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 utilization of spear grass (Heteropogon contortus). I. Factors limiting intake and utilization by cattle and sheep

1972 ◽  
Vol 23 (1) ◽  
pp. 35 ◽  
Author(s):  
BD Siebert ◽  
PM Kennedy
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Feed Consumption ◽  
Total Organic Matter ◽  
Mineral Supplement ◽  
Heteropogon Contortus ◽  
Total Intake ◽  
Digestible Organic Matter ◽  
Maintenance Requirements ◽  
Cattle And Sheep

The addition of 13.6% lucerne to a diet of spear grass increased the total intake of digestible organic matter of cattle by nearly 30%. Further additions (24.5 and 44.9%) increased the total organic matter intake, but decreased the spear grass intake. In cattle, the digestibility of the spear grass portion of the diet appeared to decrease as lucerne was added to the diet. Sheep consumed and digested spear grass poorly, although an addition of 14.4% legume increased both digestibility and intake. Further additions of legume slightly decreased the digestibility of the spear grass. The addition of urea alone did not influence digestion or feed intake by either cattle or sheep. When cattle were fed on spear grass, urea, and minerals, the quantity of organic matter digested was not significantly different from that with a diet of spear grass and 20% lucerne. The digestibility of the spear grass was not influenced by urea and minerals, whereas it decreased with the addition of lucerne. Increased feed consumption was maintained when various components of the mineral supplement were withdrawn, excepting nitrogen and sulphur. The energy derived from diets of spear grass and lucerne or spear grass and minerals appears to be above the maintenance requirements of cattle, but below those of sheep.

Herbage intake and production of Merino sheep grazing native and improved pastures at different stocking rates

1974 ◽  
Vol 14 (68) ◽  
pp. 307 ◽  
Author(s):  
JP Langlands ◽  
JE Bowles
Keyword(s):  
Organic Matter ◽  
Nutritive Value ◽  
Sheep Grazing ◽  
Merino Sheep ◽  
Wool Production ◽  
Herbage Intake ◽  
Digestible Organic Matter ◽  
Native Pastures ◽  
Stocking Rates ◽  
Improved Pasture

Estimates were made of the herbage intake, nutritive value of the diet, liveweight, wool production, efficiency of wool production and fleece characteristics of fine wool merino sheep grazing native pastures at stocking rates of 1.9, 3.7 and 5.6 sheep ha-1. The effects of increased stocking rates on these variables, and differences between improved and native pastures were examined by regression analysis. Organic matter digestibility declined with increasing stocking rate and was consistently less on native than on improved pasture as were the N content and the ratio, N : organic matter digestibility in the diet. Organic matter intake/sheep did not differ between pasture types or stocking rates, but digestible organic matter, digestible nitrogen and nitrogen intakes were less on native pasture, and paralleled seasonal changes in nutritive value, minimum values being recorded in late winter. Both wool production/sheep and liveweight were greater on improved pastures. Wool production ha-1 was 4 to 10 times greater on improved than on native pastures at stocking rates at which wool production/sheep were similar. Efficiency of wool production expressed as g wool/100 g digestible organic matter consumed was greater on improved pasture but when expressed/100 g nitrogen intake, sheep grazing native pasture were more efficient. Possible reasons are discussed. The maintenance requirements for energy appeared to be similar on both types of pasture. Fleeces produced on native pastures were generally lighter with shorter staple lengths, and appeared to be one spinning count finer than those produced on improved pasture. They were also superior in terms of softness and colour but were less uniform.

Some relationships between wool production, nitrogen intake and digestible organic matter intake

1976 ◽  
Vol 16 (78) ◽  
pp. 64
Author(s):  
GE Robards ◽  
DE Tribe ◽  
R Thomas
Keyword(s):  
Organic Matter ◽  
Crude Protein ◽  
Growth Response ◽  
Crude Protein Content ◽  
Short Term ◽  
Wool Production ◽  
Wool Growth ◽  
Dietary Nutrients ◽  
Nitrogen Intake ◽  
Digestible Organic Matter

Two experiments are described in which the wool production of Merino wethers receiving roughage rations of varying quantity and average crude protein content was examined. The results support a hypothesis that wool growth response to supplementation of low quality roughage is more closely related to the total digestible organic matter intake than to the total nitrogen intake. The second experiment demonstrates that in the short term the efficiency with which dietary nutrients are used for wool production depends upon the direction of liveweight change of the sheep.

Effect of divergent selection for weaning weight on liveweight and wool growth responses to feed intake in Merino ewes

1993 ◽  
Vol 33 (6) ◽  
pp. 699 ◽  
Author(s):  
RM Herd ◽  
VH Oddy ◽  
GJ Lee
Keyword(s):  
Organic Matter ◽  
Feed Intake ◽  
Divergent Selection ◽  
Growth Responses ◽  
Weaning Weight ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
Selection For ◽  
Response To Change

During a 6-week experiment, the feed requirements for maintenance of liveweight (LW) by adult Merino ewes were measured in 2 flocks selected over 32 years for divergent weaning weight. Also examined were the net efficiency of LW gain and wool growth in response to change in feed intake, and the ability to digest dietary organic matter. Ewes selected for high weaning weight (W+) were 31% heavier than those selected for low weaning weight (W-) at the start of the experiment. To maintain LW, W+ ewes ate 24% more digestible organic matter (DOM) per day than W- ewes. There were no differences (P>0.2) in the net efficiency of feed use for LW gain. The W+ ewes digested more (P<0.01) dietary organic matter, by 1.8 percentage units, than W- ewes and, consequently, required only 22% more dry feed to maintain their heavier LW. Ewes from the 2 flocks did not differ (P>0.4) in the amount of wool grown, and as W+ ewes were larger, they produced less (P<0.01) wool per kg LW for the same DOM intake.

