Wool prices and sheep breeding objectives - a historical perspective

1994 ◽  
Vol 45 (8) ◽  
pp. 1671 ◽  
Author(s):  
DJ Cottle
Keyword(s):  
Important Determinant ◽  
Moving Average ◽  
Fibre Diameter ◽  
Percentage Increase ◽  
Sire Evaluation ◽  
Selection Indices ◽  
Breeding Objectives ◽  
Fibre Fineness ◽  
The Mean ◽  
Fleece Weight

An analysis of weekly wool prices for different fibre diameter market indicators from 1950 to 1993 was conducted to determine appropriate economic values for the calculation of sheep selection indices. An important determinant of breeding objectives and selection indices is the percentage increase in the value of wool for each 1 8m reduction in fibre diameter, termed index percentage (IP). From 1950 to 1981 the appropriate IP value for fine (20 8m), medium (21 8m) and strong (23 8m) wool Merinos was 5%. From 1981 to 1993 the mean weekly IP values for fine, medium and strong wool Merinos were about 20, 15 and 8% respectively. The 5 year moving average IP values in 1993 for fine, medium and strong wool Merinos were 25, 20 and 8% respectively. The distributions of weekly wool prices and IP values are not normal and are positively skewed. Therefore, a safer, more conservative approach is to calculate the median weekly IP values for any period or to use median weekly wool prices to calculate IP values. The median weekly IP values for 1981-1993 were 20, 11 and 8% for fine, medium and strong Merino wools respectively. Thus recently there has been a larger relative premium for fibre fineness which could be a permanent trend. Selection efficiencies for clean fleece weight and fibre diameter in fine and strong wool Merinos are predicted to be at least 90% when 10% and 5% indices are used respectively. Selection efficiency in medium wool Merinos when a 5% index is used is only 79% if the 'true' IP is 15%, or 90% if the 'true' IP is 10%. The 10% and 5% indices are currently calculated and made available to the ram owners who participate respectively in the N.S.W. Merino fine and medium wool sire evaluation schemes. It is suggested that there is a case for using indices with higher fibre diameter premiums (i.e. 20% and 10% respectively), than those currently provided in the fine and medium wool schemes.

The influence of selection and plane of nutrition on the components of fleece weight in Merino sheep

1958 ◽  
Vol 9 (6) ◽  
pp. 802 ◽  
Author(s):  
RB Dun
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Small Contribution ◽  
Cross Sectional ◽  
Single Character ◽  
The Mean ◽  
Low Levels ◽  
The Difference ◽  
Fleece Weight ◽  
High Level

The components of clean fleece weight were examined in five experimental flocks of medium-wool Peppin Merinos. Four single-character selection groups – clean fleece weight plus, clean fleece weight minus, crimps per inch plus, and crimps per inch minus – were examined by measuring fleece production in 18-month-old ewe progeny. Measurements were also made on progeny from the "nucleus" flock, which was selected for clean fleece weight with subsidiary selection for crimps per inch and against fold score. Data were collected in 1952 and 1954. The 1954 figures were obtained from a nutrition experiment in which sheep mere grown from weaning to 18 months on a high and on a low plane of nutrition. The mean measurements of the components of clean fleece weight (W) were compared between flocks using the "percentage deviation" technique. Four comparisons were made: (1) Nucleus/Fleece minus; (2) Fleece plus/Fleece minus; (3) Crimps minus/Crimps plus; (4) high nutritional plane/low nutritional plane. In comparisons (1) , (2), and (3), difference in weight of wool per unit area of skin (w) accounted for nearly all the difference in W. Body weight (S) made a small contribution while difference in fold score (R) was negligible. Fibre density (N) accounted for +86 per cent., and fibre cross-sectional area (A) for –28 per cent., of the difference in W in comparison (1). In comparison (2) the figures were N +47 per cent., A +21 per cent., while the figures for comparison (3) were N –26 per cent., A +121 per cent. The increase in fleece weight was invariably accompanied by a decrease in crimps per inch. In all three comparisons primary density (P) was the major cause of change in N. Fibre length (L) made a uniform contribution of approximately +15 per cent. in the three comparisons.The relative importance of the components of fleece weight was similar at both high and low levels of nutrition.The effect of a high level of nutrition was to produce large increases in A, L, and S. The increase in S was compensated by an equal decrease in P. The increase in fibre diameter was not associated with any change in crimps per inch.

