Studies in the wool production of grazing sheep. 4. Variation between sheep in intake, wool production, and efficiency

1966 ◽  
Vol 6 (20) ◽  
pp. 96 ◽  
Author(s):  
WR McManus ◽  
GW Arnold ◽  
ML Dudzinski
Keyword(s):  
Organic Matter ◽  
Wool Production ◽  
Digestible Organic Matter ◽  
Grazing Sheep ◽  
Stocking Rates

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.

A comparison of the forage value for sheep of buckwheat and sorghum stubbles grown on the Southern Tablelands of New South Wales

1979 ◽  
Vol 19 (98) ◽  
pp. 297 ◽  
Author(s):  
JG Mulholland ◽  
JB Coombe
Keyword(s):  
Organic Matter ◽  
New South ◽  
Experimental Period ◽  
Stocking Rate ◽  
Wool Production ◽  
Weight Losses ◽  
South Wales ◽  
Digestible Organic Matter ◽  
Forage Value ◽  
Stocking Rates

Two grazing experiments were conducted to evaluate buckwheat and sorghum stubbles as forage for sheep. The stubbles were stocked by young crossbred wethers at 10 and 20 ha-1 for 55 days on the buckwheat and 81 days on the sorghum. Measurements were made at regular intervals of the availability and composition of plant material, diet selection, the intake of digestible organic matter (DOM) and liveweight change, while wool production was measured over each experimental period. More than one-third of the sheep grazing buckwheat stubble were affected by fagopyrism (buckwheat poisoning) and this probably reduced both liveweight gain and wool production. Buckwheat residues had a similar nitrogen content to sorghum (1 .0% vs 0.87%), but a lower organic matter digestibility (43.7% vs 57.1%). Mature buckwheat plants were not eaten readily. Mean liveweights of sheep on buckwheat stubble declined throughout the experimental period and overall changes were -3.8 and -7.0 kg for the low and high stocking rates, respectively. Corresponding values for sheep on sorghum stubble were 0.3 and -4.6 kg, although weight losses at the higher stocking rate did not occur until after 40 days grazing. For the same length of grazing as the buckwheat (55 days) the liveweight changes for sorghum were 0.2 and -1.2 kg, respectively. Wool growth rate was low for both stubbles but was more than 60% higher for sheep on the sorghum. Values for each stocking rate were 3.86 and 2.67 (g clean dry wool day-1) for the buckwheat, and 5.39 and 4.33 for the sorghum. It was concluded that sorghum stubble is a useful source of grazing for sheep on the Southern Tablelands but buckwheat stubble, because of its low acceptability, poor nutritional value and the risk of fagopyrism, is of very limited value.

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.

Comparing estimates of herbage digestibility from faecal nitrogen and in vitro determinations

1980 ◽  
Vol 31 (1) ◽  
pp. 57-62
Author(s):  
H. A. Birrell
Keyword(s):  
Organic Matter ◽  
Digestible Organic Matter ◽  
Faecal Nitrogen ◽  
Feeding Trials ◽  
Grazing Sheep ◽  
Organic Matter Digestibility ◽  
Image Position ◽  
Stocking Rates

ABSTRACTIn a grazing experiment, the organic matter digestibility of herbage selected by sheep grazing at two stocking rates was determined at monthly intervals over a 9-month period by (i) the in vitro determination of organic matter digestibility of the material collected from sheep fitted with an oesophageal fistula, and (ii) derivation from the prediction of digestible organic matter intake with a faecal nitrogen regression. A comparison of the two techniques confirms the view of other workers that faecal nitrogen indices based on pen feeding trials of green herbage are unreliable for predicting digestibility of green herbage in the field. The bias which is produced by faecal nitrogen regression appears to be associated with the time spent grazing by the animal each day. Relating organic matter digestibility directly to nitrogen content of faeces of grazing sheep (N, g nitrogen/100 g faecal organic matter) and their grazing time (T,h) yielded the following equation:The expression has standard errors (±2·6) similar to those involved in an in vitro determination. It provides a simple technique for estimating digestibility of herbage eaten by grazing sheep, but this may only be applicable to the particular sward conditions.Field estimates of digestibility over summer and autumn by this equation were found to be similar to estimates by a faecal nitrogen expression established from hand feeding sheep with dry summer herbage.