Wool growth of pregnant and lactating Merino ewes

1985 ◽  
Vol 105 (3) ◽  
pp. 613-622 ◽  
Author(s):  
V. H. Oddy
Keyword(s):  
Organic Matter ◽  
Fibre Diameter ◽  
Wool Fibre ◽  
Total Plasma ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
Pregnancy And Lactation ◽  
The Difference ◽  
The Relationship ◽  
Growth Deficit

SUMMARYThe wool production of pregnant, lactating and non-pregnant, non-lactating (dry) Merino ewes eating one of three diets: chaffed oaten hay (OH), chaffed lucerne hay (LH), and a 50/50 (w/w) mixture of OH and LH, was determined. Measurements were made for 2 months prior to mating, during pregnancy and for 3 months after lambing, and for the dry ewes over the same period.Production of clean wool (Y, g/day) by dry ewes was linearly related to digestible organic matter intake (X, g/day):Y = 0·0301 X - 3·34, r = 0·97.Clean wool growth was significantly less (P < 0·01) than dry ewes in the 4th and 5th month of pregnancy and throughout lactation. During pregnancy the total deficit in clean wool growth (calculated as the difference between observed wool growth and that expected on the basis of the relationship between feed intake and clean wool growth of dry ewes) was 456 g for ewes bearing a single lamb and 578 g for those bearing twins, with no difference between diets. In lactation the total clean wool growth deficit increased as milk production increased, and for every litre of milk produced there was a deficit of 12 g clean wool.Wool fibre diameter was reduced during the 1st month of lactation. There was no consistent effect of pregnancy or lactation on the number of wool follicles per mm2, the ratio of primary plus secondary to primary wool follicles, or on the thickness of skin on the midside.Digestibility of dietary organic matter (DOM) was reduced during the last 3 months of pregnancy, and the first 2 months of lactation. However, this was insufficient to account for the magnitude of the decrease in wool growth seen during pregnancy and lactation.Wool sulphur content increased during pregnancy (P < 0·001), but not during lactation. The relationship between total plasma cyst(e)ine concentration and DOM intake during pregnancy was similar to that in dry ewes, but during lactation total plasma cyst(e)ine concentration was less than expected. It was calculated that during pregnancy the amount of sulphur saved through reduced wool growth was greater than that deposited in the conceptus, and during lactation the amount of sulphur saved in reduced wool growth matched that excreted as milk.These results are discussed in relation to control of wool growth during pregnancy and lactation.

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.

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.

An assessment of the quality of forage from its cell-wall content and amount of cell wall digested

1972 ◽  
Vol 78 (3) ◽  
pp. 355-362 ◽  
Author(s):  
K. W. Moir
Keyword(s):  
Cell Wall ◽  
Organic Matter ◽  
Ammonium Oxalate ◽  
Physical Structure ◽  
Tropical Species ◽  
Average Amount ◽  
Lignin Concentration ◽  
Digestible Organic Matter ◽  
The Difference

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.

A Comparative Study of Sheep Grazing a Semi-Arid Saltbush Pasture in Two Condition Classes.

1986 ◽  
Vol 8 (1) ◽  
pp. 46 ◽  
Author(s):  
RD Graetz
Keyword(s):  
Nutritional Value ◽  
Body Weight Gain ◽  
Landsat Imagery ◽  
Stocking Rate ◽  
Sheep Grazing ◽  
Wool Production ◽  
Broken Hill ◽  
Wool Growth ◽  
Stocking Rates

Measurements were made of the wool growth, body weight gain and diet of sheep grazing a saltbush pasture near Broken Hill, N.S.W. The experiment utilized a fenceline contrast in saltbush (Atriplex vesrcarra) density that was visible on Landsat imagery. It ran for five years (1976-1981) with a design of two pasture types by two stocking rates. Fleece weights varied from 3.9-6.0 kg/head and wool production from 0.6-2.9 kg/ha. Neither wool production per head nor bodyweight were substantially affected by stocking rate or pasture type. The composition and quality of the diets selected by sheep on both pastures were identical and of high nutritional value indicating their capability to accommodate differences in pasture composition. Pasture quality was not limiting between stocking rates or determined by the abundance of saltbush. Changes in pasture composition resulting from grazing and exclosure were small and of no significance.

Effects of shelter, exposure and level of feeding over winter on the productivity of Welsh Mountain ewes and lambs

1973 ◽  
Vol 17 (1) ◽  
pp. 21-32 ◽  
Author(s):  
W. I. Robinson ◽  
W. Brown ◽  
I. A. M. Lucas
Keyword(s):  
Weight Loss ◽  
Body Weight ◽  
Organic Matter ◽  
Live Weight ◽  
Outdoor Exposure ◽  
Wool Growth ◽  
Digestible Organic Matter ◽  
Maintain Body Weight ◽  
Fourth Experiment ◽  
Different Levels

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.

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