The long-term influence of superphosphate and stocking rate on the production of spring-lambing Merino sheep in the high rainfall zone of southern Australia

1999 ◽  
Vol 50 (7) ◽  
pp. 1179 ◽  
Author(s):  
J. W. D. Cayley ◽  
G. A. Kearney ◽  
G. R. Saul ◽  
C. L. Lescun
Keyword(s):  
Fibre Diameter ◽  
Subterranean Clover ◽  
The Body ◽  
Stocking Rate ◽  
Gross Margin ◽  
Single Superphosphate ◽  
Merino Sheep ◽  
Predetermined Level ◽  
The Mean ◽  
Fleece Weight

The productivity of spring-lambing fine wool Merino sheep grazing pastures sown in 1977 to perennial ryegrass and subterranean clover was assessed from 1989 to 1998. The pastures were fertilised each autumn with single superphosphate at 6 levels, and were stocked at a low, medium, or high stocking rate (SR) at each level of fertiliser. The average phosphorus (P) applied annually since sowing (P ) ranged from 1.6 to 32.9 kg/ha. The SRs used varied with fertiliser level in that they were higher where more fertiliser had been applied, so that the highest SR at each level of fertiliser ensured that the pastures were well utilised. Each ewe raised 1 lamb, which was removed at weaning. The influence of fertiliser on the productivity of the sheep at 4 classes (1–4) of SR (mean SR = 7.1, 10.1, 12.6, and 18.2 ewes/ha for classes 1–4, respectively) was described by: y = A−BCP, where y represents production per sheep (kg), and A, B, and C are constants. For greasy fleece weight, estimates of B and C were 1.59 and 0.84; and for SR classes 1–4, the estimates of A were 5.06, 4.89, 4.78, and 4.46, respectively. For weaning weight of lambs, estimates of B and C were 8.4 and 0.82, and estimates of A were 23.5, 22.7, 21.5, and 20.9 for SR classes 1–4. The mean fibre diameter (µm) of the wool was described by: D = 14.18+1.48 GW, where GW is the mean greasy wool produced annually per sheep (kg) averaged over all sheep and years for each of the 18 treatments. The price (cents/kg) of wool with a fibre diameter D (P D) was given by: P D = 12197+4.94P2 + 688D−0.1945P20D − 5810√D, where 20 µm wool is P20 cents/kg. Supplements were fed if the body condition of ewes fell to a predetermined level. The supplement fed per ewe each year (S), expressed as metabolisable energy (in MJ) was described by: S = −602 − 44.1S R + 178.5P + 8.71S R P +539 √SR− 338.5√P−70.8P√SR, where S R and P represent the mean stocking rate (ewes/ha) and mean P applied annually. When a current set of costs and prices was applied to these equations, the maximum gross margin for a SR of 7.1 ewes/ha was $AU119/ha with 8.6 kg P/ha applied annually, and $AU262/ha for SR of 18.2 ewes/ha with 17.6 kg P/ha applied annually. If income derived from sheep is maintained constant, intensifying the sheep enterprise from the low to the high SR system would involve increasing sheep numbers by about 17%, but would release about 55% of the farm’s area for another purpose.

Inclusion of skin follicle traits in selection indices in breeding programs improves genetic gain in Australian fine-wool Merinos

2007 ◽  
Vol 58 (9) ◽  
pp. 921 ◽  
Author(s):  
M. Asadi Fozi ◽  
J. H. J. Van der Werf ◽  
A. A. Swan
Keyword(s):  
Body Weight ◽  
Coefficient Of Variation ◽  
Genetic Parameters ◽  
Genetic Correlations ◽  
Fibre Diameter ◽  
Selection Criterion ◽  
Breeding Programs ◽  
Breeding Objectives ◽  
Staple Strength ◽  
Fleece Weight