The intake and production of lactating Merino ewes and their lambs grazed at different stocking rates

1977 ◽  
Vol 28 (1) ◽  
pp. 133 ◽  
Author(s):  
JP Langlands
Keyword(s):  
Organic Matter ◽  
Milk Production ◽  
Metabolizable Energy ◽  
Milk Consumption ◽  
Total Organic Matter ◽  
Stocking Rate ◽  
Wool Production ◽  
Maintenance Requirement ◽  
Stocking Rates

Grass and milk consumption and liveweight changes of lambs grazed at stocking rates ranging from 9 to 35 sheep/ha were measured during a 105 day lactation. Grass consumption and wool production of their mothers and of similar ewes without lambs were also determined. The forage and total organic matter intakes of the lamb increased with time while milk consumption declined; all three variables were negatively correlated with stocking rate. The intake of the ewe and its liveweight gain were not sensitive to increasing stocking rate, but wool production declined at higher stocking rates. The maintenance requirement of the ewes was estimated to be 218 kJ metabolizable energy/kg liveweight, and the efficiency with which metabolizable energy was utilized for milk production was 66%. Lactation increased the intake of the ewe but reduced its wool production.

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.

Studies in the wool production of grazing sheep. 3. Changes in efficiency of production

1965 ◽  
Vol 5 (19) ◽  
pp. 396 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
ML Dudzinski
Keyword(s):  
Activity Index ◽  
Seasonal Pattern ◽  
Maximum Effect ◽  
Wool Production ◽  
Maximum Value ◽  
Cent Increase ◽  
The Mean ◽  
Grazing Sheep ◽  
Maintenance Requirements ◽  
Stocking Rates

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.

Stocking intensity and pastoral production: III. Wool production, fleece characteristics, and the utilization of nutrients for maintenance and wool growth by Merino sheep grazed at different stocking rates

1973 ◽  
Vol 81 (2) ◽  
pp. 211-218 ◽  
Author(s):  
J. P. Langlands ◽  
I. L. Bennett
Keyword(s):  
Live Weight ◽  
Early Spring ◽  
Metabolizable Energy ◽  
Late Winter ◽  
Stocking Rate ◽  
Wool Production ◽  
Digestible Organic Matter ◽  
Unit Increase ◽  
Rate Of Decline ◽  
Stocking Rates

SummaryWool production and wool characteristics are reported for a 5-year period in which sheep grazed Phalaris tuberosa–Trifolium repens pastures at stocking rates ranging from 2·5 to 37·1 sheep/ha. The utilization of nutrients for maintenance and wool production were calculated over shorter periods.Maximum wool production/ha was always recorded at the highest stocking rate attained. The highest annual maximum was 111 kg clean wool/ha in 1963–4. The decline in wool production/sheep/unit increase in stocking rate was greatest during winter and the amplitude of the seasonal rhythm in wool production increased with stocking rate.At high stocking rates wool count increased, staple length and character declined, colour and handle improved, soundness tended to decline and fibre entanglement (cotting) to increase particularly during drought. Live-weight gain/sheep also declined with stocking rate, the rate of decline being greatest during drought. Maximum live-weight change/ha was attained at a lower stocking rate than maximum wool production/ha.The maintenance requirement of grazing sheep was estimated to be 58·3 kcal metabolizable energy/day/kg live weight and did not vary consistently with stocking rate. The value was 79% greater than the requirements for penned sheep estimated from fasting heat production.Efficiency of wool production was defined as wool grown/100 g digestible organic matter intake (ED) and as wool grown/100 g nitrogen intake (EN). EN declined linearly with increasing stocking rate but the intercepts differed between months, and were least in late winter and early spring. En declined with stocking rate in winter and increased during summer. At low stocking rates, ED showed some variation throughout the year but this was much greater at high stocking rates.

