially reduced heterogeneity between data for spring and data for summer pastures.Causes of variation in the relationship between organic-matter intake and nitrogen in faeces, and some of the hazards of extrapolation from empirical regression relations, are discussed.

Estimates of the energy required for maintenance by adult sheep 2. Grazing sheep

1963 ◽  
Vol 5 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald ◽  
G. W. Reid
Keyword(s):  
Organic Matter ◽  
Energy Cost ◽  
Functional Relationship ◽  
Adult Sheep ◽  
Maintenance Requirement ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Grazing Period ◽  
The Mean ◽  
Maintenance Requirements

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.

The relationship between apparent retention time in the rumen, voluntary intake, and apparent digestibility of legume and grass diets in sheep

1973 ◽  
Vol 24 (6) ◽  
pp. 889 ◽  
Author(s):  
RF Thornton ◽  
DJ Minson
Keyword(s):  
Organic Matter ◽  
Retention Time ◽  
Daily Intake ◽  
Organic Matter Content ◽  
Matter Content ◽  
Apparent Digestibility ◽  
Jaw Movements ◽  
Digestible Organic Matter ◽  
Voluntary Intake ◽  
The Relationship

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.

Stimulation of wool growth by thyroxine implantation. II. Feed intake of grazing Merino wethers treated repeatedly with thyroxine.

1964 ◽  
Vol 15 (4) ◽  
pp. 676 ◽  
Author(s):  
LJ Lambourne
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Sheep Grazing ◽  
Wool Production ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
The Difference ◽  
Maintenance Requirements ◽  
Substantial Rise ◽  
Stimulation Of

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.

The effect of herbage allowance on herbage intake and performance of lambs grazing perennial ryegrass and red clover swards

1976 ◽  
Vol 86 (2) ◽  
pp. 355-365 ◽  
Author(s):  
M. J. Gibb ◽  
T. T. Treacher
Keyword(s):  
Growth Rate ◽  
Organic Matter ◽  
Perennial Ryegrass ◽  
Nitrogen Fertilizer ◽  
Daily Intake ◽  
Live Weight ◽  
Red Clover ◽  
Asymptotic Curves ◽  
Digestible Organic Matter ◽  
The Relationship

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.

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
Keyword(s):  
Organic Matter ◽  
Nutritional Quality ◽  
Daily Intake ◽  
Grass Species ◽  
Digestible Organic Matter ◽  
Voluntary Intake ◽  
Alfalfa Varieties ◽  
The Relationship ◽  
Time Of Harvest

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.

The indirect estimation of the digestibility of pasture herbage III. Regressions of digestibility on faecal nitrogen concentration: effects of species and individuality of animal and of the method of determining digestibility upon the relationships

1963 ◽  
Vol 61 (2) ◽  
pp. 221-226 ◽  
Author(s):  
J. P. Langlands ◽  
J. L. Corbett ◽  
I. McDonald
Keyword(s):  
Organic Matter ◽  
Dry Matter ◽  
Nitrogen Concentration ◽  
Regression Coefficients ◽  
Regression Equations ◽  
Concentration Effects ◽  
Animal Data ◽  
Faecal Nitrogen ◽  
Relationship Of ◽  
The Relationship

1. A 36-day continuous digestibility trial with three steers and three sheep fed fresh pasture herbage was carried out during May and June, 1960. For all animals the digestibilities of herbage organic matter (O.m.) were estimated both by collection of faeces and by administering standard quantities of chromium sesquioxide (Cr203) twice daily and determining concentrations of Cr203 in faeces. In a further 36-day trial during August and September 1960, three steers and three cows were used; with the steers, digestibilities were estimated by both methods but with the cows by the Cr203 method only.2. Regression equations were obtained relating O.m. digestibility to the percentage of nitrogen (N) in faecal O.m. When digestibilities were estimated by the same method the same regression coefficients could be fitted to the data from each of the steers and sheep in the spring trial. A similar result was found with the data from each of the steers and cows in the summer trial.3. In each equation different constant terms were required for each animal, which differed significantly between individuals but not between species or class of animal. Data obtained from an examination of the relationship of g. N excreted per 100 g. feed dry matter to g. N intake per 100 g. feed dry matter indicated that differences between the constant terms could be linked with variations between animals in the excretion of metabolic faecal N.