Genetic parameters for skin follicle traits, wool traits, body weight, and number of lambs weaned per ewe joined were estimated for 5108 10-month-old Australian fine-wool Merinos born between 1990 and 1996. These animals were descended from 261 sires and 2508 dams. The skin follicle number index that is based on skin surface area, and primary, secondary, or total follicle density were introduced as possible early-age selection criteria estimated at 6 months of age. Heritability estimates for total, secondary, and primary follicle number index were 0.45 ± 0.04, 0.46 ± 0.04, and 0.38 ± 0.04, respectively. The genetic correlations of total follicle number index with clean fleece weight, mean fibre diameter, staple strength, coefficient of variation of fibre diameter, body weight, and number of lambs weaned were 0.16, –0.67, 0.00, 0.03, 0.22, and 0.22, respectively. Responses to selection on indices including and excluding follicle traits were calculated based on the genetic parameters estimated, and with annual responses calculated using an optimised age structure. On average, 10% greater response was predicted when total follicle number index was used as an additional selection criterion in different micron premium scenarios. In comparison, skin follicle density had a smaller effect on genetic improvement. The extra response was ~1%. Similar index responses were obtained when total follicle number index was used as a replacement selection criterion for clean fleece weight, mean fibre diameter, and coefficient of variation of fibre diameter for breeding objectives with low emphasis on fibre diameter. In objectives with high emphasis on fibre diameter, unfavourable correlated responses in staple strength and CV of fibre diameter limited the effectiveness of using total follicle number index as a selection criterion. Although the use of total follicle number index as an additional selection criterion can be favourable for some breeding objectives, measuring this trait is currently cost prohibitive to inclusion in Merino breeding programs.

Response to the use of Merino in improvement of coarse-wool Barki sheep: an analysis of some cross-bred wool traits

1980 ◽  
Vol 95 (2) ◽  
pp. 339-347 ◽  
Author(s):  
R. A. Guirgis
Keyword(s):  
General Trend ◽  
Fibre Diameter ◽  
Average Percentage ◽  
Mean Diameter ◽  
The Mean ◽  
Fleece Weight ◽  
Selection Of ◽  
Total Average ◽  
Staple Length

SUMMARYA study was carried out during three successive years from 1970 to 1972 on different wool types. Breed groups involved were Merino (M), coarse-wool Barki sheep and five of their crosses. Traits studied were greasy-fleece weight, clean-fleece weight, kemp score and means of staple length and fibre diameter in the whole fleece.The heaviest greasy fleeces were produced by ¾ followed by ⅝ M. Total average greasy fleece weight of the crosses was 3·43 kg. There was a general trend of increase in greasy fleece weight with increasing Merino proportion.The total average percentage clean yield of the crosses was 42·2, and ½ M and ¾ M produced the heaviest clean fleeces. The total average clean fleece weight of the crosses was 1·44 kg. Skirting the fleeces caused a reduction in the within-fleece variability of staple length and diameter. Percentages reduction for staple length were 10·3, 9·6 and 14·6 and those for fibre diameter were 2·4, 5·0 and 9·5 in Barki, crosses and Merino respectively.Barki had the coarsest diameter and the whole fleece of ¾ M showed the finest mean diameter of the crosses. The within-staple variability in distribution of fibre diameter was high in Barki and throughout the crosses. The average percentage medullated fibres was highest in Barki and decreased throughout the series of crosses. The ¼ M had the highest frequency medullated fibres of the crosses.The longest mean staple in the crosses was produced by ¼ M. The within-fleece variability in staple length was generally low. In the crosses, the variability assumed slightly higher values than those of the parental breeds.Kemp production was mainly contributed from the dorsal line, particularly from the back and hip.As regards some wool and mutton characteristics, ⅝ M might be considered the most suitable cross-bred type.With increasing Merino contribution in the crosses, the mean fibre diameter showed a decreasing trend, but a high within-staple variability was maintained throughout the crosses. Inter se mating, in most of the crosses, produced animals that showed relatively more uniformity between fleeces than either both or one of the crosses. Inter se mating of the different cross-bred types with selection of the desired uniformity in length and diameter would be recommended.