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
Keyword(s):  
Organic Matter ◽  
Nutritional Value ◽  
Late Summer ◽  
Index Method ◽  
Nitrogen Intake ◽  
Digestible Organic Matter ◽  
The Mean ◽  
Grazing Sheep ◽  
Summer Minimum ◽  
Maintenance Requirements

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.

Studies in the wool production of grazing sheep. 5. Observations on teeth wear and carry over effects

1966 ◽  
Vol 6 (20) ◽  
pp. 101 ◽  
Author(s):  
GW Arnold ◽  
WR McManus ◽  
IG Bush
Keyword(s):  
Live Weight ◽  
Subterranean Clover ◽  
Stocking Rate ◽  
Wool Production ◽  
Grazing Sheep ◽  
Carry Over ◽  
Stocking Rates

Merino wethers were grazed for four years on Phalaris-subterranean clover pastures at four stocking rates. Measurements over two years showed that wear of incisor teeth increased substantially with stocking rate. This wear was closely associated with intake of silica by the sheep. After the experiment marked carry-over effects in wool production and live weight were observed in adult wethers. Significantly more wool was produced by sheep previously grazing at high stocking rates. Possible reasons for this effect are discussed.

Factors limiting the intake of feed by sheep. V. Feed intake and the productive performance of the ruminant lamb in relation to the quantity of crude protein digested in the intestines

1971 ◽  
Vol 22 (2) ◽  
pp. 307 ◽  
Author(s):  
RH Weston
Keyword(s):  
Organic Matter ◽  
Crude Protein ◽  
Dry Matter ◽  
Tritiated Water ◽  
Essential Amino Acids ◽  
Feed Consumption ◽  
Wool Production ◽  
Volatile Fatty Acid Concentration ◽  
Digestible Organic Matter ◽  
Peripheral Blood Plasma

The voluntary feed consumption (VFC), liveweight increase, and wool growth of lambs, initially 9-10 weeks old and weighing 22 kg, were measured over 6 weeks when pelleted diets of differing protein content were offered. The crude protein contents of the diets, on a dry matter basis, were 11.7% (LP diet), 15.8% (MP diet), and 19.1 % (HP diet). The digestion of the HP and LP diets was studied, with use of markers, in similar lambs prepared with stomach fistulae. VFC, expressed as grams dry matter/day/kg body weight0.75, was 82 (SE�3) with the LP diet, 94�3 with the MP diet, and 97�4 with the HP diet. The dietary crude protein intakes were 110, 178, and 220 g/day with the LP, MP, and HP diets respectively and the corresponding quantities of crude protein (6.25 x nitrogen in forms other than ammonia) apparently digested in the intestines (DCP,) were 75, 134, and 179 g/day. The LP and HP diets provided about 12 and 23 g DCP1/lOO g digestible organic matter respectively; the value for the MP diet was estimated to be 18 g DCP1/100 g. The rates of liveweight increase were 153 � 16, 240�9, and 267�12 g/day with the LP, MP, and HP diets respectively. Wool production was the same with the MP and HP diets but lower with the LP diet. The level of intake of DCP1 and the DCP1/digestible organic matter ratio had little effect on the gross chemical composition of the lambs, as estimated indirectly from tritiated water space. The levels of essential amino acids in peripheral blood plasma were generally in the order HP diet > MP diet > LP diet. Digesta flow from the rumen and abomasum, rumen volume, ruminal volatile fatty acid concentration, and pH of ruminal digesta were similar with the LP and HP diets. It was concluded that a level of about 18 g DCP1/100 g digestible organic matter was adequate for the expression of maximum VFC and that concentrations in excess of this would have little enhancing effect on liveweight gain or wool production under conditions of ad libitum feeding.

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