The indirect estimation of the digestibility of pasture herbage I. Nitrogen and chromogen as faecal index substances

1960 ◽  
Vol 55 (3) ◽  
pp. 371-376 ◽  
Author(s):  
J. F. D. Greenhalgh ◽  
J. L. Corbett
Keyword(s):  
Organic Matter ◽  
Nitrogen Concentration ◽  
Regression Equation ◽  
Seasonal Differences ◽  
Indirect Estimation ◽  
Faecal Nitrogen ◽  
Standard Deviations ◽  
The Difference ◽  
The Relationship ◽  
Single Regression

1. In seventeen digestibility trials carried out between May and November, 1957, groups of three steers were fed on fresh herbage, cut mainly from mixed swards. Herbage digestibility and the concentrations in faeces of the index substances nitrogen and chromogen were measured over periods of 5 days. Organic matter digestibility ranged from 61·2 to 78·9%.2. The relationship between herbage digestibility and faecal nitrogen concentration could not be described satisfactorily by a single regression equation for all trials, and separate equations were calculated for (a) first-growth herbage and (b) aftermath (second and third growths). For a given faecal nitrogen concentration herbage digestibility was about five units higher for first-growth than for aftermath herbage.3. For the faecalchromogen-digestibilityrelationship the difference between growths was even greater and, again, two equations were required. In most trials the quantity of chromogen excreted was apparently greater than the quantity consumed.4. The ‘seasonal’ differences in faecal index relationships were caused by the fact that later growths of herbage contained considerably greater concentrations of nitrogen and chromogen than did firstgrowth herbage of the same digestibility. There was also some evidence that the relationships may be affected by the application of nitrogenous fertilizers to the sward.5. In order to avoid biases in the indirect estimation of herbage digestibility it appears important to use different regressions for different growths. Although such regressions would be restricted in their application they are likely to be more precise than general equations. In these trials both nitrogen and chromogen regressions had low residual standard deviations of ± 1·5 units of digestibility.

Energy Cost and Stride Duration Variability at Preferred Transition Gait Speed Between Walking and Running

1996 ◽  
Vol 21 (6) ◽  
pp. 471-480 ◽  
Author(s):  
Jeanick Brisswalter ◽  
Denis Mottet
Keyword(s):  
Key Words ◽  
Energy Cost ◽  
Gait Speed ◽  
Alternative Hypothesis ◽  
Transition Speed ◽  
Treadmill Speed ◽  
Cost Of Locomotion ◽  
Stride Duration ◽  
The Relationship ◽  
Energy Cost Of Locomotion

The aim of this study was to explore the relationship between energy cost of locomotion and stride duration variability in the region of the walk-run transition speed. Ten subjects participated in this experiment during four treadmill sessions. The first session was used to habituate subjects to treadmill walking or running. During the second session the treadmill speed was increased from 6 km∙h−1 to 10 km∙h−1 in steps of 0.2 km∙h−1 to determine the freely chosen transition speed between walking and running (ST). The last two sessions consisted of five walks or five runs conducted at five intensities selected to represent respectively ST−1 km∙h−1; ST−0.5 km∙h−1; ST; ST + 0.5 km∙h−1; and ST + 1 km∙h−1. Exhaled gases were collected during the last two sessions, and stride duration was continuously recorded. The results indicated a significant increase in stride duration variability before ST for the freely chosen gait condition only. These findings point to an alternative hypothesis to that classically proposed to describe a transition as an energy saving mechanism. Key words: variability, locomotion, energy cost, transition speed

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