Lamb mortality and growth to weaning in commercial Merino flocks in Western Australia

1992 ◽  
Vol 43 (6) ◽  
pp. 1399 ◽  
Author(s):  
RW Kelly
Keyword(s):  
Western Australia ◽  
Fibre Diameter ◽  
Mortality Rates ◽  
Unit Change ◽  
Condition Score ◽  
Average Condition ◽  
The Mean ◽  
Staple Strength ◽  
Fleece Weight ◽  
Highly Correlated

Eighteen farm flocks of four-tooth Merino ewes (average of 371 ewes at lamb marking, range 278 to 511) were studied in 1987/88 ( n =8 ) and 1988/89 (n=10) over the period from 2 to 4 weeks pre-joining until 12 weeks post-lambing. All farms were located in the south-west of Western Australia, and the flocks started lambing between mid-April and mid-July. The average liveweights of ewes pre-joining ranged over 40.2 to 61.8 kg, and average condition scores ranged from 2.2 to 4.2. Mean liveweight changes of the ewes ranged over losses of up to 8.5 kg to gains of up to 10.4 kg between consecutive recordings at 2 to 3 month intervals up to 12 weeks post lambing, and condition score changes ranged over minus 1.2 to plus 1.2. The greatest losses in liveweight and condition score in many flocks corresponded with the period from mid-pregnancy to marking, the time of greatest nutrient demand of the ewe. There was considerable variation between flocks in the percentage of dry ewes (2.9 to 17.7%), lambs born per ewe present at marking (83.0 to 147.3%), lambs alive per ewe present at marking (66.3 to 123.2%), and lamb deaths as a percentage of total lambs born (10.9 to 29.8%). For single and twin-born lambs, the percentage of lamb deaths between flocks ranged from 6.0 to 19.9% (mean = 11.0%) and 19.1 to 63.2% (mean = 33.1%) respectively. Of the ewes giving birth to twins, an average of 9.6% lost both lambs. The mean birthweights were 4.4 kg (range 3.6 to 5.1 kg) for singles and 4.0 kg (range 3.3 to 4.5 kg) for twins, and were highly correlated (r = 0 - 74, n = 13 flocks, P<0.01). Lamb growth to marking averaged 232 g head-1 day-1 and 205 g head-1 day-1, and from marking to weaning 198 g head-1 day-1 and 193 g head-1 day-1 for single and twin-born lambs respectively. The mortality rates of both single and twin-born lambs were highly correlated with mean liveweight of the ewes at mid-pregnancy (r = -0.64, P<0.01; r = -0.75, P<0.001; respectively). A kilogram increase in mean liveweight at mid-pregnancy was associated with declines in the mortality rates of single-born lambs of 0.7% units (s.e. = 0.23), and of twin-born lambs of 2.2% units (s.e. = 0.57). Mortality rates of the singles were highly correlated with that of twins (r = 0.86, P<0.001), with a 1% unit change in death rate of singles being associated with a 2.5% (s.e. = 0.41) unit change for twins. Mortality rates of twins were associated with mean cotyledon diameter measured in mid-pregnancy (r = -0.48, n = 13, P<0. l0), and mean umbilical resistance to blood flow (r = 0.78, n = 9, P<0.02). Growth from birth to weaning of single-born lambs was associated with the mean liveweight of the flock in mid-pregnancy (r = 0.72, P<0 .001). Clean fleece weight and mean fibre diameter of the fleeces from single.bearing and rearing ewes were correlated with mean ewe liveweight in mid-pregnancy (r = 0.56, P<0.05; r = 0.70, P<0.01; respectively). Staple strength was correlated with mean ewe liveweight at marking for both single and twin producing ewes (r = 0.72, n = 18, P<0.01; r = 0.74, n = 9, P<0.05; respectively). It was concluded that liveweight of the ewe in mid-pregnancy, which represents the sum of starting liveweight and liveweight change, is the most important single and practical criterion that can be used by a farmer to set the goals for nutritional management of the flock over pregnancy to improve lamb survival.

The effect of previous and current nutrition on wool production in southern Victoria

1962 ◽  
Vol 2 (6) ◽  
pp. 160 ◽  
Author(s):  
MJ Sharkey ◽  
IF Davis ◽  
PA Kenney
Keyword(s):  
Fibre Diameter ◽  
Fibre Length ◽  
Initial Increase ◽  
Nutritional Treatment ◽  
Wool Production ◽  
Wool Growth ◽  
Short Period ◽  
The Mean ◽  
Fleece Weight ◽  
Autumn And Winter

The effect of different planes of nutrition on the wool production of Corriedale wethers at pasture was studied between August 1959 and December 1960. The plane of nutrition was controlled by rate of stocking. The effect of previous nutritional treatment on wool production was slight. It affected wool weight and fibre length for 160 one month and fibre diameter for two months. The differences in current nutritional treatment were accompanied by large differences in wool production except during the spring months. On the highest plane of nutrition the wool production showed little seasonal variation, apart from an initial increase in production during the autumn. On the medium and low planes of nutrition wool growth declined substantially in autumn and winter and increased again in spring. The mean fibre diameter of the wool that was clipped frequently was greater than that of fleece wool obtained from the opposite midside at shearing. Further, in the groups on medium and low planes of nutrition estimates of fleece weight based on the combined weight of periodical clippings were greater than actual fleece weights. It is concluded that, in the dry Victorian summer, wool production is influenced by the plane of nutrition in the previous spring for a short period only, and that in autumn and winter it is dependant almost entirely on the feed immediately available.

Fleece characteristics and postnatal fleece development in Finnish Landrace × Merino sheep

1972 ◽  
Vol 15 (1) ◽  
pp. 75-84 ◽  
Author(s):  
M. L. Ryder ◽  
D. T. Wilson
Keyword(s):  
Fibre Diameter ◽  
Variable Length ◽  
Primary Follicle ◽  
Merino Sheep ◽  
Fibre Development ◽  
The Mean ◽  
Commercial Value ◽  
Fleece Weight ◽  
Staple Length

SUMMARY1. Fleece characteristics in Finnish Landrace × Merino and Merino × Finnish Landrace sheep were compared with those of the parental breeds, and although most characters in the crossbreds showed no significant departure from the parental mean, they had similarities to the Merino which imparted commercial value.2. The wool was mostly of 60s quality compared with 58s in the Finnish Landrace, and 64s and over in the Merino parents. Crimp number showed heterosis, being 5 to 6 per cm in the crossbreds compared with 2 in the Finnish sheep and 7 in the Merino.3. The mean fleece weight was 3-5 kg, compared with 2-2 kg in the Finnish sheep and 4-2 kg in the Merino.4. The mean staple length was 13 cm compared with a very variable length around a mean of 16 cm in the Finnish Landrace, and 10 cm in the Merino.5. The fibre diameter was nearer to that of the Merino, but not significantly so (primary mean 29·2 μ, secondary mean 26·6 μ).6. The greater fleece weight of the crossbreds would be expected to be associated with a greater skin follicle density, but they had a secondary/primary follicle ratio of about 10 (compared with 5 in the Finnish Landrace and 20 in the Merino), which did not differ significantly from the parental mean.7. There was some evidence that fibre development was initially more rapid in the crossbred lambs.

Optimal use of on-farm fibre diameter measurement and its impact on reproduction in commercial Merino flocks

2007 ◽  
Vol 47 (5) ◽  
pp. 525 ◽  
Author(s):  
M. J. Kelly ◽  
A. A. Swan ◽  
K. D. Atkins
Keyword(s):  
Selection Index ◽  
Fibre Diameter ◽  
Diameter Measurement ◽  
Average Fibre Diameter ◽  
Genetic Components ◽  
Reproduction Traits ◽  
The Mean ◽  
Fleece Weight ◽  
The Individual ◽  
On Farm

The use of on-farm measurement of fibre diameter in clip preparation and selection was examined using a stochastic simulation. Commercial self-replacing Merino flocks were simulated, with each flock equivalent in stocking rate to a 2500-ewe flock with an average fibre diameter of 19 µm (with the same energy requirements as 4250 50-kg dry sheep). Returns from each selection and clip preparation strategy were based on a 5-year period from 1998 to 2003. The percentage of sales where it would have been profitable to utilise fibre diameter measurement in wool classing declined from 84% to less than 1% in 19- and 25-µm flocks, respectively. Clip preparation benefits reduced from AU$5.52 to $1.46 per dry sheep equivalent as the mean fibre diameter of the flock increased from 19 to 25 µm (under random selection). Selection on either fibre diameter or selection index (12% micron premium based on fibre diameter and fleece weight) was of benefit for 19- and 21-µm flocks, but not broader fibre diameter flocks. Flock reproductive performance was simulated at the individual animal level, based on the traits of fertility (ewes lambing per ewe joined), litter size (lambs born per ewe lambing) and lamb survival (lambs weaned per lamb born). These traits were simulated with genetic components, allowing the investigation of correlated responses in reproduction traits. Single-trait selection on fibre diameter did not significantly impact on reproduction traits but did reduce fibre diameter, fleece weight and bodyweight. There was a large variation in the returns from clip preparation, as the mean fibre diameter of the flock increased, and over selling periods, highlighting the importance of understanding the current market conditions and their relationship with the flock mean fibre diameter when considering the use of fibre diameter in clip preparation.

scholarly journals Reservoir Sizing at Draft Level of 75% of Mean Annual Flow Using Drought Magnitude Based Method on Canadian Rivers

Hydrology ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 79
Author(s):  
Tribeni C. Sharma ◽  
Umed S. Panu
Keyword(s):  
Standard Deviation ◽  
Time Scale ◽  
Moving Average ◽  
Flow Data ◽  
Truncation Level ◽  
Drought Intensity ◽  
Error Margin ◽  
Reservoir Volume ◽  
The Mean ◽  
Reservoir Sizing

On a global basis, there is trend that a majority of reservoirs are sized using a draft of 75% of the mean annual flow (0.75 MAF). The reservoir volumes based on the proposed drought magnitude (DM) method and the sequent peak algorithm (SPA) at 0.75 MAF draft were compared at the annual, monthly and weekly scales using the flow sequences of 25 Canadian rivers. In our assessment, the monthly scale is adequate for such analyses. The DM method, although capable of using flow data at any time scale, has been demonstrated using monthly standardized hydrological index (SHI) sequences. The moving average (MA) smoothing of the monthly SHI sequences formed the basis in the DM method for estimating the reservoir volume through the use of the extreme number theorem, and the hypothesis that drought magnitude is equal to the product of the drought intensity and drought length. The truncation level in the SHI sequences was found as SHIo [ = (0.75 ‒ 1) µo/σo], where µo and σo are the overall mean and standard deviation of the monthly flows. The DM-based estimates for the deficit volumes and the SPA-based reservoir volumes were found comparable within an error margin of ±18%.

Retirement intentions of older consultant psychiatrists

2004 ◽  
Vol 28 (4) ◽  
pp. 130-132 ◽  
Author(s):  
Alex Mears ◽  
Tim Kendall ◽  
Cornelius Katona ◽  
Carole Pashley ◽  
Sarah Pajak
Keyword(s):  
Early Retirement ◽  
Response Rate ◽  
Important Determinant ◽  
Clinical Implications ◽  
Consultant Psychiatrist ◽  
Health Officer ◽  
Decisions To Leave ◽  
The Mean ◽  
The Uk ◽  
Retirement Intentions

Aims and MethodThis survey gathered data on the retirement intentions of consultant psychiatrists over the age of 50 years, in order to address retention issues. A questionnaire was sent to all 1438 consultants over this age in the UK.ResultsA total of 848 questionnaires were returned, an adjusted response rate of 59%. The mean age at which consultants intended to retire in this sample was 60 years (s.d. 4.16), suggesting a potential loss of 5725 consultant years. Reasons for early retirement are complex: factors encouraging retirement include too much bureaucracy, lack of free time and heavy case-loads; those discouraging retirement include enjoyment of work, having a good team and money. Mental Health Officer status is an important determinant in the decision to retire early.Clinical ImplicationsWith numerous vacancies in consultant psychiatrist posts throughout the UK, premature retirement is a cause for concern, possibly contributing to an overall reduction in consultant numbers of 5%. Addressing factors that influence consultants' decisions to leave the health service early should form an important part of an overall strategy to increase consultant numbers.

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